Self-cleaning, shock-resistant sole for ventilated shoes

Abstract: A shoe sole (A) comprising a fixed insole (B) provided with a series of holes, wherein there is provided a plurality of resilient hollow air chambers extending through the whole thickness of the sole, said chambers having an upper portion with hemispheric shape and circular plan which supports the fixed insole, and a lower portion forming the tread. The shape of such air chambers or spacers is similar to that of an igloo with a central hole (1, 1') at the top. In order to perform a shock-resistant action there are provided conical protrusions (6) projecting from the base of each igloo towards the respective upper hole (1) so that when the walls (2, 5) are deflected by the user's weight, each protrusion (6) will occlude the corresponding hole (1) before all of the air contained in the igloo escapes.

Description: The present invention relates to a sole capable of providing an effective ventilation and massage of the user's foot during walking. There are known to be a number of moulded soles for shoes comprising resilient chambers located both on the upper surface of the sole so as to contact the insole underneath the foot and projecting downwards from the sole so as to act as a tread. Such chambers are indeed air chambers communicating with the inside of the shoe and allowing the foot to be more or less effectively ventilated during walking in order to oppose to the troublesome, not very hygienic perspiration of the foot. They also provide a more or less strong cushioning effect because of their deflection and expansion back to their original state during walking. However, in spite of the several solutions brought forward the results are not very satisfactory since a greater foot ventilation would be desirable, avoiding at the same time an excessive deflection of the air chambers which could give the user troubles. Moreover, there arises the need of an air circulation not only limited to the ejection and suction always of the same air but providing a real air change. EP-A-0780063, falling within the terms of Article 54(3) EPC, discloses a shoe sole having a series of hollow, flexible protuberance extending only from the upper surface of a sole layer. The series of hollow, flexible protuberance have one or more holes to communicate with the interior of the shoe. The aim of these protuberances is to obtain a forced ventilation in the foot when the user walks. From WO-A-92 01398 a sole is known having a plurality of sealed air cavities each of which act as energy storage device. The cavities are surrounded by a filler injected when the sole is in a mould. In order to avoid the penetration of filler through an opening extending to the upper face of the sole, there are provided means for sealing the opening of each cavity during the forming of the sole. DE-U-83 12 206 describes a shoe sole unit of resilient material, with a plurality of cavities opening to the top surface of the sole unit and interconnected by a series of channels. A bulge is provided on the bottom surface of the sole unit at the location of each cavity. Thus, pressure exerted by the foot on any bulge expels air from the associated cavity, and the action of walking pumps air from one cavity to another cavity along the channels and in this way absorbs the shocks of impact of the foot with the ground. At the same time, perspiration from the foot of the wearer can pass through the pores of an insole made of suitable permeable material, which is in direct contact with the channels. US-A-3 533 171 discloses a shoe sole having a plurality of semi-circular cavities which are not provided with a central hole at the top. The present invention seeks to overcome the above problems and provides a shoe sole of the above-mentioned type in which the arrangement of the air chambers is not limited to the upper or lower side of the sole anymore but takes up the whole thickness of the sole, thus also ensuring an effective shock-resistant action against any soil unevenness on which the foot is laid besides enough ventilation to the benefit of the user's foot. A second object of the present invention is to provide a sole of the above-mentioned type wherein the air chambers are provided with means capable of exerting a beneficial, tonic action causing the user's feet to be massaged in a more significant manner than heretofore known. Still another object of the invention is to provide a particularly light, cost-effective shoe sole of simple, sturdy construction being affected by no problems caused by any of its mechanical parts and/or delicate components. Finally, another object of the invention is to provide a shoe sole wherein the tread is capable of expelling any material stuck on it during walking. All of the objects listed above are accomplished according to the present invention by a shoe sole comprising a plurality of resilient hollow air chambers extending through the whole thickness of the sole, said air chambers being dome-shaped with a central hole at the top, have an upper hemispherically shaped portion with a top plane suitable to support a fixed perforated insole, and a lower portion forming the tread and extending below support members connecting the plurality of air chambers. In a preferred embodiment of the invention, a conical protrusion projecting towards the top central hole and capable of plugging the same during the deflection is provided on the inner base of each air chamber. The form of the air chambers having a thickness gradually decreasing towards their upper portion as well as the selection of materials capable of being resiliently deformed is such as to create an air circulation with air change under the user's foot sole during walking. The sole's performance as it was described so far may be summarized as follows: the movement during walking with repeated cycles of the user's weight loading onto and unloading is used to create an air circulation under the foot. In fact each single air chamber exerts a pumping action due to its resilient deformation. During the user's weight loading step, the air chambers deflect and deform and their reduction in volume causes the air contained therein to be forcibly expelled through the top central hole. During the following user's weight unloading step, the consequent resilient return causes an air suction with the ensuing filling of the air chambers with the air from the shoe. It should be appreciated that the air circulation is not limited to an expulsion and a suction of the same air to the detriment of a real air change. In fact the lower surface of the fixed perforated insole resting on the air chambers forms a valve which causes, in the expulsion step, the air to push the edge of the top central holes against the perforated insole preventing the air from escaping sideways and forcing the air to reach the inside of the shoe and the user's foot. In this way, air is prevented from lingering in the gaps among the air chambers. In other words, once expelled the air is conveyed through the transpiring frame of the perforated insole. During the suction step, the shape and the thinness of the edge or lip of the top central holes of the air chambers allow fresh air to enter the latter through the openings in the vamp that communicate with the outside. According to trials and the basic laws of enthalpy, it should be appreciated that a real air circulation is established as described above. Trials carried out on different kinds of shoes have shown that the volume of circulated air is more than good enough to guarantee an effective ventilation of the foot and advantageously reduce the effects of its perspiration. Another advantage of the invention is that the air chambers provide a pleasant, effective massage to the sole of the foot so that blood circulation results to be improved. All the above mentioned advantages have been obtained by providing a shoe-sole according to the annexed claims. A better understanding of the invention will ensue from the following detailed description with reference to the accompanying drawings which show only by way of example some preferred embodiments. In the drawings: Figure 1 is a partially sectioned side view of a shoe without a sole; Figure 2 is a cross section of a first embodiment of the sole according to the invention; Figure 3 shows a detail of the sole of Figure 2; Figures 4-5 and 6-7 similar to the preceding Figures 2 and 3 show a second and a third embodiment of the invention, respectively. With reference to Figure 1, the sole according to the invention is capable of being applied to a winter or summer shoe A, with or without shoestrings which may also be a boot or a sandal provided with a perforated insole constituted by a fixed insole B having a series of holes. Such fixed insole B is covered with a so-called cleaning sole C which is perforated. According to the invention, the air blown in by the sole during walking can flow through the perforation so as to easily reach the inside of the shoe. With particular reference to Figures 2 and 3, the sole according to the invention essentially consists of a peripheral rib 14 and a tread 10. The vamp is anchored to said rib 14 by conventional gluing and, if necessary, sewing. In a first embodiment the tread includes a number of air chambers which monolithically extend towards the upper portion of the sole, i.e. that portion on which the perforated fixed insole of the shoe rests. Each dome-shaped air chamber having a central hole at the top, hereafter called "igloo", has a tread 10 provided with a central portion 7 shaped as a suction cup. Obviously, such a shape is not the only possible form of that portion as the tread may show different patterns in order to have an antislip function. The igloos are structurally bound to one another to form the sole by support members 4. The sole in top plan view shows a series of half-spheres 2 provided with central holes 1 at their upper side. When the foot causes them to be deflected during walking, the half-spheres exert a massaging action and at the same time blow air in. In the embodiment described a large amount of air is blown into the air chambers or igloos as the latter have a remarkable volume 9 as a consequence of their lower walls 5 of small thickness resting directly on the ground and acting as a tread. Such "igloos" give a considerable comfort to the foot which always rests on a pleasantly soft surface. In order to also perform an advantageous shock-resistant action there are essentially provided conical protrusions 6 projecting from the inner base of each igloo towards their respective top hole 1. In this way, when the half-spheres 2 and lower walls 5 are deflected by the user's weight, each protrusion 6 will occlude the corresponding hole 1 before all of the air in cavity 9 of the igloo escapes. Under these circumstances it is evident that each igloo acts as an airtight hollow body in which the air is the cushioning resilient element. The operation has a number of steps: one step of soft deflection with simultaneous air blowing into the shoe, a following airtight sealing before the air chambers have been completely emptied, the ensuing resilient cushioning shock-resistant effect, and the subsequent filling after the user's weight has been unloaded and the air sucked through the gaps among the igloos with consequent air circulation during walking. Figure 2 also shows upper surface 3 of the sole as well as surface 11 to which the vamp is glued and groove 13 in which the sewing is made. Turning now to Figures 4 and 5, in which the construction components corresponding to those already described are designated by the same numerals as those used in Figures 2 and 3 with the addition of a prime, the operation is quite similar to that already described above. Even if such a second embodiment bears features found in the first embodiment, it provides igloo-shaped air chambers having a hemispheric upper portion which is wholly located under upper surface 3' of the sole. In this case also the deflection of the igloos by the user's weight causes air to be blown into the shoe and top holes 1' to be then occluded by protrusions 6' so that residual air in cavity 9' is caused to provide the already described resilient shock-resistant action. The protrusions 6' have a different form from those of the preceding embodiment as they have a tapered, roundish point 16 at the top of an offset 15. Such an offset aims at occluding top holes 1' during the deflection caused by the user's weight on walking in order to produce the already described shock-resistant effect. In the second embodiment roundish point 16 has a diameter which is smaller than that of top hole 1' and such a height as to slightly project from upper surface 3' of the sole when the igloo is deflected and offset 15 occludes hole 1'. In this case roundish point 16 projecting from surface 3' softly strains the lower surface of cleaning sole C of the shoe producing a massaging effect which considerably improves blood circulation of the foot. A third embodiment of the invention shown in Figures 6 and 7 has essentially the same features as the preceding embodiments but is simplified as it does not provide any protrusions capable of occluding the top hole during walking. In this case the shock-resistant function is only accomplished by the resilient deformation of the igloos that make up the sole. It should be appreciated that igloos having different volumes and/or heights may be advantageously provided in order to satisfy the most diverse technical and/or aesthetic requirements. The lower portion of the air chambers forming the tread can provide a constant undulating movement in addition to the pleasant sensation of softness given by the flexibility of the igloos. Such movement gives rise to a good cleaning action against dirt which often enters the grooves in the tread. In case the user stops walking, still another advantage of the invention is that the air chambers formed by the igloos perform an insulating action keeping the inner temperature of the shoe close to that of the body. The sole according to the invention described can be produced in just one moulding step by using resilient material of different kinds capable of being deformed and recovering their original shape immediately after the deformation. Said materials are preferably resistant to abrasions, ultraviolet rays and low temperatures. Of course, the sole of the invention can be applied to any type of shoe.

Claims: A shoe-sole comprising a plurality of resilient hollow air chambers extending through the whole thickness of the sole, said air chambers being dome-shaped with a central hole (1, 1') at the top, have an upper hemispherically shaped portion (2) with a top plane suitable to support a fixed perforated insole (B), and a lower portion (5) forming the tread (10, 10') and extending below support members (4, 4') connecting the plurality of air chambers, said air chambers being capable of deflecting during walking by blowing the air contained therein into the shoe (A) through said top central holes (1, 1') and through holes of said fixed perforated insole (B); the lower surface of the fixed perforated insole (B) resting on the air chambers so as to form a valve which causes, during the expulsion of the air contained in the air chambers, the air to push the edge of the top central holes (1, 1') against the perforated insole (B) preventing the air from escaping sideways and forcing the air to reach the inside of the shoe thereby establishing an air circulation and supplying a soft surface to a user's foot. The sole according to claim 1 comprising a conical protrusion (6, 6') projecting from the inner base of each air chamber towards the respective top central hole (1, 1') so that when the air chambers are deflected by the user's weight, each protrusion (6, 6') will obstruct the corresponding top central hole (1, 1') before all of the air contained in the air chamber escapes, thereby performing a shock resistant action. The sole according to claim 2, wherein said protrusions (6') have a tapered, roundish point (16) at the top of an offset (15), said offset (15) having the function of occluding the top central hole (1') of said air chambers during the deflection caused by the user's weight on walking before all of the air contained in the air chamber escapes. The sole according to any of the preceding claims, wherein the lower portion of the air chambers forming the tread (10, 10') has a flexibility providing a constant undulating movement of said portion, said movement causing a cleaning action against dirt picked up by the grooves of the tread spaced between the lower portions. The sole according to any of the preceding claims, wherein the bottom of the lower portion of each air chamber forming the tread (10, 10') has a central portion (7, 7') shaped as a suction cup. The sole according to any of claims 1 to 4, wherein the bottom of the lower portion of each air chamber forming the tread (10, 10') has a central portion (7) having notches capable of an antislip action. The sole according to any of the preceding claims comprising a peripheral rib (14) for anchoring the sole to the vamp of a shoe (A) by conventional gluing and, if necessary, sewing.

Inventors: SQUADRONI ONIFARES ELPIDIO, SQUADRONI, ONIFARES ELPIDIO
Applicants: CALZATURIFICIO VALLEVERDE S P, CALZATURIFICIO VALLEVERDE S.P.A.
Application year: 1998
Main classification: A43B13
IPC codes: A43B13, A43B7