Cycling resistant fusible element for electric fuses
AssigneeGould Inc.
InventorRanda Tawfik
Life of this patent
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Abstract
A fusible element having an ability to withstand a large number of on-off cycles is provided. The element comprises a ribbon of copper without any M-effect causing means. The element is bent in a zig-zag shape to establish a plurality of contiguous planar sections enclosing obtuse angles with each other and forming straight edges of the loci of intersection of the planes defined by the planar sections. The straight edges are non-perforated to maximize their flexure strength. Each of the planar sections is provided with at least one point of reduced cross-section remote from the straight edges. The ribbon of copper is electro-plated with sulfamate of nickel forming a dull, ductile layer of nickel.
Claims3
A cycling resistant fusible element for electric fuses comprising
- (a) a ribbon of copper from which any M-effect overlay is absent;
- (b) said ribbon being zig-zag shaped to establish a plurality of contiguous planar sections enclosing obtuse angles with each other and forming straight edges at the loci of intresection of the planes defined by said sections;
- (c) said straight edges being non-perforated to maximize the flexual strength thereof;
- (d) said sections each having at least one point of reduced cross-section remote from said straight edges;
- (e) said ribbon being electroplated with sulfamate of nickel to prevent its oxidation and providing a dull protective layer of high ductility;
- and
- (f) the thickness of said layer being in the order of ten thousandth parts of an inch.
A method for manufacturing cycling resistant fusible elements comprising the steps of
- (a) stamping perforations into a planar ribbon of copper to establish a plurality of serially arranged points of reduced cross-section;
- (b) thereafter electroplating said ribbon with sulfamate of nickel to a thickness in the order of ten thousandth parts of an inch;
- and
- (c) thereafter bending said strip of copper between said points of reduced cross-section at obtuse angles to zig-zag shape.
Dependencies are inferred from the claim text.