JPS598206B2 - Information on how to get the job done - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of forming a socket portion of a resin pipe.

Resin pipes such as glass fiber-reinforced resin pipes (FW pipes), which are formed by winding glass fiber impregnated with synthetic resin, are usually formed in a straight pipe shape, and it is difficult to form the socket part at the same time. There are various difficulties.

Therefore, a method is often adopted in which a socket is formed at one end of a tube that is previously formed into a straight tube shape so that the one end fits onto the outside and forms a socket. If the body and the socket were formed separately, there would be a problem with the bonding force at the bonding surfaces, and there was a risk of peeling at this portion. The purpose of the present invention is to propose a method for forming a socket portion that can eliminate such drawbacks, and one embodiment thereof will be described below based on the drawings.

First, the structure of the socket part of the resin pipe to which the method of the present invention is applied will be explained with reference to FIG. This socket part 1 is the end part 2a of the tube body 2.
One end portion 3a of the socket 3 is externally fitted and polymerized, and an elastic body 4 such as a rubber packing is interposed in this polymerized portion. According to the socket portion 1 having such a structure, the pipe body 2 is Even if the tube body 2 is deformed by earth pressure, the deformation is absorbed by the elastic body 4, and the peeling stress acting on the joint between the tube body 2 and the socket 3 can be minimized. However, in order to form this socket part 1, the rubber packing 4 is first fitted and bonded to the end part 2a of the tube body 2, and then glass fiber impregnated with resin is wound around the outer periphery to form the socket 3. In this case, the adhesive force between the tubular body 2 and the rubber packing 4 was the weakest, and there was a risk that separation would occur in this portion. Therefore, in the method of the present invention, as shown in FIG. 2, a hollow annular body 5 whose cross-sectional shape can be deformed is fitted onto the tube end 2a, and the outer diameter of the hollow annular body is expanded. After fitting the blocking pressure-receiving jig 6 to the outside, pressure fluid is sent into the hollow T of the hollow annular body to reduce the diameter of the tube end 2a, and then a rubber packing 4 is fitted and bonded, and then the tube is closed. After the socket-forming core bar 8 is brought into contact with the body end surface, the socket 3 is formed by winding resin-impregnated glass fiber around the rubber packing 4 and the outer peripheral surface of the core bar 8. To explain the details, the hollow annular body 5 is mainly made of a rubber tube with a built-in core so that the circumferential length of the cross-sectional shape does not change even if pressure fluid is supplied into the hollow T. It is preferable to use an elastic body that can be deformed only between and a circular shape, and the diameter of this hollow annular body 5 is
It is desirable to use a tube whose inner diameter is an appropriate amount smaller than the outer diameter of the tube 2 so that the cross-sectional shape becomes flat when it is fitted onto the tube end 2a. Further, as shown in the figure, a pressure receiving jig 6 fitted around the outer periphery of the hollow annular body has flanges on both sides so as to surround the hollow annular body 5 from three directions in its cross-sectional shape. It is desirable that the deformation of the hollow annular body 5 when supplied is directed exclusively toward the inner circumferential side, but of course, if the hollow annular body 5 has a cross-sectional shape whose circumference does not extend unnecessarily, the flange It is also possible to use one without. In this way, the hollow annular body 5 is fitted onto the tube end 2a, and the pressure receiving jig 6 is fitted onto the outer periphery of the hollow annular body 5.
When pressure fluid is supplied inside, the hollow annular body 5 is deformed from a flat cross section to a circular shape, and as a result of this deformation, the outer diameter of the hollow annular body 5 is reduced by the inner diameter because it is held down by the pressure receiving jig 6. The diameter of the tubular body end portion 2a is elastically reduced. Note that this diameter reduction amount is Z of the pipe diameter. Approximately O-1/3000 is appropriate. Next, adhesive is applied to the outer periphery of the end of the tube and a rubber seal 4 is fitted onto the outside. If they are bonded, watertightness will be improved due to the tensile force between the adhesive and the rubber packing 4. Thereafter, the socket 3 of a predetermined thickness is formed as described above, and if a thermosetting resin and adhesive are used, the core bar 8 is heated by an appropriate means. In addition, the tube end 2a, the rubber packing 4, and the rubber packing 4
In order to improve the adhesion between the tube body end 2a and the socket 3,
Polish the outer surface with a grinder, etc., or use a rubber gasket 4.
It is desirable to treat the inner and outer peripheral surfaces with hydrochloric acid or to affix rubber with good adhesive properties. When the socket 3 hardens, the core bar 7 is pulled out, the supply of pressure fluid into the hollow 7 of the hollow annular body 5 is stopped, and the hollow annular body 5 and the pressure receiving jig 6 are removed. Then, the tube end 2a, which had been reduced in diameter, attempts to elastically restore its original shape, and due to the diameter expansion biasing force, the tube end 2a is press-fitted into the socket 3 via the rubber packing 4, and the adhesive force of the adhesive is increased. Together with this, the two are firmly connected. Incidentally, in the above embodiment, a case was described in which the rubber packing 4 was interposed between the tube end 2a and the socket 3, but the method of the present invention does not interpose the rubber packing 4 and the outer circumferential surface of the tube end 2a is It can also be applied directly to the case where the socket 3 is formed directly in the socket.

As is clear from the description of the above embodiments, according to the method of the present invention, the socket is formed with the end of the tube where the socket is to be formed reduced in diameter. The force causes the end of the tube to be press-fitted into the socket, and the two are firmly joined, eliminating the risk of separation at this joint.

In addition, in the method of the present invention, pressure fluid is sent into a hollow annular body whose outer periphery is held down by a pressure-receiving jig to reduce the diameter of the end of the tube, so it is possible to tighten with a uniform force over the entire circumference, and the device and operation are easy. It is extremely simple and has many effects.

[Brief explanation of drawings]

The drawings show an embodiment of the method of the present invention; FIG. 1 is a longitudinal cross-sectional view showing the structure of a socket to be formed, and FIG. 2 is a longitudinal cross-sectional view showing the state in which the method of the present invention is implemented. 1...Socket part, 2...Pipe body, 2a...
...Tube end, 3...Socket, 4...
...Rubber packing, 5...Hollow annular body, 6.
...Pressure jig, 7...Hollow, 8...
... Core metal.

Claims (1)

[Claims] 1. A hollow annular body whose cross-sectional shape can be deformed is fitted onto the end of the tube where the socket is to be formed, and a pressure receiving jig is fitted around the outer periphery of the hollow annular body to prevent the outer diameter from expanding. After that, the diameter of the tube end is reduced by sending pressure fluid into the hollow of the hollow annular body, and then, after a socket-forming core metal is brought into contact with the tube end surface, the tube end is 1. A method for forming a socket part of a resin pipe, the method comprising forming a socket on the outer circumferential surface of a socket part and a core metal.