GB189813313A - Improvements in and connected with Bicycle Driving Gear. - Google Patents

Abstract

13,313. Fairfan, J. F. A. June 14. Driving-mechanism for bicycles. The treadlelevers 17 are loosely mounted upon the axle 16, and have sheaves 22 mounted upon the bosses 18 thereof. A cord 26 passes round and is secured to each sheave, and is carried through the stays 8, 8<a> to a corresponding sheave 27 which is connected by clutch mechanism to the rear-wheel hub. The upper stays 8 are connected together by a brace 12 and by a strut 13 to the frame member 6, and the lower stays 8<a> are connected by a brace 14 and a strut 15 to the bottom bracket. Each of the sheaves 27 runs upon ball bearings in a ball cup 29, which is attached to the wheel hub 30. Spring- controlled dogs 33, which have their ends seated in notches 32 in the sheave, are provided with notches to receive a rib 31 mounted upon a flange 28 of the ball cup 29. By this arrangement the dogs bind upon the rib in one direction, and serve to propel -the bicycle and run freely upon the rib in the opposite direction. The treadle-lever bosses 18 are provided with recesses 19 which engage projections 20 on the bottom bracket to limit the motion of the treadle-levers. The sheaves 22 are connected by a cord 23 passing over a pulley 24 mounted in a spring frame 25 to cause the treadlelevers to swing alternately. In a modification, a clutch is mounted upon the crank axle, and motion is transmitted to the rear wheel by chain gearing. In another modification, a single length of cord is used which passes from one sheave on the crank axle to the rear clutch, through the rear stay tubes, and over a spring-controlled idle pulley to the other rear clutch, and from there to the corresponding sheave on the crank axle. An adjusting- screw may replace the spring in the idle pulley. Other forms of clutch may be used, such as ball &c. clutches, and clutches of the type described may be used in connection with the rear sprocket-wheel of an ordinary bicycle.