GB285558A - Improvements in variable speed gear - Google Patents

Abstract

285,558. Rushfirth, S. Nov. 17, 1926. Variable-speed epicyclic gearing comprises a planet-carrying gear box i, Fig. 1, with a combined clutch and brake member m slidably splined thereto outside and biased by a spring n to hold the clutch m<2> in engagement so as normally to yield a high-speed solid drive. The member m<2> engages a female clutch member d fast on a driving-shaft c'. When the member m is thrust to the left by suitable means t, the clutch is disengaged and a flange m<1> is pressed with braking effect against a fixed friction surface b<2>. The carrier box i is thus held against rotation and a lower speed is transmitted. Two such gears are shown in series in Fig. 1, the one on the left yielding a reduced speed only, the one on the right a reversed drive as well. In each of these is a pair of stepped planets k, l meshing with gears e, h on driving and driven shafts respectively, the train e, k, l, h being operative for reduced speed. In the form on the right this train is designated e<1>, k<1>, P, h<1> and reversed driving is effected by sliding the gear h<1> out of mesh with the gear l<1> into mesh with an idler s<2> driven from the gear k<1>. In Fig. 5 is shown a form of gear which may be arranged within the carrier box i and yields three forward speeds and one reversed drive. There is the solid drive, and the first reduced speed through train e', k<1>, l<1>, h<1> as before. A gear h<2> loose on the end of the driven shaft c<2> constantly meshes with an additional planet o. The second reduced speed is effected by sliding the gear h<1> until the clutch face engages a clutch face on the gear h<2>. The reverse is effected in the configuration shown through an idler s<2> as before. In Fig. 7 is shown a form adapted as an auxiliary series two-speed gear upon a vehicle. A coupling flange is shown at w for driving a change-speed gear of any type. A toothed rim v is for starting the engine.