GB533660A - Improved control mechanism for variable ratio gearing - Google Patents

Abstract

533,660. Variable-speed gearing. GENERAL MOTORS CORPORATION. Oct. 12, 1939, No. 27703. Convention date, Nov. 9, 1938. [Class 80 (ii)] In variable-speed gearing in which a positive coupling of some of the trains is effected with the aid of synchronizing friction-clutches, a lever arm for shifting the gears is so formed as to impart a relatively slow and powerful movement to effect the engagement of the synchronizing-members, and a quicker and less powerful movement to effect the positive engagement. The invention is described as applied to a known type of gearing, in which a gear 12, Fig. 1, on the driving-shaft, or a wheel 22 geared thereto, can be connected to the driven shaft 20, which is contained within the driving-shaft, by a slidable toothed coupling-member 30 splined on the driven shaft. The coupling-member is adapted to engage with internal clutch-teeth 18, 24 on members carried by the driving gears 12, 22 in order to give the second and third speeds. The low speed and the reverse are obtained from a gear 36 rotating with, and slidable on, the coupling-meinber 30, the gear being driven in either direction from a counter-shaft. Coned friction-members 14, 28 carried by the gears 12, 22 can be engaged by floating friction clutchrings 50, 60 connected to the coupling-member 30, and having a lost-motion connection with the driven shaft. The coupling-member is shifted in one or the other direction, to give the second and third speeds, by an arm 82 on a sliding rod 84, the friction clutch-members being engaged before the positive engagement is effected. An arm 88 on a sliding rod 90 shifts the gear 36, to give the first speed and the reverse. The rods 84, 90 are shifted by crankarms on a shaft 100, Fig. 3, which is under the control of the driver, and is movable endwise to engage either crank-arm with its rod. The arm 102, that shifts the rob 84 controlling the second and third speeds, has a cam-shaped end 104 formed with a convex portion near the axis of rotation, for effecting a slow forceful movement to engage the synchronizing-members, the outer end of the cam imparting a quicker and less forceful movement to effect the positive engagement. The arm that shifts the rod 90 for first speed and reverse has a cam-shaped end of uniform curvature.