Patent ID: 6546725
Filing Date: 2003-04-15
Classification: B66F

Abstract:
A continuously auto lifting and lowering hydraulic jack including a base, an oil pump, a working oil cylinder, a piston, an oil box, an accumulator, a two-position and two-way valve, a dual-controlling check valve, a pressure-set check valve and a plurality of further check valves, further comprising:said two-position and two-way valve, said dual-controlling check valve and said pressure-set check valve are arranged in a straight line; a valve bore is formed in said base, to serve as a common valve bore for said two-position and two-way valve, said dual-controlling check valve and said pressure-set check valve; valve members of said two-position and two-way valve, said dual-controlling check valve and said pressure-set check valve are disposed sequentially in said valve bore in series; a first tappet is positioned between said two-position and two-way valve and said dual-controlling check valve; and a second tappet is positioned between said dual-controlling check valve and said pressure-set check valve.