Device for protecting objects against unauthorised taking away

摘要

In order to protect objects against unauthorised taking away, a radiation field is produced in the region being monitored. Locking devices are fitted to objects to be protected, which locking devices have a sensor (12), which reacts to the radiation field, and a signal transmitter (13). When the locking device is closed, the output signal from the sensor (12) is supplied via a locking contact (21) to the signal transmitter (13) which is in consequence prevented from producing an alarm signal. If the connection between the sensor (12) and the signal transmitter (13) is broken (interrupted), then the signal transmitter (13) is changed into the alarm mode. An alarm is produced whenever the locking device leaves the radiation field produced in the monitored region or if the locking device is detached in an unauthorised manner. <IMAGE>