Pressure equalisation system for vertical press - uses proximity sensors on connecting rod to control pneumatic balancing cylinders to eliminate play

摘要

The vertical press with vertical slides (2) guiding the block (3) which is raised and lowered by a connecting rod (4) above, has a pneumatic cylinder (7,8) each side of the connecting rod to counterbalance the weight of the block. A control system regulates the pneumatic supply to the cylinders so as to distribute equally the play between the small end (28) of the connecting rod, and the spindle (6) passing through it, for all positions of the stroke. The control system uses upper and lower proximity contacts (11,12) mounted on the connecting rod, each side of a stop (10) on the end of an arm (9) mounted on the block, forming a reference point. These contacts are used to control electromagnetic valves supplying the pneumatic cylinders.