Patent GB-451975-A (GB)
Title: Improvements relating to variable-speed gearing for vehicles
IPC: F16H61/02
Filed: 1935-04-15
Abstract: 451,975. Controlling change speed gearing. VELO AUTOMISHUN CORPORATION, 15, Exchange Place, Jersey City, New Jersey, U.S.A. April 15, 1935, No. 11660. Convention date, April 21, 1934. [Class 80 (ii)] Relates to servo-operated change-speed gear mechanism for vehicles of the kind having a first pneumatic gear-shifting servomotor 27, Fig. 5, operated selectively by manual means for forward and reverse travel and a second pneumatic gear-shifting servomotor 28 controlled by a governor 82 responsive to vehicle speed to effect gear shifts at different speeds. Consists in providing a manually operable control, for instance a byepass valve 47, for controlling the second servomotor 28 independently of the governor and while the governor is operative to effect a shift from highest speed to a lower speed. Suction in a pipe 3 leading to the engine manifold 2, Fig. 1, is turned on to a distributing duct 33, Fig. 5, when a clutch valve 48 is turned clockwise by displacing an arm 99<1>, Fig. 4, left, which is done each time the engine clutch, not shown, is opened. To open the clutch, a shaft 6, Fig. 1, is rocked left, and this is done by depressing a pedal 7 against a spring 8, or independently by releasing the accelerator 7f. Such release moves a throttle 7e to connect a cylinder 7c to suction so that a piston 7a moves left carrying with it the clutch shaft 6 and the clutch valve 48, opening clutch and valve together. A valve 46, Fig. 5, is a manual valve for the first servomotor 27 It is controlled through a lever 66, Fig. 4, a rod 65, a rock-shaft 63, and a linkage 106, 105, Fig. 1, from a manual forward-and-reverse lever 103. When this is set for reverse, a piston 27<1>, Fig. 5, moves left and a selector bar 22, Fig. 4, moves right. When the lever 103 is set for forward, the valve 46 is turned to the position of Fig. 17. The governor 82 is not acting and a governor slide valve 45, Fig. 5, makes a connection at 721 between the distributing duct 33 and a forward-and-reverse duct 37. Suction passes through ducts 51, 49, Fig. 17, and a duct 36, Fig. 5, to the right of the piston 27<1> which moves right to first-speed position. The governor 82, Fig. 7, is driven through gearing 87, 84 from a tail shaft beyond a free-wheel tail clutch so as to be affected by the actual vehicle speed. As it expands, it thrusts a ball-ended rod 92 right against a spring 78 on the governor valve 45, a lever 96 connecting the governor and valve. As the car reaches a speed of 5 miles an hour, the governor moves the slide valve 45 downwards of Fig. 5 to second speed position so as to make connection at 68 between the distributing conduit 33 and the second speed conduit 38. The connection passes across the valve 47 at 56 and on through a bent passage 32 to the left end of the cylinder 27. When then the clutch is opened, the piston 27<1> is from extreme right sucked left, but it stops in the neutral position of Fig. 5 because then the suction is cut off from the cylinder 27 and passed on through passages 30<a> and 31 to the left end of the cylinder 28, with the result that the piston 28<1> is sucked left to bring in the second speed. On a speed of 15 miles per hour being reached, the governor valve 45 is moved to the third-speed position of Fig. 13. On opening the main clutch to bring the valve 48 to the open position shown, suction in the distributing duct 33 at 67 enters the high-speed duct 39 and after passing the valve 47, Fig. 5, at 55 enters the cylinder 28 at 41 whereby the piston 28<1> is sucked right to third speed position, and the selector bar 23, Fig. 4, moved left. At the same time a vent is opened through the second-speed passage 38 at 68, Fig. 5, through the valve 45 to admit air behind the piston 28<1> as it moves right. The car is now in high speed under control of the governor, which may reduce speed to low. Auxiliary plunger valves 61 vent both sides of both motor cylinders, when the manual valve 46 is shifted to the neutral shown by which a through common duct 35 is or may be energized. These valves are operated from the rock shaft 63, Fig. 4. The governor-disabling byepass valve 47 is moved from governor control to governor disabled position only when the car is in highspeed and it is desired to shift manually into second. By pulling a button 100, Fig. 1, a rod 101, Fig. 4, is pulled and the valve 47 turns from the position of Fig. 5 to that of Fig. 14 by which suction in the high-speed passage 39 turned on by opening the clutch is cut off from the right end of the cylinder 28 and diverted through ducts 32, 31 to the left end so that the piston 28<1> is sucked left to establish middle speed. A vent is at the same time opened at 58, Fig. 14, for the right end of the cylinder. On returning the valve 47 back to the position of Fig. 5, the governor action is resumed. Taper-point valves are provided at 111, 112, Fig. 5, to regulate the inrush of air to the high and middle speed ducts 39, 38. A retarder for the governor valve 45 is shown at 109, Fig. 4. In the second-speed position shown, a shoulder 107<1> on the valve engages a spring ball 105<1> which checks the valve in that position. At lower speed positions of the valve, the ball 1051 is inoperative in a groove 106<1>. In higher speed positions, the ball 105<1> presses hard on the valve so as to arrest its sliding motion by the governor. A preferred form of retarder for the valve 45 is shown in Fig. 20. A bell-crank 115 is connected by a spring 122 to the piston rod 28<a> of the piston 28<1>. In first speed, the piston 28<1> is as shown and the lever 115 lies across the end of the valve 45 so as to stop it in second-speed position. When the second speed is brought in, the piston 281 moves left to withdraw the obstruction 115. In third speed, the lever 115 is thrust by the compressed spring 122 hard against the under side of the protruding valve 45 so as to arrest the governor action.