Double-acting hydraulic exerciser

Claim 1

A double-acting hydraulic exerciser which in operation is even and free of strain in both tension and traction, said exerciser comprising: A. inner and outer tubes in telescoping relationship, the inner tube defining a chamber which is oil-filled and encloses a piston, said inner tube having a storage cavity surrounding said chamber and a valve interposed between the chamber and the cavity to allow oil to pass in both directions, said tubes being formed of relatively light weight material incapable of supporting loads substantially beyond that imposed by a human user and having lengths such that when the tubes are fully extended, the distance between handles attached to the ends thereof is substantially equal to the distance between the outstretched hands of a typical user; B. a piston rod extending between said piston and the end of said outer tube, said piston dividing said chamber into right and left sections and being provided with valves that function alternately to allow oil to pass from the right section to the left section when the tubes are brought together in a compression stroke, and to allow oil to pass from the left section to the right section when the tubes are pulled apart in an expansion stroke, the compression and expansion strokes being linear throughout their lengths; and C. a pair of hand-grippable handles attached to the ends of said tubes whereby said strokes may be effected manually by said user.