Miniature plug-in fuse assembly and method of making a fuse element therefor

A method of making one-piece composite fuse elements each having two generally parallel tubular terminal prong portions with respective longitudinal axes laterally spaced a predetermined distance apart and a fuse link portion of substantially smaller cross sectional area than said terminal prong portions extending transversely between said terminal prong portions characterized by the steps of:

• providing an elongated flat sheet of fuse metal that is potentially divisible into successive incremental lengths from each of which a fuse element blank and a connecting strip is available;
• advancing said sheet longitudinally in successive steps along a fixed path of travel lying in a predetermined plane;
• subjecting each incremental length of said sheet to at least one punching operation to thereby form a flat connecting strip and a flat fuse element blank, each of said fuse element blanks including two laterally spaced and longitudinally extending prong members interconnected at their inner lateral edges by a link member of substantially smaller cross sectional area than said prong members and having a non-rectilinear configuration, each of said prong members being connected at one end of said connecting strip and at its other end to a successive connecting strip by a respective narrow tongue member of a width which is substantially less than the width of each said prong member, the tongue members at the opposite ends of each prong member being disposed along a respective longitudinal line substantially closer to the inner lateral edge of each said prong member than to the outer lateral edge thereof;
• said longitudinal lines extending generally parallel to said fixed path of travel and being spaced from each other a distance substantially equal to said predetermined distance of lateral spacing between the longitudinal axes of said terminal prong portions;
• thereafter while maintaining said tongue members in the plane of said sheet along respective ones of said longitudinal lines subjecting each fuse element blank to at least one shaping operation to thereby displace the respective inner and outer lateral edges of the prong members thereof out of the plane of said sheet in the same one direction and shape each said prong member into tubular form to define said terminal prong portions, the link member of each said fuse element blank being displaced out of the plane of said sheet in said one direction and being flexed from said non-rectilinear configuration to thereby elongate said link member to define said fuse link portion while said prong members are being displaced and shaped;
• and thereafter severing each formed and shaped fuse element from the connecting strips.