GB650494A - Improved transmission for bicycles - Google Patents

Abstract

650,494. Change-speed gear. SHEPHERD: R. W. J. March 24,1949, No. 13937/48. [Class 80(ii)] [Also in Group XXXI] . A bevel-geared shaft-drive for a pedal-cycle includes a direction-reversing spur-pair 19, 20, arranged, as shown, at the rear between a propellershaft 11 and a counter-shaft 21, carrying a bevel 22 meshing with that, 23, fast to the road-wheel hub 24, or, in a modification, arranged at the front between the pedalcrank bevel 1 and the propeller shaft. The reversing-pair provides for correct direction of wheelrotation with both end shaft-bevels arranged between the axes of the wheelhub and pedal-crank and both on the same side of their meshing bevels. A balanced drive is provided by the use of duplicated gearing, with a propeller shaft 11 arranged inside the lower frame tube 13 on each side of the cycle. The pedal-crank spindle 2 drives its bevel 1 through a ratchet-clutch 4. Three speed-ratios are provided by three rings 5, 6, 7 of bevel teeth on each face of the pedal-crank wheel 1, meshing freely-mounted pinions 8, 9, 10, which are selectively clutched to their propellershaft 11 by a single feathered dog 40, which clutches the bevel-pinions 8, 9 directly and the pinion 10 through 9, which last-named pinion (9) is moved simultaneously out of mesh with its driving ring 6 by the dog 40 when the latter is moved to the extreme rear against a spring 43, which is stronger than a spring 42 opposing its movement from the pinion 8 to 9. Dogs 40 on both sides of the wheel 1 are controlled simultaneously through a Bowden-operated forked lever 44.