Workpiece feeding apparatus in seam welding machine

The combination of a workpiece feeding apparatus and a welding machine comprising:

• a seam welding machine having a machine body and a pair of electrode rolls provided on the machine body to engage a workpiece for welding a seam thereon;
• a workpiece feeding apparatus comprising a robot mechanism supporting a chucking means for holding a workpiece, said robot mechanism being arranged to move said workpiece three dimensionally in rotation and translation in any desired direction to assume any posture;
• said workpiece feeding apparatus being arranged with respect to said welding machine to hold a workpiece in position for engagement by said electrode rolls along a three-dimensionally curved portion of said workpiece to be welded, and for controlling movements and posture of said workpiece to maintain said workpiece in engagement with said electrode rolls along said portion to be welded;
• and
• said robot mechanism of said workpiece feeding apparatus comprising a robot main body mounted on said welding machine body, said robot main body and said electrode rolls being arranged to be relatively turnable with respect to each other about at least one of a pair of parallel axes, at least one of which axes is an axial line passing through the centers of said electrode rolls.