Patent Publication Number: US-6338206-B1

Title: Athletic shoe sole design and construction

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to an athletic shoe sole design and construction, and more particularly, to a sole assembly having a vent or a vent hole formed in a midsole. 
     The sole of an athletic shoe is generally comprised of a midsole and an outsole. The midsole is typically formed of soft elastic material in order to ensure adequate cushioning properties. The outsole is fitted under the midsole and directly contacts with the ground. 
     Preferably, ventilation of a shoe is secured in a degree when wearing a shoe. Various kinds of shoes with vent holes have conventionally been proposed. 
     For instance, the Japanese patent application laying open publication No.  8-131204  discloses a plurality of transverse holes formed at a body portion of the bottom member of a shoe and a plurality of vertical holes also formed at a body portion of the bottom member. The vertical holes communicate with the transverse holes and penetrate through the insole. The Japanese utility model application examined publication No.  63-43923  shows a plurality of through holes penetrating through the upper member of a sole in the thickness direction and a plurality of grooves formed at the lower member of the shoe. Each of the grooves corresponds to each of the through holes. 
     In both cases, the air flows into a shoe through the transverse holes and the vertical holes, or the through holes and the grooves. Thus, ventilation of the inside of a shoe is acquired. 
     On the other hand, in an athletic shoe, especially in the case of a running shoe, higher flexibility of the forefoot portion is required. In the prior art construction, however, transverse holes or grooves are merely formed on the body portion or the lower member made of rubber or the like. Thus, these transverse holes and grooves, which are made only in the light of ventilation, cannot satisfy higher flexibility that are required in an athletic shoe. 
     The object of the present invention is to provide a sole assembly for an athletic shoe that can realize higher flexibility as well as ventilation of the forefoot portion of a shoe. 
     SUMMARY OF THE INVENTION 
     The present invention provides a sole assembly for an athletic shoe. 
     In one embodiment, a sole assembly comprises a midsole extending from the heel portion to the forefoot portion, a curved or bent groove formed on the bottom side of the forefoot portion of the midsole and extending in the general shoe width direction, a through hole that is open on the plantar contact face of the midsole and formed in the curved groove, and a cover portion that covers the curved groove. The curved groove and the cover portion form an air tube. 
     The air tube may be open at one end or at both ends. An openable and closable valve means may be provided at the opening portion of the air tube. The valve means may be formed of a projection or a protrusion at the bottom portion of the curved groove in the vicinity of the opening portion. 
     Alternatively, the air tube may be closed at its both ends and an open air intake port communicating with the through hole in the curved groove may be formed at either the midfoot portion or the heel portion of the midsole. Also, the cover portion may be formed integrally with an outsole disposed on the bottom side of the forefoot portion of the midsole. 
     In use of a shoe, the air is introduced or flows into the inside of the shoe through the curved groove and the through hole, and thus, ventilation can be acquired inside the forefoot portion of the shoe. Moreover, in this case, the thickness of the midsole is smaller at the curved groove formed portion, which causes the midsole to be easier to bend in the vertical direction along the curved groove, thereby improving flexibility or bendability of the forefoot portion. This improved flexibility can realize smoother transfer of the load and secure gripping properties when an athlete or a shoe wearer gets down onto the ground from the heel portion to the toe portion of the shoe. 
     Furthermore, the opening portion of the through hole on the bottom side is prevented from being exposed to the ground by the cover portion. Thereby, water, sand, dust, and the like outside the shoe are blocked from entering the inside of the shoe via the through hole when the shoe contacts with the ground. In such a way, the shoe can be used as an outdoor shoe as well. 
     When at least one end of the air tube is open, the open air is introduced into the curved groove through the opening end of the air tube and flows into the inside of the shoe via the through hole from the curved groove. 
     When the openable and closable valve means is provided, the valve means closes the opening portion of the air tube at the time of bending of the forefoot portion, thereby increasing the air pressure inside the air tube. The pressure increased air in the air tube easily flows into the inside of the shoe via the through hole, which improves ventilation of the shoe. 
     When a projection or protrusion is provided in the curved groove, it contacts with the cover portion at the time of bending of the forefoot portion, thereby closing the opening portion of the air tube. In this case, because the valve means is formed of a mere projection or protrusion, the structure of the valve means can be simplified. 
     When both ends of the air tube are closed, the air pressure inside the air tube easily increases at the time of bending of the forefoot portion and the pressure increased air is pushed out of the through hole and flows into the inside of the shoe. In this case, the open air is introduced into the air tube through the intake port formed at the midfoot portion and/or the heel portion of the midsole. Thus, the supply of air to the air tube can be conducted with ease. Additionally, integral formation of the cover portion with the outsole can simplify the whole structure of the sole. 
    
    
     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 lateral side view of an athletic shoe (left foot side) incorporating the sole construction of the present invention. 
     FIG. 2 is a bottom view of the left foot side sole construction of the present invention. 
     FIG. 3 is a lateral side view of the sole construction of FIG.  2 . 
     FIG. 4 is an enlarged view of a portion of FIG.  3 . 
     FIG. 5 is a cross sectional view of FIG. 2 taken along line V—V. 
     FIG. 6 is a perspective view of the upper midsole of the sole construction of FIG. 2, showing a corrugated sheet fitted on the bottom side of the upper midsole. 
     FIG. 7 shows an alternative embodiment of FIG.  4 . 
     FIG. 8 is a schematic illustrating the action of the valve means of FIG.  7 . 
     FIG. 9 shows an alternative embodiment of FIG.  2 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Turning now to the drawings, FIG. 1 illustrates an athletic shoe incorporating the sole construction of the present invention. The sole of this athletic shoe  1  comprises a midsole  3 , a corrugated sheet  4  and an outsole  5  directly contacting with the ground. The midsole  3  is fitted to the bottom of an upper  2 . The corrugated sheet  4  having a wavy configuration is interposed in the midsole  3 . The outsole  5  is fitted to the bottom of the midsole  3 . 
     The midsole  3  is provided in order to absorb impact load imparted on the bottom of the shoe  1  when an athlete gets down onto the ground. The midsole  3  is comprised of an upper midsole  3   a  and a lower midsole  3   b  that are respectively disposed on the top and bottom surfaces of the corrugated sheet  4 . That is, the corrugated sheet  4  is interposed between the upper midsole  3   a  and the lower midsole  3   b,  and the sheet  4  is integrated with the upper and lower midsoles  3   a,    3   b.  Also, the upper midsole  3   a  extends from the heel portion to the forefoot portion of a shoe  1 , whereas the lower midsole  3   b  is disposed mainly at the heel portion. 
     The midsole  3  is generally formed of 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. 
     The corrugated sheet  4  is preferably formed of thermoplastic resin such as thermoplastic polyurethane (TPU) of comparatively rich elasticity, polyamide elastomer (PAE), ABS resin or the like. Alternatively, the corrugated sheet  4  is formed of thermosetting resin such as epoxy resin, unsaturated polyester resin and the like. The corrugated sheet may be formed of a plate made of elastic metal, or a meshed sheet made of elastic metal fibers. 
     At the contact portions of the midsole  3  with the corrugated sheet  4  are formed a plurality of transverse holes  6 ,  7  extending laterally (into the page of FIG.  1 ). These holes  6 ,  7  are provided for improving cushioning properties of the midsole  3  and decreasing its weight. 
     As shown in FIGS. 2 and 3, a curved groove  34 , which extends substantially laterally, or in the general shoe width direction, is formed on the bottom side of the forefoot region A of the upper midsole  3   a.  A plurality of vertically extending through holes  35  are formed to extend vertically through the upper midsole  3   a  and communicate into the curved groove  34 . The through holes  35  are open on the plantar contact face  30  of the upper midsole  3   a,  shown in FIGS. 5 and 6. 
     The curved groove  34  is covered with the resin mold cover portion  50 , which is integrally formed with the outsole  5 , mentioned hereinafter. The space surrounded by the curved groove  34  and the cover portion  50  creates an air tube  36 , as is clearly seen in FIG.  4 . Both ends of the air tube  36  are open at the medial and lateral sides of the shoe. Preferably, the cover portion  50  has a bent shape toward the bottom face of the curved groove  34  so that the cover portion  50  can return to its original position with ease after bent deformation of the forefoot portion of the shoe. 
     A plurality of grooves  33  communicating with the through holes  35  in the curved groove  34  are formed in the bottom surface of the upper midsole  3   a  at the forefoot region A of the upper midsole  3   a.  A vertically extending through hole  31  is formed in the upper midsole  3   a  at the midfoot region B, or the plantar arch portion, of the upper midsole  3   a . At the opening portion of the through hole  31  on the bottom side of the upper midsole  3   a,  there is formed a concave portion  32 , or a recess, in communication with the grooves  33 . The corrugated sheet  4  extends from the heel region C to the midfoot region B, or a plantar arch portion, of the midsole  3 , and it is comprised of a heel portion  4   a  having a corrugated configuration and a generally planar midfoot portion  4   b  formed integrally with the heel portion  4   a.  The broken lines extending in the lateral direction at the heel portion  4   a  of FIG. 2 each respectively show a crest or a trough of the corrugation of the corrugated sheet  4 . 
     As shown in FIGS. 2 and 6, the recess  32 , which is formed at the midfoot region B of the upper midsole  3   a,  is covered with the midfoot portion  4   b  of the corrugated sheet  4  and the midfoot portion  4   b  is formed with a pair of slits  42 , which are disposed opposite to (i.e. in registration with) the recess  32 , but not in registration with the through hole  31 . 
     The outsole  5 , shown in FIGS. 2 and 3, is comprised of a heel portion  5   a  placed on the bottom face of the lower midsole  3   b  and forefoot portions  5   b  and  5   c  that are placed mainly on the forefoot region A of the upper midsole  3   a.  The heel portion  5   a  is separated from the forefoot portions  5   b,    5   c.  The forefoot portions  5   b,    5   c  are integrated with each other by the cover portion  50  extending along the curved groove  34 . 
     In use of the shoe, the air, which has been introduced into the air tube  36  from the opening portions  34   a,    34   b  on the medial and lateral sides, flows into the inside of the shoe via the through holes  35 , thereby acquiring ventilation of the forefoot portion inside the shoe. 
     Also, the air, which has been introduced into the recess  32  of the upper midsole  3   a  from the slits  42  of the corrugated sheet  4 , flows into the midfoot region B inside the shoe via the through hole  31  and also flows into the through hole  35  via the groove  33 . 
     Moreover, in this case, the thickness of the upper midsole  3   a  is made smaller at the curved groove  34  compared to the other portions of the midsole  3   a,  which facilitates bending of the upper midsole  3   a  in the vertical direction along the curved groove  34 , thereby improving flexibility, or bendability, of the upper midsole  3   a.  Also, improved flexibility of the upper midsole  3   a  allows for smoother transfer of the load and secures gripping properties when an athlete lands on the ground from the heel portion to the toe portion of the shoe. 
     Furthermore, the opening portion of the through hole  35  on the bottom side is prevented from being exposed to the ground by the cover portion  50 . Thereby, water, sand, dust, and the like outside the shoe are blocked from entering the inside of the shoe via the through hole  35  when the shoe contacts with the ground. In such a way, the shoe can be used as an outdoor shoe. 
     Also, in this case, because the cover portion  50  is integrally formed with the forefoot portion  5   b,    5   c  of the outsole  5 , the whole shoe structure can be simplified. In addition, when the cover portion  50  is formed of the transparent resin, the through hole can be seen from the bottom side of the shoe (see e.g. FIG. 2 ), which can improve the aesthetic impression. 
     In another embodiment, a valve member, which can open and close the air tube  36 , may be employed at the opening portions  34   a,    34   b  on both sides of the curved groove  34 . 
     FIG. 7 shows such a valve member of the sole construction. In FIG. 7, a projection or a protrusion  37  is formed on the bottom side of the curved groove  34  in the vicinity of the opening portion and each of the opening portions  34   a,    34   b  of the curved groove  34  is narrower compared to the above-identified embodiment shown in FIGS. 1-6. 
     When the forefoot portion of the shoe bends from the condition shown in FIG. 7, the upper midsole  3   a  is bent and deformed into the shape shown in FIG.  8 . Then, the protrusion  37  comes in contact with the cover portion  50  and the opening portions  34   a,    34   b  are forced to be closed, which increases the air pressure inside the air tube  36 . The pressure increased air in the air tube  36  easily flows through the through hole  35  and into the inside of the shoe, thereby advancing ventilation of the shoe. 
     Additionally, the groove or grooves  33  formed in the upper midsole  3   a  may be omitted in the embodiments shown in FIGS. 1-8. This is so because the open air can flow into the curved groove  34  mainly through the opening portions  34   a,    34   b  on both sides of the curved groove  34  rather than through the groove  33 . In such a way, the air can be supplemented into the air tube  36 . 
     In still another embodiment, one end or both ends of the curved groove  34  may be tightly closed. FIG. 9 shows such a curved groove  34  one end of which is closed, or not open. At the time of bending of this forefoot portion, the air pressure in the air tube  36  easily increases, thereby allowing the pressure increased air in the air tube  36  to smoothly enter the inside of the shoe via the through hole  35 , which can improve ventilation of the shoe. 
     In this embodiment as well, the valve member shown in FIG. 7 may be employed at the opening portion  34   a  of the curved groove  34 . Thus, improved ventilation can be acquired. 
     On the other hand, when the both ends of the curved groove  34  are closed, or not open, the air is supplemented into the air tube  36  through the slit  42  of the corrugated sheet  4  to the recess  32  and through the groove  33  of the upper midsole  3   a.    
     The recess  32 , or concave portion, communicating with the groove  33  may be formed on the heel region C of the upper midsole  3   a.  In this case, the slit  42  corresponding to the recess  32  is formed on the heel portion  4   a  of the corrugated sheet  4 . When the slit  42  is provided on the forefoot portion  4   b  or the heel portion  4   a  of the corrugated sheet  4 , the position of the slit  42  is placed at a concave portion located away from the ground contact face of the shoe. Thus, water, sand, dust, and the like outside the shoe are prevented from entering the slit. The cover  50  is preferably integral with the outsole  5 , but it can be separated from the outsole  5 . 
     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 still fall within the scope of the invention.