JPH0719386A - Electrical fusion joint - Google Patents

Abstract

PURPOSE:To provide extremely positive fusion-jointing by forming a recessed groove and a protrusion which are thread-engaged mutually with the inner peripheral surface of a socket and the outer peripheral surface of the end part of a synthetic resin pipe which is inserted into and engaged with the socket, thread-engaging the end part of the synthetic resin pipe with the socket, and then supplying power to a heating wire for fusion-jointing. CONSTITUTION:A spiral protrusion 11 is formed on the outer peripheral surface of a synthetic resin pipe 1 at prescribed intervals in the axial direction of the pipe, a socket 2 whose diameter is large is integratedlyformed at one end of the synthetic resin pipe 1, and a spiral recessed groove 21 which is thread-engaged with the protrusion 11 is fanned at the inner peripheral surface of the socket 2. In the inner peripheral surface of the socket, 2, a heating wire 3 is buried spirally, and both ends of the heating wire 3 are connected with pins 31 inside a connector 22 which is protrudingly-provided on the outer surface of the socket 2 at regular intervals from each other in the axial direction. In jointing two synthetic resin pipes 1, 1 with each other, adjacent pipes 1, 1 are connected with each other by spirally-engaging the recessed groove 21 with the protrusion 11, and a power terminal is connected with respective pins 31. By feeding electric power to the heating wire to heat it, the inner peripheral surface of the socket 2 and the outer peripheral surface of the end part, of the pipe 1 are fused for fusion joining.

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 synthetic resin pipes easily and reliably.

[0002]

2. Description of the Related Art Conventionally, when connecting synthetic resin pipes to each other, a heating wire is spirally embedded in the inner peripheral surface of a receiving port provided at one end of one synthetic resin pipe, and the other is synthesized in the receiving port. It is practiced to insert an end portion of a resin and then energize a heating wire to fuse and bond the joint surfaces.

[0003]

However, in the case of this fusion bonding, when the heating wire is energized and the receiving port is softened, the contraction occurs, so that the pipe end portion inserted into the receiving port is pushed out. There was a chance to escape. Therefore, both synthetic resin pipes were fixed with clamps, and then fusion splicing was performed.However, not only is the fixing operation with this clamp time-consuming, but both synthetic resin pipes must be securely fixed. Otherwise, the pipe end might escape from the receiving port until the melted surface was cooled, and a strong fusion bond could not be obtained.

The present invention has been made to solve the above problems and provides an electric fusion-bonding joint capable of easily and reliably connecting synthetic resin pipes.

[0005]

DISCLOSURE OF THE INVENTION The present invention is an electric fusion joint in which a heating wire is embedded spirally at a predetermined interval in the inner peripheral surface of a synthetic resin pipe or a joint of the joint, and the inner peripheral surface of the receptacle. And an outer peripheral surface of an end portion of the synthetic resin pipe fitted into the receiving opening, and a groove and a protrusion that are screwed with each other are provided, and the end portion of the synthetic resin pipe is screwed into the receiving opening before heating wire. It is characterized in that it is energized to perform fusion bonding.

[0006]

Since the inner peripheral surface of the receiving port and the outer peripheral surface of the end portion of the synthetic resin pipe are provided with the recessed ridges and the protrusions which are screwed into each other, the end portion of the synthetic resin pipe is screwed into the receiving port. When the heating wire is energized, the inner peripheral surface of the receiving port and the outer peripheral surface of the pipe end portion are melted and fusion bonded.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 is a half sectional view showing an embodiment of the present invention, FIG. 2 is a half sectional view showing a connection state of the synthetic resin pipe shown in FIG. 1, and FIG. 3 is a sectional view showing another embodiment of the present invention. Yes, 1 in the figure
Is a synthetic resin pipe such as polyethylene or polybutene, and 1a is a pipe joint made of the same kind of synthetic resin as the synthetic resin pipe 1.

First, the embodiment shown in FIGS. 1 and 2 will be described. Spiral protrusions 11 are provided on the outer peripheral surface of the synthetic resin pipe 1 at predetermined intervals in the pipe axial direction. An expanded receiving port 2 is provided at one end of the synthetic resin pipe 1, and a spiral groove 21 that is screwed into the protrusion 11 is provided on the inner peripheral surface of the receiving port 2. There is. Further, the heating wire 3 is embedded in a spiral shape at a predetermined interval on the inner peripheral surface of the receptacle 2, and both ends thereof are connected to the pins 31 of the connector 22 projecting on the outer surface of the receptacle 2. The heating wire 3 can be embedded along the spiral groove 21 if necessary.

When using this synthetic resin pipe 1 to make a pipe connection, the end portion of the other synthetic resin pipe 1 is screwed into the receiving port 2 of the one synthetic resin pipe 1, and the groove 21 and the protrusion 11 are screwed. To combine. Therefore, the connector 22 protruding from the outer surface of the receptacle 2
Connect the power terminal to the pin 31 (not shown) of the heating wire 3
When a current is applied to generate heat, the inner peripheral surface of the receiving port 2 and the outer peripheral surface of the pipe end portion are simultaneously melted and fusion-bonded. At the time of this fusion bonding, the receiving opening 2 is softened and contracts, and the concave groove 21 of the receiving opening 2 and the protrusion 11 of the pipe end are pressed against each other, so that a strong fusion bonding is obtained.

In the embodiment shown in FIG. 3, a flexible synthetic resin pipe 1 can be connected via a pipe joint 1a. That is, the tube wall of the synthetic resin tube 1 has a substantially uniform wall thickness, and flexibility is imparted by the protrusion 11 having an arcuate cross section provided on the outer peripheral surface of the tube. On the other hand, receiving ends 2 are provided at both ends of the pipe joint 1a, and the inner peripheral surface of the receiving port 2 is screwed with a spiral protrusion 11 provided on the outer peripheral surface of the synthetic resin pipe 1. A concave groove 21 is provided. Further, as in the above-described embodiment, the heating wire 3 is provided on the inner peripheral surface of the receiving port 2.
Are embedded in a spiral shape with a predetermined interval, and both ends of the pin 31 of the connector 22 projecting from the outer surface of the receptacle 2.
Connected with.

In this embodiment, when the synthetic resin pipes 1 are screwed onto both ends of the pipe joint 1a and then the heating wire 3 is energized, the inner peripheral surface of each receptacle 2 and the end of the synthetic resin pipe 1 are connected. The outer peripheral surface is melted and firmly fused and bonded.

It should be noted that the above-mentioned embodiments are merely examples of the present invention, and the present invention is not limited to this embodiment. For example, the protrusion 11 provided on the outer peripheral surface of the synthetic resin pipe 1 has a rectangular shape other than those shown in FIGS. 1, 2 and 3.
A triangular shape or any other suitable cross-sectional shape can be used. Also,
The protrusion 11 does not necessarily have to be continuously provided from one end to the other end of the synthetic resin pipe 1, but may be provided only at the pipe end, and in some cases, is only partially projected. May be. Further, contrary to the above-described embodiment, the protrusion 11 may be provided on the inner peripheral surface of the receiving port 2 and the spiral groove 21 may be provided on the outer peripheral surface of the end portion of the synthetic resin pipe 1.

[0013]

As described above in detail, according to the present invention, the inner peripheral surface of the receiving port and the outer peripheral surface of the end portion of the synthetic resin pipe are provided with the concave groove and the convex portion which are screwed into each other. The synthetic resin tube can be fusion-bonded easily and reliably simply by screwing the end portion of the synthetic resin tube and then energizing the heating wire.

[Brief description of drawings]

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

FIG. 2 is a half cross-sectional view showing a state in which the synthetic resin pipes shown in FIG. 1 are fusion-bonded to each other.

FIG. 3 is a sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 synthetic resin pipe 2 socket 3 heating wire 11 convex 21 concave groove 1a pipe joint

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazunori Umeda 2480 Sanchi, Hiratsuka, Kanagawa Mitsubishi Plastics Co., Ltd. Hiratsuka Factory

Claims (1)

[Claims] 1. An electrofusion joint in which a heating wire is embedded spirally at a predetermined interval on the inner peripheral surface of a synthetic resin pipe or joint, and the synthetic resin is fitted into the inner peripheral surface of the socket and the receptacle. A recessed groove and a protrusion are provided on the outer peripheral surface of the end of the pipe to be screwed with each other, and the end of the synthetic resin pipe is screwed into the receiving port, and then a heating wire is energized for fusion bonding. Characteristic electric fusion splicing joint.