Projection welding of an aluminum sheet

A projection welding apparatus for creating projection welds between a metal sheet overlying an adjacent metal body, said sheet having a projection extending toward the body, comprising:

• a stationary housing;
• a rod partially mounted in said housing and including a bore therein;
• an actuating device moving said rod relative to said housing from a start position to a contact position and an end position beyond said contact position;
• an electrode assembly mounted to a free end of said rod, said electrode assembly including a hollow, lightweight tube received in said bore and extending axially from said rod and an electrode adapted to contact one of the sheet and metal body when said rod is in said contact and end positions;
• a spring unit engaging said rod and tube so as to bias said tube axially outwardly of said rod;
• and
• an elongate, laminated electrical conductor supported in a generally U-shaped configuration and including a first leg fixed to said housing and a second leg fixed to said electrode assembly, said conductor being adapted to receive an electrical welding current at said first end and transmit said current to said electrode assembly and the projection on the sheet, said second leg extending transverse the axis and axial travel direction of said tube.