Patent GB-450052-A (GB)
Title: Improvements in variable speed transmission mechanism
Filed: 1935-06-27
Abstract: 450,052. Controlling variable speed gearing. HILL ENGINEERING CORPORATION. 901, Mutual Building, Richmond, Virginia, U.S.A. June 27, 1935, No. 18421. Convention date, June 28, 1934. [Class 80 (ii)] In a motor vehicle, each disengagement of the main-clutch 18 operates a selector-valve 59, controlling a double-acting fluid-pressure motor 51, so as to establish second and high speeds successively. The motor 51 is directly connected by a resilient piston-rod 55 and balljoint, to a conventional shifter-lever 20, transverse selection movements of which are effected manually only, there being a permanent spring bias towards the channel for second and high speeds. The main-clutch 18 is operated by a fluid-pressure motor 26, which, like the gear-shifter motor 51, is automatically energized with engine-suction, each time the vehicle accelerator-pedal is released. Speedomotercontrolled means are provided whereby the automatic declutching and change from high to second speeds cannot take place whilst the vehicle is travelling above a predetermined speed of, say, 8 m.p.h. Various manual controls are provided for overriding the automatic action and also for providing for automatic clutch release, but not gear-change, in high gear above the predetermined speed referred to. The supply of engine-suction to the clutch actuator 26 and the shifter-cylinder 51 is controlled by a common valve 31, which is opened by a cam 46 on the engine-throttle spindle 13 when the accelerator-pedal is released. A solenoid-valve 41 is arranged between the source of suction and the valve 31, whereby when the solenoid-valve is de-energized the suction is completely cut-off. The valveassembly 31, 41, 46 is fully described in Specification 449,545. The supply of suction or atmosphere to alternate sides of the shiftercylinder 51 is controlled by the three-way selector-valve 59, which is turned through a quarter of a revolution, always in the same direction, every time the main-clutch disengages. Such rotation is effected by a spring- loaded finger 126, on the clutch-rod 29 and adapted to engage, in one direction only, one of four arms 107 projecting from the valvemember 59. A spring-loaded check-valve 63 in the inlet-conduit of the valve 59 ensures complete clutch disengagement before the gears are shifted. For manual operation of the shifter-lever 20, both sides of the shifter-cylinder 51 are vented to atmosphere and-suction cutoff, by a simple valve 116, operated by a solenoid 121. In order to provide for operation of the main-clutch without necessarily operating the selector-valve 59, the radial arms 107 of the latter are spring-mounted and can be retracted laterally from the path of the operating-finger 126, by energizing a solenoid 112, operating a frame 114, surrounding the two lower arms. In order to prevent automatic clutch -disengage - ment and gear-shift at speeds above the prodetermined 8 m.p.h. in high-gear, the shiftercylinder 51 controls a two-way throw-over switch 152, which, in the high-speed position shown, energizes the main solenoid-valve 41, only through the speedometer-made contacts 144, which break above 8 m.p.h., thereby cutting-off all suction. In second-speed, the switch 152 is thrown over to a circuit which shunts the speedometer-contacts 144, thereby permanently energizing the solenoid 41 and providing suction for automatic action at all speeds. For complete manual operation and for use of first-speed and reverse, the following means are provided. A contact 136 on the knob of the shifter-lever can be completed when the latter is grasped, thereby energizing the solenoid 121 and venting both sides of the shifter-cylinder 51. When the shifter-lever is moved laterally against the spring-bias into the low-speed and reverse channel, its lower end completes contacts 22<1>, which also energize the solenoid 121 and permit release of the contact 136. The contacts 22<1> also energize the solenoid 112, which retracts the fingers 107, permitting actuation of the clutch without the selector-valve 59. For complete manual operation of the shifter-lever the solenoid 121 may also be energized by a switch 141. In order to provide for automatic clutch disengagement on release of the accelerator-pedal under all conditions in low-speed and reverse, the shifter rail 158 of these speeds, when in either operative position, completes contacts 162, which permanently energize the main-solenoid 41 controlling the supply of suction. If the vehicle were to be brought to a standstill and the engine stopped in high speed, the disengagement of the clutch changes the gear to second speed, and the subsequent disengagement of the clutch to start the vehicle would send the gear back to high speed for the start. In order to prevent such undesirable change back to high speed, a switch 172 is closed manually to energize the solenoid 112 which retracts the fingers 107 of the shifter-valve 59 from the path of the clutchfinger 126. As soon as the engine is restarted, the switch 172 can be released. There is a further switch 166 to provide automatic clutch disengagement on release of the acceleratorpedal at all speeds in high gear, the switch permanently energizing the main-solenoid 41 and the solenoid 112, the latter thus preventing a gear change at the declutching.