GB354010A - Improvements in or relating to ignition control apparatus - Google Patents

Abstract

354,010. Latching ignition switches for internal-combustion engines. BOSCH AKT.-GES., R., 4, Militõrstrasse, Stuttgart, Germany. June 21, 1930, No. 18959. Convention date, June 29, 1929. [Class 38 (v).] In double-ignition systems in which two sources of ignition may be switched on alternatively or simultaneously by a rotary ignition selecting switch which may also be axially displaceable to cut out both systems, a timing switch is combined and preferably interlocked with the combined cut-out and ignition selecting switch in such a manner that when the ignition is cut off the timing switch is automatically placed in the position corresponding to retarded ignition. As shown in Figs. 1 and 2, the switches are mounted in a cover 1, the upper switch constituting a combined cut-out and selecting switch and the lower switch controlling the timing. The upper switch has a rotatable and axially-movable insulating cylinder 6 on the periphery of which are metal segments 7 on which relatively fixed contact springs 10 are adapted to bear. Grooves 9 are formed in the periphery of the switch member at positions corresponding to the inner or " cut-off " position and the outer or working position the switch member being moved axially by a pushbutton 2 at the end of a rod 4 on which the switch drum is secured. This switch nay be moved to differemt angular positions corresponding to one, other, or both of the magnetos, by a rotatable handle 14 secured to a sleeve 12 which carries a pin 13 passing through a slot 11 in the rod 4. A cam plate 18 is provided on the movable switch member so as to partake in its longitudinal movements but is held against rotation by a pin 15 secured to the cover 7. The pin 15 also secures a plate 16 behind the cover, this plate having a lateral extension 26 at its bottom end to which is secured one end of a coiled retractive spring 25 surrounding the spindle 20 of the timing switch. This switch is operated by a handle 21 and carries an oval contact plate 22 adapted normally to co-operate with fixed contact springs 23 to switch in a separate retarded interrupter. The spring 25 is mounted within a casing 24 on the timing switch spindle and has its free end passing outwardly through a slot in this casing in the form of a projection 27. On operation of the switch to move into the " advanced " position the projection 27 moves past the raised part of the cam plate 18 which retains the timing switch in this position until the upper switch is depressed to cut out the ignition circuits. This movement similarly displaces the cam plate 18 so that the projection 27 escapes and the timing switch is automatically returned to its " retard " position in readiness for subsequent starting of the engine.