Pneumatic or hydraulic lifting jack - has inflatable envelope lifting shaft mounted inside rigid cylinder which is closed at one end

摘要

A rigid cylinder (1) is closed at the base (11) and contains an inflatable elastic envelope (2). A lifting shaft (3) rests on the upper surface of the envelope so that the envelope surrounds the base of the shaft. As the envelope is inflated the shaft is raised. Cords are moulded into the envelope to limit its travel during inflation. A guide ring (4) mounted at the upper extremity of the cylinder ensures smooth travel of the shaft. The envelope can be inflated by air, water, oil etc.