Patent ID: 7832168

Claim:
A roll-formed grid member for a suspended ceiling made from a single metal strip, the member being generally symmetrical about an imaginary central vertical plane and having a cross-section that includes a lower horizontal flange extending laterally on both sides of the central plane, the flange being formed of a double layer of said metal strip folded back on itself at each of its lateral extremities, a lower layer of said double layer flange being continuous between said lateral extremities and in contact with an upper layer of said double layer flange, a generally vertical stem formed of two layers of said metal strip, one stem forming layer on each side of said imaginary plane, said stem forming layers abutting and being fixed together at locations along the length of the grid member including its mid-length to prevent relative longitudinal sliding movement therebetween and thereby increasing the torsional stiffness of the grid member from what would occur where said layers are free to slide relative to one another; and wherein said generally vertical stem forming layers are in abutting a contact zone and forming layers are separated to form reinforcing bulb in a zone below said contact zone.