| 摘要 |
<p>A marine crane includes a high speed winch having a hydraulic heave compensating system that automatically controls the crane winch to compensate for the vertical movement of a load during offloading operations. The heave compensating system includes a reversing valve for overriding manual control and for directing control pressure to stroke the pump of a hydrostatic winch drive into its raise mode of operation, and a compensating valve that regulates the displacement of the pump permitting it to develop and maintain only a predetermined pressure in the high pressure main fluid line. The heave compensating system preferably includes a lift control system for automatically hoisting a heaving load only at or near the crest or trough of a wave.</p> |
