GB390581A - Improvements in or connected with transmission gears for bicycles and the like - Google Patents

Abstract

390,581. Cycle driving-transmissions. REEKS, J. C., 15, St. James' Villas, Winchester, Hampshire. Jan. 4, 1932, No. 223. [Class 136 (ii).] In variable-speed transmission mechanism for bicycles &c. including gearing between the pedal shaft and the chain drive to the rear wheel, such gearing comprises two or more concentric rings of internal teeth of different diameters driven by the pedal shaft, means being provided for bringing any one of the rings into driving connection with the chain drive to the rear wheel. To the axle 15 of the pedal cranks 6 is fixed a disc 14 provided with concentric internally-toothed rings 16, 17 adapted to gear respectively with slidable pinions 9, 13, the hubs of which are extended and mounted in tubular brackets 7, 12 on the bicycle frame. These hub extensions are keyed to inner hub extensions 4a, 5a on sprocket wheels 4, 5, which are connected by a chain 1 to a free-wheel sprocket on the rear wheel. The slidable pinions 9, 13 are brought selectively into mesh with the rings 16, 17 to vary the gear, by means of cables &c. 24, 26 under spring control, these cables being connected by a bell-crank lever 25, 27 and a cable 28 to a control lever 29. In a modification, a single pinion is slidable along the cycle frame to a position for engagement with the desired toothed ring by a further sliding movement along its own shaft, the chain tension being maintained by jockey rollers etc.; or two pinions of different diameters may be slidably mounted on a single countershaft. The bicycle may be provided with an additional variable gear in the hub of the rear wheel, so that a large number of gears may be obtained.