| 摘要 |
The lock housing (1) fits into a door panel, and the lock bolt (3) is movable by a key between the drawn-in and projecting -locked - positions. On its surface facing the closure plate, the bolt has two contacts (5,7). The contacts are electrically insulated from the bolt and from one another, and are connected to electrical leads (9,11). They are spring-loaded so that they normally project outside the bolt front surface, and against spring effect can be pressed into the bolt. On the side of the bolt is a projection (13) which in the bolt drawn-in position activates a lever (15) in a micro-switch (17) connected by leads (19,21) to an electrical alarm circuit. The contact electrical leads are also connected to this circuit. Incorporated in the circuit is a piezo-electric buzzer (25), and in the edge of the door facing the lock housing are a number of holes (27) which permit adequate audibility of sound from the buzzer. A radio transmitter can also be connected to the buzzer for transmission of an alarm signal to a surveillance station or to a telephone receiver. |
