| 摘要 |
A strip of conductive spring material is formed in a loop with extending ends adapted to be clamped together by closed doors and windows. In one embodiment, a conductive rod member has a hook at one end, the other end of the rod member being fixedly connected to one side of the loop, the hooked end extending through a hole in the other side of the loop. An apertured contact member is mounted on and insulated from the outside of the other side of the loop. The loop is unclamped when the door or window is opened and a circuit is completed between the hooked end and the contact. In another embodiment, the loop is positioned between two stationary contacts, being permanently attached to the first one of the contacts. When the extended ends are clamped, the loop does not touch the second contact, but when the ends are unclamped, the loop bridges the two fixed contacts to complete an alarm circuit.
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