Electric fuse for small current intensities
AssigneeGould Inc.
InventorRichard T. Oakes
Life of this patent
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Abstract
An electric fuse having a printed circuit type fusible element. A substrate of glass textile material impregnated with a polymerized melamine resin and alumina trihydrate is the carrier for the fusible element. The dispersion of the two above referred-to components is formulated to serve as adhesive medium between the glass textile material and its metal covering and as source of arc-quenching gases when subjected to the action of an electric arc. An addition of silane significantly enhances the bonding action of the melamine resin alumina trihydrate dispersion of the glass fiber substrate with the metal layer by which it is clad.
Claims8
An electric fuse comprising
- a. a tubular casing of electric insulating material;
- b. a granular arc-quenching filler inside said casing;
- c. a substrate of glass fibers immersed in said filler and clad by a conductor of sheet metal;
- d. means for connecting said conductor into an electric circuit;
- e. an aqueous dispersion of melamine resin and alumina trihydrate saturating said substrate to perform the dual function of bonding said substrate to said conductor of sheet metal and of evolving arc-extinguishing gases when subjected to the action of an electric arc;
- and
- f. said dispersion further including a small addition of organo-functional silane in the order of 1%-5% by weight of the melamine solids contained in said dispersion.
A method of making a composite substrate for supporting fusible elements of electric fuses which comprises the steps of
- a. saturating at least one glass textile layer with an aqueous dispersion of melamine formaldehyde resin, alumina trihydrate and silane;
- b. depositing at least one metal layer onto said glass textile layer;
- c. compressing said glass textile layer and said metal layer to a pressure ranging from 200-300 pounds per square inch;
- and thereafter
- d. thermally polymerizing said dispersion at a temperature between 280.degree. F-315.degree. F.
Dependencies are inferred from the claim text.