US20140013630A1

US20140013630A1 - Shoe for practicing sports involving gliding over the snow or for walking

Info

Publication number: US20140013630A1
Application number: US14/000,510
Authority: US
Inventors: Pierre Gignoux; Franck Constant; Thomas Saillet
Original assignee: Salomon SAS
Current assignee: Salomon SAS
Priority date: 2011-02-21
Filing date: 2012-02-20
Publication date: 2014-01-16
Also published as: RU2013142929A; RU2607765C2; EP2677891A2; WO2012114002A2; WO2012114002A3; FR2971675A1; FR2971675B1

Abstract

Boot (1) intended for the practice of sports involving gliding on snow or walking, characterized in that it includes an outer shell (2, 2′, 20, 26, 26′, 34, 42) made of a rigid material, the shell (2, 2′, 20, 26, 26′, 34, 42) including a rear cradle (22, 28, 28′, 39, 44) provided to hold the heel of the user, the rear cradle (22, 28, 28′, 39, 44) being extended forward by a blade-shaped portion (6) defining a bending zone, the rear cradle (22, 28, 28′, 39, 44) comprising a peripheral wall (5, 31) and a bottom, the bottom of the cradle and the blade-shaped portion partially defining the sole assembly of the boot, and characterized in that it includes an inner liner (20).

Description

The invention relates to a shoe adapted to the practice of sports involving gliding on snow, or walking. The invention relates more particularly to a boot suitable for the practice of Nordic skiing, such as cross-country skiing or ski touring, mountaineering skiing, ski mountaineering or telemark, that is to say, a practice for which a user alternately lifts the heel. The invention also relates to a boot adapted to the practice of mountain walking or mountaineering. The invention also relates to a shell for a sports shoe.
The practice of these activities, or of an activity such as cross-country skiing requires the use of boots that are relatively torsionally rigid, between the front and rear of the boot, in order to accurately transmit the foot actions to the ski, while retaining the bending flexibility necessary for the foot rolling movement in the area of the metatarsal joint.
With respect to cross country skiing itself, the aforementioned relative rigidity was lacking in the early cross country ski boots when the so-called “skating step” technique was first introduced. However, a technical solution has been found, involving the use of reinforcements generally made of composite materials, which are superimposed and connected to the existing structure made of synthetic and/or thermoplastic materials. Indeed, the cross-country ski boot conventionally have an assembled construction, in which the boot includes a flexible upper mounted on a lasting board, the assembly being glued onto an outer sole, and the reinforcing elements generally being attached to the outside of the upper, to complement the conventionally used reinforcements and stiffeners.
The boots thus produced are more rigid, thereby allowing for better control of the ski and balance; but they have also become heavier, as the additional reinforcements add to the weight of the boot, even if they are made of the lightest possible materials.
More generally speaking, the boots according to the prior art have an upper and a sole assembly with quite complex structures, for a high weight. The complexity is due to the multitude of components required to manufacture the upper, on the one hand, and the sole assembly, on the other hand. The upper includes at least a first envelope providing the general appearance of the boot, a stiffener for supporting the heel, localized reinforcements added to the first envelope to obtain localized increases in mechanical strength; as well as a second envelope or liner, housed in the first envelope, to perform one or more functions such as providing comfort, thermal insulation, or the like. The sole assembly includes at least a first lasting board, adapted to hold the constituent elements of the upper together. The sole assembly further includes an outsole, adapted to contact the ground, as well as an insole, housed in the envelopes. It should be noted in passing that the outsole often includes two or more layers, including a wear layer and a damping layer.
Still with respect to boots according to the prior art, the complexity of the structure renders the manufacturing complex. Indeed, it is necessary to group the constituent elements of the upper together, by applying them onto a blank, and then by holding them, generally using an adhesive, on the lasting board. The subassembly thus made then receives the outsole and the insole. Thus, the manufacture is quite complex and, ultimately, given the number of components, the resulting boot is quite heavy.
Furthermore, a more or less substantial flexural rigidity is sometimes necessary in the cross-country, alpine, or mountaineering ski boot. There is currently no response to this constraint, and the only solution is to have a plurality of boots, depending upon the practice. In cross-country skiing, for example, it is necessary to have a pair of flexurally flexible boots to practice the so-called classic technique, and a pair of flexurally rigid boots to practice the skating step technique. This can be particularly difficult in competitions combining two events, such as a classic event immediately followed by a skating step event without interrupting the timer. The boots used for these types of events are hybrid boots in which rigidity is intermediate between the two types of boots. Therefore, this compromise is not ideal for neither of these two skiing techniques.
Broadly speaking, the invention provides a boot, adapted to the practice of a sport involving gliding on snow or walking, as mentioned above, which concurrently has good torsional rigidity, good flexural flexibility, and reduced weight. Thus, the invention seeks to reduce user fatigue, or to help improve user performance.
One of the objects of the present invention is therefore to overcome the drawbacks of the prior art by providing a Nordic ski boot having with good torsional rigidity, good flexural flexibility, and reduced weight, while meeting comfort requirements.
An object of the invention is also to provide an adaptable boot, whose rigidity is adjustable depending upon the practice.
To this end, the invention provides a boot adapted to the practice of sports involving gliding on snow or walking. The boot according to the invention is characterized in that it includes an outer shell made of a rigid material, the shell including a rear cradle adapted to hold the heel of the user, the rear cradle being extended forward by a blade-shaped portion defining a bending zone, the rear cradle comprising a peripheral wall and a bottom, the bottom of the cradle and the blade-shaped portion partially defining the sole assembly of the boot, and characterized in that it includes an inner liner.
The shell includes the rear cradle and the blade-shaped portion and, consequently, the boot has good torsional rigidity and good flexural flexibility. The liner arranged in the shell provides the boot with a minimum of use comfort. It can be said that the invention separates the elements of the boot depending on their intended function, that is to say, either a function of transmission of sensory information or of transmission of steering impulses, by the torsional rigidity or the flexural flexibility of the shell, or a function of providing comfort, retention and/or envelopment for the foot, by arranging the liner in the shell. The separation of the elements of the boot simplifies the structure thereof, compared to a boot with integrated upper according to the prior art. The separation of the elements also makes it possible to optimize the structure or function thereof. In the invention, by placing a single material where necessary, and thus by avoiding duplicative layer overlays, the boot obtained includes a reduced number of parts. The separation of functions makes it possible to optimize each element, in particular the reinforcing element, and thus to minimize the weight. This means that the structure created by the invention lightens the boot. A resulting technical effect is a reduction in its mechanical inertia, compared to a boot according to the prior art. To summarize, it can be said that an advantage of the boot of the invention is to reduce user fatigue or, as a corollary, to increase user performance, while retaining the qualities of the boots of the prior art, in particular the torsional rigidity and flexural flexibility.
Paradoxically, the boot according to the invention has successfully reconciled two conflicting characteristics, including the steering or support accuracy, on the one hand, and comfort, on the other hand, while reducing the weight of the boot. Indeed, the shell made of a rigid material, despite its s torsional and flexural characteristics, also brings a certain comfort. For example, for a cross-country ski boot, the shell located outside stiffens the boot, but this shell is sufficiently thin to adapt to the foot and to wrap the latter with precision. This paradoxically contributes to making the boot comfortable, despite the use of rigid materials.
According to one or more other characteristics of the boot, taken individually or in combination,

- the thickness of the peripheral wall of the rear cradle is less than 1.5 millimeters,
- the thickness of the peripheral wall of the front cradle is less than 1.5 millimeters,
- the shell includes a front cradle the blade-shaped portion connecting the rear cradle to the front cradle, the blade-shaped portion extending in the area of the metatarsus of the user, a recess being located between the rear cradle and the front cradle in the area of the blade-shaped portion,
- the rear cradle and the blade-shaped portion are unitary elements,
- the rear cradle and the blade-shaped portion are separate elements,
- the thickness of the blade-shaped portion in the bending zone is less than 4.0 millimeters,
- the thickness of the peripheral wall tapers off between the bottom and the upper opening,
- the minimum width of a recess of the bending zone is at least greater than 5.0 millimeters,
- the minimum width of a recess of the bending zone is between 20 and 30 millimeters, and is preferably on the order of 25 millimeters,
- the shell is entirely made of composite materials, and the thickness of the peripheral wall is between 0.5 and 1.2 millimeters,
- the shell is entirely made of carbon fibers, and the thickness of the peripheral wall is between 0.5 and 0.8 millimeters,
- the peripheral wall at least is made of glass fibers, and the thickness of said peripheral wall is between 0.8 and 1.2 millimeters,
- the blade-shaped portion is made of composite materials and includes unidirectional fibers of the composite material in the bending zone,
- the bending zone defines a front cradle and a rear cradle, the materials of the front and rear cradles being different from one another, the blade-shaped portion being made of carbon fibers,
- lightening holes are provided in the rear cradle,
- at least one cradle is made of a plastic material, and the thickness of the cradle is less than or equal to 1.5 millimeters,
- the bending zone of the blade-shaped portion is thicker than the remainder of the blade-shaped portion,
- the bending zone comprises fibers which form an angle with the longitudinal axis of the boot,
- the bending zone defines a front cradle and a rear cradle, the shell comprising the front cradle and the rear cradle, the shell comprising a means for fixing the front and rear cradles in the area of an overlapping of the front and rear bottoms of the cradles,
- the bottom of the rear cradle extends beneath the bottom of the front cradle, the fixing means being arranged beneath the front cradle,
- the front bottom extends beneath the rear bottom, the fixing means being arranged beneath the rear cradle,
- the fixing means is removable,
- the shell is a unitary element,
- the shell comprises a stiffening blade extending at least beneath the bending zone, said stiffening blade being capable of assuming an active position in which said stiffening blade thickens the sole assembly in the bending zone, and an inactive position in which the end of the stiffening blade is free,
- the free end of the stiffening blade extends rearward of the bending zone,
- the free end of the stiffening blade is adapted to be retained in the active position by a removable retaining means,
- the shell comprises lateral protective upright panels in the area of the malleoli,
- the bending zone defines a front cradle and a rear cradle, and the front cradle has a central upper recess,
- the shell comprises through holes adapted to receive fixing screws, and it comprises inner shoulders arranged around the through holes, adapted to house the heads of said fixing screws.

With respect to the stiffening blade, it should be noted that the boot according to the invention overcomes the disadvantage related to the lack of adjustment of the flexural rigidity, by providing rigidity that is adjustable depending upon the type of practice. Thus, the same boot can be flexurally flexible in one case and flexurally rigid in another case, simply by activating a linkage between the shell and an auxiliary blade.
Therefore, the shell comprises a blade overlying the sole assembly and affixed thereto forward of the bending zone, but independent thereof beneath and rearward of the bending zone. The primary function of this blade is to stiffen the shell in reverse bending, that is to say, when the foot moves backward and the front of the boot is retained on the ski, for example. This is especially useful for a mountain ski boot, which tends to bend inversely during support on the upper portion of the boot. The boot devoid of this blade might then simply break during rear support.
The second function of this blade is to stiffen the shell flexurally when the blade is coupled to the shell. The same shell thus allows obtaining a boot that is flexible in one case and rigid in another case.
The invention also relates to a shell provided to be integral with a boot as mentioned above.
According to a first embodiment, the bending zone defines a front cradle and a rear cradle in the shell, and the boot comprises two straight stays connecting the walls of the rear cradle to the walls of the front cradle, respectively.
According to another example of embodiment, the bending zone defines a front cradle and rear cradle in the shell, and the boot comprises a Y-shaped stay connecting the walls of the rear cradle to the front cradle.
The bending zone enables the ski boot to be flexurally flexible in the area of the metatarsal joint to allow for foot rolling movement during skiing. The thickness of the peripheral wall of the cradle, with a maximum less than 1.5 millimeters, makes it possible to obtain a ski boot having both required qualities of rigidity and low weight.
The cradles are very thin on the lateral and medial portions, which provide a certain flexibility useful for comfort and necessary to tighten the foot without weighing down the shell. In addition, the cradle shapes of the shell enable it to have great rigidity at the front and rear.
Due to the composite materials, excellent rigidity and low weight can be obtained with a very small thickness in the lateral and medial portions, ranging between 0.5 and 1.2 millimeters. It is thus possible to obtain ski boots weighing about 300 g per foot, instead of 600 g to 700 g for a boot of the prior art.
Furthermore, with the blade-shaped portion having a thickness with a maximum of less than 4.0 millimeters in the bending zone being, bending is comfortable in the area of the metatarsal joint.
Thus, with a thickness of the peripheral wall of the cradle being less than 1.5 millimeters and a bending zone formed by recesses between the cradles, the shell has good torsional rigidity while having good flexural flexibility and reduced weight.
The geometry and selection of materials for the shell make it possible to obtain a boot having good torsional rigidity and good flexural flexibility, in addition to being comfortable.
Furthermore, the use of a stiffening blade enables the latter, in reverse bending, to stiffen the sole assembly in the active position, and to prevent this reverse bending of the shell. This is particularly useful for a mountain ski boot, which tends to bend inversely during support on the collar of the boot. A shell devoid of the blade might simply break during rear support.
Thus, the same boot can be used for various practices of Nordic skiing. The stiffening blade is deactivated to obtain a flexurally flexible boot more adapted to the so-called classic practice, and the stiffening blade is activated to obtain a more flexurally rigid boot that is better suited to practice of the skating step.
Depending on the position of the end of the stiffening blade, the same boot can thus have a different flexural rigidity. This adjustability is particularly advantageous in competition for example combining two events, such as a classic event immediately followed by a skating step event without interrupting the timer. This avoids the use of hybrid boots in which rigidity is intermediate between a flexible boot and a rigid boot, and which would be a rather unsatisfactory compromise in both practices.

Other advantages and characteristics will become apparent from reading the description of the invention, and from the annexed drawing figures, in which:

FIG. 1 is a perspective view of the lateral side profile of a Nordic ski boot according to a first embodiment, in a case in which the inner liner is not arranged in the shell,

FIG. 2 is a view of the medial side profile of the boot of FIG. 1,

FIG. 3 is a bottom view of the boot of FIG. 1,

FIG. 4 is a perspective view of the lateral side profile of the shell of the ski boot, according to one of FIGS. 1-3,

FIG. 5 shows the shell of FIG. 4, in which an inner liner is inserted,

FIG. 6 is a perspective view of the right medial profile of the inner liner of FIG. 5,

FIG. 7 is a perspective bottom view of a shell on which zones provided with protections are shown schematically,

FIG. 8 is a schematic side view of an alternative embodiment of the shell,

FIG. 8 bis is a top view of the shell of FIG. 8,

FIG. 9 is a top view of the shell of FIG. 8,

FIG. 10 is a cross-sectional view along the line AA of the blade-shaped portion in the bending zone of the shell of FIG. 8,

FIG. 11 is a perspective view of the medial profile of a Nordic ski boot shell according to a second embodiment in the assembled state,

FIG. 12 is a perspective top view of the shell of FIG. 11, in the disassembled state,

FIG. 13 is a bottom view of the shell of FIG. 11, in the disassembled state,

FIG. 14 a is a schematic, longitudinal cross-sectional view of a shell for a Nordic ski boot according to a third embodiment,

FIG. 14 b is a cross-sectional view of a shell for a Nordic ski boot according to a fourth embodiment, which is a variation of the third embodiment,

FIG. 15 a is a schematic cross-sectional view along a longitudinal median plane of the shell according to a fifth embodiment,

FIG. 15 b is a bottom view of the shell of FIG. 15 a, with the stiffening blade in the active position,

FIG. 15 c is a cross-sectional view along a longitudinal median plane of a boot provided with the shell of FIG. 15 a fixed to a ski, with the foot in reverse bending and the stiffening blade in the active position, the liner not being shown,

FIG. 15 d shows the boot of FIG. 15 c fixed to the ski, with the foot bent and the stiffening blade in the inactive position,

FIG. 15 e shows the boot of FIG. 15 c fixed to the ski, with the foot bent and the stiffening blade in the active position,

FIG. 16 a is a perspective view of a shell according to a sixth embodiment,

FIG. 16 b shows a variation of a shell according to a seventh embodiment, and

FIG. 17 is similar to FIG. 8, for an eighth embodiment.

In these drawing figures, identical elements are designated by the same reference numerals.
The upper, lower, front and rear, lateral and medial positions are used with reference to the foot of a user.
FIGS. 1 to 3 show a ski boot 1 intended for the practice of Nordic skiing, during which the skier alternatively lifts the heel, such as when practicing telemark, ski touring, or cross-country skiing. The inner liner is not shown. In the description, the various types of skiing enabling the practice of the Nordic skiing disciplines are generically designated by cross-country skiing, or even just skiing.
The boot 1 comprises a shell 2 (FIG. 4), a sealing outer layer 3 partially enveloping the shell 2, and a collar 4 articulated to the shell 2 (FIGS. 1 and 2).
More clearly visible in FIG. 4, the shell 2 comprises a peripheral wall 5 above a sole assembly portion 6 and an upper opening 7 arranged in the upper portion of the peripheral wall 5 for insertion of the skier's foot.
The shell 2 is an envelope having a shape adapted to surround a foot. The shell 2 is relatively rigid but has a bending zone Z located in the area of the metatarsal joint. The bending zone Z is formed by recesses in the peripheral wall 5 of the shell 2. The recesses are two lateral and medial zones extending on both sides of the upper opening 7, from the upper opening 7 to the sole portion 6. The bending zone Z enables the ski boot 1 to be flexurally flexible in the area of the metatarsal joint, in order to enable the rolling movement of the foot during skiing.
The bending zone Z thus demarcates a front cradle or end piece toward the tip of the shell 2, and a rear cradle toward the heel of the shell 2.
The upper opening 7 of the shell 2 extends at least from the zone of the ankle to the bending zone Z, which gives a certain flexibility to the peripheral wall 5 in the area of the rear cradle, and thereby enables the foot to be tightened and supported.
The front cradle makes it possible to protect the toes of the skier and participate in supporting the foot. The front cradle can have a central upper recess 8, in the extension of the upper opening 7, as shown in FIG. 4. It can be seen below that the front cradle can also be removed and replaced by a simple protective toe cap without special stiffening function.
The lateral and medial recesses of the bending zones Z can have opposite parallel edges, the recesses being for example slightly angled towards the tip of the shell 2, as shown in FIGS. 4 and 5. In another example shown in FIG. 8, the recesses of the bending zone Z are flared upward. It is preferred to have recesses with opposite parallel or upwardly flared edges so that in bending, the front cradle does not contact the rear cradle.
The width If of the recesses of the bending zone Z at the narrowest point (FIGS. 4 and 8) is at least greater than 5.0 millimeters to allow for the bending. The width lf ranges for example between 20 and 30 millimeters, and is preferably on the order of 25 millimeters.
It is further provided that the thickness ep of the lateral and medial portions of the peripheral wall 5 has a maximum of less than 1.5 millimeters, which makes it possible to obtain a ski boot 1 having both required qualities of rigidity and low weight.
The cradles are very thin on the lateral and medial portions, which provide a certain flexibility useful for comfort and necessary to tighten the foot without weighing down the shell. In addition, the cradle-shapes of the shell provide the latter with great rigidity at the front and rear.
The shell 2 is for example made entirely of composite materials, such as carbon fibers, glass or aramid fibers. The composite materials make it possible to obtain excellent rigidity and low weight, with a very small thickness in the medial and lateral portions between 0.5 and 1.2 millimeters. It is thus possible to obtain ski boots weighing about 300 g per foot, instead of 600 g to 700 g for a boot of the prior art.
With a shell made of composite material, the fibers of the blade-shaped portion 6 can also be provided to be unidirectional in the bending zone Z.
As shown in FIG. 8 bis, at least a percentage of the constituent fibers of the blade-shaped portion are oriented along the longitudinal direction L of the boot. These fibers are for example located in the thickness of the blade-shaped portion, that is to say, apart from the surfaces which demarcate it. It can also be said that the unidirectional fibers are located in a central region of the blade-shaped portion, thickness-wise.
Alternatively, and as shown in FIG. 9, the blade-shaped portion 6 is made of composite materials, and the fibers of composite materials are crisscrossed in the bending zone. First fibers form an angle ranging for example between +40° and +70° with the longitudinal axis L of the blade-shaped portion 6; and second fibers form an angle ranging for example between −40° and −70° with the longitudinal axis L of the blade-shaped portion 6. For example, the first fibers form an angle of about 60° with the longitudinal axis L, and the second fibers form an angle of about −60°. The crisscrossed fibers make it possible to provide continuity of the torsional rigidity of the shell 2′ in the bending zone Z substantially less rigid in torsion of the recesses.
The shell 2, 2′ is for example entirely made of carbon fibers. In this case, good rigidity and low weight can be obtained with a thickness of the lateral and medial portions ranging between 0.5 and 0.8 millimeters.
According to another example, at least the peripheral wall 5 is made of glass fibers. In this case, good rigidity and low weight can be obtained with a thickness of the lateral and medial portions of the upper portion 5 ranging between 0.8 and 1.2 millimeters.
To further reduce the weight without sacrificing the qualities of rigidity, one can provide to arrange lightening holes in the peripheral wall 5 of the shell 2, forming a grid-like shell (not shown), for example.
According to another example, at least the peripheral wall 5 is made of an injected plastic material. In this case, good rigidity and low weight can be obtained with a thickness of the lateral and medial portions of the lower peripheral wall being less than or equal to 1.5 millimeters. The shell 2, 2′ is then provided to comprise lightening holes to ensure low weight while having good rigidity.
The materials of the front and rear cradles can also be envisioned to be different from one another, selected for example from various composite materials (carbon fiber, glass or aramid fiber) and/or by associating a composite material with a plastic material. However, it is preferred that the blade-shaped portion 6 be made of carbon fibers.
Furthermore, the thickness d of the blade-shaped portion 6 in the bending zone Z is provided to have a maximum of less than 4.0 millimeters, in order to allow for comfortable bending in the area of the metatarsal joint. FIG. 10 shows a cross-section of the blade-shaped portion 6 in the bending zone Z. The four millimeters thickness d represents the maximum thickness between the highest point and lowest point of the thickness of the blade-shaped portion 6 in the bending zone Z.
In particular, the thickness ep of the lateral and medial portions of the wall 5 can also be provided to taper off between the blade-shaped portion 6 and the upper opening 7. For example, for a shell 2 made entirely of carbon fibers, the thickness in the area of the blade-shaped portion 6 can vary and can range between 1.2 millimeters in the vicinity of the blade-shaped portion 6 and change to about 0.5 millimeters in the area of the upper opening 7. The thinning of the thickness ep of the peripheral wall 5 locally increases its flexibility, particularly in the area of the lateral and medial portions, thereby enabling a progressive and enveloping tightening of the rear cradle around the foot.
In this first embodiment, whether it is made of one or more different materials, the shell 2, 2′ is a unitary element, that is to say, it comprises a single piece. The shell 2, 2′ has a uniform and smooth surface, and the blade-shaped portion 6 and the peripheral wall 5 are connected continuously. Thus, the shell 2, 2′ is comfortable for the user's foot.
Thus, with a thickness of the lateral and medial portions of the peripheral wall 5 being less than 1.5 millimeters and a bending zone Z formed by recesses in the wall 5 of the shell 2, 2′ extending from the upper opening 7 of the wall 5 to the blade-shaped portion 6, the shell 2, 2′ has good torsional rigidity while having good flexural flexibility and reduced weight.
The boot 1 further comprises a front fixing element 9 associated with the blade-shaped portion 6 of the shell 2, upstream of the bending zone Z (FIG. 3). The front fixing element 9 is provided with a transverse pivot 10 rotatably assembled to the front binding to the ski. The front fixing element 9 is for example screwed into the front cradle of the shell 2. For this, the shell 2 can be provided to have through holes and inner shoulders arranged around the through holes. The inner shoulders are provided within the shell 2. The through holes are adapted to receive fixing screws 11. The shoulders are adapted to receive and completely house the heads of the fixing screw heads (or the nuts). This ensures that the fixing screws 11 are fully integrated within the shell 2 and cannot injure the foot of the user.
To improve user comfort and to ensure good transverse support of the ankle, the shell 2, 2′ can also comprise lateral and medial protective upright panels 12 on both sides of the malleoli, to better protect the malleoli of the user. One can further provide to articulate the collar 4 of the boot 1 on these upright panels 12.
Furthermore, the rear bottom portion of the blade-shaped portion 6 (or heel) can define two guiding grooves 48 for the transverse retention of the boot 1 affixed to the ski binding when the heel of the boot is supported on the ski.
The sealing outer layer 3 is made of an impervious, hydrophobic material to withstand snow, rain and ice, and of an elastic material to facilitate the insertion of the foot into the upper opening. It is for example made of a neoprene-based stretch fabric, a polyurethane layer, or any equivalent material. The sealing outer layer 3 is for example fixed to the edges of the blade-shaped portion 6, on the one hand, and to the rear cradle, on the other hand. The sealing outer layer 3 covers the lateral and medial recesses of the bending zone Z and a portion of the upper opening 7. It thus makes it possible to protect the user's foot.
The boot 1 also comprises an inner liner 20, for example made of a polar fabric, received in the shell 2, 2′. The inner liner 20 is used to provide softness and warmth to the user, and prevents the foot from rubbing the edges of the shell 2. It also makes it possible to cover the foot of the user in the bending zone Z. An example of inner liner 20 is shown in FIGS. 5 and 6.
In the illustrative example of FIGS. 1 and 2, the boot 1 also comprises two tightening straps 13 a, 13 b and a band 14. The band 14 tightens the boot on the foot of the user, obliquely between the bending zone Z and the rear cradle. The first tightening strap 13 a is adapted to connect the lateral and medial portions of the rear cradle in the area of the instep. It makes it possible to adjust the tightening of the rear cradle. The first tightening strap 13 a and the band 14 also make it possible to keep the sealing outer layer 3 and the shell 2 together on the user's foot. The second tightening strap 13 b is adapted to adjust the tightening of the collar 4 around the ankle of the user. Of course, alternatively or complementarily, the boot can include other tightening means, such as a lace device or any equivalent.
In order not to unnecessarily weigh down the shell 2, only certain preferred contact zones are provided with protective elements to protect the shell 2 and to make it possible to walk safely. The zones provided with these elements include, for example, the heel zone 15 defining the guiding grooves 48 and the front zone 19 of the shell 2, which are the contact zones at the beginning and at the end of the step, the medial 16 and lateral 17 zones of the bending zone Z, as well as the lower central portion 18 of the bending zone Z, which are preferred support zones of contact with the ski for the standing position or during foot rolling movement (FIG. 7). The protective elements 16 and 17 are provided to protect the bending zone Z, particularly in the area of the recesses, against impacts or friction in a track in the snow.
Thus, the geometry and selection of materials for the shell 2, 2′ make it possible to obtain a boot 1 having good torsional rigidity and good flexural flexibility, in addition to being comfortable.
According to a second embodiment shown in FIGS. 11, 12, 13, 14 a and 14 b, the shell is made of a plurality of distinct elements assembled together.
In the first example shown in FIGS. 11, 12 and 13, the shell 20 is made of three elements: the front cradle 21, the rear cradle 22, and the blade-shaped portion 23. The front cradle 21 and rear cradle 22 are made of glass fibers, for example, and the blade-shaped portion 23 is made of carbon fibers. The front and rear cradles 21, 22 have rounded shapes, especially in the bending zone Z. These three elements 21, 22, 23 are affixed to one another, for example by gluing, welding, or mechanical assembly between the lower edges of the cradles and the edge of the blade-shaped portion 23.
The front fixing element 24 of the boot is visible in FIG. 13. One can also see in FIG. 12 that the heads of the fixing screws 11 are received in the inner shoulders provided inside the shell 20 and do not project therefrom.
Moreover, in this example, the front fixing element 24 comprises an additional transverse bar 25 set back relative to the transverse pivot 10. The additional transverse bar can be used as an option, by being connected to an elastic return means connected to the ski. This option is more particularly suitable to practice the alternate step or classic technique, which involves moving in two parallel tracks.
According to one example shown in FIGS. 14 a and 14 b, the shell 26, 26′ is made of two distinct elements assembled together, i.e., the front cradle 27, 27′ and the rear cradle 28, 28′.
Referring to FIG. 14 a, the front cradle 27 comprises a peripheral wall 29 and a blade-shaped portion 30, and the rear cradle 28 includes a peripheral wall 31 and a blade-shaped portion 32. The shell 26 further comprises a means 33 for fixing the front 27 and rear 28 cradles in the area of overlap of the front and rear blade-shaped portions 30, 32.
The fixing means is removable, for example. For example, the fixing means 33 is provided to comprise at least one fixing screw. Thus, it is possible to adjust the ski boot to the skier foot size and the width of the recesses of the bending zone Z by more or less advancing the front cradle 27 relative to the rear cradle 28.
In the example of FIG. 14 a, the front blade-shaped portion 30 extends beneath the rear blade-shaped portion 32. The fixing means 33 comprises two fixing screws which are inserted beneath the rear peripheral wall 31, into the front blade-shaped portion 30 and extend into the rear blade-shaped portion 32, thus connecting the two cradles 27, 28 to one another.
In the example of FIG. 14 b, the rear blade-shaped portion 32′ extends beneath the front blade-shaped portion 30′. The fixing means 33′ comprises a single fixing screw which is inserted beneath the front peripheral wall 29′, into the rear blade-shaped portion 32′ and extends into the front blade-shaped portion 30′, thus connecting the two cradles 27′, 28′ to one another.
Alternatively, the front and rear cradles 27, 28, 27′, 28′ are permanently affixed to one another, for example by gluing, welding, or mechanical assembly.
It is further possible to insert a flexible layer between the front and rear blade-shaped portions or bottoms 30, 32, 30′, 32′.
Thus, in either one of these two embodiments, the blade-shaped portion 30, 32, 30′, 32′ is not doubled in the bending zone Z and remains less than 4.0 millimeters to enable bending of the boot.
FIGS. 15 a, 15 b, 15 c, 15 d and 15 e show a fifth embodiment, in which the shell 34 comprises a stiffening blade 35.
As can be seen in FIGS. 15 a and 15 b, the stiffening blade 35 extends at least beneath the bending zone Z. It is adapted to assume an active position in which it thickens the blade-shaped portion 36 in the bending zone Z by being superimposed on the blade-shaped portion 36 (FIG. 15 e), and an inactive position in which the end 37 of the stiffening blade 35 is free (FIG. 15 d).
The free end 36 of the stiffening blade 35 extends for example toward the rear of the bending zone Z, the front end being affixed to the blade-shaped portion 36 of the front cradle 38. The stiffening blade 35 for example is broader in shape toward the front than toward the rear. The rear side tapers off towards the free end 37.
Thus, the stiffening blade 35 is active in reverse bending, that is to say that when the user leans backwards (arrow F1), and the front of the boot is maintained on the ski 50, for example (FIG. 15 c). The Stiffening blade 35 stiffens the blade-shaped portion 36 in the active position and prevents this reverse bending of the shell 34. This is particularly useful for a mountain ski boot, which tends to fold backwards (along the direction F1) during support on the collar 4 of the boot. A shell devoid of the blade might simply break during rear support.
The free end 37 can further be retained in the active position, that is to say, affixed to the blade-shaped portion 36 of the rear cradle 39 by a removable retaining means.
The removable retaining means comprises for example a pivot 40 that is manually actuatable by a locking lever 41 affixed to the pivot 40 (FIG. 15 b). The pivot 40 can thus pivot (arrow F2 in FIG. 15 b) between the active position, in which it retains the end 37 of the stiffening blade 35 to the blade-shaped portion 36 (FIG. 15 b), and an inactive position in which the pivot 40 is pivoted apart from said end 37 (FIG. 15 a).
Because the front end of the stiffening blade 35 is affixed to the blade-shaped portion 36 of the front cradle 38, the free end 37 of the stiffening blade 35 is biased in the inactive position during foot rolling movement. Thus, when the shell 34 is bent and the stiffening blade 35 is in the inactive position, the stiffening blade 35 is inoperative; it does not contribute to stiffening the shell 34 which remains flexible in the bending zone due to the recesses in the bending zone Z and the thin blade-shaped portion 36 (FIG. 15 d).
In the active position, when the shell 34 is bent, the stiffening blade 35 is kept affixed to the blade-shaped portion 36 at the rear of the bending zone Z by the pivot 40. The thickness of the blade-shaped portion 36 doubled by the stiffening blade 35 makes the shell 34 more rigid, making it more difficult to bend the foot (FIG. 15 e).
Thus, the same boot can be used for various practices of Nordic skiing. The stiffening blade 35 is deactivated to obtain a flexurally flexible boot more adapted for the so-called classic practice, and the stiffening blade 35 is activated to obtain a flexurally rigid boot more suited to practice the skating step.
Thus, depending on the position of the end of the stiffening blade 35, the same boot can have a different flexural rigidity. This adjustability is particularly advantageous for example in a competition combining two events, such as a classic event immediately followed by a skating step event without interrupting the timer. This avoids the use of hybrid boots in which rigidity is intermediate between a flexible boot and a rigid boot, and which would be a rather unsatisfactory compromise in both practices. This principle can also be used in mountain boots to make them rigid and to enable crampons to be mounted.
According to a sixth embodiment shown in FIG. 16 a, the ski boot comprises two straight stays 43 connecting the lateral and medial portions of the rear cradle 44 to the lateral and medial portions of the front cradle 45. The portions of the front cradle 45 are defined by the ends of the shell 42 between the upper central recess 8 of the front cradle and the recesses of the bending zone Z. The portions of the rear cradle 44 are defined by the ends of the shell 42 between the upper opening 7 of the recesses of the bending zone Z.
The stays 43 are formed of a strip of fabric made of Kevlar® fibers. The stays 43 are used to prevent the backward bending of the shell 42 and also contribute to the tightening of the shell 42.
According to an alternative embodiment shown in FIG. 16 b, the ski boot comprises a single, generally Y-shaped stay 46. The stay 46 connects the lateral and medial portions of the rear cradle 44 with the front cradle 47. Unlike the previous variation, the front cradle 47 is “solid”, that is to say, it has no upper central recess.
The embodiment proposed in FIG. 17 corresponds to a case in which the boot 1 is devoid of the front cradle. This means that the shell includes only the rear cradle and the blade-shaped portion. Accordingly, the bending zone Z extends from the metatarsus to the front end.
In any case, the invention is made from materials and according to techniques of implementation known to one of ordinary skill in the art.
Naturally, the invention is not limited to the embodiments described above, and includes all technical equivalents that fall within the scope of the claims that follow.

Claims

1. Boot (1), particularly intended for the practice of sports involving gliding on snow or walking, characterized in that it includes an outer shell (2, 2′, 20, 26, 26′, 34, 42) made of a rigid material, the shell (2, 2′, 20, 26, 26′, 34, 42) including a rear cradle (22, 28, 28′, 39, 44) provided to hold the heel of the user, the rear cradle (22, 28, 28′, 39, 44) being extended forward by a blade-shaped portion (6) defining a bending zone, the rear cradle (22, 28, 28′, 39, 44) comprising a peripheral wall (5, 31) and a bottom, the bottom of the cradle and the blade-shaped portion partially defining the sole assembly of the boot, and characterized in that it includes an inner liner (20).

2. Boot (1) according to claim 1, characterized in that the shell (2, 2′, 20, 26, 26′, 34, 42) includes a front cradle (21, 27, 27′, 38, 45, 47), the blade-shaped portion connecting the rear cradle to the front cradle, the blade-shaped portion extending in the area of the metatarsus of a user.

3. Boot (1) according to claim 1, characterized in that the rear cradle and the blade-shaped portion are unitary elements.

4. Boot (1) according to claim 1, characterized in that the rear cradle and the blade-shaped portion are separate elements.

5. Boot (1) according claim 1, characterized in that the thickness of the peripheral wall (5) of the rear cradle is less than 1.5 millimeters.

6. Boot (1) according to claim 1, characterized in that it includes a front cradle, and in that the thickness of the peripheral wall of the front cradle is less than 1.5 millimeters.

7. Boot according to claim 1, characterized in that the thickness (ep) of the blade-shaped portion (6) in the bending zone (Z) is less than 4.0 millimeters.

8. Boot according to claim 1, characterized in that the thickness (ep) of the peripheral wall (5) tapers off between the bottom (6) and the upper opening (7).

9. Boot according to claim 1, characterized in that the minimum width of the bending zone (Z) is at least greater than 5.0 millimeters.

10. Boot according to claim 9, characterized in that the minimum width of the bending zone (Z) is between 20 and 30 millimeters, and is preferably on the order of 25 millimeters.

11. Boot according to claim 1, characterized in that the shell is entirely made of composite materials, and in that the thickness (ep) of the peripheral wall (5) is between 0.5 and 1.2 millimeters.

12. Boot according to claim 11, characterized in that it is made entirely of carbon fibers, and in that the thickness (ep) of the peripheral wall (5) is between 0.5 and 0.8 millimeters.

13. Boot according to claim 11, characterized in that at least the peripheral wall (5) is made of glass fibers, and in that the thickness (ep) of said peripheral wall (5) is between 0.8 and 1.2 millimeters.

14. Boot according to claim 1, characterized in that the blade-shaped portion (6) is made of composite materials, and in that it includes unidirectional fibers of the composite material in the bending zone (Z).

15. Boot according to claim 1, characterized in that the bending zone (Z) defines a front cradle and a rear cradle, the materials of the front and rear cradles being different from one another, the blade-shaped portion (6) being made of carbon fibers.

16. Boot according to claim 1, characterized in that lightening holes are provided in the rear cradle.

17. Boot according to claim 1, taken together with claim 16, characterized in that at least the cradle is made of a plastic material, and in that the thickness (ep) of the cradle is less than or equal to 1.5 millimeters.

18. Boot (1) according claim 1, characterized in that the bending zone (Z) defines a front cradle and a rear cradle, the shell comprising the front cradle and the rear cradle, the shell comprising a means for fixing the front and rear cradles in the area of overlap of the front and rear bottoms of the cradles.

19. Boot (1) according to claim 1, characterized in that the bottom of the rear cradle extends beneath the bottom of the front cradle, the fixing means being arranged beneath the front cradle.

20. Boot (1) according to claim 1, characterized in that the front bottom extends beneath the rear bottom, the fixing means being arranged beneath the rear cradle.

21. Boot according to claim 18, characterized in that the fixing means (33, 33′) is removable.

22. Boot according to claim 1, characterized in that the shell is a unitary element.

23. Boot according to claim 1, characterized in that the shell comprises a stiffening blade (35) extending at least beneath the bending zone (Z), said stiffening blade (35) being adapted to assume an active position in which said stiffening blade (35) thickens the sole assembly in the bending zone (Z), and an inactive position in which the end (37) of the stiffening blade (35) is free.

24. Boot according to claim 23, characterized in that the free end (37) of the stiffening blade (35) extends rearward of the bending zone (Z).

25. Boot according to claim 24, characterized in that the free end (37) of the stiffening blade (35) is adapted to be retained in the active position by a removable retaining means (40).

26. Boot according to claim 1, characterized in that it comprises protective upright panels (12) in the area of the malleoli.

27. Boot according to claim 1, characterized in that the bending zone (Z) defines a front cradle and a rear cradle, and in that the front cradle has a central upper recess (8).

28. Boot according to claim 1, characterized in that the shell comprises through holes adapted to receive fixing screws (11), and in that it comprises inner shoulders arranged around the through holes, adapted to house the heads of said fixing screws (11).

29. Boot according to claim 1, characterized in that the bending zone (Z) defines a front cradle and a rear cradle in the shell (42), and in that the boot comprises two straight stays (43) connecting the walls of the rear cradle (44) to the walls of the front cradle (45), respectively.

30. Ski boot according to claim 1, characterized in that the bending zone (Z) defines a front cradle and a rear cradle in the shell (42′), and in that the boot comprises a Y-shaped stay (46) connecting the walls of the rear cradle (44) to the front cradle (47).