GB1362176A - Ignition switches - Google Patents

Abstract

1362176 Inert switches; cam-operated switches; retractive switches JOSEPH LUCAS (INDUSTRIES) Ltd 11 Nov 1971 [21 Nov 1970] 55499/70 Heading H1N An ignition switch comprises a rotor 13 rotatable from a stable first position (accessories) to a stable second position (ignition) and an unstable third position (start) from which it is resiliently urged back (by spring 26) to the second position, and a first bridging member 19 rotatable with rotor 13 and completing a circuit between a fixed contact 21 (battery) and a fixed contact 24 (starter motor) in the third position, member 19 being resiliently urged (by spring 35) against an arcuate cam track 27. Cam track 27 is such that if rotor 13 is moved from the second position to the third position unless the preceding movement was from the first to the second position, bridging member 19 is moved by cam track 27 in such a direction that in the third position the circuit between contacts 21 and 24 is not completed. As shown, a second bridging member 16 bridges contact 21 and contact 22 (accessories), Fig. 2 (not shown), in the first position and contact 23 (ignition) in the second and third positions, the circuit between contacts 21 and 24 in the third position being through members 16 and 19 which are in engagement when rotor 13 is moved from the first to the second and third positions but not in engagement when rotor 13 is moved from the second to the third position without the preceding movement having been from the first to the second position. The cam track 27 is shown in Fig. 3. In the first position the end of member 19 is adjacent wall 12a, when moved to the second position it moves to wall 32a and when moved to the third position it moves to wall 32b. When moved by spring 26 back to the second position it moves up ramp 33 on to surface 29a, and member 19 is pivoted by the track away from member 16. If then the rotor is moved to the third position the end of member 19 runs along surface 31 to surface 29b so that member 19 is maintained away from member 16. If, from the second position the rotor is moved to the first position, the end of member 19 runs from surface 29a over the edge of wall 32 back to its original position so that member 19 re-engages member 16 and the cycle can be commenced again. A stable "off" position is also provided (not shown). In the second embodiment, Figs. 4, 5 (not shown) the cam track tilts the first bridging member 48 away from the starter motor contact 54 when its end runs up ramp 33 instead of breaking contact between the first and second bridging members, also a spring-loaded ball and recess detent arrangement is provided for the stable rotor positions. In both embodiments, the rotor is turned by a lock (not shown) operated by an ignition key. Both embodiments are provided with a locking position for preventing movement of the gear selector shaft, Fig. 4 (not shown), by a ball 45, engaging a recess 46 in gear selector shaft 44.