Abstract: In a process for operating a press unit comprising a press, more particularly a forging press, having a hydraulic driving and control system that causes the working stroke movement of the press to follow a substantially sinusoidal course, and at least one integrated forging manipulator, synchronization of the working stroke of the press and the stroke of the tong arm of the manipulator is effected by a driving and control system of the forging manipulator by which a stroke movement of the tong arm of the forging manipulator adjusted to match the working stroke of the press and having the same frequency as that of the working stroke movement of the press, but with a smaller amplitude, is produced. For raising and lowering of the tong arm at least one continuously variable, reversible-flow pump is associated with the forging manipulator.

Abstract: 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.