Patent Publication Number: US-6212795-B1

Title: Shoe sole with reinforced support structure

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a shoe sole having reinforced structure. 
     2. Description of the Related Art 
     It is well known to have a reinforcing member in the arch portion of the sole of a shoe conforming to the shape of the treadless portion of the midsole, i.e., the portion of the midsole not attached to an outer sole that does not have ground contact when the outer sole is grounded. Such reinforcing device reinforces the rigidity of the treadless portion of the midsole by suppressing the deformation of the midsole. These known devices are exemplified those shown in FIGS.  6 ( a ) and  6 ( b ) and FIGS.  7 ( a ) and  7 ( b ), herein. 
     FIG.  6 ( a ) exemplifies the side elevation of a prior art shoe sole disclosed in the Japanese Laid-Open Utility Model Publication (unexamined) No. 7-34703 (Published on Jun. 27, 1995). FIG.  6 ( b ) is the bottom view of such prior art shoe sole. In this prior art shoe sole, the reinforcing member  3  of the treadless portion of the midsole is an integrally formed member that includes an arch portion  3   a,  a front support portion  30  at the front end of the sole and a rear support portion  31  at a rear end of the sole. The arch portion  3   a  is affixed on its back face to the midsole  2 . The front support portion  30  and the rear support portion  31  are disposed, respectively, at the front and rear of the arch portion  3   a.  The front support portion  30  is sandwiched between the midsole  2  and an outer sole  1  below the midsole  2 . The front support portion  30  is supported on a front supporting face  1 F of the upper surface of the outer sole  1 . The rear support portion  31  is sandwiched between the midsole  2  and the outer sole  1 . The rear support portion  31  is supported on a rear supporting face  1 B of the upper face of the outer sole  1 . 
     FIG.  7 ( a ) exemplifies the side elevation of another prior art shoe sole as disclosed in the Japanese Patent Publication (unexamined) No. 7-79804 (Published on Mar. 28, 1995). FIG.  7 ( b ) is a bottom side perspective view of such prior art shoe sole. This sole is substantially similar to the aforedescribed prior art sole. 
     Additionally, the reinforcing device  3  is made of a sufficiently soft or flexible material to permit the shoe sole to have a torsional motion. Because of this, the front support portion  30  and the rear support portion  31  of the reinforcing device  3  can displace longitudinally upon the grounding of the sole. This can cause the reinforcing device  3  to longitudinally extend, flattening the arch portion  3   a  of the reinforcing device  3 . This causes the treadless portion of the midsole  2  to depress toward the ground causing stress on the arch of the foot. 
     SUMMARY OF THE INVENTION 
     It is an object of this invention to provide a reinforcing support structure for the treadless portion of the midsole of the shoe to prevent the arch portion of the midsole from flattening. 
     The foregoing object as well as others is accomplished by the shoe sole of this invention that has an integrally reinforced portion. The shoe sole comprises an outer sole having a ground contact surface and an opposite upper surface and a midsole having portions thereof attached to and covered by the upper surface of the outer sole. A treadless portion of the midsole which is not attached to the upper surface of the outer sole and does not have ground contact when the ground contact surface of the outer sole is grounded has an arched support member. The support member comprises an arched portion, a front support portion disposed in front of the arched portion and a rear support portion disposed in the rear of the arched portion. The arched portion is affixed to the treadless portion of the midsole. The front support portion of the arched portion is affixed and sandwiched between the midsole and the outer sole below the midsole and supported on a front supporting face of the upper surface of the outer sole. The rear support portion is affixed and sandwiched between the midsole and the outer sole and supported on a rear supporting face of the upper surface of the outer sole. 
     The front supporting face of the upper surface of outer sole has a tapered inclined face ascending as it inclines in the forward direction and the front support portion of the arched support member is supported by such inclined face. Thus, the front support portion of the arched support member is inhibited from moving in a direction that opens the arched portion of the support member when the outer sole is grounded. 
     According to another aspect of the invention, additionally or alternatively, the rear supporting face of the upper surface of outer sole has a tapered inclined face ascending as it inclines in the backward direction. Thus the rear support portion of the arched support member is supported by the inclined face and is inhibited from moving in a direction that opens the arched portion of the support member when the outer sole is grounded. 
     According to yet another aspect of the invention, additionally or optionally, the rear supporting face of the upper surface of outer sole has a tapered inclined face descending as it inclines in the backward direction. Thus the rear support portion of the arched support member is supported by the inclined face and is inhibited from moving in a direction that opens the arched portion of the support member when the outer sole is grounded. 
     In accordance with this invention, when the sole of the shoe lands (or grounds), the front support portion and the rear support portion of the arched support member are clamped between the outer sole and the midsole. By these clamping actions, the front support portion and the rear support portion of the arched support member are difficult to displace (or move) forward and backward when a load is applied from above the arch at the time of landing. This inhibits or prevents the arch portion from being deformed to a flattened position thereby to suppress the depression of the treadless portion of the midsole. 
     In the preferred embodiment of this invention, the front support portion and the rear support portion of the arched support member are each supported by an inclined face to thus provide a wedged type structure. This wedging action suppresses the forward displacement of the front support portion and/or the backward displacement of the rear support portion. As a result, it is possible to suppress the depression or flattening of the treadless portion of the midsole. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be more clearly understood from the following description of its preferred embodiments, as made with reference to the accompanying drawings. However, those embodiments and drawings are presented merely for illustrations and explanations. This scope of the invention is defined on the basis of the appended claims. In the accompanying drawings, the common reference numerals designate identical or corresponding portions. 
     FIG.  1 ( a ) is a sectional view schematically showing one embodiment of a support structure, i.e., an arched support member, used in this invention. FIG.  1 ( b ) is a sectional view schematically showing another embodiment of a support structure used in this invention. FIG.  1 ( c ) is a sectional view schematically showing a third embodiment of the support structure used in this invention. 
     FIGS.  2 ( a ) and  2 ( b ) show yet another embodiment of the invention. FIG.  2 ( a ) is a bottom view of a shoe sole before an outer sole is mounted, and FIG.  2 ( b ) is a side elevation of such shoe sole with the outer sole mounted on the midsole. 
     FIG.  3 ( a ) is a bottom view of a pair of arched support reinforcing members or devices used in FIGS.  2 ( a ). FIG.  3 ( b ) is a side elevation of such reinforcing device for use on a right shoe. FIG.  3 ( c ) is a sectional view taken along line IIIc—IIIc of FIG.  3 ( a ). 
     FIG. 4 is a side elevation of a shoe sole that includes yet another embodiment of this invention. 
     FIG.  5 ( a ) is a side elevation showing another embodiment of this invention. FIG.  5 ( b ) is a sectional view of the embodiment depicted in FIG.  5 ( a ). FIG.  5 ( c ) is a sectional view of the embodiment depicted in FIG.  5 ( a ) with modifications thereto. 
     FIG.  6 ( a ) is a schematic side elevation of a prior art shoe sole. FIG.  6 ( b ) is a schematic bottom view of the prior art shoe sole depicted in FIG.  6 ( a ). 
     FIG.  7 ( a ) is a side elevation of another prior art shoe sole. FIG.  7 ( b ) is a bottom perspective view of of the prior art shoe sole depicted in FIG.  7 ( a ). 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     This invention will be described in connection with its embodiments with reference to the accompanying drawings. The description herein is primarily directed to the portions of the invention which are different from the prior art depicted, i.e., FIGS.  6 ( a ) and  6 ( b ). A detailed description of the elements that are similar to that of the prior art depicted will be omitted and/or will be designated by the same reference numerals. 
     Principle Embodiment 
     The basic structure and principle of this invention will be described with reference to the embodiment depicted in FIG.  1 ( a ). 
     In FIG.  1 ( a ), wherein the F arrow is the direction toward the front of the shoe and the B arrow is the direction toward the rear or back of the shoe, the arched support member/a reinforcing device  3  of a shoe sole is provided with a front support portion  30  at the front end and a rear support portion  31  at the rear end. These support portions are integrally molded with an arch portion  3   a  to form a molded, one piece, arched support member  3 . The front support portion  30  and the rear support portion  31  are disposed respectively at the front and rear end portions of the arched support member  3 . These individual support portions  30  and  31  are clamped between an outer sole  1  and a midsole  2  of a shoe sole S. As depicted in FIG.  1 ( a ), the arched support member  3  receives a load W from above when the sole is grounded. This clamping action of the support portions  30 ,  31  between the outer sole  1  and midsole  2  inhibits or prevents the front support portion  30  and the rear support portion  31  of the reinforcing device  3  from moving in a direction to open the arch portion  3   a  of the reinforcing device  3  when the shoe sole S is grounded. 
     More specifically, still referring to FIG.  1 ( a ), upon grounding, the arch portion  3   a  wants to deform and flatten due to the vertical load W applied to the shoe sole S. Counteracting this tendency is the fact that the front support portion  30  and the rear support portion  31  of the reinforcing device  3  are clamped/affixed between the outer sole  1  and the midsole  2 . This structure prevents the front support portion  30  and the rear support portion  31  from being displaced forward F and backward B. This thus reduces the vertical displacement of the arch portion  3   a.    
     Referring to the embodiment depicted in FIG.  1 ( a ), the front support portion  30  of the reinforcing device  3  is supported on a tapered first inclined face  10  which is inclined to ascend as it goes forward F. This forms, in effect, a wedge. Thus in this embodiment, the front support portion  30  is supported on the first inclined face  10 , i.e., the support portion  30  is supported by the formed wedge. As a result of this wedging effect, the front support portion  30  is prevented from moving forward F so that the arch portion  3   a  remains or tends to remain open. 
     Referring to FIG.  1 ( b ), in this embodiment for a similar reason, the rear support portion  31  of the reinforcing device  3  is supported on a tapered inclined face  11  which is inclined to ascend as it goes backward B. This also contributes to maintaining the arch portion  3   a  in a stable or open position. 
     Referring to another embodiment depicted in FIG.  1 ( c ), the rear support portion  31  is supported on a tapered inclined face  12  which is inclined to descend as it goes backward B. Such an inclination of the face  12  also produces a wedging effect or action. This is due to the fact that upon grounding, the outer sole  1  is grounded sequentially first from the back or rear B of the sole and then forward to the front F of the sole. However, the load W that is applied to the arch portion  3   a  is generally at its maximum when the outer sole  1  is grounded in front and at the back of the arch. It is, therefore, more effective and preferred to provide the inclined face  11  depicted in FIG.  1 ( b ) rather than the inclined face  12  depicted in FIG.  1 ( c ). 
     In all of the embodiments depicted in FIGS.  1 ( a-c ), the preferred angle of inclination θ for each inclined face  10 ,  11  and  12  with respect to a horizontal plane is preferably at least about 3 Degrees or more, and most preferably at least about 5 Degrees or more. On the other hand, an area A of each inclined face  10 ,  11  and  12  is generally set to have a value of preferably at least about 0.8 cm 2  or more and most preferably at least about 2 cm 2  or more so as to clamp the individual support portions  30  and  31  sufficiently between the outer sole  1  and the midsole  2 . 
     Specific Embodiments 
     Another embodiment of this invention is depicted in FIGS.  2 ( a ),( b ) and FIGS.  3 ( a ),( b ),( c ). 
     FIG.  2 ( a ) is a bottom view of the shoe sole S before the outer sole  1  is fixed thereto. At the treadless portion S 1  of the midsole  2  of the shoe sole S, a pair of reinforcing arched support members  3 , shown in detail in FIG.  3 ( a ), are fixed on the back face of the midsole  2 . As shown in FIGS.  3 ( a ) and  2 ( a ), the front support portion  30  and the rear support portion  31  are hatched. Referring to FIGS.  2 ( a ) and  2 ( b ), below (toward the ground) the front support portion  30  and the rear support portion  31  (as hatched), there is fixed the outer sole  1 —see FIG.  2 ( b ). This outer sole  1  has a treading face  1   a  on its outer surface and is generally made of a foam or non-foam of rubber or resin. The midsole  2  is sandwiched between the upper (not-shown), as suited for enveloping the instep of a foot, and the outer sole  1  so that it absorbs the shocks upon landing and exhibits a repulsive force upon stepping. Generally, the midsole  2  is made of a foam of EVA or polyurethane and can include, for example, a cushioning system that includes air or a silicon gel. The arched support member or reinforcing device  3  is preferably made of a resilient, non-foam polymer. 
     Referring to FIG.  2 ( b ), the outer sole  1  is provided with a front supporting face  1 F for supporting the front support portion  30 , and a rear supporting face  1 B for supporting the rear support portion  31 . The front supporting face  1 F is set generally horizontally. The rear supporting face  1 B is provided with the tapered inclined face  12  which is inclined to descend as it goes backward B. The rear support portion  31  is supported by the inclined face  12 . 
     Still referring to FIG.  2 ( b ), the inclined face  12  is formed to make the outer sole  1  generally gradually thinner as it goes toward the back B. As used herein, the phrase “generally gradually thinner” means the change in the thickness of the sole excluding the small antislipping rough surrface on the bottom face of the outer sole  1 . 
     Referring to FIGS.  3 ( a ) and  3 ( c ), the rear support portion  31  has an annularly shaped portion  31   a.  A cup-shaped portion  31   b  is formed integrally with the rear support portion  31  at the center of the annular portion  31   a.  FIG.  3 ( b ) is a side elevation of the arched support member  3  of a right shoe and FIG.  3 ( c ) is a sectional view taken along line IIIc—IIIc of FIG.  3 ( a ). 
     The cup-shaped portion  31   b  is formed integrally with the rear support portion  31  so that the rigidity of the rear support portion  31  is enhanced so that the arch portion  3   a  of the arched support member  3  is more difficult to flatten. 
     The cup-shaped portion  31   b  need not be smoothly curved, as long as it is generally “cup shaped”. In the embodiment depicted in FIGS.  2 ( a ), ( b ) and FIGS.  3 ( a-c ), the cup-shaped portion  31   b  is recessed toward the midsole  2 , however, optionally, it may protrude toward the grounding side. 
     Referring to FIG. 4 in conjunction with FIG.  1 ( c ), this drawing depicts another embodiment similar to that shown in FIG.  1 ( c ), wherein the support portions  30  and  31  are supported by the inclined faces  10  and  12 , respectively. In the embodiment depicted in FIG. 4, the arched support member or reinforcing device  3  is hatched to clearly indicate this essential element. 
     Still referring to FIG. 4, the front supporting face  1 F of the outer sole  1  is provided with the tapered first inclined face  10  which is inclined to ascend as it goes forward F. The front support portion  30  of the reinforcing device  3  is supported by this first inclined face  10 . This inclined face  10  is generally shaped so that the outer sole  1  gradually becomes thicker as it goes forward F. 
     The rear supporting face  1 B of the outer sole  1  is provided with a tapered inclined face  12  which is inclined to descend as it goes backward B. The rear support portion  31  of the reinforcing device  3  is supported on this inclined face  12 . This inclined face  12  is generally shaped so that the outer sole  1  gradually thinner as it goes backward B. 
     FIGS.  5 ( a ), 5 ( b ),  5 ( c ) depict another embodiment of this invention. 
     In this embodiment, the outer sole  1  of the front foot part is fixed on the bottom face of a nonwoven fabric  4 . The front support portion  30  is sandwiched between the outer sole  1  and the midsole  2  with the nonwoven fabric  4 . The front supporting face  1 F of the outer sole  1  supporting the front support portion  30  is set generally horizontally. The rear support portion  31  is supported on the rear supporting face  1 B of the outer sole  1 . 
     The rear supporting face  1 B is continuously formed and includes a horizontal face  13 , an inclined face  11  and another inclined face  12 . The horizontal face  13  also supports the rear support portion  31  of the reinforcing device  3 . 
     In this embodiment, to form the inclined face  11 , the outer sole  1  becomes gradually thicker as the inclined face  11  goes backward B. In the portion of the other inclined face  12 , on the other hand, the outer sole  1  is made generally gradually thinner as the inclined face  12  goes backward B. 
     Optionally, as shown in FIG.  5 ( c ), the inclined face  11  may be made annular to form the cup-shaped portion  31   b  therein. 
     Although the preferred embodiments have been described with reference to the accompanying drawings, there are numerous changes and modification that could be made by one skilled in the art. 
     For example, the right and left arched support member or reinforcing devices may be formed integrally from one piece. On the other hand, the side face of the reinforcing device may be extended forward to the front of the front support portion or backward to the back of the rear support portion. 
     It is understood that the embodiments described herein are merely exemplary and that a person skilled in the art may make many variations and modifications without departing from the spirit and scope of the invention. All such variations and modifications are intended to be included within the scope of the invention.