Patent GB-1486777-A (GB)
Title: Winch
IPC: B66D1/74
Filed: 1973-12-19
Abstract: 1486777 Winches LEWMAR MARINE Ltd 12 Dec 1974 [19 Dec 1973 26 Feb 1974 10 May 1974] 58878/73 8687/74 and 20876/74 Heading B8B [Also in Division F2] In a multi-speed winch in which there is a plurality of drive ratios available between a central drive shaft 2 and a drum 6 which is always rotated in one direction, but with different drive ratios from the drive shaft when the latter is rotated in successively opposite directions, a first, direct drive ratio is engageable unidirectionally between the shaft and drum, or held uncoupled in accordance with the position of an actuator 7 resiliently biased by a torsional spring 8 towards the direct drive engage position, the spring 8 being automatically stressed when the actuator 7 is returned to its direct drive disengage position by a catch 18 when the drive shaft 2 is reversed. Pawls 21 pivoted to the shaft 2 at 4 are engageable with a ratchet 5 on the drum 6, provided apertures 10 in a skirt 9 of the actuator 7 permit the pawls to be spring biased outwardly into contact with the ratchet 5. The actuator 7 is movable axially and circumferentially relative to the shaft 2, but is restricted by a detent in the form of a pin 12 on the shaft extending into an L-shaped-slot 11 inthe skirt 9. To select the direct drive, the actuator 7 is moved axially downwardly on the shaft 2 against the spring 8 by an operator depressing a button 14 secured to a ring 16 having projections 17. The slot 11 then moves down and the pin 12 moves to the end of the horizontal limb of the slot by residual torsion in the spring 8 rotating the actuator relative to the shaft. This relative rotation causes the apertures 10 in the actuator skirt to move into a position allowing the pawls 21 to move radially to engage the drum ratchet 5 for direct drive. Upon reversal of the drum drive shaft 2, the catch 18 which is uni-directional and is mounted on a stationary portion 19, prevents reverse rotation of the actuator 7 whereby the shaft 2 and pin 12 move relative to the slot 11 in the actuator skirt 9 until the slot permits the actuator to move upwardly as biased by the spring 8, and clear of the catch 18, this relative rotation between actuator and shaft pre-stressing the torsional spring 8 ready for the next direct drive selection. In another embodiment Figs. 4, 5, 6 (not shown) the actuator comprises a skirted ring (117) which is rotatable only and is rotationally spring biased into a direct drive engaging position. The detent comprises a spring loaded stud (127, 128) which is manually depressed to select direct drive and is engaged by a unidirectional cam ring (130) upon reverse rotation of the drum drive shaft (108) to cause relative rotation between the shaft and actuator ring to disengage the direct drive and prestress the actuator ring spring. In a final embodiment Figs. 7 to 13 (not shown) the actuator (226) is positioned coaxially of the drum and is directly pushed by the operator, the detent arrangement including radial pins (236) in a pawl ring (216) engageable with slots (235) in the actuator. In this embodiment the drive shaft is driven through gearing from a radial worm mounted at the base of the winch.