Method for drive control for hydraulic press - blocks pressure medium flow to retraction cylinders after working stroke, to prevent return stroke

摘要

The method is for use with forming machines, esp. a hydraulic press or forging machine. The machine has pump cylinders, charged by a crank drive, and retraction cylinders, which are under pressure from permanently rechargeable accumulators. After a working stroke, the pressure medium flow to the retraction cylinders is blocked. This prevents return stroke, and pressure fluid is sucked from the low pressure vessel into the working cylinder of the forming machine. Working and pump cylinders (2,4) are connected via a conduit (3), which is connected to the low pressure vessel (7) via a nonreturn valve (6). A second valve (15) is located in a conduit (13), which connects the retraction cylinders (9) to the fluid accumulator (14)/low pressure vessel. ADVANTAGE - Allows stroke displacement and longer overall strokes.