| 摘要 |
A hydraulically driven die carrier for a power press, the carrier comprising a bolster for carrying a die; a set of wheels supporting the bolster for horizontal rolling movement to position the die horizontally; a separate hydraulic drive motor for each of the wheels; a plurality of hydraulic lift cylinders for moving the bolster vertically relative to the wheels; and a hydraulic control system for operating the hydraulic drive motors and lift cylinders for horizontal rolling and vertical movement of the die carrier, the control system including a supply pump having two separate outputs for providing separate sources of pressurized hydraulic fluid for the hydraulic drive motors and for the lift cylinders; a reservoir of hydraulic fluid connected to the pump; valve means for connecting and disconnecting the separate sources of hydraulic fluid and the respective drive motors and lift cylinders; and means for locking the lift cylinders in their raised positions while the cylinders are disconnected from the supply pump so that the hydraulic fluid in the line used to lift the carrier can be returned directly to the reservoir without being overheated as long as the carrier remains in its raised position. The hydraulic control system preferably also includes deceleration means for progressively restricting the flow of the hydraulic fluid through the drive motors as the carrier approaches the position where it is desired to stop the carrier, and then terminating the flow of the hydraulic fluid to stop the drive motors at the desired position.
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