Seam welding apparatus

A seam welding apparatus, which comprises:

• at least one roller electrode, which is rotatable;
• an other electrode for making a pair in cooperation with said roller electrode;
• and
• a main body for supporting said roller electrode and the other electrode,
• two metallic sheets to be welded, which are placed one upon another, being held at edge portions thereof between said roller electrode and said other electrode, said roller electrode being rotated to make a relative movement along the edge portions of the metallic sheets, while pressing the metallic sheets by both of the electrodes and applying an electric current to them therethrough, thereby seam welding the two metallic sheets,
• wherein:
• said main body supports a plurality of sets of two metallic sheets to be welded so as to place the sets of two metallic sheets in a line at a predetermined interval;
• said other electrode is a stationary electrode, which has a flat electrode surface continuously extending by substantially the same length as a portion to be welded of said metallic sheet, a portion of said stationary electrode, which includes said electrode surface, having a smaller thickness than said interval between the sets of metallic sheets, said electrode surface coming into contact with the portion to be welded of one of the two metallic sheets to be welded;
• said roller electrode is a disc-shaped body, which is rotatable around a central axis inclining at a predetermined angle relative to a surface of the metallic sheet, said disc-shaped body having an outer peripheral portion, which serves as a conical electrode surface based on a conical generatrix relative to the central axis, and said conical electrode surface being capable of coming into contact with the portion to be welded of the other of the two metallic sheets, in a state in which a top side of said conical electrode surface is placed on a side of the edge of the metallic sheet.