GB845370A - Improvements in or relating to tractors - Google Patents

Abstract

845,370. Friction clutches; variable-speed gear. INTERNATIONAL HARVESTER CO. OF GREAT BRITAIN Ltd. April 17, 1958 [Sept. 2, 1957], No. 27544/57. Class 80 (2). [Also in Group XXXI] A selective-ratio gear-box with slidable gears has alternative high and low ranges of ratios obtained by driving a tubular lay-shaft 11, Fig. 3A, at high or low speed. Normal ratios for road work of a tractor &c. are obtained by driving the layshaft 11 through gears 8, 9 from a primary drive element 4 which is coupled to the input shaft dogs 1a by a slidable clutch 5. Gears 13, 14, 15 slidable on splines of the output shaft 12 are used to select the various ratios by engagement with gears 16, 17, 18 or reverse gear 19. Top gear is selected by sliding the gear 9 to engage dogs 12a on the shaft 12. An alternative range of low ratios is obtained by driving the lay-shaft 11 through reduction gears 6, 7, the gear 7 being selectively coupled to the shaft 11 through a dog clutch 10 arranged to engage only when the clutch 5 is disengaged. Top gear in the low range is obtained by engagement with the dogs 12a of the gear 9 which is driven from the gear 8 on the lay-shaft 11. A power take-off shaft 20 passes through the hollow shaft 11, and may be independently driven from the engine or a final-drive shaft 20A may be coupled to the output shaft 12 through gears 26, 26A and a dog clutch 28B. Friction clutches.-A pair of disc clutches 3, 30, Fig. 3B, are arranged for independently driving the main gear-box input shaft 1 and a hollow shaft 29 coupled to the power take-off shaft 20. The clutches 3, 30 are operated by a single control lever through a cross-shaft 42, bearing assembly 44 &c. and spiders 44, the arrangement being such that initial movement first disengages clutch 3 to disconnect the tractor drive while a drive to the power takeoff through the clutch 30 is maintained. Further movement disengages clutch 30 to inter. rupt the power take-off. The friction discs are normally pressed into engagement by dished spring rings 36, 40. Initial movement of the pressure plate 35 to release the clutch 3 compresses the spring 36 until adjustable stops 49 on the plate engage the pressure plate 39 to release the clutch 30 against the action of the spring 40. Specification 824,186 is referred to. Reference has been directed by the Comptroller to Specifications 726,338 and 799,012.