Cushioning device for a footwear sole and method for making the same

An article of footwear comprising an upper and a sole;

• said sole including a bladder composite;
• said bladder composite comprising:
• an outer bladder containing a cushioning and supportive fluid;
• an inner bladder containing a cushioning and supportive fluid, said inner bladder including a plurality of chambers in fluid communication and having a plurality of surface depressions between adjacent said chambers, said inner bladder being completely encased within said outer bladder and said cushioning and supportive fluid in said outer bladder filling said plurality of surface depressions such that a generally smooth upper and lower surface is obtained;
• wherein said inner bladder and said outer bladder are sealingly connected to define a common perimeter seal for said bladder composite and said bladder composite is capable of withstanding concentrated and repetitive high impact loads occurring with footstrike.

A method of forming an article of footwear having a cushioning element comprising the steps of:

• forming an upper and a sole;
• forming a first bladder from an elastomeric material to form an interior cavity within a perimeter of the bladder and providing at least one depression in at least one of a top and bottom surface of the first bladder to constrain expansion;
• forming a second bladder from an elastomeric material around said first formed bladder to thereby encase said first bladder within said second bladder;
• inflating the first bladder with a first medium;
• and
• overlapping and sealing a perimeter of said second bladder around the perimeter of said first bladder and thereby preventing movement of said first bladder within said second bladder;
• placing said bladders within said sole;
• wherein the cushioning element is capable of withstanding concentrated and repetitive high impact loads occurring with footstrike.