Hydraulic power press with servo-control - has mechanical feed back system actuated by chain or cable

摘要

The servo-control of a hydraulic press has a mechanical feed back system. The cross-head of the press is connected by chain or cable to a drum which rotates on a screwed shaft. As the drum rotates it approaches the worm wheel and when the projections come into engagement the worm is pushed in the axial direction. This axial motion of the worm is transmitted through the shaft and hydraulic intensifier to the camshaft (28) of the control valve. When the control lever is actuated in order to move the cross-head to a required position, the camshaft (33) is rotated. This rotation of the camshaft actuates the control valve which directs hydraulic fluid to the jacks. When the cross-head has reached this required position the feed back mechanism closes the control valve and stops the cross-head.