Hydraulic blank holder for single-acting presses

摘要

The aim is, in the case of single-acting presses, to generate large blank-holding forces with little energy expenditure, while maintaining the die-cushion functioning. The object is to achieve, during the drawing operation of a single-acting press, clamping of the workpiece against the ram and hence the blank-holding, without the ram having to work against this force. This is achieved according to the invention in that the press ram (3) and the thrust-bolt plate (10) are actively connected via at least two working cylinders (11) in such a way that the thrust-bolt plate (10) is actively connected via a connecting element (14) to a crossmember (13), on which the piston rod (12) of the respective working cylinder (11) is articulated, the same being fixedly connected to one end of the associated connecting rod (7), while the other end of the connecting rod (7) is arranged on the press ram (3), and in that a piston (15) is arranged underneath the thrust-bolt plate (10), which piston is fixedly connected to the same and is guided in a pneumatic cylinder (16). <IMAGE>