| 摘要 |
953,040. Change-speed gear; one-way acting brakes. FICHTEL & SACHS A.G. Nov. 8, 1962 [Nov. 11, 1961], No. 42305/62. Headings F2D and F2E. Ratio selection in a change-speed planetary hub for bicycles &c. is effected by backpedalling so that an input member 1, Fig. 1, formed with cam grooves 37, 38, 39, Fig. 3, turns relatively to a selector sleeve 4, itself carrying a spring-biased cam follower 5 engaging the grooves and restrained from reverse rotation by a one-way detent 3, thus sliding the selector sleeve and a ratio establishing clutch dog 8 in the input member, to engage the clutch dog with various parts of a fixed sun gear-planet pinions-ring gear train 23, 24, 14 driving selectively through two sets of ratchets 16, 19 to a surrounding hub shell 26. In the position shown, drive passes from a sprocket 27 fast with the input member 1 to the clutch dog 8, received in axial slots 60 in the input member, and thence to pins 34 journalling the planet pinions 24, a step-up drive being transmitted to the ring gear 14 and through the ratchet 19 to the hub shell 26. The cam follower 5 engages the end 40 of the ring cam groove 37. To establish the second ratio (direct drive), the sprocket 27 is momentarily back-pedalled. The follower 5 slides through the transverse groove 41, sliding the selector 4 rightwards of Fig. 1 against the bias of a spring 6, to disengage the clutch dog 8 from the planet pins 34 and instead engage it with the ring gear 14. When forward pedalling is resumed, the follower 5 slides to the end 43 of the groove 38. To establish third ratio, the sprocket 27 is again back-pedalled, the follower 5 slides along a transverse groove 42 into the cam groove 39, sliding the selector 4 further rightwards against the bias of the spring 6, engaging the clutch dog 8 with the tails of the ratchet pawls 19 to hold them disengaged. The step-down drive is then obtained through the ring gear 14, the planet pinions 24, the planet carrier 13 and ratchet pawls 16, on a back-pedal brake member 17, to the hub 26. On initiation of forward pedalling, the cam follower 5 moves to the end 44 of the cam groove 39. To initiate a downshift, the input sprocket 27 is again back-pedalled. The follower 5 moves to the opposite end of the groove 39, slides up a cammed slope 45 and out of the groove, and the spring 6 forces the selector 4 &c. leftwards to establish direct drive. The follower 5 enters a short extension of the groove 38 blocked at 53. On again backpedalling, the follower 5 slides up a cammed slope 46 out of the groove 38, and the spring 6 again slides the clutch dog 8 &c. leftwards, to establish the step-up ratio, the follower falling once more into the groove 37. The sequence of ratio shift may then be repeated. The one-way detent between the fixed axle 25 and the selector sleeve 4 comprises claws 3, Fig. 2, in a thrust block 2, biased radially by compression springs 47 to engage ratchet teeth 28 in the sleeve, the thrust block &c. sliding axially with the selector sleeve and the claws &c. projecting through slots in the axle. |
