JPH03243229A - Formation of faucet part of composite tube - Google Patents

Abstract

PURPOSE:To prevent water from leaking from between a seal member and an inserting part by peeling the synthetic resin layer of an end part, exposing the inner peripheral surface of a metallic tube, sticking a seal member having a cylindrical tongue piece to the metallic tube and expanding the diameter of the end part of a composite tube. CONSTITUTION:First, synthetic resin 13 and an adhesive layer 12 of one end part to form a facet part of the composite tube 10 is peeled by a prescribed length in the direction of the shaft and the inner peripheral surface of the metallic tube 11 is exposed by a prescribed length. Then, the outer peripheral surface of the seal member 20 is coated with adhesive and the seal member 20 is fitted into the end part of the composite tube 10. Then, the end part of the composite tube 10 to which the seal member 20 is stuck is mounted on a bulging machine 30 to bulge the diameter. In this way, stress remains in the inner part of the seal member 20 fitted to the end part of the composite tube 10 and is energized so that the tip part of the tongue piece 22 is contracted in diameter, accordingly, the tongue piece is stuck strongly to the outer peripheral surface of the inserting part and the seal effect by the seal member 20 is improved remarkably.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for forming a socket at the end of a composite pipe whose inner peripheral surface is coated with a synthetic resin layer.

(Prior Art) For example, a composite pipe in which the inner peripheral surface of a metal pipe is coated with a synthetic resin layer is used as a drain pipe installed vertically in a building in a substantially vertical manner. When connecting such composite pipes, a method is usually adopted in which a socket is formed at the end of one composite pipe and a socket is inserted at the end of the other composite pipe. . The socket part formed at the end of the composite pipe is made by expanding the diameter of one end of the composite pipe in advance, and fitting a cylindrical seal member made of rubber, for example, into the expanded end. It is formed by bonding with an adhesive.

(Problem to be Solved by the Invention) In the socket formed by such a method, the insertion part is inserted into a sealing member that is fitted into the end of a composite pipe whose diameter has been expanded in advance, and the seal The inner circumferential surface of the member comes into close contact with the outer circumferential surface of the inserted receptacle, thereby sealing between the receptacle and the receptacle. Since the sealing effect of the sealing member is due to the elastic force of the sealing member itself, the adhesion with the outer circumferential surface of the end of the insertion port is insufficient, and a sufficient sealing effect is not exhibited. For this reason, a convex portion that protrudes inward is formed on the inner circumferential surface of a cylindrical seal member to improve the adhesion with the insertion opening. However, also in this case, the insertion part inserted into the seal member is
If the seal member is tilted at an angle of about 4 degrees or more with respect to the axis of the seal member, water may leak from between the inner circumferential surface of the seal member and the outer circumferential surface of the socket.

The present invention solves the above-mentioned conventional problems, and its purpose is to eliminate the risk of water leaking between the sealing member and the socket due to the sealing member coming into strong contact with the outer peripheral surface of the socket to be inserted. It is an object of the present invention to provide a method for forming a socket portion of a composite pipe.

(Means for Solving the Problems) The method for forming a socket part of a composite pipe of the present invention involves peeling off the synthetic resin layer at the end of the composite pipe in which the synthetic resin layer is adhered to the inner circumferential surface of the metal pipe, and A seal that includes a step of exposing a peripheral surface, and a cylindrical tongue piece that protrudes from one end of an elastic cylindrical seal main body with its diameter gradually decreasing inward to the innermost side of the seal main body. arranging the member on the exposed inner circumferential surface of the metal tube at the end of the composite tube so that the protruding direction of the tongue piece is on the inner side of the composite tube, and bonding the member to the metal tube; and sealing. The method includes the step of expanding the diameter of the end of the composite pipe to which the member is bonded together with the sealing member into a predetermined shape, thereby achieving the above object.

(Example) The present invention will be described below with reference to Examples.

As shown in FIG. 1, the method for manufacturing a composite pipe having a socket according to the present invention is such that a synthetic resin layer 13 made of polyvinyl chloride is formed on the inner peripheral surface of a metal pipe 11 made of steel, for example. This is carried out when forming a socket part into which the sealing member 20 is fitted at the end of the composite pipe 10 which is bonded with the adhesive layer 12 having such elasticity.

The seal member 20 is made of an elastic body such as urethane rubber, and includes a cylindrical seal body 21 and a seal body ll from one end of the seal body 11.
It has an annular tongue piece 22 that protrudes in the axial direction.

The cylindrical seal main body part 21 has a thin walled part 21 whose outer circumferential side is notched at the end on the half body side from the end where the tongue piece 22 is provided.
a, and an annular metal fan 23 made of, for example, stainless steel is concentrically buried in the thin wall portion 21a. A locking portion 21c that protrudes inward is provided at the tip of the thin portion 21a over the entire circumference. Moreover, three annular protrusions 21b protruding inward are provided at the center of the inner circumferential surface of the seal body 21 over the entire circumference at appropriate intervals in the axial direction.

The tongue piece 22 that protrudes inward from one end of the seal body 21 becomes thinner as it approaches the tip side.
Its tip is sharply pointed.

A pressing portion 22a having a semicircular cross section and protruding toward the seal body 21 is provided on the circumferential surface of the tongue piece 22 facing the inner circumferential surface of the seal body 21 over the entire circumference.

The sealing member 20 having such a configuration is used when carrying out the method of the present invention.

In the method for forming a socket part of the present invention, first, a synthetic resin layer 1 at one end of the composite pipe IO where a socket part is to be formed.
3 and the adhesive layer 12 are peeled off over a predetermined length in the axial direction, and the inner peripheral surface of the metal tube 11 is exposed over a predetermined length. The length over which the synthetic resin layer 13 and the adhesive layer 12 are peeled off is equal to the length of the seal body 21 of the seal member 20 excluding the thin portion 21a.

In this state, an adhesive is applied to the outer peripheral surface of the sealing member 2o, and the sealing member 2o is fitted into the end of the composite pipe. In the sealing member 20, the protruding direction of the tongue piece 22 is
It is fitted into the end of the composite tube 10 so as to be on the innermost side of the composite tube 10, and the thin wall portion 21a of the seal body 21 is adhered to the synthetic resin layer 13 at the end of the composite tube 10. As a result, the outer circumferential surface of the sealing member 2o is bonded to the end of the composite tube 10 with the adhesive.

Next, the end of the composite pipe 1o to which the /-ru member 20 is adhered is attached to a bulge processing machine 3o, as shown in FIG. The bulge processing machine 3o enlarges the diameter of the end of the composite pipe 10 to which the sealing member 2° is adhered by bulging, and the end of the composite pipe 10 is located inside the composite pipe 10, which can be divided into two parts. It has an outer mold 31. The outer mold 31 has one end surface,
It has a through hole 31a that is approximately equal to the outer diameter of the composite tube 10, and the end of the composite tube 10 is inserted into the outer mold 31 through the through hole 31a. The inner peripheral surface of the outer mold 31 has a shape corresponding to the outer peripheral surface of the socket structure to be formed.

A rod 32 is disposed within the outer mold 31 so as to be movable in the axial direction along the axis of the composite tube 10 inserted into the outer mold 31 through the through hole 31a. One end of the rod 32 extends to the outside of the outer mold 31 from an end surface opposite to the end surface in which the through hole 31a of the outer mold 31 is formed, and the end is connected to a piston 33a in the hydraulic cylinder 33. has been done. When the piston 33a moves in the axial direction of the hydraulic cylinder 33, the rod 32 moves in the axial direction. A disk-shaped pressing member 34 having an outer diameter approximately equal to the inner diameter of the synthetic resin layer 13 in the composite tube 10 is attached to the other end of the rod 32 .

An elastic member 35 is slidably fitted into the rod 32 between the pressing member 34 and the inner surface of the outer mold 31 facing the pressing member 34 . The elastic member 35 is made of an elastic body such as urethane rubber, and when the opening and the door 32 are fully advanced from the hydraulic cylinder 33, the pressing member 34 does not press the elastic member 35, and the elastic member 35 is in a stretched state due to its own elastic force. In this state, the elastic member 35 has a cylindrical shape with an outer diameter slightly smaller than the inner diameter of the composite tube IO, and the tip of the tongue piece 22 of the seal member 20 is in contact with the outer peripheral surface of the elastic member 35. Then, when the rod 32 moves in the direction of retraction into the hydraulic cylinder 33, the elastic member 35 is compressed by the pressing member 34 and the inner surface of the composite pipe IO and expands in the radial direction.

With the bulge processing machine 30 having such a configuration, the composite pipe IO
When forming a socket at the end of the rod 32, first, the hydraulic cylinder 33 is driven to make the rod 32 extend beyond the hydraulic cylinder 33. Then, a lubricant is applied to the circumferential surface of the elastic member 35 in order to reduce the friction between the elastic member 35 and the synthetic resin layer 13.

As such a lubricant, commonly used lubricants such as lead stearate, detergents, oils, greases, rubber adhesives, etc. are used. In this state, the outer mold 31 is divided into two parts, and the elastic member 35 is inserted into the seal member 20 bonded to the end of the composite pipe 10. As a result, the tip of the elastic member 35 passes through the seal member 20 and is opposed to the inner circumferential surface of the composite tube 10 . Seal member 2
The zero tongue piece 22 is in close contact with the outer peripheral surface of the elastic member 35.

Thereafter, the divided outer molds 31 are integrated and fixed.

Fixation of the outer mold 31 is achieved by mechanical locking or pressing by a hydraulic cylinder. Only the end portion of the composite tube 10 is located within the integrated outer mold 31, and the other portion extends to the outside from the through hole 31a of the outer mold 31. Through hole 3
The inner diameter of 1a is slightly larger than the outer diameter of the composite tube 10, and the composite tube 10 is loosely fitted into the through hole 31a.

In this state, the hydraulic cylinder 33 is driven and the rod 3
2 into and out of the hydraulic cylinder 33.
Move it in the direction shown by arrow A in the figure. At the same time, composite pipe 10
Pressure is applied to the composite tube 10 so that it enters the outer mold 31. As a result, the pressing member 34 attached to the tip of the rod 32 moves toward the end surface of the composite tube 10 within the outer mold 31, and the elastic member 35 is compressed by the pressing member 34.

As a result, the elastic member 35 expands outward and presses the seal member 20 fitted to the end of the composite tube 10 in the radial direction.

Synthetic resin layer 1 on the outer peripheral surface of the elastic member 35 and the composite pipe 10
If a lubricant is provided between the elastic member 35 and the inner circumferential surface of the elastic member 35, the elastic member 35 is smoothly compressed, and the metal tube 11 and the seal member 20 expand in diameter together.

At this time, if pressure is applied to the composite pipe 10 so that the end face located inside the outer mold 31 is pressed against the inner surface of the outer mold 31, when the end of the composite pipe 10 is expanded in diameter, the metal Since the tube 10 moves inside the outer mold 31, there is no risk that the metal tube portion whose diameter is expanded will become thin, and the end surface will be pulled away from the inner surface of the outer mold 31, thereby increasing the length of the socket. There is no risk that the length will become shorter.

Thereafter, when the rod 32 is further moved into and out of the hydraulic cylinder 33 to further compress the elastic member 35, the diameter of the end of the composite pipe 1o is further expanded together with the seal member 20, as shown in FIG. As such, the outer circumferential surface of the end portion of the composite tube 10 is pressed against the inner circumferential surface of the outer mold 31.

At this time, the diameter of the seal member 20 bonded to the inner peripheral surface of the metal pipe 11 of the composite pipe 10 with an adhesive was expanded along with the end of the composite pipe 10, and the cylindrical seal member 20 was expanded in the circumferential direction. state, and stress in the direction of diameter reduction remains inside.

When a socket portion of a predetermined shape is formed at the end of the composite pipe IO,
The rod 32 is moved in the direction of advancing from the hydraulic cylinder 33, and the compression of the elastic member 35 by the pressing member 34 is released. Next, the fixation of the outer mold 31 is released to make it into a divided state,
The composite tube 10 is moved in the axial direction and removed from the elastic member 35. At this time, the hydraulic cylinder 33
may be moved to remove the elastic member 35 from within the end of the composite tube 10.

As a result, a socket having a predetermined structure is formed at the end of the composite pipe 10. At this time, as shown in FIG. 4, the tip of the tongue piece 22 of the sealing member 20 is pulled toward the proximal end by the stress remaining inside, and the tip is in a reduced diameter state. ing.

A predetermined insertion port is inserted into the socket of the composite pipe 10 formed in this way. The insertion port comes into sliding contact with the inner peripheral surface of the tongue piece 22 of the sealing member 20 and enters into the tongue piece 22. Then, the tip of the insertion part is connected to the locking part 21 of the seal body part 21.
b, the inner circumferential surface of the tongue piece 22 comes into contact with the outer circumferential surface of the insertion part, and the pressing part 22a provided on the tongue piece 22 presses against the inner circumferential surface of the seal main body part 21. It comes into contact with the surrounding surface. As a result, the tongue piece 22 is strongly brought into close contact with the outer circumferential surface of the insertion port. At this time, the tip of the tongue piece 22 of the seal member 20 is in a reduced diameter state due to stress remaining inside due to the bulging process.
The - layer is strongly adhered to the circumferential surface of the insertion part.

The metal tube 11 used in the composite tube 10 is not limited to steel, and tubes made of soft iron, copper, aluminum, lead, etc. can be used.

The synthetic resin layer 13 covering the inner peripheral surface of the metal tube 11 is not limited to polyvinyl chloride (PVC), but may also be made of polyethylene (
PE), crosslinked polyethylene, polybutene, polypropylene, fluororesin, etc. are used.

Next, regarding other embodiments of the socket forming method of the present invention,
This will be explained below. In this embodiment, first, the synthetic resin layer 13 and adhesive layer 12 at the end of the composite tube 10 are peeled off to expose the inner circumferential surface of the metal tube 11. Then, the diameter of the end portion of the composite tube is expanded into a predetermined shape by, for example, the bulging method described in the above embodiment. In this state, a sealing member 20 whose outer peripheral surface is coated with adhesive is placed inside the end of the composite pipe 10 whose diameter has been expanded, and the bulge used to expand the diameter of the end of the composite pipe 10 is installed. The processing machine 30 expands the diameter of the seal member 20 from the inside. Then, the expanded diameter state of the seal member 20 is maintained until the seal member 20 is adhered to the inner peripheral surface of the end portion of the composite pipe 10. As a result, a socket having a structure as shown in FIG. 4 is formed.

In this case as well, stress remains inside the sealing member 20, and the tip of the tongue 22 of the sealing member 20 is different from the initial state. The part is in a reduced diameter state.

Therefore, the tongue piece 22 of the sealing member 20 is tightly attached to the insertion opening into which it is inserted.

(Effects of the Invention) The method of manufacturing a composite pipe having a socket according to the present invention is such that the sealing member fitted to the end of the composite pipe is in a state where stress remains inside and the tongue Since the tip of the tongue is biased to contract in diameter, the tongue is strongly brought into close contact with the outer circumferential surface of the receptacle inserted into the sealing member, and the sealing effect of the sealing member is significantly improved.

[Brief explanation of drawings]

1 to 3 are cross-sectional views showing steps of an example of the method for forming a socket portion of the present invention, and FIG. 4 is a cross-sectional view of a socket portion formed by the method of the present invention. DESCRIPTION OF SYMBOLS 10... Composite pipe, 11... Metal tube, 12... Adhesive layer, 13... Synthetic resin layer, 20... Sealing member,
21... Seal main body part, 22... Tongue piece, 30...
Bulge forming machine, 31... Outer mold, 32... Mouth 7, 3
3... Pressure cylinder, 34... Pressing member, 35...
・Elastic member. that's all

Claims (1)

[Claims] 1. Peeling off the synthetic resin layer at the end of a composite tube in which a synthetic resin layer is bonded to the inner circumferential surface of the metal tube to expose the inner circumferential surface of the metal tube; A sealing member is provided with a cylindrical tongue piece that protrudes from one end of the seal body part inwardly to the innermost side of the seal body part, and the tongue piece projects in the direction of the composite pipe. a step of arranging it on the exposed inner peripheral surface of the metal tube at the end of the composite tube so as to be on the innermost side and bonding it to the metal tube; and a step of expanding the diameter into a predetermined shape. 2. A step of peeling off the synthetic resin layer at the end of the composite tube, in which the synthetic resin layer is bonded to the inner circumferential surface of the metal tube, to expose the inner circumferential surface of the metal tube, and expanding the end of the composite tube into a predetermined shape. a sealing member provided with a cylindrical tongue piece that gradually decreases in diameter and projects from one end of an elastic cylindrical seal body inward to the innermost side of the seal body; arranging the tongue piece at the exposed end of the metal pipe of the composite pipe so that the protruding direction of the tongue piece is on the inner side of the composite pipe; and expanding the diameter of the seal member from the inside to seal the seal member. A method for forming a socket portion of a composite pipe, comprising the steps of: maintaining the enlarged diameter state of the seal main body portion of the member so as to adhere to the exposed inner circumferential surface of the metal pipe of the composite pipe.