| 摘要 |
A pneumatic-hydraulic control is coupled with either a manually or numerically controlled punch press to rotate the turrets of the press to the proper positions. Pneumatic pressure is directed selectively to one of two fluid accumulators to force fluid from that accumulator through an open deceleration valve to drive a piston which in turn is coupled to a rack and pinion drive for rotating the turrets. The other side of the piston is exhausted through an open deceleration valve to the other fluid accumulator. A slider switch having a central stop contactor and two deceleration contactors is secured to the rack and moves with the rack across a linear multi-contact slidebar. One of the contactors on the slidebar corresponding with the desired station on the turret is energized. A deceleration contactor engaging the energized contact closes the deceleration valve of the driving fluid accumulator forcing the fluid to go through a restricted passage thus decelerating the turret drive. The stop contactor engaging the energized contact exhausts both fluid accumulators to stop the turret drive.
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