GB534691A - Improvements in or relating to control systems for motor vehicles - Google Patents

Abstract

534,691. Variable-speed gearing. DERUNGS, E. A. Sept. 11, 1939, No. 25543. Convention date, Sept. 10. 1938. [Class 80 (ii)] In a control-system for motor vehicles having a variable-speed gear, a fluid-operated retarding-device, which is automatically adjusted in accordance with the setting of the gears, is employed for varying the time occupied in the disengagement and re-engagement of the driving-clutch and in the changing of the gear. A longer time is taken in changing from a lower to a higher gear than vice' versa, in order to avoid shocks and loss of speed. In the arrangement described, the clutch C of the motor A, and a two or more speed gear contained in a box B, are operated by a sliding rod 20, which is moved in one direction by an electromagnet 18 and is controlled by a dashpot 26, the fluid passage of which is varied in size according to the change of gear to be made. The circuit of the magnet 18 is completed by a commutator, which is adjusted by the driver, and also selects the required gear and opens or closes the throttle-valve 2 of the motor. The two-speed gear is operated by two sliding rods 6, 7, to which are pivoted rods 10, 11 connected by a cross-bar 15. The desired gear is selected by one of two electromagnets 12, 13 the circuit of which is made by the commutator. The magnets are carried by a sliding frame 14, which is operated by a lever 22 from the rod 20. The operative magnet attracts the cross-bar 15. which is rocked by the frame 14 and moves one of the rods 6.7 in a direction to change the gear. The clutch is disengaged by a lever 5 connected to the rod 20. The shaft 35 of the throttle-valve 2 is turned in one or other direction by one of two electromagnets 29, 30. the circuit of which is also made by the commutator. To the shaft 35 is connected a rotary valve 53, which is connected by a pipe 52 with the aperture 27 of the dashpot 26. The valve 53 controls a series of openings 58. by which the admission of air to the dashpot is varied. so as to retard more or less the movement of the operating-rod 20. The accelerater-pedal 3 has a yielding connection with the shaft 35 of the throttle-valve, so that the automatic actuation of the valve is independent of the pedal. At the end of the travel of the frame 14, the circuits of the magnets are broken, and the rod 20 is returned to its upper position by spring action. This movement effects the re-engagement of the clutch, the speed of which operation is determined by a second rotary valve 61, which is adjusted by the cross-bar 15 of the gearchanging mechanism. The valve 61 is connected to the dashpot by a pipe 64, and controls the emission of air during the upstroke of the rod 20. A third valve 66 enables the initial resistance of the dashpot to be adjusted by hand.