Ceiling suspension system

Claim 1

A CEILING SUSPENSION SYSTEM IN THE FORM OF A RECTANGULAR GRID COMPRISING INTERCONNECTED MAIN SUSPENSION MEMBERS, AND CROSSSUSPENSION MEMBERS, MEANS FOR SUSPENDING SAID MAIN SUSPENSION MEMBERS IN SPACED, PLANAR, PARALLEL RELATIONSHIP, EACH OF SAID SUSPENSION MEMBERS COMPRISING A UNITARY SHEET OF MATERIAL LONGITUDINALLY FOLDED TO FORM IN CROSS-SECTION A GENERALLY INVERTED V, HAVING A REINFORCING BEAD AT THE APEX OF THE V, OUTWARDLY EXTENDING FLANGES AT THE BASE OF SAID V AND PLANAR SIDEWALLS INTEGRALLY CONNECTED TO SAID REINFORCING BEAD ALONG ONE EDGE OF EACH OF SAID SIDEWALLS AND TO SAID FLANGES ALONG THE OPPOSITE EDGE OF SAID SIDEWALLS AND DIVERGING IN THE DIRECTION TOWARD SAID FLANGES; SAID SIDEWALLS OF SAID MAIN SUSPENSION MEMBERS HAVING SLOTS THEREIN, SAID SLOTS HAVING AN OPENING WITH A WIDTH OF ABOUT TWICE THE THICKNESS OF SAID SHEET AND A LOCKING TAB STRAPPING THE UPPER END OF SAID OPENING, AND SAID CROSS-SUSPENSION MEMBERS HAVING END CONFIGURATIONS FORMED BY CUTTING PORTIONS OF CERTAIN OF SAID MAIN SUSPENSION MEMBERS, SAID END CONFIGURATIONS BEING SUCH AS TO LOCK SAID MAIN AN CROSS-SUSPENSION SYSTEMS IN A RIGID GRID.