Hydraulically operable linear motor

Claim 1

A hydraulically operable linear motor, which includes: a cylinder having first and second end walls respectively arranged at opposite ends of said cylinder, a double-acting piston reciprocally mounted in said cylinder, a piston rod extending through one of said cylinder end walls and being connected to one side of said piston so as to form on said one side an annular piston surface, first conduit means leading into said cylinder and continuously communicating with said annular piston surface for continuously conveying fluid pressure to said annular piston surface for continuously conveying fluid pressure to said annular piston surface when said first conduit means is connected to a source of fluid pressure, second conduit mEans continuously communicating with the other side of said piston, control valve means interposed between said first and second conduit means and movable to a first position to connect said second conduit means to said first conduit means and also movable to a second position to connect said second conduit means to an exhaust, said control valve means including first surface means in continuous communication with said first conduit means and fluid pressure operable to move said control valve means to said second position, said control valve means also including second fluid operable surface means for moving said control valve means to said first position, and a fluid conveying control conduit system having first line means and second line means respectively leading into said cylinder on opposite sides of said piston when the latter is in a position intermediate its end positions, said control conduit system also having third line means communicating with said second fluid operable surface means and also having fourth line means communicating with said first and second and third line means and leading to an exhaust, and throttle means respectively arranged in said first and second and fourth line means.