Water cushion and method of using the same

Claim 1

A cushion particularly suited for use in supporting a human body in a seated disposition comprising: a sealed envelope formed of a pair of similarly configured flexible sheets disposed in superimposed registry and having an endless seam extended about the periphery thereof, said envelope being characterized by a first section extended transversely across said envelope for receiving in supporting relation the buttocks of a seated human body and having defined therein a water-filled, unbaffled chamber from which the water is expelled in response to the weight of a seated human body, and a second section of a thickness slightly less than the thickness of the first section extended transversely across the envelope in juxtaposed parallelism with the first section for receiving water expelled from said unbaffled chamber including support means for supporting the second section against deformation about axes lying in the plane thereof comprising, an array of at least six tubular chambers of uniform cylindrical configurations normally related to the first chamber and extended in juxtaposed parallelism, each having an open end communication with said first chamber for receiving water expelled therefrom and a sealed end opposite said open end for confining the expelled water under pressure, whereby the tubular chambers are adapted to become substantially rigid in response to the weight of the seated body, and means including a sealable port for introducing into said unbaffled chamber water of a quantity sufficient for imparting rigidity to said tubular chambers as the water is expelled from said unbaffled chamber in response to the weight of a human body as the buttocks thereof are received by said first section of said envelope.