GB448776A - Improvements in transmission mechanisms - Google Patents

Abstract

448,776. Variable-speed friction gearing. SHARPE, J. S., Haverford, Pennsylvania, U.S.A. Oct. 15, 1934, No. 29458. [Class 80 (ii)] In variable-speed gearing of the toric disc type, precessional rollers 63, 71, Figs. 1 and 2, carried round by a driving-shaft 4 roll between fulcrum discs 86, 87 and a transmission disc 85, and there are a toothed planetary train 96, &c., a one-way brake 124, and a torque screw 2 so that changes between geared drives vary automatically with torque and changes between geared driving and solid driving are automatic and without the use of any clutch. The shaft 4 drives through the torque screw 2 to the spider 34 of a first set of planetary rollers 63 and through a rotary drum 44 to the spider 43 of a twin set of rollers 71. The controls 57, 79 of the two sets of rollers are interconnected through a light relatively-turning drum 56. The outer or fulcrum discs 86, 87 are splined at 91 and secured at 88 respectively to a revoluble connecting drum 27 there being tractionpressure producing springs at 92. A cranked fulcrum member 99 supporting the toothed planetary cluster 96 is secured at 101 to the disc 87 so that a combined fulcrum member 86, 87, 99 triple in character turns with the drum 27. The double transmission disc 85 through a shaft 93 and pinion 95 drives the planet cluster 96 comprising elements 96a, 97, 98 which turns loosely on the fulcrum 99. The gear 97 is operative during reversed drives only. The pinion 98 constantly engages an internal gear 107 rigid with a, driven aligned shaft 108. The reaction of the load upon the fulcrum 99 is reverse to the direction of drive of the shaft 4, which carries the rollers with it. Thus the load reaction thrusts the fulcrum discs 86, 87 round backwards while the planet rollers 63, 71 pull these discs forwards. If the load is small, the forwards pull of the rollers prevails and the gearing turns solid in top speed. As the load increases, the fulcrum discs 86, 87 are held back against the rollers' pull, and geared drives come in which are varied automatically by the torque screw 2. The drive is cushioned by a spring 132 which allows the triple fulcrum member 99, 86, 87 to yield rearwardly threefourths of a revolution while a pin 134 travels round in a groove 135, Fig. 5, while the spring 132 is being stressed. The one-way brake 124, Fig. 4, is arranged between a flange 117, Fig. 1, on the triple fulcrum member 27 &c. and a ring 122 which is connected by a dog clutch 127 to the spring 132. To effect reversed driving, the one-way brake 124 is disabled by disconnecting the clutch 127 by a rock-shaft 138 and at the same time engaging a dog brake 105, Fig. 2, with an annulus 102 by a rock-shaft 143. The torque screw 2, Fig. 1, which is adjustable by a spanner applied to a spindle 19, acts by sliding axially a rod 47. The rod 47 carries a pin 49 which projects through a straight slot 51 and through a helical slot 52 in a superposed sleeve 53. The sleeve 53 is thus displaced angularly to initiate precession in the rollers 63 of the first set and through the drum 56 and sleeve 79 causes the rollers 71 of the twin set to follow the first. The sleeve 53, Fig. 8, carries rigidly inclined guides 58 in each of which slides a block 59, Fig. 1, engaged by the ball end 61 of an arm 62 projecting from the roller which is ball-snpportod at 69. Angular displacement of the sleeve 53 starts the precession which as it proceeds causes the block 59 to slide along the inclined guide 58 with the result that the precession is terminated in a new stable gear position of the rollers. The twin rollers follow always. Thus the torque screw 2 effects the changes between the geared drives and assists the change into solid drive which is without a clutch but is aided by internal. friction in the gearing. Lubrication is effected by rotary scoops 77, Fig. 6 (not shown). As applied upon a vehicle, an automatic clutch is arranged between the shaft 4 and the engine.