Patent GB-190824961-A (GB)
Title: Improvements in Three-speed Geared Hubs for Cycles.
Inventor: SANGSTER CHARLES THOMAS BROCK
Filed: 1908-11-20
Granted: 1909-10-14
Abstract: 24,961. Sangster, C. T. B. Nov. 20. Driving-mechanism.-In a three-speed hub gear for cycles of the kind employing a single epicyclic train of which the internal ring and the planetpinion carrier are non-slidable and the sun-piuion is at all times prevented from rotating, a clutch upon the driving side of the train makes the high and normal speed connexions between the sprocketwheel and the carrier while another clutch makes the low-speed connexion between the sprocketwheel and the annular wheel, the arrangement on the driven side of the train comprising an automatic clutch for transmitting the low and normal speed drives from the carrier to the hub shell, and a second pawl clutch which transmits the highspeed drive and is positively controlled by a cam or suppression device operating to tilt the pawls when the parts on the driving side are positioned for making either the low or the normal speed connexion. Spur-toothed clutch rings j<1>, j<2>, Fig. 1, rotatably mounted upon the sun-wheel sleeve, effect the connexion between the sprocket-wheel e and the carrier b and are movable axially, together with the sun-wheel c and the cam-ring p. To enable the hub to be turned backwards for all positions of the gear, a one-way clutch g is interposed between the sprocket-wheel and an internallytoothed spur ring i ; this clutch co-operating with the ring j<2> or j<1> serves to drive the carrier for the normal or the high speed. With the parts in the position shown the tails o<3> of the pawls between the annular wheel and the hub are tilted by the ring p, the ring j<2> clutches the carrier to the sprocket-wheel, and the drive is transmitted at normal speed through the clutch g, parts i, j<2>, b and a one-way clutch n<1> to the hub, the driving- clutch h being overrun. When the central gear members are moved to the right so that the rings j<1>, j<2> are in engagement with the carrier and the ring i only, respectively, the drive is automatically taken up by the one-way clutches h, n<1>, and the hub is driven at low speed, the ring j<2> turning idly. Further movement of the sliding parts to the right brings the ring j<1> into engagement with both the ring i and the carrier and takes the cam-ring p from under the pawl tails o<3>. The drive is then at high speed through the clutch g, the parts i, j', b, the planet-pinions b<1>, the internal wheel a, and the clutch o<1>, the one-way clutches h, n<1> being overrun. The gear is controlled by a nut q with double threads engaging studs s<1> upon bars s. These bars, extending through slots r<3> in the fixed cone r and also working in the gaps between the feathers upon the axle whereby the sun-wheel is prevented from rotation, are connected at their inner ends to the cam-ring and the sun-wheel sleeve, so that when the nut is turned by a cable attached to the pulley q<1> the parts p, c, j<1>, j<2> are moved. Springs q<2>, t effect the return motion and tend to keep the parts in the normal or direct-drive position. The pivot ends of the clutch pawls are backed up by seatings in the pawl carriers adapted to take the drive. The sun-pinion may be fixed or made solid with the axle, and the clamp p and the clutch rings j<1>, j<2> may be mounted on sleeves which surround the axle. In a modification, the rings j<1>, j<2> are replaced by a single clutch ring j, Fig. 11, and the pawls o are mounted in a separate carrier k, which surrounds the cam-ring p and an extension b<2> of the planet-pinion carrier b and has a rigid attachment with a hub piece m<1> preferably by the engagement of teeth or grooves m<2> with the inner ends of the ratchet teeth n of the low and normal speed clutch n<1>. The extension b<2>, rigidly connected to the pawl carrier n<2>, serves as a support or bearing for the ring p, pins p<1> passing through longitudinal slots b<3> in the extension serving to secure the ring to a sleeve p<2> which in turn is coupled to the slidable sun-wheel c preferably by means of the nut c<2> connecting the sun-wheel to the slides s of the control mechanism. A sleeve c<3> shouldered at c' is rigidly secured to the gapped end of the sun-pinion, which is feathered to the axle, the sleeve p<2> being mounted upon the sleeve c<3> between the shoulder and the nut c<2>. By this means the cam-ring and the parts connected thereto are enabled to rotate with the planet-pinion carrier relatively to the sun-pinion. With the parts in the position shown, the low gear is obtained ; by moving the members p, c, j to the right till the ring j engages both the carrier b and the ring i, the direct drive is furnished, and further movement brings the ring into engagement with the ring i alone, and takes the cam-ring p from under the tails of the pawls o so that the hub is then driven at high speed. As a further modification, the arrangement on the driven side of the hub shown in Fig. 11 may be used in conjunction with the pair of clutch rings j<1>, j<2> shown in Fig. 1. According to the Provisional Specification, (1) the bearing-cone forming a guide for the bars s is rigidly secured to the axle, preferably by gapping the inner end of the cone to engage tongues or extensions of the lugs upon the axle which serve to prevent the rotation of the sun-wheel; (2) the arrangement on the driving side of the hub shown in Fig. 11 may be combined with the arrangement on the driven side of the hub shown in Fig. 1, the cam-ring p being so mounted on its sleeve that when the pawls are suppressed the ring is capable of turning with them; (3) in thearrangement employing two clutch rings j<1>, j<2>, as in Fig. 1, for the normal drive, the sun-pinion is released from the axle so that it can revolve with the other members of the train which then turns bodily. Specification No. 29,341, A.D. 1906, is referred to.