Abstract: A method and apparatus for adaptively controlling a hydraulic press comprising a hydraulic drive unit for lifting and lowering a press ram. A piston chamber of the drive unit can be connected to a hydraulic accumulator formed by at least two groups of storage bottles, the connection established by hydraulic pipes that allows an expandable volume, stored in the storage bottles to supply the energy required for the press to perform a working stroke. Different filling pressures can be established in the storage bottles. A hydraulic accumulator can be adjusted to three operating modes, allowing a press controller to automatically analyze utilization and accordingly block individual groups or compartments of storage bottles, transfer the gas between storage bottles during a charging process at the end of the cycle, or adjust individual groups of storage bottles to different pressure levels. Advantageously, these three scenarios entail no waiting or transfer time.

Abstract: A hydraulic press and a method for operating the press in cycles. The aim is to lower energy consumption in a hydraulic press for shaping workpieces and a method thereof. Each cycle has at least one phase in which the storage pressure pS in the accumulator presses hydraulic fluid into a chamber of a hydraulic cylinder in order to move a ram relative to the cylinder, the ram being coupled to the cylinder. In at least one portion of each cycle, a hydraulic pump driven by a motor delivers hydraulic fluid to the accumulator at a charging volume flow rate. The storage pressure pS is adjusted to a reference value PSOLL by setting the speed of the motor to a nominal motor speed nN and to at least one intermediate value nZ, where 0<nZ<nN.