Device for prestressing a pressing frame of presses for massive forming, for example extruding presses or forging presses

摘要

A prestressed pressing frame is composed in general of a cylinder beam, a counterbeam and pulling and pressing elements which connect the latter. The pulling elements may take the form of columns or as stacks of pulling plates and the pressing elements may take the form of pressing sleeves or pressing boxes which enclose the said plates between the cylinder beam and the counterbeam. The columns are supported via column nuts and/or the pulling plates are supported via hammer heads on the outsides of the end faces of the beams. Spacers are provided to maintain the prestressing. As all the available pressing cylinders would have to be overloaded by means of additional bolts between the cylinder beam and the counterbeam at 1.35 times operating pressure if the pulling elements were to be prestressed repeatedly, a simple prestressing device is provided here which is built into the press. Pistons slide in bores which are provided as high pressure cylinders on the outside of the end face of the counterbeam parallel to the pressing axis, which pistons are supported either on the underside of the column nuts or beneath the hammer heads. A small hydraulic high-pressure pump is used to subject the high pressure cylinders to high pressure via corresponding valves.