JP2000081189A - Manufacture of thermoplastic resin tubular member with socket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a fear of an electric heat generating body being buckled when the electric heat generating body is inserted into one end of a thermoplastic resin tubular member and to reduce a cost. SOLUTION: In a manufacturing method of a thermoplastic resin tubular member with a socket wherein one end is provided with an expansion socket and an electric heat generating body is arranged in the socket, one end of a thermoplastic resin tubular member 1 is heated, an expansion mold is inserted in the internal part of one end of the thermoplastic resin tubular member 1 and a socket 11 is formed at one end of the thermoplastic resin tubular member 1. Thereafter, the expansion mold is pulled out from the socket 11, a core provided with the electric heat generating body is inserted in the socket, and an outer mold is matched in a closing state with the periphery of the socket.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a thermoplastic resin tubular member having a receiving end provided with an enlarged opening at one end and an electric heating element in the receiving end.

[0002]

2. Description of the Related Art Conventionally, as described in, for example, Japanese Patent No. 2709363, a thermoplastic resin pipe with a receiving port provided with an enlarged receiving port at one end and an electric heating element in the receiving port. Manufacturing methods are known.

In the method of manufacturing a thermoplastic resin pipe with a socket described in the above-mentioned Japanese Patent No. 2,709,363, as shown in FIG. 11, one end of a thermoplastic resin pipe (a) is heated, and the thermoplastic resin pipe (a) is heated. Insert a core mold (c) with a heating element unit (b) including an electric heating element inside one end of the pipe (b) in the direction of the arrow to expand one end of the thermoplastic resin pipe (b) and expand the diameter. The heating element unit (b) is incorporated into one end of the diametered thermoplastic resin pipe (a), and the core mold (c) is pulled out.

[0004]

However, in the method of manufacturing a thermoplastic resin tube with a port described in Japanese Patent No. 2709363, the following inconveniences are caused.

That is, in the method of manufacturing a thermoplastic resin pipe with a socket described in the above-mentioned Japanese Patent No. 2,709,363, one end of the thermoplastic resin pipe (a) is heated, and the thermoplastic resin pipe (a) is heated. Insert a core mold (c) with a heating element unit (b) inside one end to expand one end of the thermoplastic resin tube (b) and into one end of the expanded thermoplastic resin tube (b). Since it incorporates a heating element unit (b),
When the core mold (c) is inserted into one end of the thermoplastic resin pipe (a), as shown in FIG. 12, the tip of the heating element unit (b) is attached to the end face of one end of the thermoplastic resin pipe (a). The vicinity (d) of the end of the heating element unit (b) is likely to buckle upon impact.

Therefore, in the method of manufacturing a thermoplastic resin tube with a socket described in Japanese Patent No. 2709363, the thickness must be increased so that the heating element unit (b) does not buckle.

For this purpose, the above-mentioned Japanese Patent No. 2709363 is disclosed.
In the method for manufacturing a thermoplastic resin tube with a port described in Japanese Patent Application Laid-Open Publication No. H11-260, the heating element unit (b) has a large thickness as shown in FIG. (E) must be used.

That is, in the thick heating element unit (e) shown in FIG. 13, a thermoplastic resin layer (g) is provided around the heating element (f) by injection molding. Thus, the heating element unit (e) having a large thickness T
When the heat generating element (e) is used, it is difficult for the heat of the heating element (f) to be transmitted to the inner surface of the expanded part (h) of the thermoplastic resin pipe (a). In addition, there is a risk of water leaking without fusing with the inner surface of (2), and it is difficult to reduce the cost because an injection mold is used.

The present invention has been made in view of the above-mentioned problems in the conventional method of manufacturing a thermoplastic resin tubular member with a port, and an object thereof is to provide a conventional thermoplastic resin tube with a port. The problem with the manufacturing method of the present invention is that there is no danger that the electric heating element will buckle when the electric heating element is inserted into one end of the thermoplastic resin tubular member, and the cost can be reduced. An object of the present invention is to provide a method for manufacturing a plastic resin tubular member.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a method of manufacturing a thermoplastic resin tubular member having a socket according to the present invention is described.
A method of manufacturing a thermoplastic resin tubular member with a receiving port provided with a receiving port having an enlarged diameter at one end and an electric heating element in the receiving port,
After heating one end of the thermoplastic resin tubular member, inserting a diameter-expanding die inside one end of the thermoplastic resin tubular member to form a receiving port at one end of the thermoplastic resin tubular member, and then removing the diameter expanding die from the receiving port. Pull out, insert the core with the electric heating element into the receptacle,
The outer mold is closed around the receptacle.

In the present invention, as the thermoplastic resin which is the material of the thermoplastic resin tubular member, the thermoplastic resin which has conventionally been the material of the thermoplastic resin tubular member having a receiving port provided with an electric heating element in the receiving port is used as it is. Can be used,
Although not particularly limited, for example, polyethylene, polypropylene, polybutene and the like can be used.

In the present invention, the thermoplastic resin tubular member may be a thermoplastic resin tube, a straight pipe, a T-shaped pipe, an
A tubular or cross-shaped thermoplastic resin pipe joint may be used.

[Operation] In the method of manufacturing a thermoplastic resin tubular member having a socket according to the present invention, one end of the thermoplastic resin tubular member is heated, and a diameter expanding mold is inserted into one end of the thermoplastic resin tubular member. After forming the receiving port at one end of the thermoplastic resin tubular member, the enlarged diameter die is pulled out from the receiving port, and the core mold with the electric heating element is inserted into the receiving port. By inserting a large-diameter die having an outer diameter larger than the outer diameter of the core mold equipped with the electric heating element inside one end, a receptacle having an inner diameter larger than the outer diameter of the core mold fitted with the electric heating element is formed. Therefore, there is no fear that the electric heating element will buckle when the core mold with the electric heating element is inserted into the receptacle.

In the present invention, the core mold having the electric heating element mounted thereon is inserted into the receptacle having a larger inner diameter than the core mold having the electric heating element mounted thereon, and the outer mold is closed around the receptacle. Therefore, the inner surface of the receptacle can be brought into close contact with the electric heating element inserted in the core mold.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, as shown in FIG. 1, a thermoplastic resin tubular member has a length of 5 m and a diameter of 250 mm.
A high-density polyethylene pipe 1 is used, and the tip of the pipe 1 where the port is to be formed is heated by the heating device 2 to soften the tip of the pipe 1.

Next, as shown in FIG. 2, an expanding die 3 having an outer diameter D1 is inserted into the heat-softened distal end of the tube 1 as shown by an arrow a. A convex portion 31 for forming a terminal insertion port is provided on the surface of the enlarged diameter die 3. Further, a pin 32 for forming an indicator insertion hole is provided in a middle portion of the large-diameter die 3, and the pin 32 is provided at one end of the small rod 33.
An inclined surface 34 is provided at the other end of 3, and the small rod 33 is inserted so as to be able to move up and down in a vertical hole 35 formed in the large-diameter die 3. A slope 37 provided at one end of another small rod 36 is in contact with the slope 34 of the small rod 33 so that the other small rod 36 can reciprocate in a horizontal hole 38 formed in the large-diameter die 3. Has been inserted.

The pin 32 protrudes from the surface of the large-diameter die 3 by advancing another small rod 36 inside the lateral hole 38, and from the surface of the large-diameter die 3 by retracting the other small rod 36 inside the lateral hole 38. The protruding pin 32 is retracted into the vertical hole 35.

With the pin 32 retracted into the vertical hole 35, the expanded diameter mold 3 is inserted into the heat-softened tip of the tube 1 as shown by an arrow a, thereby heating and softening the tube 1 as shown in FIG. The diameter of the formed distal end portion is increased to form the receiving port 11, and the terminal insertion port 12 is formed at the distal end of the tube 1 by the terminal insertion port forming projection 31.

Next, the pin 32 is made to protrude from the surface of the large-diameter die 3 by advancing the other small rod 36 to form the indicator insertion hole 13 at the tip of the tube 1. The outer shape of the distal end of the tube 1 is formed by closing the split outer mold 4 from around the distal end of the tube 1. Next, the pin 32 is retracted into the vertical hole 35 by retreating the other small rod 36, and the enlarged die 3 is pulled out from the distal end port 11 of the tube 1.

Next, as shown in FIG. 4, the core mold 6 with the electric heating element 5 mounted thereon is inserted into the distal end port 11 of the tube 1 as shown by an arrow b. The outer diameter D2 of the core mold 6 to which the electric heating element 5 is mounted is slightly smaller than the outer diameter D1 of the enlarged diameter mold 3. The electric heating element 5 has a cylindrical shape in which a covered electric wire in which a heating wire made of a copper-nickel alloy is covered with high-density polyethylene is wound in a double coil shape. Reference numeral 51 denotes a terminal provided at an end of the electric heating element 5.

The outer surface of the receptacle 11 is formed by closing the outer mold 4 from the periphery of the receptacle 11 of the tube 1, and the inner surface of the receptacle 11 is brought into close contact with the electric heating element 5 inserted into the core mold 6. . After the receiving port 11 is cooled, the outer die 4 is split, and the core die 6 is pulled out of the receiving port 11 to form the receiving port 11 at the tip of the tube 1 as shown in FIG. The electric heating element 5 is attached, and the terminal 51 is inserted into the insertion port 12.

Next, in FIG.
The indicator 7 shown in an enlarged manner is inserted. The indicator 7 is provided with a base plate 72 at the lower end of the main body 71.
The ring 73 is placed on the.

When such an indicator 7 is inserted into the indicator insertion hole 13, the heating state of the electric heating element 5 can be known at the time of use, and another thermoplastic resin pipe inserted into the receiving port 11 can be used. Can be grasped.

As shown in the illustrated embodiment, in the method of the present invention, one end of the thermoplastic resin tube 1 is heated, and the expanded diameter mold 3 is inserted into one end of the thermoplastic resin tube 1 so that the thermoplastic resin tube 1 is inserted. After forming the receiving port 11 at one end of the pipe, the enlarged diameter mold 3 is pulled out from the receiving port 11 and the core die 6 equipped with the electric heating element 5 is inserted into the receiving port 11. The outer diameter D2 of the core die 6 having the electric heating element 5 mounted inside one end of the core die 1
By inserting the enlarged die 3 having an outer diameter D1 larger than that, the receptacle 11 having an inner diameter larger than the outer diameter D2 of the core die 6 to which the electric heating element 5 is mounted can be formed. When the mounted core die 6 is inserted into the receptacle 11, there is no fear that the electric heating element 5 will buckle as in the related art.

In the method of the present invention, the core mold 6 with the electric heating element 5 is inserted into the receiving port 11 having an inner diameter larger than the outer diameter D2 of the core mold 6 with the electric heating element 5 attached. Since the outer mold 4 is closed around the receptacle 11, the inner surface of the receptacle 11 and the electric heating element 5 inserted into the core mold 6 can be brought into close contact with each other.

Although the embodiment of the present invention has been described with reference to the drawings, the specific configuration of the present invention is not limited to the illustrated embodiment, and design changes within a scope not departing from the gist of the present invention. Are included in the present invention. For example, instead of forming the indicator insertion hole 13 by projecting the pin 32 from the enlarged diameter die 3 as in the illustrated embodiment, the indicator hole 11 may be formed and then drilled.

The tubular member with a socket manufactured by the method of the present invention is replaced with a tube 1 as in the illustrated embodiment.
As shown in FIG. 8, a T-shaped pipe 8 may be used, an elbow joint 81 may be used as shown in FIG. 9, and a short pipe joint 82 may be used as shown in FIG. It may be.

[0028]

According to the method of manufacturing a thermoplastic resin pipe with a receiving port of the present invention, an enlarged diameter mold having an outer diameter larger than the outer diameter of a core mold having an electric heating element mounted inside one end of the thermoplastic resin pipe is provided. By inserting the electric heating element, it is possible to form a receptacle with an inner diameter larger than the outer diameter of the core mold with the electric heating element, and when inserting the core mold with the electric heating element into the receptacle, the electric heating element Since there is no risk of buckling, there is no need to use a heating element unit or the like having a large thickness as in the related art, and it is not necessary to use an injection molding die, so that cost can be reduced.

In the present invention, since the inner surface of the receptacle can be brought into close contact with the electric heating element inserted in the core mold, there is no danger of water leakage.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view showing a mode in which one end of a thermoplastic resin tube is heated by the method of the present invention.

FIG. 2 is a partially cutaway front view showing an embodiment in which an enlarged-diameter die is inserted into one end of a pipe according to the method of the present invention.

FIG. 3 is a cross-sectional view showing a state in which an enlarged-diameter mold is inserted into one end of a pipe by the method of the present invention and an outer mold is closed.

FIG. 4 is a cross-sectional view showing an embodiment in which a core having an electric heating element mounted therein is inserted into one end of a tube according to the method of the present invention.

FIG. 5 is a cross-sectional view showing a state in which a core mold having an electric heating element mounted therein is inserted into one end of a tube according to the method of the present invention, and the outer mold is closed.

FIG. 6 is a partially cutaway front view showing a tubular member with a socket manufactured by the method of the present invention.

FIG. 7 is a partially cutaway front view showing an indicator.

FIG. 8 is a sectional view of a T-shaped pipe joint that can be manufactured by the method of the present invention.

FIG. 9 is a cross-sectional view of an elbow fitting manufactured by the method of the present invention.

FIG. 10 is a sectional view of a short pipe joint that can be manufactured by the method of the present invention.

FIG. 11 is a partially cutaway front view showing a mode of manufacturing a tubular member with a port by a conventional method.

FIG. 12 is a partially cutaway front view showing an embodiment of manufacturing the tubular member with a port by a conventional method, showing the next step of the embodiment shown in FIG. 11;

FIG. 13 is a sectional view showing a main part of a tubular member with a socket manufactured by a conventional method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thermoplastic resin pipe (tubular member) 11 Receptacle 2 Heating device 3 Large diameter type 4 Outer type 5 Electric heating element 6 Core type 7 Indicator

Claims (1)

[Claims] 1. A method of manufacturing a thermoplastic resin tubular member having a receiving port having an enlarged receiving port at one end and an electric heating element in the receiving port, wherein one end of the thermoplastic resin tubular member is heated. ,
After inserting the enlarged diameter mold into one end of the thermoplastic resin tubular member to form a receiving port at one end of the thermoplastic resin tubular member, pull out the enlarged diameter mold from the receiving port, and remove the core mold fitted with an electric heating element. A method for manufacturing a thermoplastic resin tubular member with a port, wherein the tubular member is inserted into the port and the outer mold is closed around the port.