| 摘要 |
1529331 Controlling winches CLARKE CHAPMAN Ltd 22 Feb 1977 [2 March 1976] 16954/75 Heading B8B A winding mechanism for lifting and lowering a load relative to a surface subject to elevational variations, comprises a winding drum 10 driven by pivot and second reversible motor 12, 20, the motor 12 driving the drum 10 directly whereas the motor 20 is drivingly connected to the drum through a unidirectional over-run device 14, the motor 20 also having means selectively operable to eliminate at least the majority of turning resistance imposed by the motor 20 on the drum 10. The operable means may comprise an idling setting on a control valve if the motor 20 is hydraulic or a clutch if the motor 20 is electric. The motor 12 is a compensating motor to continually bias a line on the drum 10 during said elevational variations and the main motor 20 superimposes its drive, through a pawl and ratchet device 14, on to the drum 10, already influenced by the motor 12, for lifting and lowering operations. In the embodiment of Fig. 4 (not shown) a messenger drum and line are provided, the line being secured to a moving surface from or to which a load has to be moved by the main cable. A transmitter associated with each drum sends a signal to an error detector which produces a corrected output signal to control the main winch drum compensating motor.
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