Door or window closure monitoring device for public utility unmanned operation areas

摘要

The monitoring device uses a coil (32) which detects the position of the door or window closure catch (14) relative to the reception recess (22) for the catch provided by the door or window frame. The coil fits around the periphery of the reception recess, in a plane perpendicular to the catch movement, so that an AC filed is induced in the coil when the catch is moved into and out of the closed position.