GB448356A - Improvements in or relating to change-speed gearing - Google Patents

Abstract

448,356. Controlling change-speed gearing. ALBION MOTORS, Ltd., South Street, Scotstoun, and FULTON, H. W., 16, West Chapelton Crescent, Bearsden, both in Glasgow. Feb. 23, 1935, No. 5863. [Class 30 (ii)] Relates to controlling-means for change-speed gearing 1, Fig. 1, for motor-vehicles of the kind in which there is a manual preselector 22<1> and an executive control 4 operated by a fluid-pressure servomotor 2. The gearing 1 is of the type comprising epicyclic drums to which brakes are applied after selection when the lever 4 is released or allowed to be swung right by return springs, not shown, in the gear box. The servomotor 2 is rendered operative by a valve 6 which is opened to effect the brake-releasing stroke of the executive control 4 by the clutch-opening stroke of a main clutch pedal 7 and which valve 6 is subsequently closed to permit the return stroke of the control 4 in brake - engaging direction by the servomotor 2 independently of the clutch pedal 7. The valve 6 is connected to the pedal 7 through a two - part link 8, 8<a >pivoted to an arm 9 carrying a ratchetcam 11 presenting a step 12 engaged by a pawl 13 pivoted upon the lever 7 and held down by a spring 14. When it is desired to change after preselection, the pedal 7 is depressed. The pawl 13 pulls the link 8 after it and, as a quick-throwover lever 17 passes its dead centre, the valve 6 is shot from its closed position of Fig. 1 to its open position of Fig. 3. Suction in a reservoir 22 is communicated to the left side of a piston 3 which is sucked to and past the position of Fig. 3, by which the brakes in the gear-box 1 are all released. An arm 15 rigid with the pedal 7 has tripped up the pawl 13 so that the valve 6 is free to move independently of the pedal 7. In the partial stroke position of Fig. 3, a striker 21 on the piston rod 5 engages a striker 20 on the link 8a so that as the leftward piston stroke is completed, the lever 17 is carried over its dead centre leftwardly. The valve 6 is thus shot to its closed position opening the cylinder 2 to the atmosphere at 23 and the gear-box return springs bring the executive control 4 back to the position of Fig. 1 with the selected gear brake in engaged position.