US 3361884 A
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Description (OCR text may contain errors)
Jan. 2, 1968 E. B. PARKES 3,361,884
PRINTED CIRCUIT FUSES Filed Feb. 28, 1967 FIG. 3.
United States Patent 3,361,884 PRINTED CIRCUIT FUSES Eric Bernard Parkes, Selly Oak, Birmingham, England,
assignor to Joseph Lucas (Industries) Limited, Birmingham, England, a British company Filed Feb. 28, 1967, Ser. No. 619,340 Claims priority, application Great Britain, May 20, 1966, 22,546/ 66 4 Claims. (Cl. 200-135) ABSTRACT OF THE DISCLOSURE A printed circuit fuse has an insulating board With a pair of spaced conductive terminal portions thereon interconnected by a fuse portion. The board is shaped so that the fuse portion is supported on a thin neck of insulating material of substantially the same length and breadth as the fuse portion itself, this arrangement minimising distortion by the heat generated in the fuse portion.
This invention relates to fuses.
A fuse according to the invention comprises an insulating board having thereon a layer of conductive material shaped to define a pair of spaced terminal portions interconnected by a fuse portion, the board being so shaped that the fuse portion is supported on a neck of insulating material of substantially the same length and breadth as the fuse portion itself.
In the accompanying drawings FIGURE 1 is a plan view of a fuse construction in accordance with a first example of the invention and FIGURE 2 is a view similar to FIGURE 1 illustrating a second example of the invention.
Referring first to FIGURE 1 there is provided an insulating board 11 having printed on one or both faces thereof a layer 12 of conductive material. The layer 12 is shaped to define a pair of spaced terminal portions 13, 14 interconnected by a narrow fuse portion 15. The board 11 is formed with a pair of generally semi-circular holes 16, the straight edges of which are adjacent opposite sides of the portion 15, the arrangement being such that the portion 15 is supported on a neck 17 of insulating material of substantially the same length and breadth as 3,361,884 Patented Jan. 2, 1968 the portion 15 itself. The narrow fuse portion 15 and the neck 17 are collectively called the fuse strip.
Referring now to FIGURE 2, the layer in this example is printed with the fuse portion 15 adjacent one edge of the board 11 and therefore only one hole 16 is required to isolate a neck 17 of insulating material and form the fuse strip.
It is found that heat generated in the fuse portion 15 causes distortion of the insulating material, such distortion imposes unwanted mechanical stresses on the fuse portion 15 and the construction specified above tend to minimise the distortion.
Having thus described my invention what I claim as new and desire to secure by Letters Patent is:
1. A fuse comprising an insulating board having on at least one side thereof two terminal legs of conductive material interconnected by at least one narrow fuse strip which consists of a continuous underlying neck of said board and a continuous overlying portion of fusible material, said insulating board having at least one hole adjacent to and defining the shape of one side of said strip, and said neck and fusible material portion being coextensive over the entire length of said strip so as to minimise the distortion in said board.
2. A fuse as claimed in claim 1 wherein the conductive material is on both sides of the insulating board.
3. A fuse as claimed in claim 1 wherein there are two holes in the insulating board adjacent to and defining each side of the narrow fuse strip.
4. A fuse as claimed in claim 1 wherein the hole is semi-circular in shape with the diameter adjacent the narrow fuse strip.
References Cited UNITED STATES PATENTS 3 07, 63 7 BERNARD A. GILHEANY, Primary Examiner. H. B. GILSON, Assistant Examiner.