Abstract: A controlled expansion suspended ceiling grid beam for a suspended panel ceiling comprises a web having a panel supporting flange provided along one of its marginal edges and a bead integral with the other marginal edge. An expansion accommodating portion is provided in the beam for accommodating and localizing thermal expansion. It comprises an arrangement of cut outs in the web which defines three spaced apart notches extending down near to the flange to provide areas of bending for the flange on beam expansion. The bead portion above the cut outs is adapted to collapse on beam expansion. A control means comprising web elements connected to the web portions located between the notches is adapted to resist both separation of and upward movement of the web portions at the beginning of thermal expansion to thereby initiate downward movement of the web portions and hence downward folding of the flange portion away from the bead in accommodating thermal expansion in the beam.

Abstract: A controlled expansion suspended ceiling grid member for suspended panel or tile ceilings comprises a web having a panel supporting flange provided along one of its marginal edges and a bead integral with the other marginal edge. The bead side walls are unconnected at the bead's base. An expansion accommodating portion is provided for accommodating thermal expansion in the beam and comprises three evenly spaced apart notches cut in the web in a manner which adapts the flange to fold downwardly away from the bead during beam expansion. The bead's top wall has slot means cut therein to essentially free the bead's side walls from transverse connection to adapt the side walls to buckle laterally out of their respective planes as the flange is folded so that the bead remains substantially horizontal and distortion along the beam's length is minimized.