| 摘要 |
A window assembly controls ventilation and prevents passage through the window opening. Provides hardened steel horizontal bars spaced apart vertically a distance that prevents passage. The bars are welded to hardened steel frame members. The steel assembly is anchored in the wall by resistant anchoring elements. The bars may be secured in place by other means. Glazed aluminum vents have top rails that enclose the bars and pivot upon them. Aluminum frame members enclose the steel frame members and support operator means that rotate the vents on the bars to open and close the vents. The angle of opening may be limited to prevent the vent extending beyond the wall at walkways.
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