Fireproof building column assemblies

Claim 1

IN A RECTANGULAR FIREPROOF BUILDING COLUMN ASSEMBLY, A COMPOSITE EIGHT-PIECE, FLOOR-TO-CEILING OUTER COLUMN SHELL ADAPTED TO ENCLOSE A MASS OF FIREPROOFING MATERIAL AND COMPRISING FOUR IDENTICAL CORNER STRIPS AND FOUR INTERVENING WALL PLATES, SAID CORNER STRIPS AND WALL PLATES BEING FORMED OF SHEET METAL OF UNIFORM THICKNESS, EACH CORNER STRIP BEING IN THE FORM OF A VERTICALLY EXTENDING ANGLE PIECE OF RIGHT ANGLE CONFIGURATION AND PRESENTING DIVERGING SIDE WINGS, EACH WALL PLATE BEING OF FLAT RECTANGULAR CONFIGURATION, EACH CORNER STRIP HAVING A SIDE WING COPLANAR WITH A SIDE WING OF AN ADJACENT CORNER STRIP, EACH WALL PLATE BEING INTERPOSED IN COPLANAR RELATIONSHIP BETWEEN THE COPLANAR SIDE WINGS OF THE ADJACENT CORNER STRIPS, THE ADJACENT VERTICAL EDGES OF THE SIDE WINGS AND WALL PLATES BEING FORMED WITH INTEGRALLY SLIDABLY AND CLOSELY INTERLOCKED INWARDLY AND LATERALLY OFFSET FIRST AND SECOND HOOK PORTIONS RESPECTIVELY BY MEANS OF WHICH SUCH SIDE WINGS AND WALL PLATES ARE MAINTAINED IN CONTIGUITY, THE FIRST HOOK PORTION ON EACH VERTICAL EDGE OF EACH WALL PLATE CONSISTING OF A LATERAL SECTION AND A REENTRANT SECTION SPACED FROM THE PLANE OF THE WALL PLATE A DISTANCE EQUAL TO THE THICKNESS OF THE SHEET METAL, THE COOPERATING SECOND HOOK PORTIONS ON EACH VERTICAL SIDE EDGE OF EACH CORNER STRIP CONSISTING OF A FIRST LATERAL SECTION, AN INWARDLY OFFSET SECTION, A SECOND LATERAL SECTION, AND A RE-ENTRANT SECTION SPACED FROM THE INWARDLY OFFSET SECTION A DISTANCE SUBSTANTIALLY EQUAL TO THE THICKNESS OF THE SHEET METAL, SAID SECOND HOOK PORTION THUS DEFINING AN L-SHAPED SLOT WHICH SLIDINGLY RECEIVES THE FIRST HOOK PORTION WITH THE INWARDLY OFFSET SECTION AND THE REENTRANT HOOK PORTION THEREOF EMBRACING THE OPPOSITE SIDES OF THE RE-ENTRANT PORTION OF THE FIRST HOOK PORTION IN SUBSTANTIALLY CONTIGUOUS FACE-TO-FACE RELATIONSHIP, THE TRANSVERSE DIMENSION OF EACH PAIR OF INTERLOCKING HOOK PORTIONS BEING EQUAL TO FOUR THICKNESS OF SHEET METAL.