GB303327A - Improvements in change-speed devices for bicycles and the like - Google Patents

Abstract

303,327. Schmieder, E. May 29, 1928. Variable-speed gearing comprises a bevel differential train 5, 38, 34, the planet carrier 36 of which is the driven element, one side gear 5, Fig. 1, is the driving-element, and the other side gear 34 is driven from the first side gear through spur epicyclic variable-speed gearing. In the adaptation to a cycle hub shown, the whole is assembled about a fixed axle 1 and the carrier 36 drives the hub 47 through pawls 43, Fig. 4, to allow coasting. There are two two-speed spur epicyclic trains connecting the bevel gears 5, 34, one at each end of the hub. The spur gear on the right turns within a hollow member 3 which secures the bevel gear 5 to a driving- sprocket 4. Planets 9, 10 in a loose carrier 7 mesh with a sun 6 fast to member 3, and with a sun 11 fast to a sleeve 12, which passes through the carrier 36. The spur gear on the left has planets 31, 32 in a loose carrier 28. which mesh with a sun 26 on sleeve 12, and with a sun 33 secured to bevel gear 34. Each spur train yields a solid drive by clutching, and a reduced speed by anchoring the planet-carrier 7 or 28 to the axle 1. The side gear 34 and therefore the differential carrier 36 and hub 47 can thus be driven at four speeds, the highest being solid. The carriers 7, 28 are anchored by being engaged directly at 19 and 19<1> by sliding transverse keys 21, 21<1>, respectively. The locking solid is effected by clutch discs 17, 17<1>, shown also in Figs. 9 and 10. These discs have feathered connections 18 with the carriers and arc adapted to be pushed by the keys 21, 21<1> into clutch engagement with dogs 24 on the gears 6 and 26 respectively. The clutch recesses 23 in the discs 17 have one inclined edge each, and the dogs 24 are similar, the effect being that the discs become disengaged from the dogs when the keys 21 are moved away. Operation is effected by moving the keys by way of the angle-ended rods 50, 51, Fig. 1, passing within the axle 1. The ends 50, 51 engage a spring- returned rotary cam barrel 52.