Footwear midsole comprising a support and one or more internal bladders

Abstract

The disclosed invention is directed to a footwear midsole configured as a rigid support comprising a cavity that includes a plurality of fluid-filled bladders. The bladders are formed from an elastomeric material that allows exclusive top-down compression of the midsole. Accordingly, the midsole provides a reactive opposed rebound force supplied by the elastomeric covering in response to compression. Advantageously, no outsole and/or insole is required, and the midsole can optionally be used alone in a shoe or other item of footwear.

What is claimed is: 
     
         1 . A footwear midsole comprising:
 a rigid support defined by a lower face and a sidewall that extends in an upward direction about a perimeter of lower face, creating a cavity with an open top; and   a plurality of elastomeric fluid-filled bladders positioned within the cavity of the support;   wherein the midsole enables top-down compression when a force is exerted upon the midsole.   
     
     
         2 . The midsole of  claim 1 , wherein each bladder includes an inflation housing that allows fluid to be added or removed from the interior compartment. 
     
     
         3 . The midsole of  claim 1 , wherein the fluid comprises a gas, a liquid, gel, or combinations thereof. 
     
     
         4 . The midsole of  claim 1 , wherein the bladders are attached along adjacent edges to each other. 
     
     
         5 . The midsole of  claim 1 , wherein the fluid is selected from ambient air, helium, carbon dioxide, water, saline, or combinations thereof. 
     
     
         6 . The midsole of  claim 1 , wherein the support is constructed from plastic, wood, carbon fiber, metal, or combinations thereof. 
     
     
         7 . The midsole of  claim 1 , wherein the bladders are constructed from natural or synthetic rubber, natural or synthetic rubber blends, polyisoprene, polybutadiene, chloroprene rubber, butyl rubber, styrene-butadiene rubber, nitrile rubber, silicone, polyether block amides, ethylene-vinyl acetate, thermoplastic elastomers, polyurethane, polyester, polyester polyurethane, polyether polyurethane, or combinations thereof. 
     
     
         8 . The midsole of  claim 1 , wherein the interior compartment of each bladder has a volume of about 10-200 cubic centimeters. 
     
     
         9 . The midsole of  claim 1 , wherein the bladders are permanently attached to the midsole. 
     
     
         10 . The midsole of  claim 1 , wherein the sidewall tapers from a first end of the support to a second end of the support. 
     
     
         11 . The midsole of  claim 10 , wherein the sidewall has a first height at the first end that is about 20 to 90 percent of a second height at the second end. 
     
     
         12 . The midsole of  claim 1 , wherein each bladder is filled to about 40-100 percent capacity. 
     
     
         13 . The midsole of  claim 1 , wherein the fluid within each bladder has a pressure of about 0-350 kPa. 
     
     
         14 . An article of footwear comprising:
 a sole; and   an upper;   wherein the sole comprises a midsole defined by:
 a support defined by a lower face and a sidewall that extends in an upward direction about a perimeter of lower face, creating a cavity; and 
 a plurality of elastomeric fluid-filled bladders positioned within the cavity of the support; 
 wherein the midsole enables top-down compression when a force is exerted upon the midsole. 
   
     
     
         15 . The article of  claim 14 , wherein the sole further comprises an insole and an outsole. 
     
     
         16 . The article of  claim 14 , wherein the sole lacks an insole, outsole, or both. 
     
     
         17 . The article of  claim 14 , wherein the bladders are constructed from natural or synthetic rubber, natural or synthetic rubber blends, polyisoprene, polybutadiene, chloroprene rubber, butyl rubber, styrene-butadiene rubber, nitrile rubber, silicone, polyether block amides, ethylene-vinyl acetate, thermoplastic elastomers, polyurethane, polyester, polyester polyurethane, polyether polyurethane, or combinations thereof. 
     
     
         18 . The article of  claim 14 , wherein the fluid comprises a gas, a liquid, a gel, or combinations thereof. 
     
     
         19 . The article of  claim 14 , wherein the support is constructed from plastic, wood, carbon fiber, metal, or combinations thereof. 
     
     
         20 . The article of  claim 14 , wherein the sidewall tapers from a first end of the midsole to a second end.