Patent GB-190428087-A (GB)
Title: Improvements in Free Wheel and Brake Attachments and Two-speed Gears for Cycles.
Inventor: POWELL WILLIAM
IPC: B62M11/14
Filed: 1904-12-22
Granted: 1905-11-09
Abstract: 28,087. Powell, W. Dec. 22. Brakes ; driving-mechanism.-In a combined free-wheel, back-pedalling brake and two-speed gear for cycles, the brake and variable-speed mechanism are arranged at opposite ends of the hub, the chain-wheel effects the drive or operates the brake through oppositely-disposed pawls, so arranged that the one holds the other out of engagement, and the hub and the driving-steeve c are mounted upon separate sets of ball bearings p<1>, p<2> and c<1>, c<2>, respectively, adjustable from the outside by means of cones p<4>, d'. The pawls h, i, Fig. 3, are carried by the sprocket-wheel, and, in driving, the pawl h drives the sleeve c through a ratchet-ring g, so that high or normal low speed is obtained according to the position of a sliding clutch arrangement m. With jaws m' extending through a fixed cone into engagement with teeth k<4> upon the sun-pinion, the hub is turned at low speed through the internal teeth j and the planet-wheels k upon an end-plate k<2>. If, however, the clutch is drawn into the position shown in Fig. 2 by a cord m', arms m<6> of a ring m<5> passing through slots m<7> in the sleeve c engage notches o in the hub, which is thus driven directly. On cessation of pedalling, the pawl h rides over the teeth of the ring g, while, on back-pedalling, the pawl i engages the ratchet ring f, which through a studf', Fig. 6, moving in a slot e' operates an arm e<3> to expand a ring e into contact with the hub. A plate e' with flanges e<7> is held stationary by an arm e'. The pawls are provided with oppositelyacting springs h<1>, i<1>, while, in order that the mechanism may be silent, the opposed noses of the pawls are provided with overlapping extensions h<2>, i', so that the operative pawl holds the other clear of its ratchet ring. Two or more sets of pawls may be used. To admit of the cycle being wheeled backwards without operating the brake, either the points of the ratchet teeth or the noses of the pawls may be bevelled, as at h<3>. Thus, if the driving-pawl be in engagement with the ring g, the braking-pawl is held out of operation, and, upon the ring g moving backwards, the braking- pawl and the sprocket-wheel are carried with it and the brake is not applied. If, however, the pawl i is in engagement with the brake ring when the machine is wheeled backwards, the pawl h is held out of operation, and, as the ring g moves round, its teeth strike the bevel h<3> and slip under the pawl. As a modification of the sun-and-planet mechanism, the planet-pinions may be carried by the driving-sleeve, the internally-toothed ring being secured to the hub, in which case the hub is driven directly for the low speed. The Provisional Specification also describes arrangements in which an inner braking-ratchet is connected through a screwed sleeve with a hollow cone, pressed, on back-pedalling, into engagement with a braking-surface on the hub, or the ratchet may be shouldered into a disc or cone on a sleeve cunnected by a screw thread with a second sleeve carrying a disc or cone, so that, on back-pedalling, the cones are pressed apart and engage the ends of the hub.