GB868220A - Improvements in or relating to surface grinders - Google Patents

Abstract

868,220. Grinding. ELLIOTT & CO. Ltd., B. March 7, 1960 [Dec. 8, 1958], No. 39468/58. Class 60. A surface grinding machine comprises a grinding wheel 2 adapted to grind the surface of a workpiece mounted on a work-table d movable to-and-fro relative to a saddle b which, in turn, is movable to-and-fro relative to a base 4 at right angles to the movement of the work-table, and a control system whereby either both the saddle and work-table are reciprocated to effect criss-cross grinding, or one part, for example, the work-table, is reciprocated while the other part, the saddle, is moved step-by-step unidirectionally. The grinding wheel is belt or chain driven from an electric motor 9 and is carried by a slide 3 vertically-adjustable relative to the base 4. The saddle b is movable relative to the base by a piston-and-cylinder device, the cylinder a being secured to the saddle and the rod of the piston a<SP>1</SP> being secured to the base. A piston c<SP>2</SP> is secured to the saddle and is disposed in a cylinder C secured to the work-table to reciprocate the latter relative to the saddle. The alternate ends of the work-table cylinder are supplied with hydraulic pressure from a pump f under the control of a reversing valve c<SP>1</SP> actuated at the end of each stroke, or each alternate stroke, of the table by pressure supplied to alternate ports i<SP>1</SP>, i2 by the movement of a valve h actuated by dogs on the work-table. A control valve j, adjustable throttle valve l and pressure relief valve k are incorporated in the work-table circuit The saddle cylinder a is supplied with hydraulic pressure from a circuit having a pump e and a valve n which, in the position shown, directs the fluid from a control valve m to a valve o reversible at the end of each stroke of the saddle by dogs on the saddle to supply fluid to the alternate ends of the cylinder a. When the valve n is moved to its alternative position, the supply from the pump e is directed to a valve q which is movable to alternate positions where the valve h is actuated to reverse the valve i and the direction of movement of the work-table, and supplies fluid to the alternate ends of a metering valve r. Each time the valve q is actuated, a piston r<SP>1</SP> of the metering valve permits a small quantity of fluid to be supplied to the cylinder a to provide the step-by-step movement of the saddle, the amount of fluid supplied being determined by an adjustable stop r<SP>4</SP>. When the saddle has reached the end of its stroke, the valve o is actuated to reverse the direction of the step-by-step movements. In other embodiments the metering valve is actuated mechanically each time the work-table reaches the end of its stroke, and hydraulic paddle motors may replace the work-table and saddle piston-andcylinder devices.