US Patent 7648213 Mechanism for fastening casing into wall opening

A fastening mechanism for fastening a casing (2) into an opening in a wall (4), the mechanism comprising a collar element (6) fastened to the casing and arranged to be in contact with a first side of the wall, a pressing element (8) arranged to be in contact with a second side of the wall, the collar element and the pressing element being arranged to co-operate to direct a pressing force towards the w all, and a screw means (10) arranged to move the pressing element. The pressing element is arranged to rotate between a normal position and a mounting position; in the normal position the pressing element is capable of coming into contact with the second side of the wall to achieve a force keeping the casing (2) in place and in the mounting position it allows the casing to be pushed into the final mounting depth.