GB191125680A - Improvements in Variable-geared Coaster Hubs for Bicycles. - Google Patents

Abstract

25,680. Olsen, F. J. Nov. 17. Variable-speed epicyclic gearing.-In a two-speed coaster hub for bicycles in which change of gear is effected by back-pedalling, an axially displaceable sleeve m, adapted to transmit the drive on one gear and to operate the brake on back-pedalling, is arranged to make relative rotation with respect to the driving-sleeve d in such manner that on backpedalling the sleeve m is displaced axially for removing a friction ring n from engagement with a screw-threaded clutch-sleeve h controlling the sun-wheel g. As shown in Figs. 1 and 3, the connexion between the sleeves m, d is effected by studs z upon the sleeve m engaging helically-disposed slots of different depths in the driving-sleeve, and in the high-gear position shown in Fig. 1, these studs occupy the right-hand end of the long slots 1. On back-pedalling, the studs pass through grooves 4, 5, Fig. 3, and finally occupy the position z<1> in a short slot 2 ; the brake may then be fully applied by further back - pedalling. If, however, the sprocket-wheel is turned forwards, the studs pass to the position z<2> in the slot 2 so that the sleeve m is retained in a position to the left in which the friction ring n is clear of the screw-threaded clutch sleeve h, and the drive is then on the low gear. On back-pedalling again in order to obtain the high-gear, the studs pass through grooves 6, 7 and take up the position indicated at z<3>, whereupon the brake may be fully applied ; if, however, the drive is resumed, the studs pass to the position z', whereupon the friction ring again engages the clutch sleeve and returns it to its position for locking the sun-wheel to the axle. The low-speed drive is transmitted to the hub through cam surfaces upon double pawl-like members p pivoted upon the ballbearing member 13, the brake being operated by other cam surfaces upon the pawl members engaging an anchored brake ring f and pressing it into contact with the hub. In a modification, a ratchettoothed ring 8, Fig. 6, fixed to the driving-sleeve d engages corresponding teeth 12 on a ring 9, which is loosely mounted on the sleeve and provided at its inner end with notches of different depths. These notches are engaged by ratchet-shaped projections z on the axially-displaceable member m, the projections being arranged in gaps 10 at the end of the driving-sleeve. On back-pedalling, the projections z pass from one set of notches to another of different depth and are then engaged by the driving-sleeve at the opposite side of the gaps 10 so that the brake may be fully applied. On resuming the drive, the projections hold the loose ring 9 until the ring 8 fixed to the driving- sleeve has snapped over one tooth, and the projections z are then again at the driving side of the gaps 10 with the member m displaced to the left or right as the case may be. In a further modification, the teeth on the driving-sleeve and the loosely mounted ring point in the opposite direction to that shown in Fig. 6, and with this arrangement, on back-pedalling, the part d first snaps a tooth relatively to the tooth 9, and the projections on the member m only move from one set of notches to another when a forward rotation is again given to the driving-sleeve.