Method for security fitting of window grid with inner and outer steel plates linked by a steel tube and with a securing bolt set through the tube and with no tool grip on its outer head

摘要

A method for security fitting of a window grid (1) has a threaded sleeve (4) welded to a steel plate secured to the outside of the wall. A steel tube (3) is welded to a steel plate (13) on the inside wall and set through the wall and secured to the outer sleeve via a threaded end. A securing bolt (2) is set through the outer sleeve and is secured by a nut (7) on the inside wall. The head of the bolt is smooth and provides no grip for any tool. The inside fixing of the bolt is secured by a square section metal duct (8) welded to the inner metal plate and with a key operated outer closure. This prevents release of the security grid even with the window smashed.