Panel welding system

A welding apparatus for automatically or semi-automatically fillet welding an elongate stiffener to a flat workpiece, comprising in combination:

• a workpiece supporting bed including vacuum means for releasably holding down a workpiece flat against the bed;
• carriage supporting means overlying said bed;
• traveling carriage means cooperating with said carriage support means for controlled travel in a plane overlying said bed;
• a welding torch and stiffener positioning head assembly mounted on said carriage means for traveling therewith relative to said bed and a workpiece held down thereon, said head assembly comprising:
• a first welding torch means mounted on said head support structure and disposed for forming a fillet weld along a seam at which one lengthwise edge of a stiffener contacts an upper surface of a flat workpiece:
• a plurality of coacting down pressure and lateral steering roller assemblies supported by said head support structure;
• said down pressure roller assemblies comprising a leading down pressure roller assembly and a trailing down pressure roller assembly, truck means for mounting said leading and trailing down pressure roller assemblies with respect to said head support structure for rolling contact with an upper lengthwise surface portion of a stiffener at locations spaced apart along a direction of head travel and so that said leading down pressure roller assembly contacts a stiffener at a predetermined distance in advance of said first welding torch means and so that said trailing down pressure roller assembly contacts such stiffener at a location adjacent said first welding torch means;
• said lateral steering roller assemblies comprising at least first and second steering roller assemblies mounted on said head support structure so as to act inwardly against opposite sides of a stiffener for rolling contact with side portions thereof at a location along the direction of head travel that is intermediate said leading and trailing down pressure roller assemblies so as to laterally steer a stiffener to a predetermined line of attachment prior to formation of a fillet weld by said first welding torch means.

A method of automatically or semi-automatically welding an elongate stiffener to a substantially flat workpiece, comprising the steps of:

• holding such workpiece down against a supporting bed by developing a suction force on the underside of the workpiece;
• controllably guiding a welding torch, down pressure and steering roller supporting head assembly along a predetermined stiffener attachment line on an upwardly facing surface of the workpiece so as to form a fillet weld along a lengthwise edge portion of a stiffener that is in contact with said workpiece surface;
• exerting an initial down pressure on the stiffener in advance of the forming of said fillet weld by a leading down pressure roller mounted on said head assembly;
• laterally steering the stiffener, also in advance of the forming of said fillet weld by exerting inwardly opposing side pressure on the stiffener with laterally movable steering rollers disposed downstream of the leading down pressure roller;
• and,
• exerting a final down pressure on the stiffener at a location adjacent to the point of formation of the fillet weld by a trailing down pressure roller mounted on said head assembly.