WO2009034463A1

WO2009034463A1 - Footgear

Info

Publication number: WO2009034463A1
Application number: PCT/IB2008/002384
Authority: WO
Inventors: Roberto Monti
Original assignee: Gh Srl
Priority date: 2007-09-13
Filing date: 2008-09-12
Publication date: 2009-03-19
Also published as: ITMI20071760A1

Abstract

A footgear (10) is described of the type comprising a sole (12), a heel (14) and at least one upper element (16). At least part of the group consisting of the sole (12) and the heel (14) is made with a reinforced polymer material.

Description

FOOTGESLR

DESCRIPTION

The present invention refers to footgear or shoes in general, and more precisely to an innovative material applicable to at least part of the components forming a shoe .

In the manufacturing of shoes known at the state of the art, especially those intended for a particularly high-end market, predominantly natural materials are used, such as leather and rubber, or synthetic materials having similar aspect to the natural materials. Nevertheless, even if manufactured with production processes which ensure high product quality, the shoes of known type do not lack some annoying drawbacks .

The use of the aforesaid materials, especially in manufacturing those components of the shoe that are more stressed and subject to wear, such as the sole and the heel, gives rise to a relative fragility of the shoe itself. In daily use, breaks of the heel or part thereof often occur, especially in those shoes intended for the female market in which the heel is slender and/or particularly high.

In addition, it is normally necessary to make the sole and heel in the form of two separate components, which must then be skilfully united, usually by means of gluing, during the subsequent working steps of the shoe.

The object of the present invention is therefore that of overcoming the abovementioned drawbacks of the prior art by making a shoe particularly resistant to wear and accidental breakage that can occur during its use .

Another object of the invention is that of providing for a shoe in which it is possible to make the heel and the sole in a single piece, with clear aesthetic (continuity of the curves without cuts) , strength (without subsequent gluing between sole and heel) and manufacturing simplicity advantages.

A further object of the invention is that of making a considerably lighter shoe, while maintaining the same outer aspect characteristics and comfort, with respect to analogous shoes of known type.

These objects according to the present invention are achieved by making an improved shoe as set forth in claim 1.

Further aspects of the invention are highlighted by the subsequent claims.

The characteristics and advantages of an improved shoe according to the present invention will be clearer from the following exemplifying and non-limiting description, referred to the attached schematic drawings in which:

Figure 1 is a perspective view of an embodiment of a shoe according to the present invention;

Figure 2 is an exploded view of part of the elements composing the shoe of figure 1;

Figure 3 is a perspective view of a first embodiment of an element which composes a shoe according to the present invention;

Figure 4 is a perspective view of a second embodiment of an element which composes a shoe according to the present invention;

Figure 5 is a perspective view of a third embodiment which composes a shoe according to the present invention;

Figures 6 - 8 are perspective views of other shoe embodiments according to the present invention. With reference to the figures, a shoe is shown overall with the reference number 10, represented as an exemplifying but non-limiting example of a women' s sandal, of a clog, of a classic men's shoe and of a women's shoe with wedge.

The shoe 10 comprises a sole 12 and a heel 14, both prearranged for the ground contact by means or not by means of interposed elements, as well as an upper element 16. With the term "upper" it is intended a layer, generically leather, imitation leather or other material, suitable for forming the surface or surfaces which cover the foot. In the particular embodiment illustrated in figures 1 - 6, referred to a women's sandal and to a clog, the upper element 16 is defined by one or more straps constrained to the sole 12 in order to keep the shoe 10 on the user's foot. In the particular embodiment illustrated in figure 7, referred to a classic men's shoe, the upper element 16 is instead more articulated and is intended to cover the entire foot.

The shoe 10 can therefore be provided with an insole 18, interposed between the sole 12 and the upper element 16, and one or more inserts of soft material 20 placed below the insole 18 itself, at the user's heel, in order to make the use of the shoe 10 itself more comfortable.

Advantageously, according to the present invention, at least part of the group consisting of the sole 12 and the heel 14 of the shoe 10 is made with a carbon fibre - based material. Other long fibre composite materials adapted for achieving the invention are described below.

Advantageously, at least part of the heel 14 is integrally made, in a single piece, with at least part of the sole 12.

Preferably, as shown in figure 3, the sole 12 and the heel 14 are integrally made, in a single piece, of carbon fibre obtained starting from a single mould. Alternatively, the groups composed of the sole 12 and the heel 14 can be made in the form of two or more separate components.

As is shown in the embodiment of figure 4, the sole 12 and the heel 14 can in fact be made of ^' two half-shells 22 and 24 that are substantially symmetrical with respect to a vertical plane. The two half-shells 22 and 24 will then be joined, by means of gluing or with analogous processes, during the working steps of the shoe 10.

As shown, instead, in the embodiment of figure 5, the sole 12 and the heel 14 can also be made in the form of a first component 26, which comprises the heel 14 and the lower portion of the sole 12, and a second component 28, which forms the upper part of the sole 12. Also in this case, the two components 26 and 28 must be joined, by means of gluing or with analogous processes, along a plane substantially parallel to the extension plane of the sole 12.

The carbon fibre - based material used in making the shoe 10 can be obtained, for example, according to the process called "pre-preg", in which a carbon fibre fabric is deposited in a mould after having been previously impregnated with epoxy resins.

The resin is found in a metastable state, so that at room temperature the catalyst process is slowed and the resin itself appears nearly solid and sticky. The latter property facilitates the application of the fibre layers, which are arranged according to a predefined design and thus remain in position on the resin substrate. The product thus obtained is heated in the oven to a temperature of 80°C÷120°C such that, during the heating, the resin is fluidified, facilitating the exit of air bubbles, and subsequently hardens due to the catalyst process.

In the manufacturing process of the shoe 10 according to the invention, the carbon fibre fabric pre-impregnated with epoxy resin is applied to the moulds, of metal or plastic material with high heat resistance, suitable for forming the shoe 10 itself. Subsequently, the pre-impregnated fabric is baked at a predefined temperature in suitable ovens in order to extract the completed shoe shape in the end.

Given the relatively low temperature at which the pre-impregnated fabric must be baked, even small ovens can be conveniently used of battery type, making the manufacturing process of the sole 12 and the heel 14 of the shoe 10 according to the present invention quite simple and easy.

Alternatively to that reported above, it is possible to use other types of semifinished products in the production of the sole 12 and heel 14 of the shoe 10 according to the invention.

The use of fabrics made of carbon fibre pre- impregnated with epoxy resin was described above.

As already mentioned, in place of the carbon fibres, in order to meet specific needs, other fibres can be used such as glass fibres, polyaramid fibres, or fibres of other polymers such as UHMW (Ultra High Molecular Weight) polyethylene, polyvinyl alcohol, polyester or liquid crystal polymers.

Each fibre type can be used on its own or in combination with others. Hybrid fabrics are available, for example, in which fibre bands of one type (for example carbon) are woven with fibre bands of another type (for example polyaramid fibres) . It is also possible that different fibre types can be superimposed in an alternating manner in the different reinforcement layers.

In addition, in place of the fabrics, it is possible to employ unidirectional bands or sheets, composed of fibres arranged parallel to each other in a single direction. On the other hand, the fabrics comprise interlacing fibres in the two weft and warp directions .

In addition, in place of the pre-impregnated fibres, it is possible to use dry fibres, to which the resin is then added in the fluid state before the oven baking step.

Finally, in place of the epoxy resins, it is possible, in order to meet specific needs, to use different resin types, of thermosetting or thermoplastic type.

Regarding the fibres, a particularly advantageous characteristic is that they have an average length on the order of the size characteristic of the achieved piece, for example of the sole 12 and of the heel 14 of the shoe 10. In other words, the reinforcement fibres in the shoe 10 according to the invention have several centimetres length and predefined direction at the time of the arrangement of each of the fibre layers. Such reinforcement type, advantageously employed in the present invention, is called "long fibre".

In other reinforcement types, not of great interest for the present invention, the fibres are present in fragments (or "whiskers") with length on the order of a millimetre, and are dispersed in the resin with previously undefined directions. Such reinforcement type is called ^λλ short fibre".

The sole 12 and/or heel 14 thus obtained can be provided with grooves and/or open portions (not shown) for facilitating the application, for example by means of gluing, of the insole 18, of the upper element 16 or of suitable straps in the subsequent finishing steps of the shoe 10. Possibly, in order to improve the elasticity and the easy of use of the shoe 10, the front portion 30 of the sole 12 can be made of leather, or with other analogous flexible fabrics or materials, rather than of carbon fibre.

The sole 12 and the heel 14 can thus be painted in the desired colours, given the extreme ease with which it is possible to apply paints or other coating types on the carbon fibre material. Finally, further finishing details or accessories can be applied, in a per se known manner, such as for example ground contact elements 32 and 34 respectively placed below the heel 14 and the front part of the sole 12, made for example in rubber or in aramid fabric and having anti-slip function, or ornamental elements (not shown) on the straps 16.

Preferably, in the shoe 10 according to the invention, the heel 14 and the sole 12 are connected, in the zone where they are integrated with each other, by means of a suitable fillet radius r. Such solution prevents the concentrations of the stress which are typically generated near the notches and/or sharp edge section changes.

It has thus been seen that a shoe like that according to the present invention attains the above highlighted objects since, due to the use of carbon fibres, it is particular strong and light.

Indeed, the production of the sole and heel integrated with each other avoids all the problems seen with reference to the prior art. In particular, the known joint between heel and sole, usually obtained by means of gluing, conventionally forms a weak point of the shoe.

In the shoe type represented in figure 1, thus having an elongated and slender heel, the joint between heel and sole is particularly delicate and is often subject to breakage. The structure of the shoe is in fact shaped for sustaining a load (typically the weight of the user) substantially aligned with the heel axis. In such load condition, the gluing and the heel are compression loaded and have a particularly high strength. The most difficult load conditions are those which occur, for example during walking, when the weight of the user is not aligned with the axis of the heel. In these load conditions, a bending moment is generated which has its maximum at the joint between the heel and the sole. Such moment is higher the higher the heel and the more the load is misaligned from the axis of the heel itself. These load conditions, even if temporary, often bring the gluing beyond the break point, with consequent separation of the heel from the shoe.

In different shoe types, for example a men's shoe like that represented in figure 7, the joint between heel and sole is subjected to less critical loads with respect to that described above. The heel is in fact decidedly more stubby than that of the shoe of figure 1. It is thus improbable that significant moments are generated in such structure due to a non-aligned load. On the other hand, however, men's shoes conventionally have a decidedly longer operating life than the women's shoes. For such reason, the gluing between the heel and sole is subject to aging and degradation due to weathering agents and in particular moisture, UV rays, surface abrasion and possibly chemical agents. The consequent weakening can lead to the yielding of the gluing, for example in shear stress conditions between heel and sole.

Analogous considerations can be carried out for a shoe of the type represented in figure 6. In such shoe type, however, the greatest advantage deriving from the use of the composite material according to the invention is connected with the lightness of the structure. The structure of a clog of conventional type is in fact a suitably shaped piece of solid wood. The structure of a clog according to the present invention having analogous shape and size results decidedly lighter.

Analogous advantages can also be obtained with the shoe type represented in figure 8. Such shoe in fact comprises a support of the sole or wedge 36. With a conventional embodiment of the shoe, such configuration involves an additional solid structure that considerably affects the overall weight of the shoe. In a shoe 10 according to the invention, on the other hand, the wedge 36 of composite material is decidedly lighter.

Moreover, due to the relative simplicity with which it is possible to finish the semifinished products made of carbon fibres, the step of applying the finishing on the shoe is simple and quick, and can be carried out in most shoe factories without requiring the use of particular technical knowledge and sophisticated machinery.

The shoe of the present invention thus conceived is susceptible to numerous modifications and variants, all part of the same inventive concept; moreover, all details can be substituted with technically equivalent elements. In practice, the shapes and sizes can be of any type according to the technical needs .

The protective scope of the invention is therefore defined by the attached claims.

Claims

1. A shoe (10) of the type comprising a sole (12), a heel (14) and at least one upper element (16), characterised in that at least part of the group constituted by said sole (12) and said heel (14) is made with a long fibre composite material.

2. A shoe (10) according to claim 1, characterised in that said long fibre composite material is a carbon fibre - based material.

3. A shoe (10) according to claim 1 or 2, characterised in that at least part of said heel (14) is integrally made, in a single piece, with at least part of said sole (12) .

4. A shoe (10) according to any one of the preceding claims, characterised in that said sole (12) and said heel (14) are integrally made in a single piece obtained starting from a single mould.

5. A shoe (10) according to any one of the preceding claims, characterised in that said sole (12) and said heel (14) are made of two half-shells (22, 24) that are substantially symmetrical with respect to a vertical plane, said two half-shells (22, 24) being joinable by means of gluing.

6. A shoe (10) according to any one of the preceding claims, characterised in that said sole (12) and said heel (14) are made in the form of a first component

(26) , comprising said heel (14) and the lower portion of said sole (12), and a second component (28), which forms the upper part of said sole (12), said two components (26, 28) being joinable by means of gluing along a plane substantially parallel to the extension plane of said sole (12) .

7. A shoe (10) according to any one of the preceding claims, characterised in that said sole (12) and/or said heel (14) are provided with grooves and/or open portions for facilitating the application of said upper element (16) .

8. A shoe (10) according to any one of the preceding claims, characterised in that the front portion (30) of said sole (12) is made of a flexible material in order to improve the elasticity and ease of use of said shoe

(10) .

9. A shoe (10) according to any one of the preceding claims wherein said composite material comprises reinforcement fibres embedded in a polymer resin.

10. A shoe (10) according to claim 9, wherein the reinforcement fibres are made with a material selected from the group comprising: carbon, glass, polyaramid, UHMW polyethylene, polyvinyl alcohol, polyester and liquid crystal polymers.

11. A shoe (10) according to claim 9, wherein said resin is of thermosetting type or thermoplastic type.

12. A shoe (10) according to any one of the preceding claims, moreover comprising a fillet radius (r) in the zone where part of the heel (14) is integrated with part of the sole (12) .