Drive for shifting the stroke position of forming machines

摘要

A method of controlling the drive of a forming machine, in particular of a hydraulic press or hydraulically driven forging machine, having at least one pump cylinder actuated by a crank-type driving mechanism and having return cylinders subjected to constantly rechargeable accumulator pressure, makes simple stroke position shifting and longer overall strokes possible by shutting off the supply of pressure medium to the return cylinders after a working stroke, whereby the return stroke is prevented from occurring and pressure fluid is sucked from the low pressure container into the working cylinder of the forming machine, and only turning the supply of pressure medium to the return cylinders on again for a new working stroke. In a drive of a forming machine the working cylinder of the forming machine is connected to the pump cylinder through a line that is connected via a first controlled check valve to a low pressure container, and a second controlled check valve is fitted in a line connecting the return cylinders with the fluid accumulator or the low pressure container.