Inspection hatch unit - covers wall aperture and comprises frame to which is fixed front plate

摘要

The front plate (4) projects in all directions outside the frame (3) against the wall front side. The frame has plates (5) in its rear side to retain fireproof insulating material (7). Between the frame plates and the front plate are sockets (8) for guiding headed (12) bolts (11) extending through an aperture (10) in the plate. The end of the bolt extending out of the aperture is bent so that in its turned position it can locate against the wall rear side. A spring (16) strives to press the extending part of the bolt against the wall rear side.