Patent GB-353010-A (GB)
Title: Improvements in and relating to change gear devices
IPC: F16H61/02
Filed: 1930-02-17
Abstract: 353,010. Variable-speed gearing. BLACKSTOCK, G., 52, Warren Road, Toronto, Canada. Feb. 17, 1930, No. 5321. [Class 80 (ii).] Relates to change-speed gearing of the type in which a change down is effected by the load, and a change up by slowing the driving-shaft, as by throttling the engine upon a vehicle. It comprises an arrangement similar to one described in Specification 349,492 with friction instead of dog clutches. The control is effected by a centrifugal yielding coupling 16, 11, Fig. 2. Arm 16 is secured to a boss 1x, Fig. 1, on driving-shaft 1 to which are also secured carriers 88, 89 for the control parts 74, 75, 90, 91, Fig. 10, of the train friction clutches. Disc 11 is secured to a loose sleeve 12, Fig. 1, which carries rigidly a gear 35 and a cage 67, Fig. 3, upon which the pairs of driving parts 68, 69 and 102, 103 of the train clutches slide. The driven disc 61 of the middle-gear clutch is connected by spokes 62 to a gear 59 loose on sleeve 12. The driven disc 105 of the direct-drive clutch is connected by spokes 106 to a gear 53 fast on driven shaft 2. A countershaft 3 carries fast gears 52, 58 and a loose gear 36 meshing with the gears 53, 59, 35, respectively. Gear 36 is connected to shaft 3 by a oneway clutch 40 which comprises a female coned ring adapted to be thrust over a cone 38 fast on shaft 3 by saw-teeth 42 on the gear. The low speed is through train 35, 36, 40, 3, 52, 53 and the middle speed through train 59, 58, 3, 52, 53. The middle speed and direct drive are brought in in succession, with clutch 40 overrunning, by actuating clutches 61, 105, which is done automatically bv the relative turning of the parts 16, 11 of the yielding coupling. To arm 16 are pivoted centrifugal links 18, Fig. 2, which carry bowls 19 engaging cam recesses 23 upon the face of disc 16. The arm 16 may also carry light levers 28 carrying bowls 29 pressed by springs 30 against cam surfaces 31 on disc 11. The cams 23, 31 are so shaped that the control coupling in effect locks in gear positions, and the whole device is used so that during gear change, when the coupling yields, the load on the gearing is eased. When the coupling yields, it carries parts shown in Fig. 10 in one plane, 19, 29, 91, 90, 75, 74, 48 all together to the left of the Figure. The bowls 74, 75 ride up on ramps 72, 73 on the backs of clutch discs 69, 68 causing the latter to grip disc 61 firmly to effect middle speed. On further yielding of the coupling, that pair of bowls passes that pair of ramps, and bowls 90, 91 ride up on ramps 100, 101 on the backs of discs 102, 103 to cause the latter to grip disc 105 firmly to bring in the direct high-speed drive. These bowls are supported in staggered relation as shown in Fig. 1 to prevent both train clutches being in full engagement together. The element 48 upon the boss 1x is arranged to allow cone 40 to be lightly engaged during the engagement of the middle-speed clutch 61 to synchronize it, and to hold cone 40 idle on change to direct drive. The gearing is disconnected by disengaging an engine clutch, or by sliding gear 52 out. Reversed drive is obtained by connecting gears 52, 53 through idlers.