GB248345A - Improvements in or relating to variable speed gears - Google Patents

Abstract

248,345. Aeppli, A. Feb. 27, 1925, [Convention date]. Variable-speed epicyclic gearing is controlled by a ratchet linkage which connects two elements of the train and rotates bodily round an adjustable eccentric axis. Thus a driving- shaft 1, Fig. 1, supports a frame 2 which carries stepped planets 3, 4 meshing with a sun gear 6 on a driven shaft 5 and a sun gear 8 which is controlled or driven through multiple-phase ratchets 18, Fig. 2, upon a sleeve 7. A drum 9 surrounding the ratchets is supported revolubly in a transverselydisplaceable carriage 11 and is connected by a drag-link 10, Fig. 3, to the planet-carrier 2. Ratchet arms 12 are connected by links 14 to the interior of the drum 9. When the drum 9 is concentric with the shaft 5, the ratchet gear and the epicyclic gear both turn solid, the resulting one-to-one drive being the lowest speed transmitted. As the carriage 11 is displaced, the arms 12 move round alternately faster and slower, and as each arm acts when moving fastest, the sleeve 7 and gear 8 are driven at increased speed. The speed of the shaft 5 thus increases from normal. The linkage connection 10 causes the speed of the drum 9 and therefore the speed of the shaft 5 to vary cyclically. In high-speed arrangements, the drum 9 may be driven uniformly from the carrier 2 by a pair of toothed gears 24, 25, Fig. 6, upon a fixed countershaft 16. Speed is varied by swinging the drum 9 round the shaft 16 as centre. The gears 24, 25 may be stepped so that the lowest speed is less than one-to-one. Resilient elements and fly-wheels may be used to render the drive still more smooth. The pawls 17, Fig. 2, are adapted to rock on pivots 19 within the arms 12, and the ratchet teeth and pawls are so arranged that when one edge of a pawl is over a ratchet tooth, the other edge of the pawl projects into the tooth gap. Provision is made for reversing the direction of drive of the ratchets to meet the case of interchange of functions of driving and driven shafts, as when a vehicle is coasting. The arms 12 are for this purpose moved laterally between two oppositely-set ratchets 18, 18<1>, Fig. 8. In modified arrangements, three-element spur epicyclic trains are used; bevel trains may also be used.