Plate for arranging with its docking side on projectors for its suspended connection on roof, has elongated spiral hole that extends from docking side of plate to other side

摘要

The plate (5) has a spiral elongated hole (11) that extends from the docking side of the plate to the other side. The elongated hole has interceptive transverse webs (12) for increasing the rigidity of the plate. The elongated hole runs from the center of the plate without increasing the radius.