Combination of a chamber and a piston, a pump, a motor, a shock absorber and transducer incorporating the combination

A piston-chamber combination comprising an elongate chamber which is bounded by an inner chamber wall and comprising a piston in the chamber to be sealingly movable relative to the chamber at least between first and second longitudinal positions therein, the chamber having cross-sections of different cross-sectional areas at the first and second longitudinal positions and at least substantially continuously differing cross- sectional areas at intermediate longitudinal positions between the first and second longitudinal positions thereof, the cross-sectional area at the first longitudinal position being larger than the cross-sectional area at the second longitudinal position, the piston being designed to adapt itself and maintain sealing with the inner chamber wall at different cross-sectional areas of the chamber during the relative movements of said piston from the first longitudinal position through said intermediate longitudinal positions to the second longitudinal position of the chamber, wherein the piston means comprises:

• a plurality of support members rotatably fastened to a common member, and
• said support members being molded together with an elastically deformable material supported by the plurality of support members with the elastically deformable material providing sealing against the inner wall of the chamber, said plurality of support members being rotatable between a range of angular positions relative to a longitudinal axis of the chamber.