Abstract: A mechanical locking outrigger hydraulic jack for an outrigger assembly for use with cranes and the like includes vertically disposed cylindrical fixed and movable members, the fixed member being secured to a vertically disposed external sleeve. A variable extension chamber is defined by the interiors of the fixed and movable members. A variable retraction chamber is defined exteriorly of the fixed member and interiorly of the movable member. Valve means permit selective raising and lowering of the movable member. A locking nut threadedly engages the threaded exterior of the movable member and is engagable with an external surface of the locking sleeve to mechanically lock the movable member in an extended, lowered position.

Abstract: A hydraulic jack comprises a base having a vertically disposed cylindrical member attached thereto. A cylindrical movable member is mounted on the fixed member and is vertically movable relative thereto. The base is provided with passages therethrough which are connected in communicating relation to a source of fluid under pressure, such as a reservoir and pump. The fixed and movable members define a pair of variable chambers, each of which is connected in communicating relation with one of the passages by a restricted orifice to reduce the flow of fluid to and from the chambers. When one of the chambers is pressurized, the movable member is raised and will support a load engaged thereby. When the other chamber is pressurized, the movable member is lowered. Fluid in the chambers is prevented from returning to the reservoir by valve elements. A valve actuator is operated by fluid pressure and selectively opens each passage to permit the return of fluid to the reservoir.