Expansion chamber devices

Claim 1

An expansion device for converting changes in fluid pressure to displacement of a moving machine part or converting displacement of a moving part to changes in fluid pressure, said device comprising a first flexible expansion chamber wall at least partially defining a first expansion chamber region on one side of it, said wall being curved and having an inner surface, a first rigid member having a convex surface supporting said chamber wall, said wall and said convex surface having almost the same shape, a second rigid member having a first concave surface facing said convex surface, and being connected around its periphery to said first flexible wall, means for mounting said first rigid member for pivotal movement toward and away from said second rigid member about an axis to cause, when said first and second rigid members move toward each other, said wall to fold over so that a portion of said wall's inner surface changes from an expanded concave shape spaced from said first member to a contracted convex shape adjacent to said first member, said wall reversing its curvature without harmful stretch or distortion, and said flexible wall being substantially spaced from said first concave surface of said second rigid member when said first rigid member is spaced from said second rigid member in an expanded position, said flexible wall being moved toward said concave surface to said second rigid member and said first rigid member is moved toward said second rigid member, a first displacement connector attached to one of said rigid members.