Patent GB-497478-A (GB)
Title: Automatic control means for vehicles
Filed: 1937-03-18
Abstract: 497,478. Controlling variable-speed gearing. DERUNGS, E. A. March 18, 1937, No. 7939. [Class 80 (ii)] Relates to control apparatus for variablespeed gearing for motor vehicles of the kind in which the main clutch and the gearing are actuated automatically during gear change by electrical relays controlled by a member of which the position is determined by the speed of the vehicle and by the position of the accelerator pedal. Alternative semi-automatic control is provided. The controlling member or arm 75, Figs. 1a and 8, is secured on a shaft 104 and engages in succession with first, second, and third gear switch-plates 77, 77<1>, 77<11>, each carrying mercury tube switches such as 78, 79, Fig. 9, which are thus rocked to make the necessary circuit changes. The position of the arm 75 is determined by a governor 99 operated from the speedometer cable &c. and by a linkage 110, 108, 106 connected by a rod or cable 27, Fig. 1, to the accelerator pedal 24. The governor adjusts a nut 101 axially on a quick-pitch screw on the shaft 104, the nut being guided in a casing 103 which is rotated, to produce an auxiliary rotation of the arm 75, by the pedal 24, which is coupled to the hand and foot brake levers 9<1>, 16 and to the casing 103 in such manner that application of the brakes produces a return movement of the arm 75 towards the neutral position, while depression of the pedal 24 at first advances the arm 75 but towards full throttle returns it, the gear selected thus suiting itself, for example on hills, to the power requirements. The main clutch is operated by a lever 30, Fig. 1, controlled for engagement by a dashpot 34, and is disengaged by a rod 15, when the brakes are applied, but normally by a rod 33 linked with play to a lever 40 which is operated by lever 48 from an electromagnet 46 controlled by a relay 87, Figs. 1 and 8, the lever 40 moving, if desired, with spring interconnection, with a lever 50 actuating a frame 60 which is thus lowered to engage the gear which has been selected by excitation of coils 61, 611, 61<11>, or 61<111>, Figs. 1, 2, and 8. When a coil, say 61<1>, is excited, a rocker 63<1> pivoted on the frame 60 is swung outwards to position 65<1>, carrying with it a rocker 63 linked to it by a rod 67. When the frame is lowered, the rocker 63<1> moves a gear-shifting lever 72 to the operative position shown. On breakage of the circuits of the coil 61<1> and magnet 46, the frame returns under the action of the spring 74 and the rockers are returned to central position by springs 68, 68<1>. On further movement of the frame 60, for neutralizing or for gearchanging, either centralized rockers return previously-actuated levers 72 or 71 to neutral position or a projecting rocker returns the lever through neutral to the other operative position. Four rockers 63, 63', 63<11>, 63<111> are employed, and the rod 67 is extended to overlap with play the rod 67<1> connecting the rockers 63<11>, 63<111>. Both rods carry projections 52, Fig. 3, co-operating with grooves in a central loose disc 53 to prevent undesired simultaneous movement of rockers. A hand-controlled contact arm 56, Fig. 8, is set to the position shown for automatic forward-speed control, to the position to engage plates 57<111>a and 57<111>b for a reverse speed similarly effected, and to position 57<1>a ... 57'e for semi-automatic control in which a series of push-buttons are employed to connect battery points 96 ... 496 alternatively with points 95, 97 ... 495, 497. This semi-automatic control gives three forward speeds, neutral, and reverse and excludes the automatic action of the control arm 75 and switch plates 77 ... 77<11> now described. The arm 75 during movement anticlockwise, Fig. 8. strikes a lug 76 on the first-speed switch, which is thus turned through 90‹ on its adjustable centre pivot 149, at first passing part only of the mercury in the tube 78 to the other end through a constriction 80, but the whole of that in tube 79 to the other end, and thus closing circuits to excite the coils 61 and 87 and thus select and establish the first speed. When the whole of the mercury in tube 78 has passed to the other end, the circuits are broken and the frame 60 returned to its raised position. Similar actions occur when the arm 75 advances to connect the second and third gears, but the switch tubes carry contacts (not shown) which temporarily cut off the ignition or reduce the fuel to facilitate gear engagement. On reverse movement of the arm, the switch plates 77<11> ... 77 are returned in succession and the switch tubes carry contact studs advancing the throttle to assist gear change. Finally, the relay 87 only is excited to return the gears to neutral. For starting, a limited depression of the accelerator pedal is effective to move the arm 75 to institute first speed, either forward or reverse, according to the setting of the contact arm 56. An emergency control-pedal 45 is spring-connected to the lever 40.