GB412681A - Control of change-speed mechanism for motor-vehicles - Google Patents

Abstract

412,681. Controlling change speed gearing. M.G. CAR CO., Ltd., and COUSINS, H. E. C., Pavlova Works, Abingdon-on- Thames. Feb. 13, 1933, No. 4331. [Class 80 (ii).] Comprises in the drive of a motorvehicle the combination of change-speed transmission mechanism 2, Fig. 1, wherein various preselected speeds are brought into action alternatively by friction means on the actuation of a main gear control 4, with a main friction clutch 5 between the said mechanism 2 and the engine 6, such clutch being released by servo means controlled automatically either by, or from, the said main gear control 4, or by the accelerator or other engine control. Specifications 328,660, [Class 80 (ii)], and 370,442 show change-speed mechanism of this kind wherein the main gear control is a pedal mounted in the place usually occupied by the clutch pedal, the release of which pedal applies a preselected brake so as to bring in the corresponding gear ratio. Thus a speed in such mechanism in a gear-box 2 which has been preselected by moving a lever 3, is brought into action by releasing the main gear control pedal 4. According to this invention, a main friction clutch in a casing 5 between the gear-box 2 and the engine 6 is servo-released on depression of the pedal 4 which precedes the release. The depression thrusts a valve 8, Fig. 2, to the right so as to connect the cylinder 9 of a servomotor to engine suction in a pipe 11. A piston 12 is thus sucked to the right so as to turn a lever 13 to the left and so disengage the clutch 5 against its spring, not shown. In a modification, an auxiliary pedal is arranged over or in front of the main control pedal 4 so as to be moved before the pedal 4. This auxiliary pedal operates the control valve 8 or electric contact of the servomotor. In the arrangement of Fig. 3, the main clutch 5 is released by fully releasing the accelerator pedal 15. To change, say, from second to third speed with this arrangement, after the preselector lever, not shown, has been set, the driver releases the accelerator pedal 15 so as to open the main clutch 5, and then presses and releases the main gear control pedal, not shown, whereupon the drive is taken up on the new speed as soon as the accelerator pedal 15 is again depressed.