(57) @ A device for burglary alarm protected doors intended to prevent unintentional unlocking
of the lock mechanism of a door when the alarm circuit is operative, including aslide
(3), displacably arranged at the outside door plane, arranged to be locked by means
of an electromagnet (7) in a position extending across the key hole of the lock mechanism
when the alarm circuit is operative. According to the invention, the slide (3) is
arranged to influence an electrical swith means (8) when in a position extending across
the key hole, thereby interrupting a voltage feed from the alarm circuit to the electromagnet
(7). An initial displacement movement of the slide (3) in direction away from the
key hole results in that the switch means (8) closes the voltage feed circuit to the
electromagnet (7) from the alarm circuit, whereby the electromagnet (7) locks the
slide (3) after an initial displacement movement against further movement away from
the key hole. As soon as the slide (3) is no longer manually influenced, the slide
(3) after an initial displacement movement against further movement away from the
key hole. As soon as the slide (3) is no longer manually influenced, the slide (3)
returns to the position influencing the switch means (8), and the voltage supply to
the electromagnet (7) is interrupted.
|
|
