GB515712A - Combined free and fixed wheel driving-mechanism for cycles - Google Patents

Abstract

515,712. Combined free and fixed wheel hubs for cycles. CHAPMAN, W. H., and BEDFORD, S. J. June 9, 1938. No. 17231. [Class 136 (ii)] In alternative free - wheel and fixed - wheel driving - mechanism for cycles, a chain wheel mounted to rotate about the longitudinal axis of the wheel hub is provided with two sets of oppositely-directed internal ratchet teeth, one of which sets engages one or more spring-pressed free-wheeling pawls, while one or more fixedwheel pawls are also provided within the chain wheel for engaging the other set of teeth under the control of hand-operated mechanism, all the pawls being pivotally mounted on the hub or on one or more parts fixed thereto. A sprocket wheel 14 is mounted by ball bearings 16, Fig. 2, the conical ball-race 18 on the inner side being formed on a flange on an end-plate 22 fast on the hub 10, while the ball-race 20 on the outer side, is formed on a flange 25 of a detachable ring 26. The end - plate 22 carries one or more spring - pressed free - wheeling pawls coacting with a set of ratchet teeth 34 on the inner periphery of the sprocket wheel 14. The detachable ring 26 is held against the central part of the end-plate 22 by screws, and carries a fixed-wheel pawl 42, Fig. 1, coacting with a set of ratchet teeth 40 formed on the inner periphery of the sprocket wheel 14 in the opposite direction to the teeth 34. In order to provide a fixed-wheel drive, the pawl 42 is engaged with the teeth 40 by a spring and is controlled by means of a conical cam 64, which is slidable along the hub axle 12 by means of a control cable 88, a link 84, and a pivoted fork 72, the cam when moved to the right as shown in Fig. 3 effecting the release of the pawl 42 for freewheeling. The cam 64 engages the end 62 of a bent lever arm 58 secured to the squared end 54 of the rotary pivot pin that carries the fixed-wheel pawl 42.