Footwear with enhanced temperature control

[0002] The invention relates to footwear, and particularly to athletic footwear having features which provide improved comfort to the wearer, particularly from a standpoint of modulating or controlling the temperature of the foot. The invention is primarily directed to a shoe having features to keep the foot cool and dry. Certain aspects of the invention could also be utilized in footwear designed to keep the foot warm.

[0003] Discussion of Background

[0004] The footwear industry, particularly the athletic footwear industry, has seen numerous design features introduced in order to enhance the comfort and/or performance of the wearer. Often such modifications relate to enhancing the manner in which the shoe supports the foot, such that the shoe can, for example, better absorb impacts or allow the wearer to more comfortably exert a large amount of force while reducing the possibility of injury. These designs modifications demonstrate, that comfort and performance are often interdependent. An athlete who can rely upon his or her footwear to perform without injury or discomfort can better train and perform up to their potential.

[0005] One aspect of footwear design which often receives less attention relates to foot temperature and the ability of the footwear to prevent excessive heat or, in some instances, to retain heat. For many athletic activities, such as running or tennis, the wearer must perform in hot temperatures and upon surfaces (e.g., asphalt) which can be even hotter than the ambient temperature. In these conditions, it is important for the shoe to keep the foot as cool and dry as possible. Similarly, if the athlete is to perform in cold conditions, the footwear should be able to retain heat to optimize the wearer's performance and prevent injury.

[0006] Whether the athlete is an occasional athlete or a professional, the ability of the footwear to modulate temperature can have both comfort and performance effects. Obviously, whenever there is foot discomfort, the physical activity is less enjoyable. In addition, such discomfort can psychologically and physiologically detract from the performance of the wearer. Generally, with athletic footwear utilized, e.g., in running or tennis, it is desirable to prevent overheating of the foot. Excessive foot temperature can lead to excessive perspiration and premature fatigue (mentally and physically). Further, excessive perspiration can also detract from the wearer's ability to react quickly, take a quick step, or change directions, since the foot is held less firmly within the shoe.

[0007] Under certain conditions, it can also be desirable to retain heat, e.g., where the athletic activity is to be performed in a cold climate. The retention of heat can be important in providing comfort to the wearer, preventing injury or frostbite, and providing better circulation. Obviously, temperature modulation is very important in enhancing the wearer's comfort and performance.

[0008] A number of footwear designs have attempted to provide desirable temperature modulation. For example, U.S. Pat. No. 4,055,699 to Hsiung discloses the use of a four layer insole to enhance the insulating characteristics of the shoe, with the bottom layer formed of aluminized Mylar. However, the Hsiung arrangement is suitable for cold climates, but does not assist in modulating foot temperature in hot conditions. Moreover, the use of Mylar at the bottom of the insole can be problematic in that the Mylar can deteriorate or degrade with use. Further, if the Mylar is utilized in hot conditions as a bottom layer, there is an increased possibility of degradation and/or delamination of the Mylar.

[0009] Particularly from a standpoint of preventing excessive heating of the foot, the primary difficultly resides in the ability to modulate heat at the underside of the foot. However, it can be difficult to incorporate successful temperature modulating features without detracting from cushioning and support functions—which are often the primary focus of athletic shoe designs in the region beneath the foot. Thus, it can be difficult to provide a design which will not interfere with the cushioning/support functions of the shoe while also providing a durable design which can keep the foot cool and dry.

[0010] It is an object of the invention to provide a shoe having enhanced capabilities in controlling or modulating the temperature of the wearer's foot. Although the primary focus of the invention resides in the ability to prevent overheating of the foot, and to keep the foot cool and dry, certain aspects of the invention could also be advantageously utilized in retaining heat within the shoe. In a particularly preferred form of the invention a multilayer assembly, comprised of a heat resistant film disposed between two layers of strobel material, is disposed between the midsole and the insole of the shoe. The heat resistant film can be, for example, a metalized Mylar film. Such a film has a reflective surface and a non-reflective surface. Where it is desired to prevent overheating of the foot, the reflective surface of the film faces toward the midsole and acts as a barrier to reduce or inhibit the transfer of heat from hot surfaces (such as asphalt) to the foot. If desired, this arrangement could also be utilized in footwear designed to retain foot heat, in which case the reflective surface of the film would be disposed to face toward the insole. As noted above, the primary focus of the invention is upon footwear designs which can reduce overheating of the foot, to thereby keep the foot cool and dry.

[0011] With the heat resistant film disposed in the strobel material, the durability of the film is enhanced, since there is little risk of delamination, and the Mylar film is protected by the surrounding strobel material. Further, the positioning of the multilayer strobel and Mylar film layer beneath the insole is additionally advantageous in accordance with the invention, since a ventilation system is incorporated in the insole design. Thus, the multilayer strobel/Mylar assembly not only reduces the heat transfer from a hot surface to the foot, but also, the performance of the ventilation system is enhanced since the air in the ventilation system is also protected from the heat of the hot surface. Other advantageous aspects of the invention are disclosed in further detail hereinafter.

[0012] A more complete understanding of the invention the advantages associated with the invention will become further apparent from the detailed description which follows, particularly when considered in conjunction with the drawings in which:

[0013] FIG. 1 is a side exploded view of a shoe according to the invention.

[0014] FIG. 2 is a top view of a right foot insole according to the invention;

[0015] FIG. 3 is a bottom view of a left foot insole of the invention;

[0016] FIG. 4 is a cross-sectional view along lines IV—IV of FIG. 3;

[0017] FIG. 5 is a cross-sectional view along line V—V of FIG. 3;

[0018] FIG. 6 is a cross-sectional view along line VI—VI of FIG. 3;

[0019] FIG. 7 is a side view of the medial side of the insole of FIG. 3;

[0020] FIG. 8 is a side view of the lateral side of the insole of FIG. 3; and

[0021] FIG. 9 is a cross-sectional view along line IX—IX of FIG. 3.

[0022] Referring now to the drawings, FIG. 1 is a side exploded view of a shoe in accordance with the present invention. The shoe is particularly advantageous from a standpoint of dissipating heat from the shoe and in preventing heat from hot surfaces, as can be encountered in tennis or running, from overheating the foot. The shoe includes a sole/midsole assembly represented at 10, above which an advantageous multilayer assembly 12 is provided. The sole/midsole assembly 10 can have various forms depending upon the shoe's usage and/or the wearer's preferences. Thus, the sole/midsole assembly 10 can be of various designs which provide the cushioning and support functions the athlete desires for a particular sporting activity. In accordance with the invention, the multilayer assembly 12 preferably includes a heat resistant layer or film 12b. This heat resistant layer serves to inhibit the transfer of heat from, e.g., hot asphalt surfaces, to the foot. In a presently preferred form, the layer 12bis a polymeric film which has a reflective or shiny surface and a non-reflective or non-shiny surface. For example, the heat resistant layer can be a metalized Mylar material (polyethylene terepthalate), which is sandwiched between two layers 12a, 12cof material such as strobel material or strobel board. Such Mylar materials are also known as aluminized Mylar or chrome Mylar. Although the material of layers 12aand 12cis often referred to as strobel “board,” it typically is a pliable material, and can include a non-woven or woven fiber material.

[0023] As shown in FIG. 1, the Mylar 12bis sandwiched between a first layer 12aof strobel material and a second layer 12cof strobel material. This strobel sandwich is strobel stitched to the upper 14, with the strobel stitching represented at 12din FIG. 1. As noted above, the Mylar material is preferably a metalized Mylar, which typically includes a reflective or “shiny” side and a non-reflective or “non-shiny” side. Where it is desirable to prevent excessive heat to the foot, the Mylar sheet is disposed such that the shiny or reflective side faces down. With this arrangement, the Mylar film acts as a barrier to reduce or inhibit the transfer of heat from a hot surface, such as a tennis court of asphalt surface, to the foot. If, however, it is desired to retain heat, the layer 12bis disposed such that the shiny or reflective surface faces upwardly, toward the insole.

[0024] In accordance with a particularly preferred form of the invention, the shoe prevents excessive heating of the foot, and the shiny or reflective surface of the layer 12bfaces down, toward the midsole, while the non-shiny or non-reflective surface faces up, toward the insole. Since the Mylar film is extremely thin, it will not detract from the performance of the shoe from a cushioning/support standpoint. In fact, the Mylar film can be quite thin, such that it is barely visible between the layers of strobel material when the multilayer assembly 12 is viewed in cross-section. The heat resistant film adheres well to fabrics such as strobel board. Further, since the heat resistant film is sandwiched within the strobel material, the durability of the Mylar film essentially becomes the same as that of the strobel material. Thus, problems associated with delamination or deterioration of the Mylar film are avoided with the arrangement of the invention. As noted earlier, if the shoe is to be utilized under conditions in which it is desired to retain foot heat, the same multilayer assembly 12 can be used, with the heat resistant film disposed such that the reflective or shiny side faces upwardly toward the upper.

[0025] In the arrangement of FIG. 1, additional venting features are provided to further assist in modulating the foot temperature under potentially hot conditions. In combination with the use of a heat resistant film, such as metalized Mylar having the shiny or reflective side down, the venting features further assist in keeping the foot cool and dry. The venting features include a series of openings 16, 17 disposed in the upper to allow the foot to breathe through the openings. If desired, these openings can be covered (preferably from the interior of the shoe) utilizing a mesh/screen material, such as a fine wire or nylon mesh material. This mesh material allows the foot to breathe through the openings while also providing protection to the foot and preventing debris from entering into the shoe through the openings. The mesh material can also assist in maintaining the structural integrity of the upper despite the presence of the openings. The openings extending through the upper can include elongated slot openings as shown at 16 and/or a plurality of circular openings or perforations as shown at 17. Of course, openings of other sizes and shapes could also be utilized. These openings provide ventilation for the interior of the shoe through the upper of the shoe and to locations in the upper portion of the foot, i.e., above the multilayer assembly and above the shoe insole.

[0026] In addition to the vent openings 16, 17, a vent opening 20 is provided for ventilation of the shoe in the region above the multilayer assembly 12 and below the insole. Details of an insole which can advantageously cooperate with vent openings 20 are discussed hereinafter. Preferably, vent openings 20 are provided on both the lateral and the medial sides of the shoe. In the arrangement shown in FIG. 1, when the shoe is assembled, a portion of the upper is received within the midsole, such that an aperture 20aextending through the midsole aligns with the aperture 20bextending through the upper, to form the vent opening 20. As with the openings or apertures 16, 17 discussed above, the vent opening 20 can also be covered with a mesh/screen material 20c.

[0027] As noted above, the vent openings 20 communicate with the interior of the shoe at a location between the multilayer assembly 12 and the insole. Such an arrangement can be advantageous in a number of respects. First, as noted above, the multilayer assembly 12 reduces the amount of heat which can pass from a hot surface to the wearer's foot. Second, heat can be removed from the wearer's foot utilizing the vent openings 20, as well as vent openings 16, 17. Further, the ventilation through the opening 20 (and utilizing the ventilation system provided in the insole described hereinafter) is also more effective in view of the fact that the heat resistant film of the multilayer assembly 12 is disposed beneath the insole assembly so that heat transfer from a hot surface to air within the ventilation system is also inhibited. Thus, the multilayer assembly 12 can assist in reducing heat transfer from a hot surface to the foot, and also in reducing heat transfer from the hot surface to the air of the ventilation system to thereby enhance the effectiveness of the ventilation system.

[0028] FIGS. 2 and 3 are, respectively, top and bottom views of an insole in accordance with the present invention. (FIG. 2 corresponds to a top view of a right foot insole, while FIG. 3 corresponds to a bottom view of a left insole.) The insole (sometimes also referred to as a sock liner) is removable in a presently preferred form of the invention. Alternately, the insole can be fastened within the shoe by various expedients or combinations of expedients, including adhesive bonding or stitching. The insole 30 is disposed above the multilayer assembly 12 and inside of the upper 14.

[0029] As shown in FIGS. 2 and 3, the insole 30 includes a bottom support 32, which supports the wearer's foot. This bottom support 32 includes a top surface 32a, a bottom surface 32b, and a plurality of apertures 34 extending through the insole from the top surface to the bottom surface. As shown in FIG. 3, the insole includes a heel region 36, a central region 38, and a forefoot region 40. The apertures 34 are preferably, but need not be, provided in each of these regions. In the central region 38, a plurality of channels are additionally formed in the bottom surface 32bof the bottom support 32 of the insole. These channels 42 assist in the dissipation of air/heat through the apertures 34 and to the exterior of the shoe, since the channels provide communication paths or passageways from the apertures 34 to the vent openings 20. In accordance with the present invention, it is preferable to provide the channels 42 in the central region 38 of the insole, since the central region is typically that which requires the most heat dissipation. Moreover, if a contoured/channeling structure is provided in the heel or forefoot regions of the foot, such channels could cause discomfort or otherwise interfere with the cushioning/support features of the shoe provided by the sole/midsole assembly. The channels 42 can extend in the lengthwise direction of the shoe, and can also extend transverse thereto as shown. As shown in FIG. 3, a large channel 42aextends across the bottom surface 32bof the insole in the central region 38. This large channel 42acommunicates with the vent openings 20 which extend through the shoe (e.g., via openings 20a, 20bprovided in the midsole and upper) as discussed earlier. Thus, the vent openings 20 provided in the medial and lateral sides of the shoe communicate with the channel 42a. The channel 42a, in turn, communicates with the remaining channels 42 on the bottom surface 32bof the insole, so that air and heat can pass along the bottom surface of the insole and through the apertures 34 to cool the bottom of the foot. The circulation of air utilizing the ventilation system is further enhanced as the wearer presses against and releases force from the insole, as the insole and the air passageways are compressed and released during movement of the wearer.

[0030] FIGS. 4-6 are cross-sectional views of the insole 30, respectively taken along lines IV—IV, V—V, and VI—VI of FIG. 3. By way of further illustration, FIG. 7 is a side view of the insole of FIGS. 2 and 3 on the medial side of the insole. FIG. 8 is a lateral side view of the insole of FIGS. 2 and 3. FIG. 9 is a cross-sectional view of the insole along section IX—IX of FIG. 3.

[0031] As shown in FIGS. 4-6, the insole 30 can include a foamable material 50, such as a foamable resin material, with a fabric 52, such as a nylon or polyester lining, disposed over the foamable resin 50. Typically, the lining 52 and foamable resin material 50 are associated with each other and thereafter are compression molded to the desired insole shape. The perforations 34 through the insole 30 can be molded or, if desired, can be formed by die cutting the insole after compression molding. As shown in FIGS. 3 and 5, a raised boss 54 can be provided within the enlarged channel region 42a. This raised boss 54 can provide a location to display a logo, and also can provide a flow diverter, so that air does not simply pass from the lateral vent opening to the medial vent opening 20 without aerating the remainder of the insole. In addition, this boss 54 can ensure adequate support in the central region 38 of the shoe, particularly in the region in which the enlarged channel is provided.

[0032] As shown in FIGS. 5 and 6, the insole 30 will preferably include an upwardly extending portion 56 on the medial side of the shoe and an upwardly extending portion 58 on the lateral side of the shoe. Channels and apertures can also be provided in the upwardly extending portions 56, 58 to further enhance the ability of the shoe to keep the foot cool and dry. In the embodiment shown, apertures 60 (FIGS. 3 and 8) extend through upwardly extending portion 58 the insole on the lateral side of the shoe, while the upwardly extending portion 56 on the medial side of the insole includes both apertures 62 and channels 64 (FIGS. 3 and 7). As shown in FIGS. 3 and 7, the channels 64 can include intersecting channels, with channels 64aextending upwardly and channels 64bextending in the lengthwise direction of the foot. The lowermost channel 64bis disposed adjacent to the enlarged channel 42aof the bottom surface of the insole, such that the medial vent opening 20 of the shoe can communicate with both the channels disposed on the bottom surface 32bof the insole as well as the channels 64 of the upwardly extending medial portion 56.

[0033] As should be apparent from the foregoing, the present invention is advantageous in a number of respects. By providing a heat resistant layer, particularly a metalized Mylar (polyethylene terepthalate), disposed between two pieces of strobel material, an effective and durable multilayer assembly is provided which can modulate the temperature of the foot. When utilized in the preferred arrangement of the present invention to keep the foot cool and dry, the multilayer assembly is effective in not only inhibiting heat from hot surfaces from transferring to the foot, but also in inhibiting the transfer of heat to the ventilation system of the invention to prevent deterioration of the performance of the ventilation system. As is also apparent, the present invention provides an advantageous ventilation system which provides for circulation of air beneath the foot, without detracting from the support/cushioning functions of the remainder of the shoe. The ventilation system is particularly advantageous in providing for flow channels or passageways in the central region of the foot at the bottom of the insole, to provide passageways for air and heat which can flow through apertures extending through the insole.

[0034] Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise and as specifically described herein.