Security bars.

摘要

A security bar for use in grilles or gratings, for example to protect the window openings in secure buildings against intrusion or escape. The bar has a central steel core 5 to provide bending resistance, sheathed in a layer 7 of material having enhanced resistance to sawing and filing. The layer 7 preferably comprises nuggets 8 of alumina, silicon carbide or the like very hard material bound in a matrix 9 of polymer or cement, cast into the sapce between the core 5 and an outer finishing skin 6.