JPH10281384A - Electric fusion coupling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric fusion coupling which works efficiently and reduces welding defective, by removably projecting a stopper in contact with the end face of a contacted member on the inner circumference of the coupling which contains a heat generator. SOLUTION: An electric fusion coupling 2 contains a heat generator 6 along the inner circumference of faucets 4, 5 which are installed on the both ends of a coupling 3, and each terminal 7 which is connected to its end is projected on the both end of the coupling 3. In this case, a stopper 12 with which the end of a connected member can be contacted is projected to the inner circumference of the central position of the coupling 3. This stopper 12 is almost circular are plate, which is formed by dividing a hallow disk into four parts, and can be removed by adding slight shock. When a piping space is narrow, connected members cannot be inserted in the coupling 3 from the both side, one of connected members is required to be inserted to the end of the coupling 3, by removing the stopper 12 the connected member is inserted in the appropriate position on the inside of a heat generator 6.

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 used for connecting a thermoplastic resin tube or the like.

[0002]

2. Description of the Related Art In a conventional general electric fusion joint, a socket for inserting a thermoplastic resin pipe is provided at both ends of a joint body formed in a short tube shape. ,
A heating element such as a nichrome wire or the like is buried in a substantially spiral shape, and a stopper is provided between receiving holes at both ends to protrude to a height equal to the wall thickness of the pipe. And a boss portion is provided to surround the terminal.

[0003] In this electrofusion joint, the end of the tube is inserted into the socket of the joint body until it comes into contact with the stopper, a power source is connected to the terminal, and when the heating element is energized, the inner peripheral surface of the socket is formed. Melts and fuses to the outer peripheral surface of the tube.

[0004]

However, in the conventional electric fusion joint, in the process of heating the heating element, the heating element is pushed by the pressure of the molten resin, and the heating elements come into contact with each other and short-circuit. Poor fusion may occur due to electrical factors. Further, since the metal material of the heating element and the thermoplastic resin have no chemical adhesion, even if the joint between the joint body and the pipe is sufficient even after the electrofusion, the connection between the heating element and the thermoplastic resin does not occur. There was a possibility that a gap was formed between the terminals and water leaked from around the terminal connected to the heating element.

If the working space is so small that the joint body cannot intervene between the ends of the pipes to be connected (if the length between the ends is shorter than the length of the joint body in the connection direction),
A stopper in the joint body for inserting one pipe to the back of the joint body and then moving the joint body toward the other opposing pipe to insert the end of the other pipe into the joint body. Must be removed with a cutter or the like, which is troublesome.

Further, in this case, since the stopper is removed, an appropriate insertion length of the tube cannot be known, and insufficient strength or poor fusion may occur after fusion. It had to be measured, which was troublesome.

Further, when a power supply terminal is inserted into the inside of the boss surrounding the terminal protruding from the outer peripheral surface of the joint body, the terminals are reliably connected to each other by dust or the like entering the inside of the boss. And there was also a risk that fusion failure due to electrical factors would occur.

The present invention has been developed in view of the above-mentioned conventional problems, and an object of the present invention is to provide an electro-fusion joint having high working efficiency and low fusion defects. .

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to an electrofusion device for melting and bonding a joint body and a member to be connected by the heat generated by a heating element provided on the joint body made of thermoplastic resin. In the fitting joint, a stopper that abuts the end face of the connected member protrudes from the inner peripheral surface of the joint main body so that the stopper can be cut off. This electro-fusion joint has a narrow piping space, so that a connected member cannot be inserted into the joint body from both sides, and even when it is necessary to insert one connected member to the back of the joint body, the stopper is cut with a cutter or the like. Work efficiency is good because it can be easily removed without need.

[0010] In addition, in an electrofusion joint in which a joint body and a connected member are melted and bonded by heat generated by a heating element provided in a joint body made of a thermoplastic resin,
A terminal connected to the heating element was protruded, and a boss was provided to surround the terminal, and a groove was formed on the inner surface of the boss. In this electric fusion joint, the connector of the power supply is fitted into the boss in order to connect the terminal of the electric fusion joint to the terminal of the power supply. The groove provided on the inner surface of the boss has the connector and the boss. A gap can be formed between the boss and the boss so that dust and the like in the boss portion can be discharged to the outside at the time of fitting.

In addition, in an electric fusion joint in which the joint body and the member to be connected are melt-bonded by the heat generated by the heating element provided in the joint body made of thermoplastic resin, a visual recognition part for grasping the insertion length of the member to be connected. Was provided on the joint body. Even if it is necessary to actually measure the insertion length of the connected member for cutting off the stopper, adjusting the interval between the connected members, etc. Without using it, an appropriate insertion length can be grasped on the spot.

Since the heat generating element is covered with the insulating layer, the heat generated by the heat generating element melts the electric fusion joint, and the heat generating element is moved by the melting pressure to move or deform. Never do.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an embodiment of an electric fusion joint according to the present invention. FIG.
1 is a longitudinal sectional view showing an embodiment of the electrofusion joint, FIG. 2 is a sectional view taken along line AA of the electrofusion joint shown in FIG. 1, and FIG. 3 is a side enlarged view of the electrofusion joint shown in FIG. 1. FIG. 4 is a front view showing a use state of the electric fusion joint of FIG. 1, and FIG. 5 is a schematic front view showing an embodiment of a heating element before embedding the electric fusion joint covered with an insulating layer and a thermoplastic resin layer. FIG. 6 and FIG. 6 are cross-sectional views of the heating element shown in FIG. In FIGS. 1 and 2, in order to clarify the presence of the thermoplastic resin layer, the heating element is illustrated as being covered with the thermoplastic resin layer. It is integrally fused with the electric fusion joint.

In FIG. 1, reference numeral 1 denotes a tubular connected member made of a thermoplastic resin, and reference numeral 2 denotes a socket-type electric fusion joint made of a thermoplastic resin. The electrofusion joint 2 is provided with receiving ports 4 and 5 at both ends of a substantially cylindrical joint body 3.
A heating element 6 made of a resistance wire such as a nickel wire, a nichrome wire, an iron chrome wire or the like is embedded along the inner peripheral surface of the heating element 5 in a substantially spiral shape, and each terminal 7 connected to an end of the heating element 6. But,
It protrudes from both ends of the joint body 3. Here, as a thermoplastic resin used as a material of the connected member 1 and the electrofusion joint 2, a polyolefin resin such as polybutene, polyethylene, or polypropylene is preferable, and polyvinyl chloride, polystyrene, or polyolefin is converted to an unsaturated carboxylic acid or Modified polyolefins modified with their anhydrides (eg, maleic anhydride, benzoyl peroxide, acrylic acid, methacrylic acid, etc.) may also be used.

As shown in FIG. 6, the heating element 6 includes an insulating layer 6
a, and a thermoplastic resin layer 6b that melts with the joint body 3 is covered, bent at substantially the center and spirally wound to form a double spiral cylinder as shown in FIG. Buried inside. Since the heating element 6 is covered with the thermoplastic resin layer 6b in this manner, the heating element 6 and the joint body 3 are fused without any gap, and the heating element 6 is formed in a double spiral cylindrical shape. The terminals 7, 7 at both ends of the heating element 6 can be projected from substantially the same location of the joint body 3 without crossing the heating element 6. The insulating layer 6a
Is appropriately formed of an electrically insulating material such as cotton, silk, glass fiber, polyurethane, epoxy resin, polyethylene terephthalate, polyesterimide, heat-resistant polyester, polyimide, and polyamideimide.

Reference numerals 8 and 9 denote substantially elliptical cylindrical boss portions which are fitted with a connector portion (not shown) of a power supply to be connected. The boss portions 8 and 9 are terminals 7 and 9 protruding from the surface of the joint body 3, respectively. 7, and protrudes from the surface of the joint body 3. And, on the inner bottom surface and the opposing side surfaces of the bosses 8 and 9,
Grooves 10 and 11 extending from the bottom surface to the opening surface are respectively formed. The grooves 10 and 11 form a gap between the bosses 8 and 9 and a connector (not shown) of a power supply fitted in the bosses 8 and 9, and dust such as dust in the bosses 8 and 9 is formed. It allows for emissions.

Reference numeral 12 denotes a stopper for abutting the end of the connected member 1 and protrudes between the receiving ports 4 and 5 on both sides of the joint body 3, for example, on the inner peripheral surface of the joint body 3 at the center position. As shown in FIG. 3, the stopper 12 is a substantially arc-shaped plate obtained by dividing a hollow disk into four parts, and is formed on the joint body 3 through ribs 13 protruding from both sides of the peripheral surface and three places at the center. It is integrally formed on the inner peripheral surface. The width of the stopper 12 is formed substantially equal to the thickness of the connected member 1, and the stopper 1
The inner peripheral surface 2 is substantially the same as the inner peripheral surface of the connected member 1.

Reference numeral 14 denotes a visual recognition part for grasping the insertion length of the connected member 1, which is provided on the outer peripheral surface of a portion of the joint body 3 where the stopper 12 is provided (the center part of the joint body 3). It has substantially I-shaped linear portions 14a, 14a indicating the insertion positions of the end faces of the connecting members 1, 1 and substantially <-shaped arrow portions 14b, 14b indicating the inserting direction of the connected members 1, 1. . Note that the shape of the visual recognition portion 14 is not limited to the above-described shape, and may be any shape as long as the insertion position of the end face of the connected member 1 can be recognized. Alternatively, it may be attached to the entire periphery of the electric fusion joint 2.

Hereinafter, a method of using the above-described electrofusion joint 2 will be described. In the receiving ports 4 and 5 provided at the end of the electrofusion joint 2, the insertion end face of the connected member 1 is inserted into the receiving ports 4 and 5.
The connected members 1 and 1 are inserted until they come into contact with the stoppers 12 provided between the five members.

If it is impossible to create a space between the connected members 1 and 1 to be connected in a length in the joint direction of the electrofusion joint 2, the stopper 12 projecting from the inner peripheral surface of the joint body 3 is provided. It is cut off by applying a light impact such as pressing, and one of the connected members 1 is removed from one of the receiving ports 4 of the electro-fused joint 2 until the electro-fused joint 2 no longer protrudes from the end face of the connected member 1. Connected members 1, 1 to be inserted and connected
And the electric fusion joint 2 is moved to the other connected member 1 side, and the other connected member 1 is inserted from the other socket 5 of the electric fusion joint 2. In this case, the end faces of the connected member 1 are aligned along the linear portion 14a of the visual recognition portion 14 provided on the surface of the joint body 3, and the insertion length of the connected member 1 is confirmed (for example, the outer periphery of the connected member 1). Mark the surface) and then insert. By doing so, the connected member 1 can be inserted into an appropriate position inside the heating element 6.

Next, a connector portion of a power supply (not shown) is fitted into the boss portions 8 and 9, and terminals in the connector portion are connected to terminals 7 in the boss portions 8 and 9. At this time, the air in the boss portions 8 and 9 compressed by the connector portion is exhausted through the grooves 10 and 11 together with the dust and the like in the boss portions 8 and 9.

When electricity is sent from the connected power source to the heating elements 6 and 6, the heating elements 6 connected via the terminals 7 generate heat, and the heat melts the inner peripheral surfaces of the receiving ports 4 and 5, It is fused integrally with the outer peripheral surface of the insertion end of the connected members 1, 1. At this time, the heating element 6 may move and deform as the inner peripheral surface is melted. However, since the heating element 6 is covered with the insulating layer 6a, the heating element 6 is electrically fused without short-circuiting. The inner peripheral surface of the joint 2 and the outer peripheral surfaces of the connected members 1 and 1 can be integrally fused.

[0023]

As described above in detail, according to the present invention, even when the working space is small and the stopper of the electrofusion joint needs to be removed, the stopper can be cut off by a slight impact, so that the work on site can be performed. Time can be reduced.

Further, since a groove is provided in the boss portion to enable dust and the like to be discharged, poor contact between the terminal of the power supply and the terminal of the electric fusion joint can be prevented, and the connected member and the electric fusion joint can be securely connected. Can be fused.

Also, the insertion end face of the connected member can be inserted at an appropriate position without using a measure or the like.
The length of insertion of the connected member into the electrofusion joint can be confirmed on the spot.

Furthermore, even if the heating element is deformed by the melting pressure of the electrofusion joint portion melted by the heating element, a short circuit of the heating element is prevented, and the connected member and the electrofusion joint are reliably fused. You can wear it.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of an electrofusion joint of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a partially enlarged side view of the electric fusion joint.

FIG. 4 is a front view showing a use state of the electric fusion joint.

FIG. 5 is a front view showing an embodiment of a heating element covered with a thermoplastic resin layer or the like.

FIG. 6 is a cross-sectional view of a heating element covered with a thermoplastic resin layer and the like.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Connected member 2 Electric fusion joint 3 Joint main body 4,5 Receptacle 6 Heating element 6a Insulating layer 7 Terminal 8,9 Boss 10,11 Groove 12 Stopper 14 Viewing part

Claims (4)

[Claims] 1. An electric fusion joint in which a joint body and a member to be connected are melt-bonded by the heat generated by a heating element provided in the joint body made of a thermoplastic resin. An electrofusion joint characterized in that a stopper for abutting an end face is protruded so as to be cuttable. 2. An electric fusion joint in which a joint body and a member to be connected are melt-bonded by heat generated by a heating element provided on a joint body made of a thermoplastic resin, wherein the joint body is connected to the heating element on a surface of the joint body. And a boss portion surrounding the terminal, and a groove formed in an inner surface of the boss portion. 3. A visual recognition part for grasping the insertion length of a connected member in an electric fusion joint in which a joint body and a connected member are melt-bonded by heat generated by a heating element provided in a joint body made of a thermoplastic resin. Is provided on the joint body. 4. The electrofusion joint according to claim 1, wherein the heating element is covered with an insulating layer.