Patent GB-903096-A (GB)
Title: Two-speed gear drive for bicycle hubs and the like
IPC: B62L5/14
Filed: 1960-05-26
Abstract: 903,096. Change-speed epicyclic gear and control. BENDIX CORPORATION. May 26, 1960 [May 29, 1959], No. 18656/60. Class 80 (2). [Also in Group XXXI] In a two-speed cycle hub gear, wherein ratio change is effected by slight back-pedalling, concentric, screwed sleeves 14, 25 are adapted to be respectively rotated at low and high-gear speeds by a driving sprocket 31 and have respectively threaded thereon male coned friction clutch members 15, 41, which when the sprocket 31 is rotated forwardly are axially moved to engage corresponding female coned surfaces in a driven hub 6 and, for low or high gear respectively, balk means responsive to backward rotation of the sprocket 31 selectively prevents or permits engagement of the high gear clutch member 41. Rotation of the members 15, 41 is resisted by drag sleeves 18, 44 having axiallyextending fingers 21, 46 engaging slots 22 in the member 15 and spring arms 19, 45 bearing frictionally respectively on a non-rotating brake presser plate 12 and member 41. The high gear balking means comprises a selector sleeve 47 fast in the high gear clutch member 41 and having drag spring arms 49 frictionally bearing on an indexing abutment ring 48 axially fixed but rotatable on the sleeve 25. The abutment ring 48 comprises inwardly-directed spring pawls 56 engaging undercut ratchet teeth 53 in a circumferential groove 52 of the sleeve 25 and outwardly-directed lugs 57 extending into the path of axial movement of the selector sleeve arms 49. Register of the lugs 57 with the arms 49 prevents engagement of the member 41 whereas register of the lugs 57 with spaces 58 between the arms 49 permits such movement. There are twice as many ratchet teeth 53 as there are lugs 57 and arms 49 and the relationship of the ratchet teeth 53 with the screw threads of the sleeve 25 and the orientation of the selector sleeve 47 in the member 41 is such that as the abutment ring 48 is indexed step-by-step with respect to the ratchet gear 53 the lugs 57 register alternately with the arms 49 and the spaces 58. In operation, with forward rotation of the driving sprocket 31, if engagement of the member 41 is balked by the lugs 57 and the arms 49 the low gear clutch 15 is traversed to engage and drive the hub 6 in low gear. For high gear the operator back-pedals slightly, thereby rotating the screwed sleeve 25 backwardly. The high gear clutch member 41, together with the selector sleeve 47, and the abutment ring 48 are held against backward rotation by the drag sleeves 18, 44 and the drag spring arms 49 respectively. The abutment ring is thus indexed one ratchet tooth 53 forwardly and upon subsequent forward rotation of the driving sprocket 31, since the lugs 57 then register with the spaces 58, the high gear clutch member 41 is permitted to engage and drive the hub 6 in high gear. The low-gear screwed sleeve 14 is fast with a carrier 33 having planets 34 meshing a fixed sun 36 and a ring 29 fast with the high-gear screwed sleeve 25. The hub gear may provide direct and overdrive, Fig. 4 (not shown), in which case the driving sprocket 31 is fast with the carrier 33 or, as shown, direct and underdrive, in which case the driving sprocket is fast with the ring 29. A multi-disc brake having discs 9, 11, respectively splined to the hub 6 and a fixed sleeve 2 is engaged when the driving sprocket 31 is backwardly rotated to effect sufficient rightward movement of the low-gear clutch member 15 to act on the non-rotating presser plate 12. Facial teeth 23, 24 on the member 15 and the presser plate 12 prevent relative rotation therebetween. Specifications 772,396 and 796,977 are referred to.