Abstract:
A sole structure for an athletic shoe includes a heel region and a forefoot region, a midsole of a soft elastic material including a midsole heel portion at the heel region, and an outsole of a harder material including an outsole heel portion at the heel region and an outsole forefoot portion that extends from the outsole heel portion to the forefoot region. The midsole heel portion has wavy corrugations on a lower surface thereof and a smooth plane on an upper surface thereof. The outsole heel portion includes a corrugated wavy plate with corrugations through its thickness, which are in phase with the wavy corrugations on the lower surface of the midsole heel portion.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Divisional of U.S. application Ser. No. 09/832,056, filed Apr. 10, 2001, now U.S. Pat. No. 6,557,270, issued May 6, 2003. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to a sole structure for an athletic shoe, especially for a spiked shoe such as a soccer shoe, a baseball shoe, a golf shoe, or the like. 
     A prior art sole structure of an athletic shoe for use in various sports is shown in Japanese patent application laying-open publication No. 11-203. This sole structure includes an upper midsole and a lower midsole both of which are generally formed of soft elastic materials, a corrugated sheet interposed between the upper and lower midsoles, and an outsole disposed under the lower surface of the lower midsole and directly contacting the ground. 
     In such a shoe, due to the corrugated sheet interposed in the heel portion of the midsole, a resistant force tends to occur that restrains the heel portion of the midsole from deforming transversely at the time of contacting the ground, which prevents the heel region of the shoe from slanting sideways and thus, running stability is secured. 
     The prior art sole structure, however, is comprised of four layers including an upper midsole, a lower midsole, a corrugated sheet, and an outsole, thereby making the weight of the whole sole structure heavier and making the assembly process rather complicated, and an extra cost of a mold becomes necessary. 
     An object of the present invention is to provide a sole structure for an athletic shoe that secures running stability, decreases weight, simplifies a manufacturing process, and reduces cost. Another object of the present invention is to control flexibility or bendability of an outsole or an outsole body of a shoe structure. A still another object of the current invention is to regulate an upper force applied to an outsole or an outsole body from the ground. 
     SUMMARY OF THE INVENTION 
     In one embodiment, the sole structure includes a midsole and an outsole located under the midsole and formed of a harder material than the midsole. The midsole is disposed at least at a heel region of a shoe and the midsole heel portion is formed with corrugation at a lower surface thereof at least either on a medial or on a lateral side. The outsole includes an outsole heel portion having corrugation corresponding to the corrugation of the midsole heel portion and an outsole forefoot portion extending from or formed integrally with the outsole heel portion. 
     Owing to the corrugation or wavy configuration formed at each contact surface between the outsole and the midsole, a resistant force occurs that restrains the midsole heel portion from deforming laterally at the time of contacting the ground, thereby preventing the heel region of the shoe from slanting sideways and securing running stability. Moreover, a two-layer-sole structure with the midsole and the outsole reduces the number of components of the sole structure, decreases the weight of the whole sole structure, simplifies a manufacturing process, and reduces a cost of molds. Furthermore, since the sole structure can be made thinner than a prior art structure, bendability or flexibility of the sole is improved. 
     The outsole forefoot and heel portions may be formed of the same material or a different material. The midsole may be extended from the heel region to the forefoot region of the shoe. In this case, cushioning properties are ensured along the whole length of the shoe. The wavy configuration of the outsole heel portion may be formed consecutively and laterally between a medial side and a lateral side of the outsole heel portion. In this case, lateral slanting of the heel region of the shoe is more securely prevented. The outsole forefoot portion may also be formed with corrugation. Thus, lateral slanting of the forefoot region of the shoe as well can be prevented. 
     In a second embodiment, a plurality of plastic or metallic cleats or spikes are provided under the outsole. The sole structure of this embodiment may be applied to a spiked shoe, such as a soccer shoe, a baseball shoe, a golf shoe, a track shoe, or the like. Preferably, the cleats are adapted to control bendability or flexibility of the outsole and to control an upper force applied to the outsole from the ground. The cleats may be located at a crest or a trough of the corrugation of the outsole. Here, the term “crest” and “trough” are interpreted in FIG. 7, which is a side enlarged view of the sole structure. As shown in FIG. 7, a convex portion on the uppers side away from the ground is a crest whereas a convex portion on the ground side is a trough. 
     In this case, flexibility of the outsole is prevented from being hindered. Specifically, when the cleats are provided at a trough of the corrugation of the outsole, the upper force applied to the cleats from the ground is transmitted to the adjacent crests disposed on both sides of the trough, and thus, the upper force is dispersed and relieved. 
     The cleats may be disposed between a crest and the adjacent crest or a trough and the adjacent trough of the corrugation of the outsole. In this case, the upper force applied to the cleats from the ground is effectively relieved by the corrugation of the outsole and flexibility of the outsole is restrained. For example, when the cleats are located between a trough and the adjacent trough of the corrugation of the outsole, the upper force from the ground is dispersed and absorbed by the both troughs. 
     The heel portion of the midsole may have a corrugated sheet or wavy plate therein. In this case, lateral leaning of the heel region of the shoe is further securely prevented. 
     In a third embodiment, the sole structure includes a midsole body, an outsole body disposed under the midsole body and formed of a harder material than the midsole body, a lower midsole disposed under the heel portion of the outsole body, and an outsole heel portion attached under the lower midsole. The midsole body and the outsole body extend from the heel region to the forefoot region of the shoe. The outsole body has corrugation at least at the heel portion thereof. 
     In this embodiment, the corrugation formed at the heel portion causes a resistant force that prevents the heel portion of the midsole body from deforming laterally at the time of contacting the ground, thereby preventing the heel region of the shoe from slanting sideways and thus, securing a running stability. Moreover, in this case, the forefoot region of the shoe has a double-layer-sole structure with the midsole body and the outsole body, which reduces the number of shoe components, decreases the weight of the shoe, simplifies a manufacturing process, and reduces a manufacturing cost. Furthermore, since the sole structure can be made thinner as compared with the prior art structure, bendability or flexibility of the forefoot region of the shoe is advanced. The outsole body may have corrugation at a forefoot portion thereof. In this case, lateral leaning of the forefoot region of the shoe can also be prevented. 
     In a fourth embodiment, a plurality of cleats are provided under the outsole body. The sole structure of this embodiment may be applied to a spiked shoe, such as a soccer shoe, a baseball shoe, a golf shoe, a track shoe, or the like. The cleats are preferably adapted to control bendability or flexibility of the outsole body and to control an upper force applied to the outsole body from the ground. The cleats may be located at a crest or a trough of the corrugation of the outsole body. In this case, bendability or flexibility of the outsole body can be restrained from being hindered. Specifically, when the cleats are provided at a trough of the corrugation of the outsole body, the upper force applied to the cleats from the ground is dispersed and relieved by the adjacent crests. Alternatively, the cleats may be disposed between the adjacent crests or troughs of the corrugation of the outsole body. In this case, the upper force applied to the cleats from the ground is effectively relieved by the corrugation of the outsole body and the flexibility of the outsole is restrained. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a more complete understanding of the invention, reference should be made to the embodiments illustrated in greater detail in the accompanying drawings and described below by way of examples of the invention. In the drawings, which are not to scale: 
     FIG. 1 is a side view of a soccer shoe employing a sole structure of one embodiment of the present invention. 
     FIG. 2A is a bottom view of the sole structure of FIG.  1 . 
     FIG. 2B is a medial side view of FIG.  2 A. 
     FIG. 2C is a lateral side view of FIG.  2 A. 
     FIG. 3 is a side view of a baseball shoe employing a sole structure of a second embodiment of the present invention. 
     FIG. 4A is a bottom view of the sole structure of FIG.  3 . 
     FIG. 4B is a medial side view of FIG.  4 A. 
     FIG. 4C is a lateral side view of FIG.  4 A. 
     FIG. 5 is a side view of a golf shoe employing a sole structure of a third embodiment of the present invention. 
     FIG. 6A is a bottom view of the sole structure of FIG.  5 . 
     FIG. 6B is a medial side view of FIG.  6 A. 
     FIG. 6C is a lateral side view of FIG.  6 A. 
     FIG. 7 is a side enlarged view illustrating corrugated portions of the outsole and the midsole. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Turning now to the drawings, FIG. 1 shows a soccer shoe of one embodiment of the present invention. As shown in FIG. 1, a soccer shoe  1  has a sole structure that is formed of an outsole  3  provided under an upper  2  and extending from a heel region to a forefoot region of the shoe  1  and directly contacting the ground, and a midsole  4  provided inside the outsole  3  and under the upper  2  and extending from the heel region to a midfoot region of the shoe  1 . On the lower surface of the outsole  3  a plurality of cleats  5  are provided. 
     As shown in FIGS. 2B and 2C, the outsole  3  includes upraised side portions  3   b  and  3   c  extending upwardly (or in the left and right directions of FIGS. 2B and 2C) from a base portion  3   a  on the medial and lateral sides. An outsole corrugated portion  3   d  having corrugation is formed at the base portion  3   a  on the medial and lateral sides of the heel portion of the outsole  3 . A dashed line L of FIG. 2A indicates a ridge line and a trough line of the outsole corrugated portion  3   d.    
     The midsole  4  is placed on the upper face of the base portion  3   a  of the outsole  3 . A midsole corrugated portion  4   d  having corrugation, shown in FIG. 1, is formed on the lower face of the heel portion of the midsole  4 . The shape of the midsole corrugated portion  4   d  corresponds to that of the outsole corrugated portion  3   d.    
     The midsole  4  is generally formed of a soft elastic material having good cushioning properties. Specifically, thermoplastic synthetic resin foam such as ethylene-vinyl acetate copolymer (EVA), thermosetting resin foam such as polyurethane (PU), or rubber material foam such as butadiene or chloroprene rubber are used. 
     In this embodiment, since the outsole corrugated portion  3   d  is formed on the medial and lateral sides of the heel portion of the outsole  3  and the corresponding midsole corrugated portion  4   d  is formed on the lower face of the heel portion of the midsole  4 , the corrugated contact faces between the outsole  3  and the midsole  4  generate a resistant force preventing the heel portion of the midsole  4  from deforming laterally at the time of contacting the ground. Thereby, sideways or lateral slanting of the heel region of the shoe can be prevented and running stability is secured. 
     Moreover, the sole structure of this embodiment is formed of double layers with the midsole  3  and the outsole  4 , which decreases the number of components and the weight of the sole structure, simplifies a manufacturing process, and reduces a manufacturing cost. Furthermore, since the sole structure becomes thinner, its bendability or flexibility can be improved. 
     Also, in this embodiment, as shown in FIGS. 2B and 2C, each of the cleats  5  at the heel region of the shoe  1  is disposed between a trough and the adjacent trough of the corrugated portion  3   d  of the outsole  3  (see FIG.  7 ). Thereby, an upper force applied to the outsole  3  from the ground is transmitted and dispersed to both the troughs  30  and  31  through the cleats  5 . Thus, the upper force is absorbed and effectively relieved by the troughs  30 ,  31 . 
     FIG. 3 depicts a spiked shoe for baseball of a second embodiment of the present invention. As shown in FIG. 3, a baseball shoe  10  has a sole structure that is formed of a midsole  14  provided under an upper  12  and extending from a heel region to a forefoot region of the shoe  10  and an outsole  13  provided under the midsole  14  and directly contacting the ground. On the lower surface of the outsole  13  a plurality of cleats or spikes  15  are provided. 
     The midsole  14  is formed of an upper midsole  14   a  attached to the bottom face of the upper  12  and a lower midsole  14   b  provided under the upper midsole  14   a . A corrugated sheet or wavy plate  16  having corrugation on its medial and lateral sides is interposed between the upper midsole  14   a  and the lower midsole  14   b  at the heel region of the shoe  10 . The corrugated sheet  16  has upraised side portions  16   a  and  16   b , shown in FIGS. 4B and 4C, extending upwardly on the medial and lateral sides of the heel portion. The upper midsole  14   a  has a through hole  17  formed thereinto in the lateral direction. The midsole  14 , as with the soccer shoe shown in FIG. 1, is formed of a soft elastic material having good cushioning properties, such as thermoplastic or thermosetting resin foam, rubber material foam or the like. 
     As shown in FIGS. 4B and 4C, an outsole corrugated portion  13   d  is formed on the medial and lateral sides of the heel portion of the outsole  13 . A dashed line L of FIG. 4A illustrates a ridge or crest line and a trough line of the outsole corrugated portion  13   d . A lower midsole corrugated portion  14   d , which corresponds to the outsole corrugated portion  13   d , is formed on the medial and lateral sides of the heel portion of the lower midsole  14   b . Similarly, an outsole corrugated portion  13   e  is formed on the medial and lateral sides of the forefoot portion of the outsole  13 . An upper midsole corrugated portion  14   e , which corresponds to the outsole corrugated portion  13   e , is formed on the medial and lateral sides of the forefoot portion of the upper midsole  14   a.    
     In this embodiment, since the outsole corrugated portion  13   d  is formed on the medial and lateral sides of the heel portion of the outsole  13  and the corresponding lower midsole corrugated portion  14   d  is formed on the lower face of the heel portion of the lower midsole  14   b , the corrugated contact faces between the outsole  13  and the lower midsole  14   b  generate a resistant force preventing the heel portion of the midsole  14  from deforming laterally at the time of contacting the ground. Thereby, sideways or lateral slanting of the heel region of the shoe can be prevented and running stability is secured. 
     Moreover, in this embodiment, since the corrugated sheet  16  is interposed between the upper and lower midsoles  14   a  and  14   b , transverse or lateral slanting of the heel region of the shoe can be more securely prevented owing to the corrugation of the corrugated sheet  16  that increases a compressive hardness of the midsole  14 . Additionally, the corrugated sheet  16  may have a smaller shape than an outer circumferential shape of the heel portion of the outsole  13 . In this case, the corrugated sheet placed inside the heel region does not appear on the medial and lateral sides of the heel region of the shoe. 
     Furthermore, in this embodiment, since the forefoot region of the shoe is formed of a sole structure with double layers of the outsole  13  and the upper midsole  14   a , the number of shoe components is decreased, and thus, a lighter weight is achieved and a manufacturing process is simplified and a manufacturing cost is reduced. Also, as the sole structure is made thinner, bendability or flexibility of the forefoot region of the shoe is advanced. 
     Moreover, as the outsole corrugated portion  13   e  and the corresponding upper midsole corrugated portion  14   e  are formed at the forefoot region of the shoe  10 , the corrugated contact faces between the outsole  13  and the upper midsole  14   a  generate a resistant force preventing the forefoot portion of the midsole  14  from deforming laterally or transversely at the time of contacting the ground. Thereby, sideways or lateral slanting of the forefoot region of the shoe can be prevented. 
     Also, in this embodiment, as shown in FIGS. 4B and 4C, each of the cleats  15  at the heel region of the shoe  10  is disposed at a trough of the outsole corrugated portion  13   d  (see FIG.  7 ). Thereby, an upper force applied to the outsole  13  from the ground is relieved through deformation of the trough. Similarly, as each of the cleats  15  provided specifically on the medial side of the forefoot region is disposed at a trough of the outsole corrugated portion  13   e , not only bendability or flexibility of the forefoot portion is maintained but also the upper force applied to the forefoot region is effectively relieved. 
     FIG. 5 illustrates a golf shoe of a third embodiment of the present invention. As shown in FIG. 5, a golf shoe  20  has a sole structure that is formed of an upper midsole  24   a  provided under an upper  22  and extending from a heel region to a forefoot region of the shoe  20 , an outsole body  23  provided under the upper midsole  24   a , a lower midsole  24   b  provided under the heel portion of the outsole body  23 , and an outsole heel portion  28  attached under the lower midsole  24   b . The outsole body  23  has upraised side portions  23   a  and  23   b , shown in FIGS. 6B and 6C, extending upwardly on the medial and lateral sides of the heel portion. On the lower surfaces of the outsole heel portion  28  and the forefoot and midfoot portions of the outsole body  23  are provided a plurality of cleats  25 . A laterally extending through hole  27  is formed in the upper and lower midsoles  24   a  and  24   b . The midsole  24 , as with the soccer shoe in FIG.  1  and the baseball shoe in FIG. 3, is formed of a soft elastic material having good cushioning properties, such as thermoplastic or thermosetting resin foam, rubber material foam or the like. 
     As shown in FIGS. 6B and 6C, an outsole corrugated portion  23   d  is formed at the heel portion of the outsole body  23 . A dashed line L of FIG. 6A indicates a ridge line and a trough line of the outsole corrugated portion  23   d . A lower midsole corrugated portion  24   d , which corresponds to the outsole corrugated portion  23   d , is formed at the lower midsole  24   b . Similarly, an outsole corrugated portion  23   e  is formed at the forefoot portion of the outsole body  23 , and an upper midsole corrugated portion  24   e , which corresponds to the outsole corrugated portion  23   e , is formed at the forefoot portion of the upper midsole  24   a . The wavelength of corrugation of the outsole corrugated portion  23   e  is relatively larger on the lateral side and relatively smaller on the medial side and trough line L are disposed radially. 
     In this embodiment, since the outsole corrugated portion  23   d  is formed at the heel portion of the outsole body  23 , a resistant force occurs that restrains the heel portion of the midsole  24  from deforming laterally on contacting the ground. Thus, lateral slanting of the heel region of the shoe can be prevented and walking stability and swinging balance can be secured. 
     Moreover, in this embodiment, the sole structure of the forefoot region of the shoe is formed of double layers with the upper midsole  24   a  and the outsole body  23 , which decreases the number of components and the weight of the structure, simplifies a manufacturing process, and reduces a manufacturing cost. Furthermore, since the sole structure becomes thinner, bendability or flexibility of the forefoot region of the shoe can be improved. 
     Furthermore, in this case, since the outsole corrugated portion  23   e  is formed at the forefoot portion of the outsole body  23 , the forefoot region of the shoe is prevented from leaning in the lateral direction. Moreover, since each of the cleats  25  at the forefoot region of the shoe are disposed between a trough and the adjacent trough of the corrugation of the outsole corrugated portion  23   e , the upper force applied to the outsole body  23  from the ground can be effectively absorbed and relieved through deformation of the trough portion of corrugation and bendability of the outsole body  23  can be maintained. 
     Those skilled in the art to which the invention pertains may make modifications and other embodiments employing the principles of this invention without departing from its spirit or essential characteristics particularly upon considering the foregoing teachings. The described embodiments and examples are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. Consequently, while the invention has been described with reference to particular embodiments and examples, modifications of structure, sequence, materials and the like would be apparent to those skilled in the art, yet fall within the scope of the invention.