EP1114589A1 - Shoe with viscoelastic inner lining - Google Patents

Abstract

The boot has a lining (3) comprising in at least one area a viscoelastic material (6) bound to a flexible sheet (7) which contacts the foot. The viscoelastic material consists of a thin layer of polymer gel of density 1 - 2, with delayed elasticity and an elongation at break greater than 400, preferably 700 - 900 %.

Description

The invention relates to shoes in general, whether they have a flexible or rigid upper, and relates to an inner lining of their rod intended, among other things, to contribute to the comfort of the foot and ensuring contact with it for its maintenance.

Conventionally, and depending on the type of shoe, the interior lining is fitted either on a cushioning element or interposed comfort cushion, or directly on the rod. More specifically, in the case of shoes whose upper is relatively rigid, such as ski and mountaineering boots, the cover is mounted on the inside of an element of padding such as a removable or fixed liner which is interposed between the upper and the foot. Through against, in the case of sports shoes with a flexible upper, such as tennis, basketball, running, ... etc., the interior lining is directly mounted on the rod.

Furthermore, with regard to respecting as best as possible the morphology of the foot for the comfort of it, the interior lining of these various types of shoes presents almost generally one or more relatively flexible pieces of fabric or leather and / or elastic on the side adjacent to the foot. Conventionally, these pieces of fabric are composites that result from coating or bonding very low density foam on the back of a textile. They are thus able to conform to the rod and / or the element of padding on which they are mounted, and also able to deform later on the foot when the shoe is closed on the latter. The pieces of fabric also provide soft to the touch and a pleasant feeling when putting on. They are revealed by against ineffective in dispersing or attenuating the slightest overpressure or the slightest hard point between the upper and the foot because of their low density and their great facility to compress.

By way of example, mention may be made of American patents 3,977,098 and 5,765,296 which describe, respectively, a shoe with a rigid upper and a shoe with a flexible upper provided an interior covering having on the side contiguous to the foot at least one piece of flexible fabric as previously discussed.

As is evident from this state of the art, the contact of the interior trim with the foot is more or less intimate depending on whether the upper of the shoe is itself flexible and deformable and / or that the padding element interposed between the rod and the foot can conform to the foot. For example, US patent 3,977,098 precisely describes a solution to adjust / adapt a cushioning element, such as a slipper, on the foot inside, covered with a layer of fabric. As taught, side wedges, possibly in the form of impermeable packages containing a material deformable, are inserted into pockets located on the outside of the padding to adjust the width of the footwear volume and thus ensure the holding of the latter in the rigid upper of the shoe.

This way of proceeding by a lateral wedging intended to move the padding in direction of the foot requires that this padding be made of a material easily compressible if it is the adjustment to the foot which is sought, or else it is carried out in one relatively firm material if it is the hold of the foot which is privileged. Indeed, a padding given in can not be both easily deformable, to wrap the foot, and firm, to hold it without flutter.

In this case, this problem is partially solved by the fact that the padding, which is polyurethane or foam rubber, therefore compressible, is made from a blank forming a pair of side panels and the fact that it is a lateral wedging in the ankle area. Indeed, given that the draft of the padding originally has shapes roughly corresponding to those of the foot, it is not necessary to firmly tighten the padding on the foot to hold it because the most protruding from the latter are housed in the blank; moreover, being essentially solve a lateral timing problem, this does not imply an intimate adjustment of the padding because an approximate approximation of the side panels of its blank on the foot is sufficient to ensure its adjustment to the width of the latter. This calibration process and / or adjustment is therefore satisfactory but within a strict limit because the padding does not does not ensure a wrapping / adjustment faithful to the shape of the foot; however, the absence of intimate contact with the foot considerably fades the tactile perceptions of the latter and consequently disrupts the gesture of the wearer of the shoe, especially when it comes to shoes which are subject to materials or accessories necessary for a practice sports such as skis, roller or ice skates, crampons, ... etc.

In addition, the small thickness of the pieces of fabric which cover the padding, as well as their texture, have no capacity to absorb any protruding part of the foot and no ability to disperse the pressures that padding can apply locally to prominent parts of the foot. Again, when using the shoe and depending on the loads on the foot, the movements of the latter relative to the padding, despite their low amplitude, are not accompanied by these pieces of fabric. This results in rubbing, which is very often the cause of blisters, irritations and burning sensations.

In the example of the shoe described in US Patent 5,765,296, the problem of holding the foot and adjusting the interior trim on the foot is carried out different because it is a shoe with a flexible upper provided with foam padding. In Indeed, in this type of shoe, it is the combination of the flexibility of the upper, the compressibility padding and the clamping force applied to the lacing which conditions the foot hold and wrap in the shape of the latter. Of course, the pieces of fabric that cover the interior trim on the side adjacent to the foot also participate in the wrapping of the foot, and are, for this purpose, made of a material resembling a felt flexible to facilitate the passage of the foot in the shoe. However, as in the case of padding described and taught in US Patent 3,977,098, these pieces of fabric have too thin and too soft and felted to contribute to the hold of the foot in the shoe as well as to absorb any protruding part of the foot. In addition, due to their intimate connection with the upper of the shoe, the deformations that the foot imposes on this last during walking, running, jumps, ... etc., and their repetition, cause term delamination and / or takeoff of these pieces of fabric. This deterioration which results from the pressure of the pieces of fabric against the foot and their impossibility of accompanying this in these micro displacements relative to the rod is also indicative of friction which is at the origin of irritations, overheating, blisters, ... etc.

The object of the present invention is to remedy the drawbacks of interior linings known and aims in particular to provide an interior covering which is suitable, by a layer adjoining the foot, conforming to small protrusions and / or protrusions extending to the surface of the latter and to accompany the foot in its micro displacements relative to the rod of the shoe.

According to the invention, the layer contiguous to the foot has, over at least one determined area, a structure composed of a viscoelastic substance mounted on a flexible film and stretchy, such as a fabric for example. This structure constitutes the equivalent of a double skin thanks, in particular, to the thinness and the great capacity of elastic deformation of the viscoelastic substance combined with a low elastic modulus; these different characteristics give the viscoelastic substance, and thus the structure of the layer adjacent to the foot, a typical behavior of a so-called "delayed" elasticity and a natural tendency to press on the foot like a viscous gel conforming to the small prominences of the latter.

In this way, the micro movements of the foot relative to the upper of the shoe are essentially absorbed by the viscoelastic structure of the layer adjacent to the foot. The layer thus structured in fact constitutes the interface element between the foot and the upper of the shoe which, if fitted on a padding, filters vibrations, shocks, ... etc., absorbs small displacements, and to some extent avoids putting the contribution of the foot while preserving the transmission of tactile sensations.

According to one characteristic, the interior covering comprises a layer contiguous to the foot made up, on at least one specific area, of a structure composed of a substance incompressible viscoelastic having a low elastic modulus and a flexible film and elastic which can be a woven or nonwoven material on which the latter is fixed. According to a construction method the viscoelastic substance is contained in an envelope made using a flexible and elastic film.

The viscoelastic substance is, for example, a gel of polymers of density included between 1 and 2, and whose behavior is characterized by a "delayed" elasticity and by a elongation capacity at break greater than 400%, and preferably of the order of 700 to 900%. According to another characteristic, the viscoelastic substance has a hardness, or resistance to deformation and penetration, between 15 and 45 Asker 'C', and preferably between 25 and 30 Asker 'C'. This hardness is measured with Asker hardness testers intended for substances classified in soft rubbers and plastics, including flexible cellular materials and elastomers, according to standard SRIS 0101 (Society of Rubber Ind. Japanese Standard). Thanks to these characteristics, the viscoelastic substance can deform under the effect of a stress in the manner of a viscous fluid, because its capacity elongation is important, and can return to its original shape like a spring but this after a certain period of time after the stress has ceased because its modulus of elasticity is weak.

In fact, this gel-like substance behaves like a viscous product for slow stresses, and as an elastic product for rapid stresses.

According to a preferred embodiment, the viscoelastic substance is produced in the form of a thin sheet in a thickness close to 1 millimeter, and at most of the order of 5 millimeters.

Its connection with the flexible film is obtained by gluing, stitching, welding, ... etc.

These different characteristics of viscoelasticity, thickness and bonding on the film flexible give the structure a flexibility comparable to that of the pieces of fabric used traditionally and a certain homogeneity and stability. In particular, creep is avoided by gravity of the viscoelastic substance while allowing its deformation under pressure when the upper of the shoe is tightened on the foot.

According to one embodiment, the contiguous layer of the foot is provided with a structure composed of a viscoelastic substance bonded to a flexible film on at least one area of the foot with bony prominences.

According to another embodiment, the layer contiguous to the foot comprises several zones which are each provided with a structure composed of a substance viscoelastic attached to a flexible film.

According to a construction variant of this embodiment, the structure composed of a viscoelastic substance bonded to a flexible film has a thickness different from an area determined to another determined area. For example, in areas where prominences bones of the foot are very marked, it is a structure where the viscoelastic substance is relatively thick, for example 4 to 5 millimeters, which is used. In this way, the location of pressure points is avoided thanks to the conformation of this structure on a large contact area.

The invention will moreover be better understood by referring to the description which follows in reference to the appended schematic drawings showing, by way of example, two modes of production.

FIG. 1 illustrates, in perspective view, a shoe of the rigid shell type equipped with a comfort padding with an interior covering according to the invention.

FIG. 2 represents the shoe of FIG. 1, seen in cross section along II-II, with the user's foot positioned inside.

Figure 3 shows, in section, a detail of the interior trim of the shoe.

FIG. 4 illustrates, in perspective view, a shoe with a flexible upper also equipped with a interior covering according to the invention.

FIG. 5 is a cross-sectional view along V-V of the shoe of FIG. 4.

FIGS. 6 and 7 represent a method of constructing an interior covering, or lining, before mounting on the upper of a shoe, FIG. 6 illustrating the covering developed flat, and Figure 7 a section along line VII-VII of the trim of Figure 6.

The boot illustrated in FIGS. 1 and 2 is a ski boot with a rigid upper 1 which is provided with comfort padding 2, constituted by a slipper, which is interposed between the foot 4 of the user and the rod 1. This padding 2 is produced, in a manner known per se, in a microcellular material, with a density less than 1, more or less compressible such as polyurethane or foam rubber, and has an outline of a footwear volume corresponding approximately to that, standard, of a 4 foot in a given size.

According to an essential characteristic, the padding 2 is covered by a covering interior of which a layer 3, contiguous to the foot 4, is provided with a structure 5 where a sheet thin of a viscoelastic substance 6 with low elastic modulus is bound to a flexible film and elastic 7. This viscoelastic substance 6 is constituted for example by a gel of polymers with a density between 1 and 2, and its behavior is characterized by a elasticity "delayed" and by a capacity of elongation at break greater than 400% and preferably between 700 and 900%. Its hardness, measured with an Asker durometer, is between 15 and 45 Asker 'C', and preferably between 25 and 30 Asker 'C'. On the plan dimensional, the thin sheet of viscoelastic substance 6 has an approximate thickness of 2 millimeters and can reach 5 millimeters.

By these provisions, the structure 5 of the layer 3 retains a substantially flexibility comparable to that of traditionally used fabric pieces, that is, it can cover the padding 2 by faithfully following its shapes and accompanying its deformations subsequent when the rod 1 is tightened to close the shoe on the foot 4 of the user. On the other hand, due to its incompressibility combined with its great elongation capacity at the rupture and its density greater than that of the padding 2, this structure 5 can be conform to the small prominences of the foot not taken into account by the draft of the volume footwear offered by the padding 2. Furthermore, when the latter is pressed on the foot 4, by means of the rod 1 when the shoe is closed, the viscoelastic substance 6 of the structure 5 deforms in the manner of a viscous fluid, becoming thinner at the location of the greatest pressures and thickening in the surrounding space subjected to lower pressures. This behavior results in intimate contact between the structure 5 of the layer 3 and foot 4, and thus an increased feeling of holding which allows the user to shoe to have a more precise gesture.

There is in fact a layer 3-5 relatively dense and incompressible in contact with the foot 4 and a padding element of lower density and compressible between this layer 3-5 and the rod 1; in this way, layer 3, with its structure 5, plays the role of a double skin because it conforms faithfully to the foot and its high elasticity allows it to support micro movements of the foot relative to the upper 1 of the shoe or even relative to the padding 2. This avoids friction which is likely to occur between the film flexible 7 and foot 4.

In the example illustrated in FIGS. 4 and 5, the interior covering comprising a layer 3 with a structure 5, as described with reference to Figures 1, 2 and 3, is suitable for a shoe with flexible upper 11. In this case, the layer 3 with structure 5 is directly mounted on the flexible rod 11 whose outline it follows. Preferably, given the great ease of the flexible upper 11 to be adjusted on the foot of the user when the shoe is closed and for weight issues, structure 5 has a viscoelastic substance which is under form of a thin sheet whose thickness is of the order of 1 millimeter. We preserve the so the ease of adjustment of the upper 11 of the shoe without weighing it down too much.

Of course, nothing prevents the implementation on the flexible rod 11 of a padding of comfort 15, for example on the upper edge of the foot entry opening, and dressing or no, this padding 15 with the structure 5 of the layer 3.

Figures 6 and 7 show a method of constructing an interior covering, one of which layer 3 provided with a structure 5 is associated with a support piece 22 which can constitute a comfort padding. The latter, possibly shaped to fit the substance viscoelastic 6, is fixed to the flexible film 7 of the structure 5, for example, by bonding films hot melt. In order to facilitate the mounting of this interior covering on the rod of a shoe, not shown, the zone 23 intended to be sewn and / or stitched, such as the border, is devoid of viscoelastic substance 6.

Many other adaptations of a structure 5 near the foot are possible without for this to depart from the scope of the invention. So the viscoelastic substance 6 of structure 5 can be accommodated, for at least part, in comfort padding 2 on the side facing the user's foot 4. In addition, the layer 3 contiguous to the foot can be provided with a structure 5 composed of a viscoelastic substance linked to a flexible film 7, or linked to any other textile having equivalent properties, on only one area of the foot having bony prominences.

Still, the contiguous layer 3 of the foot can comprise several specific zones provided, each of a structure 5 composed of a viscoelastic substance 6 fixed to a flexible film 7 or a textile, and this structure may have a thickness different from an area determined to another specific area. As an example, structure 5 could be located in areas 12 and 13 corresponding to the malleoli 12 'and 13' of the foot 4.

Finally, a layer 3 provided with a structure 5 can obviously constitute the interior covering. a tongue of comfort padding or a slipper, and / or also the tongue 14 from the upper of a shoe.

Claims (10)

Shoe whose upper has an inner covering having a layer (3) contiguous to the foot of the user who is provided, in at least one determined area, with a structure (5) composed of a viscoelastic substance (6) linked to a flexible and elastic film (7), the latter being in direct contact with the foot, characterized in that the substance viscoelastic (6) is incompressible and has a low elastic modulus and is in the form of a thin sheet of a gel of polymers of density between 1 and 2, and the behavior is characterized by a "delayed" elasticity and by an elongation capacity at failure greater than 400%. Shoe according to claim 1, characterized in that the viscoelastic substance (6) is characterized by an elongation capacity at break of between 700 and 900%. Shoe according to any one of claims 1 or 2, characterized in that the viscoelastic substance (6) is obtained in a thickness between 2 and 5 millimeters. Shoe according to any one of claims 1 to 3, characterized in that the viscoelastic substance (6) is contained in an envelope produced using a flexible film and elastic (7). Shoe according to any one of claims 1 to 4, characterized in that the interior covering covers a comfort padding (2, 22) which is interposed between the viscoelastic substance (6) and the upper of the shoe. Shoe according to claim 5, characterized in that the viscoelastic substance (6) is partly housed in the comfort padding (2, 22) on the side facing the foot the user. Shoe according to claim 6, characterized in that the layer (3) of the covering interior which is contiguous to the foot has several specific zones which are provided, each of a structure (5) composed of a viscoelastic substance (6) bonded to a flexible film and elastic (7). Shoe according to claim 7, characterized in that each of the zones determined has a structure (5) which, composed of a viscoelastic substance (6) linked to a flexible and elastic film (7), is of different thickness from one determined area to another specified area. Shoe according to any one of claims 1 to 8, characterized in that the viscoelastic substance (6) has a hardness between 15 and 45 Asker 'C'. Shoe according to any one of claims 1 to 8, characterized in that the viscoelastic substance (6) has a hardness between 25 and 30 Asker 'C'.

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