| 摘要 |
A hydraulic control device connected to one of a series of shifting rams in a hydraulic system for shifting a conveyor in a mine working. The device is composed of a piston disposed in a cylinder and one or more displaceable stop members for limiting the movement of the piston and thereby regulating the quantity of pressure medium supplied to the ram. The position of the, or each, stop member can be altered with a cam or similar eccentric rotatable member connected to a manually operable control knob. An automatic change-over valve is preferably used to connect the working chambers on either side of the piston to either a pressure source or to the ram. |
