Patent ID: 7517294

Claim:
A dual-bladder inflatable ball comprising: a valve unit; an outer cover defining a confining chamber therein and connected sealingly to said valve unit; a bladder unit enclosed in said confining chamber in said outer cover, connected to said valve unit, and including an inner bladder and an outer bladder enclosing said inner bladder and disposed between said outer cover and said inner bladder, said bladder unit being operable between an inflated state, where said inner and outer bladders are spherical in shape and said inner bladder abuts against said outer bladder, and a deflated state, where said inner and outer bladders are non-spherical in shape and cooperatively define a gap therebetween, said outer bladder having a first elongation percentage, said inner bladder having a second elongation percentage greater than said first elongation percentage of said outer bladder; wherein said valve unit includes a slit-type valve, each of said outer cover and said inner and outer bladders being formed with a hole for extension of said slit-type valve therethrough, said valve unit further including a hollow valve-supporting seat and a hollow valve-retaining member extending fittingly into said valve-supporting seat, said slit-type valve extending fittingly into said valve retaining member, each of said valve-supporting seat and said valve-retaining member having a rim portion extending outwardly therefrom and secured to a periphery of said hole in a respective one of said inner and outer bladders; and wherein said valve-supporting seat is made from a material having a third elongation percentage, said valve-retaining member made from a material having a fourth elongation percentage smaller than said third elongation percentage of said valve-supporting seat.