WO2021254951A1

WO2021254951A1 - Expandable last for furnishing footwear with an insert and method for furnishing footwear with an insert

Info

Publication number: WO2021254951A1
Application number: PCT/EP2021/065935
Authority: WO
Inventors: Stefan Hauer; Maximilian Muth; Jens Heidenfelder
Original assignee: W. L. Gore & Associates Gmbh
Priority date: 2020-06-17
Filing date: 2021-06-14
Publication date: 2021-12-23
Also published as: EP4167791A1; CN116056601A; US20230320462A1

Abstract

An expandable last (2) for furnishing footwear (110) with an insert (100) includes an expansion assembly (40); an expandable shell (6), arranged around the expansion assembly (40); and a liquid chamber (8) within the expandable shell (6); wherein the expandable last (2) is insertable into the footwear (110) through a collar of the footwear (110) and wherein the expandable shell (6) is configured to expand for pressing the insert (100) towards an inside of the footwear (110); and wherein the expansion assembly (40) is configured to adapt its extension for exerting localized pressure onto the expandable shell (6) towards the inside of the footwear (110).

Description

Expandable Last for Furnishing Footwear with an Insert and Method for Furnishing Footwear with an Insert

The present invention is in the field of producing footwear. In particular, the present invention is in the field of equipping footwear with an insert.

In recent years, there has been a trend towards waterproof shoes. Waterproof and breathable shoes have been developed that provide for an all-around waterproof structure around the wearer's foot, but at the same time provide breathabil- ity, such that moisture and sweat from the wearer's foot can escape from the in terior of the shoe. While such waterproof and breathable shoes provide a very convenient feel for the user in a wide range of usage scenarios, the percentage of waterproof footwear among all shoes is still relatively low.

Accordingly, it would be beneficial to provide equipment that allows for waterproofing footwear, while maintaining a high degree of flexibility in the footwear production process. It would further be beneficial to provide a method that allows for waterproofing footwear, while maintaining a high degree of flexibility in the footwear production process.

Exemplary embodiments of the invention include an expandable last for furnishing footwear with an insert, comprising: a form-stable core support element; an expandable shell, arranged around the core support element; a liquid chamber within the expandable shell; and a liquid port, providing liquid communication between the liquid chamber and an external liquid source; wherein the expand able last is insertable into the footwear through a collar of the footwear and wherein, when receiving liquid in the liquid chamber via the liquid port, the ex pandable shell is configured to expand for pressing the insert towards an inside of the footwear.

Exemplary embodiments of the invention allow for equipping footwear with an insert in a flexible and efficient manner. In particular, exemplary embodiments of the invention allow for equipping footwear with an insert on the inside thereof, when the collar is the only access point to the interior of the footwear. Further in particular, exemplary embodiments of the invention allow for equipping footwear with an insert, when the footwear is otherwise already completely assembled or close to being completely assembled. Footwear may be equipped with a waterproof, breathable insert, such as a waterproof, breathable bootie, and may thus be made waterproof in a convenient, flexible, and efficient manner. In particular, when the footwear has been designed and assembled in accordance with a conventional non-waterproof design and is ready to be worn or close to being ready to be worn, it can still be equipped with a waterproof, breathable insert. In the case of footwear that is ready to be worn, it may also be said that readily assembled non-waterproof footwear may be retrofitted with a waterproof, breathable insert and may, thus, be made waterproof.

According to exemplary embodiments of the invention, the expandable last is in- sertable into the footwear through a collar of the footwear, and the expandable shell is configured to expand, when receiving liquid in the liquid chamber via the liquid port, for pressing the insert towards an inside of the footwear. The expandable last may be conveniently introduced into the interior of the footwear, and the expandable shell may exert pressure onto the insert with a high degree of uniformity. With the expandable shell expanding upon receiving liquid in the liquid chamber via the liquid port and engaging with the insert, the pressure-balancing effect, inherent to liquids, may be taken advantage of in very close proximity to the insert. With the expandable shell forming the barrier between the liquid chamber, in which the pressure is built up, and the insert, a highly direct and highly uniform pressure may be exerted onto the insert for pressing the insert towards the inside of the footwear. The expandable shell is configured to expand and, thus, to press the insert towards the inside of the footwear during operation of the expandable last. It is understood that the expandable last is configured to receive liquid in the liquid chamber in operation and that the expandable shell is configured to exert the pressure on the insert in operation, when arranged in the footwear.

According to exemplary embodiments of the invention, the expandable last is configured for furnishing footwear with an insert. In particular, the expandable last may be configured for any one or any subset or all of inserting an insert into the interior of the footwear, positioning an insert in the interior of the footwear, mechanically engaging an insert with the inside of the footwear, and attaching / adhering an insert to the inside of the footwear. The expandable last is configured to exert pressure onto an insert against the inside of the footwear via the expandable shell. The expandable last has a form-stable core support element. The term form- stable core support element relates to a core support element that has a substantially stable shape. In particular, it relates to a core support element that has no active shape adjusting means, such as a spring-loaded actuator, a hydraulic or pneumatic actuator, etc. The term form-stable does not exclude the core support element to have some elasticity and/or allow for some plastic deformation. For example, the core support element may elastically and/or plastically deform, while being pushed into the interior of the footwear. However, by being form-stable, the core support element maintains its general shape. The shape of the core support element may not undergo a substantial transformation and may maintain its general appearance.

The expandable last has an expandable shell, arranged around the core support element. The expandable shell may be made of any material that expands under the pressure of the liquid in the liquid chamber. The expansion of the expandable shell may comprise an elastic deformation and/or a plastic deformation. The expandable shell may be a kind of balloon / bladder that expands upon receiving li quid in the liquid chamber. In particular, the expandable shell may be a balloon around the form-stable core support elements, with the liquid chamber being formed on the inside of the balloon. The expandable shell may be expandable at portions thereof or may be expandable substantially everywhere. In other words, the expandable nature of the shell may be provided in portions thereof or across the whole component. The expandable shell may thus be configured to press the insert towards the inside of the footwear at selected portions of the insert or substantially everywhere along the insert. The expandable shell may be substantially foot-shaped. The foot-shaped nature of the expandable shell may be present in the un-expanded state. It is also possible that the expandable shell assumes a kind of foot shape, when receiving liquid in the liquid chamber.

The expandable last comprises a form-stable core support element and an ex pandable shell, arranged around the core support element. In this way, the stability / re-enforcing strength of the core support element is combined with the expandable properties of the expandable shell. In this way, a good compromise between insertibility of the expandable last and adaptability to the inside contour of the footwear may be achieved.

The expandable last is insertable into the footwear through a collar thereof. In other words, the expandable last is insertable into the footwear through a foot in- sertion opening of the footwear. In yet other words, the expandable last is insert- able into the footwear from the top, when placing the footwear on a table or other horizontal structure in its normal use orientation.

The expandable last comprises a liquid chamber within the expandable shell. The expandable shell may be liquid-tight / liquid proof, in particular water-tight / waterproof. With liquid, in particular water, being used in the liquid chamber in operation, the insert can be pressed towards the insert of the footwear in a particularly efficient manner. As compared to using gas for exerting the pressure, a lower amount of fluid may needed and the need for a high gas pressure may be elimin ated. For example, in particular applications, a water pressure of about 0.2 bar may be suitable for pressing an insert towards the inside of the footwear, while air pressures of 6-7 bar would be required for achieving comparable results. Many expandable materials cannot handle such high pressures and would burst / tear, such that the using of liquids provides a much higher degree of design flexibility than using gases for expanding the expandable shell. Also, liquids have beneficial properties, when counter pressure from the outside of the footwear is applied. For example, when applying counter-pressure in a pressure chamber, as described below, the non-compressibility of the liquid allows for using comparably low liquid pressures. As compared thereto, the compressed air within the expandable shell would have to have a much higher pressure, in order to avoid compression due to the counter pressure.

The expandable last has a liquid port, providing liquid communication between the liquid chamber and an external liquid source. A liquid-tight seal may be provided between the liquid chamber and the liquid port. The liquid port may have a connection piece for attaching a liquid line towards the external liquid source. This connection piece may be any suitable male or female, threaded or unthreaded connection piece. It may have a suitable locking mechanism for ensur ing a safe connection between the liquid port and the external liquid source / the liquid line. The terminology of the liquid port providing liquid communication between the liquid chamber and an external liquid source means that the liquid port has the capacity to pass liquid therethrough and to allow for liquid communic ation between the liquid chamber and the external liquid source in operation.

With the expandable last having an expandable shell, the expandable last may be used over a range of shoe sizes. In particular, it is possible that the expandable last is suitable for being used for a range of up to 2 or 3 or 4 or 5 or 6 or 7 or 8 shoe sizes (European shoe sizes). It may thus be possible to cover the whole range of standard adult shoe sizes, i.e. European shoe sizes 35 to 47, with two or three different expandable lasts only. Further, the expandable last may be used for a variety of different shoe styles, with the expandable shell adapting to the in ner contour of the footwear via the liquid in the liquid chamber.

According to a further embodiment, the core support element is substantially L- shaped or substantially T-shaped or substantially U-shaped or substantially footshaped. In this way, the core support element may be particularly suitable for providing a high degree of stability to the expandable last. The core support ele ment may be dimensioned to extend over at least 50%, in particular over at least 70%, further in particular over between 90% and 100% of the vertical extension of the interior of the footwear and/or over at least 30%, in particular over at least 50%, further in particular over at least 70%, or even over between 90% and 100% of the horizontal extension of the interior of the footwear.

According to a further embodiment, the core support element is rigid. In particular, the core support element may be made of metal or made of a rigid plastic material or made of sintered material. The core support element may be considered rigid in case it does not undergo a deformation during manual introduction of the expandable last into the footwear. The rigid core support element may provide a high degree of stability to the expandable last during use in the footwear.

According to a further embodiment, the core support element is flexible. In particular, the core support element may be resilient, further in particular made from re silient rubber material. The core support element may be considered flexible in case its shape changes temporarily or permanently during manual introduction of the expandable last into the footwear. A flexible core support element may be particularly suitable for an easy introduction of the expandable last into the interior of the footwear. A resilient core support element may provide a good compromise between easy insertability and a high degree of stability, when inserted into the footwear. The core support element may be made from any suitable flexible material. Suitable flexible materials include rubber, polyurethane, silicone, and thermoplastic polyurethane materials. The selection of a rigid material or a flexible material for the core support element may be made dependent on the dimensions of the core support element. In case the dimensions of the core support element are close to the dimensions of the interior of the footwear, a flexible material may allow for a much easier insertability through the collar of the footwear. In case the dimensions of the core support element are substantially smaller than the dimen sions of the interior of the footwear, insertability may be less of an issue and a ri gid material may be selected.

According to a further embodiment, the liquid chamber comprises substantially the entire volume between the core support element and the expandable shell. In this way, the expandable last is highly flexible, having a large liquid volume in the liquid chamber during operation. The liquid chamber covering such a large volume may also allow the expandable last to have an overall low number of components. In a particular embodiment, the expandable last may be free of addi tional components between the form-stable core support element and the ex pandable shell, with the volume between the form-stable core support element and the expandable shell forming the liquid chamber. However, it is also possible that additional components are provided between the core support element and the expandable shell. For example, filler elements, such as filler balls or cuboid filler elements, may be provided between the core support element and the ex pandable shell. Such filler elements may be free-floating between the core support element and the expandable shell and/or may be attached to the core sup port element and/or the expandable shell. The filler elements may reduce the liquid volume needed for generating a desired pressure on the insert by the expandable shell. In this way, the furnishing of the footwear with the insert may be achieved in a particularly short time frame.

According to a further embodiment, the core support element comprises at least one liquid supply line, coupled to the liquid port and providing liquid communication between the liquid port and the liquid chamber. The liquid may reach the liquid chamber at one or more desired locations via the at least one liquid supply line. The entirety of the liquid supply lines may also be referred to as liquid supply line system. The at least one liquid supply line may have one or more openings towards the liquid chamber. An efficient distribution of the liquid in the liquid chamber may be achieved, and a beneficial dynamic build-up of the pressure within the expandable shell may be made possible via a suitable design of the liquid supply line system and the opening(s).

According to a further embodiment, the at least one liquid supply line is arranged within the core support element and has at least one opening towards the liquid chamber. The core support element may serve the double purpose of providing stability to the expandable last and helping the liquid distribution in the liquid chamber by housing the at least one liquid supply line.

According to a further embodiment, the expandable shell is elastic. In particular, the expandable shell may be made from any kind of elastic material that is suitable for expanding under liquid pressure and for applying pressure to the insert. The expandable shell may be made from latex material. In particular, the expandable shell may be made from natural latex material or synthetic latex material. It is also possible that the expandable shell is made from another kind of rubber ma terial. Rubber materials, in particular latex materials, may provide for a good compromise between expandability and robustness with respect to changing pres sures. Other suitable elastic materials are stretchable membrane materials and multilayer constructions. The expandable shell may be made from a liquid proof, in particular waterproof, material.

According to a further embodiment, the expandable shell is a one-layer structure or a two-layer structure or a three-layer structure. It is also possible for the expandable shell to have a higher number of layers. With the expandable shell hav ing a two-layer or three-layer design, a good compromise between expandability and tear-resistance may be achieved. The two / three layers may be co-extens- ive. It is also possible that re-enforcing patches may be provided in critical por tions of the expandable shell, thus forming a multi-layer structure at selected portions. The two / three layers may be made from the same material or may be adapted to the particular requirements on the inside / outside of the expandable shell. For example, an inner layer may be adapted to cooperate well with the liquid in the liquid chamber, while an outer layer may be adapted to cooperate well with the insert. One or more or all of the layers may be made from a liquid proof, in particular waterproof, material.

According to a further embodiment, the expandable shell has, at least in one or more regions thereof, dimension-specific elastic properties. In other words, the expandable shell may stretch in a particular dimension easier / quicker / at lower pressures than in one or more other dimensions. In this way, the expansion of the expandable shell may be controlled for a particular application / for a particular footwear. Further in particular, the resulting shape of the expandable shell and/or the dynamic application of pressure onto different portions of the insert may be controlled via the dimension-specific set-up of the expandable shell. According to a further embodiment, the liquid chamber is at least partly filled with an open-cell foam. In particular, the majority of the liquid chamber or substantially the entire liquid chamber may be filled with an open-cell foam. The open-cell foam may allow the liquid to distribute within the liquid chamber, while giving the liquid chamber some inherent shape. In this way, the expandable last may be inherently shaped similar to the interior of the footwear, while still allowing the liquid to adapt the expandable shell to the inner contour of the footwear. The open-cell foam may be any suitable open-cell form. Suitable open-cell foams include open-cell polyurethane foam, silicone foam, natural foam, and polyethylene foam. The open-cell foam itself may expand upon absorbing liquid. However, it is also pos sible that the open-cell foam substantially maintains its shape upon absorbing li quid. As an alternative / additionally, the liquid chamber may be at least partly filled with a spacer fabric. The spacer fabric may similarly provide some inherent shape to the expandable shell, while allowing the liquid to distribute and "fine- tune” the shape of the expandable shell, when expanding and engaging with the insert. Both the open-cell foam and the spacer fabric have no active shape adjust ing means. They have an inherent shape, which may adapt passively to liquid en tering the open-call foam / spacer fabric.

According to a further embodiment, the expandable last further comprises at least one expandable liquid bag, arranged outside or inside of the expandable shell. In particular, the expandable last may comprise at least one expandable liquid bag, arranged outside of the expandable shell, and/or may comprise at least one expandable liquid bag, arranged inside of the expandable shell. In this way, a local ized adaption of the pressure exerted onto the insert towards the inside of the footwear may be achieved. In particular, the at least one expandable liquid bag may be filled with liquid in such a manner that a different pressure level is reached at the position of the at least expandable liquid bag, as compared to the liquid chamber within the expandable shell. The at least one expandable liquid bag may be used in a number of ways. For example, a higher liquid pressure may be used for pressing the insert harder against the inside of the footwear in posi tions where an attachment between the insert and the footwear is difficult. A lower pressure in the at least one expandable liquid bag may be used for reducing the stress on sensitive portions of the inside of the footwear. The at least one ex pandable liquid bag may be smaller in volume than the liquid chamber, in particular less than 20%, further in particular less than 10%, in volume of the liquid chamber. In this way, the liquid in the at least one expandable liquid bag may be more locally constrained than the liquid in the liquid chamber. The liquid in the at least one expandable liquid bag may be prevented from flowing to portions of the footwear where the footwear yields most easily. The expandable liquid bag may be seen as an additional bladder / balloon, in particular an additional bladder / balloon provided on the outside / inside of the expandable shell.

According to a further embodiment, the expandable last further comprises at least one ancillary liquid port, providing liquid communication between the at least one expandable liquid bag and at least one external liquid source. Said at least one external liquid source may be one or more separate liquid sources or may be / contain the same external liquid source, as used for the liquid chamber within the expandable shell. With the at least one ancillary liquid port and the one or more separate external liquid sources, if present, the at least one expandable liquid bag may be used for flexibly controlling the pressure therein, as compared to the pressure within the liquid chamber within the expandable shell.

According to a further embodiment, the expandable last further comprises at least one ancillary liquid supply line, coupling the at least one expandable liquid bag to the at least one ancillary liquid port. In this way, the at least one expandable liquid bag may perform its desired function with a low liquid bag volume, with the ancillary liquid supply line(s) achieving the liquid transfer between the ancillary liquid port(s) and the expandable liquid bag(s). The at least one expandable liquid supply line may run through the liquid chamber within the expandable shell. However, it is also possible that the at least one ancillary liquid supply line runs along the outside of the expandable shell.

According to a further embodiment, the at least one expandable liquid bag comprises: an expandable liquid bag at an instep portion of the expandable shell; an expandable liquid bag at a toe portion of the expandable shell; an expandable liquid bag in a forefoot portion of the expandable shell; an expandable liquid bag in an upper midfoot portion of the expandable shell. The expandable liquid bag at an instep portion of the expandable shell may be arranged on an outside or on an inside of the expandable shell. The expandable liquid bag at a toe portion of the expandable shell may be arranged on an outside or on an inside of the expand able shell. The expandable liquid bag in a forefoot portion of the expandable shell may be arranged in the forefoot portion of the expandable shell in such a manner that it abuts the expandable shell upon expansion. The expandable liquid bag in the upper midfoot portion of the expandable shell may be arranged in the midfoot portion in such a manner that it abuts the expandable shell upon expansion. With the expandable liquid bag at an instep portion of the expandable shell and/or with the expandable liquid bag in an upper midfoot portion of the expandable shell, the insert may be effectively pressed against the inside of the footwear at a tongue portion thereof. An attachment between the insert and the tongue portion of the footwear, which may be difficult due to the particular nature of tongue constructions, may be achieved in an effective manner. With the expandable liquid bag at a toe portion of the expandable shell and/or with the expandable liquid bag in a forefoot portion of the expandable shell, the insert may be effectively pressed against the footwear at a toe portion thereof. An attachment between the insert and the toe portion of the footwear, which may be difficult due to the irregularities of the inner contour in the toe portion and/or due to the comparably stiff nature the toe portion of the footwear, which may act to push the liquid to other portions of the expandable shell, may be achieved in an effective manner.

According to a further embodiment, the at least one expandable liquid bag is at least partly filled with an open-cell foam, in particular with an open-cell polyurethane foam, and/or with a spacer fabric. When filled with liquid, the at least one expandable liquid bag may have a larger extension than the open-cell foam / the spacer fabric. The spacer fabric may be particularly suitable for an expandable li quid bag that has a somewhat flat shape, such as an expandable liquid bag arranged at an instep portion of the expandable shell.

According to a further embodiment, the expandable last further comprises a lid, to which the core support element and the expandable shell are mounted. The lid provides for an effective way to fix a positional relationship between the core sup port element and the expandable shell, while still allowing the two elements to move with respect to each other in portions thereof. While the positional relationship between the core support element and the expandable shell may be fixed at one end thereof, the expandable shell is free to expand and move away from the core support element over a large portion thereof. When the last is inserted into the footwear and the footwear is placed on a table or other horizontal structure in its normal use orientation, the core support element and the expandable shell extend downwards from the lid. In this way, the lid may form an upper end portion of the expandable last, when inserted into the footwear in a normal shoe orientation. This explanation of the relative position of the lid and the core support element / expandable shell does not preclude the lid to be a side portion or a lower portion of the expandable last, when used for furnishing footwear with an insert. In other words, the expandable last may be positioned upside down, i.e. lid down, at se- lected times or during substantially the entire operation of providing the footwear with the insert.

According to a further embodiment, the liquid port is arranged in the lid. In this way, the lid is also the structure of the expandable last that provides for the con nection point to the external liquid source. In particular, the liquid port may be ar ranged in the lid in such a manner that the external liquid source / an external li quid supply line may be attached to the lid. The liquid port may extend through the lid.

According to a further embodiment, the lid has an extension substantially corres ponding to a transverse cross-section of the collar of the footwear. In this way, the lid may have a sufficient extension for mounting the core support element, the expandable shell and, if desired, the liquid port thereto. Also, the expandable shell may be mounted to the lid around a peripheral region thereof. In this way, the ex pandable shell may immediately engage with the insert on the inside of the foot wear upon receiving liquid in the liquid chamber.

According to a further embodiment, the expandable last further comprises a heater configured to heat the liquid in the liquid chamber and/or to heat the ex pandable shell. By heating the liquid and/or the expandable shell, the heater may contribute to the expansion of the liquid and/or may provide a warming / heating of the insert. Such warming / heating of the insert may help in positioning the in sert by making the same more pliable and/or may help in attaching the insert to the inside of the footwear, for example by activating a heat-activated adhesive on the insert. The heater may be an electric heater that may have a power supply line to an external power source. The heater may also have a rechargeable power source, such as a rechargeable battery, which may allow the heater to at least temporarily operate without being coupled to an external power supply.

According to a further embodiment, the expandable last comprises an external heater configured to heat the liquid before being introduced into the liquid chamber. In this way, above described beneficial effects of using heated liquid in the liquid chamber may be achieved, while keeping the core support element / liquid chamber free of heating functionality. The external heater may be arranged at a more easily accessible location and may be designed / operated without the con straints associated with the interior of the footwear. According to a further embodiment, the expandable last is configured for furnish ing the footwear with a waterproof, breathable bootie. In this way, the footwear may be made waterproof with the help of the expandable last. As discussed above, the expandable last may help in making the footwear waterproof at a late stage of the assembly, in particular at a point in time when the collar of the footwear is the only access point to the interior of the footwear. The waterproof, breathable bootie may be embodied in accordance with any of the embodiments, as described in PCT/EP2017/068030 and/or PCT/EP2018/084179, the contents of which are incorporated herein by reference in their entirety.

According to a further embodiment, the expandable last is configured for furnishing the footwear with a waterproof, breathable bootie, wherein the waterproof, breathable bootie is provided, on its outside, with pressure sensitive adhesive and/or heat-activated adhesive for attachment to the inside of the footwear. The pressure sensitive adhesive and/or heat-activated adhesive may be provided on selected portions of the outside of the waterproof, breathable bootie or may be provided substantially all over the outside of the waterproof, breathable bootie. The pressure sensitive adhesive and/or heat-activated adhesive may be provided as a continuous adhesive layer or as an adhesive pattern, such as a dot or stripe pattern. The expandable last may be particularly suitable for inserting the waterproof, breathable bootie provided with adhesive, because the risk of the adhesive getting stuck in undesired positions during the insertion of the expandable last can be kept small by inserting the expandable last in an un-expanded state to gether with the waterproof, breathable bootie. It is pointed out that it is also possible to insert the waterproof, breathable bootie into the footwear with a separate device and to subsequently use the expandable last for exerting the pressure onto the insert towards an inside of the footwear. Further, the attachment between the waterproof, breathable bootie and the inside of the footwear may be supplemented with an adhesive tape in a collar region of the footwear. An adhes ive tape in the collar region of the footwear may also provide for a clean finish, blocking the upper edge of the insert from view and preventing delamination of a multi-layer insert from the upper edge. The term heat-activated adhesive refers to an adhesive that has the capacity to be activated by heat. The heat-activated adhesive may also be referred to as heat-activatable adhesive.

Exemplary embodiments of the invention further include an expandable last for furnishing footwear with an insert, comprising: an expansion assembly; an ex pandable shell, arranged around the expansion assembly; and a liquid chamber within the expandable shell; wherein the expandable last is insertable into the footwear through a collar of the footwear and wherein the expandable shell is configured to expand for pressing the insert towards an inside of the footwear; and wherein the expansion assembly is configured to adapt its extension for exerting localized pressure onto the expandable shell towards the inside of the footwear Exemplary embodiments of the expandable last, having an expansion assembly and an expandable shell, provide an alternative tool for effectively furnishing footwear with an insert, as compared to above described exemplary embodi ments, having a form-stable core support element and an expandable shell. Above described additional features, modifications, and effects are applicable to the expandable last, having an expansion assembly and an expandable shell, in an analogous manner, as long as they are not conceptually excluded by the ex pansion assembly.

According to exemplary embodiments of the invention, the expandable last com prises an expansion assembly and an expandable shell, arranged around the expansion assembly. In this way, the expandable last may combine a localized ex ertion of pressure onto particular portions of the expandable shell via the expansion assembly with a more uniform exertion of pressure onto the insert via the liquid in the liquid chamber. A good compromise between uniform exertion of pressure and localized exertion of pressure may be achieved. Also, the localized exertion of pressure may achieve a pre-shaping of the expandable shell and may thus allow for a particularly good positioning of the insert with respect to the inside of the footwear. Further, the expansion assembly may also provide for core support to the expandable last.

According to a further embodiment, the expansion assembly comprises at least one of a hydraulically operated piston, a pneumatically operated piston, an electrically operate piston, and a spring-loaded piston for exerting the localized pressure. With each of the hydraulically operated piston, the pneumatically operated piston, and the electrically operated piston, an active and highly granular exertion of localized pressure may be possible. With the spring-loaded piston, an external control and power supply may be dispensed with and an effective exertion of loc alized pressure may be achieved with comparably less complexity. In particular, the spring-loaded piston may allow for the expansion assembly to exert localized pressure without a complex interaction between the piston and an external control / power entity. According to a further embodiment, the expansion assembly comprises a base plate, to which said at least one of a hydraulically operated piston, a pneumatically operated piston, an electrically operated piston, and a spring-loaded piston is mounted. In this way, the piston may have a well-defined travel path with respect to the base plate, which in turn may allow for a well-defined travel path with re spect to the footwear. The base plate may allow for a well-defined arrangement / positioning of the expansion assembly within the footwear.

According to a further embodiment, the spring-loaded piston comprises at least one of a coil spring and a gas spring. In particular, the spring-loaded piston may comprise a coil spring or a gas spring.

According to a further embodiment, the expansion assembly is configured to exert localized pressure onto at least one of a toe portion and a heel portion of the expandable shell. In this way, the expansion assembly may be particularly suitable for exerting localized pressure in the front and/or the rear of the expandable shell. This in turn may allow for achieving a good longitudinal positioning, stretching, and/or attaching of the insert to the inside of the footwear. The expansion assembly may thus work similar to a shoe tree and may ensure that the insert is ar ranged over the full length of the inside of the footwear.

According to a further embodiment, the expansion assembly comprises a spring skeleton having a forefoot spring portion, configured to exert localized pressure onto at least one of a toe portion and an instep portion of the expandable shell and having a heel spring portion, configured to exert localized pressure onto a heel portion of the expandable shell. With the spring skeleton, localized pressure may be exerted onto crucial portions of the insert in a particularly effective man ner. The spring skeleton may be an elastic spring structure, ressembling a foot outline / a foot skeleton in its longitudinal direction. The expandable shell may be conformed to some extent to the general shape of a human foot, while leaving ample room for the liquid within the expandable shell to provide for uniform exer tion of pressure onto the expandable shell. Again, a good compromise between uniform exertion of pressure and localized exertion of pressure may be achieved. The spring skeleton may work similar to a shoe tree and may provide a desired stretching of the expandable shell at the toe portion and/or the instep portion and/ or the heel portion of the expandable shell. According to a further embodiment, the spring skeleton is made of metal, in particular made of steel. According to an alternative embodiment, the spring skeleton is made of composite material, in particular made of fiber-reinforced plastics material. The spring skeleton may be made from an elastic synthetic material. It may also be made from a memory alloy or bimetal. It is also possible that the spring skeleton is made from a combination of parts of different materials, in particular from a combination of metal parts and composite material parts. Further, it is possible that pressure exertion pads are provided at the spring skeleton for exerting the localized pressure. The pressure exertion pads may be made from a different material, such as from a plastics material, in particular a plastics material that is softer than the material of the spring skeleton, or from a padding material.

According to a further embodiment, the forefoot spring portion is configured to force its forefoot end portion in a forward and upward direction. In this way, a par ticularly good stretching of the insert and/or a particularly good attachment between the insert and the toe portion of the footwear, which may be difficult due to the irregularities of the inner contour in the toe portion and/or due to the com parably stiff nature of the toe portion of the footwear, may be achieved in an effective manner. The upward component of the force, exerted by the forefoot end portion of the forefoot spring portion, may be particularly effective in achieving an overall strong attachment between the insert and the toe portion of the footwear.

According to a further embodiment, the forefoot spring portion has a waved shaped, with a first exposed portion exerting localized pressure onto the instep portion of the expandable shell and with a second exposed portion exerting local ized pressure onto the toe portion of the expandable shell. The waved shaped of the forefoot spring portion provides for a particular effective way of exerting local ized pressure onto both the toe portion of the expandable shell and the instep portion of the expandable shell. With the waved shape, a balanced exertion of localized pressure between the instep portion and the toe portion of the expand able shell may be achieved. The waved shape may be particularly well-suited for providing localized pressure in the forefoot portion of the expandable last. The second exposed portion may in particular be the forefoot end portion, as described above, and may in particular be configured as being forced in a forward and upward direction.

According to a further embodiment, the forefoot spring portion comprises an in step spring element, extending along the instep portion of the expandable shell and having its free end pointing rearwards. The instep spring element may in particular extend along the instep portion of the expandable shell and may have its free end pointing in a rearward and upward direction. With such a dedicated in step spring element, localized pressure may be exerted particularly well onto the instep portion of the expandable shell. While the instep spring element is seen as part of the forefoot spring portion, it is an element that extends away from that part of the forefoot spring portion that extends between a collar region of the expandable last and the forefoot end portion of the forefoot spring portion. Via this extending away, the instep spring element has a free end pointing rearwards. With the instep spring element having its free end pointing rearwards, the forefoot spring portion may be effectively designed to provide the localized pressure onto the toe portion of the expandable shell and to provide the localized pressure onto the instep portion of the expandable shell in a highly targeted manner, taking into account the particulars of the toe portion and the instep portion in a particularly ef fective manner.

According to a further embodiment, the heel spring portion is configured to force its heel end portion in a rearward and upward direction. In this way, an attach ment between the insert and the heel portion of the footwear, which may be diffi cult due to the particular shape of heel constructions of footwear, may be achieved in an effective manner. In particular, the upward component of the force of the heel end portion towards the expandable shell / towards the insert may be particularly effective in contributing to said attachment.

According to a further embodiment, the expansion assembly comprises a form- stable core support element. The form-stable core support element may in partic ular be substantially L-shaped or substantially T-shaped. The form-stable core support element may provide for enhanced stability for the spring skeleton of the expansion assembly. The form-stable core support element may in particular reach to a sole portion of the expandable shell. It may thus provide an effective positioning of the expandable shell in a downwards portion of the expandable last. In particular, the form-stable core support element may counter potential up ward components of the force exerted by the forefoot end portion and/or the heel end portion of the spring skeleton. It may thus contribute to a multi-directional stretching of the expandable shell.

According to a further embodiment, the expandable last further comprises a lid, to which the expandable shell is mounted. In a particular embodiment, the expan- sion assembly is fixed in position with respect to the lid. For example, the expansion assembly may be mounted to the lid via a mounting rod. In this way, an ef fective positioning of the expansion assembly with respect to the collar of the foot wear may be achieved. Also, core support to the expandable last may be achieved in an effective manner, similar to the core support element, discussed above.

According to a further embodiment, the spring skeleton is mounted to the lid. It is also possible that the spring skeleton is mounted to a core support element, which is in turn mounted to the lid. It is also possible that both the spring skeleton and a core support element are mounted to the lid.

According to a further embodiment, the expansion assembly is attached to the expandable shell. In this case, the expansion assembly may be un-attached to the lid or may be attached to the lid in addition to the attachment to the expandable shell. The attachment between the expansion assembly and the expandable shell may provide for a particularly well-defined exertion of localized pressure by the expansion assembly.

According to a further embodiment, the expandable last further comprises a liquid port, providing liquid communication between the liquid chamber and an external liquid source, wherein the expandable shell is configured to expand for pressing the insert towards an inside of the footwear, when receiving liquid in the liquid chamber via the liquid port. In this way, in addition to the localized pressure exerted by the expansion assembly, the more uniform pressure via the liquid chamber is provided via the reception of liquid from an external liquid source.

According to a further embodiment, the expandable last further comprises a heater arranged in the liquid chamber, wherein the heater is configured to heat liquid in the liquid chamber for expanding the expandable shell and pressing the insert towards an inside of the footwear via an increase in volume of the liquid in the liquid chamber. In this way, in addition to the localized pressure exerted by the expansion assembly, the more uniform pressure via the liquid chamber is provided by an increase in volume of the liquid due to the heating thereof. In this way, the exertion of the more uniform pressure may be achieved without a liquid port and without increasing the amount of liquid in the liquid chamber. According to a further embodiment, the heater is an electric heater. The electric heater may be coupled to an external power supply via a power supply line. The power supply line may run through the lid. It is also possible that the heater comprises a rechargeable power source, such as a rechargeable battery.

According to a further embodiment, the expansion assembly and the heater are fixed in position with respect to each other. In a particular embodiment, the expansion assembly and the heater are formed as an integrated structural unit. In this way, the expandable last may have a high degree of inherent stability and may be handled in a particularly convenient manner.

According to a further embodiment, the expandable last further comprises a lid, to which the expandable shell is mounted. The expansion assembly and/or the heater may also be mounted to the lid. In particular, the expansion assembly and the heater may be mounted to the lid as an integrated structural unit.

According to a further embodiment, the expandable shell and the lid form a liquid- tight enclosure. In particular, the lid and the expandable shell may be free of a liquid port. The lid and the expandable shell being free of a liquid port is to be understood in a way that no liquid communication between the liquid chamber and an outside of the expandable last takes place in the expansion operation, i.e. during the application of pressure to the insert via the expandable shell. The liquid- tight enclosure may keep the amount of liquid within the liquid chamber fixed, and the expansion of the expandable shell may be solely caused by the heating of the liquid within the liquid chamber. This does not exclude the provision of suitable means for filling and evacuating liquid into / from the liquid chamber between such normal operations. For example, the liquid may be exchanged after a certain number of expansion operations, e.g. for cleaning, maintaining the heater, for preventing liquid depositions on the expandable shell, etc.

According to a further embodiment, the expandable last may be combined with an external heater, such as an electric oven or microwave oven. In particular, an embodiment of the invention may be the combination of the expandable last and an external heater, into which the expandable last may be placed together with the footwear. In this way, the expandable last and the footwear may be jointly heated, and the heating action, described above with respect to the heater within the expandable last, may take place as a result of the external heating. The expandable last, having an expansion assembly and an expandable shell, as described with respect to any of the embodiments above, may additionally have any of the following features, alone or in any combination:

The liquid chamber comprises substantially the entire volume between the expansion assembly and the expandable shell.

The expandable shell is elastic, in particular made from latex material.

The expandable shell has, at least in one or more regions thereof, dimension-spe cific elastic properties.

The liquid chamber is at least partly filled with an open-cell foam, in particular with an open-cell polyurethane foam, and/or with a spacer fabric.

The expandable last further comprises at least one expandable liquid bag, arranged outside or inside of the expandable shell.

The expandable last further comprises at least one ancillary liquid port, providing liquid communication between the at least one expandable liquid bag and at least one external liquid source.

The expandable last further comprises at least one ancillary liquid supply line, coupling the at least one expandable liquid bag to the at least one ancillary liquid port, wherein the at least one ancillary liquid supply line in particular runs through the liquid chamber.

The at least one expandable liquid bag comprises at least one of: an expandable liquid bag at an instep portion of the expandable shell; an expandable liquid bag at a toe portion of the expandable shell; an expandable liquid bag in a forefoot portion of the expandable shell; an expandable liquid bag in an upper midfoot portion of the expandable shell.

The at least one expandable liquid bag is at least partly filled with an open-cell foam, in particular with an open-cell polyurethane foam, and/or with a spacer fab ric.

The liquid port is arranged in the lid. The lid has an extension substantially corresponding to a transverse cross-sec tion of the collar of the footwear.

Exemplary embodiments of the invention further include an expandable last for furnishing footwear with an insert, comprising: an expandable shell; a liquid chamber within the expandable shell; and a liquid port, providing liquid communication between the liquid chamber and an external liquid source; wherein the expand able last is insertable into the footwear through a collar of the footwear and wherein, when receiving liquid in the liquid chamber via the liquid port, the expandable shell is configured to expand for pressing the insert towards an inside of the footwear; and wherein the expandable shell has, at least in one or more re gions thereof, dimension-specific elastic properties. Exemplary embodiments of the expandable last, whose expandable shell has dimension-specific elastic properties, provide an alternative tool for effectively furnishing footwear with an insert, as compared to above described exemplary embodiments of expandable lasts. Above described additional features, modifications, and effects are applicable to the expandable last, whose expandable shell has dimension-specific elastic prop erties, in an analogous manner, as long as they are not conceptually excluded by the expandable shell having dimension-specific elastic properties.

With the expandable shell having dimension-specific elastic properties, the course of expansion of the expandable shell can be controlled and a particularly effective exertion of pressure onto the insert may be achieved. For example, the dimen sion-specific elastic properties may allow for the expandable shell to first assume a desired coarse shape, before exerting a highly uniform pressure onto the insert. By having dimension-specific elastic properties, the expandable shell reacts to pressure increases differently in at least two dimensions. The dimensions may be dimensions defined in a cartesian coordinate system or may be dimensions suitably defined in the context of a substantially foot-shaped last, such as a longitud inal dimension of the expandable shell and a circumferential dimension of the ex pandable shell.

According to a further embodiment, the expandable shell has dimension-specific elastic properties in at least one of a midfoot portion and a forefoot portion of the expandable shell. In this way, a particularly good adaptation to the footwear shape may be achieved. Also, a good adaptation to footwear of different sizes may be achieved. In this way, the expandable last may be used for footwear of considerably different sizes.

According to a further embodiment, the expandable shell is configured to expand more easily in a longitudinal dimension than a circumferential dimension in at least one of a midfoot portion and a forefoot portion. In this way, the expandable shell may first expand in the longitudinal dimension, before expanding in the circumferential dimension. This in turn may allow for the expandable last to first cover the full length of the longitudinal dimension of the footwear, before exerting pressure around the circumference of the expandable last. Such a behaviour may help in positioning the insert / keeping the insert in position in a particularly targeted manner, before applying all around pressure. The terminology of the expandable shell being configured to expand more easily in the longitudinal dimen sion than in the circumferential dimension means that the expandable shell ex pands in the longitudinal dimension earlier and/or at a lower fluid pressure than in the circumferential dimension.

According to a further embodiment, the expandable last is free of a form-stable core support element and/or free of an expansion assembly, arranged within the expandable shell. In other words, the exertion of pressure onto the insert may be achieved solely by the provision of an expandable shell with dimension-specific elastic properties and the building-up of pressure within the liquid chamber via liquid received through the liquid port.

The expandable last, having an expandable shell with dimension-specific elastic properties, as described with respect to any of the embodiments above, may ad ditionally have any of the following features, alone or in any combination:

The liquid chamber comprises substantially the entire volume within the expandable shell.

The expandable shell is made from latex material.

The expandable last further comprises at least one expandable liquid bag, ar ranged outside or inside of the expandable shell. The expandable last further comprises at least one ancillary liquid port, providing liquid communication between the at least one expandable liquid bag and at least one external liquid source.

The expandable last further comprises a lid, to which the expandable shell is mounted.

The liquid port is arranged in the lid.

The lid has an extension substantially corresponding to a transverse cross-sec tion of the collar of the footwear.

The expandable last further comprises a heater, configured to heat the liquid in the liquid chamber and/or to heat the expandable shell.

Exemplary embodiments of the invention further include an expandable last for furnishing footwear with an insert, comprising: a rigid last portion; an expandable shell, arranged adjacent to the rigid last portion; a liquid chamber within the ex pandable shell; and a liquid port, providing liquid communication between the liquid chamber and an external liquid source; wherein the expandable last is in- sertable into the footwear through a collar of the footwear and wherein, when receiving liquid in the liquid chamber via the liquid port, the expandable shell is con- figured to expand for pressing the insert towards an inside of the footwear. Exem plary embodiments of the expandable last, having a rigid last portion and an expandable shell adjacent to the rigid last portion, provide an alternative tool for effectively furnishing footwear with an insert, as compared to above described ex- emplary embodiments of expandable lasts. Above described additional features, modifications, and effects are applicable to the expandable last, having a rigid last portion and an expandable shell adjacent to the rigid last portion, in an analogous manner, as long as they are not conceptually excluded by the combination of the rigid last portion and the expandable shell.

According to exemplary embodiments of the invention, the expandable last comprises a rigid last portion and an expandable shell, arranged adjacent to the rigid last portion. The rigid last portion may provide for an effective exertion of pressure in portions of the footwear where good results may be achieved with a rigid struc- ture. In turn, the expandable shell may have smaller extensions and may thus provide the desired highly uniform pressure with a lower amount of liquid. The flexibility of the expandable shell may be combined with the low complexity of a rigid last portion in a beneficial manner. The expandable last may also comprise a plurality of rigid last portions and/or a plurality of expandable shells. The additional features and modifications, as de scribed herein, are applicable to one or a subset or all of the plurality of rigid last portions and/or to one or a subset of all of the plurality of expandable shells. According to a further embodiment, the rigid last portion is made from metal, such as aluminum. Metal may provide for a highly rigid structure of the last portion and may be a good heat conductor, in case the rigid last portion is heated and/or in case the liquid in the liquid chamber is heated. Aluminum provides for a good compromise between the beneficial properties of metal and a comparably low weight. The rigid last portion may also be made from other suitable materials, such as heat resistant plastic.

According to a further embodiment, the rigid last portion is heatable. In this way, the rigid last portion may be used for heating the liquid in the liquid chamber of the expandable last and may thus contribute to the expansion of the expandable shell. Also, the rigid last portion may apply heat to the insert and may thus help in attaching the insert to the inside of the footwear, for example by activating a heat- activated adhesive on the insert. In addition / alternatively, the rigid last portion may be thermally conductive, being configured to conduct heat to the insert from heated liquid in the liquid chamber.

According to a further embodiment, the expandable last comprises a rigid forefoot and instep last portion and a rigid heel last portion, wherein the expandable shell is arranged between the rigid forefoot and instep last portion and the rigid heel last portion. In this way, the expandable last comprises a so-called split last, hav ing a front rigid last portion and a rear rigid last portion. The space between the rigid forefoot and instep last portion and the rigid heel last portion may be partly or substantially entirely filled with the expandable shell, at least when in an expanded state. In this way, a highly uniform pressure may be applied to a midfoot portion and/or ankle portion of the inside of the footwear, while the front and rear rigid last portions exert pressure onto the forefoot portion and the heel portion of the inside of the footwear.

According to a further embodiment, the rigid forefoot and instep last portion and the rigid heel last portion are movable with respect to each other and the expandable last comprises an actuator for controlling a spacing between the rigid forefoot and instep last portion and the rigid heel last portion. In this way, the expandable last may be adapted to the footwear in question, in particular adapted to the shoe size of the footwear in question. Further, the expandable last may be controlled to exert a desired pressure onto the front portion and the heel portion of the inside of the footwear in this manner. Also, the insertion of the expandable last into the footwear may be carried out in a particularly convenient manner, when the rigid forefoot and instep last portion and the rigid heel last portion have a low spacing therebetween. The actuator may be a pneumatic actuator or a hydraulic actuator or an electric actuator.

According to a further embodiment, the expandable last comprises at least one expandable liquid bag, arranged on an outside of the rigid last portion. As discussed above, a localized adaption of the pressure exerted onto the insert towards the inside of the footwear may be achieved in this manner.

According to a further embodiment, the at least one expandable liquid bag com prises at least one expandable liquid bag in a toe region and/or in a heel region of the expandable last, in particular an expandable liquid bag in a toe region of the rigid forefoot and instep last portion of the expandable last. The term toe region may refer to an upper side of the toe region of the expandable last or to a lower side of the toe region of the expandable last or to a joint upper and lower side of the toe region, reaching around the tip of the expandable last.

The expandable last, having a rigid last portion and an expandable shell, ar ranged adjacent to the rigid last portion, as described with respect to any of the embodiments above, may additionally have any of the following features, alone or in any combination:

The liquid chamber comprises substantially the entire volume within the expand able shell.

The expandable shell is elastic, in particular made from latex material.

The liquid port is arranged in the lid. Exemplary embodiments of the invention further include an expandable last for furnishing footwear with an insert, comprising: an expandable shell; a granulate chamber within the expandable shell; and a granulate port, providing a granulate channel between the granulate chamber and an external granulate source; wherein the expandable last is insertable into the footwear through a collar of the footwear and wherein, when receiving granulate in the granulate chamber via the granulate port, the expandable shell is configured to expand for pressing the insert towards an inside of the footwear. The granulate port may in particular be configured for providing a granulate channel between the granulate chamber and an external heated granulate source. Exemplary embodiments of the expandable last, having a granulate chamber within an expendable shell and a granulate port for receiving granulate within the granulate chamber, provide an alternative tool for effectively furnishing footwear with an insert, as compared to above described exemplary embodiments of expandable lasts. Above described additional features, modifications and effects are applicable to the expandable last, having a granulate chamber within an expandable shell, in an analogous manner, as long as they are not conceptually excluded by the combination of the granulate chamber and the expandable shell.

With the granulate chamber within the expandable shell and the granulate port, the expandable last may be conveniently introduced into the interior of the footwear and the expandable shell may exert pressure onto the insert with a high degree of uniformity upon receiving granulate within the granulate chamber. Rely ing on granulate for exerting pressure onto the insert with a high degree of uniformity, the expandable last may work similar to above described expandable lasts, without relying on liquid as the pressure exerting medium. In this way, the footwear may be kept free of damage, in case the expandable shell is punctured or torn during the furnishing of the footwear with an insert, as described herein. Heated granulate, for example received from an external heated granulate source, may help in attaching the insert to the inside of the footwear, for example by activating a heat-activated adhesive on the insert.

The expandable last, having a granulate chamber within an expandable shell, as described with respect to any of the embodiments above, may additionally have any of the following features, alone or in any combination:

The granulate chamber comprises substantially the entire volume within the ex pandable shell. The expandable shell is elastic.

The expandable shell is made from latex material.

The expandable shell is made of synthetic material, in particular of a textile material. The expandable shell may for example by a nylon sock.

The expandable last further comprises at least one ancillary liquid supply line, coupling the at least one expandable liquid bag to the at least one ancillary liquid port, wherein the at least one ancillary liquid supply line in particular runs through the granulate chamber.

The granulate port is arranged in the lid.

The lid has an extension substantially corresponding to a transverse cross-section of the collar of the footwear. The expandable last further comprises a heater, configured to heat the granulate in the granulate chamber and/or to heat the expandable shell.

The expandable last further comprises a form-stable core support element, in particular a substantially L-shaped or substantially T-shaped core support element.

It is also possible that the granulate is introduced into the insert without an inter posed expandable shell. The granulate may be introduced into the insert, before the insert is placed within the footwear and/or when the insert is positioned in the footwear, and an exertion of pressure onto the insert may be achieved via controlling the amount of granulate within the insert and/or the temperature of the granu late.

Exemplary embodiments of the invention further include a method for furnishing footwear with an insert using an expandable last, as described herein. The ex pandable last may be embodied in accordance with any of the embodiments, de scribed above. The additional features, modifications, and effects, described above with respect to the expandable last, apply to the method for furnishing footwear with an insert in an analogous manner.

According to a further embodiment, the insert is a waterproof, breathable bootie. In this way, the method for furnishing footwear with an insert may also be referred to as a method for waterproofing footwear.

Exemplary embodiments of the invention further include a method for furnishing footwear with an insert, the method comprising: inserting an expandable last into the footwear through a collar of the footwear, the expandable last having an expandable shell and a liquid chamber within the expandable shell; and pressing the insert towards an inside of the footwear by expanding the expandable shell via liquid in the liquid chamber. The additional features, modifications, and effects, described above with respect to the expandable last, apply to the method for fur nishing footwear with an insert in an analogous manner. In particular, the expandable last may be embodied in accordance with any of the embodiments described above.

According to a further embodiment, said expanding of the expandable shell via liquid in the liquid chamber comprises introducing liquid into the liquid chamber. In particular, the liquid may be introduced via a liquid port in the expandable last from an external liquid source. Any suitable liquid may be used for expanding the expandable shell. Suitable liquids include water, oils, and thermotransfer fluids, such as 3M Novec 7500 ®.

According to a further embodiment, said expanding of the expandable shell via liquid in the liquid chamber comprises introducing heated liquid into the liquid chamber. In particular, the liquid may be introduced at a temperature between 60°C and 200°C. The temperature may depend on the liquid used. For example, water may be introduced at a temperature of between 60°C and 95°C. The term heated liquid may refer to liquid being warmer than room temperature, in particu lar liquid having at least 30°C.

According to a further embodiment, said expanding of the expandable shell via liquid in the liquid chamber comprises heating the liquid in the liquid chamber. In particular, the liquid may be heated via a heater arranged within the expandable shell.

According to a further embodiment, the inserting of the expandable last into the footwear through a collar of the footwear comprises inserting the expandable last into an inner space of the footwear, after the inner space of the footwear has been closed, e.g. after the footwear has been lasted and the sole has been applied. The inserting of the expandable last into the footwear may take place when the footwear is otherwise fully assembled or substantially fully assembled.

According to a further embodiment, the pressing of the insert towards the inside of the footwear comprises attaching / adhering the insert to the inside of the footwear.

Exemplary embodiments of the invention further include a method for furnishing footwear with an insert, the method comprising: inserting an expandable last into the footwear through a collar of the footwear, the expandable last having an expandable shell and a granulate chamber within the expandable shell; and press ing the insert towards an inside of the footwear by expanding the expandable shell via granulate in the granulate chamber. The additional features, modifica- tions, and effects, described above with respect to the expandable last and with respect to the method for furnishing footwear with an insert by expanding the ex pandable shell via liquid, apply to the method for furnishing footwear with an in sert by expanding the expandable shell via granulate in an analogous manner. In particular, the expandable last may be embodied in accordance with any of the embodiments described above.

It is pointed out that exemplary embodiments of the expandable last, as described herein, may also be used for other purposes than furnishing footwear with an in sert. In particular, the expandable last may also be used at an earlier stage in the production of footwear. For example, the expandable last according to exemplary embodiments of the invention may be used for lasting a shoe upper thereon. The expandable lasts in accordance with the following definitions also form part of the subject matter of the present invention.

Exemplary embodiments of the invention further include an expandable last, com prising: a form-stable core support element; an expandable shell, arranged around the core support element; a liquid chamber within the expandable shell; and a liquid port, providing liquid communication between the liquid chamber and an external liquid source; wherein, when receiving liquid in the liquid chamber via the liquid port, the expandable shell is configured to expand.

Exemplary embodiments of the invention further include an expandable last, comprising: an expansion assembly; an expandable shell, arranged around the expansion assembly; and a liquid chamber within the expandable shell; wherein the expandable shell is configured to expand; and wherein the expansion assembly is configured to adapt its extension for exerting localized pressure onto the expand able shell.

Exemplary embodiments of the invention further include an expandable last, comprising: an expandable shell; a liquid chamber within the expandable shell; and a liquid port, providing liquid communication between the liquid chamber and an ex ternal liquid source; wherein, when receiving liquid in the liquid chamber via the liquid port, the expandable shell is configured to expand; and wherein the ex pandable shell has, at least in one or more regions thereof, dimension-specific elastic properties. Exemplary embodiments of the invention further include an expandable last, com prising: a rigid last portion; an expandable shell, arranged adjacent to the rigid last portion; a liquid chamber within the expandable shell; and a liquid port, pro viding liquid communication between the liquid chamber and an external liquid source; wherein, when receiving liquid in the liquid chamber via the liquid port, the expandable shell is configured to expand.

Exemplary embodiments of the invention further include an expandable last, com prising: an expandable shell; a granulate chamber within the expandable shell; and a granulate port, providing a granulate channel between the granulate chamber and an external granulate source; wherein the expandable last is insertable into the footwear through a collar of the footwear and wherein, when receiving granulate in the granulate chamber via the granulate port, the expandable shell is configured to expand for pressing the insert towards an inside of the footwear.

The additional features, modifications, and effects, described above with respect to exemplary embodiments of the expandable last in the context of furnishing footwear with an insert, apply to the exemplary embodiments of the expandable last of the preceding five paragraphs in an analogous manner.

Further exemplary embodiments of the invention will be described below with ref erence to the accompanying drawings, wherein:

Fig. 1 shows an expandable last in accordance with a first exemplary embodiment of the invention in a longitudinal cross-sectional view;

Fig. 2 shows an expandable last in accordance with a second exemplary embodi ment of the invention in a longitudinal cross-sectional view;

Fig. 3 shows an expandable last in accordance with a third exemplary embodiment of the invention in a longitudinal cross-sectional view;

Fig. 4A shows an expandable last in accordance with a fourth exemplary embodi ment of the invention in a longitudinal cross-sectional view, and Fig. 4B shows a modification thereof in a longitudinal cross-sectional view;

Fig. 5 shows an expandable last in accordance with a fifth exemplary embodiment of the invention in a longitudinal cross-sectional view; Fig. 6 shows an expandable last in accordance with a sixth exemplary embodiment of the invention in a longitudinal cross-sectional view;

Fig. 7 shows an expandable last in accordance with a seventh exemplary embodi ment of the invention in a longitudinal cross-sectional view;

Fig. 8 shows an expandable last in accordance with an eight exemplary embodiment of the invention in a longitudinal cross-sectional view;

Fig. 9 shows an expandable last in accordance with a ninth exemplary embodi ment of the invention in a longitudinal cross-sectional view;

Fig. 10 illustrates a method for furnishing footwear with an insert in accordance with an exemplary embodiment of the invention, the method using an expandable last according to an exemplary embodiment of the invention;

Fig. 11 shows an expandable last in accordance with a tenth exemplary embodi ment of the invention in a longitudinal cross-sectional view;

Fig. 12 shows an expandable last in accordance with an eleventh exemplary embodiment of the invention in a longitudinal cross-sectional view; and

Fig. 13 shows an expandable last in accordance with a twelfth exemplary embodiment of the invention in a longitudinal cross-sectional view.

Fig. 1 shows an expandable last 2 in accordance with a first exemplary embodiment of the invention in a schematic longitudinal cross-sectional view. When ima gining the expandable last 2 arranged in the interior of a footwear and the foot wear being placed on a table or other horizontal structure in its normal use position, the cross-sectional view of Fig. 1 is a vertical cross-sectional view, with the cross-sectional plane running substantially through the center of the expandable last in the transverse direction of the footwear. The expandable last 2 may be used both for a left shoe and a right shoe. However, it is also possible that differ ent versions of the expandable last are used for the left shoe and the right shoe.

The expandable last 2 comprises a form-stable core support element 4. In the ex emplary embodiment of Fig. 1, the core support element 4 is substantially foot- shaped. This means that the core support element 4 roughly resembles a human foot, having an ankle portion, a heel portion, a midfoot portion and a forefoot por tion. In the exemplary embodiment of Fig. 1 , the core support element is flexible, made from rubber material. This means that the core support element 4 has some flexibility, which is particularly useful for inserting the expandable last into the interior of a footwear. In the exemplary embodiment of Fig. 1 , the core support element 4 is made from resilient rubber material, with the resilience of the rubber material counter-acting a deformation and maintaining the foot shape within the footwear. The core support element 4 is considered form-stable, as it does not have any active shape adjusting means. Also, its resilience aims as maintaining the foot shape. Further, while providing some flexibility, the rubber material of the core support element is sufficiently rigid for the expandable last to not completely loose its shape / undergo a substantial shape transformation during insertion into the footwear.

The expandable last 2 further comprises an expandable shell 6. The expandable shell 6 is arranged around the core support element 4. Between the core support element 4 and the expandable shell 6, a liquid chamber 8 is formed. The expandable shell 6 is made from, for example, a latex material and forms the outermost part of the expandable last 2 for a large portion thereof. In particular, the expand able shell 6 forms the outermost portion of the expandable last 2 in the heel portion, the midfoot portion, the forefoot portion, and part of the ankle portion of the expandable last 2. The expandable shell 6 is elastic and can expand upon receiving liquid in the liquid chamber 8.

In the exemplary embodiment of Fig. 1, the expandable shell 6 is liquid-tight / li quid-proof. Upon receiving liquid, such as water, the expandable shell 6 contains the liquid in the liquid chamber 8 and expands as a response to an increasing amount of liquid. The latex material of the expandable shell 6 is inherently liquid- proof, also in an expanded / stretched state. The expandable shell 6 may have one latex layer. It may also be made of a two-layer or three-layer structure, in particular a two-layer latex structure or a three-layer latex structure.

The expandable last 2 further comprises a lid 10. The form-stable core support element 4 and the expandable shell 6 are mounted to the lid 10. Together, the expandable shell 6 and the lid 10 fully enclose the core support element 4 and the liquid chamber 8. The lid 10 is a substantially rotationally symmetric structure, having an inner lid portion 12 and an outer lid portion 14. The lid 10 may be made from plastic or other suitable material. The expandable shell 6 is clamped between the inner lid portion 12 and the outer lid portion 14 in a liquid-tight manner. For additional sealing, a suitable sealing tape, such as a vulcanization tape, may be applied. In this way, no liquid can escape from the liquid chamber 8 through the expandable shell 6 or through its connection to the lid 10. The lid 10 has a transverse cross-sec tional extension that substantially corresponds to the transverse extension of the collar of a footwear. In particular, the transverse extension of the lid 10 may correspond to the transverse extension of the collar of the footwear at or above an ankle portion thereof.

The expandable last 2 further comprises a liquid port 16. In the exemplary embodiment of Fig. 1 , the liquid port 16 is part of the lid 10. In particular, the liquid port 16 is a duct through the inner lid portion 12. In the exemplary embodiment of Fig. 1 , the liquid port 16 is equipped with a valve 18, which allows for liquid to be pressured into the expandable last 2 from an external liquid source and which prevents liquid from flowing back out of the expandable last 2. While generally preventing liquid from flowing out of the liquid chamber 8, the valve 18 may be manipulated in such a manner that the liquid can be evacuated from the liquid chamber 8.

The core support element 4 comprises a liquid supply line system 20 that is coupled to the liquid port 16. Liquid from the external liquid source may enter the liquid supply line system 20 via the liquid port 16. In the exemplary embodiment of Fig. 1 , the liquid supply line system 20 has a substantially vertical liquid supply line, running downwards from the liquid port 16, and a substantially horizontal li quid supply line, running from a sole-side end of the substantially vertical liquid supply line both towards a heel portion of the core support element 4 and a fore foot portion of the core support element 4. The substantially horizontal liquid sup ply line has two openings 22 towards the liquid chamber 8. In particular, the substantially horizontal liquid supply line has an opening 22 towards a heel portion of the liquid chamber 8 and an opening towards a forefoot portion of the liquid chamber 8. In this way, the core support element 4 and its liquid supply line system 20 are well-suited to distribute the liquid, received by the liquid port 16, within the liquid chamber 8. In use, an insert may be arranged around the expandable shell 6, the expandable last 2 and the insert may be jointly introduced into a footwear, an external liquid source may be coupled to the liquid port 16, liquid, in particular heated liquid may be introduced into the liquid chamber 8 via the liquid port 16 and the liquid supply line system 20, the expandable shell 6 may expand as a response to an increasing amount of liquid in the liquid chamber 8, and the insert may be pressed against the inside of the footwear. A more detailed description of the provision of an insert on the inside of the footwear is given below in Fig. 10. It is pointed out that said method steps are exemplary only and that other ways of furnishing footwear with an insert may be implemented with an expandable last in accordance with exemplary embodiments. For example, it is also possible to place an insert into the footwear, to fix an upper portion of the insert to a collar region of the footwear, and to then introduce the expandable last into the joint structure of footwear and insert. When introducing the expandable last into the insert, a cover may be placed over the last to protect the insert and/or the expandable shell from punc turing and to facilitate a smooth insertion of the expandable last into the insert. The cover may be a sock-like structure, in particular a textile sock-like structure. The introduction of liquid and the ensuing steps may then be carried out as described above. It is pointed out that the cover may also be placed over the ex pandable last as an intermediate element between the expandable last and the insert, when the expandable last is used for introducing the insert into the foot wear. In this case, the cover may allow for a smoother pulling of the insert over the expandable last.

Fig. 2 shows an expandable last 2 in accordance with a second exemplary embodiment of the invention in a schematic longitudinal cross-sectional view. Vari ous components of the expandable last 2 of Fig. 2 are identical / similar to the corresponding components of the expandable last 2 of Fig. 1. They are provided with corresponding reference numerals, and reference is made to their description above. The two main differences between the expandable last 2 of Fig. 2 and the expandable last 2 of Fig. 1 are the design of the core support element 4 and the provision of an open-cell foam 24 in the liquid chamber 8. These differences will be discussed in detail below.

The core support element 4 of the expandable last 2 of Fig. 2 is substantially L- shaped. The two legs of the L-shaped core support element 4 are a substantially vertical leg, running from the lid 10 in the direction of the sole of the expandable last 2, and a substantially horizontal leg, running from a sole-side end of the sub- stantially vertical leg towards a forefoot portion of the expandable last 2. The L- shaped core support element is a stiff structure, made from metal or rigid plastics material.

The liquid supply line system 20 of the core support element 4 of Fig. 2 has various branches. In particular, six openings 22 connect the liquid supply line system 20 with the liquid chamber 8. Two of said openings 22 are provided in an ankle portion of the expandable last 2, one is provided in the heel portion of the ex pandable last 2, two are provided in the midfoot portion of the expandable last 2, and one is provided in the forefoot portion of the expandable last 2. A smaller or greater number of openings and branches, providing liquid paths to said openings, are possible as well.

An open-cell foam 24 is arranged around the core support element 4 in the liquid chamber 8. The open-cell foam 24 is a flexible and soft structure that allows for the absorption and passage of liquid. In this way, the open-cell foam may on the one hand absorb liquid and on the other hand pass liquid on towards the expand able shell 6. In the exemplary embodiment of Fig. 2, the open-cell foam is provided in a large portion of the liquid chamber 8. The core support element 4 forms a core / skeleton, around which the open-cell foam 24 is arranged. The open-cell foam 24 provides an initial shape to the expandable shell 6, while allowing for an adaptation of the shape upon receiving liquid in the liquid chamber 8.

Fig. 3 shows an expandable last 2 in accordance with a third exemplary embodiment of the invention in a schematic longitudinal cross-sectional view. Various components of the expandable last 2 of Fig. 3 are identical / similar to the components of the expandable lasts discussed above. They are provided with corres ponding reference numerals, and reference is made to their description above.

In the exemplary embodiment of Fig. 3, the core support element 4 is substan tially T-shaped, having a substantially vertical leg and a substantially horizontal cross-bar / cross plate, extending from the substantially vertical leg both towards the heel portion of the expandable last 2 and towards the forefoot portion of the expandable last 2. It is also possible that the core support element has two substantially vertical legs and a substantially horizontal cross bar / cross plate, attached to both substantially vertical legs. In this case, the core support element would be substantially U-shaped, in particular in the form of an upside down U. In the exemplary embodiment of Fig. 3, the core support element 4 is free of a liquid supply line system. Instead, the liquid port 16 is directly coupled to the liquid chamber 8. Liquid from the external liquid source is directly supplied to the liquid chamber 8, without flowing through the core support element 4.

The expandable last 2 of Fig. 3 further comprises an expandable liquid bag 26, arranged on the outside of the expandable shell 6 at an instep portion of the expandable shell 6. The expandable last 2 of Fig. 3 further comprises an ancillary liquid port 28, which is coupled to the expandable liquid bag 26 via an ancillary li quid supply line 30. The ancillary liquid port 28 is equipped with a valve 32. The ancillary liquid supply line 30 runs through the interior of the expandable shell 6, i.e. through the liquid chamber 8. Alternatively, the ancillary liquid supply line may run along the outside of the expandable shell 6. The ancillary liquid supply line 30 may be a flexible liquid supply line, such as a rubber hose type liquid line.

The expandable liquid bag 26 is made from elastic material, such as from latex material, and may expand upon receiving liquid via the ancillary liquid port 28 and the ancillary liquid supply line 30. The liquid port 16 and the ancillary liquid port 28 allow for controlling the pressure in the liquid chamber 8 and the pressure in the expandable liquid bag 26 to differ from each other, such that controlled pressure differences between the instep portion of the expandable last 2 and the re mainder of the expandable last 2 may be achieved. The liquid port 16 and the ancillary liquid port 28 may be coupled to different external liquid sources. In addi tion / alternatively, other means for achieving a desired pressure differential between the liquid chamber 8 and the expandable liquid bag 26, such as different valves in the liquid port 16 and the ancillary liquid port 28, may also be provided.

In the exemplary embodiment of Fig. 3, a spacer fabric 34 is arranged in the ex pandable liquid bag 26. The spacer fabric 34 may provide for an initial shape of the expandable liquid bag 26, while allowing liquid to pass therethrough and dis tributing within the expandable liquid bag 26.

Fig. 4A shows an expandable last 2 in accordance with a fourth exemplary em bodiment of the invention in a schematic longitudinal cross-sectional view. Various components of the expandable last 2 of Fig. 4A are identical / similar to the components of the expandable lasts discussed above. They are provided with corresponding reference numerals, and reference is made to their description above. The expandable last 2 of Fig. 4A is somewhat similar to the expandable last of Fig. 1. The expandable last 2 of Fig. 4A also comprises a substantially footshaped, form-stable core support element 4. The core support element 4 is some what shorter in a forefoot portion of the expandable shell and has a substantially flat front end portion. Instead of an opening towards the front of the core support element, the liquid supply line system 20 of the core support element 4 of Fig. 4A has transverse openings 22 close to its front end, as indicated by a circle in Fig. 4 A.

The expandable last 2 of Fig. 4A further comprises an expandable liquid bag 26, arranged within the expandable shell 6 and arranged between the front end of the core support element 4 and the toe end of the expandable shell 6. In particular, the expandable liquid bag is arranged to abut the front end of the core support element 4. The expandable liquid bag 26 is in liquid communication with an ancil lary liquid port 28 via an ancillary liquid supply line 30. In the exemplary embodiment of Fig. 4A, the ancillary liquid supply line 30 at least partly runs through the core support element 4. The expandable liquid bag 26 is arranged and configured to expand upon receiving liquid from an external liquid source via the ancillary liquid port 28 and the ancillary liquid supply line 30. Further, the expandable liquid bag 26 is arranged and configured to expand towards the front of the expandable last, i.e. towards the front of the expandable shell 6, as indicated in broken lines in Fig. 4A. In particular, the expandable liquid bag 26 may expand to abut the expandable shell 6 in operation. In this way, the expandable liquid bag 26 may exert pressure onto the toe portion of the insert in a particularly targeted manner. The liquid in the expandable liquid bag 26 may exert pressure onto the toe portion in a highly reliable manner and cannot evade the toe region, irrespective of the overall circumstances within the footwear. The pressure within the expandable liquid bag 26 may be chosen to be the same or similar to the pressure within the liquid chamber 8 in operation. It is also possible that the pressure within the expandable liquid bag 26 is greater than the pressure within the liquid chamber 8.

Fig. 4B shows an expandable last 2 in accordance with a modification of the ex pandable last 2 of Fig. 4A. The expandable last 2 of Fig. 4B is also in accordance with an exemplary embodiment of the invention and is also depicted in a schematic longitudinal cross-sectional view.

In the exemplary embodiment of Fig. 4B, the core support element 4 and the ex pandable liquid bag 26 in the forefoot portion of the expandable shell 6 do not abut along a flat surface, but along a contoured surface. In particular, the core support element 4 extends further to the front of the expandable last 2 in an upper portion thereof, as compared to a lower portion thereof. In this way, the ex pandable liquid bag is restrained from expanding towards the top, at least to some extent, and an expansion towards the front of the expandable shell 6 is pro moted.

Further, a directing element 36, such as a knitted fabric, is provided on the sole side of a front portion of the core support element 4 and on the sole side of the expandable liquid bag 26. The directing element 36 may have the double purpose of holding the sole side of the expandable liquid bag 26 in position with respect to the core support element 4 and of preventing the expandable liquid bag 26 to ex pand towards the sole side of the expandable shell 6. The contoured engagement surface between the core support element 4 and the expandable liquid bag 26 and the directing element 36 may cooperate to promote the expansion of the expandable liquid bag 26 towards the front of the expandable last 2. The expand able liquid bag 26 may be molded or welded to the core support element 4 or may be attached thereto in any other suitable manner. Also, the directing element 36 may be molded or welded to the core support element 4 and/or to the expandable liquid bag 26. It is also possible that the directing element 36 may be integrated with the expandable liquid bag 26 and/or the core support element 4. For ex ample, the expandable liquid bag 26 and/or the core support element may be molded onto the directing element 36. In that case, the directing element may be partly or fully arranged in the expandable liquid bag 26 and/or the core support element. The directing element 36 may for example be made from PE, PES, or PA.

The expandable liquid bag 26 in the forefoot portion of the expandable shell 6 may be made from any suitable material that is expandable and that can be coupled to the directing element 36. The expandable liquid bag 26 in the forefoot portion of the expandable shell 6 may be made from a bladder structure that has an inherent 3D shape. The expandable liquid bag may for example be made from latex or thermoplastic or adherable plastic compounds, such as Butyl.

Yet further, the expandable last comprises an expandable liquid bag 26 in an upper midfoot portion of the expandable shell 6. The expandable liquid bag 26 is coupled to an external liquid source via a further ancillary liquid port 28 and a fur ther ancillary liquid supply line 30. The expandable liquid bag 26 in the upper mid- foot portion of the expandable shell 6 may be partly or entirely filled with a spacer fabric or may be not filled with a spacer fabric. The expandable liquid bag 26 in the upper midfoot portion of the expandable shell 6 contributes to the exertion of suitable pressure onto an instep portion of the insert via the instep portion of the expandable shell 6.

Fig. 5 shows an expandable last 2 in accordance with a fifth exemplary embodiment of the invention in a schematic longitudinal cross-sectional view. Various components of the expandable last 2 of Fig. 5 are identical / similar to the components of the expandable lasts discussed above. They are provided with corres ponding reference numerals, and reference is made to their description above.

As compared to the expandable lasts of Figs. 1 to 4, the expandable last 2 of Fig. 5 has an expansion assembly 40, which will be described in detail below. In the exemplary embodiment of Fig. 5, the liquid port 16 is directly coupled to the liquid chamber 8, such that the liquid from the external liquid source is directly supplied into the liquid chamber 8.

The expansion assembly 40 comprises a base plate 42 and a spring-loaded piston 44. The base plate 42 is oriented substantially horizontally and is arranged on the inside of the expandable shell 6 at a sole portion thereof. In the exemplary embodiment of Fig. 5, the base plate 42 extends over about 50% of the sole area of the expandable last 2. The spring-loaded piston 44 is attached to the base plate 42 and is also oriented substantially horizontally. The spring-loaded piston is arranged to stretch the expandable shell 6 in a longitudinal direction of the ex pandable last 2 and to exert localized pressure onto the expandable shell 6 in a heel portion and toe portion of the expandable last 2. With the localized pressure stemming from the spring of the spring-loaded piston 44, no active means, i.e. no means relying on an external supply of energy, are required for exerting the local ized pressure. The localized pressure is solely generated by the spring of the spring-loaded piston 44, acting against its compression.

The expansion assembly 40 further comprises a mounting rod 54, which is coupled to the lid 10. Via the mounting rod 54, the expansion assembly 40 is fixed in position with respect to the lid 10. An overall stable arrangement may be achieved, and the expansion assembly may provide core support to the expand able last 2, similar to the core support element 4 described above. The expandable last 2 of Fig. 5 allows for providing localized pressure at selected portions of the expandable last 2, while providing a more uniform all around pressure via the liquid in the liquid chamber 8. In this way, different pressure levels and/or a dynamic application of different pressures at different times may be achieved in an effective manner.

Fig. 6 shows an expandable last 2 in accordance with a sixth exemplary embodiment of the invention in a schematic longitudinal cross-sectional view. Various components of the expandable last 2 of Fig. 6 are identical / similar to the components of the expandable lasts discussed above. They are provided with corresponding reference numerals, and reference is made to their description above.

The expandable last 2 of Fig. 6 is somewhat similar to the expandable last 2 of Fig. 5. Flowever, the expansion assembly 40 differs considerably from the expansion assembly 40 from Fig. 5. In particular, instead of the spring-loaded piston 44, an active piston 46 is provided. In the exemplary embodiment of Fig. 6, the active piston 46 is a pneumatically operated piston 46. Similar to the spring-loaded piston 44 of Fig. 5, the pneumatically operated piston 46 exerts localized pressure onto the heel portion and the toe portion of the expandable shell 6.

The expansion assembly 40 comprises a pneumatic port 48 in the lid 10 and a pneumatic line 50, connecting the pneumatic port 48 and the pneumatically oper ated piston 46. The pneumatic port 48 has a valve 52. In operation, the extension of the pneumatically operated piston 46 can be controlled via the pneumatic pressure therein, which in turn may be controlled via an external gas source, such as an external air source, coupled to the pneumatic port 48. In this way, the exertion of localized pressure can be controlled with a high degree of granularity.

The expansion assembly 40 of Fig. 6 also comprises a mounting rod 54. Via the mounting rod 54, the base plate 42 and the pneumatically operated piston 46 are fixed in position with respect to the lid 10. In this way, the expansion assembly 40 has high positional stability within the expandable last 2, and the expandable last 2 can be handled conveniently as an overall highly stable structure.

Fig. 7 shows an expandable last 2 in accordance with a seventh exemplary em bodiment of the invention in a schematic longitudinal cross-sectional view. Various components of the expandable last 2 of Fig. 7 are identical / similar to the components of the expandable lasts discussed above. They are provided with corresponding reference numerals, and reference is made to their description above.

The expandable last 2 of Fig. 7 is somewhat similar to the expandable last 2 of Fig. 5, albeit with some significant differences. The expandable last 2 of Fig. 7 also has an expansion assembly 40, which comprises a base plate 42 and a spring-loaded piston 44. The expansion assembly 40 further comprises a mounting rod 54, which is mounted to the lid 10 and to which the base plate 42 is mounted. The spring-loaded piston 44 is in turn mounted to the base plate 42. In this way, the spring-loaded piston 44, the base plate 42, the mounting rod 54, and the lid 10 are fixed in position with respect to each other. In this arrangement, the spring-loaded piston 44 exerts localized pressure onto the expandable shell 6 at a single portion thereof. In the exemplary embodiment of Fig. 7, the spring-loaded piston 44 exerts localized pressure onto the toe portion of the expandable shell 6.

The expandable last 2 of Fig. 7 further comprises a heater 60. In the exemplary embodiment of Fig. 7, the heater 60 is embodied as an electric heater. In particular, the heater is embodied as a heating coil that is wound around the mounting rod 54. The heater 60 is coupled to a power supply cable 62 that runs through the lid 16 and that may be coupled to an external power source, such as a power adapter that is in turn connectable to a standard power outlet. Via the heater, the liquid in the liquid chamber 8 may be heated and expanded. The expansion of the liquid may be used for the expansion of the expandable shell 6. In this way, in addition to the localized pressure exerted by the expansion assembly 40, a highly uniform pressure may be generated all around the expandable shell 6.

In the exemplary embodiment of Fig. 7, both the lid 10 as well as the expandable shell 6 are free of a liquid port. When being arranged within the footwear and ex erting pressure onto the insert towards the inside of the footwear, no liquid is added or evacuated from the liquid chamber 8. The heating of the liquid within the liquid chamber 8 provides for the all around exertion of pressure onto the insert. It is pointed out that any suitable liquid may be used for achieving the expansion of the expandable shell 6. For example, the liquid chamber 8 may be filled with water, and the expansion of the water upon heating may provide for the desired increase in pressure.

It is pointed out that, instead of / in addition to a heater being provided in the liquid chamber 8, the expandable last may be placed into a heating device, such as an electric oven or a microwave oven, and may then be inserted into the foot wear. This heating may also achieve the expansion of the liquid in the liquid chamber 8, and the exertion of pressure onto the insert via the expandable shell 6 may take place via the heated liquid.

Fig. 8 shows an expandable last 2 in accordance with an eighth exemplary embodiment of the invention in a schematic longitudinal cross-sectional view. Vari ous components of the expandable last 2 of Fig. 8 are identical / similar to the components of the expandable lasts discussed above. They are provided with corresponding reference numerals, and reference is made to their description above.

The expandable last 2 of Fig. 8 is somewhat similar to the expandable last 2 of Fig. 5, albeit with some significant differences. The expandable last 2 of Fig. 8 does not have a core support element nor an expansion assembly nor a heater, as described with respect to Figs. 1 to 7. However, the expandable last 2 of Fig. 8 has a liquid port 16, running through the lid 10, for inserting liquid into the liquid chamber 8. The expandable shell 6 expands solely in response to the introduction of liquid into the liquid chamber 8.

The expandable shell 6 has dimension-specific elastic properties. In the exemplary embodiment of Fig. 8, a midfoot portion 70 of the expandable shell 6 has dimension-specific elastic properties. It is possible that other portions of the ex pandable shell 6 have dimension-specific elastic properties as well.

In particular, the midfoot portion 70 of the expandable shell 6 stretches in a longit udinal dimension 72 at a lower liquid pressure than in a circumferential dimension 74. In this context, the circumferential dimension 74 is defined as extending around the tube-like cross-section of the midfoot portion 70. With the expandable shell 6 thus expanding easier in the longitudinal dimension 72 than in the circum ferential dimension 74 in the midfoot portion 70, an increase in liquid pressure leads to an elongation of the midfoot portion 70 along the length of the expandable last 2, before a circumferential expansion and, thus, an increase in cross- section in the midfoot portion 70 takes place. In this way, the expandable last 2 may first adapt to a particular footwear size / length, before exerting a highly uniform all around pressure onto the insert against the inside of the footwear. In a particular exemplary embodiment, the length of the midfoot portion may extend by between 10% and 30%, in particular by about 20%, before the circumferential expansion takes place.

Fig. 9 shows an expandable last 2 in accordance with a ninth exemplary embodi ment of the invention in a schematic longitudinal cross-sectional view. Various components of the expandable last 2 of Fig. 9 are identical / similar to the com ponents of the expandable lasts discussed above. They are provided with corresponding reference numerals, and reference is made to their description above.

The expandable last 2 of Fig. 9 comprises a rigid forefoot and instep last portion 80 and a rigid heel last portion 82. The rigid forefoot and instep last portion 80 and the rigid heel last portion 82 are made from aluminum. Jointly, they form a split last, having a rigid front portion and rigid rear portion. Both the rigid forefoot and instep last portion 80 and the rigid heel last portion 82 are heatable. They are coupled with a front power supply line 81 and a read power supply line 83, respectively, via which internal heaters of the rigid forefoot and instep last portion 80 and the rigid heel last portion 82 may be provided with electric energy. The in ternal heaters may be induction heaters or may comprise heating cartridges or may comprise other suitable heating devices. It is also possible that the rigid fore foot and instep last portion 80 and the rigid heel last portion 82 are not heatable. They may still be thermally conductive, and the lines 81 , 83 may be sensor lines, coupling temperature sensors within the rigid forefoot and instep last portion 80 and the rigid heel last portion 82 to a control unit.

The rigid forefoot and instep last portion 80 and the rigid heel last portion 82 are movable with respect to each other. The expandable last 2 comprises a pneu matic actuator 84, which is configured to control a spacing between the rigid forefoot and instep last portion 80 and the rigid heel last portion 82. The expandable last 2 further comprises a first gas port 86, equipped with a valve 88, and a second gas port 90, equipped with a valve 92. The first gas port 86 and the second gas port 88 are coupled to the pneumatic actuator 84 via a first gas line 94 and a second gas line 96, respectively. The first gas port 86 and the second gas port 90 are configured to introduce gas into the pneumatic actuator 84 from an external gas source and to release gas from the pneumatic actuator 84, re spectively. By an according control of the first gas port 86 and the second gas port 90, the pressure in the pneumatic actuator 84 and, thus, the spacing between the rigid forefoot and instep last portion 80 and the rigid heel last portion 82 may be controlled in a highly accurate manner. The split last may thus be adapted to different footwear sizes / lengths over a wide size / length range.

The expandable last 2 further comprises an expandable shell 6, which has a li quid chamber 8 therein. The expandable last 2 further comprises a liquid port 16, having a valve 18, which is coupled to the liquid chamber 8 via a liquid supply line 20. In operation, liquid may be received in the liquid chamber 8, and the expandable shell 6 may exert a highly uniform pressure onto an insert on the inside of the footwear in those portions of the footwear that are between the rigid forefoot and instep last portion 80 and the rigid heel last portion 82.

The expandable last 2 further comprises an expandable liquid bag 26, arranged around the toe portion of the rigid forefoot and instep last portion 80. The liquid chamber 8 and the expandable liquid bag 26 are coupled via an ancillary liquid supply line 30. The ancillary liquid supply line 30 extends through the rigid forefoot and instep last portion 80. With the expandable liquid bag 26, the pressure exerted onto the insert in a forefoot portion of the footwear may be made more uniform than with the rigid forefoot and instep last portion 80. The expandable li quid bag may balance out sharp contours of the inside of the footwear in the toe portion in a particularly effective manner.

With the combination of the rigid forefoot and instep last portion 80 and the rigid heel last portion 82 on the one hand and the expandable shell 6 and the expandable liquid bag 26 on the other hand, a good compromise between using rigid, comparably straightforward to implement last portions and using expandable last portions, which are highly flexible and well-suited for applying a uniform pressure, may be achieved.

Fig. 10 illustrates a method for furnishing footwear 110 with an insert 100 in accordance with an exemplary embodiment of the invention. The method makes use of an expandable last 2 in accordance with an exemplary embodiment of the invention. In the exemplary illustration of Fig. 10, the expandable last 2 corresponds to the expandable last 2 of Fig. 5. However, it is stressed that an expand able last in accordance with any of the embodiments, as described herein, may be used.

Fig. 10A depicts the expandable last 2 and an insert 100. The insert 100 is ar ranged over the expandable last 2. The insert 100 is in a relaxed state, i.e. in a state unstretched by the expandable last 2. In the illustration of Fig. 10, the insert 100 is a waterproof, breathable bootie. Accordingly, the method illustrated in Fig. 10 is a method for waterproofing footwear. The waterproof, breathable bootie may for example be embodied in accordance with any of the embodiments, as described in PCT/EP2017/068030 and/or PCT/EP2018/084179.

The insert 100 comprises a first glue-covered area 102 around the toe portion of the insert 100, a second glue-covered area 104 around the heel portion of the insert 100, and a third glue-covered area 106 along the collar of the insert 100. In the exemplary embodiment of Fig. 10, all of the first glue-covered area 102, the second glue-covered area 104, and the third glue-covered area are provided with heat-activated adhesive. Instead of / in addition to the third glue-covered area 106, a textile tape, sewn to the insert 100 and provided with suitable adhesive, may be provided.

Fig. 10B depicts the expandable last 2 and the insert 100 inserted into the interior of the footwear 110. In the illustrated embodiment of Fig. 10, the footwear 110 is a low shoe. When introducing the expandable last, the insert 100 is placed onto the sole portion of the interior of the footwear 110 and against the heel portion of the interior of the footwear 110. With the expandable last 2 being in an unexpanded state and the insert 100 being in a relaxed state, the insert 100 is spaced from the other portions of the inside of the footwear 110.

Fig. 10C depicts the expandable last 2 with the spring-loaded piston 44 having a larger horizontal extension than in Fig. 10B. The change in extension is the result of the spring of the spring-loaded piston counter-acting its compression and exerting localized pressure onto the toe portion and the heel portion of the expandable shell 6. The change in extension may be triggered by a release mechanism. For example, the spring-loaded piston may have a release button, which may be operated / pushed by an operator. For example, the release button may be operated manually, either through the footwear 110, the insert 100 and the expandable shell 6 or through the expandable shell 6 only or via a suitable mechanism at the lid 10. It is also possible that the spring-loaded piston expands without a release mechanism. For example, the spring-loaded piston may continuously force its extension, when being inserted into the footwear, similar to a shoe tree. It is further possible that the introduction of liquid causes the spring-loaded piston to expand or that the change in extension is triggered in any other suitable manner. Fig. 10D depicts the expandable last 2 with an external liquid supply line 120 coupled to the liquid port 16 of the expandable last 2. Via the liquid port 16, water is introduced into the liquid chamber 8 of the expandable last 2. In the exemplary embodiment of Fig. 10, the water is introduced into the liquid chamber 8 with a temperature of between 60°C and 98°C, in particular with a temperature of about 95°C. Also, water is introduced until a target liquid pressure is reached in the liquid chamber 8. The target liquid pressure may be between 0.1 bar and 2 bar, in particular about 0.2 bar. As a result, the insert 100 is pressed against the inside of the footwear 110. The water provides for a uniform pressure within the liquid chamber 8 and presses the insert 100 towards the inside of the footwear 110 in a highly uniform manner. The temperature of the water also activates the heat- activated adhesive in the first, second, and third glue-covered areas 102, 104, 106. It is understood that the temperature and pressure of the liquid may be se lected, depending on the particular liquid used. Various types of heat-activated adhesives may be activated at temperatures between 60°C and 200°C, and the liquid may be introduced at a temperature suitable for the adhesive in question. An example for a suitable adhesive is temperature re-activatable PU, such as Irotex from P.B. Fuller.

Fig. 10E depicts the expandable last 2 with the external liquid supply line 120 de coupled from the liquid port 16.

Fig. 10F additionally depicts a toe cap protector 130, put over the toe portion of the footwear 110. The toe cap protector 130 may be held in place by a rubber band, being wrapped around the heel of the footwear 110. In this way, a counterpressure may be provided at the toe portion of the footwear 110 and the toe portion of the footwear 110 may be protected.

Fig. 10G depicts the expandable last 2, the insert 100, the footwear 110, and the toe cap protector 130 loosely placed in a bag 138. The bag 138 in turn is placed in a pressure chamber 140. The pressure chamber 140 is coupled to a pressure line 142, through which pressurized air can flow into the pressure chamber 140.

Fig. 10H depicts the situation, after pressurized air has flown into the pressure chamber 140. In the exemplary embodiment of Fig. 10, an air pressure of between 2 bar and 7 bar, in particular an air pressure of about 5.5 bar, is used for pressurizing the pressure chamber 142. The pressurized air presses the bag 138 against the footwear 110 and provides for a counter-pressure against the expandable last 2.

The combination of water pressure in the expandable last 2, heat from the water in the expandable last 2, and air pressure in the pressure chamber 140 are a highly effective way for adhering the insert 100 to the inside of the footwear 110. A very stable attachment with a highly uniform adhesion across the first, second, and third glue-covered areas 102, 104, 106 may be achieved.

Fig. 11 shows an expandable last 2 in accordance with a tenth exemplary embodiment of the invention of a schematic longitudinal cross-sectional view. Various components of the expandable last 2 of Fig. 11 are identical / similar to the com ponents of the expandable lasts discussed above. They are provided with corresponding reference numerals, and reference is made to their description above.

The expandable last 2 of Fig. 11 is somewhat similar to the expandable last 2 of Fig. 5. In particular, the expandable last 2 of Fig. 11 also has an expansion assembly 40 and also has a liquid port 16 that is directly coupled to the liquid chamber 8. However, the expansion assembly 40 of the expandable last 2 of Fig. 11 is quite different from the expansion assembly 40 of the expandable last 2 of Fig. 5, as will be laid out below.

The expansion assembly 40 of the expandable last 2 of Fig. 11 has a form-stable core support element 4. The core support element 4 is substantially T-shaped. In particular, the core support element 4 has the design of the core support element 4 described above with respect to Fig. 3. Instead of being viewed as a T-shaped core support element, the core support element 4 may also be seen as the combination of a base plate and a mounting rod, attaching the base plate to the lid 10, as described above with respect to Fig. 5. The properties described above with respect to various embodiments of the core support element and described above with respect to various embodiments of the combination of the base plate and the mounting rod may be implemented in the framework of the expansion as sembly 40 of the expandable last 2 of Fig. 11 in an analogous manner.

In the exemplary embodiment of Fig. 11 , the expansion assembly 40 comprises a spring skeleton 55. The spring skeleton 55 is fixed to the lid 10 and extends towards a forefoot portion of the expandable last 2 and towards a heel portion of the expandable last 2 from the lid 10. In particular, the spring skeleton 55 has a forefoot spring portion 56 and a heel spring portion 57. Both the forefoot spring portion 56 and the heel spring portion 57 are configured to exert localized pressure onto the expandable shell 6 of the expandable last 2.

The forefoot spring portion 56 has a waved shape. In particular, the forefoot spring portion 56 has a first exposed portion 56a and a second exposed portion 56b. The first exposed portion 56a is located at an instep portion of the expandable last 2. The second exposed portion 56b is located at a toe portion of the ex pandable last 2. The first and second exposed portion 56a, 56b may be thought of as high portions of the waved shape of the forefoot spring portion 56, when fitting a straight line through the waved shape of the forefoot spring portion 56.

The forefoot spring portion 56 further comprises a pressure exertion pad 56c. The pressure exertion pad 56c is arranged at the forefoot end portion of the forefoot spring portion 56.

The heel spring portion 57 extends from the lid 10 towards a heel portion of the expandable last 2. The heel spring portion 57 has a pressure exertion pad 57a at the heel end portion of the heel spring portion 57.

The forefoot spring portion 56 and the heel spring portion 57 are of a metal strip design. In the longitudinal direction of the expandable last 2, the forefoot spring portion 56 has the described waved shape from the lid 10 to the toe portion of the expandable last 2, and the heel spring portion 57 has the depicted curved shape from the lid 10 to the heel portion of the expandable last 2. In the transverse dir ection of the expandable last 2, i.e. in the direction orthogonal to the viewing plane of Fig. 11, both the forefoot spring portion 56 and the heel spring portion 57 have a substantially constant width, thus forming a metal strip between the toe portion of the expandable last 2 and the heel portion of the expandable last 2. The forefoot spring portion 56 and the heel spring portion 57 may in particular be made of a metal strip having a width between 1 cm and 3 cm, in particular a width of between 1 cm and 2 cm.

In the exemplary embodiment of Fig. 11 , the forefoot spring portion 56 and the heel spring portion 57 are made from a continuous metal strip, i.e. they are provided as an integrated one-piece structure. However, it is also possible that the forefoot spring portion 56 and the heel spring portion 57 are separate ele- ments, with each of these separate elements being mounted to the lid 10 or to the core support element 4.

An exception to the constant width of the forefoot spring portion 56 and the heel spring portion 57 are the pressure exertion pad 56c at the toe portion of the fore foot spring portion 56 and the pressure exertion pad 57a the heel portion of the heel spring portion 57. The pressure exertion pads 56c, 57a have a wider exten sion than the forefoot spring portion 56 and the heel spring portion 57, thus providing for a somewhat more extended application of pressure onto the ex pandable shell 6.

The spring action of the spring skeleton 55 is described as follows. Both the forefoot spring portion 56 and the heel spring portion 57 are configured to exert a spring force that pushes the forefoot spring portion 56 and the heel spring portion 57 upwards in the expandable last 2.

In this context, the term upwards corresponds to the upwards direction in the viewing plane of Fig. 11, which also corresponds to the upwards direction of the footwear, when oriented in the normal use position. This upwards directed spring force is illustrated in Fig. 11 by the spring skeleton 55 being shown in two different positions / states. In particular, the spring skeleton 55 is on the one hand shown in phantom, with said position / state representing a potential positon / state directly after insertion of the expandable last 2 into a footwear. In this position / state, the forefoot spring portion 56 and the heel spring portion 57 are biased downwards, and the forefoot spring portion 56 and the heel spring portion 57 exert an upwards directed force. This upwards directed force pushes / forces the spring skeleton 55 in the second depicted position / state, being shown in solid lines. In this positon / state, the first exposed portion 56a exerts localized pressure onto the instep portion of the expandable shell 6, the second exposed por tion 56b exerts localized pressure onto the toe portion of the expandable shell 6, and the heel end portion of the heel spring portion 57 exerts localized pressure onto the heel portion of the expandable shell 6. The first exposed portion 56a, which is roughly in the middle between the lid 10 and the toe end portion of the forefoot spring portion 56, exerts localized pressure in a substantially upward dir ection. The second exposed portion 56b which is a toe end portion of the forefoot spring portion 56, exerts localized pressure in a forward and upward direction. The heel end portion of the heel spring portion 57 exerts localized pressure in a rearward and upward direction. With the spring skeleton 55 of the expandable last 2 of Fig. 11 , localized pressure may be exerted at particularly crucial portions, namely at the instep portion, the toe portion and the heel portion, with the particular directions of pressure being particularly effective for the attachment of the insert. The expansion assembly 40 of the expandable last 2 of Fig. 11 co-operates very well with the more uniform application of pressure via liquid introduced into the expandable shell 6 via the liquid port 16.

It has been described that the spring skeleton 55 and the core support element 4 are jointly viewed as an expansion assembly. However, one can also view the spring skeleton 55 as an additional element that supplements the core support element 4. In particular, the core support element 4 may be embodied in any of the variations described above with respect to Figs. 1 to 4, and the spring skel eton may be added thereto for exertion of localized pressure.

Fig. 12 shows an expandable last 2 in accordance with an eleventh exemplary embodiment of the invention in a schematic longitudinal cross-sectional view. Various components of the expandable last 2 of Fig. 12 are identical / similar to the components of the expendable last discussed above. They are provided with corresponding reference numerals, and reference is made to their description above.

The expandable last 2 of Fig. 12 is somewhat similar to the expandable last 2 of Fig. 11. In particular, the expandable last 2 of Fig. 12 also comprises an expan sion assembly 40 that has a spring skeleton 55. In the exemplary embodiment of Fig. 12, the expandable last 40 does not have a core support element. However, the expandable last 40 of Fig. 12 may be additionally provided with a core support element, as described herein.

The spring skeleton 55 of the expandable last 2 of Fig. 12 also has a forefoot spring portion 56 and a heel spring portion 57. The heel spring portion 57 is em bodied in the same manner as the heel spring portion 57 of the spring skeleton 55 of Fig. 11. Reference is made to its description above.

In the exemplary embodiment of Fig. 12, the forefoot spring portion 56 is substan tially L-shaped from the lid 10 to its toe end portion. This substantially L-shaped structure may be ridged, as depicted in Fig. 12, or may exert an upwards spring force, as described with respect to the forefoot spring portion 56 of Fig. 11. The forefoot spring portion 56 of Fig. 12 comprises an instep spring element 58 that extends along the instep portion of the expandable shell 6. In particular, the instep spring element 58 extends from close to the toe portion of the described substantially L-shaped structure in an upward and rearward direction. The terms upward and rearward refer to the depicted orientation of Fig. 12, which corresponds to the orientation of the expandable last 2 when inserted into a footwear in its nor mal use orientation. It can also be said that the instep spring element 58 has its free end pointing in a rearward and upward direction.

The instep spring element 58 is configured to exert localized pressure onto the in step portion of the expandable shell 6. For illustration, the instep spring element 58 is shown in two states / positions. On the one hand, the instep spring element 58 is shown in phantom, which may correspond to a positon / state directly after insertion of the expandable last 2 into the footwear. When in said positon / state, a spring action of the instep spring element 58 forces the instep spring element 58 upwards. This spring action leads to the instep spring element 58 being forced upwards and exerting localized pressure onto the instep portion of the expandable shell 6. Said pressure exertion position / state is shown in a solid line in Fig. 12.

The expandable last 2 of Fig. 12 has similar properties as the expandable last 2 of Fig. 11. In particular, both rely on a spring skeleton 55 for exerting localized pressure. While both expandable lasts may be provided with a core support ele ment or not, the substantially rigid L-shape of the forefoot spring element 56 of the expandable last 2 of Fig. 12 provides more inherent support to the spring skeleton 55, thus making it easier to provide the expansion assembly 40 without the core support element.

Fig. 13 shows an expandable last 2 in accordance with a twelfth exemplary em bodiment of the invention in a longitudinal cross-sectional view. Various compon ents of the expandable last 2 of Fig. 13 are identical / similar to the components of the expandable lasts discussed above. They are provided with corresponding reference numerals, and reference is made to their description above.

The expandable last 2 of Fig. 13 has an expandable shell 6, mounted to a lid 10. For the description of the expandable shell 6 and the lid 10, reference is made to the description of the expandable lasts discussed above. Within the expandable shell 6, a granulate chamber 61 is provided. A granulate port 62 is provided in the lid 10. The granulate port 62 forms a granulate channel into the granulate chamber 61. Via the granulate port 62, granulate 63 may be introduced into the expandable shell 6 and may be sucked out of the expandable shell 6. For illustrative purposes, a small amount of granulate 63 is shown within the granulate chamber 61 in Fig. 13. In the exemplary embodiment of Fig. 13, the granulate 63 is provided in the form of metal or glass balls, in particular metal or glass balls having a diameter of between 2 mm and 8 mm, further in particular having a diameter of between 3 mm and 6 mm. The metal may be steel. It is also possible that the granulate is provided in the form of sand.

The granulate 63 that is introduced into the granulate chamber 61 may be provided by an external granulate source 64. The external granulate source 64 has a granulate container 65 and a granulate heater 67. The granulate container 65 is coupled to the granulate port 62 with a granulate dosing valve 66, being in terposed between the granulate container 65 and the granulate port 62. Via the granulate heater 67 and the granulate dosing valve 66, the amount and temperat ure of the granulate 63 within the expandable shell 6 of the expandable last 2 may be controlled.

In operation, the granulate 63 may provide for a substantially uniform pressure onto the insert for pressing the same against the footwear. Also, with the granu late 63 being heated, the granulate 63 is an effective means for activating a heat- activated adhesive, which may be used for attaching the insert to the footwear. As described above, the expandable shell 6 may have, at least in one or more regions thereof, dimension-specific elastic properties. Also, as described above, a form-stable core support element or an expansion assembly may be arranged within the expandable shell 6. In this way, localized exertion of pressure may be combined with the more uniform exertion of pressure, as achieved via the granulate 63.

The expandable shell 6 of the expandable last 2 of Fig. 13 may be made from latex material, as described above with respect to various other embodiments of the expandable last. It is also possible that the expandable shell 6 of the expand able last 2 of Fig. 13 is made of synthetic material, in particular of a textile material. The expandable shell 6 may for example by a nylon sock. Test methods and definitions

The waterproofness of footwear may be determined by use of the Centrifuge test described in U.S Pat. No. 5,329,807, and incorporated by reference herein in its entirety. The centrifuge tests may be carried out for 30 minutes. The footwear article is considered to be waterproof if no leakage is seen after 30 minutes.

The breathability of footwear may be assessed in accordance with the determina tion of the Whole Boot Moisture Vapor Transmission Rate Test in accordance with the Department of Defense Army Combat Boot Temperate Weather Specifica tions. The specifications are as follows:

Whole boot breathability

The boot breathability test shall be designed to indicate the Moisture Vapor Transmission Rate (MVTR) through the test sample by means of a difference in concentration of moisture vapor between the interior and the exterior environment.

Apparatus a. The external test environment control system shall be capable of maintaining 23 (± 1) °C and 50% ± 2% relative humidity throughout the test duration. b. The weight scale shall be capable of determining the weight of test samples filled with water to an accuracy of (± 0.01) gram. c. The water holding bag shall be flexible so that it can be inserted into the test sample and conform to the interior contours; it must be thin enough so that folds do not create air gaps; it must have much higher MVTR than the footwear product to be tested; and it must be waterproof so that only moisture vapor contacts the interior of the footwear product rather than liquid water. d. The internal heater for the test sample shall be capable of controlling the temperature of the liquid water uniformly in the test sample to 35 (± 1) °C. e. The sealing method around the collar of the test sample shall be impervious to both liquid water and water vapor.

Procedure a. Place sample in test environment and condition for at least 12 hours. b. The heating device is inserted into the water holding bag and the complete as sembly is then placed into the test sample opening and filled with water to a height of 5cm measured from inside sole. c. Seal opening around the collar with plastic wrap around the top of the footwear and tape over using packaging tape. d. Heat water in test sample to 35 °C. e. Weigh test sample and record as Wi. f. Hold temperature in test sample after weighing for a minimum of 4 hours. g. After a minimum of 4 hours, reweigh test sample. Record weight as Wf and test duration as Td. h. Calculate MVTR of the test sample in grams/hour from the equation below: MVTR = (Wi - Wf)/Td.

This test is in accordance with ASTM D8041 (2016).

For example, for a low ankle shoe of European shoe size 42, the footwear may be considered breathable if above calculated value is above 1.5 grams/hour. For larger / smaller shoe sizes, said limit value may be extrapolated in accordance with the increased / decreased surface area of the shoe.

The waterproofness and the breathability of the bootie as a whole may also be determined by use of the Centrifuge test and the Whole Boot Moisture Vapor Transmission Rate Test, respectively, as laid out above.

While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without depart- ing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. Expandable last (2) for furnishing footwear (110) with an insert (100), comprising: an expansion assembly (40); an expandable shell (6), arranged around the expansion assembly (40); and a liquid chamber (8) within the expandable shell (6); wherein the expandable last (2) is insertable into the footwear (110) through a collar of the footwear (110) and wherein the expandable shell (6) is configured to expand for pressing the insert (100) towards an inside of the footwear (110); and wherein the expansion assembly (40) is configured to adapt its extension for exerting localized pressure onto the expandable shell (6) towards the inside of the footwear (110).

2. Expandable last (2) according to claim 1 , wherein the expansion assembly (40) comprises at least one of a hydraulically operated piston, a pneumatically operated piston (46), an electrically operated piston, and a spring-loaded piston (44) for exerting the localized pressure.

3. Expandable last (2) according to claim 2, wherein the expansion assembly (40) comprises a base plate (42), to which said at least one of a hydraulically operated piston, a pneumatically operated piston (46), an electrically operated piston, and a spring-loaded piston (44) is mounted.

4. Expandable last (2) according to any of claims 1 to 3, wherein the expansion assembly (40) comprises a spring-loaded piston (44) for exerting the localized pressure, wherein the spring-loaded piston (44) comprises at least one of a coil spring and a gas spring.

5. Expandable last (2) according to any of claims 1 to 4, wherein the expansion assembly (40) is configured to exert localized pressure onto at least one of a toe portion and a heel portion of the expandable shell (6).

6. Expandable last (2) according to claim 1 , wherein the expansion assembly (40) comprises a spring skeleton (55) having a forefoot spring portion (56), con- figured to exert localized pressure onto at least one of a toe portion and an instep portion of the expandable shell (6), and having a heel spring portion (57), con figured to exert localized pressure onto a heel portion of the expandable shell (6).

7. Expandable last (2) according to claim 6, wherein the forefoot spring portion (56) is configured to force its forefoot end portion in a forward and upward direction.

8. Expandable last (2) according to claim 6 or 7, wherein the forefoot spring portion (56) has a waved shape, with a first exposed portion (56a) exerting localized pressure onto the instep portion of the expandable shell (6) and with a second ex posed portion (56b) exerting localized pressure onto the toe portion of the expandable shell (6).

9. Expandable last (2) according to claim 6 or 7, wherein the forefoot spring por tion (56) comprises an instep spring element (58), extending along the instep portion of the expandable shell (6) and having its free end pointing rearwards.

10. Expandable last (2) according to any of claims 6 to 9, wherein the heel spring portion (57) is configured to force its heel end portion in a rearward and upward direction.

11. Expandable last (2) according to any of claims 6 to 10, wherein the expansion assembly (40) comprises a form-stable core support element (4), wherein the form-stable core support element (4) is in particular substantially L-shaped or sub stantially T-shaped.

12. Expandable last (2) according to any of claims 1 to 11 , further comprising a lid (10), to which the expandable shell (6) is mounted.

13. Expandable last (2) according to claim 12, wherein the expansion assembly (40) is fixed in position with respect to the lid (10), in particular mounted to the lid (10) via a mounting rod (54).

14. Expandable last (2) according to any of claims 1 to 13, wherein the expansion assembly (40) is attached to the expandable shell (6).

15. Expandable last (2) according to any of claims 1 to 14, further comprising a li quid port (16), providing liquid communication between the liquid chamber (8) and an external liquid source (120), wherein the expandable shell (6) is configured to expand for pressing the insert (100) towards an inside of the footwear (110), when receiving liquid in the liquid chamber (8) via the liquid port (16).

16. Expandable last (2) according to any of claims 1 to 14, further comprising a heater (60) arranged in the liquid chamber (8), wherein the heater (60) is configured to heat liquid in the liquid chamber (8) for expanding the expandable shell (6) and pressing the insert (100) towards an inside of the footwear (110) via an increase in volume of the liquid in the liquid chamber (8).

17. Expandable last (2) according to claim 16, wherein the heater (60) is an elec tric heater.

18. Expandable last (2) according to claim 16 or 17, wherein the expansion as sembly (40) and the heater (60) are fixed in position with respect to each other, wherein the expansion assembly (40) and the heater (60) are in particular formed as an integrated structural unit.

19. Expandable last (2) according to any of claims 16 to 18, further comprising a lid (10), to which the expandable shell (6) is mounted.

20. Expandable last (2) according to claim 19, wherein the expandable shell (6) and the lid (10) form a liquid -tight enclosure.

21. Expandable last (2) for furnishing footwear (110) with an insert (100), comprising: a form-stable core support element (4); an expandable shell (6), arranged around the core support element (4); a liquid chamber (8) within the expandable shell (6); and a liquid port (16), providing liquid communication between the liquid chamber (8) and an external liquid source (120); wherein the expandable last (2) is insertable into the footwear (110) through a collar of the footwear (110) and wherein, when receiving liquid in the liquid chamber (8) via the liquid port (16), the expandable shell (6) is configured to expand for pressing the insert (100) towards an inside of the footwear (110).

22. Expandable last (2) according to claim 21 , wherein the core support element (4) is substantially L-shaped or substantially T-shaped or substantially U-shaped or substantially foot-shaped.

23. Expandable last (2) according to claim 21 or 22, wherein the core support element (4) is rigid, in particular made from metal or rigid plastics material.

24. Expandable last (2) according to claim 21 or 22, wherein the core support element (4) is flexible, in particular made from resilient rubber material.

25. Expandable last (2) according to any of claims 21 to 24, wherein the liquid chamber (8) comprises substantially the entire volume between the core support element (4) and the expandable shell (6).

26. Expandable last (2) according to any of claims 21 to 25, wherein the core support element (4) comprises at least one liquid supply line (20), coupled to the liquid port (16) and providing liquid communication between the liquid port (16) and the liquid chamber (8).

27. Expandable last (2) according to claim 26, wherein the at least one liquid sup ply line (20) is arranged within the core support element (4) and has at least one opening (22) towards the liquid chamber (8).

28. Expandable last (2) according to any of claims 21 to 27, wherein the expandable shell (6) is elastic, in particular made from latex material.

29. Expandable last (2) according to any of claims 21 to 28, wherein the expandable shell (6) has, at least in one or more regions thereof, dimension-specific elastic properties.

30. Expandable last (2) according to any of claims 21 to 29, wherein the liquid chamber (8) is at least partly filled with an open-cell foam (24), in particular with an open-cell polyurethane foam, and/or with a spacer fabric.

31. Expandable last (2) according to any of claims 21 to 30, further comprising at least one expandable liquid bag (26), arranged outside or inside of the expand able shell (6).

32. Expandable last (2) according to claim 31, further comprising at least one an cillary liquid port (28), providing liquid communication between the at least one expandable liquid bag (26) and at least one external liquid source.

33. Expandable last (2) according to claim 32, further comprising at least one ancillary liquid supply line (30), coupling the at least one expandable liquid bag (26) to the at least one ancillary liquid port (28), wherein the at least one ancillary li quid supply line (30) in particular runs through the liquid chamber (8).

34. Expandable last (2) according to any of claims 31 to 33, wherein the at least one expandable liquid bag (26) comprises at least one of: an expandable liquid bag at an instep portion of the expandable shell (6); an expandable liquid bag at a toe portion of the expandable shell (6); an expandable liquid bag in a forefoot portion of the expandable shell (6); an expandable liquid bag in an upper midfoot portion of the expandable shell

(6).

35. Expandable last (2) according to any of claims 31 to 34, wherein the at least one expandable liquid bag (26) is at least partly filled with an open-cell foam, in particular with an open-cell polyurethane foam, and/or with a spacer fabric (34).

36. Expandable last (2) according to any of claims 21 to 35, further comprising a lid (10), to which the core support element (4) and the expandable shell (6) are mounted.

37. Expandable last (2) according to claim 36, wherein the liquid port (16) is arranged in the lid (10).

38. Expandable last (2) according to claim 36 or 37, wherein the lid (10) has an extension substantially corresponding to a transverse cross-section of the collar of the footwear (110).

39. Expandable last (2) according to any of claims 21 to 38, further comprising a heater, configured to heat the liquid in the liquid chamber (8) and/or to heat the expandable shell (6).

40. Expandable last (2) according to any of claims 21 to 39, configured for fur nishing the footwear with a waterproof, breathable bootie, the waterproof, breath- able bootie in particular being provided, on its outside, with pressure sensitive adhesive and/or heat-activated adhesive for attachment to the inside of the foot wear.

41. Expandable last (2) for furnishing footwear (110) with an insert (100), comprising: an expandable shell (6); a liquid chamber (8) within the expandable shell (6); and a liquid port (16), providing liquid communication between the liquid chamber (8) and an external liquid source (120); wherein the expandable last (2) is insertable into the footwear (110) through a collar of the footwear (110) and wherein, when receiving liquid in the liquid cham ber (8) via the liquid port (16), the expandable shell (6) is configured to expand for pressing the insert (100) towards an inside of the footwear (110); and wherein the expandable shell (6) has, at least in one or more regions thereof, dimension-specific elastic properties.

42. Expandable last (2) according to claim 41 , wherein the expandable shell (6) is configured to expand more easily in a longitudinal dimension (72) than in a circumferential dimension (74) in at least one of a midfoot portion (70) and a forefoot portion.

43. Expandable last (2) according to claim 41 or 42, wherein the expandable last (2) is free of a form-stable core support element and/or free of an expansion assembly, arranged within the expandable shell.

44. Expandable last (2) for furnishing footwear (110) with an insert (100), comprising: a rigid last portion (80, 82); an expandable shell (6), arranged adjacent to the rigid last portion (80, 82); a liquid chamber (8) within the expandable shell (6); and a liquid port (16), providing liquid communication between the liquid chamber (8) and an external liquid source (120); wherein the expandable last (2) is insertable into the footwear (110) through a collar of the footwear (110) and wherein, when receiving liquid in the liquid cham ber (8) via the liquid port (16), the expandable shell (6) is configured to expand for pressing the insert (100) towards an inside of the footwear (110).

45. Expandable last (2) according to claim 44, wherein the rigid last portion (80, 82) is made from metal, such as aluminum.

46. Expandable last (2) according to claim 44 or 45, wherein the rigid last portion (80, 82) is heatable.

47. Expandable last (2) according to any of claims 44 to 46, comprising a rigid forefoot and instep last portion (80) and a rigid heel last portion (82), wherein the expandable shell (6) is arranged between the rigid forefoot and instep last portion (80) and the rigid heel last portion (82).

48. Expandable last (2) according to claim 47, wherein the rigid forefoot and in step last portion (80) and the rigid heel last portion (82) are movable with respect to each other and wherein the expandable last comprises an actuator (84) for controlling a spacing between the rigid forefoot and instep last portion (80) and the rigid heel last portion (82), with the actuator (84) in particular being a pneu matic or hydraulic or electric actuator.

49. Expandable last (2) according to any of claims 44 to 48, further comprising at least one expandable liquid bag (26), arranged on an outside of the rigid last portion (80, 82).

50. Expandable last (2) according to claim 49, wherein the at least one expandable liquid bag (26) comprises at least one expandable liquid bag in a toe region and/or in a heel region of the expandable last (2), in particular an expandable li quid bag in a toe region of the rigid forefoot and instep last portion (80).

51. Expandable last (2) for furnishing footwear (110) with an insert (100), com prising: an expandable shell (6); a granulate chamber (61) within the expandable shell (6); and a granulate port (62), providing a granulate channel between the granulate chamber (61) and an external granulate source (64), in particular between the granulate chamber (61) and an external heated granulate source (64); wherein the expandable last (2) is insertable into the footwear (110) through a collar of the footwear (110) and wherein, when receiving granulate (63) in the granulate chamber (61) via the granulate port (62), the expandable shell (6) is configured to expand for pressing the insert (100) towards an inside of the foot wear (110).

52. Method for furnishing footwear (110) with an insert (100) using an expandable last (2) according to any of the preceding claims.

53. Method according to claim 52, wherein the insert (100) is a waterproof, breathable bootie.

54. Method for furnishing footwear (110) with an insert (100), the method comprising: inserting an expandable last (2) into the footwear (110) through a collar of the footwear (110), the expandable last (2) having an expandable shell (6) and a liquid chamber (8) within the expandable shell; and pressing the insert (100) towards an inside of the footwear (110) by expanding the expandable shell (6) via liquid in the liquid chamber (8).

55. Method according to claim 54, wherein said expanding of the expandable shell (6) via liquid in the liquid chamber (8) comprises introducing liquid into the li- quid chamber (8).

56. Method according to claim 54 or 55, wherein said expanding of the expand able shell (6) via liquid in the liquid chamber (8) comprises heating the liquid in the liquid chamber (8).

57. Method according to any of claims 54 to 56, wherein the insert (100) is a waterproof, breathable bootie.