JPH03285230A - Irreversible color changeable fuse - Google Patents

Abstract

PURPOSE:To discriminate a blown fuse from among a number of fuse circuits at sight for facilitating replacement of the fuse, by providing the circuits with a nearly material which changes its color irreversibly with the temperature rize of the fuse part. CONSTITUTION:In a card type fuse used for an automobile or the like, separate ends of a fuse metal 1 having thin fuse parts 1a are fixed to a transparent insulation base part 2, and the whole body of the fuse is covered with a transparent insulation cover 3. In this constitution, a completely irreversible temperature indicating material 4 is attached to the thin fuse part 1a for the whole body including other fuse parts 1a parallel to it. When any of the fuse parts 1a is blown, therefore, the color of the temperature indicating material 4 at the part is changed, and the position of the fuse part 1 blown can be decided easily. For the color change, there are types of those from white to dark red, from pink to black, etc., and any of these can be selected.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a fuse that is inserted into an electrical circuit of an electrical device for the purpose of protecting the circuit, and that fuses itself and breaks the circuit due to heat generated by abnormal overcurrent. It is.

(Prior Art and Problems to be Solved) There are various types of fuses for protecting the electrical circuits of electrical equipment. ``Heads with tabs for power distribution'' (JI
SC8313), a type in which the fusible fuse part is enclosed in a cylindrical glass tube and the conductive metal parts at both ends are inserted into the holder.
Cylindrical fuse J for wiring (TJIS C8314), "screw-in type fuse for wiring" that is inserted into a holder in the form of a circuit "plug-type fuse J for wiring"
(JIS C8319) or "Blade type fuse J" (JASO
D19B? ), and recently, card-type devices are also used in which fusible links are formed between terminals and multiple fuse circuits are formed from flexible printed boards (for example, Utility Model Application No. 63-123038, Japanese Patent Publication No. 59-424
No. 79, Japanese Patent Publication No. 1-28 [1784].

Fig. 2 is an explanatory diagram of an example of a conventional card-type fuse, in which (A) is a top view and (rl) is a top view of Fig. 2 (A). 2-X
FIG. 2 is a sectional view. In the drawings, (the opening is a metal fuse, (1a) is the fuse part, (2) is a transparent insulator base, and (3) is a transparent insulator cover.

In the above-mentioned prior art fuse, especially the card-type fuse as shown in FIG. 2, the fuse part is thin;
If there are a large number of fuses in a row, even if one of the fuses blows due to an increase in heat generation temperature due to an abnormal overcurrent, it may be difficult to tell which fuse has blown.

(Means for Solving the Problems) The present invention provides an irreversible color-changing fuse that solves the above-mentioned problems, and is characterized by a substance that irreversibly changes color as the temperature of the fuse part increases. This is due to the fact that it is placed close to the fuse part.

FIG. 1 is an explanatory diagram of a specific example of a card-type fuse similar to that shown in FIG. 2 to which the present invention is applied; FIG.
El) is a sectional view taken along line LX in Figure (A). In the drawings, the same symbols as in FIG. 2 represent the same parts. As shown in the drawing, a layer (4) of a temperature-indicating substance that irreversibly changes color as temperature rises is placed on a transparent insulator cover (3) located directly above the fuse part (la) of the fuse metal (1). It is a provision.

(Function) In the fuse of the present invention, as shown in FIG. 1, for example, by arranging a layer of material that irreversibly changes color as temperature rises on the fuse part, abnormal current may flow for some reason and cause Even if one of the fuses blows due to heat generation or temperature rise, if you take the fuse out, you can clearly see that the blown fuse has changed color due to the temperature rise.

Therefore, the fuse in question can be selected very easily from a large number of fuses lined up and replaced with a new one.

(Example) An example implemented on a wiring board of a combination e-meter of an automobile shown in FIG. 3 will be described. (11) is a flexible printed board, (12) is the flexible printed board (I
I) Card-type FPC fuse incorporated in a part of (1)
3) is the wiring connector that connects to the fuse. A card-type FPC fuse is used with a metal part that is easily melted by Joule heat generated when an overcurrent flows, sandwiched between transparent plastic insulators, as shown in Figure 1.

Conventional fuses have very thin metal fuse parts and a large number of fuse circuits, making it difficult to tell which fuse circuit has blown.

Example: A completely irreversible temperature indicating material (8 Yugiken Kogyo, Thermolabel Ll-100, 100
(changes in color from white to dark red at ℃). An overcurrent flowed through the fuse and caused it to blow, but among the many fuses in the circuit, only the fuse in question changed color from white to dark red, making it possible to tell at a glance which fuse had blown.

Example 2: An irreversible temperature-indicating paint (Gamma Kagaku Kogyo, Thermo Check CF-290, which changes color from pale pink to black at 290°C) is applied on the cover of the transparent insulator directly above the narrow fuse part of the card fuse type. Coated and dried. An overcurrent flowed and the fuse blown, but among the many fuses in the circuit, the fuse in question changed color from bright pink to black, so it was possible to tell which fuse had blown with the naked eye.

Example 3: Irreversible temperature-indicating paint (8 Yugiken Kogyo, Irreversible Thermovain) Na 13.130 was applied on the transparent insulator cover directly above the thin fuse part of the card-type fuse.
(change in color from light reddish-purple to bluish-purple at ℃) was applied and dried. An overcurrent flowed and the fuse blown, but among the many fuses in the circuit, the color of the fuse in question changed from reddish-purple to bluish-purple, so it was possible to tell with the naked eye which fuse had blown.

(Effects of the Invention) As explained above, according to the irreversible variable color fuse of the present invention, when an overcurrent flows and the fuse blows, only the fuse concerned changes color. You can tell at a glance whether or not it has fused. Therefore, replacement with a new fuse becomes extremely easy.

In the embodiment, a card-type fuse was taken as an example, but it goes without saying that the present invention is not limited to card-type fuses and can be applied to fuses in general.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a specific example of a card-type fuse to which the present invention is applied, in which (A) is a top view, and (0) is a sectional view taken along the line X and -X in FIG. (A). Figure 2 is an explanatory diagram of an example of a conventional card-type fuse, in which (A) is a top view, and (0) is an X2-X2 diagram in (A).
FIG. FIG. 3 is an explanatory diagram of a wiring board fuse circuit of a combination day meter of an automobile. 1... Fuse metal, la... Heater part, 2...
・Transparent insulator base, 3...Transparent insulator cover 4...
- Irreversible dichromatic material, 11... Flexible printed board, 12... Card type FPC Hines, 13... Connector.

Claims (1)

[Claims] (1) An irreversible variable color fuse characterized in that a substance that irreversibly changes color as the temperature of the fuse portion increases is disposed close to the fuse portion.