JPH11320687A - Terminal pins for electrofusion joints - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To provide a terminal pin of an electrofusion joint for making a contact pin and a proximal end contact of a resistor without contact failure, and for an outer peripheral portion of a distal end side of the contact pin and a distal end contact of a resistor. That the insulator can be easily assembled around the outer periphery of the SOLUTION: In a terminal pin 13 of an electrofusion joint, a resistor 2 inserted into a buried portion 21A of a contact pin 21 is provided.
2 is joined to the contact pin 21 through the small hole 21B, and the insulator 23 is connected to the tapered portion 21 of the contact pin 21.
C which is pushed in along C and locked on the reduced diameter locking portion 21D.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal pin of an electric fusion joint (electrofusion joint) used for joining water and sewer pipes, gas pipes, deformed pipes and the like made of a thermoplastic resin.

[0002]

2. Description of the Related Art Conventionally, as described in JP-A-64-74381, a heating wire is embedded in the inner surface of a joint body as an electric fusion joint for joining polyethylene (PE) pipes and the like. There is a type in which a pipe to be joined is inserted into a main body, the fitting contact surface (fusion interface) between the joint main body and the pipe to be joined is heated and melted by the heat generated by the heating wire, and the pipe to be joined is fused to the joint body.

[0003] In this electrofusion joint, the time for energizing the heating wire for ensuring proper fusion between the pipe to be joined and the joint body varies depending on the diameter of the joint (the diameter of the pipe). For this reason,
In the prior art, a resistor having a resistance value corresponding to the energization time corresponding to the diameter of the joint is built in a terminal pin (energization terminal) provided in the joint body, and the energization control device connects the heating wire to the heating wire through the terminal pin. At the time of energization, a technique of detecting a resistance value of the resistor and energizing the heating wire for a time determined based on the detected resistance value is employed.

[0004] In the prior art, as described above, contact pins, as described in Japanese Patent Application Laid-Open No. 5-124110,
The resistor, which is embedded so that the proximal contact contacts the contact pin and positions the distal contact outside the contact pin, and covers the outer peripheral portion of the distal end of the contact pin and the distal contact of the resistor There is an insulator having an insulator.

[0005]

However, the conventional terminal pins have the following problems. When a resistor is buried in a contact pin, the base contact of the resistor cannot be joined to the contact pin by soldering or the like.

[0006] A tapered portion having a large diameter toward the distal end is provided on the outer peripheral portion on the distal end side of the contact pin, and a resistor embedded in the contact pin is inserted into a mold, and the tapered portion of the contact pin is inserted. An insulator is injection-molded around the outer peripheral portion of the contact on the tip end side of the resistor to prevent the insulator from falling off from the contact pin. This complicates the manufacturing process of the terminal pins. In addition, when the insulator is subjected to injection molding, a high temperature and a high pressure are directly applied to the resistor, and there is a fear that the resistor may be cracked or damaged.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a terminal pin of an electrofusion joint, wherein the contact pin and the proximal end contact of the resistor are brought into contact without poor contact, and the outer peripheral portion of the distal end of the contact pin and the distal contact of the resistor are contacted. Is to be able to easily assemble an insulator around the outer peripheral portion of the base.

[0008]

According to a first aspect of the present invention, there is provided a contact pin and a resistor which is buried so that a proximal contact is brought into contact with the contact pin and a distal contact is located outside the contact pin. A terminal pin of an electrofusion joint having a body and an insulator covering the outer peripheral portion of the distal end of the contact pin and the outer peripheral portion of the contact on the distal end side of the resistor. A small hole that penetrates to the embedded portion of the resistor is provided, and the resistor inserted into the embedded portion of the contact pin is joined to and integrated with the contact pin from the small hole. A tapered portion having a small diameter toward the distal end, and a reduced diameter locking portion provided on the distal end side of the large diameter base portion of the tapered portion, and an insulator is pushed in along the tapered portion of the contact pin to reduce the diameter. It is designed to be locked to the locking portion.

[0009]

According to the first aspect of the present invention, the following operations are provided. By utilizing the small hole provided at the base end of the contact pin, the resistor inserted into the embedded portion of the contact pin can be firmly joined to the contact pin from the small hole by soldering or welding. As a result, the contact pin and the proximal end contact of the resistor can be brought into contact with each other without poor contact.

After processing the insulator, the insulator is inserted along the tapered portion of the contact pin, and is engaged with the reduced diameter engaging portion. An insulator can be easily assembled around the outer peripheral portion of the tip side contact.

[0011]

FIG. 1 is a schematic view showing an electrofusion joint, and FIG. 2 is a schematic view showing a terminal pin.

[0012] As shown in FIG.
A joint body 11 made of E resin, and a heating element 12 such as a heating wire embedded in a fusion interface on an inner periphery excluding both ends of the joint body 11
And a pair of energizing terminal pins 13 erected on the outer surface of the joint body 11 and connected to the heating element 12.

The terminal pins 13 are, as shown in FIG.
A contact pin 21; a resistor 22 buried so that the proximal contact 22A is brought into contact with the contact pin 21 and the distal contact 22B positioned outside the contact pin 21; Contact 22B on the tip side of body 22
And an insulator 23 that covers the outer peripheral portion.

Here, for the terminal pin 13,
At the base end of the contact pin 21, a small hole 21B penetrating to the resistor buried portion (buried hole) 21A of the contact pin 21 is provided, and the resistor 22 inserted into the buried portion 21A of the contact pin 21 is inserted into the small hole 21B. Contact pin 2 by soldering or welding
1 and integrated. In addition, the small hole 21B functions as an electric caulking hole for connecting the heating element 12 to the contact pin 21.

In the terminal pin 13, a tapered portion 21 C having a smaller diameter toward the distal end side of the distal end outer peripheral portion of the contact pin 21, and a diameter reducing member formed on the opposite distal end side of the outer diameter base of the tapered portion 21 C. A stop 21D is provided. On the other hand, insulator 2
Reference numeral 3 denotes a tapered portion 23A corresponding to the tapered portion 21C of the contact pin 21, a locking portion 23B corresponding to the locking portion 21D, and an inner diameter portion 23C corresponding to the outer diameter of the resistor 22. And, the insulator 23 is a tapered portion 21 of the contact pin 21.
The tapered portion 23A is elastically deformed and inserted along C, and the locking portion 23D of the contact pin 21 can lock the locking portion 23B.

Here, the contact pin 21 is made of a metal such as brass, and is obtained by cutting a round bar. The contact pin 21 has a flange 21E on the outer periphery on the base end side, and the joint body 1
1 can be prevented from falling off when embedded.

As the resistor 22, a cylindrical metal film resistor or a carbon film resistor is used.

The insulator 23 is preferably made of a resin such as polyacetal or polyethylene, and is obtained by cutting a round bar or a cylindrical body.

Therefore, the electrofusion joint 10 is used as follows. (1) Both ends of the joint body 11 of the electrofusion joint 10 are
The tube is inserted, and the connector of the power supply control device is inserted into the terminal pin 13. The connector of the energization control device is disclosed in
As described in JP-A-129493, it has a first contact and a second contact, and the first contact is a contact pin 21 of the terminal pin 13.
Then, the second contact is brought into contact with the resistor 22 of the terminal pin 13.

(2) The heating element 12 is energized through a pair of terminal pins 13 connected to the connector of the power supply control device.
1 PE resin and the outer surface layer of both PE tubes are melted,
The electric fusion joint 10 and the two PE tubes are fused.

(3) At the same time as the above (2), the power supply control device detects the resistance value of the resistor 22 and supplies power to the heating element 12 for a time determined based on the resistance value. Prevent shortage and overheating to ensure proper fusion.

Therefore, according to the present embodiment, the following effects are obtained. Utilizing the small hole 21B provided at the base end of the contact pin 21,
The resistor 22 inserted into the embedded portion 21A of the contact pin 21 can be firmly joined to the contact pin 21 from the small hole 21B by soldering or welding. Thereby, the contact pin 21
And the base contact 22A of the resistor 22 can be brought into contact with each other without any poor contact.

After processing the insulator 23, the insulator 2
3 is inserted along the tapered portion 21 </ b> C of the contact pin 21 and is locked by the reduced diameter locking portion 21 </ b> D, so that the outer circumference of the distal end side of the contact pin 21 and the outer circumference of the distal end contact of the resistor 22 are rotated. The insulator can be easily attached to the device.

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and the design may be changed without departing from the scope of the present invention. The present invention is also included in the present invention.

[0025]

As described above, according to the present invention, in the terminal pin of the electrofusion joint, the contact pin and the proximal contact of the resistor are brought into contact with each other without poor contact, and the outer peripheral portion of the contact pin on the distal end side is contacted. An insulator can be easily assembled around the outer peripheral portion of the contact on the tip end side of the resistor.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an electrofusion joint.

FIG. 2 is a schematic view showing a terminal pin.

[Explanation of symbols]

 13 Terminal Pin 21 Contact Pin 21A Resistor Embedded Part 21B Small Hole 21C Taper Part 21D Reduced Diameter Locking Part 22 Resistor 22A Base Contact 22B Tip Contact 23 Insulator

Claims (1)

[Claims] 1. A contact pin, a resistor buried so as to bring a proximal contact into contact with the contact pin and a distal contact located outside the contact pin, an outer peripheral portion of the distal end of the contact pin and a tip of the resistor In the terminal pin of the electrofusion joint having an insulator covering the outer peripheral portion of the side contact, a small hole is provided at a base end portion of the contact pin to penetrate to a resistor embedded portion of the contact pin, A resistor inserted into the buried portion of the contact pin and integrated with the contact pin through the small hole, and a taper portion having a small diameter toward the tip side at a tip outer peripheral portion of the contact pin; A reduced diameter locking portion is provided on the opposite end side of the large diameter base of the portion, and an insulator is pushed in along the tapered portion of the contact pin and locked to the reduced diameter locking portion. Terminal pin for electric fusion joint.