AU2002301963B1

AU2002301963B1 - Thermoplastic sheathing of articles and molding process

Info

Publication number: AU2002301963B1
Application number: AU2002301963A
Authority: AU
Inventors: Ian Pitts
Original assignee: MFG EVOLUTIONS NZ Ltd
Current assignee: MANUFACTURING EVOLUTIONS (NZ) Ltd
Priority date: 2001-11-12
Filing date: 2002-11-12
Publication date: 2003-05-01
Anticipated expiration: 2022-11-12
Also published as: WO2003041945A1

Description

I 12/11 '02 20:28 FAX 61 2 9810 8200 FB. RICE CO. LATE IP AUS [o005 1

AUSTRALIA

Patents Act 1990 MANUFACTURING EVOLUTIONS (NZ) LIMITED COMPLETE SPECIFICATION STANDARD PATENT Invention Title: Thermoplastic sheathing of articles and molding process The following statement is a full description of this invention including the best method of performing it known to us:- 12/11 '02 20:28 FAX 61 2 9810 8200 F.B. RICE CO. LATE IP AUS 1006 1g THERMOPLASTIC SHEATHING OF ARTICLES AND MOULDING PROCESS Field of the Invention The present invention relates to a vacuum forming apparatus and a method which uses the apparatus for applying a thermoplastic membrane in the form of a sheath over an article, particularly an article which includes an undercut which must be sheathed. The present invention also relates to structures formed from expanded polymeric foam which are reinforced and in particular to structures in which reinforced members are embedded therein.

Background Art Vacuum forming has been utilised for many years in order to produce thermoplastic articles of varying shapes, configurations and sizes. More recently attempts have been made to utilise vacuum forming in order to sheath articles, As used in this specification, the formation of a sheath of a thermoplastic material over an article refers to a situation in which the thermoplastic membrane substantially forms a continuous outer coating or skin over the surfaces of an article. In some cases, the thermoplastic membrane may consist of a single continuous sheet that covers the requisite surfaces of an article. In other cases, it may consist of a plurality of membrane sheets that are disposed on the article to provide the requisite degree of surface coverage.

Where an article is sheathed by a vacuum forming process certain problems are encountered as the article itself in effect becomes the mould. For example, the sheathing may be required to undercut the article which process would be precluded in instances where removal of the mould is necessary. In the context of this specification, "undercut" refers to a surface configuration on so an article where the thermoplastic is required to flow down an outer surface, then inwardly around a lower surface and then optionally upwardly over an inner surface. Providing an undercut on the finished article in order to improve its appearance has proved difficult in practice. Sheathing of articles utilising vacuum forming processes has also proved to be difficult where the articles have considerable depth as drawing thermoplastic sheets for relatively large distances usually results in uncontrollable webbing as well as considerable 12/11 '02 20:28 FAX 61 2 9810 8200 F.B. RICE CO. LATE IP AUS i1007 2 wastage of thermoplastic sheet material. It has also proved to be difficult to utilise one vacuum forming machine to simultaneously produce a number of articles requiring a significant depth of draw.

Internal reinforcement members have been utilised for the strengthening and stiffening of expanded polymeric foam structures. Current practice of reinforcement of expanded polymeric foam structures includes the steps of fixing pieces of expanded polymeric foam to reinforcement members with an adhesive so as to form a reinforced structure, or to cut a slot in an expanded polymeric foam structure with a hot knife and glue a reinforcement member within the slot.

Where a structure is reinforced internally using multiple pieces of expanded polymeric foam glued to one or more reinforcement members, or has reinforcement members glued within slots cut within the expanded polymeric foam core, several problems are encountered. One such problem is the bonding of the foam to the reinforcement members. The expanded polymeric foam must be formed or cut so as to be congruent with the geometry of surface of the reinforcement member to which it is to be adhered. Imperfections and defects on either the surface of the foam or the reinforcement member during the cutting or manufacturing process may cause points of weakness resulting in debonding of the foam from the reinforcement member. Complicated crosssections and geometries of multiple arrangements of internal reinforcement members have proven to be extremely difficult to fully adhere foam to whilst still maintaining the overall desired shape of the structure.

A further problem is the reduced overall strength of the foam which results from being formed of more than one piece. Disturbance of and irregularities within the grain structure of the foam at the reinforcement member-foam interface gives rise to failure initiation points.

Another difficulty encountered in reinforcement of expanded polymeric foams after formation of the foam is pre-stressing the structure. Complicated cross-sections and geometries of multiple arrangements of reinforcement members again have proven difficult to achieve whilst maintaining the desired overall geometry and shape of the structure.

Disclosure of the Invention The present inventor has recognised these shortcomings in the prior art and accordingly has sought to provide a vacuum forming apparatus and a method for applying thermoplastic sheathing to articles and the shortcomings of current expanded polymeric foam reinforcement practices in the prior art and accordingly has sought to provide a method of embedding reinforcement members within a expanded polymeric foam core during the process of expanding the polymer.

However it should be noted that any description or reference to the prior art is not an admission that the art forms part of the common general knowledge in Australia.

In a first aspect, the present invention is a method for sheathing an article with a deformable web, the method comprising the steps of: applying at least a first differential pressure to a deformable web in a manner such that a portion of the deformable web is caused to extend through at least one aperture located adjacent a first side.of the sheet to form an extended, bubble like portion having a substantially constant wall thickness, the aperture having a geometry so as to admit an article therein; (ii) relatively advancing the article toward a second side of the deformable web and into the bubble like portion such that the article is located at least partially within the bubble like portion; and (iii) applying at least a second pressure differential across the deformable web, such that air present between the second side of the deformable web and the article is substantially removed and the second side of the deformable web substantially conforms to the surface of the article; wherein the amount of deformable web which extends through the at least one aperture is regulated by the geometry of the at least one aperture.

in an embodiment of the first aspect, the method further comprising the step of applying an adhesive to the surface of the article prior to applying the second pressure differential such that the second side of the deformable web substantially adheres to the surface of the article whilst substantially conforming to the surface of the article. Preferably, the adhesive is selected from the group comprising heat sensitive, heat curing, silicone or pressure sensitive adhesive and heat melt adhesives.

I 12/11 '02 20:29 FAX 61 2 9810 8200 F.B, RICE CO. LATE IP AUS U009 4 In another embodiment of the first aspect and/or any embodiment thereof, the method further comprising the step of at least partially covering the article with a reinforcement material prior to the article being relatively advanced into the aperture of the mechanical assist means.

In a further embodiment of the present aspect and/or any embodiment thereof, the method further comprises the step of applying a design to the article prior to the article being relatively advanced into the aperture of the mechanical assist means. Preferably, the design is selected from the group comprising decorative film, silk screening and holograms. More preferably, the deformable web includes an integral design.

In yet another embodiment of the present aspect and/or any embodiment thereof, the method further comprises the step of reversing the article upon completion of step (iii) and repeating steps (ii) and (iii) such that the article is substantially encapsulated by the deformable web.

In yet a further embodiment of the present aspect and/or any embodiment thereof, the method further comprises the step of removal of portion of deformable web which does not substantially conform to the surface of the article after completion of step (iii). Preferably, the step of removal is performed using mechanical trimming means, a laser cutting means or a fluid cutting means. More preferably, the step of removal is automatically controlled.

In a second aspect, the present invention is a device for sheathing an article with a deformable web, the device comprising: mechanical assist means having at least one aperture relatively positionable adjacent to a first side of the deformable web, the at least one aperture having a geometry so as to admit the article therein; means for providing a relatively greater pressure at a second side of the deformable web, such that a portion of the deformable web is expanded into the at least one aperture in a form of a bubble; means for relatively advancing the article within the at least one aperture of the mechanical assist means such that the article is located at least partially within the at least one aperture and the bubble; means for providing a relatively lower pressure at the first side of the deformable web such that air present between the second side of the deformable web and the article is substantially removed and the second side of the deformable web substantially conforms to the surface of the article; wherein the amount of deformable web which is expanded into the at least one aperture is regulated by geometry of the at least one aperture.

In an embodiment of the second aspect, the device further the device further comprises a means for automatically loading the deformable web in the device.

In a third aspect, the present invention is a sheathed article when made according to the steps of: applying at least a first differential pressure to a deformable web in a manner such that a portion of the deformable is caused to extend through at least one aperture located adjacent a first side of the sheet to form an extended, bubble like portion having a substantially constant wall thickness, the aperture having a geometry so as to admit an article therein; (ii) relatively advancing the article toward a second side of the deformable web and into the bubble like portion such that the article is located at least partially within the bubble like portion; and (iii) applying at least a second pressure differential across the deformable web, such that air present between the second side of the deformable web and the article is substantially removed and the second side of the deformable web substantially conforms to the surface of the article; wherein the amount of deformable web which is caused to extend through the at least one aperture is regulated by the geometry of the at least one aperture.

In an embodiment of the third aspect, the article further comprises a reinforcement means. Preferably, the reinforcement means is a fibre mesh or mat.

In another embodiment of the third aspect and/or any embodiment thereof, the reinforcement means is at least one at least partially internal reinforcement member. Preferably, the reinforcement member is prestressed.

In a further embodiment of the first, second and third aspects and/or any embodiment thereof, the deformable web is formed from a material selected from the group comprising malleable metals, fluoropolymers, reinforced m:\speccomplete\112904soatjI.doc 12/11 '02 20:30 FAX 61 2 9810 8200 F.B. RICE CO. LATE IP AUS 4o011 6 plastics, thermoplastics, thermoset plastics, resin wetted out reinforced cloths, thermoplastic elastomers, timber veneers, polymeric foams and woven cloths.

In yet a further embodiment of the first and second aspects and/or any embodiment thereof, the aperture has geometry greater than that of the greatest geometry the article, the aperture regulating the geometry of the bubble and the amount of deformable web which extends into the aperture.

In still a further embodiment of the first and second aspect and/or any embodiment thereof, the at least first pressure differential is created by air pressure due to the advancing of the article toward the deformable web, by applying hot air at the second side of the deformable web or by applying an at least a partial vacuum at the first side of the deformable web.

In yet another embodiment of the first and second aspects and/or any embodiment thereof, the at least second pressure differential is created by applying at least partial vacuum at the second side of the deformable web.

In still yet a further embodiment of the first and second aspects and/or any embodiment thereof, pressure is applied to the first side of the deformable web in a manner such that the second side of the sheet contacts the article and air present between the second side of the sheet and the article is progressively removed as the second side of the sheet is progressively contacted with the article. Preferably, the pressure is applied to the first side of the sheet by means of a flexible membrane, by means of air pressure or by means of a substantially rigid member effecting pressure mechanically.

In yet still a further embodiment of the first and second aspects and/or any embodiment thereof, the article is supported upon an article support means, the article support means being at least partially air permeable, such that upon application of the at least a second pressure differential, the air present between the deformable web and the article is substantially removed through the article support means, and the sheet at least partially conforms to a surface of the article support means. The article support means has a geometry smaller than the geometry of the article such that the deformable 12/11 '02 20:30 FAX 61 2 9810 8200 F.B. RICE CO. LATE IP AUS 1012 7 web, upon application of the at least a second pressure differential, substantially conforms to the surface of the article so as to form a substantial undercut or the article support means has a geometry larger than the geometry of the article such that the deformable web, upon application of the at least a second pressure differential, substantially conforms to the surface of the article so as to form a substantial overcut.

Preferably, at least a third pressure differential is applied across the deformable web after the deformable web has substantially conformed to the surface of the article, such that the sheathed article is forced from the article support means, more preferably, there being provided fluid communication between the article and the article support means to allow for application of the at least a third pressure differential. More preferably, the article support means provides support for the article such that upon application of the relatively lower pressure at the first side of the deformable web, the article is not substantially deformed.

In further still another embodiment of the first and second aspects and/or any embodiment thereof, an automatic control means is included to provide automatic control of the device and step of the method. Preferably, the control means is a Programmable Logic Controller, a computer or a microprocessor.

In yet still another embodiment of the first, second and third aspects and/or any embodiment thereof, the deformable web is heated prior to applying the at least a first pressure differential by a heating means. Preferably, the deformable web is substantially cooled by a cooling means after the deformable web has substantially conformed to the surface of the article.

In a still yet further embodiment of the first and second aspects and/or any embodiment thereof, the article is formed from a material selected from the group comprising metal, plastics, organic material and rigid gel or an inflatable bladder.

In a preferred embodiment of the first, second and third aspects and/or any embodiment thereof, the article is formed from an expanded polymeric 12/11 '02 20:30 FAX 81 2 9810 8200 F.B. RICE CO. LATE IP AUS 0013 8 material. Preferably, the expanded polymeric material is selected from the group comprising polystyrene, polyethylene, polypropylene and polyurethane.

In a further preferred embodiment of the first, second and third aspects and/or any embodiment thereof, the article is selected from a group comprising surfboards, sailboards, boats, canoes, kayaks, life buoys, fishing net floats, other watercraft, water-safety devices, pontoons, buoyant devices or structures for maritime applications and skis; thermal insulation structures such as coolrooms, saunas, flasks and insulated food and beverage carriers, devices for sound insulation such as panels, doors and roof sections; shock absorption, collision impact, impact resistant and resilient structures such as automobile bumper-bars, mattresses, cushioning devices, body boards, motor sport safety equipment and automobile parts.

In a fourth aspect, the present invention is a method for embedding one or more reinforcement members within an expanded polymeric foam core during a process in which the polymeric material is expanded to produce the foam core comprising the steps of: laying out the one or more reinforcement members within a mould having a shape predetermined to that of the desired structure; (ii) injecting the mould through one or more feed-holes with a predetermined amount of pre-expanded polymeric material containing a compound which on heating expands the polymeric material; and (iii) injecting steam into the mould through a plurality of steam injection holes in a manner so as to cause expansion of the polymeric material into an expanded polymeric foam, thereby embedding the one or more reinforcement members; In an embodiment of the fourth aspect, the method further comprising the step of prestressing the one or more reinforcement members prior to the step of injecting steam into the mould such that the at least one reinforcement member is embedded within the foam core in a prestressed state. Preferably, the at least one reinforcement member is formed from a material selected from a group comprising metals, wood or wood composites, fibre or mesh reinforced polymers, mixed polymer blends, spring steel or other metals or alloys 12/11 '02 20:31 FAX 61 2 9810 8200 F.B, RICE CO. LATE IP AUS []014 9 In another embodiment of the fourth aspect and/or any embodiment thereof, the pre-expanded polymeric material is preferably selected from the group comprising polystyrene, polyethylene polypropylene and polyurethane.

More preferably, the pre-expanded polymeric material further comprises a expansion compound for assisting in expansion of the pre-expanded polymeric material. Preferably, the expansion compound for expansion of the polymeric material when heated is pentane.

In a further embodiment of the fourth aspect and/or any embodiment thereof, the at least one reinforcement member preferably comprises apertures so as to allow the polymeric foam to pass through the at least one reinforcement member during expansion of the polymeric foam.

In a still further embodiment of the fourth aspect and/or any embodiment thereof, the method further comprises the step of sheathing the foam core upon completion of expansion of the pre-expanded polymeric foam. Preferably, the step of sheathing the foam core includes the steps according to the first aspect.

In a fifth aspect, the present invention is a structure having a reinforced foam core when made according to the steps of: laying out the one or more reinforcement members within a mould having a shape predetermined to that of the desired structure; (ii) injecting the mould through one or more feed-holes with a predetermined amount of pre-expanded polymeric material containing a compound which on heating expands the polymeric material; and (ii) injecting steam through a plurality of steam injection holes in a manner so as to cause expansion of the polymeric material into an expanded polymeric foam, thereby embedding the one or more reinforcement members; In an embodiment of the fifth aspect, the one or more reinforcement members is preferably prestressed prior to the step of injecting steam into the mould such that the at least one reinforcement member is embedded within the foam core in a prestressed state. Preferably, the at least one reinforcement member is formed from a material selected from a group comprising metals, wood or wood composites, fibre or mesh reinforced polymers, mixed polymer blends, spring steel or other metals or alloys.

12/11 '02 20:31 FAX 61 2 9810 8200 F.B. RICE CO. LATE IP ATIS IMi015 in another embodiment of the fifth aspect and/or any embodiment thereof, the foam care is formed from a pro-expanded polymeric material selected from the group comprising polystyrene, polyethylene polypropylene and polyurethane.

In a further embodiment of the fifth aspct and/or any embodiment thereof, preferably the structure further comprising an external sheath, wherein the sheath formed from a material selected from a group comprising malleable metals, fluoropolyrners, reinforced plastics, thermoplastics, thermoset plastics resin wetted out reinforced cloths 1 thermoplastic elastomers, timber veneers, polymeric foams, woven cloths. Preferably the sheath is formed according to the method of the first aspect, Preferably the structure according to the fifth aspect and/or any embodiment thereof is selected from a group comprising surfboards, sailboards, boats, canoes, kayaks, life buoys, fishing net floats, other watercraft, water-safety devices, pontoons, buoyant devices or structures for maritime applications and skis; thermal insulation structures such as coolrooms, saunas, flasks and insulated food and beverage carriers, devices for sound insulation such as panels, doors and roof sections; shock absorption, collision impact, impact resistant and resilient structures such as automobile bumper-bars, mattresses, cushioning devices, body boards, motor sport safety equipment, automobile parts In a sixth aspect, the present invention is a method for embedding one or more reinforcement members within a moulded solid polymeric material during the moulding process including the steps of: laying out the one or more reinforcement members within a mould of predetermined shape to that of the desired structure; performing the moulding process; and removing the structure from the mould.

In an embodiment of the sixth aspect, preferably the moulding process is rotation, injection, compression or transfer moulding- 1 12/11 '02 20:31 FAX 61 2 9810 8200 F.B. RICE CO, LATE IP AUS IU016 11 In a further embodiment of the sixth aspect and/or any embodiment thereof, preferably the method further comprises the step of prestressing the one or more reinforcement members prior to the step performing the moulding process such that the at least one reinforcement member is embedded within the moulded solid polymeric material in a prestressed state.

In another embodiment of the sixth aspect and/or any embodiment thereof, the moulded solid polymeric material is selected from a group comprising polystyrene, polyethylene, polyurethane and polypropylene.

In a still further embodiment of the sixth aspect and/or any embodiment thereof, preferably the method further comprises the step of applying an external sheath, wherein the material from which the sheath is formed from is selected from the group comprising an external sheath, wherein the sheath formed from a material selected from a group Comprising malleable metals, fluoropolymers, reinforced plastics, thermoplastics, thermoset plastics, resin.

wetted out reinforced cloths, thermoplastic elastomers, timber veneers, polymeric foams, woven cloths. Preferably, the sheath is applied in accordance with the method of the first aspect In a seventh aspect, the present invention is a moulded solid polymeric material when made according to the steps of: laying out the one or more reinforcement members within a mould of predetermined shape to that of the desired structure; performing the moulding process ;and removing the structure from the mould.

In an embodiment of the seventh aspect, the one or more reinforcement members is embedded within the moulded solid polymeric material in a prestressed state.

In another embodiment of the seventh aspect and/or any embodiment thereof, the moulded polymeric material is preferably selected from a group comprising polystyrene, polyethylene polypropylene and polyurethane.

12/11 '02 20:32 FAX 61 2 9810 8200 F.B. RICE CO. LATE IP AUS 1017 12 In a further embodiment of the seventh aspect and/or any embodiment thereof, the moulded solid polymeric material further comprises a sheath, wherein the material from which the sheath is formed is selected from the group comprising malleable metals, fluoropolymers, reinforced plastics, thermoplastics, thermoset plastics, resin wetted out reinforced cloths, thermoplastic elastomers, timber veneers, polymeric foams, woven cloths.

Preferably the sheath is applied to the moulded solid polymeric material according to the method of the first aspect.

Preferably, the moulded solid polymeric material is selected from a group comprising surfboards, sailboards, boats, canoes, kayaks, life buoys, fishing net floats, other watercraft, water-safety devices, pontoons, buoyant devices or structures for maritime applications and skis; thermal insulation structures such as cool-rooms, saunas, flasks and insulated food and beverage carriers, devices for sound insulation such as panels, doors and roof sections; shock absorption, collision impact, impact resistant and resilient structures such as automobile bumper-bars, mattresses, polycarbonates, polyesters and mixed polymer blends. Alternatively, fibre or mesh reinforced epoxy may be used for coating the structure, depending on the application requirements, In an eighth aspect, the present invention is a sheathed article, wherein the article comprises a deformable web, the deformable web substantially conforming to at least a portion of the surface of the article.

In a ninth aspect, the present invention is a reinforced structure comprising one or more reinforcement members embedded within a single expanded polymeric foam core.

According to the present invention there is provided in a further aspect an apparatus for applying a thermoplastic sheath to an article formed from a substantially non-porous to air material, the apparatus comprising an article support means, a thermoplastic sheet heating means, a clamp means to secure a thermoplastic sheet between the article support means and the heating means, a mechanical assist frame means adjacent an upper side of the thermoplastic sheet, a means to impart a relative motion to the article support means towards the clamp means, the thermoplastic sheet and the mechanical 1 12/11 '02 20:32 FAX 61 2 9810 8200 F.B. RICE CO. 4+ LATE I? AUlS IU018 13 assist frame means, the mechanical assist frame means being adapted to move, without contacting the article, to a sealing position in which the thermoplastic sheet is drawn over a requisite surface of the article, a leading edge of the mechanical assist frame means being adapted to rest in the sealing position against a sealing device being at a location past that point on the article at which the sheathing is to cease, a spacer means interposed between the sealing device and the article support means; the spacer means including one or more galleries which extend from an outer surface thereof contacted by the thermoplastic sheet to an inner surface in communication with an airway, a sealed space bounded by the thermoplastic sheet, the sealing device and external surfaces of the article and being formed when the thermoplastic sheet is in the sealed position against the sealing device, air evacuation means adapted to evacuate air from the sealed space via the airway and one or more galleries, the orientation of the article support means and the spacer means 1s being such that as air is evacuated from the sealed space, the thermoplastic sheet is drawn over the requisite surfaces of the article.

In another aspect, this invention provides a method of sheathing an article formed from a substantially non-porous to air material with a thermoplastic sheet, comprising placing the article to be sheathed on the article support moans and securing a thermoplastic sheet the clamp means, the article support means and the clamp means being Included in an apparatus which comprises: an article support means, a thermoplastic sheet heating means, a clamp means to secure a thermoplastic sheet between the article support means and the heating means, a mechanical assist frame means adjacent an upper side of the thermoplastic sheet, a means to impart a relative motion to the article support means towards the clamp means, the thermoplastic sheet and the mechanical assist frame means, the mechanical assist frame means being adapted to move, without contacting the article, to a sealing position in which the thermoplastic sheet is drawn aver a requisite surface of the article, a leading edge of the mechanical assist frame means being adapted to rest in the sealing position against a sealing device being at a location past that point on the article at which the sheathing is to cease, a spacer means interposed between the sealing device and the article support means; the spacer means 3M including one or more galleries which extend from an outer surface thereof contacted by the thermoplastic sheet to an inner surface in communication with 12/11 '02 20:33 FAX 61 2 9810 8200 F.B. RICE CO. -LATE IP AUS lih 019 14 an airway, a sealed space bounded by the thermoplastic sheet, the sealing device and external surfaces of the article and being formed when the thermoplastic sheet is in the sealed position against the sealing device, air evacuation means adapted to evacuate air from the sealed space Via the airway and one or more galleries, the orientation of the article support means and the spacer means being such that as air is evacuated from the sealed space, the thermoplastic sheet is drawn over the requisite surfaces of the article; activating the heating means so as to cause the thermoplastic sheet to sag, moving the mechanical assist frame means to the sealing position and operating the air evacuation means so as to cause the thermoplastic sheet to be drawn over the requisite surfaces of the article.

In a still further aspect, the present invention provides an article which has been sheathed with a thermoplastic material using an apparatus of the first aspect of the invention or a method of the second aspect of the Invention, It is important to appreciate that the present is useful for both the sheathing of internal and external surfaces of an article. However, each surface must be sheathed in a separate operation and using article support means which are quite different in configuration. Thus, in most instances the article support moans will comprise a mould, the shape and configuration of which should be substantially that of the surface of the article to be sheathed.

Naturally when an internal surface is being sheathed, it will be evident that the mould is a "reverse mould". In this latter case, it is necessary to provide galleries in the article in the requisite areas so that when placed in the mould, these galleries are in air communication with the corresponding galleries in the spacer means. These requisite areas will usually be those in which there is any change in surface details such as the edge where adjacent surfaces meet.

Given the substantial force that is exerted on the mould owing to the large differential pressure formed when air is evacuated, it is important that the mould is constructed wiith appropriate strength. Such moulds may be formed from conventionally used materials such as aluminium filled epoxy resin or cast aluminiumr. These moulds must also be formed so as to allow for the incorporation of galleries, If required. Thus in those embodiments were the external surface of the article to be sheathed includes a change in surface 12/11 '02 20:33 FAX 61 2 9810 8200 F.B. RICE CO, LATE IP AUS [1020 details, it is necessary to include galleries in the mould so that the air in that detail may be drawn out, thereby causing the thermoplastic sheet to adopt the surface detail. Generally, these galleries will be additional to those required in the spacer and like the spacer, the galleries will be in air communication with the airway.

Significantly, sheathing may be accomplished over surface details such as the embossing of alphanumeric characters on a surface. In these and other like instances, it is likely to be necessary to include galleries in the form of a plurality of fine grooves arrayed in the surface of the mould around the detail and extending through the mould so as to be in air communication with the airway. Positioning of these grooves will in some cases be critical to ensure that correct sheathing is obtained. Typically, the grooves may be 0.5 to 1 mm in width. In addition, it may be necessary to use galleries which extend through is the mould and into or near the detail in conjunction with the aforementioned grooves to obtain correct sheathing.

Whilst a variety of thermoplastic materials may be used for the sheathing, amorphous plastics materials are preferred. Such amorphous materials are suitable as they undergo sagging when heated. Examples of thermoplastic materials include PETG, APET, high impact styrene, ABS, polycarbonates, polyesters and polycarbonatelpolyester alloys. Usually the thermoplastic material will be chosen so as to provide the characteristics required in the sheathed article.

Thus amongst the uses of thermoplastic sheathing may be mentioned those in which there is substantial exposure to water. In this case articles may include buoys, floats for fishing nets, life preservers and water craft such as surfboards, body boards and dinghies. These articles would usually be formed from a lightweight blank which would then be sheathed completely. In this way the finished article would be waterproof.

For articles such as body boards, sheathing would be performed in two operations. Thus a first sheet of thermoplastic would be sheathed over an upper surface and extending around the curved edges of the board. A second sheet of thermoplastic would then be sheathed over the remaining under 1 12/11 '02 20:33 FAX 61 2 9810 8200 F.B. RICE CO. 4+ LATE IP AUS 02 186 surface so as to provide a complete coverage. In these instance, it is desirable to form a small groove which extends around the under surface adjacent the curved edge of the board in the body board blank. This groove would form a region in which the two sheets met and would function to avoid any overlap between the sheets.

It Will Of Course be appreciated that in some cases where two separates sheets of thermoplastic are used, they may be formed from different thermoplastic materials. This may be desirable whore it is important that ao different surfaces which are to be sheathed by these materials are required to have different properties. For example, the under surface of a body board should be abrasion resistant and have low frictional properties in the water. By contrast, the upper surface does not require such properties.

Whilst in general terms sheathing of an article results in an intimate covering of a surface, to further improve bonding, an adhesive may be used between the article and the thermoplastic sheet. Usually a thermosetting adhesive would be used. In this way, properties such as resistance to mechanical damage and water resistance would be improved.

Furthermore, it is within the scope of the invention to provide an additional coating to the thermoplastic sheathing. For example, in some applications involving outdoor use, polyurethane may be added as a coating, optionally with UV stabilisers and absorbers.

As previously mentioned, a vacuum is drawn in order to withdrew the air, particularly from around surface detail changes and between the thermoplastic sheet and the article once the sealing position is reached- This evacuation of air must occur reasonably quickly so it is important that an adequate vacuum pump is used. Indeed, it is preferred to use intermediate vacuum cylinders in order to achieve the requisite degree of evacuation in a suitable time frame.

Generally, once evacuation has occurred, the vacuum would be held whilst the thermoplastic is cooled. Once cool, the air may be pumped back through the airway and galleries thereby resulting in the article being blown off the mould, 12/11 '02 20:34 FAX 61 2 9810 8200 F.B. RICE CO. LATE IP AUS Q 022 17 Examples of article formed using the method according to the second aspect include office partitioning, machinery sound cabinets, ducting, tubing, commercial cool rooms, commercial freezers, dangerous goods containers, portable buildings, low cost housing, sterilisers, fluid vessels, replacement for metal vessels, waterproof transport containers, aircraft flooring, form ply replacement, insulated vegetable boxes, insulated seafood boxes, reuseable packaging, liquid transport containers, ammunition boxes, computer hardware transport containers, refrigerator cabinets, freezer cabinets, coolers, portable refrigerators ,domestic cool rooms, water heaters, outdoor furniture ,outside and inside walls for buildings, buildings floors and ceilings, roof tiles with or without inbuilt solar panels, door jambs and doors, automotive bumpers, dash panels, protective panel inserts, mobile homes and caravan components, lifts rafts, life preservers, yacht tenders, small boats, sailing dinghies, hatch covers, boat seats, boat furniture, surf boards, body boards, wind surfers, snow boards, industrial safety helmets, motor cycle helmets, bicycle helmets and sporting cross over helmets It is important to appreciate that the present invention is useful for reinforcing expanded polymeric foams with embedded reinforcement members during the process of expanding the pre-expanded polymer, thus resulting in a foam core which is completely congruent with the geometries and shapes of the reinforcement members. The resulting foam structure has a more uniform grain structure at the interface of the foam-member interface. The bond at the interface is formed by the expanded polymeric foam melting to the reinforcement members and from the foam flowing into the topography of the member, resulting in a complete mechanical interlock. The reinforcement members may have one or more apertures or recesses to allow foam to flow through or around during the expansion process. The reinforcement members may be designed to take a variety of loads likely to be encountered by the structure including tension, compression, bending, torsion and shear loads.

The reinforcement members may be made from metals, wood or wood composites, fibre or mesh reinforced polymers, mixed polymer blends, spring steel or other metals or alloys, other reinforcement materials, depending on environmental, strength and weight requirements. Joining sections and cross- 12/11 '02 20:34 FAX 81 2 9810 8200 F.B. RICE CO. LATE IP AUS I1023 18 linking mechanisms may be used to allow ease of lay-up and strengthening of the reinforcement members.

Importantly, the method of embedding the reinforcement members within a polymeric foam core allows the members to be laid up prior to the polymeric foam being expanded within the mould which is made to the shape of the required finished structure. An advantage of this method is that the resulting foam structure consists of a single foam core which, on removal from the mould, is the required shape and requires no further working.

A further important advantage of this method is that the members may be laid up in the mould in a pre-stressed state prior to the foam being expanded so that, on removal from the mould, the finished structure is in a pre-stressed state, such that the structure may resist impact loads, may provide dampening and load absorption under impact and provide elasticity to the structure.

The reinforcement members are arranged in a pre-determined geometrical configuration, depending on the loading requirements of the structure, within the mould. The mould is of a two-part structure and may be made from aluminium, or any other suitable material for making such a mould.

A pre-determined amount of pre-expanded polymeric material is injected through one or more feed-holes which pass through the mould, flowing through and around the reinforcement members. An example of a material suitable for use is polystyrene with a compound included which, when heated, causes the expansion of the polymeric material. An example of such a compound is pentane. Examples of other suitable materials are polyethylene or polyurethane, which may be expanded through a chemical reaction. Steam is injected through a plurality of steam injection holes through the mould, heating the compound for a suitable duration of time, resulting in an expanded 3D polymeric foam. The reinforced polymeric structure is then removed from the mould, and further processing, including coating may be performed, depending on the application.

In another embodiment of the invention, the structure may be a body board for the use in wave surfing. The reinforcement members are made from a fibre reinforced polymer arranged in a configuration so as to strengthen and 12/11 '02 20:34 FAX 61 2 9810 8200 F.B. RICE CO. LATE IP AUS I024 19 reduce the amount of flexing of the structure. The reinforcement members may be manufactured with apertures so as to allow the polymeric foam to pass through the members during the expansion process and reduce weight. Small polymeric spacers are used in a manner such that the reinforcement members do not touch the internal surface of the mould, allowing the polymeric foam to flow over and below the reinforcement members. Inserts may also be included for rope or fin attachment. The inserts may be attached to or part of the reinforcement members. The polymer used for the core of the body board may be expanded polystyrene (EPS). The core of the structure is then coated with a waterproof and abrasion resistant polymeric coating. A preferred coating for the structure is a thermoplastic sheath, the method used as described in the first aspect. Examples of the thermoplastics to be used include PETG, APET, high impact styrene, ABS, polycarbonates, polyesters and mixed polymer blends. Alternatively, fibre or mesh reinforced epoxy may be used for coating the structure, depending on the application requirements.

In a further embodiment of the invention, the structure is a life buoy for water safety applications. The reinforcement members are made from a polymeric compound and arranged in a pre-stressed state prior to being embedded in an expanded polymeric foam in a manner such that structure has impact resilience. Alternatively the members may be pre-stressed by being press-fitted into the mould. The polymer used for the core is expanded polystyrene (EPS). The core of the structure is then coated with a waterproof and abrasion resistant coating. A preferred coating for the structure is a thermoplastic sheath, the method used as described in the first aspect.

Further examples of the invention include surfboards, sailboards, boats, canoes, kayaks, life buoys, fishing net floats, other watercraft, water-safety devices, pontoons, buoyant devices or structures for maritime applications and skis; thermal insulation structures such as cool-rooms, saunas, flasks and insulated food and beverage carriers, devices for sound insulation such as panels, doors and roof sections; shock absorption, collision impact, impact resistant and resilient structures such as automobile bumper-bars, mattresses, cushioning devices, body boards, motor sport safety equipment, automobile parts. The outer layer or coating of the structure may be a polymer, a fibre reinforced polymer, a metal or another coating material.

12/11 '02 20:35 FAX 61 2 9810 8200 F.B. RICE CO. LATE IP AUS Z]025 In order to better understand the nature of this invention, several embodiments will now be described with reference to the accompanying drawings.

Brief Descriotion of the Drawinas Figure 1 is a cross-sectional schematic view of an apparatus illustrating io the method in accordance with the present invention; Figure 2 is a cross-sectional schematic view of an apparatus illustrating the method in accordance with the present invention showing undercut; Figure 3 is a cross-sectional schematic view of an apparatus illustrating the method in accordance with the present invention showing overcut; Figure 4 is a cross-sectional view of the apparatus according to Figures 1-3 including a pressurisation device.

Figure 5 is a cross-sectional view of an apparatus in accordance with the present invention; Figure 6 is a plan view of the mechanical assist frame means of the apparatus of Figure Figure 7 is a cross-sectional detail of the thermoplastic sheet, article, spacer device and sealing device intersection of the apparatus of Figure Figure 8 is a top plan view of the spacer device of the apparatus of Figure 1; Figure 9 is a side elevation of the spacer device of Figure 8; Figure 10 is a part cross-section through A-A' of the spacer device of Figure 8; Figure 11 is a cross-sectional view of a second article sheathed on an inner surface; Figure 12 is a cross-sectional view of the second article sheathed on an outer surface; Figure 13 is a cross-sectional view of a third article positioned just prior to sheathing; and Figure 14 is a cross-sectional view of a fourth sheathed article.

Figure 15 is a partial sectional of a device in accordance with the present invention: 12/11 '02 20:35 FAX 61 2 9810 8200 F.B. RICE CO. LATE IP AUS 0026 21 Figure 16 is a further view of the device of Figure Figure 17 is a further view of the device of Figure 16; Figure 18 is an enlarged view of a portion of the device of Figure 17; Figure 19 is a plan view of examples of reinforcement members for body boards, with joining members disposed at the junctions of the members; Figure 20 is a side view of an example of a reinforcement member showing apertures through the member and cross-linking members; Figure 21 is a sectional view of an example of a reinforcement member shoring location of apertures and cross-linking members; Figure 22 is a plan view of a body board with two embedded reinforcement members arranged in a parallel longitudinal configuration; Figure 23 is a plan view of a body board with embedded reinforcement members arranged in a Y-shape configuration; Figure 24 plan view of an example of a reinforced life buoy showing location and geometry of pre-stressed reinforcement members; Figure 25 is a view of a joining method for joining reinforcement members; and Figure 26 is an elevation sectional view through the example of a reinforced life buoy in Figure 24.

Best Mode of Performing the Invention in the description that follows, like features in each drawing have been like numbered.

In Figure 1 there is depicted schematically an apparatus 10 for sheathing an article 5 with a deformable web 2. A mechanical assist means 1 is included having an aperture 6. As shown in the mechanical assist means 1 is located adjacent a first side 3 of the deformable web 2. The deformable web 2 is a sheet of material having structural properties such that the deformable web 2 can extent into the aperture 6.

A first pressure differential is applied to the deformable web 2 such that at least a portion of the deformable web 2 is caused to extend into the aperture 6 as shown in The pressure differential applied to the deformable web 2 can be effected by applying a higher pressure at the second side of the 12/11 '02 20:35 FAX 61 2 9810 8200 F.B. RICE CO. LATE IP AUS I[027 22 deformable web 4 or by applying a lower pressure at the first side 3 of the deformable web 2 for example by applying at least partial vacuum. The deformable web 2 extends in the form of a bubble 7 at least partially within the aperture 6. The aperture 6 of the mechanical assist means 1 is of shape and size such that sufficient clearance is provided so that the article 5 will pass into the bubble 7. The mechanical assist means I allows to forming of a bubble 7 by the deformable web 2, the bubble 7 having substantially constant wall thickness. The mechanical assist means 1, by having the aperture 6 appropriately sized for the required article, limits the amount of deformable web 2 which is used to form the bubble 7.

The article 5 to which the deformable web 2 is to be substantially conformed to the surface of is advanced such that it is positioned at least partially within the bubble 7 as shown in (iii). In this example, the article 7 is positioned wholly within the bubble 7.

A second pressure differential is applied to the deformable web 2 such that air present between the article 5 and the second side 4 of the deformable web 2 is removed and the deformable web 2 substantially conforms to the surface of the article 5 as shown in The second pressure differential can be effected by applying a lower pressure, for example partial vacuum, at the second side 4 of the deformable web 2, or by applying a pressure greater than the pressure at the second side 4, at the first side 3 of the deformable sheet Figure 2 illustrates steps to provide an undercut 8 of deformable web 2 at the lower side of an article 5 and means for doing so. Steps and (ii) replicate those as discussed in Figure 1. In order to effect undercut, there is provided an article support means 12 against which the article 5 is abutted.

The article 5 to which the deformable web 2 is to be substantially conformed to the surface of, is advanced such that it is positioned within the bubble 7 as shown in (iii). An article support means 12 is provided and is in communication with the article 5. In this example, the article support means 12 is positioned such that contact is made at 9 between the deformable web 2 and the article support means 12 and a chamber 11 is formed, the chamber being defined by the second side 4 of the deformable web 2 in the bubble portion 7, 12/11 '02 20:36 FAX 61 2 9810 8200 F.B. RICE CO. LATE IP AUS 1028 23 the surface of the article 5 to which the deformable web is to be conformed to and a portion of the article support means 12. The article support means is at least partially fluid permeable such that when the second pressure differential is applied, air is removed from the chamber 11 region.

As shown in air has been removed from the chamber 11 due to the second pressure differential, and the deformable web is substantially conformed to the surface of the article 5. A suitable manner in which to apply the second pressure differential includes applying at least a partial vacuum to the article support means 12 which in turn provides a second pressure differential at the second side 4 of the deformable web 2. The undercut 8 is formed as the deformable web 2 is deformed and drawn toward the article support member.

Figure 3 illustrates steps to provide an overcut 13 of deformable web 2 at the article 5 and means for doing so. Steps and (ii) replicate those as discussed in Figure 1.

The article 5 to which the deformable web 2 is to be substantially conformed to the surface of, is advanced such that it is positioned within the bubble 7 as shown in (iii). The article support means 12 is provided and is in communication with the article 5. In this example, the article support means 12 is positioned such that contact is made at 9 between the deformable web 2 and the article support means 12 and a chamber 11 is formed, the chamber being defined by the second side 4 of the deformable web 2 in the bubble portion 7, the surface of the article 5 to which the deformable web is to be conformed to and a portion of the article support means 12. The article support means is at least partially fluid permeable such that when the second pressure differential is applied, air is removed from the chamber 11 region.

As shown in air has been removed from the chamber 11 due to the second pressure differential, and the deformable web is substantially conformed to the surface of the article 5. A suitable manner in which to apply the second pressure differential includes applying at least a partial vacuum to the article support means 12 which in turn provides a second pressure differential at the second side 4 of the deformable web 2. The overcut 13 is 12/11 '02 20:36 FAX 61 2 9810 8200 F.B. RICE CO. LATE IP AUS I029 24 formed as the deformable web 2 is deformed and drawn toward the article support member.

The method as described with reference to Figures 1-3 is used for s materials in sheet form having structural properties to allow the forming of the bubble 7. Suitable such materials include malleable metals, fluoropolymers, reinforced plastics, thermoplastics, thermoset, plastics, resin wetted out reinforced cloths, thermoplastic elastomers, timber veneers, polymeric foams, woven cloths. The mechanical assist means 1 controls the amount of material deformed by the first pressure differential, whereby upon application of the second pressure differential and sheathing of the article 5, "webbing" or "puckering" of excess material is substantially reduced or eliminated due to the amount of material which is used in the process being controlled or limited by the mechanical assist means.

A further step of heating the deformable web 2 can be included prior to the first pressure differential being applied to facilitate increased ease of forming of the bubble 7. An adhesive may applied to the surface of the article to increase bonding between the deformable web 2 and the surface of the article 5. Suitable such adhesives include heat sensitive adhesives, heat curing adhesives, silicon or pressure sensitive adhesive and heat melts.

Figure 4 shows across sectional view of the device as described in Figures 1-3, further including an example of a pressurisation device 20 for applying pressure to the first side 3 of the deformable web 2 such that the second side 4 of the deformable web contacts the article 5 and air present between the second side 4 of the deformable web 2 and the article is progressively removed as the second side of the deformable web is progressively contacted with the article In this example, in addition to the second pressure differential, a third pressure differential is applied to the deformable web 2 by a flexible membrane 21. As illustrated in the flexible membrane 21 is urged toward the first side 3 of the deformable web by a third pressure differential and is arranged so as to deform and contact the first side 3 of the deformable web 2 and to urge the 12/11 '02 20:36 FAX 61 2 9810 8200 F.B. RICE CO. LATE IP AUS @030 deformable web 2 such that initial contact is made between the second side 4 of the deformable web 2 and the article 5. The flexible membrane 21 is further urged by the third pressure S differential as shown in (ii) such that the deformable web is progressively urged against the article 5, progressively causing air present between the second side 4 of the deformable web and the article to be removed.

Further increased pressure upon the first side 3 of the deformable web by the flexible membrane 21 causes further removal of air as shown in (iii) until the deformable web 2 substantially conforms to the surface of the article as shown in (iv).

The use of such a pressurisation device assists in removal of air from articles 5 have non-uniform surface topography and irregular geometries. In particularly, the process as described in Figure 4 is effective when an adhesive is applied to the surface of the article 5 in assisting in removal of air.

In Figure 5 there is depicted an example of a sheathing apparatus 30 in accordance with the present invention comprising clamping means 31 adapted to clamp sheet of deformable web 32 in a planar orientation above articles on article support means 34. In this instance the articles 40 are open headed insulated containers shown in an inverted position over the article support means 34, the insulated containers being manufactured from expanded polystyrene.

It will be observed that the articles 33 are contained in a chamber bounded by the deformable web 32, the deformable web in this example being a thermoplastic sheet, box slides 36 and a lifting plate 37. On the underside of lifting plate 37 there are two rams 38 adapted to move lifting plate 37 upwardly so as to urge articles 33 towards thermoplastic sheet 32 and to return the lifting plate 37 to the position shown in the drawing.

A heater box 39 is positioned immediately above the thermop[astic sheet 32 and is adapted to heat the entire apparatus 30 and particularly thermoplastic 12/11 '02 20:37 FAX 61 2 9810 8200 F.B. RICE CO. LATE IP AUlS Z~031 26 sheet 32. A mechanical assist means 41 is disposed intermediate the heater box 39 and the thermoplastic sheet 32.

This mechanical assist means 41 is better viewed in top plan configuration from Figure 6. It will be appreciated from Figure 8 that the mechanical assist means 41 is adapted to pass down over the upper extremities 33 of articles 34 when the articles are urged up to and past mechanical assist means 41 by the rams 38 and that the mechanical assist means 41 is adapted to clear the sides of articles 40. The frame is adapted to come to rest (after the rams 38 have reached their maximum stroke) against sealing device 42 in order to achieve the sealed position of the apparatus. At the sealed position depicted in Figure 7, the thermoplastic sheet 32 is interposed between the frame 41 and the sealing device 42 whereas the clamp 43 lies beneath the upper surface of the sealing device 42 s0 that the sheet 32 as is wrapped around the edge 44 of sealing device 42 so as to assist in forming an airtight seal.

It will be appreciated that before the rams 38 are operated to advance the articles 40 up and through the mechanical assist means 41, the heater box 39 is moved from the position depicted in Figure 5 in order to provide the necessary clearance.

In order to ensure that the heated thermoplastic sheet 32 contacts articles 40 and adheres thereto, air is evacuated from the area between the articles and the sheet 32 through peripheral passages 45 in spacer 46.

The configuration of spacer 46 is best seen in Figures a, 9 and 10 where it will be observed from Figure 8 that in plan view, these peripheral air passages 45 lead from the peripheral edges of the rectangular shaped spacer to manifold air galleries 47 and eventually to evacuation outlet 48 in the base of the spacer 46.

It will be appreciated that by uitilisation of a spacer 46 in accordance with Figures 8, 9 and 10 located as depicted in Figure 7, it is possible to wrap the thermoplastic sheet 32 around the edge 49 of the articles 40 so as to effectively form an undercut 51 with respect to the articles 40- It must be appreciated that 12/11 '02 20:37 FAX 61 2 0810 8200 F.B. RICE LATE IP AUTS 111032 27 when sheathing an article, the article itself is the mould, As such the sheath is not really an undercut although the terminology "undercut" arises due to an analogy with conventional vacuum forming technology where such an undercut would not be possible due to the necessity to remove the mould from the vacuum formed article. The last mentioned ability to finish around the edge of an article by way of formation of said undercut is particularly advantageous and a feature which has proven to be difficult to achieve with prior art apparatus and methods.

It should further be appreciated that the present apparatus and method does not rely on air permeability of the article itself In Figure 11 there is shown a second article 50 which has been sheathed on an inner surface thereof with a thermoplastic sheet 52. In this embodiment, this has been accomplished through the use of a mould 53 in which galleries 54 have been provided to evacuate air from the inner corners 55 of the article as well as from the outer surfaces 56 of the article. Each of the galleries 54 is in air communication with airway 48 so as to facilitate evacuation. Additionally, galleries 57 have been provided in the article 50 at corners 55 so that these galleries are in air communication with the corresponding galleries 57 in the mould. A mould support 58 is also provided.

In Figure 12, there is shown a second article 60 which has been sheathed on an outer surface thereof with a thermoplastic sheet 61. In this embodiment, this has been accomplished through the use of a mould Galleries 62, 63 and 64 have been provided in a mould support 66 so as to facilitate evacuation of air. These galleries hive been provided in areas where there is a change in surface detail so as to ensure that the thermoplastic sheet conforms with surface detail.

In Figure 13, there is shown a third article 70 which is to be sheathed with a thermoplastic sheet 32. In this embodiment, the outer surfaoe detail of the article 70 is relatively complex. Thus there are a number of grooves in the surface which must be provided with galleries to ensure that the air is withdrawn from the groove thereby allowing the thermoplastic sheet to sheath around the detail- For example, the base 73 of one groove is provided with a 1 12/11 '02 20:37 FAX. 61 2 9810 8200 F.B. RICE CO. LATE IP AUlS 14]033 28 single gallery 16 whilst: a second groove having two inner edges 74 and 75 is provided with galleries 77 and 78 respectively. All of the galleries formed in the article 70 are in air communication with corresponding galleries 71 which are formed in the mould support 72. Galleries 71 lead into airway 48 which is in turn connected to a vacuum pump.

There is shown a fourth article 80 in Figure 14 which is a toroid. In this embodiment, the article 80 comprises a blank 82 which has been sheathed with a thermoplastic sheet to cover all surfaces 83, 84 and 85. In addition, the sheet has been extended so that one of the circular open ends of the toroid has been sheathed by the sheet at 81.

The apparatus depicted in Figures 5 10 hereof is suitable for use in conjunction with articles having concavities in their upper extremities provided profile lines leading down the sides of the articles are provided in order that air may be evacuated. The apparatus and method of the present invention has been found to be particularly useful in relation to thin articles of very low density which articles would normally be too soft to be durable. The addition of a thermoplastic sheath gives such an article considerable extra strength and serviceability particularly as the heat of the process tends to bond a thermoplastic sheath to an article of say expanded polystyrene.

Apparatus in accordance with the present invention may furthermore be modified so as to suit articles in reiation to which a partial sheathing is required.

If for example it was required to sheath the upper extremity of an article but not the lower of an article then such article could be recessed into sealing device 42.

It has been found that apparatus of the present invention is particularly useful where amorphous thermoplastic sheets are used as the sheets will draw better down the sides of deep articles. Apparatus in accordance with the present invention allows far deeper draw than is normally possible with conventional vacuum forming technology. When conventional vacuum forming technology is utilised in order to try and draw a sheath over a deep article webbing will occur in the thermoplastic sheet which effectively destroys the finish dlown the side of the article and/or wastes a large amount of material.

12/11 '02 20:38 FAX 61 2 9810 8200 F.B. RICE CO. 4 LATE IP AUS Q1034 29 Amorphous polyethylene terepthalate (APET) has been found to be particularly useful and such APET sheets of approximately 0.5 mm thickness have been drawn down over 320mm deep utilising a frame to article clearance of about five mm. Nine rectangular shaped articles of approximately the last mentioned dimensions have been simultaneously sheathed utilising apparatus as depicted in Figure 5 and a frame as depicted in Figure 6. Ideally such an APET sheet should be heated to around 140 0 C whereas the frame should be 40-50°C cooler than the sheet.

It should be appreciated that alternate embodiments of the present invention apart from the above described may be devised without departing from the spirit and scope of the present Invention. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

In particular it will be appreciated that the frame may be advanced towards the article rather than vice versa and of course the article may be of many configurations apart from rectangular.

Figure 15 shows a partial sectional view of a device 90 for sheathing an article 96 with a deformable web, in accordance with the present invention. A thermoplastic sheet 91 is suspended in the device 90 between support members 92. The thermoplastic sheet 91 is clamped to the support members 92 by a clamping means 99. A heating means 93 is located adjacent the thermoplastic sheet 91 such that the sheet is heated to a temperature at which the thermoplastic 91 sheet can at least partially plastically deform.

As shown in Figure 16, an article 96 to be sheathed is advanced toward the thermoplastic sheet 91. A bed member 95 is used to advance the article 96- The bed member 95 can be advanced by mechanical, pneumatic or hydraulic means. As the bed member 95 advances toward the heated thermoplastic sheet 91, the heating means 93 is removed and the thermoplastic sheet 91 extends through an aperture 101 in a mechanical assist means 94. Air pressure due to the bed member 95 being advanced causes the thermoplastic sheet 91 to form a bubble 102. Channels 103 in fluid communication with the lower side of the thermoplastic sheet 91 are used to regulate the pressure and control the size of the bubble 102.

12/11 '02 20:38 FAX 61 2 9810 8200 F.B. RICE CO. LATE IP AUS l1035 Figure 17 illustrates the article 96 located within the bubble 102 of the thermoplastic sheet 91 when the bed member 95 has fully advanced such that the thermoplastic sheet 91 is urged toward the mechanical assist means 94.

The outer edge 104 of the bed member 95, when driven into the heated thermoplastic sheet 91, forms a seal such that a vacuum pump 98 can perform the step of withdrawing air between the thermoplastic sheet 91 and the article 96 in accordance with the present invention. This is achieved by the article being supported by an article support means 97 which is at least partially porous to air and in fluid communication with the vacuum pump 98. It will be appreciated that such a method of effecting a seal is example of one manner in which to effect such a seal- An enlarged view of the seal caused by the outer edge 104 of the bed means 95 is shown in Figure 18? whereby the underside of the thermoplastic; sheet 91 is urged against the outer edge 104.

It must be understood that the aperture 101 of the mechanical assist means 94, by being appropriately sized such that the item 96 can pass through, regulates the amount of material of the thermoplastic sheet 91 which extends into the bubble 102. By having the amount of material controlled, upon application of the vacuum pump 98, as the thermoplastic sheet conforms to the surface of the article 96 in accordance with the invention, the amount of excess thermoplastic sheet is substantially reduced, allowing for substantial reduction or removal of "webbing" or "Ipuckering"~ caused by excess thermoplastic sheet 91 as the sheet is conformed to the surface of the article. Appropriate sizing of the aperture in relation to the size of the article is important in minimising 'Webbing". For example, when sheathing an article such as a bodyboard, an aperture having a perimeter of about 20 mm greater than the outer perimeter of such a bodyboard substantially reduced the amount of "webbing".

Typical configurations of reinforcement members for body board reinforcement are shown in Figure 19. Junction couplings 121 may be used to loin the reinforcement members 122 in the pro-determined configuration, An example of a reinforcement member 122 is shown in Figures 20 and 21. The reinforcement members 122 may have cross beams 123 extending 12/11 '02 20:39 FAX 61 2 9810 8200 F.B. RICE CO. 4 LATE IP AUS U1036 31 perpendicular from their longitudinal axes for cross-linking between reinforcement members to increase rigidity. Apertures 12 may be provided in the reinforcement members 122 so as to reduce the weight of the member and to allow flow-through of a expanded polymeric foam.

Shown in Figure 22 is a typical configuration of a body board 130 reinforced with two parallel reinforcement members 131. The core of the body board is an expanded polymeric foam, expanded around and through the reinforcement members 131 in a manner as described previously such that the io members 131 are embedded within the foam core. The body board 130 is then coated with an appropriate thermoplastic material or reinforced polymer layer as described in accordance with the present invention.

A further example of a reinforced body board 140 is shown in Figure 23.

Multiple reinforcement members 141 are used for reinforcement and joined with a junction coupling 142. The core of the body board 140 is made from an expanded polymeric foam using the same processes as described in accordance with the present invention such that the reinforcement members 141 are embedded within the foam core. An appropriate coating is applied to the body board as described in accordance with the present invention.

An example of a life buoy 150 which uses an internal pre-stressed reinforcement configuration is shown in Figure 24. Hoop reinforcement members 151 are made from straight members looped around and joined with a coupling 152 such that a pre-load is created within the member- Radial reinforcement members 153 are used to permanently lock and space the hoop reinforcement members 151. An example of a method of locking the hoop 151 and radial 153 members together is shown in Figure 25 whereby notches 154 in the reinforcement members are used as a locating mechanism. The prestressed reinforcement structure is placpd inside an appropriately shaped mould.

Small spacers 156, as shown in Figure 26, are used so as to locate the reinforcement members in a manner such that the members are not in contact with the internal surface of the mould. The core 155 of the life buoy 150 is formed by expanding a polymeric foam as described in accordance with the I 12/11 '02 20:39 FAX 61 2 9810 8200 F.B. RICE CO. LATE IP AUS 037 32 present invention. On removal from the mould, the life buoy 150 is coated with an appropriate material using a process as described in accordance with the present invention to form a waterproof skin. A ring of a rubber-like material such as silicon may be stretched around the finished buoy and located in a groove made during manufacture of the buoy 150 so as to provide a impact absorbing buffer 157. This buffer 157 may be hollow so as provide deformation during impact.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

1. A method for sheathing an article with a deformable web, the method comprising the steps of: applying at least a first differential pressure to a deformable web in a manner such that a portion of the deformable web is caused to extend through at least one aperture located adjacent a first side of the sheet to form an extended, bubble like portion having a substantially constant wall thickness, the aperture having a geometry so as to admit an article therein; (ii) relatively advancing the article toward a second side of the deformable web and into the bubble like portion such that the article is located at least partially within the bubble like portion; and (iii) applying at least a second pressure differential across the deformable web, such that air present between the second side of the deformable web and the article is substantially removed and the second side of the deformable web substantially conforms to the surface of the article; wherein the amount of deformable web which extends through the at least one aperture is regulated by the geometry of the at least one aperture.

2. The method according to claim 1, wherein the deformable web is formed from a material selected from the group comprising malleable metals, fluoropolymers, reinforced plastics, thermoplastics, thermoset plastics, resin wetted out reinforced cloths, thermoplastic elastomers, timber veneers, polymeric foams and woven cloths.

3. The method according to claim 1 or 2, wherein the aperture has a circumference and geometry greater than that of the greatest geometry the article, the aperture regulating the geometry of the bubble and the amount of deformable web which extends into the aperture.

4. The method according to any one of claims 1 to 3, wherein the at least first pressure differential is created by air pressure due to the advancing of the article toward the deformable web. m:\specicomplete\112904soatjl.doc The method according to any one of claims 1 to 3, wherein the at least first pressure differential is created by applying hot air at the second side of the deformable web.

6. The method according to any one of claims 1 to 3, wherein the at least first pressure differential is created by applying an at least a partial vacuum at the first side of the deformable web.

7. The method according to any one of claims 1 to 6, wherein the at least second pressure differential is created by applying at least partial vacuum at the second side of the deformable web.

8. The method according to any one of claims 2 to 7, further comprising the step of applying pressure to the first side of the deformable web in a manner such that the second side of the sheet contacts the article and air present between the second side of the sheet and the article is progressively removed as the second side of the sheet is progressively contacted with the article.

9. The method according to claim 8, wherein the pressure is applied to the first side of the sheet by means of a flexible membrane. The method according to claim 8, wherein the pressure is applied to the first side of the sheet by means of air pressure.

11. The method according to claim 8, wherein the pressure is applied to the first side of the sheet by means of a substantially rigid member effecting pressure mechanically.

12. The method according to claim any one of claims 8 to 11, further comprising the step of applying an adhesive to the surface of the article prior to applying the second pressure differential such that the second side of the deformable web substantially adheres to the surface of the article whilst substantially conforming to the surface of the article m:\speci\complete\1 12904soatjIl.doc

13. The method according to any one of claims 8 to 11, wherein the adhesive is selected from the group comprising heat sensitive, heat curing, silicone or pressure sensitive adhesive and heat melt adhesives.

14. The method according to any one of claims 1 to 13, wherein the article is supported upon an article support means, the article support means being at least partially air permeable, such that upon application of the at least a second pressure differential, the air present between the deformable web and the article is substantially removed through the article support means, and the sheet at least partially conforms to a surface of the article support means. The method according to claim 14, wherein the article support means has a geometry smaller than the geometry of the article such that the deformable web, upon application of the at least a second pressure differential, substantially conforms to the surface of the article so as to form a substantial undercut.

16. The method according to claim 14, wherein the article support means has a geometry larger than the geometry of the article such that the deformable web, upon application of the at least a second pressure differential, substantially conforms to the surface of the article so as to form a substantial overcut.

17. The method according to any one of claims 1 to 16, further comprising the step of at least partially covering the article with a reinforcement material prior to the article being relatively advanced into the aperture of the mechanical assist means.

18. The method according to any one of claims 1 to 17, further comprising the step of applying a design to the article prior to the article being relatively advanced into the aperture of the mechanical assist means.

19. The method according to claim 18, wherein the design is selected from the group comprising decorative film, silk screening and holograms. m:\speci\complete\1 12904soatjI.doc The method according to any one of claims 1 to 19, wherein the deformable web includes an integral design.

21. The method according to claim 1 to 20, further comprising the step of heating the deformable web prior to applying the at least a first pressure differential.

22. The method according to claim 21, further comprising the step of substantially cooling the deformable web after the deformable web has been substantially conformed to the surface of the article.

23. The method according to any one of claims 1 to 22, further comprising the step of reversing the article upon completion of step (iii) and repeating steps (ii) and (iii) such that the article is substantially encapsulated by the deformable web.

24. The method according to any one of claims 1 to 23, further comprising the step of applying at least a third pressure differential across the deformable web after the deformable web has substantially conformed to the surface of the article, such that the sheathed article is forced from the article support means. The method according to any one of claims 1 to 24, further comprising the step of removal of portion of deformable web which does not substantially conform to the surface of the article after completion of step (iii).

26. The method according to claim 25, wherein the step of removal is performed using mechanical trimming means.

27. The method according to claim 25, wherein the step of removal is performed using a laser cutting means.

28. The method according to claim 25, wherein the step of removal is performed using a fluid cutting means. m:\speccomplete\l 12904soatjl. doc

29. The method according to any one of claims 25 to 28, wherein the step of removal is automatically controlled. The method according to any one of claims 1 to 29, wherein at least one of the steps of the method is controlled automatically by a control means.

31. The method according to claim 30, wherein the control means is a Programmable Logic Controller, a computer or a microprocessor.

32. The method according to any one of claims 1 to 31, wherein the article is formed from a material selected from the group comprising metal, plastics, organic material and rigid gel.

33. The method according to any one of claims 1 to 31, wherein the article is of the form of an inflatable bladder.

34. The method according to any one of claims 1 to 31, wherein the article is selected from a group comprising surfboards, sailboards, boats, canoes, kayaks, life buoys, fishing net floats, other watercraft, water-safety devices, pontoons, buoyant devices or structures for maritime applications and skis; thermal insulation structures such as cool-rooms, saunas, flasks and insulated food and beverage carriers, devices for sound insulation such as panels, doors and roof sections; shock absorption, collision impact, impact resistant and resilient structures such as automobile bumper-bars, mattresses, cushioning devices, body boards, motor sport safety equipment and automobile parts. A device for sheathing an article with a deformable web, the device comprising: mechanical assist means having at least one aperture relatively positionable adjacent to a first side of the deformable web, the at least one aperture having a geometry so as to admit the article therein; means for providing a relatively greater pressure at a second side of the deformable web, such that a portion of the deformable web is expanded into the at least one aperture in a form of a bubble; m:\speci\complete\ 112904soatjLdoc means for relatively advancing the article within the at least one aperture of the mechanical assist means such that the article is located at least partially within the at least one aperture and the bubble; means for providing a relatively lower pressure at the first side of the deformable web such that air present between the second side of the deformable web and the article is substantially removed and the second side of the deformable web substantially conforms to the surface of the article; wherein the amount of deformable web which is expanded into the at least one aperture is regulated by geometry of the at least one aperture.

36. The device according to claim 35, wherein the deformable web is selected from a group comprising malleable metals, fluoropolymers, reinforced plastics, thermoplastics, thermoset plastics, resin wetted out reinforced cloths, thermoplastic elastomers, timber veneers, polymeric foams, woven cloths.

37. The device according to claim 35 or 36, wherein the aperture has a circumference and geometry greater than that of the greatest geometrical shape of the article, the aperture regulating the geometry of the bubble and the amount of deformable web which extends into the aperture.

38. The device according to any one of claims 35 to 37, wherein the means for providing a relatively greater pressure at the second side of the deformable web is the movement means for relatively advancing the article within the at least one aperture of the mechanical assist means causing an increase in air pressure.

39. The device according to any one of claims 35 to 37, wherein the means for providing a relatively greater pressure at the second side of the deformable web is a means for providing heated air at the second side of the deformable web. The device according to any one of claims 35 to 37, wherein the means for providing a relatively greater pressure at the second side of the deformable web is a vacuum means for applying at least partial vacuum at the first side of the deformable web. mrn:\specRcomplete\112904soatJl.doc

41. The device according to any one of claims 35 to 40, wherein the means for providing a relatively lower pressure at the second side of the deformable web is a vacuum mean for applying at least partial vacuum at the first side of the deformable web.

42. The device according to any one of claims 35 to 41, further comprising a device for applying pressure to the first side of the deformable web in a manner such that the second side of the sheet contacts the article and air present between the second side of the sheet and the article is progressively removed as the second side of the sheet is progressively contacted with the article.

43. The device according to claim 42 further comprising a flexible membrane for applying pressure to the first side of the deformable web.

44. The device according to claim 42 further comprising a means for providing air pressure to deformable web. The device according to claim 42 further comprising a substantially rigid member for applying pressure to the first side of the deformable web.

46. The device according to any one of claims 35 to 45, further comprising an article support means, the article support means being at least partially air permeable, such that upon application of the at least a second pressure differential, the air present between the sheet and the article is substantially removed through the article support means as the deformable web at least partially conforms to the surface of the article support means.

47. The device according to claim 46, wherein the article support means provides support for the article such that upon application of the relatively lower pressure at the first side of the deformable web, the article is not substantially deformed.

48. The device according to claim 46 or 47, wherein the wherein the article support means has a geometry smaller than the geometry of the article such that the deformable web, upon application of the at least a second pressure m:\spec\complete\112904soatjl.doc differential, substantially conforms to the surface of the article so as to form a substantial undercut.

49. The device according to claim 46 or 47, wherein the article support means has a geometry larger than the geometry of the article such that the deformable web, upon application of the at least a second pressure differential, substantially conforms to the surface of the article so as to form a substantial overcut.

50. The device according to any one of claims 46 to 49, wherein there is provided fluid communication between the article and the article support means such that upon application of pressure at the second side of the deformable web, the article and deformable web are forced from the device.

51. The device according to any one of claims 35 to 50, further comprising a means for heating the deformable web.

52. The device according to claim 51, further comprising a cooling means for substantially cooling the deformable web after the deformable web has substantially conformed to the surface of the article.

53. The device according to any one of claims 35 to 52, wherein the device is at least partially automatically controlled by a control means.

54. The device according to claim 53, wherein the control means is a Programmable Logic Controller, a computer or a microprocessor. The device according to any one of claims 35 to 54, further comprising a means for automatically loading the deformable web in the device.

56. The device according to any one of claims 35 to 55 wherein the article is formed from a material selected from the group comprising metal, plastics, organic material and rigid gel.

57. The device according to any one of claims 35 to 56, wherein the article is of the form of an inflatable bladder. m:\speci\complete\112904soatjil.doc

58. The device according to any one of claims 35 to 55, wherein the article is selected from a group comprising surfboards, sailboards, boats, canoes, kayaks, life buoys, fishing net floats, other watercraft, water-safety devices, pontoons, buoyant devices or structures for maritime applications and skis; thermal insulation structures such as cool-rooms, saunas, flasks and insulated food and beverage carriers, devices for sound insulation such as panels, doors and roof sections; shock absorption, collision impact, impact resistant and resilient structures such as automobile bumper-bars, mattresses, cushioning devices, body boards, motor sport safety equipment and automobile parts.

59. A sheathed article when made according to the steps of: applying at least a first differential pressure to a deformable web in a manner such that a portion of the deformable is caused to extend through at least one aperture located adjacent a first side of the sheet to form an extended, bubble like portion having a substantially constant wall thickness, the aperture having a geometry so as to admit an article therein; (ii) relatively advancing the article toward a second side of the deformable web and into the bubble like portion such that the article is located at least partially within the bubble like portion; and (iii) applying at least a second pressure differential across the deformable web, such that air present between the second side of the deformable web and the article is substantially removed and the second side of the deformable web substantially conforms to the surface of the article; wherein the amount of deformable web which is caused to extend through the at least one aperture is regulated by the geometry of the at least one aperture. The article according to claim 59, wherein the deformable web is selected from a group comprising malleable metals, fluoropolymers, reinforced plastics, thermoplastics, thermoset plastics, resin wetted out reinforced cloths, thermoplastic elastomers, timber veneers, polymeric foams, woven cloths.

61. The article according to claim 59 or 60, wherein the deformable web is heated prior to applying the at least a first pressure differential. m:\speci\complete\112904soatjI.doc 42

62. The article according to any one of claims 59 to 61, wherein the article is formed from an expanded polymeric material.

63. The article according to claim 62, wherein the expanded polymeric material is selected from the group comprising polystyrene, polyethylene polypropylene and polyurethane.

64. The article according to any one of claims 59 to 63, wherein the article further comprises a reinforcement means. The article according to claim 64, wherein the reinforcement means is a fibre mesh or mat.

66. The article according to any one of claims 59 to 63, wherein the reinforcement means is at least one at least partially internal reinforcement member.

67. The article according to any one of claims 59 to 66, wherein the reinforcement means is prestressed.

68. The article according to any one of claims 59 to 67, wherein the article is selected from a group comprising surfboards, sailboards, boats, canoes, kayaks, life buoys, fishing net floats, other watercraft, water-safety devices, pontoons, buoyant devices or structures for maritime applications and skis; thermal insulation structures such as cool-rooms, saunas, flasks and insulated food and beverage carriers, devices for sound insulation such as panels, doors and roof sections; shock absorption, collision impact, impact resistant and resilient structures such as automobile bumper-bars, mattresses, cushioning devices, body boards, motor sport safety equipment and automobile parts.

69. The method according to any one of claims 1 to 34, wherein the deformable web is selected from the group comprising polystyrene, polyethylene polypropylene, acrylonitrile butadiene styrene, styreneacrylonitrile, high impact polystyrene, general purpose polystyrene, polyurethane and polytetrafluoroethylene. m:\specicomplete\112904soatjI.doc The device according to any one of claims 35 to 58, wherein the deformable web is selected from the group comprising polystyrene, polyethylene polypropylene, acrylonitrile butadiene styrene, styreneacrylonitrile, high impact polystyrene, general purpose polystyrene, polyurethane and polytetrafluoroethylene.

71. A method for sheathing an article with a deformable web, substantially as described with reference to the accompanying figures.

72. A device for sheathing an article with a deformable web, substantially as described with reference to the accompanying figures.

73. A sheathed article, substantially as described with reference to the accompanying figures. Dated this seventeenth day of March 2003 Manufacturing Evolutions (NZ) Limited Patent Attorneys for the Applicant: F B RICE CO m:\speci\complete\1l 2904soatjl.doc