GB453712A - Improvements in and relating to variable speed gear mechanism for cycles and the like - Google Patents

Abstract

453,712. Change-speed chain gearing. NEALE, W., and NEALE, J. A., Willowdene, New Bradwell, Bletchley, Buckinghamshire. March 28, 1935, No. 9697. [Class 80 (ii)] [See also Group XXXI] Change - speed gear mechanism for cycles comprises a driving chain-wheel, the diameter of which is varied stepwise by holding fast a cam disc 16, Fig. 1, and then displacing the cranks 6 angularly. The expansible wheel comprises two opposite sectors 10, Fig. 3, with pitch teeth, and four other sectors 8 without teeth, which sectors are all moved radially together in changing speed. The pulley sectors 10, 8 slide radially in runways 14 in a carrier plate 15 which is rigid with the crank axle 2. Each of these sectors carries a pin 18 with a bowl upon it engaging each with a separate stepped cam slot 17, Fig. 1, in the disc 16. The disc 16 normally revolves with the plate 15 and there is a spring 27, Fig. 1, passing round over all the pins 18 pulling them inwards radially. To change the gear ratio, the pedals are turned backwards to about 45‹ slope until, as shown in Fig. 1, a stop 15<b> on the disc 15 is caught by a pawl 38 upon the cycle frame. One of a number of recesses 25 in the cam disc 16 is then opposite a spring plunger 26 which is then released from the handle bars. As the plunger 26 drops inwards to lock the cam disc 16, a lug 26<a> upon it engages and releases the pawl 38. The pedals 6 are then displaced angularly one way or the other relatively to the locked disc 16 according to whether it is a change up or down. The pins 18 ride up or down simultaneously in the slots 17 and are locked in steps such as 23. The bolt 26 is then withdrawn and pedalling resumed. An arcuate recess 15a, Fig. 3, engaged also by the released plunger 26 limits the displacements possible to the pedals during speed changing. The spring arm 29 of a tensioning jockey 28 may by its position indicate the gear in use.