Patent GB-584505-A (GB)
Title: Improvements relating to motor vehicle control mechanism
IPC: F02D39/02
Filed: 1944-05-30
Abstract: 584,505. Controlling variable-speed gearing and cutches. WESTINGHOUSE BRAKE & SIGNAL CO., Ltd. (Bendix-Westinghouse Automotive Air Brake Co.). May 30, 1944, No. 10374. [Class 80 (ii)] [Also in Group XXIX] Automatic clutch operation of a vehicle transmission is effected by pressure fluid from a reservoir 21, on a motor 16 actuating the clutch lever 7, under control of an engine speed responsive valve 5, a valve device 42 controlled by the movement of the shift rails 8, 9 of the gearbox, an accelerator-controlled valve 40, and a further valve 36 controlled by the position of the low and reverse speed shift rail 8. The speed responsive valve 5 controls the supply of pressure fluid from conduit 37, valve 36 and conduit 35 to the clutch motor 16 through conduit 39, valve 40, conduit 41, valve device 42 and conduit 43 and the exhaust from the motor to an outlet port 34, the operation being such that at low engine speed the clutch is disengaged whilst as the speed is increased the motor 16 is exhausted to engage the clutch. On operation of either shift rail 9 or 8 to effect a speed change one of plungers 85, 97 is lifted from one of the notches 92, 93, 94, or 99, 100, to open either valve 81 or 95 to admit pressure fluid from conduits 38, 106 and chamber 76 to an outlet 103 and conduit 43 to clutch-operating motor 16 to disengage the clutch. On completion of the change the plunger 85 or 97 drops into another notch to shut off the supply of pressure fluid and open the conduit 43 and motor 16 to exhaust through valves 83, 96 and ports 86, 104 to an outlet 88 and conduit 41. This conduit leads to the accelerator-controlled valve 40 which normally passes the exhaust from pipe 41 to pipe 39 leading to the valve 5 which controls the exhaust to atmosphere past valve member 31 and through opening 34 in a manner in accordance with the engine speed to give a smooth engagement of the clutch. Under certain conditions such as in reverse or low gear and full throttle the throttle rod 10, which is actuated from an accelerator pedal 15 through a hydraulic transmission, actuates the valve 40 by a cam 74 which breaks the connection between pipes 41 and 39 and exhausts the former directly to atmosphere through a port 70, thus rendering the valve 5 ineffective and ensuring that the clutch is kept fully engaged and not allowed to slip. The valve device 36 is provided to render the speed responsive valve 5 ineffective under certain other conditions, namely, neutral and second and third speeds. This is accomplished by a plunger 54 engaging in a notch 108 in the shift rail 8, when this rail is in the position corresponding to' the above three conditions, and closing a port 49 from pressure conduit 38, 37 to pipe 35 leading to the valve 5 and opening this pipe to atmosphere through a port 53 and outlet 58. Thus, when the engine is idling in neutral or running slow in high speed ratios, the member 30 of valve 5 opens to allow exhaust of the motor 16 through valve 36 to ensure the clutch remaining engaged and not tending to slip. Specification 520,587 is referred to.