JPH11311391A - Electric fusion joint and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect a joint main body outer surface and to cover it by a simple method. SOLUTION: This manufacturing method is to form electric fusion joints 3 individually and independently on at least more than two pieces of connecting ports 2 of a resin joint main body 1. Thereafter after a terminal pin 4 of the electric fusion joint 3 is connected by an electrically conductive wire 6 so that a heating wire of the electric fusion joint 3 is electrically connected in series, the coupler main body 1 is covered with a shrink film 7, and the shrink film 7 is contracted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric fusion joint for connecting resin pipes made of a thermoplastic resin such as polyethylene and polybutene, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In order to protect the outer surface of an electrofusion joint, bagging is performed, and in particular, when an accessory is attached to the outer surface of the electrofusion joint, the following measures have been taken.

[0003] The electric fusion joint is formed by bringing an outer surface of a resin pipe to be connected close to an inner surface of the electric fusion joint, heating the heating wire provided near the inner surface of the electric fusion joint from a terminal pin and heating the electric wire through a terminal pin. This is a joint for connecting a resin tube to a resin tube by fusing the joint with the resin tube. There are various types such as a socket type, an elbow type, a cheese type, and a cap type.

[0004] Of these types of electro-fusion joints, small-diameter joints are obtained by winding a naked heating wire around an inner formed in advance by injection molding, or by winding a heating wire coated with resin around a metal core for injection molding. After that, it is produced by integral molding by injection molding, and is called an A-type electric fusion joint.

[0005] On the other hand, if the nominal diameter becomes large, the development cost of molds and the like will increase dramatically. However, joints such as elbow type and cheese type, for which many demands cannot be expected, are disclosed in
As disclosed in Japanese Patent No. 6391, a simple-shaped socket-like electrofusion joint is attached to the connection port of the resin joint body by butt fusion or the like. being called. In addition, in this joint, it was necessary to energize each of the electric fusion joints joined to the connection port of the joint main body, so recently, the electric connection of the electric fusion joints has been performed by connecting the terminal pins with conductive wires. Electrofusion joints have been developed and are being trialled, in which heating wires are electrically connected in series and only one energization is required.

FIG. 2 shows a conventional type B electric fusion joint that can be fusion-bonded by one energization. This is a cross-sectional view of the cheese type B type electrofusion joint. A socket type electrofusion joint 3 provided with a pair of terminal pins 4 and a heating wire 5 at connection ports 2 of both sleeves of a resin joint body 1. Is butt-fused,
The heating wires 5 of the electric fusion joints 3 of both sleeves are electrically connected in series by connecting the terminal pins 4 with covered conductive wires 6. Therefore, fusion bonding can be performed only by applying a current once from the terminal pin 4 not connected to the conductive wire 6. In addition, since the conductive wire 6 is disposed on the resin joint main body 1, the terminal pin 4 and the conductive wire 6 connected to the terminal pin 4 are prevented from being caught by the conductive wire 6 during work.
Resin cover 8 made entirely of the same resin as the joint resin
Covered with.

[0007]

However, in the case of the type A fusion joint, there is a problem that the terminal pins protruding from the surface are stained and the outer surface of the joint body is flawed. In addition, in the above-mentioned type B electric fusion joint that can be fusion-bonded by a single energization, a resin cover must be separately manufactured according to the size and shape of the joint, and fused to the joint part. There is a problem that it takes a lot of trouble and time.

The present invention has been made in order to solve such a problem, and an object of the present invention is to provide an electrofusion joint which can protect and cover the outer surface of the joint body by a simple method and a method of manufacturing the same. I do.

[0009]

The above object is achieved by an electrofusion joint whose outer surface is covered with a resin film.

[0010] If the outer surface is covered with a resin film,
It is possible to prevent the terminal pins protruding from the surface from being stained and to prevent the outer surface of the joint body from being flawed, and to cover conductive wires laid on the outer surface. When the entire outer surface of the joint is covered with the resin film, the terminal pin may be exposed by cracking the resin film in the terminal pin portion at the time of energization.

In particular, if the resin film is a shrink film, it is more convenient since the resin film may be covered and heated and heated.

In order to manufacture a B type electric fusion joint which requires only one energization, at least two or more connection ports of the resin joint body are independently formed with an electric fusion joint, and the electric fusion joint is electrically connected. After connecting the terminal pins of the electrofusion joint with conductive wires so that the heat wires are electrically connected in series, the joint main body may be covered with a shrink film to shrink the shrink film.

[0013]

FIG. 1 shows an embodiment of a method for manufacturing a type B electrofusion joint according to the present invention. In FIG.
(A) is a state in which the electric fusion joints 3 are joined to the two connection ports 2 of the resin joint body 1 and the terminal pins of each electric fusion joint are connected by a conductive wire, and (b) is a shrink film to the conductive wire. And (c) shows a state where the shrink film is heated and shrunk.

First, as shown in FIG. 1A, a socket-type electric fusion joint 3 provided with a pair of terminal pins 4 and a heating wire is provided at two connection ports 2 of an elbow-type resin joint main body 1.
Are bonded by butt fusion or the like. Then, the terminal pins 4 are connected by the conductive wires 6 so that the heating wires of the respective electric fusion joints 3 are electrically connected in series.

Next, as shown in FIG. 1B, the conductive wire 6 is covered with a shrink film 7. Finally, as shown in (c), the shrink film 7 is shrunk by heating.

[0016] In this way, a B type electric fusion joint which requires only one energization can be manufactured.
Therefore, it is possible to prevent an accident such as being caught on the conductive wire 6 during operation.

[0017]

Since the present invention is configured as described above, the outer surface of the joint body can be protected by a simple method,
An electrofusion joint that can be covered and a method for manufacturing the same can be provided.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a method for manufacturing an electro-fusion joint according to the present invention.

FIG. 2 is a view showing a conventional B type electric fusion joint capable of performing fusion bonding by one energization.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Resin joint body 2 Resin joint body connection port 3 Electric fusion joint 4 Terminal pin 5 Heating wire 6 Conductive wire 7 Shrink film 8 Resin cover

Claims (3)

[Claims] 1. An electrofusion joint having an outer surface covered with a resin film. 2. The electrofusion joint according to claim 1, wherein the resin film is a shrink film. 3. An electric fusion joint is independently formed at at least two or more connection ports of a resin joint main body, and the electric fusion joint is electrically connected in series with the electric heating wire of the electric fusion joint. A method of manufacturing an electro-fusion joint, in which after connecting terminal pins of the joint with a conductive wire, the joint main body is covered with a shrink film and the shrink film is shrunk.