EP0498965B1 - Moisture absorbing insole for shoes - Google Patents

Abstract

This insole is of the type comprising: - a first layer 10 intended to be located on the foot side and constituted in such a manner as to favour the passage of sweat from its upper face towards its lower face, - a second rigid layer 20 in contact via its upper face with the lower face of the first layer, this second layer delimiting cavities 23 opening out in the upper face of this second layer. According to the invention, the cavities constitute a volume for storing moisture and an absorbent material 30 is arranged inside these cavities. Moisture is thus stored by the absorbent material, which prevents its transfer towards the rest of the shoe and prevents moisture rising through the effect of foot pressure. <IMAGE>

Description

The present invention relates to a first cleanliness for shoes, in particular sports or leisure shoes, intended to remedy the problems caused by perspiration in the shoe.

It is currently known to use removable comfort and cleanliness firsts and consisting of a complex formed by an upper wear layer intended to allow perspiration to pass, an intermediate layer intended to absorb perspiration and a final waterproof layer.

In such a first, perspiration accumulates in the second layer but cannot be evacuated through the impermeable underside. The drying of such a first is therefore very long since it can only be done by running in the opposite direction of the humidity through the first layer.

In addition, such a sole construction offers a risk of backflow of water from the intermediate layer to the upper layer during walking because of the pressures thus generated on this layer.

By patent FR 2,629,692 was proposed a first of cleanliness and comfort corresponding to the preamble of claim 1 and comprising a flexible elastic absorbent layer for perspiration combined, on its underside, with a stiffening grid.

The stiffening grid thus defines cavities making it possible to ensure a certain "ventilation" and evaporation of moisture through this grid, and also constitutes a framework of the first of cleanliness and comfort. However, the "ventilation" thus produced is more or less effective and is not always possible, especially when the shoe is waterproof and very adjusted. Furthermore, such a first does not prevent a transfer of moisture to the rest of the shoe, this moisture remaining even when the first is removed and being difficult to remove.

This first does not solve the problems of rising humidity towards the foot under the effect of the pressures exerted on the first of cleanliness during walking or other, since the absorbent layer where the moisture is stored remains subjected to the pressures of the foot. FR 1 282 616 shows a sole consisting of a layer comprising cavities in which are accommodated moisture absorbing salts. This layer is also covered on each side by a sheet of permeable material allowing water to pass through. In such a construction, the problems of rising humidity are not resolved since the absorbent layer is subjected to the pressures of the foot and can desorb under the effect of these, the permeable material allowing the passage of water in the both directions. DE 35 16 653 shows a construction identical to FR 1 282 616 and therefore presents the same problems.

The purpose of the present invention is to remedy these drawbacks and to provide a cleanliness first allowing the perspiration produced during the exercise of a sport or walking to be absorbed, without the risk of rising humidity towards the foot, or towards the rest of the shoe, when applying pressure on this first.

Another object of the present invention is also to provide a first which can be dried quickly.

This object is achieved in the first according to the invention as defined in claim 1.

Indeed, the use of fixed volume cavities defined by the second rigid layer for the storage of moisture using absorbent material, makes it possible to avoid a transfer of moisture to the rest of the shoe and allows avoid rising damp due to the fact that these cavities are subjected to almost no pressure from the foot and that in any case the absorbent material does not "desorb" under pressure.

According to an advantageous embodiment, the cavities are formed by through holes passing through the second layer from its upper face to its lower face. In this way the drying of the first after use is very easy since the stored moisture can be evacuated directly at the lower end of the holes without having to cross the first layer again.

Advantageously, also the absorbent material consists of superabsorbent salts. Therefore there occurs between the upper and lower faces of the first layer a significant osmotic imbalance increasing the speed and the amount of water transferred from the upper face to the lower face of this layer.

According to a preferred embodiment, the absorbent material is retained inside the cavities by means of a membrane or the like, which may further include longitudinal moisture transfer means so as to allow moisture transfer from one zone of absorbent material to another, and therefore so as to allow absorption of moisture even in the event of local saturation of an zone.

• la figure 1 est une partielle en coupe longitudinale d'une première de propreté selon un premier mode de réalisation.
• les figures 2 à 5 sont des vues similaires à la figure 2 de premières de propreté selon d'autres modes de réalisation.

In any case, the invention will be better understood and other characteristics thereof will be highlighted with the aid of the description which follows with reference to the appended schematic drawing, representing by way of nonlimiting examples, several modes and in which:

• Figure 1 is a partial in longitudinal section of a first cleanliness according to a first embodiment.
• Figures 2 to 5 are views similar to Figure 2 of first cleanliness according to other embodiments.

The first cleanliness according to the invention shown in Figure 1 consists essentially of two layers, namely a first layer 10, located on the side of the foot 1 and intended to receive the latter on its upper face 11 and a second layer 20 which is in contact by its upper face 21 with the lower face 12 of the first layer 10 and which is intended to rest by its lower face 22 against the bottom of the shoe (not shown in the drawing).

The first layer 10 is formed so as to promote the passage of perspiration from its upper face 11 to its lower face 12 and is in this case made of a hydrophobic material 14, which may be in the form of a foam, crossed radially, that is to say from top to bottom, by drains 13.

The drains 13 are in this case formed by wicks or "bristles" completely passing through the first layer and therefore ensuring the passage of moisture from the upper face 11 to the lower face 12 of this first layer.

The wicks 13 can be made of a hydrophobic material and then ensuring the passage of water by capillary action. They can also be made of a hydrophilic material.

The second layer 20 has, in the example shown in FIGS. 1 to 4, the shape of a grid or lattice, that is to say the shape of a sheet of wires 25, 26 extending perpendicularly to each other. Such a layer 20 therefore delimits between the wires 25, 26 cavities 23 extending from one face to the other of the layer.

Of course, this second layer 20 could have a completely different shape and consist, for example, of a simple perforated sheet, the main thing being that this layer delimits cavities 23 opening at least into the upper face 21 of this second layer.

The second layer 20 also has a relatively rigid structure so that the cavities 23 can hardly be deformed during walking under the effect of the pressures exerted by the foot.

In the case of the grid shown in FIGS. 1 to 4, this rigidity is obtained by the use, for the wires 25, 26 constituting the grid, of a hard, non-deformable plastic material.

The cavities 23 thus defined constitute a non-deformable storage volume, inside which is placed an absorbent material 30, in this case superabsorbent salts such as crosslinked polyacrylates.

The superabsorbent salts 30 are retained inside the cavities 23 by a retaining membrane 40 disposed outside the second layer 20, that is to say outside the bottom face 22 and assembled, for example by a peripheral seam or by gluing to the assembly of the two layers 10, 20.

With such a construction of first cleanliness, the moisture generated during the exercise is transferred directly, through the wicks 13, to the cavities 23 where it is concentrated and absorbed by the absorbent salts 24 and does not extend to the rest of the shoe.

As these cavities 23 have an almost non-deformable volume and not subject to variations in pressure of the foot during walking, there is no longer any risk of rising damp under the effect of the pressures exerted by the foot. The construction according to the invention therefore provides a particularly comfortable and "dry" first cleanliness in use.

After use, it is enough to remove this first cleanliness and to dry it to remove the moisture stored in the salts. It will be noted that the use of highly absorbent salts makes it possible to avoid diffusion of moisture into the rest of the shoe and therefore preserves its longevity.

It will also be noted that the use of superabsorbent materials on the side of the lower face of the first layer contributes to creating a transfer of moisture of osmotic type through the first layer.

In such a type of transfer, the speed and the quantity of water transferred can then be increased as a function of the degree of absorption of the absorbent materials used as well as of the pressure difference existing between the top of the first layer 10 subjected to the pressures of the material. foot and the underside of this layer preserved from the pressure at least at the level of the cavities 23 of the second layer 20.

It will be noted that the retaining membrane 40 not only has a role of maintaining the absorbent salts inside the cavities 23, but that it also has a role of keeping these salts in contact with the wicks 13 of the first layer.

This retaining membrane 40 can also be used to ensure a transfer, either longitudinal, or transverse, or in both directions, from one cavity 23 to another, so as to allow the absorption of moisture even in the event of local saturation of the absorbent salts located in one zone, the humidity then being transferred by the membrane 40 to salts located in other cavities.

Such a characteristic can be obtained very simply by the use of a membrane having the shape of a knitted fabric or of a woven sheet capable of transporting moisture.

The membrane 40 can also be used to convey moisture to localized areas of absorbent salts.

In the example shown in Figure 1, the membrane 40 is disposed outside of the second layer 20, but it can also be arranged between the first and the second layer 10, 20, as shown in Figures 2, 3 and 4 so as to fill only the bottom of the cavities 23 of this second layer.

Such an embodiment is also advantageous because in this case the second layer 20 can be used to achieve adhesion of the first cleanliness on the bottom of the shoe. Such adhesion is particularly achieved when the second layer 20 is constituted by a grid as shown in FIGS. 2 to 4.

Of course, the choice of the position of the membrane will also be made according to the manufacturing criteria.

In the cases shown in FIGS. 1, 3 and 5, the first layer 10 provides both an upper wear layer function allowing water to pass through and a comfort function, namely of support-pressure distribution and possibly amortization. Such an embodiment is known per se and can be obtained very simply for example by a layer having a higher density at its upper face.

These different functions can also be dissociated at the level of the first layer, for example by providing a wear layer 50 (cf. FIG. 3) made of hydrophobic material on the upper face of the first layer 10, which no longer ensures that comfort and moisture transfer functions.

It will be noted that in the case shown in FIG. 4, a layer 60, preferably flexible, will preferably be fixed inside the shoe (not shown in the drawing) and therefore independently of the first cleanliness, on the one hand for do not interfere with the drying of the latter and, on the other hand, to allow better attachment and immobilization of the first in the shoe, the wires 25, 26 of the grid constituting the second layer 20 "hanging" in the material softer of this layer, which can also constitute an additional comfort layer 60, which is particularly advantageous in the case of a sports shoe.

Of course, such an attachment is only possible if the retaining membrane 40 is disposed between the first and the second layer as shown in this FIG. 4.

Of course, all the different functions could be dissociated and one could also produce a first cleanliness comprising, in addition to the first and the second layer, both the wear layer 50 and a comfort layer.

Finally, it will be noted that the cavities of the second layer 20 can also be constituted by blind holes 24 opening into the upper face 21 of this layer, as shown in FIG. 5, which makes it possible to avoid the provision of a membrane. retaining salts inside these holes.

Of course, the present invention is not limited to the embodiments described above by way of non-limiting examples.

Claims (15)

1. Insole for shoes, especially sport or casual shoes, comprising:

   - a first layer (10) intended to be located on the side of the foot and comprising means (13) of the draining type intended to promote the passage of perspiration from the upper surface towards the lower surface of this first layer,

   - a second rigid layer (20) in contact, by its upper surface, with the lower surface of the first layer, this second layer demarcating cavities (23, 24) ending in the upper surface of this second layer,

   characterized in that the cavities constitute a nondeformable moisture storage volume under the effect of pressures exerted by the foot, and wherein an absorbent material (30) is arranged inside of these cavities for moisture storage.
2. Insole according to claim 1, characterized in that the cavities are constituted by blind holes (24) arranged in the second layer.
3. Insole according to claim 1, characterized in that the cavities are constituted by through holes/clearance holes (23) crossing second layer (20) from its upper surface (21) to its lower surface (22).
4. Insole according to any of claims 1 to 3, characterized in that cavities (23, 24) extend in an essentially radial manner.
5. Insole according to claim 3, characterized in that second layer (20) essentially has the shape of a grid.
6. Insole according to claim 5, characterized in that the grid has a relatively rigid structure.
7. Insole according to any of claims 1 to 6, characterized in that a retention membrane (40) is arranged between the first and second layer while extending to the bottom of cavities (23) of the second layer, and wherein absorbent material (30) is arranged between the lower surface (12) of the first layer and retention membrane (40).
8. Insole according to claim 3, characterized in that a retention membrane (40) is arranged on the lower surface (22) of the second layer so as to retain the absorbent material inside cavities (23) of this second layer (20).
9. Insole according to any of claims 7 or 8, characterized in that membrane (40) allows a transfer of moisture from one cavity (23) to another.
10. Insole according to claim 1, characterized in that the first layer (10) is constituted of a hydrophobic material and comprises wicks (13), froming a drain, and extending essentially radially from its upper surface (11) to its lover surface (12).
11. Insole according to claim 10, characterized in that wicks (13) are made of a hydrophobic material and ensure drainage by capillarity.
12. Insole according to claim 10, characterized in that wicks (13) are made of a hydrophilic material.
13. Insole according to claim 1, characterized in that the first layer (10) is covered by a layer (50) of hydrophobic material, allowing the water to pass.
14. Insole according to claim 1, characterized in that it is treated against bacteria and/or fungi.
15. Insole according to claim 1, characterized in that the absorbent material (30) is constituted by super absorbent salts.

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