Patent GB-445657-A (GB)
Title: Improvements in and relating to friction race and roller variable speed transmission
IPC: F16H15/38
Filed: 1935-05-29
Abstract: 445,657. Variable - speed friction gearing. GENERAL MOTORS CORPORATION, Detroit, Michigan, U.S.A. May 29, 1935, No. 15618. Convention date, May 31, 1934. [Class 80 (ii)] Bifurcated carriers 80 of non-planetary friction rollers 70, in a toric-disc gear, are universally mounted at 84 on supporting spiders 12, in such a manner as to allow free rotary and tilting movement of the carriers in all directions. The joint is at one end only of the carriers, so that, under driving torque, the rollers trail freely from the joint. A reversible power-driven relay R controls the precession of the rollers by turning loose collars 110, connected by cranked links 112 to the sides of the roller-carriers 80, the connection comprising eccentrically-adjustable ball-and-socket joints 116. The provision of an inclined axis of tilt 84, 116, causes the rollers to be restored automatically to the equilibrium position after precession. The gear is arranged behind the rear-axle of a motor-vehicle and drives the bevel-pinion 46 thereof from an engine in front of the axle. An offset driving shaft 20 carries a reversing-wheel 28, adapted to be slidden into mesh with a wheel 48, secured to the final driven shaft 40, giving an invariable reversed drive. The wheel 28 carries clutchteeth 32 for direct forward engagement with those of an aligned shaft 20a, carrying a toothed wheel 22, engaging a wheel 60 which differentially drives the inner toric discs 64, through friction rollers 66. The discs 64 and wheel 60 are loose on a fixed sleeve 16, secured to the roller-spiders 12. The outer toric discs 52, 54 are drivingly connected to the driven shaft 40, the former rigidly, the latter through a torque-responsive end-loading device 58, not shown or described. The rollers 70 have limited axial freedom in their carriers. During reversed drive, the rollers process to the low gear position and are held there in readiness for the forward take-up by engagement of hooked parts 119 of the carriers with fixed collars 18. The power-driven relay R, Fig. 7, for turning the control-sleeves 110, comprises a bevel reversing-gear including a bevel-wheel 166, driven by worm-gearing 172 from the driving shaft 20a, and engaging bevel teeth on sleeves 150, 160, which are thus constantly rotated in opposite directions. Coil clutch-springs 178, 180 are so wound that, when a bridge 182, between them, is rocked by turning a rockshaft 146 in one direction or the other, they are selectively expanded into driving engagement with the oppositely-rotating sleeves 150, 160, and rock a shaft 140, connected by arms 142, 142a and links 130, with the gear control-sleeves 110. The rockshaft 146 is turned manually and by a speed-responsive control (not shown). Both clutch-springs drive yieldingly through a long initially-stressed spring 202, the clutchspring 178 being anchored to a loose sleeve 176, to which the spring 202 is connected by a rear lug 206 on the sleeve, whilst the clutch-spring 180 is anchored to a sleeve 200, having a lug 208 normally pressed against a stud 210 on the shaft 140 by the spring 200. The clutch-spring 178 drives in a direction which is counterclockwise when viewed from the right of Fig. 7, and rocks the shaft 140 directly through the sleeve 176 and the spring 202. The clockwise clutch-spring 180 turns the sleeve 200, spring 202 and then the sleeve 176, movement of which is transmitted to the shaft 140 by a lost-motion pin-and-slot connection at 192 and 184. In order to move the friction rollers 70 into the lowspeed position during reversed drive, in which the shaft 20a rotates reversely by virtue of the back-drive through the toric-disc gearing, there is a third clutch-spring 216 which automatically expands against the sleeve 160 as soon as it reverses, thereby turning the spring 202 and the shaft 140 in the counterclockwise direction. This direction would, in forward drive, move the rollers to the high-speed position, but, by virtue of the fact that, in reverse, the outer toric discs 52, 54 are driving the inner 64, the rollers precess in the opposite direction, i.e. to the low-speed position in which they remain urged against the stops 18. U.S.A. Specification 1,844,464 is referred to.