JPS6029298Y2 - Fireproof wire branch connection - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a branch connection part of a fire-resistant electric wire, and is intended to reduce material costs and processing time at the branch connection part, and to exhibit stable fire resistance performance.

Conventional branch connections for fireproof wires have a structure in which a rubber tape layer, which does not have good fluidity even at high temperatures, is provided on the fireproof layer to prevent the outermost vinyl mold from penetrating into the conductor, or a rubber tape layer that does not flow well even at high temperatures is placed on the fireproof layer to prevent the outermost vinyl mold from penetrating into the conductor. A structure in which a tape made of flexible polyethylene or the like is provided between the fireproof layer and the outermost layer has been proposed.

However, recently, the number of connecting wires at branch connections of fireproof electric wires has tended to be multi-core and large in size. etc., which was a major drawback.

The present invention has been made to eliminate these drawbacks, and instead of directly providing a self-adhesive rubber tape or a vinyl mold layer around the outer circumference of the rubber tape to the core conductor connection portion of a multi-core fireproof electric wire, By providing a hollow part inside through the cover, in the event of a fire, the carbide of the vinyl mold can fall together with the hollow cover without remaining in the branch part, and the hollow part can suppress heat conduction. , it is possible to save materials and shorten working time without using a large amount of tape as in the past, and to exhibit stable fireproof performance.

Below, the present invention will be explained based on the drawings.
In the figure, a is the main line of the refractory electric wire, and b is its branch line.The sheath 1 of each wire a and b is stripped, and the insulator 2 and refractory layer 3 are applied to each wire core in stages, as shown in Figure 2. Then, each exposed conductor 4 is crimped and connected with a connecting terminal fitting 5, and a fireproof layer 6 made of mica glass tape or the like is provided around the entire circumference of the metal fitting 5 and the exposed conductor 4, and furthermore, a self-bonding rubber tape or the like is provided. An insulating layer 7 is provided to form a wire core connection portion 8.

Figure 1 shows a hollow cover 9 covering a plurality of the above-mentioned core connection parts 8, covered with a self-adhesive rubber tape 10 as a protective layer, and injection molded as the outermost layer. A vinyl mold layer 11 is provided.

The hollow cover 9 is made of olefin resin such as polyethylene or polypropylene, and as shown in FIG. 3, a small-diameter cylinder 9b is connected to at least one end of a large-diameter cylinder 9a, and the hollow cover 9 is connected by a hinge 9c. It is cut in half to accommodate changes in the number of wire cores and size.

That is, this hollow cover 9 is made in several types with different dimensions, the applicable range is determined depending on the size of the branch connection, and the length and diameter are cut to match each use with scissors. It is.

When a fire resistance performance test was conducted on the branch connection according to the present invention along the fire temperature curve of JISA1304,
The outermost vinyl mold layer 11 burns first and remains in the branch as a carbide, but the rubber tape 10 inside it burns.
When the hollow cover 9 starts to burn, it falls down together with the carbide of the vinyl mold layer because it has high fluidity.

We conducted various studies on the conditions for this melting and falling, and found that when cables with three or more cores are connected all at once, the volume constituted by the hollow part, the hollow cover 9, and the rubber tape 10 is relative to the overall capacity of the coating layer at the connection part. It was found that when the amount of carbon dioxide exceeds 20%, it tends to fall together with the carbide in the fire resistance test, and the insulation resistance value in terms of fire resistance is good.

The reason for this is that vinyl carbide normally has conductivity, which causes a decrease in the insulation resistance of the connection part, but in the case of the present invention, the vinyl carbide remains in the branch connection part for a short time, and the hollow cover 9 This is because it falls quickly.

On the other hand, if the above-mentioned volume exceeds 50%, the branch connection becomes large, resulting in wasted processing steps and material costs, and does not have a large effect on fire resistance, so it is preferable to keep it below 50%.

As described above, the present invention connects each core conductor of a multicore fireproof electric wire, provides a fireproof layer and an insulating layer thereon, and then covers each core wire together with a hollow cover made of polyolefin resin. This hollow cover is covered with a self-adhesive rubber tape or the like, and a vinyl mold layer is provided around the outer periphery.By interposing this hollow cover,
It is possible to reduce the number of connection process steps and material costs, and to provide a branch connection that exhibits stable fire resistance regardless of the skill level of the operator.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of a branch connection part of a fireproof electric wire showing an embodiment of the present invention, FIG. 2 is a sectional view of a main part of a core connection part thereof,
FIG. 3 is a perspective view of the hollow cover. a... Main line of fireproof electric wire, b... Branch line, 4... Exposed conductor, 6... Fireproof layer, 7
...Insulating layer, 8... Core connection part, 9.
...Hollow cover, 10...Rubber tape,
11... Vinyl mold layer.

Claims (1)

[Scope of utility model registration request] Each core conductor of a multi-core fireproof electric wire is connected, a fireproof layer and an insulating layer are provided on top of it, and a hollow cover made of polyolefin resin is placed over each core, and this hollow cover has self-bonding properties. A branch connection part of a fire-resistant electric wire, characterized in that the branch connection part is covered with a rubber tape having a rubber tape, and a vinyl mold layer is provided on the outer periphery of the branch connection part.