GB1345124A - Winch mechanism for lowring a lifeboat launach or the like suspended from two falls into the water and hoisting it out of the water - Google Patents

Abstract

1345124 Winches SCHAT DAVITS Ltd 17 March 1972 12752/72 Heading B8B A winch mechanism for lifting and lowering a boat suspended from two falls of flexible element 1, 2, out of and into water subject to wave motion comprises two winding drums 3, 4 for the falls 1, 2, a main motor 69 for driving both drums through various gear paths selectable via friction clutches 17, 18, 32, 34, 49, 50 and 60, 61 and an auxiliary motor 41, 9 for driving each drum to take up slack in its fall, free wheeling clutches 10, 11 and 43, 44 permitting the auxiliary drive to overrun the main drive to the drum. The drive to the drums 3 and 4 from the motor 69, which incorporates a brake 70 automatically energized when the motor is stopped, comprises four input shafts 19, 35, 51 and 62 driven simultaneously by gearing from the motor, and each shaft being associated with an electro-magnetic friction clutch 17, 18, 32, 34, 49, 50 and 60, 61. With clutch 32, 34 engaged the two drums are driven at a relatively slow equal speed, and upon engaging the clutch 60, 61 a relatively fast equal speed is obtained, a freewheeling clutch 28, 29 permitting the drive through the clutch 32, 34 to be overrun. The drums may individually be driven at a relatively higher speed still by engagement of respective clutches 17, 18 and 49, 50, the drive from these clutches overrunning the basic drive by means of freewheeling clutches 22, 23 and 54, 55. A centrifugal brake 31 associated with the clutch 32, 34 is applied upon rotation of the shaft 30 when the said clutch is de-energized. A differential compensating gear 75, 76, 77, 78 may be used to bring the boat automatically into the correct position when influenced by wave motion. The compensating gear is driven by both drums 3 or any difference in rotation speeds therebetween causes the differential casing 75 to rotate and drive a contactor nut 84 along a screw 83 to make contact with either of two rods 86, 87 coupled electrically with the clutches 17, 18 and 49, 50, whereby the appropriate clutch is energized and the corresponding drum is speeded up until the nut breaks contact again and the boat is re-positioned. In another embodiment, Fig. 2 (not shown), the clutch 60, 61 and its associated shaft 62 is removed from the system.