Press with hydraulic overload safety device and ram weight counterbalancing mechanism

摘要

A press having mechanical drive elements acting on the ram through at least one pressure cushion serving as a hydraulic overload safety device, at least one cylinder-piston unit operating under the effect of a compressed fluid for counterbalancing the weight of the ram associated with an upper die of the press, and a control system for adjusting fluid pressure in the cylinder-piston unit to a value for counterbalancing the weight. The control system includes a pressure relief valve and a pressure meter associated with the pressure cushion wherein the meter detects the pressure in the pressure cushion in a measuring range including a predetermined value. An actuating member serves for initiating a counterbalancing operation which includes operation of the pressure relief valve and control of supply and discharge valves for supplying and discharging fluid to and/or from the cylinder-piston unit.