| 摘要 |
939,187. Variable-speed epicyclic gearing. FICHTEL & SACHS A.G. April 4, 1962 [April 7, 1960], No. 13044/62. Class 80 (2). [Also in Group XXXI] Back-pedalling of a driving member of a hub change-speed gear engages a free-wheel to cause axial movement of a shift sleeve bearing on a non-rotating thrust block which acts directly on the shifting member of the changespeed gear. A sprocket 8 rigid with a driving member 1 is mounted through bearings 51 on a hub spindle 17 formed with a sun gear 26 meshing with planet gears 25 mounted on a planet carrier 22. The planet gears mesh with a ring gear 7 connected by dog teeth 9 to a pawl carrier 10 having pawls 11 forming a free-wheel coupling between the carrier 10 and the hub shell 13. A gear shift sleeve 4 is splined to the driving member 1 and axially movable against a spring 31 to engage teeth 5 with corresponding teeth 6 or 21 on the ring gear 7 or the planet carrier 22. Back pedal movement of the driving member 1 engages a jamming roller free-wheel 14 to rotate a cam sleeve 15, having sloping teeth 16, to axially move a thrust block 20, in a slot 19 in the spindle 17, engaging directly with an internal shoulder in the shift sleeve 4 to change the gear ratio. The cam sleeve has outstanding ridges 29, 30 to prevent inadvertent change of ratio. The planet carrier 22 may have a threaded engagement with a conical brake member 57 engageable with a brake member 62 rigid with the hub shell. The relative travel of the shift sleeve 4 and brake member 57 being such that change of ratio always takes place before braking on back pedalling. In a modification the planet carrier is in freewheel connection with the hub shell to provide direct and low ratios: |
