Hydraulic jack
This device is a continuously auto lifting and lowering hydraulic jack which can accomplish continuously and automatically lifting and lowering cycles without the help of an external force.a hydraulic circuit is simplified by the arrangement of controlling valves to achieve a reliable and convenient control.
A hydraulic jack uses a fluid, which is incompressible, that is forced into a cylinder by a pump plunger. Oil can be used as it is self lubricating and stable. oil is drawn out of the reservoir through a suction check valve into the pump chamber When the plunger pulls back. When the plunger moves forward, it pushes the oil through a discharge check valve into the cylinder. with each draw of the plunger, the suction valve ball within the chamber opens. The discharge valve ball is outside the chamber and opens when the oil is pushed into the cylinder.the chamber is forced shut at this point and the oil pressure builds in the cylinder.
Hydraulic jack and a hydraulic circuit
The device consists of a base, an oil pump, working oil cylinder, a piston, an oil box, an accumulator, a two-position and two-way valve, a dual-controlling check, a pressure-set check and other checks. the dual-controlling check , The two-position and two-way valve, and the pressure-set check are arranged in a straight line. a tappet is positioned between the two-position and two-way valve and the dual-controlling check
for full details and drawings, visit this link:
http://patentstorm.us/patents/6546725/fulltext.html
http://en.wikipediawiki/Hydraulic_jack