GB1127584A - A rotatably mounted fluid operated linear actuating device - Google Patents

Abstract

1,127,584. Chucks. ERICKSON TOOL CO. 16 May, 1966 [14 March, 1966], No. 21572/66. Heading B3B. In a rotatably mounted fluid operated linear actuating device which may be used to hold a chuck in any selected position despite a loss of fluid actuating pressure, a check valve arrangement is provided which traps fluid in a motor cylinder tending to move the motor piston in one direction so long as there is little or no fluid tending to move the piston in the opposite direction and which allows the trapped fluid to escape when the fluid pressure tending to move the piston in the opposite direction is high. The piston rod 9 of the device is shown connected to the jaws 10 of a chuck 11 of known type for actuation of the jaws 10 into and out of work-gripping position on axial movement of the piston rod 9 in opposite directions. The spindle S which supports the chuck body 12 is attached to the fluid housing 2 of the motor cylinder by a coupling 24 and is driven by a machine tool (not shown). A rotary coupling 28 is mounted on the housing 2, the coupling having ports 28, 29 through which air or other fluid is selectively admitted under pressure to the cylinder 7 to move the piston 8 in opposite directions with the housing 2 and spindle S rotating. One way check valve assemblies 45, 46 are concentrically located respectively in recesses 36, 42 in the housing part 5 and piston rod 8, each check valve consisting of a sleeve 47 having a seat 48 therein and the poppet valve 49 which is yieldably held in engagement with the seat 48 by a spring 50 permitting flow of fluid under pressure from the associated ports 29, 30 into the respective ends of the fluid cylinder 7. A plunger 52 is provided in each check valve assembly, the plunger having a greater effective area than the poppet valve and an extension 53 projecting towards the poppet valve to cause the same to open the associated poppet valve for exhaust of fluid. To move the chuck into workpiece gripping position air or other fluid under pressure is admitted to the rod end of the cylinder through the port 30 and check valve 46 to move the piston 8 to jaw-closing position. At the same time the high pressure produced in the rod end of the cylinder acts on the plunger 50 and check valve assembly via passage 37 and branch passage 55 to open its associated poppet valve 49 for allowing the escape of fluid from the head end of the cylinder 7 through the check valve assembly 45, passage 35 and port 29. Fluid entering the rod end of the cylinder 7 cannot escape through the check valve assembly 46 until high fluid pressure is admitted to the head end of the cylinder 7 to cause the plunger 52 of the check valve assembly 46 to move to a position unseating the associated poppet valve 49. Release of the trapped air is effected by supplying fluid under pressure through the port 29 to the head end of the cylinder 7 via the passage 35, recess 36 and check valve assembly 45.