Apparatus for making a tri-metallic composite electrical contact

Abstract

A tri-metallic electrical contact consisting of a head wire piece and a base wire piece which abut to an intermediate piece at its opposite ends, is produced by cold press operations performed by first and second die and punch sets. The first die and punch set causes plastic deformation of approximately only a half part of the aligned wire pieces, while keeping another half part of these pieces not deformed. The second die and punch set imparts, subsequent to, and independently from, the cold press operation performed by the first die and punch set, plastic deformation to the other half part of the pieces, whereby the abutting surfaces of the three wires are prevented from sliding movements laterally relative to each other during the cold press operations, and whereby irregular or insufficient deformation of the wires due to the differences of yield points of the wires is prevented.