PROTECTIVE SHELL Russian patent published in 2001 - IPC

FIELD: construction of underground structures; applicable in conduction of emergency and rescue operations in ruins of buildings and structures, passages in grounds and also in capacity of small-size protective structure. SUBSTANCE: protective shell is made of metal screen or of roll sheets secured to external surface of rings formed by segments in interconnected by two-sided bolted planks and connected along shell length by interring couplings. Shell has end conical caps and flexible connecting lock bar. Ring segments are rectangular in plan and made, at least, of three tubular bows of different length and interconnected by ends with angular members which are secured together in their top. Bows are located in a space relation to each other and fastened by ends with angular members by means of welded or screwed joints and cylindrical inserts. The latter are secured in cavities on bow ends with screws. Metal screens or roll sheets are made according to sizes of segment surfaces and secured to angular members by means of bolted joints. Angular members of neighboring segments along their length may be connected with some gaps by two bolts with cylindrical heads and nuts with vertical thread on side surfaces. Interring couplings and couplings between rings and caps are made of straight and bent connecting plates, respectively, installed in gaps of side and lower joints of segments. Installed in gap of upper joint may be flexible connecting bar of lock formed by pan-like insert filled with flexible material, for instance, with polyurethane foam. In this case, all connecting pins are secured by their ends to neighboring rings or rings and caps by bolts. EFFECT: protected end face parts, reduced weight and overall dimensions, no need of mounting devices and tools, reduced time and labor and material inputs in shell construction. 2 cl, 11 dwg