Patent GB-397875-A (GB)
Title: Improvements relating to the driving control of motor vehicles
IPC: F16H61/662
Filed: 1932-02-29
Abstract: 397,875. Controlling motor vehicles; controlling variable-speed gearing- GENERAL MOTORS RESEARCH COR. PORATION, Detroit, Michigan, U.S.A. Feb. 29, 1932, No. 6100. Convention date, March 9, 1931. [Class 79 (v).] In a motor vehicle having a continuouslyvariable speed gear provision is made for controlling the engine and vehicle speeds by a throttle or other conventional control, a control member operable by the driver and a speedresponsive device both acting on a gear-ratio control, the said speed-responsive device permitting control of the gear ratio by the driver's control only within limits dependent on engine speed. According to another feature of the invention provision is made for controlling the engine speed within one speed range both by (a) conventional means such as the throttle, and (b) a governor which automatically varies the ratio of engine speed to vehicle speed in accordance with variations in speed or load, within a second speed range by variation of the said ratio at the will of the operator independently of governor action, and within a third speed range by the automatic variation of the said ratio by the governor only. In the construction shown the engine 10 drives a propeller shaft 47 through a friction clutch, a continuously-variable friction gear having toroidal members with rollers running between, and a reversing speed gear train controlled by a hand lever 58. The accelerator pedal 70 is connected by an expanding spring link 90, 92 to the throttle 18, and by a loose spring coupling 112 to an arm or gear lever 44 controlling the friction change-speed gear. The arm 44 is also connected by a link 122 and lost-motion device 124 to a centrifugal governor 60 driven from the engine. In the position shown diagrammatically in Fig. 6, in which the engine is either stopped or idling, the accelerator pedal is held in the released position by its spring 76, the throttle is closed by its spring (not shown) and the spring 76, and the gear lever 44 is held in the low gear position by the governor 60 which acts on the lever by means of a head 128 on the rod 120 bearing against the end 126 of a casing 124 fixed to the rod 122. The spring 115 in the spring connection 112 is compressed by the action of the governor in keeping the gear lever in the low gear position. When the car is to be started the direct drive clutch of the reversing gear is engaged, the main clutch is also engaged, and the pedal 70 is rotated by the driver. In the first part of this movement the spring link 90, 92 acts as a solid link, the spring 96 being stiffer than the throttle spring, and the engine drives the car at an increasing speed. As the speed increases the governor moves the rod 120 and head 128 and allows the spring 115 to move the gear lever towards the high speed position. When the accelerator pedal has moved through about half its range the throttle is wide open and the gear lever is in the highest gear position. Further movement of the pedal compresses the spring 96 without affecting the throttle and acts through the spring 115a to move the gear lever back into the low gear position, with the result that the engine rapidly accelerates and, in spite of the lower gear ratio, drives the car faster. When the engine reaches a speed corresponding to its maximum power the head 128 of the governor rod 120 reaches the end 126a of the casing 124 and the governor moves the gear lever towards the high speed position as shown in Fig. 10, the governor altering the gear ratio so as to keep the engine at the maximum power speed. The gear lever 44 may be actuated directly by the rods 122, 110, as shown in Figs. 1, 6 and 10, or may be actuated through the fluid-pressure servo device shown in Fig. 4 in which the rods 122, 110 are connected to a valve 138 controlling the supply and exhaust of liquid to a cylinder 130 having a piston 132 connected to the lever 44. The valve 138 has an exhaust pipe 142 moving therewith, and controls ports in a slide 131 moving with the piston, the pressure inlet being at 144. When the valve is moved one side of the piston is opened to pressure and the other to exhaust, the piston being moved with a "follow-up" action until it catches up to the valve. The liquid used may be oil from the engine lubricating pump.