JP2811297B2 - Connection method between large diameter synthetic resin pipe and metal pipe - 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 for connecting a large-diameter synthetic resin pipe and a metal pipe mainly used for water and sewage pipes. The term “metal pipe” as used herein generally refers to simple pipe-shaped metal pipes and elbow pipes, as well as various equipment used in pipe joints and piping systems, for example, tubular connection ports such as valves and meters.

[0002]

2. Description of the Related Art In general, synthetic resin pipes for water and sewage systems which have a large diameter are those having a diameter of 75 mm or more, and large ones are sewage pipes having a diameter of 2000 mm or more. Such a large-diameter synthetic resin pipe has a large diameter, so that its weight and volume are increased, and the eccentricity due to molding distortion is also increased. Therefore, when a metal pipe is inserted into the socket of the synthetic resin pipe at the work site and connected, it is very difficult to insert the pipe unless a large fitting difference (fitting clearance) is secured. Mismatch is a problem in terms of fitting strength and sealing degree.

[0003]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a connection method which can easily connect a large-diameter synthetic resin pipe and a metal pipe and can reliably maintain the connection strength and the degree of sealing. The main purpose is to

[0004]

In order to achieve the above object, the present invention takes the following technical measures. That is, in the connection method of the present invention, after inserting the metal pipe into the receptacle formed at one end of the synthetic resin pipe, halving from the outer peripheral face of the receptacle, heat is applied by the lower press mold. The metal tube insertion portion is crimped while being pressed, and at least a part of the crimped portion is wound and covered with a thin metal plate.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below based on an embodiment shown in the drawings. The large-diameter synthetic resin tube 1 shown in FIGS. 1 to 3 has a slightly larger diameter at one end and a receiving port 3 for receiving a metal tube 2 to be connected to the large-diameter portion. The large-diameter pipe according to the present invention is a water pipe mainly used for water supply and sewerage, and has a diameter of 75 mm to 2 mm.
000 mm or more. Further, in the embodiment, as a metal tube to be connected, a cylindrical connection port 5 having a spiral or annular protrusion 5a on the outer peripheral surface and having a packing 5b at the tip and a base end of the connection port 5 are formed. A metal flange tube comprising a large diameter flange 6 is shown.

According to the present invention, after the connection port 5 of the metal pipe is inserted into the receiving port 3 formed at one end of the synthetic resin pipe 1, the metal pipe insertion portion is vertically pressed from the outer peripheral surface of the receiving port. 7,
Crimping with 8. The press dies 7 and 8 have a form in which a cylinder is halved, and a heater 9 is mounted inside the press dies 7 and 8 so that a synthetic resin tube can be heated to a deformable temperature by a temperature controller (not shown). And mold 7,
The upper and lower dies 7 and 8 are pressed from the outer peripheral surface of the receiving port via a hydraulic cylinder or the like while applying a predetermined heat to 8, and the metal tube and the receiving port are pressure-bonded. Thereby, even if a loose fitting difference is provided between the metal resin pipe and the socket 3 of the synthetic resin pipe, the clearance between them is filled by the heat compression bonding to ensure a high fitting strength and a high degree of sealing. be able to.

[0007] Next, as shown in FIG.
At least a part of the crimped portion is wound around a thin metal tube 10, for example, a ring made of stainless steel having a thickness of about 3 mm on the outer peripheral surface to further strengthen the connection between the synthetic resin tube and the metal tube. I do.

Incidentally, the coating with the metal tube 10 is not limited to the above-mentioned means. For example, by drawing with a hydraulic roll, as shown in FIG. 3, the synthetic resin tube 1 can be covered with a thin stainless steel tube 10 having a thickness of about 1 mm from a large diameter portion to a small diameter portion.

The metal pipe 2 to be connected in the present invention is not limited to the above-mentioned flange pipe, and may be a pipe joint such as a one-sided joint pipe or a two-sided joint pipe, or various devices used in a piping system, such as valves and meters. Includes a tubular connection or a simple straight or elbow. In addition to the provision of the tubular projection as shown in the above embodiment, the connection port of the metal tube may be processed with an external screw or an internal screw, or may not be formed with a projection or a screw.

FIGS. 4 to 6 show the large-diameter synthetic resin tube 1 described above.
First, as shown in FIG. 4, a synthetic resin pipe material 1a formed in advance by extrusion molding means is cut into a predetermined length, and the cut pipe material 1a is cut as shown in FIG. Is softened to a plastically deformable state by immersing it in, for example, glycerin oil at 140 to 180 degrees Celsius, the pipe material 1a is set in the cavity 12 of the split mold 11, and the split mold 11 is tightened and fixed. The openings at both ends of the material 1a are sealed with plugs 13 and 13, and a pressure fluid such as heated air or oil is injected from an injection port 14 opened to one of the plugs 13, and the pipe material is sealed as shown in FIG. It is expanded toward the inner surface of the split mold cavity to expand the diameter to a predetermined size. After cooling the molded product taken out of the split mold 11, FIG.
As shown in (1), unnecessary portions at both ends are cut along a cutting line X to form a synthetic resin tube 1 having a receiving port 3 having a predetermined shape.

FIGS. 7 and 8 show a second means for producing the synthetic resin pipe 1. First, in the same manner as the first means, a synthetic resin pipe material 1a preformed by extrusion molding means. Is cut into a predetermined length, and the cut pipe material 1a is immersed in glycerin oil at 140 to 180 degrees Celsius to soften it to a state where it can be plastically deformed. Next, a cylindrical inflatable member 15 having a form to be formed on the outer peripheral surface is inserted into the softened pipe material 1a.

The expansion member 15 is divided into a plurality of parts in the radial direction so as to be expandable and contractable in the radial direction, and is slidably mounted around a plunger 18 reciprocated by a pressure cylinder 16. The distal ends of the conical wedge members 17a and 17b held by the plunger 18 are inserted into both ends of the shaft hole of the expansion member 11. One wedge member 17a is fixed to the tip of the plunger 18, and the other wedge member 17b is
8 is loosely fitted in the middle. With such a configuration, the inflating member 11 is inserted into the pipe member 1a as shown in FIG.
By operating the cylinder 16 to move the plunger 18 toward the cylinder, the expansion member 11 is radially expanded by the wedge members 17a and 17b, and the pipe member 1a is expanded to a predetermined size.

In this case, since the expansion member 11 is divided into a plurality of parts in the radial direction, when the expansion member expands, a gap is formed along the axial direction between the split dies, and the resin intrudes into this gap to protrude. Since an article occurs, a means for preventing this is necessary. As a means for this, for example, the expansion member 11 that has once been expanded is reduced, slightly rotated, and then expanded again, thereby preventing the occurrence of the ridge.

In the above-mentioned means for producing a synthetic resin pipe, a synthetic resin pipe material formed in advance by extrusion molding is cut into a predetermined length, and the cut pipe material is subjected to a secondary processing to a predetermined length. Since the large-diameter receiving port of the synthetic resin pipe is formed by expanding the diameter to the size of the above, there is no need for a large and expensive injection molding apparatus for individually molding the large-diameter pipe. Accordingly, equipment costs and product costs can be reduced.

In each of the above embodiments, the synthetic resin tube 1 is used.
Although the example in which the receiving port 3 for inserting the tube is provided only at one end of the above is shown, the receiving ports 3 may be provided at both ends.
In addition, it goes without saying that the synthetic resin pipe may be a synthetic resin pipe joint.

The synthetic resin pipe 1 is formed by cutting a synthetic resin pipe material formed in advance by extrusion molding means into a predetermined length, and cutting the cut pipe material into a metal pipe 2 by cutting means.
You may make it process the inner surface of the receiving port which accepts.

The embodiments of the present invention have been described above.
The present invention is not limited to these examples, and it is possible to provide the constituent elements thereof, and achieve the object of the present invention, and appropriately modify and implement within the scope of the following effects. Of course.

[0018]

Since the present invention is constructed as described above, even if a loose fitting difference is provided between the socket of the synthetic resin tube and the metal tube, the metal tube can be heated and pressed together. High clearance strength and tightness can be ensured by filling the clearance, and at least a part of the crimped portion is wound and covered with a thin metal plate on the outer peripheral surface of the synthetic resin pipe, so that the synthetic resin pipe and The connection of the metal tubes can be further strengthened.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a manufacturing method of the present invention.

FIG. 2 is a perspective view of a connection structure obtained by the manufacturing method of the present invention.

FIG. 3 is a perspective view showing another example of the connection structure obtained by the manufacturing method of the present invention.

FIG. 4 is a perspective view showing a first step of means for producing a synthetic resin tube in the present invention.

FIG. 5 is a sectional view showing a second step of the above-mentioned manufacturing means.

FIG. 6 is a sectional view showing a third step of the manufacturing means.

FIG. 7 is a perspective view showing an example of another means for producing a synthetic resin pipe according to the present invention.

FIG. 8 is a sectional view showing a second step of the above-mentioned manufacturing means.

[Explanation of symbols]

 Reference Signs List 1 synthetic resin pipe 1a pipe material 2 metal pipe 3 socket

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-109316 (JP, A) JP-A-7-332184 (JP, A) JP-A-7-16932 (JP, A) JP-A-4- 145295 (JP, A) JP-A-64-71736 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B29C 65/64 F16L 47/02 B29L 23:00

Claims (1)

(57) [Claims] After inserting a metal tube into a socket formed at one end of a synthetic resin tube, the metal tube is halved from the outer peripheral surface of the socket,
While applying heat with a lower press mold, crimp the metal tube insertion part,
A method for connecting a large-diameter synthetic resin tube and a metal tube, wherein at least a part of the crimped portion is wound and covered with a thin metal plate.