JPS596466B2 - Fuse and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuse for protecting electrical and electronic equipment and a method for making the same.

British Patent No. 1,30 of Orbis Smerzkelingen Veraprik N.U.K. dated May 10, 1971
No. 4,629 discloses a fuse element in which a very fine wire is spirally wound around a hard insulating core.

The insulating core serves to support the wire and prevent the wire from sagging, and also provides adequate strength to facilitate handling of the fuse element.

The core must be heat resistant and have good thermal insulation, but it must not continue to burn like an electrical insulator, and it must be thin enough that heat dissipation is negligible.

A thin, hard core made of glass fiber has the required properties and is easy to work with, so it can be made so thin that heat dissipation is almost negligible.

A thin wire is wrapped around this thin, hard core many times at close intervals.

A disadvantage of this type of fuse element, which consists of a thin core supporting a winding of thin fuse wire, is that the electrical resistance is relatively high due to the large number of turns of wire around the core.

The aim of the invention is to eliminate this drawback.

The fuse element of the present invention is formed by winding a thin metal wire many times in a helical manner around a thin flexible core made of fibers having electrical and thermal insulation properties. It is made by short-circuiting multiple windings provided at both ends of a fuse element within a certain portion of the fuse element.

The short-circuited parts of the fuse element are electrically connected to each other by means of an intermediate working winding, the fused link being composed of only a relatively small number of turns of said working winding.

The fuse element according to the invention is particularly suitable for the manufacture of time-delayed fuses which blow at low currents, e.g. 7 amperes or less.

The thin flexible core is preferably made of glass fiber and preferably has a diameter of 0.77rrvn or less.

The thin metal wire preferably has a constant melting point and a diameter of 0.38 m or less.

The fuse element is fixed between the conductive terminals at each end of the cartridge, its shorted part is electrically connected to the terminal, and the intermediate part consisting of the working winding is located in the center of the cartridge, i.e. between the terminals. It's almost in the center.

The present invention also involves winding a thin metal wire in multiple helical turns around a thin flexible core of electrically and thermally insulating fibers, and winding the winding in two spaced longitudinally spaced portions. A method for making a fuse is provided, which comprises shorting a wire, housing the formed fuse element in a cartridge or other container, and bringing the shorted part into electrical contact with terminals at both ends of the cartridge.

The wire-wound core can be made in a continuous process and then cut into predetermined lengths.

Next, a fuse element is formed by short-circuiting the winding portions at both ends or near both ends of the cut wire at a fixed portion in the longitudinal direction.

In addition, the present invention involves winding a thin metal wire in a spiral shape multiple turns around a thin flexible core made of electrically and thermally insulating fibers, and forming continuous longitudinal portions of the winding at intervals. the windings of the fuse element are short-circuited and the core is cut midway between the ends of the continuous longitudinal section so that the short-circuited winding sections at both ends of the fuse element are electrically connected to each other by the intermediate section consisting of the working winding. A method of making a fuse is provided which comprises forming a fuse element connected to a fuse element and then placing the fuse element in a cartridge or other container.

The windings may be shorted by any method.

In embodiments of the invention, the long portions of the windings are metallized with a solder coating, but they may be shorted by any other suitable means.

By shorting out a portion of a fuse element, the electrical resistance of a fuse made by incorporating such a fuse element is considerably reduced.

The short-circuited portion also provides the fuse element with appropriate stiffness, thus making it easier to handle.

Although it is preferred that the thin metal wire be wrapped in multiple closely spaced turns around the flexible core, the wire may be coated with an insulating coating and then wrapped around the core in close coils.

The invention can also be used in such configurations, where the insulating coating of the wire is easily destroyed at the point where it is shorted by applying heat to metallize it.

Insulated wires are particularly advantageous for producing very low current fuses, for example below 250 mA.

The very fine fuse wire used at such low currents tends to be melted by solder when it is metallized, and this tendency can be reduced or avoided by applying an insulating coating.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

In FIG. 1, the fuse element is made by wrapping a thin metal wire 1 (eg copper or silver wire) with a sharp melting point around a thin fiber filament 2 (eg glass fiber).

The wire is wound around the core many times with close intervals.

Continuously spaced longitudinal sections 3 along the core are metallized with a solder coating in order to short-circuit the windings in those sections.

The short-circuited parts 3 are electrically connected to each other by an intermediate part 4 consisting of an unshorted working winding.

A fuse having the fuse element of the present invention can be easily manufactured by automation.

ratio of metallized to non-metalized parts, winding pitch,
By changing the material and diameter of the wire, the diameter of the core, etc., the current rating and melting characteristics can be changed.

The fuse element material according to the invention is cut at an intermediate position between the ends of the metallized parts 3 to form a fuse element in which the metallized parts 3 at both ends are connected to each other by the working winding of the intermediate part 4. I will make it happen.

The fuse element thus produced may be placed in a cartridge or other container made of non-conductive material and electrically connected to the ends that will serve as terminals for connecting the fuse in an electrical circuit.

Such a cartridge type fuse is shown in FIG.

The fuse comprises a tube 6 made of glass or other insulating material, with metal end caps I providing terminals for connecting the fuse to an electrical circuit.

The fuse element 5 is placed within the tube and secured by clamping the ends of the metallized portion 3 at each end of the tube between the end cap and the tube.

A sealing material 8 is placed inside each end cap between the end of the tube and the end wall of the cap to provide a seal.

In the fuse of the present invention, the middle portion of the 40 windings with a relatively small number of turns performs the fuse action, but the electrical resistance is considerably lower than that of a conventional fuse in which a thin metal wire is wound around a flexible insulated core. low.

Furthermore, the metalized portions at both ends of the fuse element serve to give stiffness to the element and also increase ease of handling when assembling the fuse.

Although specific embodiments have been described above, various modifications can be made without departing from the scope of the invention, which is limited by the scope of the claims.

For example, with a slight modification to the embodiment of FIG. 2, the metallized end of the fuse element 5 could be soldered to the center of the end cap 7 instead of being sandwiched between the cap and the end of the tube 6. .

[Brief explanation of drawings]

FIG. 1 is an enlarged view of a part of a fuse having a fuse element according to the present invention, and FIG. 2 is an axial cross-sectional view of a cartridge type fuse according to the present invention. 1...metal wire, 2...core, 3...
・・・Constant part, 4... Intermediate part, 5...
... Fuse element, 6 ... Cartridge, 7.
...Terminal.

Claims (1)

[Scope of Claims] 1. A fuse having a fuse element in which a thin metal wire is wound helically many times around a thin flexible core made of electrically and thermally insulating fibers, the windings being spaced apart from each other. A fuse characterized in that a plurality of winding portions provided at both ends of a fuse element at a constant portion in a longitudinal direction are short-circuited, and the short-circuited portions are electrically connected to each other by an operating winding in an intermediate portion. 2. Claim 1, characterized in that fixed longitudinal parts of the windings are metallized by coating with solder, thereby short-circuiting the fixed longitudinal parts of the windings. Fuses listed. 3. The fuse according to claim 1 or 2, wherein each of the winding parts is wound adjacent to each other, and the operating winding in the middle part is coated with an insulation coating. 4. The fuse according to any one of claims 1 to 3, wherein the diameter of the thin metal wire is 0.77rrvn or less, and the diameter of the core is 0.38m or less. 5. Claims 1 to 5, characterized in that a fuse element is fixed between conductive terminals at both ends of the IJ edge, and the short-circuited portion in the longitudinal direction is brought into electrical contact with the terminals. Fuse according to any of paragraph 4. 6. A method for manufacturing a fuse by winding a thin metal wire in a spiral shape many times around a thin flexible core made of electrically and thermally insulating fibers, and attaching the thus formed fuse element to an insulating cartridge. In this step, the plurality of windings of two longitudinally spaced apart portions of the winding are short-circuited, the formed fuse element is housed in a cartridge, and the two longitudinally constant portions are placed at opposite ends of the cartridge. A method for manufacturing a fuse that is characterized by making electrical contact with a certain terminal. 1 In the fuse manufacturing method, which involves winding a wire around a core and cutting the wire-wound core to a certain length to form a fuse element, both ends or both ends of the fuse element that is cut to a certain length to form the fuse element. 7. A method for manufacturing a fuse as claimed in claim 6, characterized in that winding portions of adjacent windings are short-circuited at fixed lengthwise portions spaced from each other. 8 In the fuse manufacturing method, in which a fuse element is formed by winding a wire around a core and cutting the wire-wound core to a certain length, windings of fixed portions of the windings in the longitudinal direction are spaced apart from each other by a certain distance. and then cutting the wire-wound core at a position midway between the ends of the short-circuited conductive longitudinal section to form a fuse element. A method for manufacturing the fuse described in Scope Item 6. 9 Thin metal wire is insulated and wrapped around a core so that the windings are adjacent to each other, and the insulation of the longitudinal windings placed at regular intervals is removed or destroyed at the short-circuited part. Claims 6 to 8 characterized by
The manufacturing method of the fuse described in any of the paragraphs.