Patent GB-190612231-A (GB)
Title: Improvements in and relating to Change Speed Gears.
Filed: 1906-05-25
Granted: 1907-05-23
Abstract: 12,231. Rudge-Whitworth, Ltd., and Pugh, J. V. May 25. Variable-speed gearing; clutches; shaft couplings. -In an eccentric type change-speed driving-mechanism for cycles, an eccentric toothed wheel s gears with a concentric ring r, the members of the gear being arranged about a non-rotatable eccentric p in the form of a cage, which is movable laterally for the purpose of bringing different members into gear with the driving and driven elements. As shown in Fig. 1, the wheel carries pins x engaging with circular holes v in end disks t, u, which are loosely clamped in position by plates z held by slightly riveting over the ends of the pins or by other means. The parts are in the position for low gear when the drive is transmitted from the sleeve j to the hub through clutch teeth or dogs m, w, wheel s, ring r, external dogs q, and internal dogs o. By movement of the cage slightly towards the right, a free position is obtained, and further movement then brings the dogs q into engagement with both driving and driven members, so that the hub is turned with the sprocket-wheel. For the high speed, the cage is moved to the extreme right when the dogs m, q and v, o are in engagement, and the drive is transmitted from the concentric to the eccentric toothed member and thence to the lefthand disk t. If desired, the disks t, u may be dispensed with, in which case the ring r is provided with two sets of short dogs to engage long dogs upon the driving and driven members, the drive being transmitted to and from the eccentric wheel by the engagement of pins thereon with holes in the sleeve j and the hub, respectively. For effecting the lateral movement of the cage, a wire 5 passing through an eccentric extension 4 of the axle e operates a rod 6 or the like entering a recess 7 in the eccentric p, so that by pulling the wire a spring 9 is compressed and the cage traversed to the right as soon as the dogs register. A spring 11 moves the cage in the opposite direction. In a modification, the eccentric p is made integral with, or is secured to, the axle. In this case, the wheel s is carried by externally-screwed rings rotatably mounted upon a sleeve or bush passed over the eccentric, the rings being provided with side projections corresponding to the pins x. The gearchanging wire may pass into the eccentric above the axle, and, through a spring, may operate a cross-pin sliding in a slot in the eccentric and axle. In lieu of the pin-and-hole drive x, y, each pin x may carry an eccentric bush bearing loosely in a hole y; or pins x may be used in conjunction with pins upon the disks t, u ; or balls or rollers may be inserted in opposing pairs of recesses in the concentric and eccentric members ; or pins upon both members may be connected in pairs by rings ; or loose pins passing through the eccentric wheel may carry eccentric disks bearing in corresponding circular recesses in the concentric members ; or, as a further arrangement, Oldham couplings may be employed, in which case each side of the eccentric wheel may be formed with parallel ribs engaging grooves in a floating ring, the opposite face of which is grooved at right-angles to the first set of grooves to receive ribs or projections upon the disk t or u. Other forms of connexion than the clutch dogs may be employed between the driving and driven elements and the members of the cage. Thus, as shown in Fig. 17, the dogs upon the side disk may be replaced by pawls v, w of the type described in Specification No. 22,936, A.D. 1899, the teeth m, o being ratchet teeth and the external dogs upon the ring r being replaced by sets of pawls 40, 41, 42. As a further modification, the direct drive may be obtained by connecting the side disks to the driving and driven members when, as shown in Fig. 19, the teeth m, o are made sufficiently long to allow of the simultaneous engagement of the parts w, m, v, o. By constructing the device so that the driving and driven members may be connected in turn to the ecccntric wheel, a two-speed gear is furnis' ed.