A VENTILATING INSOLE FOR SHOES

Abstract: A ventilating insole for footwear includes a resilient, air-permeable sheet (1) which is intended to support the wearer's foot. The sheet (1) includes an essentially impervious casing (2). The casing has an opening (3) in the toe-region of the insole and a rear opening (4) in the rear part on the insole. A check valve (5) is connected to the rear opening (4) and functions to allow air to pass through in a direction from the interior of the insole (8).

Description: A VENTILATING INSOLE FOR SHOES The present invention relates to a ventilated insole for footwear, of the kind defined in the preamble of Claim 1. Examples of such insoles are apparent from DE-A-2 109 422, GB-A-2 189 679, US-A-2, 545, 062 , US-A-2 , 741 , 038 and US-A- 3,142,912. It is well known that the insides of footwear, such as the inside of a low shoe, a boot, etc., becomes quickly warm and moist, particularly in the case of a rubber Wellington boot. With this in mind, efforts have long been made to design footwear that will enable ambient air to circulate inside the footwear, particularly in the toe of the footwear. A basic feature of these earlier designs, or constructions, resides in an insole that includes an air pumping passageway extending from the toe to the heel part of the insole, and valve means which are actuated by the wearer's foot to establish an air flow through the insole as the wearer moves his/her feet. US-A-3, 142,912 teaches an insole that includes an air- permeable, elastically deformable and porous sheet enclosed in an impervious casing. A through-penetrating opening is provided in the casing on the upper side of the insole, in the region of the wearer's heel. The casing also includes openings in the toe region of the insole. In this case, the heel-plantar surface, or heel pad, of the wearer is intended to coact with the rear openings in the insole in a manner to drive ventilation air forwardly through the insole and towards the toe region thereof sole as the wearer moves forwards . This solution, however, has several drawbacks. For instance, the wearer's foot is sensitive to openings in the casing surface. Furthermore, the resistance of the foam sheet to air flow must be a low, so as to enable air to be transported along essentially the full length of the insole. These various requirements are not mutually compatible, since an insole that has a high bearing resistance will have poor air conductivity, and vice versa. Furthermore, the heel valve means of the known insole function unsatisfactorily when, for instance, the user is wearing a thick and porous sock or stocking and when the heel plantar is not lifted away from the insole as the wearer walks. Accordingly, it is an object of the present invention to provide a ventilated insole with which these drawbacks are avoided, either entirely or partially. This object is achieved with an insole according to the following Claim 1. Thus, a fundamental feature of the invention is that the insole is comprised of a sheet of uniform thickness that covers the inner, bottom surface of an article of footwear and which is provided with an impervious casing. The sheet is elastically deformable and permeable to air and has uniform bearing capacity across the whole of its main surface. The insole may thus be made of an open-cell foamed plastic sheet for instance. The casing has an opening in the toe-part of the insole and an opening in the rear part thereof. By "rear part" is meant the region of the wearer's heel and foot arch. The rear opening includes a check valve which is adapted to release air from the insole. Air is thus sucked in through the toe-part of the insole and expelled through the rear opening in the casing. When the heel region of the insole is subjected to the rapidly fluctuating and powerful loads exerted by the wearer's heel as he/she steps forwards, the air displaced from the heel region of the insole will depart through the check valve in the rear opening, since this flow path presents a much lower resistance to flow than that presented by the part of the air permeable sheet extending to the front opening. When the wearer's heel releases the load on the insole, the check valve will close. Air can, however, still be sucked readily from the toe-area of the footwear, through the front opening and back to the heel region of the insole, since the rate of air flow is then much lower and is generated by the restoration of the resilient heel part of the sheet to its natural shape, wherewith the air resistance presented by the sheet is much lower than the resistance to the high air rates occurring when the heel part is subjected to load. The rear opening may be located on the furthest rearward part of the insole, or in the position of the foot arch of the insole. In this latter case, the air expelled through the check valve may possibly flow upwards and out from the footwear. When the inner sole is to be used in boots and like footwear, it may be preferred to connect the rear opening to a point in the vicinity of the upper edge of the boot opening or to a point externally of this upper edge, through the medium of a hose or like conduit. In this case, the check valve may be mounted in the hose or like conduit. The check valve may be of simple construction, such as simply a flattened end-part of a resilient hose that communicates with the rear opening, for example. Alternatively, the check valve may be comprised of a resilient lip that lies across the rear opening or outlet, particularly when the check valve is located in the heel region of the insole, for instance on the upper side thereof. The invention will now be described with reference to exemplifying embodiments thereof and also with reference to the accompanying drawings , in which Fig. 1 shows an insole from above; Fig. 2 is a schematic sectional view taken on the line II-II in Fig. 1; and Fig. 3 is a vertical, longitudinal section view of a boot, or bootie, provided with an inventive insole. Fig. 1 shows from above a ventilated insole 8 constructed in accordance with the invention. The insole 8 is essentially flat and of uniform thickness and has a uniform bearing capacity over the whole of the area loaded by the foot of the wearer. The insole 8 is comprised of a sheet of elastic, deformable, air-permeable material, for instance a relatively rigid open-cell foamed plastic sheet of uniform thickness. The sheet 1 is covered with an essentially impervious casing 2 over essentially the whole of its surface, said casing 2 having an opening 3 at the toe-part of the insole 8 and an opening 4 at the rear region of said insole. By "rear region" is meant the region covered by the heel and foot arch of the insole 8. A check valve 5 is connected to the opening 4 , to permit air to escape from the interior of the insole 8. The inventive insole 8 functions in the following manner. When the wearer steps forwards and his/her heel exerts load on the heel-part of the insole 8, the plate 1 will be compressed in this region and displace air present therein towards the toe-part of the insole. The heel-part of the insole is loaded quickly and powerfully, and hence the plate 1 will present a relatively high air resistance, which causes the air displaced from the heel-region of the insole to depart through the nearest opening in the casing 2, namely through the rear opening 4 and through the check valve 5 connected thereto. When the wearer then lifts his/her foot, the resilient sheet 1 will return elastically to its initial shape and remain in this state until the next heel-loading occasion. During this time period, air is sucked from the foot-part of the footwear, through the toe-opening 3 in the casing 2 and towards the heel-part of the insole 8. This inflow of air can take place at a relatively low air resistance, due to the relatively low flow rate that is generated as the sheet 1 returns to its initial shape or state in the heel-part of the insole. The rear opening 4 may conveniently be placed on the. inner long-edge of the insole 8 in the region of the foot arch thereof. Alternatively, the rear opening can be placed in any other desired position, for instance at the illustrated position 7 furthest back on the insole 8. When the inventive insole 8 is used with a low shoe, i.e. a shoe that has a small extension from the sole to the edge of its upper opening, air is able to flow out from the footwear through the outlet opening 4 without needing to take any particular measures to this end. On the other hand, when the footwear is a boot that has a relatively long leg, a hose 6 may be conveniently connected to the opening 4 and caused to open out in the vicinity of the upper rim of the boot. By causing air to be transported from the toe-end of the insole to the rear part thereof in accordance with the invention, no check valve is required for the flow of air into the actual pump chamber formed by the heel-part of the insole 8. Furthermore, the outlet opening 4 may be fitted with a check valve 5 that closes in a direction towards the interior of the insole 8. Particularly simple check valve constructions may be used to this end. As shown in Fig. 2, the casing 2 around the sheet 1 may be formed as a resiliently pivotal tongue 51 that covers the opening 4. Alternative similar check valves having on the outside a tongue that covers the opening 4 are available to the skilled person and can be readily produced, particularly in the foot arch region of the insole 8, where the wearer's foot does not come into contact with the upper surface of the insole. Alternatively, the check valve 5 may be comprised of a resilient hose-stump whose inner end connects through the opening 4 and whose outer end is flattened to provide a check valve function. The hose may, of course, also be made longer (c.f. the hose 6 in Fig. 3). Although the insole may be permanently fitted in the footwear concerned, it is preferably inserted loosely therein. The sheet 1 may also include a deodorant.

Claims: CLAIMS 1. A ventilating insole for footwear, wherein the insole comprises a resilient, air-permeable sheet (1) which is intended to support the wearer's foot and which includes an essentially impervious casing (2), and wherein said casing has an opening (3) in the toe-region of the insole and a rear opening (4) in the rear part of said insole (8), characterized by a check valve (5) which is connected to the rear opening (4) and which functions to allow air to flow out in a direction from the interior of the insole (8). 2. An insole according to Claim 1 , characterized in that the rear opening (4) is provided in the foot arch region of the insole (8) . 3. An insole according to Claim 1 or Claim 2, characterized in that the insole covers essentially the entire upwardly facing, exposed area of the sole of the footwear. 4. An insole according to any one of Claims 1 to 3, characterized in that the insole is a separate unit that can be placed in and removed from footwear. 5. An insole according to any one of Claims 1 to 4, characterized by a hose (6) which connects the rear casing opening (4) to a point externally of the footwear, or to a point in the proximity of the ankle opening of said footwear. 6. An insole according to any one of Claims 1 to 5, characterized in that the sheet ( 1 ) is porous and has a uniform bearing capacity across its planar surface. 7. An insole according to Claim 6, characterized in that the sheet (1) is a foamed plastic sheet or a fibre sheet. 8. An insole according to Claim 6 , characterized in that the sheet ( 1 ) is comprised of an open-cell foamed plastic material.

Inventors: NEIDHARDT DIETER, NEIDHARDT, DIETER
Applicants: NEIDHARDT DIETER, NEIDHARDT, DIETER
Application year: 1997
Main classification: A43B7
IPC codes: A43B17