Sole structure for article of footwear

Abstract

An article of footwear includes an upper and a sole structure coupled with the upper. The sole structure includes a midsole that is coupled to the upper along an upper surface of the midsole and to an outsole along a lower surface that is opposite the upper surface. Both the upper surface and the lower surface are curved along a width of the sole structure to curve away from the upper and toward the outsole within a forefoot region, thus forming a rounded surface that extends throughout the forefoot region. A stiffening member is coupled to the midsole and extends from a heel end toward a toe end. The stiffening member includes a base disposed within at least a midfoot region and a plurality of tines that extend into the forefoot region from the base.

We claim: 
     
         1 . A sole structure for an article of footwear having an upper, the sole structure comprising
 a midsole that is coupled to the upper along an upper surface of the midsole and to an outsole along a lower surface that is opposite the upper surface, both the upper surface and the lower surface being curved along a width of the sole structure to curve away from the upper and toward the outsole within a forefoot region; and   a stiffening member coupled to the midsole and extending from a heel end toward a toe end, the stiffening member including a base disposed within at least a midfoot region and a plurality of tines extending into the forefoot region from the base.   
     
     
         2 . The sole structure of  claim 1 , wherein, along the width of the sole structure, the upper surface defines a first curvature and the lower surface defines a second curvature. 
     
     
         3 . The sole structure of  claim 2 , wherein the first curvature is different from the second curvature so that the midsole has a crescent-like cross-sectional shape taken perpendicular to a longitudinal axis of the sole structure. 
     
     
         4 . The sole structure of  claim 2 , wherein the first curvature defines a first radius of curvature and the second curvature defines a second radius of curvature that is smaller than the first radius of curvature. 
     
     
         5 . The sole structure of  claim 1 , wherein the lower surface is curved to have an ellipsoidal shape in the forefoot region. 
     
     
         6 . The sole structure of  claim 5 , wherein the ellipsoidal shape is a hemispherical shape. 
     
     
         7 . The sole structure of  claim 5 , further comprising a plurality of ground engaging elements extending radially outward from the lower surface in the forefoot region. 
     
     
         8 . The sole structure of  claim 1 , wherein the midsole includes a first midsole portion that is disposed in the forefoot region and a second midsole portion that is disposed in a heel region of the sole structure. 
     
     
         9 . The sole structure of  claim 8 , wherein the first midsole portion and the second midsole portion are spaced apart from one another by a gap in the midfoot region. 
     
     
         10 . The sole structure of  claim 9 , wherein the stiffening member bridges the gap between the first midsole portion and the second midsole portion. 
     
     
         11 . The sole structure of  claim 1 , wherein the plurality of tines includes a first tine extending along a lateral side of the sole structure and a second tine extending along a medial side of the sole structure. 
     
     
         12 . The sole structure of  claim 11 , wherein the plurality of tines further includes a third tine that is positioned between the first tine and the second tine, the third tine extending along a longitudinal axis of the sole structure. 
     
     
         13 . The sole structure of  claim 1 , wherein the base of the stiffening member extends into a heel region of the sole structure. 
     
     
         14 . The sole structure of  claim 1 , wherein the plurality of tines are disposed within the midsole in the forefoot region. 
     
     
         15 . The sole structure of  claim 14 , wherein the midsole includes an upper midsole layer defining the upper surface and a lower midsole layer defining the lower surface, and
 wherein the plurality of tines are disposed between the upper midsole layer and the lower midsole layer.   
     
     
         16 . The sole structure of  claim 15 , wherein the base of the stiffening member extends along the upper surface in the midfoot region. 
     
     
         17 . A sole structure for an article of footwear having an upper, the sole structure comprising:
 a midsole defining an upper surface configured to couple to the upper and a lower surface opposite the upper surface, the lower surface being curved in a forefoot region of the sole structure so that the lower surface has an ellipsoidal shape; and   a stiffening member having a plurality of tines that extend from a base, the plurality of tines extending in a heel-to-toe direction within the forefoot region and including at least a first tine extending along a first curvature along a lateral side of the midsole to provide the lateral side of the midsole with a first stiffness and a second tine extending along a second curvature along a medial side of the midsole to provide the medial side of the midsole with a second stiffness.   
     
     
         18 . The sole structure of  claim 17 , wherein the midsole has a crescent-like cross-sectional shape taken perpendicular to a longitudinal axis of the sole structure, such that the midsole is thickest proximate the longitudinal axis and gradually thins moving outward toward each of a medial side and a lateral side of the sole structure. 
     
     
         19 . The sole structure of  claim 18 , further comprising an outsole that is coupled to the lower surface of the midsole to provide a ground engaging surface, the outsole conforming with the shape of the lower surface. 
     
     
         20 . A sole structure for an article of footwear having an upper, the sole structure comprising:
 a midsole that is configured to couple to the upper along an upper surface of the midsole and to an outsole along a lower surface that is opposite the upper surface, the lower surface being curved along both of a width and a length of the sole structure to form a continuously rounded and convex surface that extends throughout a forefoot region of the sole structure, and   a stiffening member coupled to the midsole, the stiffening member having a plurality of tines that extend from a base, the plurality of tines extending in a heel-to-toe direction within the forefoot region and including at least a first tine extending along a first curvature along a lateral side of the midsole to provide the lateral side of the midsole with a first stiffness and a second tine extending along a second curvature along a medial side of the midsole to provide the medial side of the midsole with a second stiffness.