GB928609A - Midstroke locking device - Google Patents

Abstract

928,609. Hydraulic apparatus. LIONEL-PACIFIC Inc. Jan. 10, 1961, No. 1039/61. Class 69 (2). A mid-stroke locking device comprises a piston assembly which is axially movable in a cylinder 1 having ports 12, 13 at opposite ends for the admission of pressure fluid and has a piston 2 having a rod 20 extending from one end of the cylinder, an axial bore 22 in the assembly communicating with the opposite ends of the cylinder, a plunger 5 movable axially in the bore in a first direction by fluid pressure within either end of the cylinder, spring means 50 to move the plunger in a second direction on relief of pressure in the ends of the cylinder, and complemental fixed and movable locking means 14, 3 carried by the cylinder and the piston assembly, respectively, disengageable by fluid-pressure induced movement of the plunger and engageable by the spring pressure movement of the plunger. The locking means consists of a groove 14 in the cylinder wall engageable by radially-movable dogs 3 movable by links 4 connected to the plunger 5. The plunger is normally urged by the spring 50 to a position wherein the dogs are pressed outwardly to engage the groove when aligned therewith. When fluid pressure is supplied through the port 13, the pressure in the right-hand end of the cylinder moves the plunger against the spring 50 to retract the dogs 3 from the groove 14 to permit movement of the piston, the dogs being retained in the retracted position by spring-pressed balls 6. When fluid is supplied to the port 12, the pressure in the left-hand end of the cylinder is communicated by a passage 23 to a face 51a of the plunger which is again moved to retract the plungers from the groove.