GB532496A - Power transmission mechanism for motor vehicles - Google Patents

Abstract

532,496. Variable-speed gearing. GENERAL MOTORS CORPORATION. Sept. 1, 1939, No. 25107. Convention date, Sept. 1, 1938. [Class 80 (ii)] Power transmission mechanism for motor vehicles comprises two gear mechanisms providing alternative driving ratios and each including a servo-operated clutch, the mechanism providing the lower gear ratio incorporating a hydraulic coupling, and the clutches being controlled by a speed-responsive device which selects the higher gear ratio above a pre-determined speed and the lower gear ratio below that speed. As shown, the engine shaft 1, Fig. 2, drives a gear-box shaft 2 carrying clutch members 4, 6, of clutches D, C, respectively The member 4 may be clutched to a gear 10 driving the pro. peller shaft 60, and the member 6 may be clutched to a hollow shaft 34. The latter may drive the gear 10 through a hydraulic coupling T and a one way clutch 18 for a forward drive, or through the coupling T and gearing 16, 32, 27, 28, 26, 23, for reverse driving, depending upon the position of a slider 25 movable by fork 95. The slider 25 may also be placed in a neutral position. The clutch D embodies synchronizing means. The clutches D, C, are operated by compressed air servo-motors M1, M2, the air supply being controlled by an electrically operated valve V, Fig. 9. When the solenoid 175 of the valve V is energized, compressed air passes through the pipe 124 to the cylinder 130 of the motor M1 to throw in clutch D, and then through pipe 122 to cylinder 125 of motor M2 to throw out clutch C. A speed governor G, switches S<1>, S<2>, S<3>, and a solenoid 155 associated with the carburetter throttle arm 151 are electrically connected to a battery B, and the solenoid 175. In operation when the speed exceeds a pre-determined limit, the sleeve 170 of the governor G makes contact at 176 to energize the solenoid to operate the clutches. During the movement, the arm 185 of switch S<2> is in the position shown in Fig. 9 and the solenoid 155 is energized to reduce the engine throttle to idling position to assist in the synchronization action of the clutch D. At the end of the movement the arm 185 is rocked by the shaft 71 to restore the engine throttle to the control of the driver. The accelerator rod 154 which is connected to the carburetter level 151 by a lost motion device 158 has a stop 165 thereon. This stop 165 will move the armature 180 over to the contact 178 when the engine throttle pedal is moved past full throttle position, resulting in energization of the solenoid 175 and down shift from direct to converter drive. Movement of the slider 25 is controlled by a lever 100 embodying a switch S<3> controlled by a button 198. Upon depression of the button 198 the solenoid 175 is energized, and the converter unit T is temporarily relieved from the drive to facilitate the shift of the slider 25.