PROTECTED ENTRANCE Russian patent published in 1998 - IPC

FIELD: protected entrance for protection of entrances to structures to town underground space. SUBSTANCE: a hinged panel is installed in the upper part of the covering of the entrance inclined section. The panel is hinge- mounted by its lower side in the covering of the entrance inclined section and rests with its upper side on spring retainers entering the holes of the upper supporting fixing members. The latters are fastened on the reinforced-concrete beam of the covering. The spring retainers are kinematically linked with electromagnetic locks. A tie-rod is installed above the upper surface of the hinged panel. The tie-rod is fastened to a curvilinear connecting element linked with the spring of the spring-anchor device. A rarefaction wave contactor is installed on the external surface of the hinged panel, and a protective housing is attached. The upper supporting assembly of the hinged panel is covered by a protective apron. The spring-anchor device is made of a cylindrical metal sleeve. The latter is installed in the hole of the reinforced-concrete stop and fastened to the covering of the entrance inclined section by means of supporting clamps. EFFECT: enhanced reliability of protection of entrance inclined section with a stepped slope, entrance horizontal section, reduced specific consumption of materials and own weight of protective devices of entrance door apertures. 4 cl, 5 dwg