ALARM CONDITION SENSOR

专利名称：ALARM CONDITION SENSOR发明人：WETZ L,US申请号：US3763795D申请日：19720628公开号：US3763795A公开日：19731009

摘要：An alarm condition sensor for enclosing a device to be protected, such as avault, which will change its electrical properties and thereby facilitate an alarm indicationwhen a person tampers with the sensor and/or attempts to cut, burn or otherwisepenetrate the protected device to gain access thereto. The alarm condition sensorincludes frangible, opaque panels adhesively secured to the exterior surface of theprotected device to completely enclose it. The panels have a printed circuit on the insidesurface thereof which is electrically insulated from the exterior of the protected device,and due to the opaqueness of the panel is not visible from the outside. Attempts to pry,fold, bend, or otherwise remove the frangible panel prior to penetration of theprotected unit itself will cause the panel, by virtue of its brittleness, to break,interrupting the electrical continuity of the printed circuit formed thereon. Similarly,attempts to drill, cut, or otherwise penetrate the protective panel, which necessarilyoccur prior to penetration of the protected unit, either interrupt the electrical continuityof the printed circuit or at least short-circuit it to ground via the vault which is typically ofconductive material. In either case, a change in the electrical circuit occurs which can besensed and an alarm indication provided prior to the point in time when the protectivedevice is actually penetrated.

申请人：MOSLER SAFE CO,US

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