| 摘要 |
<p>1328966 Mechanical switches; retractive switches JOSEPH LUCAS (INDUSTRIES) Ltd 8 Jan 1971 [17 Jan 1970] 2368/70 Heading H1N A key operated ignition switch comprises a base 12 containing fixed contacts 29, 31, 32, 33, 34, and a rotor 13 carrying movable contact arms 15, 16 and a movable contact member 17 all co-operating with the fixed contacts to charge the circuit, arms 15, 16 also being brought into and out of engagement with member 17, by a cam surface 28 on base 12, the main operating gaps of the switch at which current is broken being between arms 15, 16 and member 17. Each arm 15, 16 has a silver contact 18 cooperating with contacts 18a on -member 17. Arms 15, 16 are urged by springs 19, Fig. 2 (not shown), into contact with member 17 and the fixed contacts and are lifted off member 17 when required by their ends 26, 27 engaging cam track 28, arms 15, 16 pivoting on the fixed contacts. Member 17 is urged into contact with the fixed contacts by springs 36, 25. Arms 15, 16 have contact faces 22, 23 to engage fixed contacts 31, 32, 33, and member 17 has contact faces 35, 24 to engage the centre fixed contact 34 and the outer fixed contact 29. The circuit is thus from centre fixed contact 34 to the fixed contact 29, when selected, via member 17, this circuit being broken by member 17, and from centre contact 34 to the selected ones of fixed contacts 31, 32, 33 via member 17, contacts 18a and 18, and arms 15, 16, these circuits being charged at the fixed contacts by rotating rotor 13 but the current being broken at contacts 18, 18a by the tilting of arms 15, 16 by the cam track 28 as rotor 13 is rotated. The switch positions are as follows: first position (Fig. 4a), steering column locked and no circuit through the switch; second position (Fig. 4b, not shown), steering column unlocked, contacts 22 and 31 made to energize accessories circuit; third position (Fig. 4c, not shown), contacts 22, 31 still made, contacts 24, 29 made to energize ignition circuit; fourth position (Fig. 4d, not shown), contacts 22, 32 made but contacts 18, 18a on arm 15 broken so no circuit to contact 32, contacts 24, 29 still made, contacts 23, 33 made to energize starter motor solenoid to move pinion towards toothed wheel to engage starter motor drive although the starter motor is not operated at full power to start the engine; fifth position (Fig. 4e, not shown), contacts 24, 29 still made, contacts 23, 33 still made, contacts 22, 32 still made but as the switch is rotated to the fifth position cam follower 26 enters a depression or cam track 28 so that contact 18 on arm 15 engages its associated contact 18a and circuit to contact 32 is completed and starter motor is operated at full power. Detent means (not described) keep rotor 13 in all positions except fourth and fifth from which rotor 13 retracts to its third position, from which it cannot be returned to its fourth or fifth position without first being returned to its second position.</p> |
