| 摘要 |
An extracting screw apparatus comprises a hydraulic control which operates during starting of the extracting screw after a period of nonuse. The hydraulic control comprises a double-acting hydraulic actuator having a piston rod connected to an intermittent drive such as an overrunning clutch for rotating a driving shaft for the extracting screw about its axis. The intermittent drive converts linear reciprocating movement transmitted by the hydraulic actuator into intermittent angular movement. A hydraulic motor alone insures rotation of the extracting screw about its axis after starting and also insures the sweep movement of the extracting screw about a vertical axis. A hydraulic control circuit connected between a line running from a pump to the hydraulic motor for cutting off hydraulic fluid to the double-acting hydraulic actuator after normal operating torque is reached.
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