JP3088603B2 - Manufacturing method of pipe with inlet - Google Patents

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 pipe with a receiving port, and more particularly to a method of manufacturing a pipe with a receiving port having a port such as a rubber ring port, an adhesive port or an electric fusion port.

[0002]

2. Description of the Related Art An example of a method for manufacturing such a pipe with a port is disclosed in PCT / JP92 / 01733. According to this conventional technology, (a) a pipe and a heating element unit are attached to an inner mold, (b) an outer mold is connected to an inner mold to form a cavity, and (c) a moldable material is injected into the cavity. A pipe having a receiving port provided with a heating element unit on an inner surface thereof is manufactured.

[0003]

In the prior art, a gap is formed between the pipe mounted on the inner mold and the inner mold or the outer mold, and the moldable material injected into the cavity may leak from the gap. was there. There is also a problem that the jointability between the injection-molded port and the pipe body is poor.

SUMMARY OF THE INVENTION Accordingly, it is a primary object of the present invention to provide a method for manufacturing a pipe with a socket, which can prevent the leakage of the moldable material and can improve the joining property between the pipe body and the socket.

[0005]

According to the present invention, (a) a pipe is attached to an inner mold, (b) an outer mold is joined to an inner mold to form a cavity, and (c) hot air is sent into the cavity. (D) close the hot air path,
(e) A method for producing a pipe with a port, wherein a moldable material melted into a cavity is injected to form a port at an end of the pipe.

[0006]

When the end of the pipe is heated to near the melting point by sending hot air into the cavity, the end of the pipe is thermally expanded, and the inner mold and the outer mold are brought into close contact with each other. Therefore, the gap between the pipe and the inner mold or the outer mold is completely sealed, and leakage of the moldable material injected into the cavity is prevented.
Further, by heating the end of the pipe to near the melting point, the fusion between the end of the pipe and the moldable material is improved,
The joining property between the pipe body and the socket is improved.

[0007]

According to the present invention, leakage of the moldable material injected into the cavity can be prevented, and the joining property between the pipe and the receiving port can be improved. The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A pipe with a port 10 manufactured by the manufacturing method of this embodiment shown in FIG. 1 includes a pipe body 12 made of a synthetic resin such as polyethylene or polybutene. An enlarged diameter receiving port 14 is formed at an end of the pipe main body 12, and a net-shaped magnetic alloy heater 16 as shown in FIG. 2 is provided at or near the inner peripheral surface of the receiving port 14. This pipe 10 with a port is used to insert another pipe into the port 14 and apply a current to the magnetic alloy heater 16 by using electromagnetic induction to fuse and join the two pipes.

Such a pipe with a receiving port 10 is manufactured by using an inner mold 18 and an outer mold 20 as shown in FIG. The inner die 18 includes a substantially cylindrical pipe mounting portion 22.
The distal end of the pipe mounting portion 22 is tapered to facilitate mounting of the pipe 12 ', and the inner portion of the pipe mounting portion 22 is tapered so that the end of the pipe 12' can be enlarged. The diameter is expanded. The heater mounting portion 26 is formed by further expanding the diameter from a predetermined distance from the tapered enlarged portion 24 to form the heater mounting portion 2.
6 is further enlarged from the coupling surface 2 to be coupled with the outer mold 20.
8 are formed.

The outer mold 20 includes a first mold 20a and a second mold 20b which open and close in a vertical direction in FIG.
0a and the second die 20b have a pressing surface 30 for pressing the outer surface of the pipe 12 'and a cavity 32 in cooperation with the inner die 18.
Cavity forming surface 34 and inner mold 1 forming (FIG. 4)
A coupling surface 36 that couples with the coupling surface 28 of FIG. 8 is formed. The hot air outlet 3 is provided on the cavity forming surface 34 of the first mold 20a.
8 and a hot air discharge port 40 are formed. Inside the first mold 20a, a hot air path 42 communicating with the hot air outlet 38, a hot air path 44 communicating with the hot air discharge port 40, and a stopper pin 46 are provided.
Is formed, and a hole 52 through which the stopper pin 50 is inserted is formed. Stopper pins 46 and 50
3 by hydraulic cylinders 54 and 56 respectively.
, The hot air outlet 38 and the hot air outlet 40 are opened and closed. A hot air generator 57 is connected to the hot air path 42. on the other hand,
A gate 60 for injecting a moldable material 58 (FIG. 5) such as polyethylene or polybutene into the cavity 32 (FIG. 4) is formed in the second mold 20b.

In manufacturing the pipe 10 with a receiving port (FIG. 1), first, as shown in FIG. 3, the magnetic alloy heater 16 (FIG. 2) is mounted on the heater mounting portion 26 of the inner die 18, and A pipe 12 'whose tip is preheated to a mounting portion 22.
(In this example, a straight pipe). At this time, the tip of the pipe 12 ′ is slightly enlarged by the tapered portion 24 of the inner die 18. Then, as shown in FIG.
That is, the first molds 20 a and 20 b are closed to form the cavity 32, and hot air is blown into the cavity 32 from the hot air generator 57 connected to the hot air path 42. At this time, the hot air outlet 38 and the hot air outlet 40 are both open, so that the hot air sent from the hot air outlet 38 to the cavity 32 is discharged from the hot air outlet 40 through the hot air path 44.

When the tip of the pipe 12 'is heated to near the melting point by blowing hot air into the cavity 32, the hot air outlet 38 and the hot air outlet 40 are provided by stopper pins 46 and 50 as shown in FIG. Is closed, and the moldable material 58 is injected into the cavity 32 from an injection molding machine (not shown) connected to the gate 60. Then, the tip of the pipe 12 'and the moldable material 58 are cooled. After cooling, the outer mold 20, that is, the first mold 20 a and the second mold 20 b are opened, and the pipe with a port 10 is removed from the inner mold 18, as shown in FIG. 6.

According to this embodiment, the pipe 12 'and the inner mold 18 are caused by the thermal expansion of the pipe 12' heated by hot air.
And the gap with the outer mold 20 can be reliably sealed. Therefore, it is possible to prevent the moldable material 58 injected into the cavity 32 from leaking. Also, pipe 1
Since the tip of 2 ′ is heated to near the melting point, the fusion between the pipe 12 ′ and the moldable material 58 (FIG. 5) can be improved, and the tip of the pipe 12 ′ is tapered 24 (FIG. 5). Combined with the expansion of the diameter in 3), the joining property between the pipe main body 12 and the receiving port 14 (FIG. 1) can be improved.

In the above-described embodiment, the net-like magnetic alloy heater 16 (FIG. 2) is used, but instead, a magnetic alloy heater formed as a punching metal as shown in FIG. Alternatively, a magnetic alloy heater 68 in which a magnetic alloy powder 66 is mixed with a synthetic resin 64 as shown in FIG. 8 may be used. Further, in the above embodiment, the pipe 12 '(straight pipe) is used, but instead, a cheese, an elbow, or the like may be used. In this case, for example, a joint or a pipe with a receiving port as shown in FIG. 9 or FIG. 10 can be obtained.

Further, in addition to the pipe 10 having the electro-fusion port as in the above-described embodiment, the present invention provides, for example, a pipe 72 having an adhesive port 70 as shown in FIG. 11 and a pipe 72 as shown in FIG. The present invention can be applied to a case where a pipe 76 having a rubber ring receiving port 74 is manufactured. That is, the pipe 72
When manufacturing (FIG. 11), the step of mounting the magnetic alloy heater on the heater mounting section 26 (FIG. 3) is omitted, and when manufacturing the pipe 76 (FIG. 12), the rubber ring 78 is mounted. Cavity 3 so as to form a groove 80 therein.
2 (FIG. 4) is deformed.

[Brief description of the drawings]

FIG. 1 is an illustrative view showing a pipe with a mouth;

FIG. 2 is an illustrative view showing a magnetic alloy heater used in the pipe with a port shown in FIG. 1;

FIG. 3 is an illustrative view showing a state where a magnetic alloy heater and a pipe are mounted on an inner die;

FIG. 4 is an illustrative view showing a state where a cavity is formed by closing an outer mold;

FIG. 5 is an illustrative view showing a state where a moldable material is injected into a cavity;

FIG. 6 is an illustrative view showing a state where an outer mold is opened;

FIG. 7 is an illustrative view showing a modified example of the magnetic alloy heater;

FIG. 8 is an illustrative view showing a modified example of the magnetic alloy heater;

FIG. 9 is an illustrative view showing a state where cheese is used as a pipe;

FIG. 10 is an illustrative view showing a state where an elbow is used as a pipe;

FIG. 11 is an illustrative view showing another pipe with a port to which the present invention is applied;

FIG. 12 is an illustrative view showing another pipe with a port to which the present invention is applied;

[Explanation of symbols]

 10, 72, 76 ... pipe with receiving port 12 ... pipe body 12 '... pipe 14, 70, 74 ... receiving port 16, 62, 68 ... magnetic alloy heater 18 ... inner mold 20 ... outer mold 32 ... cavity 38 ... hot air blowing Outlet 40 Hot air outlets 42,44 Hot air path 46,50 Stopper pins 54,56 Hydraulic cylinder 57 Hot air generator

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI F16L 47/02 F16L 47/02 // B29L 23:00 (72) Inventor Taku Taku 64 Ishizukitamachi, Sakai-shi, Osaka (56) References JP-A-4-226314 (JP, A) JP-A-6-47767 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 45 / 00-45/84 F16L 21/00 F16L 47/02

Claims (2)

(57) [Claims] (A) attaching a pipe to an inner mold; (b) connecting an outer mold to the inner mold to form a cavity; and (c) sending hot air into the cavity to form an end of the pipe. (D) closing the path of the hot air, (e) injecting the meltable moldable material into the cavity to form a receiving port at the end of the pipe, with a receiving port. Pipe manufacturing method. 2. The manufacturing method for a pipe with a spout according to claim 1, wherein a magnetic alloy heater is mounted on the inner mold before the step (a), and an electrofusion spout incorporating the magnetic alloy heater is formed. Method.