| 摘要 |
A partially conductive security screen arrangement for use with an intrusion alarm system designed to operate in a normally closed sensing circuit condition and to produce a warning signal when the sensing circuit is broken, which arrangement includes conductive means overlying and bonded to a mesh screen positionable to cover an opening in a building. The conductive means is connectible at its two ends to the sensing circuit in a series relationship with the remainder of that circuit. The conductive means is positioned on the screen in a configuration preventing passage of a human being through the screen unless the conductive means is severed. Passage of a human being through the opening while the screen is in position to cover the opening therefore breaks the sensing circuit to produce a warning signal. One or more electrical switches located within a frame at the periphery of the screen may also be connected in a series relationship with the remainder of the sensing circuit, the switches being adapted to close for the screen in position covering the opening in the building and to open for the screen moved out of that position. The conductive means may include a plurality of parallel longitudinal lengths of wire connected in series with each other and with one or more transverse lengths of wire. The respective lengths of wire may be mechanically interlocked with each other and with the mesh screen at the points of intersection therebetween.
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