JPH0972477A - Coupling for resin pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coupling for a resin pipe to facilitate connection to and separation from a resin pipe. SOLUTION: A coupling core 14 is incorporated in a coupling base body 10. An expansion chuck 23 is incorporated in the outer periphery of the coupling core 14 and the coupling base body 10. In the expansion chuck 23, when the chuck is inserted in the whole of a resin pipe, each lock claw part 27 is contracted through press from the inner surface of a hole and in such a state to be inserted in the resin pipe, each lock claw part 27 is expanded. A head 34 is slidably supported at the tip of the coupling core 14. A head 34 has a seal means 40 to seal a part making contact with the inner surface of the resin pipe. When pressure fluid is fed in the resin pipe, the head is moved backward and each lock claw part 27 is contracted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin pipe joint which is inserted into a resin pipe for connection.

[0002]

2. Description of the Related Art For example, a long resin hose is manufactured by using a resin hose manufacturing core made of a hard resin round bar, and extruding and coating a resin on the outer circumference of the resin hose manufacturing core. After manufacturing the resin hose, the core for manufacturing the resin hose is removed. This resin hose manufacturing core 1 is shown in FIG.
It is manufactured as a standard length as shown in, and a plurality of these are connected to have a required length.

Conventionally, as shown in FIG. 7, a metal resin pipe joint 2 is used to connect these resin hose manufacturing cores 1,
It was performed using the resin pipe 3. That is, in the resin pipe joint 2, a screw portion 5 is projectingly provided at one end of a disk-shaped joint base 4 having the same outer diameter as the core 1, and an insertion portion 7 having a thickness to be inserted into the hole 6 of the resin pipe 3 at the other end. It was a structure with and. In such a joint 2 for a resin pipe, the threaded portion 5 is screwed to the end of the resin hose manufacturing core 1, and the insertion portion 7 is inserted into the hole 6 of the resin pipe 3 having the same outer diameter as the core 1. And was connected with the resin pipe 3 by bonding with the adhesive 8. By performing such a connecting work at both ends of the resin hose manufacturing cores 1, the resin hose manufacturing cores 1 adjacent to each other via the connecting body 9 using the resin pipe joint 2 and the resin pipe 3 are connected. I was making a connection.

The resin hose A is attached to the outer circumference of the resin hose manufacturing core 1 by extruding and covering the outer circumference of the resin hose manufacturing core 1 thus connected to the required length.
Is formed. After the manufacturing work of the resin hose A is completed, the resin hose manufacturing core 1 is disassembled at the position of the connection body 9 and returned to the original length. At this time, conventionally, the connection portion 9 was broken by hitting the bonded portion with the adhesive 8 with a hammer to separate the insertion portion 7 from the resin pipe 3.

[0005]

However, in such a conventional connection method using the resin pipe joint 2 and the resin pipe 3, (a) the adhesive strength changes depending on the application state of the adhesive 8. b) Since the adhesive 8 is used, the connection work is troublesome. (c) Since the adhesive 8 is used, it takes time to separate the connection body 9. (d) Since the adhesive 8 is used, the bonded state is stable. There was a problem that it took a long time to do so that the work could not be carried out continuously.

It is an object of the present invention to provide a resin pipe joint which can be connected to a resin pipe without using an adhesive.

[0007]

A resin pipe joint according to the present invention comprises a joint base body, a joint core body incorporated in the joint base body, and an outer periphery of the joint core body incorporated in the joint base body. It has a plurality of locking claws in the circumferential direction, and the locking claws are in a diameter expanded state by the elastic action in the diameter expansion direction, and when inserted into the hole of the resin pipe A diameter-expanding chuck in which the locking claws are pressed to reduce their diameters, and when inserted into the resin pipe, the locking claws are locked to the inner surface of the resin pipe by the elastic action in the radial expansion direction. And a sealing means that is slidably supported at the tip of the joint core and that seals a portion in contact with the inner surface of the resin pipe on the outer periphery, and retreats when pressure fluid is fed into the resin pipe. And a head for reducing the diameter of each of the locking claws. And said that you are.

As described above, the joint base body, the joint core body incorporated in the joint base body, and the plurality of locking claw portions which are incorporated in the joint base body on the outer periphery of the joint core body in the circumferential direction are provided. The locking claw portion is in a diameter expanded state by the elastic action in the diameter expanding direction, and when the locking claw portion is inserted into the hole of the resin pipe, the locking claw portion is pressed by the inner surface of the hole of the resin pipe to reduce the diameter of each locking claw portion. In addition, since each locking claw portion is provided with a diameter-expanding chuck that locks to the inner surface of the resin pipe by the elastic action in the diameter-expanding direction when inserted in the resin pipe, the hole of the resin pipe to be connected When inserted from the head side, each locking claw is pushed by the inner surface of the hole of the resin pipe and the diameter is automatically reduced, which does not hinder the insertion into the resin pipe, and when the insertion is completed, the Each locking claw part that receives elastic action locks on the inner surface of the hole of the resin pipe,
When a pulling force is applied to separate the resin pipe from the resin pipe joint in this state, each locking claw portion bites into the inner surface of the resin pipe and is prevented from coming off. As a result, according to the resin pipe joint of the present invention, it is not necessary to provide a waiting time until the adhesive is solidified as in the conventional example using an adhesive, and moreover, the diameter expansion chuck is simply inserted into the resin pipe. Connection can be done by one-touch operation, so connection work can be done efficiently.

Further, the joint core is slidably supported on the tip of the joint core, and has a sealing means on the outer periphery for sealing a portion in contact with the inner surface of the resin pipe, and when pressure fluid is fed into the resin pipe. Since the head for retracting and retracting each locking claw portion to reduce the diameter is provided, when the resin pipe joint is pulled out from the resin pipe, the head is moved by sending a pressure fluid into the resin pipe. The locking claw portions can be pushed back to reduce the diameter, and thereafter, the resin pipe joint can be pushed out of the resin pipe by the pressure of the pressure fluid. Therefore, it is possible to easily and efficiently remove the resin pipe joint from the resin pipe.

Further, the resin pipe joint according to the present invention is
A joint base, a joint core, a diameter-expanding chuck, a coil spring, a head, and a sealing means are provided. The joint base is provided with a pipe insertion cylinder portion and a bottomed hole communicating with the pipe insertion cylinder portion. The joint core has a columnar shape, and is inserted concentrically with the inner wall of the bottomed hole of the joint base to secure a chuck mounting space, and the base is fixed to the bottom of the bottomed hole. A chuck diameter-increasing operation convex portion is provided at a portion protruding from the tip of the pipe insertion cylinder portion, and a small diameter column is provided at a portion between the chuck diameter-increasing operation convex portion and the base portion so as to provide an escape concave portion for chuck diameter reduction. Is formed as a portion, and has a structure in which a head mounting portion is provided at a location that protrudes ahead of the chuck diameter-expanding operation convex portion, and the diameter-expansion chuck is made of a tubular metal, and is formed from an annular base portion. Swipe the front part at a predetermined interval in the circumferential direction. And a plurality of elastic tongues are provided along the longitudinal direction, and locking claws are respectively provided on the outer surfaces of the tips of these elastic tongues. The outer surfaces of the locking claws extend from the front to the rear. The taper outer surface increases in height toward, and the rear end of these taper outer surfaces is a locking edge portion, and the inner surface of the tip of each of the locking claws has a height from the tip to the rear. It has a taper inner surface that becomes lower,
It is incorporated in a chuck built-in space so as to be movable in the axial direction, and is moved forward by the elastic force of the coil spring mounted between the chucked space and the bottomed hole so that the inner taper surface of each locking claw portion is the chuck diameter-increasing operation convex portion. The engaging claws are urged to expand the diameter, and the head is slidably fitted in the head mounting portion of the joint core and is supported by the stopper means so as not to be pulled out by the head mounting portion. The rear end surface is provided with a taper inner surface that presses the locking claw portion in the diameter reducing direction at an inclination angle that matches the inclination of the tapered outer surface of the locking claw portion,
The sealing means is supported on the outer circumference of the head so as to slidably contact the inner surface of the resin pipe for sealing.

By thus providing the chuck diameter-increasing operation convex portion on the joint core, each locking claw portion at the tip of the diameter-expansion chuck is pressed against the chuck diameter-expanding operation convex portion by the bias of the coil spring. The diameter of each locking claw portion can be easily expanded. Also, by forming the portion between the chuck diameter-increasing operation convex portion and the base portion of the joint core body as a small-diameter column portion to provide an escape concave portion for chuck diameter reduction, each locking claw is provided in the escape concave portion. Can escape the section,
The diameter of each locking claw portion can be easily reduced. Further, by providing each locking claw portion of the diameter expansion chuck at the tip of each elastic tongue, the diameter expansion and diameter reduction operations of each elastic tongue can be easily performed. Further, by providing the outer surface of each locking claw portion with a tapered outer surface whose height increases from the tip to the rear, insertion into the resin pipe and pressing of the head by the taper inner surface can be easily performed. Also,
By providing a tapered inner surface on the inner surface of the tip of each locking claw, the height of which decreases from the front to the rear, each locking claw can be easily mounted on the chuck expansion operation convex portion by the biasing force of the coil spring. It is possible to expand the diameter.

When such a resin pipe joint is inserted into the hole of the resin pipe to be connected from the head side, the locking claws are pushed by the inner surface of the hole of the resin pipe, and the expanding chuck resists the elastic force of the coil spring. Then, when the locking claw portion is disengaged from the chuck diameter-increasing operation convex portion of the joint core, the locking claw portion is automatically reduced in diameter at the position of the chuck diameter reducing relief recess, and the locking claw portion is moved to the resin pipe. When the insertion is completed without any obstruction to the insertion, the locking claw part of the diameter expansion chuck, which is biased in the forward direction by the elastic force of the coil spring, rides on the chuck diameter expansion operation convex part and its locking edge part is made of resin. When the elastic force is applied to the inner surface of the pipe and the pulling force that separates the resin pipe from the resin pipe joint is applied from this state, each locking claw part tries to move in the pulling direction. The tree is pressed in the radial direction by the convex portion. It is fit retaining bites into the inner surface of the pipe. As a result, according to the resin pipe joint of the present invention, it is not necessary to provide a waiting time until the adhesive is solidified as in the conventional example using an adhesive, and moreover, the diameter expansion chuck is simply inserted into the resin pipe. Since the connection can be made securely by one-touch operation, the connection work can be performed efficiently.

Further, the head is slidably fitted to the head mounting portion of the joint core, and the outer periphery of the head is provided with sealing means for slidably contacting the inner surface of the resin pipe for sealing. When pressure fluid is sent into the resin pipe, the head moves backward due to the pressing of this pressure fluid, and this retracting head causes the locking claw portion to retract the diameter-expanding chuck that is biting into the inner surface of the resin pipe, and the locking claw At the position where the part deviates from the chuck expansion operation convex portion of the joint core, the inner taper surface of the head presses the outer taper surface of the locking claw portion, so that each locking claw portion is reduced in diameter and its locking edge portion is After the resin pipe is disengaged from the inner surface, the resin pipe joint can be pushed out of the resin pipe by the pressure of the pressure fluid. Therefore, it is possible to easily and efficiently remove the resin pipe joint from the resin pipe.

[0014]

1 and 2 show an example of an embodiment of a joint for a resin pipe according to the present invention.
The joint for resin pipes of the present example has a joint base 10 having the same outer diameter as the core 1 for producing a resin hose described above.
A threaded portion 11 is projectingly provided at one end of the. The joint base 1
At the other end of 0, a pipe insertion cylinder portion 12 for inserting into the above-mentioned resin pipe 3 is projected. The outer peripheral surface of the pipe insertion cylinder portion 12 is a tapered surface that gradually increases from the tip end toward the base portion so that the resin pipe 3 can be easily inserted into the hole 6. On the other end side of the joint base body 10, the pipe insertion cylinder 1
A bottomed hole 13 having an inner diameter of 2 is provided.

Further, on the other end side of the joint base body 10, the base 15 side of the columnar metal joint core body 14 is concentric with the inner wall of the bottomed hole 13 to secure a predetermined chuck mounting space 16. And is fixed to the joint base 10 by screwing a screw portion 17 provided at the base end of the base portion 15 into the bottom portion of the bottomed hole 13. The joint core body 14 is provided with a ring-shaped chuck diameter-increasing operation convex portion 18 at a portion protruding from the tip of the pipe insertion cylinder portion 12, and a portion between the chuck diameter-increasing operation convex portion 18 and the base portion 15. Is a small-diameter column portion 20 for providing a relief recess 19 for reducing the diameter of the chuck. The joint core body 14 is provided with a small-diameter head mounting portion 21 at a portion protruding ahead of the chuck diameter-expanding operation convex portion 18. The head mounting portion 21 is provided with a head mounting elongated hole 22 in the longitudinal direction thereof.

A cylindrical metal diameter expanding chuck 23 is incorporated in the chuck incorporating space 16. The diameter-expanding chuck 23 is provided with a plurality of elastic tongue pieces 26 at predetermined portions in the circumferential direction along the longitudinal direction at a portion ahead of the annular base portion 24, and the tips of these elastic tongue pieces 26 are provided. Locking claws 27 are provided on the outer surface, respectively.
The outer surfaces of these locking claws 27 are tapered outer surfaces 28 whose height increases from the tip to the rear, and the rear ends of the tapered outer surfaces 28 are locked by the tapered outer surfaces 28 and the vertical surfaces 29. The edge portion 30 is formed, and the vertical surface 29 is lowered toward the rear portion.
A taper surface 31 is formed which is pressed in the direction of diameter reduction at the tip of 2. The inner surfaces of the tips of the locking claws 27 are tapered inner surfaces 32 whose height decreases from the front to the rear.

The expanded diameter chuck 13 is fitted in the outer periphery of the joint core body 14 and is assembled in the chuck assembly space 11 so as to be movable in the axial direction. Between the bottomed hole 13 of the joint base 10 and the diameter expanding chuck 13, the diameter expanding chuck 1
Coil spring 33 for pressing 3 in the forward direction by elastic force
Is installed.

When the taper inner surface 32 of each locking claw portion 27 of the diameter expanding chuck 13 which is advanced by the elastic force of the coil spring 33 hits the chuck diameter expanding operation convex portion 18, the coil spring 33 and the chuck diameter expanding operation convex are formed. As a result of the interaction with the portion 18, each locking claw portion 27 is pushed outward and expanded in diameter, so that the locking edge portion 30 of each locking claw portion 27 of the pipe insertion tube portion 12 is expanded as shown in FIG. It is designed to project outward from the outer circumference.

A head 34 having an outer diameter substantially equal to the inner diameter of the resin pipe 3 is fitted to the head mounting portion 21 of the joint core 14 so as to be movable in the axial direction. That is,
The head 34 is provided with a mounting portion sliding hole 35 into which the head mounting portion 21 is slidably fitted, in a predetermined range from the rear end toward the front portion, and the chuck diameter expanding operation protrusion is provided on the rear end side. Part 1
A recess 36 is provided with an inner diameter into which 8 can be inserted. On the rear end surface of the head 34, a tapered outer surface 28 of the locking claw 27 is formed.
The tapered inner surface 37 is provided at an inclination angle according to the inclination of the. The head 34 is supported by a stopper pin 38 which passes through the head 34 and passes through the head mounting elongated hole 22 so as not to be pulled out.

By moving the head 34, which is movably fitted to the head mounting portion 21, to the rear end side, the head 34 is moved.
The expanding chuck 13 is pressed by the rear end surface of the coil spring 33.
Of the joint core body 14 with the locking claw portion 27 retracting against the elastic force of
Of the head 3 at a position deviated from the chuck diameter expanding operation convex portion 18
The outer taper surface 2 of the locking claw 27 is formed by the inner taper surface 37 of 4
By pressing 8, the diameter of each locking claw portion 27 is reduced, and the locking edge portion 30 is placed inside the outer peripheral surface of the pipe insertion tubular portion 12.

A ring groove 39 is provided on the outer circumference of the head 34 in the circumferential direction, and the ring groove 39 slidably contacts the inner surface of the resin pipe 3 for sealing.
A sealing means 40 consisting of a ring is incorporated. Further, a driver groove 41 for turning the screw portion 11 of the joint core body 14 through the head 34 is provided on the tip end surface of the head 34.

Next, a process of connecting the resin pipe joint to the resin pipe 3 will be described with reference to FIGS. 3, 4, and 5. The resin pipe joint is connected in advance by screwing its threaded portion 11 to the corresponding end of the resin hose manufacturing core 1.

The resin pipe joint is inserted into the hole 6 of the resin pipe 3 from the head 34 as shown in FIG. By inserting the head 34, the sealing means 40 also moves while being in contact with the inner circumference of the resin pipe 3. next,
The taper outer surface 28 of each locking claw portion 27 of the diameter expanding chuck 23 contacts the inner surface of the resin pipe 3, and the diameter expanding chuck 23 retracts against the pressing force of the coil spring 33 under the pressing force.
Each locking claw 27 is disengaged from the chuck diameter-increasing operation convex portion 18 and escapes into each locking claw 27 escape recess 19, whereby the tip end side of the diameter expansion chuck 23 is reduced in diameter as shown in FIG. In this state, the resin pipe 3 has the locking claw portions 27.
And is fitted to the outer circumference of the pipe insertion tube portion 12. When the insertion is completed, the locking claw portion 27 of the diameter-expanding chuck 23, which is biased in the forward direction by the elastic force of the coil spring 33, rides on the chuck diameter-expanding operation convex portion 18, and the locking edge portion 30 of the locking claw portion 30 is applied to the resin pipe 3. It is elastically locked to the inner surface of, and this completes the connection work of the resin pipe joint to the resin pipe 3. Such connection work is performed on both sides of the resin pipe 3. In this state, the resin hose manufacturing core 1 is connected by the resin pipe joint and the resin pipe 3 as described above,
The connection body 9 described above is formed.

In this state, when a pulling force is applied to the resin pipe 3 to pull it out of the joint for the resin pipe, the chuck expanding diameter of the joint core body 14 in which each locking claw portion 27 tends to move in the pulling direction. It is pressed in the radial direction by the operation convex portion 18 and cuts into the inner surface of the resin pipe 3 as shown in FIG.

The resin hose manufacturing core 1 thus connected to the required length is used to manufacture the resin hose as described above. After the resin hose manufacturing operation is completed, the resin hose manufacturing core 1 is disassembled at the location of the connector 9 as described above, and the resin hose manufacturing core 1 is returned to the original length.

In this case, the resin pipe 3 is cut in the middle of its length, and a pressure fluid such as compressed air is fed into the resin pipe 3 from the cut end. When the pressure fluid is fed into the resin pipe 3, the head 34, which has the sealing means 40 on the outer circumference and is sealed between the inner surface of the resin pipe 3 and the head 34, is retracted by the pressure of the pressure fluid as shown in FIG. To do. When the head 34 retreats, the taper inner surface 37 at the rear end of the head 34 abuts the taper outer surface 28 of each locking claw portion 27 to press the enlarged diameter chuck 23 backward against the pressing force of the coil spring 33. When each locking claw portion 27 is disengaged from the chuck diameter-increasing operation convex portion 18 due to the retraction of the diameter-expansion chuck 23,
The taper inner surface 37 of the head 34 presses the taper outer surface 28 of the locking claw portion 27, so that each locking claw portion 27 escapes to the recessed portion 19 and the diameter is reduced, and the locking edge portion 30 of the resin pipe 3 is formed. When it comes off from the inner surface and comes to this state, the resin pipe joint 2 is entirely retracted by the pressing force of the pressure fluid and pushed out of the resin pipe 3.

Therefore, the connecting body 9 can be easily disassembled simply by sending the pressure fluid into the resin pipe 3. The pressure fluid is not limited to gas such as compressed air,
It may be a liquid such as water.

Of course, the resin pipe joint of the present invention can be used for connecting short or long resin pipes for other purposes.

[0029]

According to the joint for resin pipes of the present invention, when the resin pipe and the joint for resin pipe are connected, they can be connected by a one-touch operation such as simply inserting a diameter-expanding chuck into the resin pipe. Since the resin pipe joint can be pushed and separated out of the resin pipe by the pressure of the fluid sent into the resin pipe in the separation, the connection and separation work of the resin pipe and the resin pipe joint can be efficiently performed. Can be done well.

[Brief description of drawings]

FIG. 1 is a partially longitudinal side view showing an example of an embodiment of a joint for a resin pipe according to the present invention.

FIG. 2 is a side view of the diameter expansion chuck used in the example of FIG.

FIG. 3 is a partial vertical cross-sectional side view showing a state in which the resin pipe joint of this example is connected to a resin pipe.

FIG. 4 is a partially longitudinal side view showing the operation of the diameter-expanding chuck in a state where a pulling force is applied from the resin pipe to the resin pipe joint of this example.

FIG. 5 is a partially longitudinal side view showing a state in which the resin pipe joint of this example is separated from the resin pipe.

FIG. 6 is a side view showing a connected state of a resin hose manufacturing core.

7 is a vertical cross-sectional view of the connection body of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Core for manufacturing resin hose 2 Joint for resin pipe 3 Resin pipe 4 Joint base 5 Screw part 6 hole 7 Insertion part 8 Adhesive 9 Connection body 10 Joint base 11 Screw part 12 Pipe insertion tube part 13 Bottomed hole 14 Joint core body 15 Base 16 Chuck Incorporating Space 17 Screw Part 18 Chuck Enlarging Operation Convex Part 19 Relief Recess 20 Small Diameter Column 21 Head Mounting Part 22 Head Mounting Long Hole 23 Expanding Chuck 24 Annular Base 25 Slit 26 Elastic Tongue 27 Locking Claw Part 28 Tapered outer surface 29 Vertical surface 30 Locking edge portion 31 Tapered surface 32 Tapered inner surface 33 Coil spring 34 Head 35 Mounting portion sliding hole 36 Recess 37 Tapered inner surface 38 Stopper pin 39 Ring groove 40 Sealing means 41 Driver groove

Claims (2)

[Claims] 1. A joint for a resin pipe inserted into a hole of a resin pipe for connection, a joint base, a joint core body incorporated in the joint base, and an outer periphery of the joint core incorporated in the joint base. And has a plurality of locking claws in the circumferential direction, and the locking claws are in a diameter-expanded state due to the elastic action in the diameter-expanding direction. When the locking claws are pressed by the inner surface to reduce the diameter, and when the locking claws are inserted into the resin pipe, the elastic claws in the diameter expanding direction cause the locking claws to lock the inner surface of the resin pipe. A diameter chuck and slidably supported on the tip of the joint core and sealing means on the outer periphery for sealing the portion in contact with the inner surface of the resin pipe, and the pressure fluid is fed into the resin pipe. And a head that retracts to reduce the diameter of each locking claw portion. A joint for resin pipes, which is characterized by being configured as follows. 2. A joint for a resin pipe which is inserted into a hole of a resin pipe for connection, the joint base, the joint core body, a diameter expanding chuck, a coil spring, a head and a sealing means, wherein the joint base has a pipe insertion tube. A projecting part and a bottomed hole communicating with the pipe insertion cylinder part, the joint core is columnar, and a chuck mounting space is secured with respect to the inner wall of the bottomed hole of the joint base. Then, the base portion is fixed to the bottom portion of the bottomed hole by being inserted concentrically, and a chuck diameter-increasing operation convex portion is provided at a portion protruding from the tip of the pipe insertion cylinder portion. The portion between the base portion and the base portion is formed as a small-diameter column portion to provide a relief recess for reducing the diameter of the chuck, and a head mounting portion is provided at a portion protruding ahead of the chuck diameter-increasing operation convex portion. The expansion chuck is It is made of metal in the shape of a cylinder, and a plurality of elastic tongues are provided in the portion ahead of the annular base at predetermined intervals in the circumferential direction along the longitudinal direction, and the outer surface of the tip of these elastic tongues is provided. Locking claws are provided on each of the locking claws, and the outer surfaces of these locking claws are tapered outer surfaces whose height increases from the front end to the rear part. The inner surface of the tip of each of the locking claws is a tapered inner surface whose height decreases from the front to the rear, and is movably incorporated in the chuck incorporating space in the axial direction. Is advanced by the elastic force of the coil spring mounted between, and the tapered inner surface of each locking claw portion hits the chuck diameter-increasing operation convex portion, and is biased so that each locking claw portion is expanded in diameter. The head slides on the head mounting portion of the joint core. And is supported by the stopper means so as not to be pulled out of the head mounting portion, and the rear end face is pressed in the diameter reducing direction with the inclination angle corresponding to the inclination of the taper outer surface of the retaining claw portion. A joint for a resin pipe, wherein a taper inner surface is provided, and the sealing means is supported on the outer circumference of the head so as to slidably contact the inner surface of the resin pipe for sealing.