For the internal high-pressure forming press and / or external hydroforming

摘要

The sheet holder (4) is designed so that it can be coupled to and decoupled from the ram (3). After a closure stroke, the sheet holder and the ram can be rigidly secured by a mechanical lock (6, 5). The method for operating the press includes the following features: a) the no-load stroke and beginning of the working stroke are effected by the relatively small ram cylinder; b) locking of the sheet holder and the ram takes place when the bottom dead centre is reached; c) after locking of the sheet holder, different holding down pressures are produced by the cylinders (4); d) after the lowest position is reached, the ram is locked by the locking device (5); e) as soon as the sheet holder rigidly rests on the cylinders (4), the working cylinders (9) take over the function of these cylinders and provide an additional closure force.