Fuse construction

An improved insulator assembly for a dual element line fuse, comprising;

• a cylindrical insulator having a first end and a second end;
• a circular barrier flange having concentric and offset apertures therethrough;
• a conductive cylindrical eyelet having a sleeve portion terminating in a closed end and an open end, said open end further including a conductive flange radially disposed thereon;
• said cylindrical insulator receiving said sleeve portion and having said conductive flange abutting said cylinder first end and said closed end protruding through said cylinder beyond said second end;
• said closed end further disposed through said concentric aperture;
• said closed end including an engagement means for maintaining said cylindrical insulator and said barrier flange on said sleeve portion;
• and
• a conductive coil circumferentially engaged about said cylindrical insulator, said coil further including a radial end disposed on said conductive flange and a tail end disposed through said offset aperture.

A dual element line fuse comprising:

• a housing having an insulative body with conductive ends, said insulative body forming a compartment between said conductive ends;
• an insulative divider having a first aperture therethrough dividing said compartment into first and second cavities;
• a conductor extending through said compartment between said conductive ends for providing an electrical connection between said conductive ends, said conductor including a first conductive strip disposed in said first cavity and a coil and second conductive strip disposed in said second cavity;
• a conductive connector disposed in said second cavity and extending through said first aperture to close said first aperture and attach said conductive connector to said insulative divider, said coil and second conductive strip having ends soldered together on said conductive connector, said solder having a predetermined melting point;
• said insulative divider insulating said conductive connector from the remainder of said coil;
• and
• the other end of said coil extending through a second aperture in said divider for connection to said first conductive strip.

A method of making a fuse, comprising the steps of:

• providing a eyelet having a sleeve with a closed end and an open end with a radial flange having a quadrant slot therein radially disposed thereon;
• providing a coil having a radial end and a longitudinal coil tail;
• threading said coil over the eyelet and rotating the eyelet and coil with respect to each other to cause the coil radial end to pass through the quadrant slot to retain the coil on the eyelet;
• inserting the sleeve closed end into a hollow cylindrical insulator and the sleeve closed end and coil tail through a circumferential radial flange;
• crimping the closed end over said radial insulator flange;
• attaching the spring loop of a strip and spring assembly to the radial flange with a low melting point fusing alloy;
• soldering one end of a short circuit strip to the coil tail;
• cutting a length of insulator tubing and cutting opposed spring retainer notches in one end;
• crimping the insulator tube to form a series of circumferential projections about its inner circumference;
• pulling the strip and spring assembly through said tube until the insulator flange engages the protrusions, and the spring is located adjacent the opposed spring retainer slots;
• placing a spring hanger in the opposed slots in the insulator tube;
• tensioning the spring into tensile engagement with the spring hanger;
• packing arc quenching filler around the short circuit strip;
• threading the short circuit strip through a conducting washer, and folding the end of the short circuit strip against the washer;
• placing the conductive washer over one end of the insulator tube;
• placing a solder slug in the end caps;
• locating one end cap over the conductive washer and the adjacent end of said tube;
• heating the end cap to reflow the solder creating a solder joint between the short circuit strip, the conductive washer and the end cap;
• threading the heater strip through an insulating spacer;
• locating the insulating spacer on the end of the tube adjacent the spring hanger;
• folding the heater strip against the outer surface of the insulative spacer;
• placing the remaining end cap over the insulating spacer and adjacent tube end and heating the end cap to reflow the solder to create a solder joint between the heater strip and second end cap;
• and
• staking the end caps into gripping engagement with said tubular body;