Patent GB-417648-A (GB)
Title: Improvements in means for controlling driving gear of automobiles
IPC: F16H61/30
Filed: 1933-02-04
Abstract: 417,648. Controlling variable speed gearing. BENDIX AVIATION CORPORATION, 105, West Adams Street, Chicago, U.S.A. Feb. 4, 1933, No. 3473. Convention date, Feb. 6, 1932. [Class 80 (ii).] In a motor vehicle having main and auxiliary change-speed gears, each change-speed gear is controlled by a separate servo-motor and the two servo-motors are controlled by a single member. The servo-motors are preferably of the vacuum type energized, when required, by the release of the accelerator pedal, the main clutch being simultaneously disengaged by another servo-motor also energized by the release of the accelerator pedal. In the construction shown, the engine 20 is connected by a clutch 42 and propeller shaft 44 to a gearbox 84 mounted on the chassis frame, the road wheels 36 being driven from the gear-box through shafts 38. The propeller shaft drives a shaft 104 through the main two-speed and reverse gear 88, 92, 96, 112, and the shaft 104 drives a free-wheel or locking differential gear through the auxiliary two-speed gear comprising bevel pinions 210, 212 in constant mesh with bevel wheels 214, 216, and slidable clutches 228, 220 controlled by a lever 226. The clutch 42 is controlled by a servo-motor 52, and the main and auxiliary gears by servo-motors 126 and 232 respectively, the piston of the servo-motor 232 being connected to the lever 226 of the auxiliary gear. The clutch servo-motor is connected to the engine induction pipe 22 by a pipe 76 and is controlled in known manner by a valve connected to the accelerator pedal 30, so that when the accelerator pedal is released the clutch is disengaged. The main servo-motor 126 is connected by a pipe 138 to the clutch servo-pipe 76, so that this servo-motor is also energized whenever the clutch is disengaged ; thus the gear is changed if the servo-motor is set for a change of gear. The auxiliary servomotor 232 is connected by a pipe 236 and a valve 256 to the clutch servo-pipe 76, the valve 256 being operated when desired, by the driver's heel acting on a pivoted arm 266 situated just below the accelerator pedal. In its normal position, as shown in Fig. 5, the valve connects the auxiliary servo-motor to atmosphere through the pipe 236 and a port 268, but when the heel piece 266 is depressed the valve closes the connection to port 268 and connects the pipe 236 to a pipe 76<1> connected to pipe 76, so that the auxiliary servo-motor also is energized when the accelerator pedal is released and the main clutch is disengaged. The auxiliary servo-motor is constructed as described in Specification 416,444, [Group XXVIII], and operates the auxiliary gear as described in Specification 416,407, the arrangement being such that each time the servo-motor is energized its piston moves from whichever end it occupies to the other end, and changes the gear from high to low or low to high without any selective action by the driver. The main gear servomotor 126 is controlled by a valve 140, a Bowden mechanism 142, 144, and a selector handle 150. When the main gear is to be changed, the lever 150 is moved to the new gear position and moves the valve 140 accordingly. The accelerator pedal is then released, the clutch is disengaged, the servo-motor 126 is energized and the piston 124 " follows up " the valve 140 to effect the desired gear change. In a modification the gear lever is connected to the piston 124 through a lost-motion connection, this lost motion being used to operate the valve controlling the servomotor. If the power fails the gear lever actuates the piston directly, when the lostmotion has been taken up. The inter-connection of the clutch and main servo-motors, and the construction of the main servo-motor, are described but form part of the subject of Specification 419,102. The Specification as open to inspection under Sect. 91 comprises also part of the subject of Specification 419,102. This subject-matter does not appear in the Specification as accepted.