Abstract Wound film capacitor and method of making wherein at least two layers of shrinkable thermoplastic dielectric are sandwiched between two layers of metalized or, preferably, foil, electrodes. A pair of lead wires are then positioned against the outer surfaces of the foils and rotated together in the manner of mandrels to wind the film and foil layers into a capacitor body. Flat, or otherwise deformed portions formed on a short portion of one end of each lead wire which is outside of the capacitor during winding are then drawn into the center of the capacitor by pulling on the other end of the wires. The capacitor body is then heated to shrink the dielectric and thereby cause the leads to be held in extremely firm engagement with the foil layers. Since the foils encircle at least 270* of the periphery of the lead wires, a very firm, low resistance, pressure bond is made which renders the capacitor able to withstand substantial amounts of heat applied during a soldering operation. The elimination of mandrel holes allows the capacitor to be extremely compact and usable for many applications without the addition of additional thicknesses of sealing materials.
A method of making a wound capacitor comprising the steps of: placing at least a pair of thermoplastic dielectric strips and a pair of metallic electrode layers between a pair of lead wire members so that the at least two layers of dielectric are sandwiched between the pair of electrode layers with said electrode layers each contacting one of said pair of lead wire members, said lead members being axially elongated and positioned transversely of said dielectric strips; rotating said lead wire members together as a unit to wind said thermoplastic dielectric strips and said electrode layers into a capacitor body; providing the capacitor body with outer wraps of plain dielectric; sealing the outside wraps of the capacitor to each other; sliding said lead wire members axially relative to said capacitor and moving a deformed portion of each of said lead wire members from a position outside said capacitor body to a position inside said capacitor body; and heating said capacitor to shrink said thermoplastic dielectric and cause it to force said electrode layers into firm engagement with said lead wires.
Claim 2
Independent Claim
181 words
A method of making a wound capacitor comprising the steps of: placing at least a pair of thermoplastic dielectric strips and a pair of metallic electrode layers between a pair of lead wire members so that the at least two layers of dielectric are sandwiched between the pair of electrode layers with said electrode layers each contacting one of said pair of lead wire members, said lead members being axially elongated and positioned transversely of said dielectric strips; rotating said lead wire members together as a unit to wind said thermoplastic dielectric strips and said electrode layers into a capacitor body; providing the capacitor body with outer wraps of plain dielectric; sealing the outside wraps of the capacitor to each other; sliding said lead wire members axially relative to said capacitor and moving a deformed portion of each of said lead wire members from a position outside said capacitor body to a position inside said capacitor body; and heating said capacitor to shrink said thermoplastic dielectric and cause it to force said electrode layers into firm engagement with said lead wires.
Claim 3
Dependent Claim
17 words
The method of claim 1 wherein said pair of metallic electrode layers comprise strips of metal foil.
Claim 4
Dependent Claim
35 words
The method of claim 1 wherein each of said electrode layers is wound in firm intimate pressure contact across its entire width with at least 270* of the peripherY of its respective lead wire members.
Claim 5
Dependent Claim
14 words
The method of claim 3 wherein said electrode layers comprise strips of metal foil.
Claim 6
Dependent Claim
12 words
The method of claim 4 wherein said metal foil is tin foil.
Claim 7
Dependent Claim
35 words
The method of claim 1 wherein the pair of dielectric strips are placed between the lead wire members so that terminal ends of the strips of dielectric overlap in the longitudinal direction of said strips.