Patent GB-681952-A (GB)
Title: Improvements in semi-automatic speed changing device
Filed: 1950-10-19
Abstract: 681,952. Variable-speed gearing. CHAMBONNEAU, R. Oct. 19, 1950 [Oct. 28, 1949; March 21, 1950], No. 25535/50. Class 80 (ii). Manipulation of the gear lever 1 of a motorvehicle closes a normally-open switch in the end knob 3 of the lever to energise an electromagnet 4, Fig. 3, whereby a valve 39 is drawn leftwards to apply suction from the engine intake manifold 1a through pipes 17, 18 to a servomotor 19 to disengage the main clutch. When the lever 1 is released, the clutch gradually engages and the throttle is opened, in one arrangement on depression of the accelerator 16 and in a second arrangement automatically. In the first arrangement shown in Fig. 1, the valve 39 is locked open by a spring-loaded pin 47 engaging an annular groove 46, and a flexible branch 24 from pipe 18 leads to a cylinder 8, Fig. 5, housing a piston 56, the lower end 8a of the cylinder 8 being linked to the accelerator 16 while the upper end 9 of the piston rod 57 is linked to the throttle 11. The piston 56 is urged upwards relative to the cylinder 8 by a spring 64 within the cylinder and springs 61, 62 in series between a collar 59 fixed on the rod 57 and the top of the cylinder, a slidable collar 60 being interposed between the springs 61,62. The collars 59, 60 constitute a normally-open switch controlling an electromagnet 6, Fig. 3, adapted to withdraw the pin 47. When the valve 39 is opened by manipulation of the lever 1 to energise the servo 19, suction is applied also to cylinder 8, tending to shorten the distance between points 8a and 9. If the accelerator has been released, the throttle remains closed and the accelerator remains in released position due to its return spring. On depressing the accelerator, after release of the lever 1, cylinder 8 moves upwards but the suction therein maintains the throttle closed until the contacts 59, 60 close to energise the magnet 6 and withdraw the pin 47. The valve 39 then moves rightwards under suction influence to shut off the suction from pipe 18 and open the latter to atmosphere via an adjustable bleed opening 48. The clutch now engages gradually and the throttle is gradually opened. If, on the other hand, the accelerator is held depressed during the gear change so that the throttle is initially open, then on the application of suction to cylinder 8 the throttle is partially or wholly closed and the contacts 59, 60 are closed, so that, on release of the lever 1, the clutch immediately begins its engaging movement and the throttle gradually re-opens. The magnet 4 may also be energised by a brake-operated switch 67 provided a manually-operable switch 68 in series therewith is closed. In the second arrangement shown in Fig. 7, the locking pin 47 and cylinder 8 are dispensed with, the accelerator 16 is linked directly to the throttle 11, and a switch 84, which is normally open and is closed only by the clutch-engaging movement of the piston rod 19b of the servo 19 by means of a spring-loaded rocker arm 86 carried by the rod 19b, controls an electromagnet 75a adapted to lift a rod 71. In this form, the accelerator is manually released during a gear change, but, when the clutch automatically re-engages on release of the lever 1, the magnet 75a is energised and the rod 71 raised to lift the throttle link 15a so as automatically to open the throttle temporarily. A further switch 69 in series with switches 67, 68, is normally closed by a spring- loaded diaphragm but opens, when the suction in the manifold 1a reaches a pre-determined amount, so that the switch 67 is rendered ineffective above a certain engine speed.