GB959351A - Improvements in or relating to two-speed hubs - Google Patents

Abstract

959,351. Change speed epicyclic gear. FICHTEL & SACHS A.G. July 27, 1962 [Aug. 2, 1961], No. 29044/62. Heading F2D. [Also in Division B7] In a back-pedal gearshift two-speed bicycle hub providing direct and overdrive as shown, or direct and reduced (Fig. 4, not shown), and comprising planets 17 on an input (or free) carrier 2 meshing a free (or input) ring 13 and a fixed sun 18, a sliding clutch sleeve 4, constantly engaging by arms in slots or teeth 5, the inner member 6 of one-way cam and roller, or pawl-and-ratchet output drive means, is selectively engageable with the ring 13 for overdrive (or direct drive) and the carrier 2 for direct (or reduced) drive. As shown, a body 8, rotated by the inner member 6, carries drive pawls engageable with the ratchet teeth 11 in the hub shell 12. A control member 20, rotatable on, and abutting, the clutch sleeve 4, has facial cam teeth 21 co-operating with cam teeth 23 on the ring comprising deep and shallow notches 22, 27. In Fig. 7 (not shown), the cam teeth may be rounded. The control member 20 and the body 8 are respectively held from reverse rotation by friction springs 25, 26. In the direct drive position the overdriven ring deep notches 22 engage the control member teeth 21. For shift, back-pedalling effects reverse rotation of the ring relative to the detained control member which, together with the clutch sleeve 4, is thereby leftwardly cammed by the cam surfaces of the teeth 21, 23 against a spring 28 until the teeth 21 engage the shallow notches 27 and the clutch sleeve 4 engages the ring 13 for overdrive. On further backpedalling the control member teeth 21 move relatively along the ring teeth 23 until they re-engage the ring deep notches 22 for direct drive. As shown, the body 8, in axial or radial cam or screw-threaded engagement with the inner member 6, has a conical portion engageable with a brake shell 14 expansible into engagement with the hub shell 12. Alternatively, a plate brake may replace the shell 14. when the bicycle wheel and hub shell are rotated backwards, the one-way output drive means releases the brake and prevents application thereof. The body 8 acts as a shift-limiting means. In Fig. 3 (not shown) dispensing with the brake, the body 8 is extended so as to be screwed into engagement with the adjacent bearing support and thereby limit shifts to one change.