Patent GB-433279-A (GB)
Title: Improvements in or relating to automatic gear selection means for gear changing
Filed: 1933-11-04
Abstract: 433,279. Controlling variable-speed gearing. HILDEBRAND, F., 2, Walmannstrasse, Lankwitz, Berlin. Nov. 4, 1933, No. 30717. Void [Abridged as open to inspection under Sect. 91 of the Acts, May 7, 1934]. [Class 80 (ii)] In an automatic control device for changespeed gearing for automobiles, the changing of the transmission ratio is made to depend simultaneously on the speed of the driven shaft and on the position of the member regulating the energy supply to the engine, such as the accelerator 1. These two variables may be integrated by the use of the potential of a separately excited or other suitable generator 6 the speed of which is proportional to that of the driven shaft and the excitation of which depends upon the position of the accelerator 1. Alternatively a mechanical device such as a centrifugal governor may be used. The position of the governor sleeve determines the gear engaged for instance by means of a sliding contact on a contact plate displaceable by the accelerator. When the accelerator 1 is in the fully depressed position, the whole of the resistance 4 is in series with the field winding 5 and the current produced by the generator is insufficient to cause either of the electromagnets 9, 10 to operate their respective switches 7, 8. The current from a battery 11 passes by way of a contact 26, a coil 22, a contact 25 and a coil 21 to the terminal 12 of the gear selector for the low gear. As the generator current rises due to the release of the accelerator or to the increase in the speed of the vehicle, the switch 7 is moved against its spring so that instead of passing to the contact 25, the battery current passes to a contact 23, a coil 19 and thence to the terminal 13 of the intermediate gear selector. Similarly a further increase in the generator current operates the switch 8 and the battery current passes to a contact 24, a coil 20 and thence to the top gear selector terminal 14. The actual gear changes may be brought about electrically or pneumatically. The small coils 19, 20, 21, 22 produce a snap action which eliminates any instability during the gear changes. Thus when the switch 7 is raised, the coil 21 is cut out and the coil 19 acts on the switch in addition to the magnet 9. Similarly the coil 20 assists the magnet 10 when the switch 8 is raised. The battery current also passes via one of the contacts 29, 27, 28 to one of the respective interruptor switches 16, 17, 18 and thence to a coil 15 which temporarily closes a throttle valve in the inlet pipe of the engine. This valve is opened on completion of the respective gear change by one of the strikers 42, 43, 44 which opens the respective interruptor switch. The circuit to the coil 15 may also be interrupted by the coupling 41. The automatic selection may be cut out and a hand selector 48 used, by operation of a switch 47. Lamps 32, 33, 34 indicate the gear which is engaged. The brake pedal 2 may be arranged to act on the resistance 4 in the same direction as the accelerator so that as the brake is applied the lower gears are brought in. The invention is applicable to continuously variable gearing. The neutral and reverse gears may be included in the throttle lever control, and both may be operable automatically. The neutral gear may engage when the engine speed falls to a predetermined minimum or when the accelerator is in its position of rest. The neutral and reverse gear may alternatively have hand selectors.