Breathable and waterproof sole for shoes

Abstract: A breathable and waterproof sole (10) for shoes, which comprises, at least along part of its extension, a lower waterproof component (11), which constitutes the tread; an upper component (12), with a supporting structure which has chambers (13) which are connected to openings (14) at least on the upper and edge surfaces; a membrane (19) which is impermeable to water and vapor-permeable and externally surrounds at least the outward-facing regions of the upper component (12). The lower (11) and upper (12) components and the membrane (19) are joined so as to form a seal at least in the regions where water infiltration is possible.

Description: The present invention relates to a breathable and waterproof sole for shoes. Shoes having rubber soles which can ensure particular practicality and comfort but do not allow the foot to breathe at all are already known and commercially available. Rubber soles with perforations in the tread and membranes superimposed on the perforated area and sealed in the peripheral regions have also been known for a few years. These soles allow correct breathing in addition to an effective exchange of heat and water vapor between the environment inside the shoe and the outside environment while ensuring the necessary impermeableness to external moisture and water. Other constructive solutions provide box-like rubber soles with perforations at the lateral edges which are internally obstructed by waterproof and breathable membranes which in this case also are joined peripherally so as to form a seal. These perforated soles, provided with waterproof and breathable membranes, have certainly constituted considerable improvements with respect to what was previously available. Nonetheless, there are still some practical drawbacks mainly due to the area occupied by the perforations, which though being sufficient has not yet reached its optimum extension. On the other hand, in the first case the number of perforations formed in the tread and the diameter of said perforations must be kept small in order to prevent pointed foreign matter entering through the perforations from penetrating until they damage or pierce the membrane. Such membrane is in fact continuously subjected to the compressive action of the foot, so that even a body which is not particularly sharp might easily cause damage. Soles are also known which internally comprise channels and systems for pumping air from the inside of the shoe to the outside by means of one-way valves. Pumping is actuated by the compression of the foot during walking. Accordingly, in this case the operation is merely mechanical and a stream of inflowing cold air is produced which in winter periods can be particularly unpleasant, since it causes rapid chilling of the feet, causing discomfort to the user. Moreover, the execution of the pumping devices integrated in the soles is expensive and complicated. WO 97/32497 discloses a sole as claimed in the preamble of claim 1. The aim of the present invention is to provide a breathable and waterproof sole for shoes which allows an optimum exchange of heat and water vapor with the outside, which ensures at all times an optimum internal microclimate as a function of the external microclimate, solving the above-mentioned drawbacks suffered by known types. Within this aim, an object of the present invention is to provide a sole in which the integrity of the breathable membrane is protected effectively while allowing adequate air circulation. Another object is to provide a sole which is able to keep the inside of the shoe dry even in the presence of condensation of the water vapor produced by perspiration due to excessive external humidity. Another object is to provide a sole which minimizes the problem of deposition of dirty material on the breathable membrane. Another object is to provide a sole which can be easily adapted to shoes of various kinds both for daily and sports use. Another object is to provide a sole whose cost is comparable to the costs of known soles. Another object is to provide a sole which can be manufactured with technologies and equipment which are already known in the field. This aim and these and other objects which will become better apparent hereinafter are achieved by a breathable and waterproof sole for shoes, as defined in claim 1. Further characteristics and advantages of the invention will become better apparent from the detailed description of some embodiments thereof, illustrated only by way of non-limitative example in the accompanying drawings, wherein: Figure 1 is a partially sectional view, in phantom lines, of a shoe provided with a sole according to the invention; Figure 2 is a cross-sectional view, taken along a transverse plane, of the sole of the shoe of Figure 1; Figure 3 is a partially exploded enlarged-scale perspective view of a detail of the sole of Figure 2; Figures 4 to 6 are views of shoes provided with respective embodiments of the sole according to the invention. With reference to Figures 1 to 3, a breathable and waterproof sole for shoes according to the invention is generally designated by the reference numeral 10 and comprises a lower component 11, which constitutes the wear tread, in this case made of waterproof material, for example a polymer such as polyurethane, rubber, PVC or the like. As an alternative, it is possible to use breathable materials, such as leather, waterproofed for example by means of an upper membrane which is joined perimetrically so as to form a seal, of the type which is impermeable to water and vapor-permeable. The sole 10 further comprises an upper component 12 with a supporting structure, which has interconnected chambers with outlets at least on the upper and edge surfaces. In the particular embodiment shown in the figures, the upper component 12 has a lattice-like structure made of plastics by molding, with chambers 13 which are interconnected by means of openings 14 provided in the partitions 15. As shown in Figure 1, a plurality of chambers 13 faces the lateral edge 16 and the upper supporting surface, on which in this case there is an insole 17 with through holes 18. The insole 17 can be conveniently made of leather or other suitable breathable or perforated material. As an alternative to what has been described, the upper component 12 can be formed for example by means of a block made of sponge-like open-cell material which is capable of bearing the weight of the user and of allowing the free passage of perspiration. For this purpose it is possible to provide materials such as latex foams or polyurethane foams of the open-cell type. It can also be convenient to integrate in the upper component 12 conventional impact cushioning systems, for example pads filled with air, gel, etcetera. The sole 10 further comprises a membrane 19 made of a material which is impermeable to water and permeable to vapor (such as the ones commercially available and commonly known by the trade-name Gore-Tex). The membrane 19, which can also be coupled to a light supporting fabric, not shown in the figures, wraps around the edge 16 of the upper component 12 at least in the regions that face outward and is joined thereto by perimetric gluing, taking care not to obstruct the chambers 13 with the adhesive. It is therefore possible to apply adhesive to the edges of the partitions 15 or to provide the membrane 19 with such an extension that it can be turned over, as shown in Figure 2, around the edge 16 and thus be glued in an upward region and in a downward region on the perimetric parts of the upper component 12. The two ends of the membrane 19 can be mutually joined at one of the partitions 15 (as shown in Figure 1) and then glued thereto so as to form a seal, or can be applied as a tape with heat or adhesives so as to provide a waterproof sealing joint. The sole 10 further comprises, in this case, a protective element 20 superimposed on the membrane 19 and constituted for example by a fine-mesh net or by a layer of breathable material which protects the membrane 19 from contacts with blunt objects which can rupture it. The protective element 20 can be applied by spot gluing or by full gluing in the regions of the membrane that are folded back around the edge 16, so that on the edge 16 there is no adhesive which compromises breathability. As an alternative, the membrane 19, optionally with its protective element 20, can be arranged as a mold insert onto which the upper component 12 is overmolded so as to ultimately constitute a sealed monolithic element. It should also be noted that the membrane can be provided so as to make it difficult to pierce, for example by using aramid fibers or other material as a support. The membrane can be made of hydrophilic polymer, and in this case can be integrated in a support which is permeable to water and comprises fibers of materials, which are technologically per se known, as composites. In this case, i.e., if the membrane 19 is capable of withstanding blunt objects thanks to its very structure, the presence of the protective element 20 might not be necessary. The upper component 12 is joined hermetically to the lower component 11 according to known gluing methods, or the complete sole 10 can be manufactured by means of individual or multiple injections and by inserting, as an insert, the membrane 19 (optionally with its protective element 20) or the membrane 19 with the already-prepared upper component 12. It is particularly important to provide a hermetic joint between all the elements in contact in the regions where water infiltration is possible. The upper component 12 acts as a container which is closed at the bottom by the lower component 11 and is open perimetrically with a breathable and waterproof band. The assembly is conveniently assembled to an upper 21 in manners known in the shoemaking field, taking care not to obstruct the passage of vapor from the inside of the shoe toward the chambers 13. With reference now to Figures 4 to 6, said figures show respective embodiments of the invention, in the first of which the upper component 112 has a smaller extension than the lower component 111 and is extended in particular at the heel region. In this case, appropriately provided channels, not shown in the figure, can be provided in an upward region in the lower component at the forefoot and it is possible to provide holes in the inner sole so that perspiration can pass easily from toe to heel. In Figure 5, the lower component 211 and the upper component 212 are monolithic so as to form the heel. The sole 10 thus provided is fully impermeable and breathable along the entire edge region of the upper component 12 without thereby reducing the functionality of said sole (impact absorption, flexibility, light weight, et cetera). From the point of view of operation, the foot compresses the upper component 12, pushing perspiration out of the shoe after the moist air has entered the upper component 12 from the holes of the insole 17. By using a breathable and waterproof membrane of the type that also allows air to exit from inside, a considerable increase in the exchange of air in said shoe is achieved, which is very useful in products for athletes. The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims. All the details may further be replaced with other technically equivalent elements. Thus, for example, the lower component 11 can be conveniently constituted by a perforated lower layer with, in an upward region, a membrane which is breathable and waterproof (with or without a light supporting fabric), joined hermetically thereto in the perimetric regions. The membrane can be conveniently provided in a downward region with a protective layer. This occurs if it is necessary to further increase the possibility of exchange with the outside. In practice, the materials used, so long as they are compatible with the contingent use, as well as the dimensions, may be any 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.

Claims: A breathable and waterproof sole for shoes, comprising, at least along part of its extension: a lower waterproof component (11), which constitutes the tread; an upper component (12), with a supporting structure which has interconnected chambers (13) with openings (14) at least on the upper and edge surfaces; a membrane (19) which is impermeable to water and vapor-permeable and externally surrounds outward-facing regions of said upper component (12); said lower (11) and upper (12) components and said membrane (19) being joined so as to form a seal at least in the regions where water infiltration is possible, characterized in that said membrane is perimetrically sealed to said upper component so as to obtain a waterproof connection, and in that said membrane (19) wraps around the edge (16) of said upper component (12) at least in the regions that face outward and is joined thereto by perimetric adhesive bonding, while leaving free of adhesive and unobstructed said chambers (13). The sole according to claim 1, characterized in that it comprises a breathable or perforated protective element (20) which covers at least the regions of said membrane (19) that face outward and is joined so as to form a seal to said upper (12) and lower (11) components and to said membrane (19), where it is interposed between two of said components, at least in the regions where water infiltration is possible. The sole according to claim 1, characterized in that said lower component (11) that constitutes the tread is made of a polymer such as polyurethane, rubber, PVC or the like. The sole according to claim 1, characterized in that said lower component (11) that constitutes the tread is made of breathable materials such as leather, rendered waterproof for example by means of an upper membrane, joined perimetrically so as to form a seal, of the type which is impermeable to water and vapor-permeable. The sole according to claim 1, characterized in that said lower component (11) that constitutes the tread is constituted by a perforated lower layer on top of which there is an upper membrane which is impermeable to water and permeable to vapor and is joined thereto so as to form a seal in the perimetric regions. The sole according to claim 1, characterized in that said upper component (12) has a lattice-like structure and is made of plastics, with partitions (15) which delimit said chambers (13), said chambers (13) being interconnected by way of said openings (14) provided in partitions (15). The sole according to claim 6, characterized in that a plurality of chambers (13) faces the lateral edge (16) and the upper supporting surface. The sole according to claim 1, characterized in that said upper component (12) is formed by way of a block of open-cell spongy material capable of bearing the weight of the user and of allowing perspiration to pass freely. The sole according to claim 8, characterized in that said spongy material is latex foam or polyurethane foam of the open-cell type. The sole according to claim 1, characterized in that impact cushioning systems, such as pads filled with air, gel, or the like, are integrated in said upper component (12). The sole according to claim 1, characterized in that said membrane (19) is coupled to a light supporting fabric. The sole according to claim 1, characterized in that said membrane (19) includes aramid fibers or equivalent material which is difficult to pierce, as a support. The sole according to claims 1, characterized in that said membrane is made of hydrophilic polymer integrated in a support which is permeable to water and comprises fibers of materials which are technologically known as composites. The sole according to claim 1, characterized in that said adhesive is applied to the edges of said partitions (15). The sole according to claim 1, characterized in that said membrane (19), which is folded upward and downward, is glued in an upward region and in a downward region to the perimetric parts of said upper component (12). The sole according to claims 1 or 6, characterized in that the two ends of said membrane (19) are mutually joined at one of said partitions (15) and are then glued hermetically thereto, or are applied as a tape by heat or adhesive sealing so as to form a waterproof sealing joint. The sole according to claims 1 or 2, characterized in that said protective element (20) is constituted by a fine-mesh net or by a layer of breathable material, which protects said membrane (19) against contacts with blunt objects which can rupture it. The sole according to claim 17, characterized in that said protective element (20) is applied by spot gluing. The sole according to claim 17, characterized in that said protective element (20) is applied by fully gluing the regions of the membrane (19) that are folded around the edge (16) of said upper component (12), so that said edge (16) is free of adhesive which may compromise breathability. The sole according to claims 1 or 6, characterized in that said membrane (19), optionally with said protective element (20), is provided as a mold insert onto which said upper component (12) is overmolded, so as to finally constitute a single sealed element. The sole according to claim 1, characterized in that said upper component (12) is joined, so as to form a seal, to said lower component (11) according to known adhesive bonding systems. The sole according to claims 1 or 6, characterized in that it is manufactured through individual or multiple injection-molding operations, and comprises as an insert said membrane (19), optionally with said protective element (20). The sole according to claim 1, characterized in that it is manufactured through individual or multiple injection-molding operations, and comprises as an insert said membrane (19), with said upper component (12) already prepared. The sole according to claim 1, characterized in that said upper component (12) has a smaller extension than said lower component (11), with channels being provided in the free regions of said lower component and holes provided in an upward region in said lower component, so that perspiration can flow freely among the various regions.

Inventors: POLEGATO MORETTI MARIO, POLEGATO MORETTI, MARIO
Applicants: GEOX SPA, GEOX S.P.A.
Application year: 2001
Main classification: A43B7
IPC codes: A43B7, A43B13