Patent ID: 8872060

Claim:
An apparatus for forming a sheet into a continuous beam having four exterior walls and a common center leg extending between an opposing two of the walls, the four exterior walls defining a rectangular cross-section, and the common center leg dividing the rectangular cross-section into first and second adjacent tubes, the common center leg having radiused ends each defining slip planes perpendicular to the common center leg, and the sheet having edges that abut the radiused ends, comprising: a roll former including roll form stations with rollers for forming the sheet into the continuous beam with the four exterior walls and the common center leg, the roll former including a welding station with welders and a weld box fixture, the weld box fixture including a fixture frame, external mandrels supported by the fixture frame and supporting the four exterior walls in a desired accurate shape, two of the external mandrels being movable and opposing, and including at least one actuator operably connected to at least one of the two opposing external mandrels for biasing the one opposing external mandrels into engagement with associated opposing ones of the four exterior walls; and internal mandrels in each of the first and second adjacent tubes that are supported by upstream anchor lines so that the internal mandrels remain generally adjacent the external mandrels; whereby, the internal and external mandrels, in combination with a bias of the at least one actuator, control a shape of the continuous beam by flexure and movement of material of the sheet when in the weld box fixture during a welding process of the welder; and wherein the welder includes a top welder and a bottom laser welder to weld the continuous beam respectively at a top location and a bottom location on the continuous beam, the bottom laser welder generating a laser beam angled from a vertical axis and pointed to weld a bottom radiused end of the common center leg to an edge of the sheet.