Sole Structure With Bottom-Loaded Compression

Abstract

A sole structure for an article of footwear includes a midsole and an outsole coupled with the midsole. The midsole includes a first compressible material, and a second compressible material that differs from the first compressible material, where a bottom surface of the second compressible material is co-planar with the first compressible material along the bottom surface of the midsole. The outsole includes a ground engaging surface with traction elements extending from the ground engaging surface, and the outsole continuously extends over the first compressible material and the second compressible material.

What is claimed: 
     
         1 . A sole structure for an article of footwear comprising:
 a midsole comprising:   a first compressible material, and a second compressible material that differs from the first compressible material, wherein a bottom surface of the second compressible material is co-planar with the first compressible material along the bottom surface of the midsole; and   an outsole coupled with the bottom surface of the midsole, wherein the outsole includes a ground engaging surface with traction elements extending from the ground engaging surface, and the outsole continuously extends over the first compressible material and the second compressible material.   
     
     
         2 . The sole structure of  claim 1 , wherein:
 the midsole includes a groove located at a heel side location of the sole structure and extending in a direction from a top edge of the midsole to a portion of the bottom surface of the midsole, traversing both a midsole top portion and a midsole bottom portion; and   the outsole includes a groove located at the heel side location of the sole structure and aligned with the corresponding midsole groove.   
     
     
         3 . The sole structure of  claim 1 , wherein the outsole includes an elongated groove located at a heel side location of the sole structure and extending in a direction from a top edge of the outsole to a portion of the bottom surface of the outsole, traversing both an outsole top portion and an outsole bottom portion. 
     
     
         4 . The sole structure of  claim 1 , wherein the midsole includes an elongated groove located at a heel side location of the outsole and extending in a direction from a top edge of the midsole to a portion of the bottom surface of the midsole, traversing both a midsole top portion and a midsole bottom portion. 
     
     
         5 . The sole structure of  claim 1 , wherein the second compressible material has a substantially uniform thickness that is one half to one third a thickness of a corresponding midsole section located directly above the second compressible material. 
     
     
         6 . The sole structure of  claim 1 , wherein the outsole continuously extends over the entire length of the second compressible material and also an entire length of the midsole. 
     
     
         7 . The sole structure of  claim 1 , wherein both the first and second compressible materials comprise ethylene vinyl acetate (EVA). 
     
     
         8 . The sole structure of  claim 1 , wherein exterior sidewall surfaces of the midsole and outsole combine to form an arcuate profile along toe, heel, medial and lateral sides of the sole structure. 
     
     
         9 . The sole structure of  claim 8 , wherein the ground engaging surface of the outsole includes a lower surface portion and a peripheral sidewall portion, and the traction elements are disposed along the ground engaging surface at the lower surface portion and the peripheral sidewall portion. 
     
     
         10 . The sole structure of  claim 9 , further comprising a plurality of traction zones defined at areas of the ground engaging surface of the outsole, wherein a number of traction elements differs between two or more traction zones. 
     
     
         11 . The sole structure of  claim 10 , wherein the plurality of traction zones comprises a central traction zone located centrally along the lower surface portion of the ground engaging surface, a lateral traction zone located along a lateral side of the ground engaging surface, a medial traction zone located along a medial side of the ground engaging surface, a forward traction zone located along a forefoot region of the ground engaging surface, and a rearward traction zone located along a hindfoot region of the ground engaging surface, and each of the forward and rearward traction zones includes more traction elements than any of the other traction zones. 
     
     
         12 . The sole structure of  claim 11 , wherein traction elements of the central traction zone have a lengthwise dimension h 1  extending from the ground engaging surface of the outsole that is less than a lengthwise dimension h 2  of traction elements of all other traction zones. 
     
     
         13 . A method of forming a sole structure for an article of footwear, the method comprising:
 obtaining a midsole including a midsole groove located at a heel side location of the midsole and extending in a direction from a top edge of the midsole to a midsole bottom;   positioning an insert within the midsole such that a bottom surface of the insert is co-planar with the bottom surface of the midsole;   obtaining an outsole including a ground engaging surface with traction elements extending from the ground engaging surface, and an outsole groove located at a heel side location of the outsole; and   combining the midsole with the outsole such that the insert is disposed between the midsole and the outsole, at least a portion of the outsole continuously extends over an entire length of the insert and also over at least a portion of the bottom surface of the midsole, and the outsole groove aligns with and extends over a portion of the midsole groove.   
     
     
         14 . The method of  claim 13 , wherein the insert has a substantially uniform thickness that is one half to one third a thickness of a corresponding midsole section located directly above the insert. 
     
     
         15 . The method of  claim 13 , wherein the outsole includes a concave interior surface, and the midsole is combined with the outsole by securing the midsole against the concave interior surface of the outsole. 
     
     
         16 . The method of forming a sole structure for an article of footwear of  claim 13 , wherein, upon combining the midsole with the outsole, exterior sidewall surfaces of the midsole and outsole combine to form an arcuate profile along toe, heel, medial and lateral sides of the sole structure. 
     
     
         17 . The method of  claim 13 , wherein the ground engaging surface includes a lower surface portion and a peripheral sidewall portion, and the method further comprises:
 positioning traction elements along the ground engaging surface at the lower surface portion and the peripheral sidewall portion.   
     
     
         18 . The method of  claim 17 , wherein the traction elements are positioned at a plurality of traction zones defined at areas of the ground engaging surface of the outsole, and a number of traction elements differs between two or more traction zones. 
     
     
         19 . The method of  claim 18 , wherein the plurality of traction zones comprises a central traction zone located centrally along the lower surface portion of the ground engaging surface, a lateral traction zone located along a lateral side of the ground engaging surface, a medial traction zone located along a medial side of the ground engaging surface, a forward traction zone located along a forefoot region of the ground engaging surface, and a rearward traction zone located along a hindfoot region of the ground engaging surface, and each of the forward and rearward traction zones includes more traction elements than any of the other traction zones. 
     
     
         20 . The method of  claim 13 , wherein the midsole is combined with the outsole such that the outsole continuously extends over the entire length of the insert and also an entire length of the midsole.