Abstract: A hydraulic device is described which operates with an open hydraulic circuit. The device includes a positive-displacement pump for driving hydraulic fluid. An actuation motor having a flywheel is attached to the positive-displacement pump. A tank for hydraulic liquid is connected via a delivery line to the pump. The pump capable of directing hydraulic fluid flow either towards the tank or towards a hydraulic actuation means. The control of flow direction is determined by a first directional control valve means which is connected on the output side of the pump in order to discharge the flow of the positive displacement pump either to the tank or to the hydraulic actuation means. A method for pressing bodies to be processed is also described.