GB850613A - Improvements in and relating to epicyclic variable speed gearing - Google Patents

Abstract

850,613. Change-speed gear. FELIX, J. W. Dec. 10, 1958 [Dec. 16, 1957], No. 39049/57. - Class 80 (2). [Also in Group XXXI] An epicyclic change-speed gear for a cycle hub providing three reduced, three overdrive ratios and direct drive over a three to one range or, with modifications providing eight, nine or thirteen ratios, comprises stepped planets 3 which mesh a fixed sun 1 and two or more ring gears 6, 8, 16 the planet carrier 4 and rings 8, 16 of which are selectively connected to a driven hub 13 by ratchet clutches 21, 11, 17 respectively whilst the planet carrier 4 and rings 6, 8 are selectively connected to an input sprocket 27 by sliding clutch members 25, 29 engaging an extension of the planet carrier 4 or pawls 7, 9 respectively the appropriate combination being selected by axial movement of a rod 35 actuated from a handle-bar control. The gear as shown is conditioned for top or seventh ratio, the sprocket 27 driving through a member 26 and clutch member 25 slidable thereon the planet carrier 4, the hub 13 being driven from the ring 8 through pawls thereon (Fig. 4, not shown), the ratchet 11, the pawls 17, 21 overrunning. For sixth ratio the control member 35 is moved one step to the right which through a spring 37 moves right a member 36 and the clutch member 25 connected thereto against a return spring 28 which clutch member moves right through springs 31, 33 the clutch member 29 and a ring 32 which trips the pawls out of engagement with the ratchet 11. The sprocket 27 drives the planet carrier as above, the hub 13 being driven from the ring 16 through the pawls 17, the pawls 21 overrunning. For fifth ratio the clutch members 25, 29 and ring 32 are stepped right, the ring 32 reaching the end of its travel, disconnecting the clutch member 25 and planet carrier 4 and engaging the ratchet 11 and 7, 29, the sprocket drives the ring 16 through the clutch member 29 and pawls 7 whilst the hub is driven from the ring 8. For fourth ratio, direct drive, the clutch members are moved a further step to the right, the clutch member 29 disengages the pawls 7 and engages pawls 9, the sprocket 27 driving, through the clutch member 29, pawls 9, and ratchet 11, the hub 13. For third ratio a further step right of the member 29 which reaches the end of its movement trips the pawls of the ratchet 11 out of action whilst maintaining engagement with the pawls 9, the hubs 13 being driven from the ring 16 through pawls 17. For second ratio the rightward step of the control member 35 engages the clutch member 25 with the pawls 7 and a spring 41 on the control member engages with and moves right a ratchet wheel 20 against a return spring 22 which wheel engages chamfered edges of the pawls 17 and trips them out of action. The sprocket 27 drives the ring 6 through the clutch member 25 and pawls 7 the pawls 9 overrunning and the hub is driven from the planet carrier through the ratchet wheel 20 and pawls 21. For first, the clutch member 25 is stepped right to engage the pawls 9 the sprocket thereby drives the ring 8. In Fig..6 (not shown) the ring 16 (Fig. 3) and wheel 20 (Fig. 3) carry the pawls whilst the ratchet is on the hub, rightward movement of the wheel 20 moves plungers which trip the pawls on the ring 16 out of action. In Fig. 2 (not shown) the ring 32 is replaced by spring fins attached to the clutch member 29. The hub may be fixed and the spindle revolve. The manually operable control, Fig. 1, comprises a ratchet plate 43 connected to the gear control rod 35 by a cable 42 and is retained in the desired setting by the arm 44 of a twoarmed spring pressed pawl 44, 45, which permits clockwise rotation of the ratchet 43 through any number of settings (i.e. reducing the gear ratio), whilst for anti-clockwise movement the arm 45 is manually moved into engagement with the ratchet 43 disengaging the arm 44 permitting a half-tooth rotation of the ratchet 43, and on release of the pawl, the arm 44 is spring pressed into engagement with the ratchet 43 releasing the arm 45 whereupon the ratchet completes its movement of one tooth (i.e. increases the ratio by one step).