Footwear midsole comprising an internal bladder

Abstract

The presently disclosed subject matter is directed to a footwear midsole configured as an air-filled bladder formed from one or more exterior walls. The interior of the midsole comprises one or more fluids (e.g., gases or liquids). The midsole further includes a covering that partially or fully covers the interior compartment. The covering is formed form 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.

What is claimed is: 
     
         1 . A footwear midsole comprising:
 an interior compartment comprising a fluid; and   an elastomeric covering spanning at least a portion of an exterior surface of the interior;   wherein the midsole enables top-down compression when a force is exerted upon the midsole.   
     
     
         2 . The midsole of  claim 1 , further comprising 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, or combinations thereof. 
     
     
         4 . The midsole of  claim 1 , wherein the fluid is selected from ambient air, nitrogen, carbon dioxide, helium, or combinations thereof. 
     
     
         5 . The midsole of  claim 1 , wherein the fluid is selected from water, saline, or combinations thereof. 
     
     
         6 . The midsole of  claim 1 , wherein the elastomeric material is selected 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. 
     
     
         7 . The midsole of  claim 1 , wherein the interior compartment has a volume of about 40-200 cubic centimeters. 
     
     
         8 . The midsole of  claim 1 , wherein the covering is releasably attached to the midsole. 
     
     
         9 . The midsole of  claim 1 , wherein the covering is attached to a top surface of the midsole. 
     
     
         10 . The midsole of  claim 1 , wherein the covering creates an air-tight seal around the midsole interior compartment. 
     
     
         11 . The midsole of  claim 1 , wherein the interior compartment includes two or more sub-compartments. 
     
     
         12 . The midsole of  claim 11 , wherein at least one sub-compartment is in fluid communication with at least one other sub-compartment. 
     
     
         13 . The midsole of  claim 1 , wherein the interior compartment is filled to about 40-100 percent capacity. 
     
     
         14 . The midsole of  claim 1 , wherein the fluid within the midsole interior has a pressure of about 0-350 kPa. 
     
     
         15 . An article of footwear comprising:
 a sole; and   an upper;   wherein the sole comprises a midsole defined by:
 an interior compartment comprising a fluid; and 
 an elastomeric covering spanning at least a portion of an exterior surface of the interior; 
   wherein the midsole enables top-down compression when a force is exerted upon the midsole.   
     
     
         16 . The article of  claim 15 , wherein the sole further comprises an insole and an outsole. 
     
     
         17 . The article of  claim 15 , wherein the elastomeric material is selected 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 15 , wherein the fluid comprises a gas, a liquid, or combinations thereof. 
     
     
         19 . The article of  claim 15 , wherein the interior compartment includes two or more sub-compartments. 
     
     
         20 . The article of  claim 15 , wherein the fluid within the midsole interior has a pressure of about 0-350 kPa.