Security grille for opening in building

摘要

The grille comprises parallel bars and cross-struts (5,6) of oval cross-section. The cross-struts pass through openings in the bars and contain filler material (8). They can be in two or more rows with those in adjacent rows offset from each other. A layer of woven steel (19) can be included, typically at the indoor side, and with a grating (20,21) at each side of it. Metal bars (9,10) can be contained inside the struts.