Pneumatic hydraulic car lifting jack - has non return safety piston controlled by four way three direction valve

摘要

The pneumatic lifting jack has a safety non return - feature. It has two telescopic hydraulic pistons (1, 2) moving inside the pneumatic jack (3) under control of a non return valve (4) and a four way, three direction valve (5). The upper hydraulic piston (1) is joined to the upper pneumatic piston (6). At the jack base is a liquid reservoir (7). The chamber (2') is fixed to the jack base and connected to the reservoir by a pipe (8) closed by the non return valve (4). The valve has a non return valve (9) acted on (11) by a pilot piston (10) actuated by the valve (5).