| 摘要 |
A device to be mounted on a fence, or other structure, and adapted to switch a circuit, such as an alarm circuit, in response to excessive motion of the fence and/or in response to tampering with the device in an effort to inactivate it. The device includes a housing having a removable closure and containing a single, normally closed switch connected in an alarm system, means responsive to removal of the closure for opening the switch to actuate the alarm system, and means responsive to excessive motion of the housing for opening the switch to activate the alarm system.
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