Pump-valve unit for hydraulic jack - has oil flow between reservoir and pump cylinder controlled by valve consisting of elastic band covering port in circumferential recess at end of cylinder

摘要

The valve element of the first valve port (13) consists of an elastic band (10) seated in a circumferential recess (22). The valve element of the second valve port (30) is a headed, spring-loaded pin (11) forming a non-return valve. On the downward working stroke of the piston (7) the elastic ring (10) is pressed outwards, closing the port (13). On the upward stroke the elastic ring is pressed inwards, allowing oil to fill the pump cylinder. ADVANTAGE - Compact design with small radial dimension. Easy to produce.