Sole Structure for a Shoe

Abstract

The sole structure 1 has an upper plate, a lower midsole located under and fixedly attached to the upper plate, and having a laterally extending groove opening to the bottom side of the lower midsole, and a bending restriction member formed in a bent shape and spanning the groove longitudinally between the front edge and the rear edge of the opening of the groove. During the beginning phase of sole bending, the bending restriction member allows for the sole to bend till the bending restriction member gradually extends toward a straight shape from the bent shape and becomes taut between the front edge and the rear edge of the opening of the groove. During the advanced phase of the sole bending, when the bending restriction member experiences a force from the taut state, it functions so as to restrict the sole from bending.

1 . A sole structure for a shoe comprising:
 a sole having a laterally extending groove, said groove being formed on a bottom surface of said sole;   and a bending restriction member formed in a bent shape and spanning said groove longitudinally between a front edge and a rear edge of an opening of said groove,   wherein during a beginning phase of bending of said sole, said bending restriction member allows for said sole to bend till said bending restriction member gradually extends toward a straight shape from a bent shape and becomes taut between said front edge and said rear edge of said opening of said groove, and during an advanced phase of bending of said sole, when said bending restriction member experiences a force that pulls said bending restriction member in a longitudinal direction from its taut state, it functions so as to restrict said sole from bending.   
     
     
         2 . The sole structure according to  claim 1 , wherein said groove is disposed at a forefoot region of said sole. 
     
     
         3 . The sole structure according to  claim 1 , wherein said bending restriction member has an upwardly protruded bent portion in said groove. 
     
     
         4 . The sole structure according to  claim 3 , wherein said bending restriction member is not fixedly attached to a wall surface of said groove. 
     
     
         5 . The sole structure according to  claim 3 , wherein said bending restriction member is located away from a wall surface of said groove. 
     
     
         6 . The sole structure according to  claim 1 , wherein said bending restriction member has a downwardly protruded bent portion in said groove. 
     
     
         7 . (canceled) 
     
     
         8 . The sole structure according to  claim 1 , wherein said bending restriction member has a sideway protruded bent portion in said groove. 
     
     
         9 . The sole structure according to  claim 8 , wherein said bending restriction member is wire-shaped. 
     
     
         10 . The sole structure according to  claim 1 , wherein said bending restriction member is made of fabric. 
     
     
         11 . The sole structure according to  claim 10 , wherein said bending restriction member is a sheet-shaped member that covers a ground contact side surface of said sole, said sheet-shaped member has a plurality of outsole pieces fixedly attached on a ground contact side surface of said sheet-shaped member. 
     
     
         12 . The sole structure according to  claim 1 , wherein said bending restriction member is located on a medial side or a lateral side of said sole. 
     
     
         13 . The sole structure according to  claim 1 , wherein said bending restriction member is located on a medial side and a lateral side of said sole. 
     
     
         14 . The sole structure according to  claim 1 , wherein an elastic cover member is disposed between said front edge and said rear edge of said opening of said groove, said cover member extends longitudinally along said bent shape of said bending restriction member and covers said bending restriction member from below. 
     
     
         15 . The sole structure according to  claim 14 , wherein an outsole member having a ground contact surface is disposed on a bottom surface of said sole, said cover member being formed of said outsole member. 
     
     
         16 . The sole structure according to  claim 1  further comprising a longitudinally extending upper plate disposed on an upper side of said sole and a midsole formed of a soft elastic material and disposed under said upper plate, said groove being formed on a bottom surface of said midsole. 
     
     
         17 . The sole structure according to  claim 16  further comprising a longitudinally extending lower plate disposed on a lower side of said midsole, said bending restriction member being formed of said lower plate that extends beyond said groove. 
     
     
         18 . A sole structure for a shoe comprising:
 a longitudinally extending plate disposed on an upper side of a sole;   a midsole that is formed of a soft elastic material, that is disposed under and fixedly attached to said plate and that has a laterally extending groove formed on a bottom surface of said midsole;   and a bending restriction member formed in a bent shape and spanning said groove longitudinally between a front edge and a rear edge of an opening of said groove,   wherein during a beginning phase of bending of said sole, said bending restriction member allows for said sole to bend till said bending restriction member gradually extends toward a straight shape from a bent shape and becomes taut between said front edge and said rear edge of said opening of said groove, and during an advanced phase of bending of said sole, when said bending restriction member experiences a force that pulls said bending restriction member in a longitudinal direction from its taut state, it functions so as to restrain said sole from bending.   
     
     
         19 . The sole structure according to  claim 18 , wherein a length L of the bending restriction member along the bent shape thereof between said front edge and said rear edge of said opening of said groove satisfies an inequality,
     S+D ×sin 15 °≦L≦S+H ×sin 15°
   in which S designates a distance between said front edge and said rear edge of said opening of said groove; D designates a depth of said groove; and H designates a thickness of said midsole above a bottom of said groove.   
     
     
         20 - 21 . (canceled) 
     
     
         22 . The sole structure according to  claim 18 , wherein said bending restriction member is formed of a material that has the Young's modulus of 400 MPa or more at a strain of 10% or less. 
     
     
         23 . The sole structure according to  claim 18 , wherein said bending restriction member functions such that it allows for said sole to bend till the bent angle becomes 15° and restricts bending of said sole when the bent angle exceeds 15°. 
     
     
         24 . The sole structure according to  claim 1 , wherein said bending restriction member is formed of a material that has the Young's modulus of 400 MPa or more at a strain of 10% or less. 
     
     
         25 . The sole structure according to  claim 1 , wherein said bending restriction member functions such that it allows for said sole to bend till the bent angle becomes 15° and restricts bending of said sole when the bent angle exceeds 15°. 
     
     
         26 . The sole structure according to  claim 3 , wherein said bending restriction member is band-shaped. 
     
     
         27 . The sole structure according to  claim 6 , wherein said bending restriction member is band-shaped.