Hydraulic drive for machine tool slide - has pump swung by double-acting piston to give fast but smooth reversal of slide motion

摘要

The slide of a machine tool is actuated by a hydraulic cylinder supplied with oil from a pump. The pump is mounted on trunnions which permit it to swing so that it delivers oil alternately to opposite ends of the hydraulic cylinder. The swing of the pump is controlled by a double acting piston. The travel of this piston is limited by a central peg which abuts against blocks. The position of the blocks is adjusted by a screwed rod so that the swing of the pump is controlled to achieve a fast but smooth reversal of the motion of the machine tool slide.