GB326041A - Improvements in variable-speed gearing - Google Patents

Abstract

326,041. Banker, O. H. March 25, 1929. Variable-speed epicyclic gearing; clutches, friction.-In speed gearing for motor vehicles of the kind comprising a plurality of sets of reduction gearing each controlled by a separate centrifugal governor, which governors operate successively to render the corresponding sets inoperative and so change the gear ratio, the movements of the governor weights under centrifugal action are prevented until a predetermined speed is attained. The driving shaft 16 carries a sunwheel 25 gearing with planet wheels, 26 turning in a carrier 29 and each integral with a wheel 33 gearing with a sun-wheel 34 on a loose sleeve 36. The sleeve carries a sun-wheel 37 forming part of a second similar epicyclic gear 37, 38, 39, 29<1>, 40, the latter wheel on a loose sleeve 42 formed with a clutch end 43 engageable with a clutch part 44 splined on the driven shaft 18 and controlled by a slidable member 45. The part 44 is moved to the left, for direct forward drive between the sleeve 42 and shaft 18, and to the right for reverse drive through gearing 53, 52, 54, 55, 56 by a lever 125 and linkwork from a lever 111 carried on the steering column. Each set of planet gears is prevented from backward rotation, so as to act as idlers on stationary axes transmitting a reduced drive, by one-way roller detents comprising spirally-wound spring-steel rollers 57 mounted on pins and pressed to locking position between a stationary cylindrical ring 58 and cam surfaces 59 on the carrier 29 or 29<1> by spring-pressed levers 63, which carry weighted arms adapted under centrifugal action to remove the rollers from contact with the ring when action is taken resulting in rotation of the planet carrier. The carriers may alternatively be geared to shafts controlled by one-way detents. The detents act, further, to prevent back running of the vehicle on an incline. Plate clutches 69, 70 are arranged between the planet carrier 29 and the sleeve 36 and also between the carrier 29<1> and the sleeve 42 and are normally disengaged, but are brought into action by spring-controlled centrifugal weights 80 turning with the sleeves and bearing upon levers 74. The parts are so constructed that on increase of speed of the driven shaft 18 the carrier 29 is clutched, so that its gear becomes solid, and that at a higher speed the carrier 29<1> is clutched, so that there is a solid drive throughout between the shaft 16 and sleeve 42. Spring detents prevent movement of the weights at intermediate speeds of rotation. In each planetary gear the centrifugal weights 80 are provided with lateral rack teeth engaging a central pinion 96, which may be prevented from free rotation by a clutch 99, the teeth of which are so formed that only when the weights are fully withdrawn or freely expanded may they be locked in position for solid or for reduced drive. Operating- gear is provided to lock either the left-hand gear alone or both gears in either reducing or solid drive state. In order that the engine may be used as a brake, the planet carrier 29<1> may be locked to the casing 19 by a positive brake. The operating levers 101, 100 of the clutches 99 are the one secured to a sliding rod 129, Fig. 15, and the other loose and adapted to be engaged by a shoulder thereon. The lever 100 is operated by levers 136, 138 and linkwork from a plunger 149 on the instrument board, while the lever 101 and the rod 129 are similarly operated by a lever 155 and linkwork from the plunger 164. The rod 129 also carries one member of the brake which locks the planet carrier 29<1> to the casing. The end of the rod is engaged by the lever 125 when the reverse drive is engaged, so that both planetary gears are locked in the reducing state during reverse.