3 Fundamentals of press design

84 Fundamentals of press design
lockingcylinder
Fig. 3.3.8 Positive acting slide locking device
prevent the slide from dropping under its own weight when the control
system is switched off. The locking device at the top dead center (TDC) is a
positive-acting locking device at the upper point of the nominal stroke.
A bolt guided in the press frame is pushed by a hydraulic piston into a
recess in the slide (Fig. 3.3.8). The bolt is configured to carry all moving
weights, including that of the die superstructure.
The infinitely variable locking device is a non-positive acting slide safeguard
in which a retaining rod at the slide is guided by the clamping
head in the press crown (Fig. 3.3.9). The pilot jaws hold the movable
elements in any position – even in case of a power failure. This locking
device, which is arranged in the slide area, is recommended particularly
in presses featuring a blank holder and internal slide. The slide can be
fixed in any position, eliminating the need for a separate safety device
for the blank holder.
Metal Forming Handbook / Schuler (c) Springer-Verlag Berlin Heidelberg 1998
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