FR2815231A1 - Insole has cut-out section under ball of foot which contains pad filled with a visco-elastic material - Google Patents

Abstract

The insole has a cut-out section (2) under the ball of the foot. This contains a pad (16) filled with a visco-elastic material (15) . There is a small gap between the edges of the material and the edges of the cut-out.

Description

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MULTIPURPOSE FINE SOLE
The present invention relates to a thin sole comprising a thin support cut out in the form of a sole and intended to be inserted into a shoe.

 The human foot is a complex system in which the different parts cooperate in order to allow the various movements of locomotion specific to the human being, such as walking, running, landing or jumping.

 However, it is often necessary to use corrective or compensating insoles in different circumstances such as the aging of muscle, ligament or bone functions, the protection of these functions in case of intensive use or even orthopedic correction when pain must be relieved. Note that such pains can be localized at the level of the foot, but can also spread to other parts of the body, for example, the ankle, the knee or the spine.

 For this purpose, materials have been developed for a very long time to allow an amplification of the natural cushioning conferred by the human plantar pad.

Various additional shock absorbing soles, intended to be inserted into shoes, have thus been marketed. The cushioning property of these soles is presented as an important and advantageous characteristic which is supposed to limit the stress of the spine. Unfortunately, as many shoes are already very cushioning, the use of such materials up to the forefoot leads the user to have to compensate for this.

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 cushioning during the propulsion phase of the foot, which can lead to the appearance of tendonitis.

 Another disadvantage of conventional additional soles is that they must replace the original soles because of their size, since they are generally mounted with foam supports which have significant thicknesses.

 On the other hand, viscoelastic materials called load distributors have also been developed to optimize the load distribution on the forefoot.

Let us cite in particular the silicone gels described in patent FR-2 712 487, which have the advantage of reproducing the mechanical properties of the human plantar pad in compression and in torsion. Silicone gels having such properties are also sold by the applicant under the names EPITHELIUM 26, EPITHELIUM 27 or EPITHELIUM 27+. They give remarkable results in terms of comfort.

 However, these materials cannot be used on the entire foot. Applied for example on the heel area, they could cause posture instabilities corrected reflexively by cramping of the toes generating pain, or by a solicitation of the leg muscles also causing pain or cramps.

 Thus, these materials are generally incorporated in the form of pads in socks or low protectors allowing their application on a specific area of the foot. However, such socks or stockings have the disadvantage of being of average effectiveness for maintaining a viscoelastic material in a precise area of the foot without risk of slipping of the material following movements of the foot in the shoe. In addition, the introduction under the foot of a load-distributing pad has the disadvantage of unbalancing the posture of the user and can cause undesirable side effects.

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Thus, an objective of the present invention is to provide a sole intended to be inserted into a shoe, which allows the firm hold on a foot area of a viscoelastic load-distributing material.

 Another objective of the present invention is to provide a sole of the aforementioned type which is thin and compact, and which can be introduced into a shoe without it being necessary to remove the initial sole present in the shoe.

 These objectives are achieved by providing a thin sole comprising a thin support cut out in the shape of a sole and intended to be inserted in a shoe, characterized in that the support has an orifice cut out in a front part of the corresponding support that is substantially to a support area of the foot, and in that a pad containing a viscoelastic load-distributing material is arranged in the orifice, the periphery of the pad being integral with the support.

 Advantageously, the edges of the viscoelastic material are arranged at a determined distance from the edges of the orifice made in the support, so that the viscoelastic material does not overflow or overflows little on the support during the crushing of the pad by the foot. .

 According to one embodiment, the viscoelastic material is sandwiched between two pieces of fabric or other equivalent material, and is held laterally by a zone for fixing the two pieces of fabric produced by sewing, gluing or welding.

 According to one embodiment, the lower face of the viscoelastic material is glued or fixed to the lower piece of fabric while the upper face of the viscoelastic material is not glued or fixed to the upper piece of fabric.

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According to one embodiment, the lower piece of fabric has the same shape as the support and constitutes with the support a double layer sole support.

 According to one embodiment, the viscoelastic material is a silicone gel having mechanical properties close to those of the human plantar pad.

 According to one embodiment, the periphery of the pad is fixed to the underside of the support by sewing, gluing or welding.

 According to one embodiment, the support is made of a microporous material having a good ability to absorb and desorb liquids.

 According to one embodiment, the heel area of the sole includes a shock absorber module fixed on the support.

 Preferably, the sum of the thickness of the damper module and the thickness of the support is substantially equal to the thickness of the bearing.

 Preferably, the pad is substantially thicker than the support.

 These objects, characteristics and advantages, as well as others of the present invention, will be explained in more detail in the following description of a sole according to the invention and of a method of manufacturing such a sole, given without limitation. in relation to the attached figures among which: - Figure 1 shows a sole according to the invention, - Figures 2A, 2B, 3A, 3B, 4A and 4B illustrate a method of manufacturing a sole according to the invention.

 FIG. 1 represents a sole 10 according to the invention, comprising a basic material, or support 1, cut to the shape of a shoe into which the sole is intended to be inserted.

 The support 1 constitutes a means of connection vis-à-vis other elements of the invention described below and is preferably as thin as possible, for example

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 with a thickness between 0.6 and 1.5 mm. It is preferably made of a microporous material, in particular a microporous polyethylene doped with silica of the type sold by the company AEROSHOES. Such a material is resistant, washable and contributes to obtaining a healthy sole by limiting the phenomenon of maceration due to perspiration, thanks to its ability to absorb and desorb liquids. In addition, such a material takes the form of the sole on which it rests so that it is not necessary to preform it according to the geometries of the shoes, which are always very different. It can also be treated against bacterial development.

 According to the invention, the front central part of the support 1 has an orifice 2 located in the region corresponding to the front support area of the foot. The orifice 2, of substantially circular or elliptical shape, receives a viscoelastic pad 16 whose periphery is fixed to the rear face of the support 1, for example by means of a seam 13 traversing the edges of the orifice 2. The pad 16 has a bulge oriented towards the foot, formed by a viscoelastic material 15. The material 15 is preferably a silicone gel having properties similar to that of the human plantar pad. It is, for example, a composition with two or three silicone oils of the type described in patent FR-2,712,487 or a product such as EPITHELIUM 26 sold by the applicant.

 The viscoelastic material 15, substantially flat, is of a thickness greater than that of the support 1, for example between 2 and 2.5 mm. It is covered by a piece of flexible and elastic fabric 11, for example polyamide elastane, and is held laterally in the plane of the sole by a seam 12 connecting the piece of fabric 11 to a piece of lower fabric (not shown in the figure 1).

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The edges of the bulge formed by the viscoelastic material 15, delimited by the seam 12, are arranged at a distance D from the edges of the orifice 2. This distance D, of the order of a few tenths of a millimeter, for example 0.5 mm, is chosen so that the viscoelastic material 15, the size of which increases laterally under the effect of the crushing, does not overlap or overlaps slightly on the support 1 when the foot is in abutment on the pad. A silicone gel in fact comprises a percentage of non-crosslinked silicone oil which is released (released) slowly by the material after its crosslinking. Thus, in the absence of the distance D, the viscoelastic material 15 would risk drying out and losing its viscoelastic properties by coming into contact with the microporous support 1, which has a good capacity for absorbing liquids, despite the presence elastane fabric 11 which covers it.

 In practice, the distance D is thus chosen so that the surface of the viscoelastic material 15 coming into contact with the microporous support 1 during a crushing of the pad is zero or sufficiently small to not cause it to dry out quickly and, more generally, to avoid mechanical interference.

 According to another aspect of the invention, optional but advantageous, the rear part or heel area of the support 1 comprises a module 5 made of a damping material. It is for example a rubber module, in particular a material sold under the name "CATANE" by the company CATY POLYMERES, having good damping properties. Preferably, the total thickness of the heel area, equal to the sum of the thickness of the module 5 and the thickness of the support 1, is substantially equal to that of the pad 16 in order to provide the foot with a substantially horizontal seat. and rebalance the user's posture. The module

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 5 is thus preferably of a thickness not exceeding 1 to 2 mm.

 Thus produced, the sole 10 according to the invention offers various advantages.

 On the one hand, the viscoelastic pad 16, placed at the front of the sole, is a load distributor which not only makes it possible to compensate for a leak in the plantar pad (disappearance of the pad following aging of the foot) but also makes it possible to eliminate low back pain and knee pain (tendonitis of the knee) for people with hallux or axial feet.

 On the other hand, the rear module 5 cooperates with the cushion 16 by ensuring a double function of rear cushioning and load distribution at the front, which is of real interest for people suffering from a weakening of the plantar pad. and who see their bone structure confronted with the consequences of age. This interest is also proven in the case of sportsmen practicing a sport which promotes the birth of tatalgia and metatarsalgia.

 Finally, due to its small thickness, the sole according to the invention 10 can be inserted into a shoe without it being necessary to remove the original sole.

 Yet another advantage of the invention is linked to the use of the microporous material as support 1, because it forms a kind of interface between the shoe and the foot which combines properties of comfort, sanitation and adaptability to the geometry of the shoe.

 A method of manufacturing a sole according to the invention will now be described in relation to FIGS. 2A, 2B, 3A, 3B, 4A and 4B.

 A microporous polyethylene sheet is firstly stabilized by washing at temperature (300C) to guarantee the maintenance of its dimensional characteristics. We preferably choose a sheet

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 with a thickness between 0.6 and 1.5 mm, although greater thicknesses can be envisaged.

As illustrated in FIG. 2A, the material is then cut according to the size of the sole that is to be obtained, to form the support 1 described above.

The orifice 2 is made in the front part of the support 1 simultaneously or after the cutting of the contour. The shape of the orifice 2 corresponds substantially to that of the load-distributing pad which will be incorporated therein, increased by the tolerance "D" described above.

 In FIG. 2B, a module 5 has been cut from a plate of material such as CATANIA, and has been fixed on the support 1. The shape of the module 5 corresponds to that of the rear part of the support 1. The module 5 is preferably cut slightly at an angle relative to its transverse axis, as is done for the heel of a shoe. The length of module 5 is such that it does not encroach on the arch of the foot. The module 5 is bonded to the support 1 by any appropriate means, the microporous structure of the support contributing to the effectiveness of this method of fixing.

 A pad 16 is then produced according to steps illustrated in FIGS. 3A and 3B.

 In the step of FIG. 3A, a viscoelastic gel module 15 of flat and substantially circular shape is bonded to a piece of fabric 10, for example made of polyamide elastane. In the step of FIG. 3B, a similar piece of fabric 11 is deposited on the viscoelastic module 15 and is sewn to the piece of fabric 10.

The seam 12 is made by following the contours of the module 15 which is thus enclosed in the fabric, its lower face being glued and its upper face remaining free.

 As illustrated in FIG. 4A, the pad 16 thus produced is then arranged inside the recess 2 formed in the support 1, the unglued part of the

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 viscoelastic module 15 being oriented on the side of the support 1 which receives the damper module 5. In other words, it is the side of the module 15 not bonded which will be in contact with the foot of the user, via fabric 11. Next, around the recess 2, a seam 13 is made which simultaneously secures the two pieces of fabric 10, 11 to the support 1.

 Of course, the sewing steps mentioned above can be replaced by gluing steps.

Heat sealing steps can also be envisaged if fabrics comprising thermoplastic fibers are used.

 As can be seen in FIG. 4B, which represents the rear face of the sole 10 according to the invention, the excess fabric 10, 11 at the rear of the sole is then cut so as to leave a collar around the pad 16 14 with a width of 1.5 to 3 mm.

 One can then deposit on the rear face of the sole 10 a layer of a washable non-slip material (not shown), in particular a layer of reusable glue (which can be peeled off and glued), which allows the sole to adhere to the bottom 'a shoe. The adhesive layer is protected by a removable protective film such as a polyethylene film.

 Thanks to this manufacturing process, the viscoelastic module 15 present in the pad 16 is correctly arranged with respect to the plantar zone targeted, since the recess in which it is installed is itself correctly arranged with respect to the end of the sole. The pad 16 fully fulfills its role as load distributor, since it is free between the shoe and the foot and can be compressed without being hindered by the sole, the thickness of which is less than that of the pad. Finally, the distance D provided between the edges of the viscoelastic module 15 and the edges of the recess 2 avoids the appearance of a stress on the pad 16

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 which could increase its hardness at the expense of the viscoelastic effect.

 Thus, according to the invention, a sole is produced which offers an optimal load distribution on the forefoot, on the one hand thanks to the intrinsic properties of the viscoelastic module 15, optimized by the choice of a material such as EPITHELIUM 26, and on the other hand thanks to the good arrangement of the module 15 relative to the connecting element (support 1), the shoe and the foot. On the other hand, the sole offers good rear cushioning to limit the effects of shocks caused by putting the foot on the ground, although the shock absorber module 5 can be removed or offered as an option depending on the users or the type of shoe targeted. . Finally, the sole according to the invention is very healthy thanks to the properties of the moisture-absorbing material used to produce the support 1, whether or not the latter is treated with antibacterial agents.

(the use of treated leather can also meet the requirements of the invention). It adapts naturally to the shape of the space between the foot and the sole of the shoe, is easy to maintain and can be fully machine washed without risk of alteration.

 It will be clear to those skilled in the art that the sole which has just been described is capable of various embodiments and improvements while remaining within the spirit of the present invention.

In particular, if we refer again to Figures 3A, 3B and 4A, we see that the piece of fabric 10 forming the base of the pad 16 can be provided in the same shape as the support 1 (and can also be constituted by a microporous material). In this case, during the step shown in FIG. 4A, the piece of fabric 10 is covered by the support 1 and is assembled to the latter over its entire surface, for example by gluing. A double layer support is obtained formed by the initial support 1 and the piece of fabric 10. In such an embodiment, the support 1 and the piece 10 can be cut out.

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 together at a final stage of the manufacturing process, for example by stamping. A collective manufacture of soles according to the invention, from large pieces of fabric, can then be envisaged.

Claims (11)

1. Thin sole (10) comprising a support (1) of small thickness cut in the form of a sole and intended to be inserted in a shoe, characterized in that the support (1) has an orifice (2) cut in a front part of the support corresponding substantially to a support area of the foot, and in that a pad (16) containing a viscoelastic material (15) is distributed in the orifice (2), the periphery of the pad (16) being integral with the support (1).  2. Sole according to claim 1, wherein the edges (12) of the viscoelastic material (15) are arranged at a determined distance (D) from the edges of the orifice (2) formed in the support (1), so that the viscoelastic material (15) does not overflow or overflows little on the support (1) during the crushing of the pad (16) by the foot.  3. Sole according to one of claims 1 and 2, wherein the viscoelastic material (15) is sandwiched between two pieces of fabric (10,11) or other equivalent material, and is held laterally by a fixing zone ( 12) of the two pieces of fabric (10,11) produced by sewing, gluing or welding.  4. Sole according to claim 3, in which the lower face of the viscoelastic material (15) is glued or fixed to the lower piece of fabric (10) while the upper face of the viscoelastic material (15) is not glued or fixed to the upper piece of fabric (11).  5. Sole according to one of claims 3 and 4, wherein the lower piece of fabric (10) is <Desc / Clms Page number 13>  same shape as said support (1) and constitutes with said support (1) a double layer sole support.  6. Sole according to one of claims 1 to 5, wherein the viscoelastic material (15) is a silicone gel having mechanical properties close to those of the human plantar pad.  7. Sole according to one of claims 1 to 6, wherein the periphery of the pad (16) is fixed to the underside of the support (1) by sewing (13), gluing or welding.  8. Sole according to one of claims 1 to 7, wherein the support (1) is made of a microporous material having a good ability to absorb and desorb liquids.  9. Sole according to one of claims 1 to 8, comprising in its heel area a shock absorber module (5) fixed on the support (1).  10. Sole according to claim 9, wherein the sum of the thickness of the damping module (5) and the thickness of the support (1) is substantially equal to the thickness of the pad (16).  11. Sole according to one of claims 1 to 10, in which the pad (16) is substantially thicker than the support (1).