Footwear sole structure

Abstract

A dynamic footwear midsole has an upper layer and a lower layer that are connected by a group of heel slats and a group of forepart slats, each slat being connected at hinge regions to the upper and lower layers. The slats in each group are arranged in generally paralleling planes with the heel slats and forepart slats being arranged to cause one group to collapse as the other group expands. An arch support is provided at the midportion of the upper layer is constructed to enable the upper layer to rock about the arch support.

1 . A footwear midsole comprising:
 an upper layer;   a lower layer;   each of the layers having a heel portion, a midportion and a forepart portion;
 an arch support at the midportion of the upper layer; 
 a plurality of generally planar heel slats extending transversely between and hingedly connected to the heel portions of the upper and lower layers; 
 a plurality of generally planar forepart slats extending transversely between and hingedly connected to the forepart portions of the upper and lower layers; 
 the arch support being of sufficient strength to present greater resistance to heightwise compression than the heel and forepart regions; 
   
     
     
         2 . The midsole as defined in  claim 1  further comprising:
 the heel slats being inclined in an upward and heelward direction; and 
 the forepart slats being inclined in an upward and toeward direction. 
 
     
     
         3 . The midsole as defined in  claim 1  further comprising:
 the upper and lower layers and the slats being formed as a unitary, one-piece structure. 
 
     
     
         4 . The midsole as defined in  claim 2  further comprising:
 the upper and lower layers and the slats being formed as a unitary, one-piece structure. 
 
     
     
         5 . The midsole as defined in  claim 2  further comprising:
 the arch support extending between the most toeward slat of the heelward group and the most heelward slat of the forepart group 
 
     
     
         6 . The midsole as defined in  claim 5  further comprising:
 the most toeward slat of the heel group and the most heelward slat of the forepart group being attached, respectively, to the upper layer at the toeward and heelward regions of the arch support. 
 
     
     
         7 . The midsole as defined in  claim 6  further comprising:
 the most toeward slat of the heel group and the most heelward slat of the forepart group being thicker and having less flexible hinge regions than the other slats. 
 
     
     
         8 . The midsole as defined in  claim 6  wherein the support structure for the arch support further comprises:
 at least one longitudinally and heightwise extending support brace connected between the upper layer and the lower layer and between the most heelward slat of the forepart group and the most toeward slat of the heel group. 
 
     
     
         9 . The midsole as defined in  claim 1  and having a centerline extending between the heel and toe extremities and further comprising:
 the slats extending at a non-perpendicular angle to the centerline with the medial ends of the slats being toeward of the their lateral ends. 
 
     
     
         10 . The midsole as defined in  claim 9  wherein the angle is between about ten and twenty degrees. 
     
     
         11 . The midsole as defined in  claim 2  wherein the slats in each group are arranged in generally paralleling planes. 
     
     
         12 . The midsole as defined in  claim 1  wherein the upper and lower layers and longitudinally spaced slats define a plurality of hollow prism-shaped cells, each being defined by a pair of adjacent slats and a segment of each of the upper and lower layers. 
     
     
         13 . The midsole as defined in  claim 2  wherein the upper layer is sufficiently stiff to enable the upper layer to rock about the region of the arch support in heelward and toeward directions. 
     
     
         14 . The midsole as defined in  claim 12  wherein the upper layer is sufficiently stiff to prevent distortion of the segments of the upper layer in response to rocking of the upper layer about the arch region. 
     
     
         15 . An article of footwear comprising:
 an upper;   a midsole as defined in  claim 1  attached to the upper; and   an outsole attached to the lower layer of the midsole.