| 摘要 |
<p>A remote control system for the jack cylinders of a hydraulically operated crane includes a plurality of regulating valves for controlling respective jack cylinders, the regulation of each valve being controlled by the movement of a respective valve spool connected to a respective lever forming part of a linkage including an arm mounted on a rotatable shaft and connectable to the shaft by a respective electromagnetically operated clutch so that by engagement of one said clutch and rotation of the shaft to a predetermined position the corresponding valve spool may be correspondingly positioned to move the associated jack cylinder accordingly.</p> |
