FR2628300A1 - Moulded PVC shoe sole with insert of softer lighter material EVA - for reduced wt. and enhanced comfort - Google Patents

Abstract

Composite shoe sole has a moulded base with a peripheral wall to enclose a prefabricated insert made of a more flexible and lighter material. The insert is mounted while the sole is still hot so that the insert is gripped by the peripheral walls as the sole cools. Pref. the sole is of PVC, the insert of EVA (ethylene-vinyl acetate copolymer). The insert should be thick enough to prevent the wearer from sensing internal ribs in the sole. The insert is basically solid, but may have holes or slits to reduce its wt. and/or increase its flexibility. The anchorage of the insert may be enhanced by welding or adhesives. Pref. the upper has ancillary flaps to provide an internal cover for the sole. USE - Esp. for footwear having relatively thick soles, for comfort or style, esp. mocassins to reduce the wt. of rigidity thereof.

Description

"Method of manufacturing an article of footwear"
The present invention relates to a method of manufacturing an article of footwear and in particular an article of footwear of the moccasin type.

 Sports shoes with thick soles are currently very popular with consumers, and manufacturers are therefore increasingly directing their production towards this type of article.

 In addition to considerations purely related to aesthetics, it is however necessary, to satisfy consumers, to offer them shoes that are as comfortable as possible ~ or, if lton increases the thickness of the sole of a footwear item, we Of course, it increases its weight in a way that can create discomfort for users, and consequently limit the audience of such articles with the public.

 The object of the invention is to remedy this drawback by proposing a method allowing the manufacture of an article of footwear having an outsole which is relatively thick on the outside, but of a weight which is greatly reduced compared to articles currently on the market.

 This process is characterized in that an injection mold, by a known operation itself, a relatively thick sole made of a thermoplastic synthetic material, in particular of polyvinyl chloride having a recess in its central part, an insert is manufactured in parallel. flexible and light synthetic material of dimensions corresponding to those of the recess, then, immediately after the molding of the sole, when the latter is still hot, the insert is placed in place in the recess so that it , coming to level is perfectly maintained thanks to the shrinkage occurring on cooling.

 According to the invention, the dimensions of the recess and the insert obviously correspond to each size.

 Particularly satisfactory results have been obtained from the point of view of user comfort by manufacturing the insert from a particularly flexible synthetic material sold under the name EVA (registered trademark); in addition to its aforementioned flexibility qualities, this material also has heat insulating properties which are also such as to improve the comfort of the user. Of course, the choice of EVA (registered trademark) should in no way be considered as limiting, and the material constituting the insert could be other without departing from the scope of the invention.

 According to another characteristic of the invention, the recess comprises a substantially planar bottom wall surrounded by side walls of constant height substantially perpendicular to the bottom wall.

 This is a particularly important characteristic of the invention, given that it allows the installation of an insert which is also essentially planar, and which can therefore be cut from a strip or plates of synthetic material of constant thickness corresponding to the height of the side walls of the recess, in particular by means of a cookie cutter.

 The manufacture of footwear is thus significantly simplified and its cost price reduced at the same time.

 According to another characteristic of the invention, during molding, the bottom wall of the recess is provided with lightening cells separated by cross-pieces.

 This characteristic, by reducing the volume of the thermoplastic material constituting the sole, allows significant reduction of the article; it is of course necessary for the comfort of the user that the latter cannot feel the lightening braces when he is wearing the shoe, and that, as a result, the flexible insert, in particular made of EVA (registered trademark) have sufficient thickness.

 According to another characteristic of the invention, the insert is provided with transverse slots and / or perforations in order to increase its flexibility and consequently improve the comfort of the user.

 Particularly satisfactory results are obtained from the point of view of the flexibility of the article obtained by providing slots at the level of the pad and rows of parallel perforations at the level of the casing zt of the camber.

 Without this being a limiting characteristic of the invention, the sole assembly formed by the sole and the insert obtained by the implementation of the above-mentioned process is often used in the context of the manufacture of articles shoes of the moccasin type which are particularly comfortable for.

the consumer because the sole of the foot thereof is in contact with the same material (generally leather) as the upper of the shoe.

 According to another characteristic of the process according to the invention, more particularly intended for the manufacture of such moccasins, it is fixed in particular by gluing, on the sole assembly defined by the sole and the insert, at the level of the forefoot. , a moccasin-type half-first body made with a rod, notably of leather, which is mounted on the periphery of the sole assembly.

 According to another characteristic of the invention, a semi-first is glued in particular from a synthetic material such as polyvinyl chloride at the casing and, where appropriate, the camber of the article.

 As already indicated, this process makes it possible to obtain particularly comfortable moccasin-type articles, because the forefoot of the user is in contact with the leather which is itself in contact with the layer of EVA (registered trademark) which isolates it from the hardness of the cross-pieces of the lightening cells of the sole.

 The invention obviously also relates to an article of footwear and in particular to an article of footwear of the moccasin type which is obtained by implementing the above-mentioned method; such an article is characterized in that it comprises a sole formed by an externally relatively thick sole and comprising in its central part a recess occupied by an insert made of a flexible and light material, in particular EVA (registered trademark) coming at level.

 The density and flexibility properties of EVA (registered trademark) allow the production of footwear having soles with a thick external appearance without increasing their weight compared to articles having thinner soles and providing more comfort.

The characteristics of the process as well as of the footwear which are the subject of the invention will be described in more detail with reference to the accompanying drawings in which
FIG. 1 shows the sole of the footwear,
- Figure 2 shows the insert of this article,
- Figure 3 is a longitudinal section of a moccasin blank during manufacture.

 The first step in the process for manufacturing an article of footwear consists in manufacturing a sole assembly consisting of a sole 1 shown in FIG. 1 and an insert 2 shown in FIG. 2. These two elements 1 and 2 are produced in parallel.

 According to FIG. 1, the sole 1 whose thickness a is relatively large is injection molded from a thermoplastic synthetic material and in particular from polyvinyl chloride; it has in its central part a recess 3 comprising a bottom wall 4 which is essentially planar surrounded by side walls 5 of constant height b which are essentially perpendicular to the bottom wall 4. The recess 3 in fact occupies most of the face upper of the sole 1, with the exception of a border 6, and has dimensions depending each time on the size of the article.

 The lower wall 4 of the recess 3 is provided, during molding, with lightening cells 7 separated by crosspieces 8. The particular geometry of the crosspieces and the cells shown in FIG. 1, differing at the level of the pad and at the casing and the camber, should of course not be considered as limiting the invention.

 According to Figures 2 and 3, the recess 3 is intended to receive an insert 2 of corresponding dimensions in a material that is both flexible, light and dense, in particular EVA (registered trademark); the thickness b of the insert 2 corresponds exactly to the height of the side walls 5 of the recess 3 so that it can come to level; it is also essential that the dimension b is sufficiently large, and therefore the insert 2 sufficiently thick so that the user cannot feel the braces 8 when carrying the article, thanks to the flexibility of the EVA (brand filed).

 Thanks to its constant thickness b, the insert 2 shown in FIG. 2 can be cut, not shown, by means of a cookie cutter from a strip or plates of synthetic material adapted in particular from EVA (brand filed).

 As already indicated above, the essential characteristic of the process of manufacturing the sole assembly shown in the figures is linked to the fact that the insert 2 is placed in the recess 3 of the sole 1 immediately after the molding of the latter, that is to say when it is still hot: it is thus possible to take advantage of the shrinkage occurring during cooling to obtain optimal blocking of the insert 2.

 According to FIG. 2, the insert 2 is provided at its front part corresponding to the forefoot of the user with transverse slots 9, and, at its rear part corresponding to the socket and the camber, with perforations 10 distributed in two longitudinal rows; these elements 9 and 10 serve to increase the flexibility of the insert 2, and consequently to improve the comfort of the user.

 According to Figure 3, the aforementioned sole assembly, consisting of the sole 1 and the insert 2, is associated with a rod 11 which is preferably made of leather; at its front part corresponding to the user's forefoot, this rod is shaped so as to come to cover the sole assembly (sole 1, insert 2) on which it is bonded so as to define a half-first 12 of the type moccasin allowing the foot of the user to be in contact with the same leather as the upper 11 of the shoe, which is particularly comfortable.

 As shown in Figure 3, at the casing and the camber of the article, the rod 11 is folded so as to define a flange 13 which is glued in a conventional manner on the sole assembly; at this level, a half-first 14 shown in hatched form, in particular in a material such as polyvinyl chloride, comes to cover the sole assembly as well as the folded edge 13 of the rod 11.

 It is clear that the article represented in FIG. 3 is particularly comfortable for the user, on the one hand, since the sole of the foot is in contact with the same leather as the upper of the shoe, and, d On the other hand, that, the EVA insert (registered trademark) of constant thickness put in place on the lightening braces of the sole prevents the foot from feeling them.

Claims (8)

 1) Method for manufacturing an article of footwear and in particular an article of footwear of the moccasin type, characterized in that one molds by injection, by a known operation in itself a sole (1) relatively thick in one thermoplastic synthetic material, in particular polyvinyl chloride comprising a recess (3) in its central part, an insert (2) is made in parallel from a flexible and light synthetic material of dimensions corresponding to those of the recess (3) 7 then, immediately after the molding of the sole (1), when it is still hot, the insert (2) is put in place in the recess (3) so that the latter, coming to level, is perfectly maintained through shrinkage occurring upon cooling.  2) Method according to claim 1, characterized in that the recess comprises a bottom wall (4) essentially planar surrounded by side walls (5) of constant height (b) essentially perpendicular to the bottom wall (4).  3) Method according to any one of claims 1 and 2, characterized in that, during molding, the bottom wall (4) of the recess (3) is provided with lightening cells (7) separated by braces (8).  4) Method according to any one of claims 1 to 3, characterized in that the insert (2) is cut by means of a cookie cutter from a strip or plates of synthetic material of constant thickness (b) corresponding to the height of the side walls (5) of the recess (3).  5) Method according to any one of claims 1 to 4, characterized in that one provides the insert (2) with transverse slots (9) and / or perforations (10) in order to increase its flexibility.  6) Method according to any one of claims 1 to 5, characterized in that one fixes in particular by gluing, on the sole assembly defined by the sole (1) and the insert (2), at the level of the forefoot , a half-first (12) of moccasin type forming a body with a rod (11) in particular of leather which is mounted on the periphery of the sole assembly.  7) Method according to claim 6, characterized in that one glues a half-first (14) in particular of a synthetic material such as polyvinyl chloride at the casing and if necessary the camber of the article.  8) Footwear in particular footwear of the moccasin type obtained by implementing the method according to any one of claims 1 to 7, characterized in that it comprises a sole assembly consisting of a sole (1) externally relatively thick and comprising at its central part a recess (3) occupied by an insert (2) made of a flexible and light material coming to level.