| 摘要 |
<p>1,184,870. Winch drive arrangements. GEARMATIC CO. Ltd. 21 Oct., 1968 [25 March, 1968], No. 49845/68. Heading B8B. [Also in Division F2] The reduction gear drive for a reversible hydraulic winch drum 11 includes a multi-disc brake 21 operable on the annular gear 16 of an epicyclic train 12, 14, 16, the brake which is normally spring applied being hydraulically releasable to free the drum from the drive gear so that a load thereon can be given a controlled or an emergency free fall lowering. The drum 11 is driven by a carrier 13 for planet wheels14 which mesh with a sun wheel 12 on a drive shaft 10 and internal teeth 15 on the gear 16. The brake 21 for the gear 16 comprises discs set between pressure plates 25, 28 which are caused to clamp the discs due to levers 26 being pivoted about points 27 by a piston 30 biased by springs 29, the plates 25, 28 being unclamped when fluid is supplied to a cylinder 31 causing the piston to compress the springs 29. The fluid pressure at the cylinder 31 is controlled by a manual valve which controls the rate of bleed from the hydraulic system, that fluid which doesn't bleed from the said valve passes out of the system through a metering valve 18 driven by external teeth 17 on the annular gear 16. Therefore, with full bleed from the manual valve, the brake 21 is applied and the metering valve is stationary, and with no bleed from the manual valve the brake is fully released and the metering valve bleeds the full hydraulic flow. For the emergency free fall condition, the hydraulic pump is communicated directly to the cylinder 31 for instant brake release, the metering valve being by-passed.</p> |
