JPS5850603Y2 - electric wire fuse - Google Patents

Description

[Detailed Description of the Invention] The present invention is concerned with the improvement of a discharge-type electric wire fuse used in low-voltage service lines for the purpose of protecting customers, etc., and is intended to provide a structure particularly suitable for interrupting large currents.

In recent years, closed-type electric wire fuses in which the fuse element is covered with an insulating tube are often used for low-voltage service lines.

However, these devices are connected directly to the service line, and are preferably small and lightweight.

For this reason, the internal volume of the insulating cylinder is made as small as possible,
Such a discharge type fuse discharges the arc generated at the time of interruption to the outside of the insulating cylinder to perform the interruption, so it is difficult to interrupt large currents (
If a short circuit current of several hundred amperes (from several thousand amperes) occurs, the sudden increase in internal pressure will lead to destruction of the insulating cylinder.In other words, the delay in pressure relief action will not only cause the insulating cylinder to be destroyed, but also cause damage to the insulating cylinder. The wires may sag, and even before the wires break, the insulation cylinder may become contaminated due to the pressure release delay, resulting in a decrease in dielectric strength.

This proposal relates to a wire fuse that eliminates the drawbacks caused by the pressure release delay.The fuse element is provided in the center of the connection part, and the connection parts at both ends are connected together so that the element is located in the central space. The fuse element is characterized by being fixed to each side end of the frame-shaped support body by penetrating the fuse element, and further covering the fuse element with a flexible insulating cylinder so as to quickly release the pressure due to the increase in internal pressure when a large current is cut off. It is something to do.

Examples of the present invention will be described below.

Reference numeral 1 denotes a frame-shaped support having a mechanical strength greater than that of a synthetic resin, and a space 1a is formed in the center of the integrally connected support body, and connections formed by covered electric wires are formed at both longitudinal ends of the frame-shaped support body. A thick support portion 1b is formed which penetrates the portion 2 and supports and fixes it.

2a indicates a covering portion. 3 is a fuse element connected between the connecting parts 2, and is located in the space 1a.

4 is an insulating tube made of softer material such as vinyl acetate, vinyl chloride, nylon, polyethylene, synthetic resin, or rubber, and is attached to the recess 1C of the support 1 to cover the fuse element 3. This expands due to a sudden increase in internal pressure when a large current is cut off, and the contact part A with the support (this part is glued or inserted as necessary) comes off, quickly discharging the arc (pressure) that occurs. Immediately release the pressure to the outside and complete the shutdown (in this case, the insulating cylinder itself may be torn).

As shown in Fig. 4.5.6, 5 is an auxiliary cylinder made of synthetic resin, such as polycarbonate, acrylic resin, or inorganic glass, which can be used as needed, and is tightly adhered to the inside of the insulating cylinder 4 and polymerized to provide insulation. Assists the function of the cylinder and support.

Further, cuts, thin walls, holes, etc. are formed in advance in the auxiliary cylinder 5 to form a pressure relief part 5a for pressure relief.

It is to be noted that it is advantageous in terms of insulation and manufacturing if the insulating tube 4 covers the connecting portion as well, as indicated by A (dotted chain line) in FIG.

Further, if the insulating tube 4 and the auxiliary tube 5 are made transparent as necessary, there is an advantage that the internal fusion state can be confirmed.

As described above, the present invention has a simple structure and can be manufactured at low cost.The pressure at the time of shutoff can be quickly released outside the bay by deforming the soft insulating cylinder, which is different from the conventional pressure relief. In addition to being able to eliminate defects caused by delays, since the connection part is supported as a block by the support, there is no twisting of the element, sagging of the wire, etc., and the soft insulating tube prevents flying objects such as small fragments. It is highly safe and has a great practical effect because it can be restricted as much as possible.

[Brief explanation of drawings]

Fig. 1 is an external view showing the electric wire fuse of the present invention, Fig. 2 is a vertical sectional view with main parts cut away, and Fig. 3 is a-a in Fig. 1.
'Cross-sectional view, Figure 4 is an external view showing another embodiment of the present invention,
FIG. 5 is a longitudinal cross-sectional view of the main part, and FIG. 6 is a cross-sectional view taken along line a-a in FIG. 4. 1...Support, 1a...Space, 1b
...Supporting part, 2...Connecting part, 3...
...Fuse element, 4...Insulation tube.

Claims (1)

[Scope of utility model registration request] A fuse element 3 is positioned in the central space 1a of a frame-shaped support 1 having thick support parts 1b at both ends, and a connecting part 2 of the covered electric wire inserted from the support parts 1a at both ends is connected to the fuse element 3.
A soft insulating cylinder 4 is attached to the outer surface of the frame-shaped support 1 so as to be fitted onto the both end supports 1b with the contact parts A, and the insulating cylinder 4 A wire fuse characterized in that the space 1a is sealed so that abnormal internal pressure can be released to the outside.