Press system hydraulic drive device - has decompression valves to allow stress relief after pressing to occur more rapidly

摘要

The hydraulic drive system for a press device (4) has one or more steplessly variable pumps (1). The pumps may be conventionally controlled through the zero transport or flow position in opposite transport direction. Decompression valves (5) or a single decompression valve are attached in parallel across the drive pumps. The decompression valves allow the relief of stress in the working cylinder to be carried out in a more rapid time cycle after completion of the pressing process. A pressure accumulator (7) is additionally operated by the press rams (6).