GB640062A - Improvements in cycle hub gears - Google Patents

Abstract

640,062. Variable-speed gearing. GATES, G. R. G., and DINAN, E. Jan. 3, 1948, Nos. 235 and 952. [Class 80(ii)] The invention comprises improvements to that of Specification 593,644 by the addition of further cam faces to provide three gear ratios and processional changing by back pedalling, and of lost-motion means to make less critical the degree of back-pedalling required. As shown, a hub 18 is rotatable on bearings 14 on a stationary spindle 12 and is driven by a sprocket 47 and an element 15 having fingers 26. These drive the dogs 27 of a torque carrying element 28 loaded by a spring 46 and which is axially movable by engagement of a dog 42 thereon with the surfaces 54-57 of a cam 36, which surfaces correspond respectively to bottom, middle, top, and middle gears. In the first, two gears, a sleeve 22 is driven through its spline 29 by the dogs 27, which in bottom gear (as shown) disengage pawls 24 and drive through an annulus 21, planet pinions 49, a carrier 48 and a ratchet 52, 53, a sun 20 serving as a reaction member. In middle gear the pawls 24 are released and drive ratchet teeth 51. In top gear the dogs 27 engage dogs 27<SP>1</SP> of the carrier 48 and drive through pinions 49, sleeve 22 and ratchet 24, 51. The lost motion device comprises dogs on the cam 36 engaging similar dogs 58 on a. ring 58 whose spring-loaded pawl 34 controls the one-way rotation of the cam 36.