| 摘要 |
A plunger-operated alarm switch assembly (10) provides without visual inspection thereof an indication of whether a barrier (14) is in a secure position or whether the alarm switch assembly has been tampered with. A preferred embodiment includes a plunger housing (18) that is matable to a switch plate (20). The plunger housing supports a movable plunger (22) having a permanent magnet (24) that produces a magnetic field (26). The switch plate supports a magnetically actuatable reed switch (28) positioned in a predetermined relative alignment to a guide path (32) of the plunger when the plunger housing and the switch plate are matably fitted together. The plunger is movable relative to the plunger housing between alarm and secure positions so that whenever the plunger is in the alarm position, the reed switch provides an alarm switching condition; whenever the plunger is in the secure position, the reed switch provides a secure switching position; and whenever the predetermined relative alignment of the reed switch and the guide path of the plunger changes, the reed switch provides the alarm switching condition.
|
