Sole for a shoe

Abstract

In the stable posture, in which path length from the origin to the distal end is L, intersection between the sole bottom surface and line perpendicular to the reference line through position of 0.45×L is C, intersection between the sole bottom surface and line perpendicular to the reference line through position of 0.60×L is D, and sole is in contact with the ground at points C and D, the sole bottom surface at the heel portion is separated from the ground to be in a heel-up state, and an inequality, θ≥5 is satisfied wherein θ is an angle formed by the ground and line that connects the heel central position of 0.15×L with the metatarsophalangeal joints position of 0.68×L. The sole compressive rigidity is relatively lower at the heel-up starting position than at the metatarsophalangeal joints position.

What is claimed is: 
     
         1 . A sole for a shoe, said sole extending from a heel region through a midfoot region to a forefoot region and having a sole upper surface and a sole lower surface,
 wherein a sole stable posture is proposed in which a line that connects a rearmost end position of said sole upper surface with a distal end position of a toe is defined as a reference line S, said rearmost end position is defined as an origin O, a path length measured along said sole upper surface from the origin O to said distal end position of said toe is defined as L, an intersection point between said sole lower surface and a line perpendicular to said reference line S through a position of 0.45×L from the origin O along said sole upper surface is defined as C, an intersection point between said sole lower surface and a line perpendicular to said reference line S through a position of 0.60×L from the origin O along said sole upper surface is defined as D, and said sole is in contact with the ground at said points C and D,   wherein in said sole stable posture, said sole lower surface is separated from the ground at a toe portion and said sole lower surface is separated from the ground at said heel region to be in a heel-up state,   wherein in said sole stable posture, an inequality, θ≥5 [degrees] is satisfied in which said angle θ is defined as an angle formed between the ground and a line connecting a heel central position of 0.15×L from the origin O along said sole upper surface and a metatarsophalangeal joints position of 0.68×L from the origin O along said sole upper surface,   wherein a sole compressive rigidity in an up-and-down direction is relatively lower at a heel-up starting position of said heel region than at said metatarsophalangeal joints position.   
     
     
         2 . The sole according to  claim 1 , wherein in said sole stable posture, said sole lower surface is separated from the ground in a rearward region that extends rearward from the position of 0.15×L from the origin O along said sole upper surface, said sole lower surface is separated from the ground in a forward region that extends forward from the position of 0.68×L from the origin O along said sole upper surface, and said sole lower surface is in contact with the ground in a forward region that extends forward from the position of 0.15×L from the origin O along said sole upper surface and in a rearward region that extends rearward from the position of 0.68×L from the origin O along said sole upper surface. 
     
     
         3 . The sole according to  claim 1 , wherein said heel-up starting position is disposed at a backside of an ankle position of 0.27×L from the origin O along said sole upper surface. 
     
     
         4 . The sole according to  claim 1 , wherein in said sole stable posture, in a static upright posture when a shoe is worn by a wearer, said sole compressive rigidity is determined such that θ<5 [degrees] is satisfied. 
     
     
         5 . The sole according to  claim 1 , wherein said heel region has an aperture and said forefoot region does not have an aperture. 
     
     
         6 . The sole according to  claim 1 , wherein said heel region and said forefoot region have an aperture and an open width of said aperture at said heel region is greater that an open width of said aperture at said forefoot region. 
     
     
         7 . The sole according to  claim 1 , wherein said heel region and said forefoot region have an aperture and an aperture ratio at said heel region is greater that an aperture ratio at said forefoot region. 
     
     
         8 . The sole according to  claim 1 , wherein said heel region is formed by a material of relatively lower hardness and said forefoot region is formed by a material of relatively higher hardness. 
     
     
         9 . The sole according to  claim 1 , wherein both said heel region and said forefoot region have a material area of relatively lower hardness and another material area of relatively higher hardness, and an occupancy ratio of said material area of relatively lower hardness at said heel region is set at a relatively high value and an occupancy ratio of said material area of relatively higher hardness at said forefoot region is set at a relatively high value. 
     
     
         10 . The sole according to  claim 1 , wherein said points C and D are disposed at least at a lateral side edge portion of said sole lower surface. 
     
     
         11 . The sole according to  claim 1 , wherein a region extending from said point C to said point D of said sole lower surface constitutes a stable region formed of a flat-shape, and in said sole stable posture, said stable region is in contact with the ground.