Patent GB-543981-A (GB)
Title: Clutch and change speed transmission operating mechanism
Filed: 1940-09-14
Abstract: 543,981. Fluid-pressure servomotor control systems. BENDIX AVIATION CORPORATION. Sept. 14, 1940, No. 14196. Convention date, Sept. 15, 1939. [Class 135] [Also in Group XXIV] A control for motor vehicles includes a fluid pressure servomotor-actuated friction clutch, manual means for introducing low and reverse gears and fluid-pressure servomotor means for introducing second or high gears, the gear servomotor being operated by means controlled by the clutch servomotor and by a governor mechanism which is responsive to the vehicle speed, and which also serves in part to control the operation of the clutch servomotor. The transmission can thus be placed in second gear or in high gear according as the speed of the vehicle drops below or exceeds a pre-determined value. In the gear-box 10, Fig. 1, embodying a second and high gear shift rail and a low reverse gear shift rail, the crank 12 operates the shift rail selecting mechanism and the crank 14 moves the selected speed gear into operation. Movement of a handle 48 in the plane of the handwheel 52 operates the crank 14 and movement perpendicular to the handwheel 10 operates the crank 12, the movements being transmitted through links 30, 53. The crank 14 is also power operated by a servomotor 27 which is connected by pipes 236, 212, to the intake manifold 178. The motor 27 is controlled by valves operated by solenoids 90, 92. A friction clutch lever 22 is operated by a footlever 20 or bv a servomotor 24 having a connection 210, 212 with the intake manifold 178 controlled by a valve 174. The latter is actuated by a solenoid 188, Fig. 5. The electrical circuits comprise an earthed battery 102, Fig. 9, an ignition switch 104, a cut-out switch 106, a clutch operated switch 108, a switch 110 actuated by handle 48, a solenoid 90 and a power-operated switch 112. The solenoid 92 is in parallel with the solenoid 90 and its circuit includes a switch 114 operated by a speed governor 116. The circuit for the solenoid 188 includes a cut-nut switch 190, switch 192 operated by the accelerator 194 and a switch 196 opened by the second and high gear shift rail only when the transmission is in high gear. In operation assuming that the engine is idling, the switches 104, 106, 190 are closed, the accelerator 194 is released thereby closing switch 192 the switch 110 is closed as the handle 48 is spring biased to its second and high gear position, and the switches 196 and 112 are closed. The solenoid 188 is thus energized and the piston 214 of the servomotor 24 moves to the left to move the lever 22 to disengage the clutch and to close switch 108. The circuit of the solenoid 90 is thus closed and the piston 26 of the motor 27 moves to the left, Fig. 1, to rotate the crank 14 and place the transmission in second gear. The accelerator 194 is then depressed to speed up the engine, open the switch 192, and engage the clutch. When the speed reaches a pre-determined amount the governor 116 moves the contacts 140, 144 into engagement making possible high gear operation. To move the transmission into high gear, the accelerator is released to close the switch 192 to operate the solenoid 188, disengage the friction clutch and close the switch 108. The solenoid 92 is thus energized and the piston 26 of the motor 27 is moved to the right to place the transmission into high gear. At the same time the switch 112 is opened and the solenoid 90 is de-energized. The accelerator is now depressed to engage the clutch and speed up the vehicle. When the vehicle is travelling above a pre-determined speed release of the accelerator will not effect clutch dis-engagement as the switch 196 is open when the transmission is in high gear. The valve 174 for the servomotor 24 is provided with a spring-pressed member 260 having large and small apertures 254, 280 which can register with a hole 256 leading to the atmosphere. When the servomotor piston 214, Fig. 5, moves to the right to effect clutch engagement the suction pressure in the pipe 202 first brings the holes 254, 256 into register and the initial clutch engaging movement is rapid. As the pressure in the pipe 202 increases, the hole 280 registers with 256 and the clutch-engaging movement is slowed down. In the arrangement shown in Fig. 1 a fluid clutch 16 is placed between the engine and the friction clutch.