| 摘要 |
953,095. Variable-speed gear. RALEIGH INDUSTRIES Ltd. Jan. 28, 1963 [March 29 1962], No. 11990/62. Heading F2D. [Also in Division B7] In an epicyclic change-speed hub gear incorporating a back-pedal brake, a pawl and ratchet mechanism for rotating a ring gear 19 in reverse to effect brake engagement is retained in an inoperative condition during driving, and means are provided for disengaging a selector sleeve 14 from a planet cage 18 if braking is effected when high gear is selected. A sprocket 29 is mounted on a driver 12 engaging a selector sleeve 14 which is slidable by means of a control rod 15 from a high gear position wherein splines 14a engage dogs 18b on the planet cage 18 and pawls 20 on the ring gear 19 drive the hub 11, to a direct drive position wherein the splines 14a engage dogs 19a on the ring gear, or to a low gear position wherein the splines 14a remain in engagement with the dogs 19a but also depress the pawls 20 so that the hub is driven by pawls 24 on the planet cage 18. Engagement of the driver 12 with the selector sleeve 14 is effected by splines 12a, 14b (Fig. 2), provided with lost motion such that when the driver 12 is rotated in reverse the tails 25a<SP>1</SP> of pawls 25a are released by the splines 14b, whereupon the pawls 25a engage teeth 25b to transmit the reverse rotation to the ring gear 19 and thence to the planet cage 18, which actuates a brake cone 21 effecting engagement of a brake lining 22 with a drum 23. Disengagement of the selector sleeve 14 from the planet cage 18, upon rotating the driver 12 in reverse to apply the brake, is effected by inclined rear faces formed on the splines 14a and the dogs 18b (Fig. 3, not shown). |
