| 摘要 |
<p>The invention relates to an alarm apparatus, preferably in a window structure, and including at least one glass pane (1) or similar sheet-like element. The alarm apparatus comprises at least one transmitter (6) of impulses, e.g. ultrasound, mounted at a first place on a glass pane (1) so that it can be subjected to said impulses, and at least one receiver (7) of the impulses transmitted in the pane (1), and mounted at an other place on the pane for registering impulses received from it, an alarm connected to the receiver (7) being triggerable when the impulses received from the pane (1) change, e.g. when the pane (1) is broken.</p> |
