STEAM-PERMEABLE MULTI-LAYER FIRE SOLE

The present invention relates to a composite insole which allows transpiration to occur

The present state of the art includes various solutions for manufacturing shoe accessories, in particular insoles which combine an aesthetic quality result with healthy hygienic conditions and comfort for user's foot.

More particularly, the use of new fabrics of synthetic material as a substitute for natural materials, e.g. cork, to manufacture inner soles, plantars or insoles has yielded important results in terms of improving hygienic and health conditions of the foot, in particular owing to their water-repellence and vapor-permeability properties.

However, there still remains the drawback that many synthetic materials used in said fabrics can cause unpleasant sensations, e.g. irritations or allergies, affecting feet having particularly sensitive skin, for which natural materials would be more suitable.

Patent application EP 693 259 discloses an inner sole which consists of one or more layers and which is integral with the shoe.

A filler material fills a recess in the surface of the loose insole and extends for part of its length. The recess can be at the ball of the foot, and formed in the surface of the sole towards the latter. The mating faces of the filler material and recess can be self-adhesive.

Another solution is disclosed in US 5 694 705.

Here, an insole is formed by the combination of two laminar bodies, one of split leather and another one of rubber material or the like, the latter being provided with knobs forming support projections for the foot.

The rubber body remains located under a window of the split leather body, the latter defining a wide perimetric raised strip with a transversal band in the area of the toe piece and an area set in the inside part of the shank. Both bodies can be connected by means of a seam or by means of gluing, to form a single body that will be superposed and fastened by any conventional system to a bottom support body to form a sole apt for receiving the assembly of the corresponding section of footwear. The split leather body provides the possibility of transpiration and knobs of the rubber body which provide therapeutic effects on the user's feet.

The main object of the present invention is to provide a composite and vapor-permeable insole, associating aesthetic and qualitative properties of a natural material with the transpiration advantages of synthetic material fabrics.

Another object of the present invention is to provide an insole having vapor-permeable properties confined to localized and preset regions.

Another object of the present invention is to provide an insole which allows transpiration to take place at a vapor-permeable portion localized in preset regions of said insole, preferably where foot perspiration is higher.

These and other objects which will become better apparent hereinafter are achieved, by a vapor-permeable composite insole, according to any of the following claims.

Further aspects and advantages of the present invention will become better apparent from the following detailed description of some currently preferred embodiments thereof, given by way of non-limitative example only, with reference to the accompanying drawings, in which:

1. Figure 1 is a plan view of the lower surface of an insole according to the invention;
2. Figure 2 is a plan view of the upper surface of the insole of Figure 1;
3. Figure 3 is a cross-sectional view of the insole, taken along the line III-III of Figure 2;
4. Figure 4 shows an enlarged-scale cross-sectional view of the insole, taken along the line IV-IV of Figure 2;
5. Figure 5 shows a lateral elevation view of the insole of Figure 1;
6. Figure 6 is a plan view of another embodiment of the insole of Figure 1; and
7. Figure 7 shows an enlarged-scale partial cross-sectional view, taken along the line VII-VII of Figure 6.

With reference to the above Figures, the reference numeral 1 designates an insole according to the invention, which can comprise a first layer 2, preferably made of flexible material, a second layer 3, made of relatively soft material, and a pad 4 made of vapor-permeable textile material.

The first layer 2 made of flexible material can be constituted by leather and/or imitation leather; layer 3 made of relatively soft material can be constituted by a synthetic material which is foamed to a greater or less extent depending upon softness requirements, e.g. PVC (polyvinyl chloride), polyurethane or EVA (ethyl vinyl acetate), whereas pad 4 made of vapor-permeable textile material can be constituted by a commercially available fabric known per se and constituted by woven fibers of a synthetic material, e.g. a polymer of inert plastics, such as polyester, polyamide, polypropylene or the like.

As more clearly shown in Figure 4, pad 4 can advantageously comprise three layers 6, 7 and 8 which form a textile net-like insert structure, i.e. a so-called "mattress" structure, in which the intermediate layer 7 is particularly yieldable by having a specific density lower than that of the two outer layers 6 and 8 so as to enhance the resilience properties of pad 4 and improve comfort of the insole 1.

The method of manufacturing the vapor-permeable insole 1 comprises first of all gluing, by means of an adhesive 11, a pad 4 made of vapor-permeable textile material to the lower surface 12 at a respective work area of the layer 2 of flexible material.

Preferably, a plurality of through holes 9, as shown in Figure 2, are formed at each work area of the layer 2, generally before the gluing operation, said holes being designed to be located, in use, at a respective vapor-permeable pad 4.

Advantageously, the through holes 9, which can have different dimensions from one another, are located at the ball or middle portion 19 of the insole 1, or in regions where user's foot rests frequently and where inevitably greater is foot perspiration.

The layer 2 of flexible material and the vapor-permeable pad 4, coupled and glued as described above, undergo injection-molding to obtain layer 3 of synthetic material. The molding operation thus delimits layer 3 of synthetic material within a preset border 14 and outside an internal area which is delimited by a border 15, is located at the vapor-permeable pad 4 and is slightly smaller than said pad, so as to partly overlap it along its entire border.

Injection-molding thus allows the synthetic material 3 to be uniformly distributed around the vapor-permeable pad 4, which is held so as to permanently adhere to the layer 2 of flexible material owing to the adhesive properties of the synthetic material, thereby generating a sort of "bonding" which ensures that the insole 1 is watertight.

By the injection-molding process it is also possible to obtain a layer 3 of synthetic-material-which has a suitable thickness distribution on the foot resting surface, whereby forming a relatively soft anatomic support for the insole 1. The portion 17 of the insole 1, which act as a supporting surface for the user's heel, can advantageously be thicker than the intermediate portion 18 and the portion corresponding to the ball portion 19 of the insole, and preferably has a stud 22 which delimits a recess 23 at the lower surface 24 of the insole 1 and a raised area 25 on the upper surface 26, on which the user's foot rests, the recess 23 and the raised area 24 being well radiused for joining their respective adjacent surfaces.

The above method may, of course, comprise the application, to the insole 1, of a vapor-permeable pad 4 also at the portion 17 thereof, where the heel of the foot rests (this solution is not shown in the said Figures).

In order to allow transpiration through the entire thickness of the insole 1, a plurality of holes 9 are then formed in the portion 17 of the layer 2 of flexible material and subsequently a pad 4 of vapor-permeable fabric is applied and glued to the lower surface 12 of the layer 2 of flexible material.

Since portion 17 of the insole 1 has a relatively high thickness, owing to the anatomic shape of the layer 3 of relatively soft material, it is preferable to adopt a vapor-permeable portion whose thickness is great enough to avoid formation of regions of discontinuity on the foot resting surface.

With the above-described method, therefore, there is obtained a composite insole, such as that shown in the above Figures, which is suitable for achieving the above specified objects, thereby ensuring in particular a suitable and localized vapor-permeable effect without affecting comfort and aesthetic appearance of the shoe to which it is applied.

Another embodiment of insole 1 is shown in Figures 6 and 7 and relates to an insole 1 provided with a pad 4 made of vapor-permeable material, which is arranged at the portion 19 of layer 2, which is formed with holes 9 and an insert 28 made of flexible material extending over a through opening 29 formed beforehand in the layer 2 of flexible material and not affected by the injection-molding of the layer 3 of relatively soft material.

Preferably, insert 28 comprises a membrane 30 having a peripheral border 31 held between layer 2 and layer 3 of the insole 1 and arranged to pass, in use, from a rest position, in which it is in relief with respect to layer 2, as shown in Figure 7, to a working position, in which it is compressed by the heel of the user's foot. The membrane 30 can have two concentric ridges 32 which extend inside the border 31 and are suitable for increasing its rigidity and acting, in use, as a return means so as to facilitate the passage of the membrane 30 from its working position to its rest position.

To withstand relatively intense pressure applied by the heel to the membrane 30 and to increase, in use, the effectiveness of the insert 28, the membrane 30 also has, at its lower surface 33, a plurality of pins 34 whose longitudinal extension is preferably perpendicular to both layers 2 and 3.

The insole 1 provided with the insert 28 as described above can thus be inserted in a shoe provided with a specific forced air circulation device and help improving the effectiveness of the processes of air sucking in, and discharging from, the inside of the shoe.

The materials and the dimensions may be various according to requirements.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.