JPS59228336A - Fuse for wire - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wire fuse for preventing accidents by interrupting the circuit when an overcurrent flows in a drop-in line in a power distribution line.

Due to various causes, a relatively small small overcurrent may flow in this type of power distribution line, and a relatively large large overcurrent may flow in this type of power distribution line.

However, in conventional electric wire fuses, one kind of fuse element is usually bent, so it is difficult to make the wire fuses work effectively against both the small overcurrent and the large overcurrent.

In order to eliminate the above-mentioned problems, the present applicant has previously proposed a wire fuse (Utility Model No. 56, U.S. Pat.
-59758).

However, in the above-mentioned electric wire fuse, a high-resistance wire that indicates whether or not the fuse is blown is wrapped around the entire outer circumferential surface of an insulating tube that covers the entire fuse, and is connected in parallel to the fuse element. When a fuse blows out, there is a problem in that it is not possible to determine whether the blowout is due to a small overcurrent or a large overcurrent.

The present invention has been made to solve the above-mentioned problems.The present invention makes it possible to visually see the melting due to a small overcurrent through the transparent insulation tube, and the cutoff due to a large overcurrent is indicated by a display on the surface of the insulating tube. The purpose is to provide a fuse for electric wires that can be confirmed.

The present invention will be described in detail below with reference to the drawings.

First, as shown in FIG. 1, a copper connecting conductor 1 is formed by integrating a large-diameter cylindrical portion 1a and a small-diameter hollow cylindrical portion 1b, and a low-melting fuse element 2 that fuses with a small overcurrent is made of a lead alloy. The low-melting fuse element 2 is made into a rod shape, and the end face of the large-diameter cylindrical portion 1a of the connecting conductor 1 is brought into contact with one end of the low-melting fuse element 2 and welded by soldering.The other end is made of copper, silver, or One end of the large current fuse element 3 made of these alloys is inserted into the hole of the small diameter hollow cylindrical portion 1b of the connecting conductor 1, and the cylindrical portion 1b is compressed to fix the fuse element 3.

Further, a ring-shaped partition plate 4 made of a conductor is fitted into the small diameter cylindrical portion 1b of the connecting conductor 1, and a rod-shaped terminal 5 made of copper having an element insertion hole at one end is inserted into the other end of the fuse element 3. A wire insertion hole 5a that does not pass through is provided at the other end of the rod-shaped terminal 5, and a wire (not shown) is inserted into the rod-shaped terminal 5.
to be able to connect with.

Further, one end of a conductor 6 made of copper or a prepared alloy is connected to the other end of the low-melting fuse element 2, and a rod-shaped terminal 7 made of copper having a conductor insertion hole at one end is placed over the other end of the conductor 6. The other end of the rod-shaped terminal 7 is provided with an electric wire insertion hole 7a that does not pass through so that it can be connected to an electric wire (not shown).

Further, a hollow cylindrical insulating tube 8 is formed of synthetic resin, and this insulating tube 8 is placed between the partition plate 4 and the rod-shaped terminal 5 so as to enclose the fuse element 3 described above. The large current fuse element chamber formed between the Wrap the high resistance wire 10 around the outer circumference of the insulating tube 8,
One end thereof is connected to the rod-shaped terminal 5, and the other end is connected to the conductor 1 via the partition plate 4. As shown in FIG. 1, the outer periphery of the high resistance wire 10 is covered with thermal paper (
Synthetic paper) 11 is wrapped around almost the outer periphery of the insulating tube 8, and a hollow cylindrical synthetic resin transparent cover 12 is used to enclose between the rod-shaped terminals 5 and 7, and both ends of the transparent cover 12 and the rod-shaped terminal 5 are wrapped around the rod-shaped terminals 5 and 7. .7 are respectively closed by insulating lids 14 having fixing fittings 13 that can be compressed and fixed to the rod-shaped terminals 5 and 7 on the inner periphery, and further covered with an elastic material such as synthetic rubber or synthetic resin on the outside. A cap 15 is placed on the transparent cover 12 to seal the space between both ends of the transparent cover 12 and the rod-shaped terminals 5 and 1. Note that 16 is a waterproof sealant applied to these sealing surfaces.

Next, the operation of the apparatus of the present invention constructed as described above will be explained. When a small overcurrent flows through the electrical circuit in which the electric wire fuse is inserted, the low-melting fuse elements 1 and 2 are fused, and this fusion is visible from the outside through the transparent cover 12.

Furthermore, when a large overcurrent flows through this electric wire fuse, the large current fuse element 3 melts and the high resistance wire 10 wound around the outer periphery of the insulating cylinder 8 generates heat, which causes the thermal paper 11 to discolor. By visually observing the discoloration of the thermal paper 11 through the transparent cover 12, it is possible to determine whether the interruption is due to a large overcurrent.

In other words, according to the fuse of the present invention, it is possible to easily and reliably distinguish between a blowout caused by a small overcurrent and a cutoff caused by a large overcurrent.Therefore, when replacing the fuse, the display indicates that the electrical circuit is short-circuited. This has the advantage of making maintenance work easier and safer during replacement work.Of course, this fuse itself is capable of interrupting large currents, so even if the fuse of the present invention is used in a short-circuited circuit. There will be no danger to workers if the connection is made.

Furthermore, although the high resistance wire 10 for display is made of a material with a large resistance, since a small fuse 10a is provided in the middle, if for some reason, for example, a short circuit occurs for a very short time due to an incorrect operation, the fuse element 3 becomes de-energized, and residual load current flows through the display wire 10, but since the small fuse 10a is reliably blown by a small amount of heat, there is no risk of melting or burning out the insulation around the display wire. .

As described above, the electric wire fuse of the present invention does not burn out under any circumstances, and can easily and reliably determine whether the electric circuit is normal or short-circuited by the blown indication. This allows workers to work with peace of mind.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of the fuse for electric wires of the present invention, and FIG. 2 is an explanatory view showing the manufacturing process of the fuse for electric wires of the present invention. 1...Conductor 2...Low melting fuse element 3...Fuse element for high current 4...Partition plate 5...Bar-shaped terminal 6...Conductor 7...Bar-shaped terminal 8...Insulation tube
9... Arc extinguishing agent (silica sand) 10... High resistance wire
10a...Small fuse 11...Thermal paper
12...Transparent cover 13...Fixing metal fittings 14
...Insulating lid 15...Cap 16...Waterproof sealant patent applicant Kinbo Electric Co., Ltd.

Claims (1)

[Claims] A low-melting fuse element that melts at a 1° small overcurrent,
A large current fuse element that melts due to large overcurrent is connected via a conductor with a partition plate, both ends of this connecting fuse element are connected to rod-shaped terminals, and only this large current fuse element is connected to a hollow insulating tube. At the same time, the fuse element chamber formed between the partition plate and the fuse element chamber is filled with arc extinguishing agent, and a high resistance wire with a small fuse inserted in the middle is wound around the outer periphery of this insulating cylinder, and both ends of the wire are wrapped. are respectively connected to the rod-shaped terminal and the conductor having the partition plate,
Thermal paper is wrapped around the outer periphery of this high resistance wire, and the entire connection fuse element including the outer periphery is covered with a transparent cover, and elastic holes are connected between both ends of the transparent cover and the rod-shaped terminal. A fuse for electric wires that is sealed with a cover.