GB775889A - Improvements in or relating to hydraulic control systems for hydraulic working pistons of machine tools - Google Patents

Abstract

775,889. Grinding. GAUB, H., [trading as JUNG SCHLEIFMASCHINEN H. GAUB]. Aug. 18, 1954 [Feb. 22, 1954], No. 24079/54. Class 60 [Also in Group XXIX] A hydraulic control system for a grinding machine comprises a distributing valve which is controlled by a vane motor, the exhaust from which drives a piston during its working stroke. Pumps P, P<SP>1</SP> supply liquid via pipes 30a, 31a to a distributing valve 34, in a position I of which liquid from both pumps is supplied via a pipe 28a to a vane motor 36, the exhaust from which passes through a conduit 28 to move a piston 19 rapidly to the left. Movement of the piston 19 is transmitted to the cross-slide of an internal grinding machine. The vane motor drives a camshaft through gears 39, 40, a follower 48 co-operating with the cams and being carried by a lever 46 operatively connected to the slide valve. When the vane motor reaches the position shown the valve is brought into a position II by the follower engaging a raised part of a cam 43. Pump P then supplies liquid to the motor 36 to give a slow movement to the piston 19, pump P<SP>1</SP> being connected to exhaust via pipes 37a, 37. Towards the end of the movement the follower engages a cam 42 and the valve is brought into a position III in which pumps P, P<SP>1</SP> supply liquide to move the piston 19 to the right, exhaust liquid driving the vane piston of motor 36 in a clockwise direction. The valve is retained in position III by an abutment 49 engaging the lever 46 until the lever is forced past the abutment by, for example, a connecting red controlled by dogs on the grinding machine table. The cam shaft may carry cams controlling other distributing valves. Specification 774,411 is referred to.