Method and apparatus for making an encapsulated plug-in blade fuse

The method of making a three-piece solderless plug-in fuse element comprising the steps of:

• providing a pair of blades, each blade having at one end a terminal portion for being connected into an electrical circuit and at the other end a fusible link support spring clip;
• arranging said blades in spaced-apart, generally parallel relationship;
• and
• aligning a fusible link substantially perpendicular to each blade and inserting in into the spring clip of each blade to provide a solderless electrically conductive path from one of said blades through the fusible link to the terminal portion of the other end of said blades.

The method of making an encapsulated three-piece solderless plug-in electrically conducting component comprising the steps of:

• providing an elongate conducting element and at least two blades, each said blade having at one end a terminal portion for being connected into an electrical circuit and at the other end a conducting element support spring clip;
• arranging said blades in spaced-apart, generally parallel relationship;
• aligning said conducting element substantially perpendicular to said blades;
• clamping said conducting element at spaced locations along its length to said spring clips of each blade;
• and
• encapsulating said conducting element and the conducting element support spring clip portion of each of said blades with a solid unitary body of electrically insulating material so that the external surfaces of said element and said blade spring clip portions are in intimate contact with said material.

The method of making an encapsulated, three-piece solderless plug-in fuse comprising the steps of:

• providing a pair of metal blades and a substantially cylindrical fuse wire, each blade having at one end a terminal portion for being connected into an electrical circuit and at the other end a pair of spaced-apart rear bearing members and a flexibly hinged front bearing tongue between said rear bearing members, each of said rear bearing members having a cradle with a substantially V-shaped cross section for receiving a portion of said fuse wire;
• arranging said blades in spaced-apart, generally parallel relationship;
• aligning said fuse wire substantially perpendicular to said blades;
• bending said tongue away from said pair of rear bearing members in each blade to provide an opening between said tongue and said pair of rear bearing members;
• inserting said fuse wire through said opening into said cradle of each of said rear bearing members;
• releasing said tongue in each blade against said fuse wire whereby said fuse wire is clamped in self-aligning, vibration resistant engagement between said front bearing tongue and said pair of rear bearing members to provide a solderless electrically conductive path from one of said blades through the fuse wire to the terminal portion of the other of said blades;
• and
• encapsulating said fuse wire and a portion of each of said blades with a solid unitary body of electrically insulating transparent thermoplastic material so that the external surfaces of said wire and said bearing members and bearing tongue are in intimate contact with said material.

The method of making a three-piece electrically conducting component comprising the steps of:

• (a) forming at least one pair of spaced-apart blades in a sheet stock of electrically conducting metal, each blade having at one end a terminal portion for being connected into an electrical circuit and at the other end a pair of spaced-apart rear bearing members and a flexibly hinged front bearing tongue between said rear bearing members, each of said rear bearing members having a cradle with a substantially concave cross section for receiving a wire therein;
• (b) forcing said hinged front bearing tongue outwardly away from said rear bearing members of each blade to provide an opening between the distal end of said front bearing tongue and the cradles of said rear bearing members;
• (c) inserting a wire into said opening between the distal end of said front bearing tongue and the cradles of said rear bearing members in each blade so that the wire segment extends across the space between the blades;
• (d) relieving the force applied in step (b) to permit said front bearing tongue to move back toward said rear bearing members and force said wire segment against said cradles of said rear bearing members whereby the wire is securely clamped between the pairs of metal blades.

An apparatus for making a three-piece electrically conducting component having one pair of spaced-apart blades with a wire clamped across said blades between rear bearing members and a flexibly hinged front bearing tongue, said apparatus comprising:

• a progressive die having a plurality of stations wherein a strip of metal is moved through said die from station to station, and having punch and die means in at least one of said stations for forming said spaced apart pair of blades with said rear bearing members and said tongue formed therein;
• a wire insertion station in said progressive die having a lower projecting pad and an upper movable plate generally parallel to and spaced from said projecting pad, said plate and pad adapted to receive a pair of said spaced apart blades therebetween, said pad being adapted to project between the rear bearing members of each blade and contact a portion of said tongue when said upper plate is moved downwardly to force said blades downwardly and thereby force said tongue against said pad upwardly away from said rear bearing members to form a wire receiving opening therebetween;
• and
• means for inserting said wire into said opening in each blade of each said pair of blades, said means including at least a first wire carrying member and a second wire carrying member adjacent said progressive die at said wire insertion station, said first and second members being movable generally perpendicular to the direction of travel of said metal strip through said progressive stamping die, said first member having a wire receiving shoulder and said second member having a wire receiving shoulder oriented generally oppositely facing from said shoulder of said first wire carrying member, said wire inserting means further including means for moving said first member towards said wire insertion station to a predetermined distance therefrom and means for moving said second member towards said wire insertion station to a second predetermined distance therefrom which is less than said first predetermined distance whereby the shoulder of said second member moves the wire off of the shoulder of said first member and into the opening of said blades.