| 摘要 |
An electric contact is arranged to trigger an alarm signal in connection with an attempt to break open a lock 4, which contact is arranged in a contact housing 1 such that it is controlled by a small plate 2, which plate 2 normally prevents entry to the lock 4 but which, as it is swung out when the lock is exposed, closes an electric current circuit to an alarm mechanism equipped with a delay. <IMAGE> |
