Patent GB-977370-A (GB)
Title: A jib sheet winch
IPC: B66D1/74
Filed: 1963-04-17
Abstract: 977,370. Controlling change-speed gear and clutches. CLYDE ENGINEERING CO. PTY. Ltd. April 17, 1963 [April 19, 1962], No. 15048/63. Headings F2D and F2L. [Also in Division B8] In a geared system for hand cranking a pair of winch-capstans 55, Fig. 1, from crank handles 8 on a pair of pedestals 3, first changespeed gears-incorporated in crank cases 5 at the top of each pedestal are coupled through vertical shafts to second change-speed gears in gear cases 1 at the base, and the drives are selectively interconnected by a clutch-engaged cardan shaft 68 so that one or other of the capstans 55 may be driven from both sets of crank handles 8. The change-speed gear in the crank case 5, Fig. 2, comprises a pair of oppositely acting ratchet mechanisms 14, 15 on the crank shaft 6 arranged so that reversed rotation of the crank handles selects alternative drive ratios to a vertical shaft 13 through bevel gears 9, 11 or 10, 12. The gears are so arranged that the shaft 13 is rotated in the same direction irrespective of the direction of rotation of the cranks 8. The vertical shaft 13 is coupled through the second change-speed gear to an axially aligned shaft 22 carrying a sprocket 52 for a chain drive 58 (Fig. 1) to the capstan 55. The second change-speed gear comprises a slidable dog clutch 29 keyed to the shaft 22 and alternatively engageable with dog teeth 21 on the end of the shaft 13 for direct drive or with teeth 28 on a gear 26 driven through gears 23, 27 on a countershaft 24 to obtain an overdrive ratio. A ratchet gear 59 is arranged in the drive between the shaft 22 and the sprockets 52 to permit the capstan 55 to be overrun by hand in taking-up slack of jib sheets &c. A further ratchet gear 62 arranged between the shaft 22 and a fixed bearing housing 64 prevents reverse rotation or unwinding of the capstan 55 under all conditions of the gears. The countershaft 24 carries a dog clutch 72 for transmission of the drive through bevel gears 66, 67 to the cardan shaft 68 interconnecting the two pedestals. The gear system of the other pedestal, Fig. 3 (not shown), is identical to the above with the exception of the clutch 72 which is omitted. The clutch 72, Fig. 5, is controlled from a throw-over lever 76 which moves a slider 81 through a crank pin 79 and link 80. The slider 81 is pressed into driving engagement by a spring 84 and the arrangement is such that the crank pin 79 moves over centre on release of the clutch 72 so that the spring 84 then acts to hold the clutch disengaged. The change-speed clutch 29 is operated by alternative actuation of a pair of foot levers 30, 31 coupled by links 32, 33 to a rockable shaft 35. A pin 38 on the shaft 35 is coupled by a link 39 to a slider 40 which is resiliently coupled by springs 45, 48 to a second 47 carrying the dog actuating fork 46. The first slider 40 is engaged by a spring 44 which operates in conjunction with the off-centre position of the pin 38 to hold the gear in one engaged position. A throw-over latch 49 is adapted to engage a locking bar 50 on the rockable shaft 35 to hold the gear in neutral and prevent operation of the pedals. Tubular stops 42a, 47a are arranged between the slider 40, 47 and operate so that the dog teeth are disengaged positively.