GB635043A - Improvements in or relating to bicycles and other vehicles propelled by a person or persons riding thereon - Google Patents

Abstract

635,043. Driving mechanism for rider-propelled vehicles. GOODWIN, A. P. Feb. 18, 1948, No. 4802. [Class 136 (ii)] In a rider-propelled vehicle having a flywheel connected through gearing to the driving mechanism so as to rotate, when the vehicle is driven, at a substantially higher speed than the input shaft of the driving mechanism, the flywheel is mounted for independant rotation on the input shaft and is connected thereto through gearing including at least one lay shaft. As shown applied to a bicycle, the usual bottom bracket is replaced by a pair of laterally spaced sub-frames comprising tubes 16, 17, 18, 19 supporting fittings 21, 21 which carry bearings 22, 22 for a crank axle 23. A flywheel 32 is freely mounted on the crank axle and is rotatable with a small sprocket wheel 33. A larger sprocket 34 is mounted on a hub member 36 screw-threaded on the crank axle, two oppositely acting one way clutches 48, 51 being provided between the hub member 36 and the sprocket 34. The crank axle drive is transmitted by the sprocket 34 and a chain 42 to a small sprocket 41 on a lay shaft 37, mounted between the sub-frames, and thence through further chains 44, 47 and sprockets 43,45, 46 to the small sprocket 33 and flywheel 32 so that the latter rotates at a substantially higher speed than the crank axle. As shown in Fig. 3, each of the one-way clutches 48, 51 comprises a set of pawls 52 urged by springs 53 into engagement with ratchet teeth 54 on the sprocket 34. The clutch 48 permits the flywheel to overrun the crank axle whilst the clutch 51 prevents such over-running but is manually releasable by means of a flexible band 55 which retracts the pawls 52 (Fig. 6).