Patent GB-1499814-A (GB)
Title: Winch
IPC: B66D1/74
Filed: 1974-05-10
Abstract: 1499814 Change speed control LEWMAR MARINE Ltd 30 April 1975 [10 May 1974] 20678/74 Heading F2D [Also in Division B8] A manually operated winch comprises a plurality of gear trains operable between a drive input shaft 12 and a drum 2, one of the trains driving the drum forward upon rotation of the shaft 12 in one direction and another of the trains being for running back of the drum upon opposite rotation of the shaft 12, the trains incorporating unidirectional drive means whereby the respective trains are automatically rendered operative upon rotation of the shaft 12 in the respective direction. To engage a direct drive of the drum 2, a main drive shaft 8 extending coaxially with the drum and driven through bevel gearing 13 from the radial input shaft 12, is coupled through a pawl  and ratchet arrangement 16, 37 directly to the drum once a button 26 has been manually depressed allowing a spring 45 to radially project the pawls of the arrangement 16, 37 for operation during rotation of the shaft 12 in one direction. This depression of the button 26 also projects a pin 50 into the path of a fixed pivot ratchet pawl 54 which permits passage of the pin 50 only during direct drive rotational direction. To engage the second speed the drive shaft 12 is reversed and the drum is driven through pinion 20 on the shaft 8 and through associated gearing to internal gearing 22 on the drum 2. During drive in this gear, the pin 50 is driven in the opposite direction and engages the pawl 54 which causes tensioning of the spring 45, and retraction of the pawls of the arrangement 16, 37. The pawl 54 is formed as a ramp which upon engaging the pin 50 moves it and hence the button 26 up into its original position. Upon again reversing the drive shaft rotation therefore, a third gear is selected through a pinion, 21 on the shaft 8 and through associated gearing to the internal drum gearing 22, providing the button 26 has not been again depressed. Drive from the input shaft 12 as well as going through the gear 13 to the shaft 8 also goes through a lost motion linkage 61, 62 to a worm 60 which meshes with a pinion to a shaft 64 including a further pinion 65. The latter is mounted through a unidirectional device drivingly connected to the drum internal gear 22 through the intermediate gearing incorporating unidirectional devices, used in transmitting drive to the drum from the pinions 20 and 21 on shaft 8. During drive of the drum through the said third gear, the worm 60 is also driving its run back gearing but due to the gear ratios the drive from the worm 60 is overrun and ineffective. If, however, the shaft 12 is reversed a unidirectional device 75 in gear 76 becomes ineffective which then allows the drum to run back without a positive run back drive. This mechanism also provides a lock for the drum when the input shaft and hence worm 60 is stopped. Selection of run back gearing instead of the second gear ratio when the shaft 12 is reversed after selection of the third gear is effected by the action of a push-rod 32 secured to and movable by the push-button 26. Upon depression of the button and hence rod 32, a cross-pin 81 is engaged to push a collar 82 downwardly clear of a pawl 78 of a unidirectional device on the pinion 20 so that the second gear is effective upon the first reversal of the drive shaft. During second gear operation the button 26 and the rod 32 return to their upper positions but the collar 82 is retained in its lower position by the pawls 78 operating. Upon the next drive shaft reversal for third gear selection, the collar 82 can move upwardly under spring bias past the inoperative pawl 78 which is thereby held out of operative position so that upon further reversal of the shaft 12, the run back gear is selected and not the second gear.