Hydraulic oil winch

Claim 1

A hydraulic fluid winch comprising a hydraulic fluid pump, a rotatable winch drum, a hydraulic fluid motor for driving said winch drum, a change-over valve, a fluid feed pipe connecting said change-over valve to said pump, a first fluid conduit connecting said change-over valve to said fluid motor for effecting rotation of said winch drum in one direction by said fluid motor and a second fluid conduit connecting said changeover valve to said fluid motor for effecting rotation of said winch drum in a direction opposite to said one direction by said fluid motor, said hydraulic fluid motor having a driving shaft, a one-way clutch connected to said driving shaft, a ratchet wheel mounted through said one-way clutch on said driving shaft, a lock pawl movable into and out of engagement with said ratchet wheel, a hydraulic fluid actuating mechanism for moving said lock pawl, said mechanism including a hydraulic cylinder having a fluid inlet in communication with said second fluid conduit and a fluid outlet, spaced from said inlet, a piston slidably carried in said cylinder, means for constantly urging said piston along said cylinder toward said fluid inlet, abutment means for stopping movement of said piston in the direction of said fluid outlet, a piston rod having one end located exteriorly of said cylinder connected to said lock pawl and its other end extending within said cylinder and said piston rod being movable relative to said cylinder, said piston rod having fluid passage means and said piston being carried on said piston rod and movable relative to said piston rod between a first position wherein said fluid passage means is open so that fluid flow from said inlet to said outlet is permitted and a second position wherein said fluid passage means is closed by said piston.