| 摘要 |
A solenoid plunger 14 of the switch 4 is moved by cam plunger 34 and is biased towards the cam plunger 34. A locking plate 40b is positioned between the plungers 14 and 34. Cam plunger 34 is biased towards a cam 22 and is moved towards the solenoid plunger by rotation of the cam 22 by insertion of actuator 8 which causes retraction of the solenoid plunger into the switch 4. The locking plate 40b is lockable when the cam plunger 34 is biased into a detent 36 in the cam 22 when the actuator is inserted, to lock the cam plunger 34 and cam 22 and prevent removal of the actuator 8. Locking means 48 can slide on a running track (fig 2, 38a,b) to move into the path of locking arm 40b preventing it from pivoting (fig 3) towards the solenoid plunger. The lock 48 can be held in the lock position by a profiled surface 14a on the solenoid plunger when it is biased out of its housing. Two contact blocks (fig 2, A,B) can have normally open and closed contacts and be operated independently by the solenoid plunger and by the actuator, indicating whether the solenoid is energised and whether the actuator is inserted. The switch can be used on the guard door of a machine to cut power when the guard is open and resists tampering by insertion of a foreign object into the switch.
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