For installing into GIB ceiling without attaching to ceiling joists.
The aluminium hatch frame can be manufactured with cams on the outside of the frame. The screws holding these cams can be loosened or removed. Then the hatch can then be fitted against a trim hole in a gib ceiling, and the cams adjusted to fit against the GIB, and the screws tightened thus clamping the frame in place.
This precludes the need for installing framing as a support for the ceiling frame, and can speed installation considerably. This solution is only recommended when light-weight lid material is to be placed in the ceiling frame.
Specify this simple square or rectangular frame when needing to trim a ceiling opening.
This solution has proved most useful when needing to install a video screen which withdraws into the
ceiling cavity. It then can be descended when needed.