JP6747874B2 - Hard resin pipe connection structure and connection method - Google Patents

Description

The present invention relates to a structure and a connecting method for connecting hard resin pipes such as a fiber reinforced plastic pipe (hereinafter referred to as “FRP pipe”) and a fiber reinforced plastic composite pipe (hereinafter referred to as “FRPM pipe”), and in particular, one The hard resin pipe connection structure and the connecting method, in which the other hard resin pipe is inserted into the receiving port of the hard resin pipe.

Generally, a receiving port is formed at one end of a hard resin pipe such as an FRP pipe or a FRPM pipe, and an insertion port is formed at the other end. When connecting two hard resin pipes, the insertion port of the other hard resin pipe is inserted into the receiving port of one hard resin pipe. In this type of hard resin pipe connection structure, an annular seal member is provided on the inner peripheral surface of the tip of the receiving port to seal the outer peripheral surface of the insertion port (hereinafter referred to as C type). ), and a seal member is provided on the outer peripheral surface of the distal end portion of the insertion opening to seal between the inner peripheral surface of the receiving opening (hereinafter, referred to as B type).

When an earthquake or an increase in pipe pressure occurs, a pulling force acts between the hard resin pipes, which may disconnect the hard resin pipes. In order to prevent this, in both the C type and the B type, a receiving side separation prevention member is provided on the inner peripheral surface of the receiving opening, and an insertion side separation prevention member is provided on the outer peripheral surface of the insertion opening. (See Patent Document 1 etc.). When the hard resin pipes are connected to each other, it is necessary that the detachment prevention member on the side of the receiving port and the insertion port where the seal member is not provided ride over the seal member and further over the detachment prevention member on the mating side.

JP 2001-263557 A

Since a normal resin pipe such as a polyolefin resin pipe or a vinyl chloride pipe can be elastically deformed, it is not so difficult for each separation preventing member to get over the seal member and further to get over the mating separation preventing member. However, since a hard resin pipe such as an FRP pipe is hardly elastically deformed, it is necessary to apply a large insertion force at the time of connection. If the insertion force is too large, the hard resin pipe may be damaged or the seal member may be damaged.
In view of the above circumstances, it is an object of the present invention to provide a hard resin pipe connection structure and a connection method capable of improving the connection workability of a hard resin pipe and preventing or reducing damage to a seal member.

In order to solve the above problems, the present invention is a hard resin pipe connection structure comprising one hard resin pipe having a receiving port and the other hard resin pipe having an inserting port inserted into the receiving port,
An annular seal member provided on the inner peripheral surface of the receiving opening and sealing between the outer peripheral surface of the insertion opening,
A receiving side separation preventing member provided on the inner peripheral surface of the receiving port on the tip side of the sealing member,
An insertion side separation prevention member provided on the outer peripheral surface of the insertion opening, wherein the insertion side separation prevention member in the connection state of the hard resin pipes is between the receiving side separation prevention member and the seal member. It is arranged in.

According to the present invention, in the C-shaped hard resin pipe connection structure, when the receiving port and the insertion port are connected, it is not necessary for the insertion side detachment prevention member of the insertion port to cross over the sealing member of the receiving port. As a result, the insertion force or the work amount at the time of connecting the hard resin pipe can be reduced, and the workability of connecting the hard resin pipe can be improved. Moreover, damage to the seal member can be prevented or reduced.
Here, the hard resin refers to a resin having a hardness higher than that of a general polyolefin resin or polyvinyl chloride. The elastic modulus of the hard resin is preferably 30,000 kgf/cm ² (3000 MPa) or more.

At least one of the receiving-side separation prevention member and the insertion-side separation prevention member is preferably more elastic than the hard resin pipe.
This can surely reduce the insertion force when the separation preventing members pass over each other.

It is preferable that the receiving-side detachment preventing member is bonded or can be bonded to the receiving port.
The receiving side separation preventing member can be manufactured separately from the receiving port and attached to the receiving port. The receiving side separation prevention member may be adhered to the receiving port before connecting the hard resin pipes, separated from the receiving port when inserting the insertion port into the receiving port, and bonded to the receiving port after insertion. Good.
The receiving side separation preventing member may be integrated with the receiving port. The receiving side separation prevention member may be formed integrally with the reception port by providing a molding portion of the reception side separation prevention member in the molding die of the reception port.
The insertion side detachment prevention member can be manufactured separately from the insertion opening and attached to the insertion opening. The insertion side detachment prevention member may be adhered to the insertion port, or may be fixed by a mechanical fixing means such as a screw.
The insertion side detachment prevention member may be integrated with the insertion port. A molding portion of the insertion side detachment prevention member may be provided in the molding die of the insertion port, and the insertion side detachment prevention member may be formed integrally with the insertion port.

A fitting groove is formed on the inner peripheral surface of the receiving port,
It is preferable that the receiving-side detachment preventing member is formed with a locking projection that is fitted into the fitting groove.
As a result, the joint strength between the receiving side separation prevention member and the receiving port can be increased. Further, the locking strength when the pulling force is applied can be increased.

The receiving side separation prevention member may include a main body portion arranged on an inner peripheral surface of the receiving opening, and a flange provided at a front end portion of the main body portion and covering a front end surface of the receiving opening. .. As a result, the joint strength between the receiving side separation prevention member and the receiving port can be increased. When inserting the insertion opening into the receiving opening, the receiving end separation preventing material may be peeled off by catching the receiving end separation preventing material on the receiving end separation preventing material. In that case, if there is a flange, it is possible to prevent the receiving side separation preventing material from being peeled off even if it is slightly hooked. When the receiving side separation preventing material is mounted on the receiving opening after the insertion opening is inserted into the receiving opening (fifth to eighth embodiments (see FIGS. 9 to 16), the flange serves as a stopper at the time of mounting. ..
The flange on the receiving side separation prevention member may not necessarily be provided.
The entire outer peripheral surface of the main body portion arranged on the inner peripheral surface of the receiving opening in the receiving side separation prevention member may have a smooth cylindrical surface shape without irregularities such as the locking projections. Thus, when the receiving side separation prevention member and the receiving port are bonded together, the adhesive can be applied easily and evenly, and the receiving side separation preventing member and the receiving port can be reliably joined.

The inner peripheral surface of the receiving port is formed with a tapered recessed portion that expands in diameter toward the back side,
The outer peripheral surface of the receiving side separation prevention member has a tapered shape that expands in diameter toward the back side,
It is preferable that the receiving side separation prevention member is housed in the tapered recess.
Thus, even if the receiving-side separation prevention member is peeled off from the receiving opening, the receiving-side separation prevention member can be left between the receiving opening and the insertion opening. As a result, it is possible to reliably prevent the hard resin tubes from coming off from each other.

It is preferable that the receiving side separation preventing member is attachable to and detachable from the receiving port.
When inserting the insertion port into the receiving port, the receiving side separation prevention member is separated from the receiving port so that the insertion side separation prevention member does not have to cross over the receiving side separation prevention member, and when connecting hard resin pipes. The insertion force of can be further reduced. Further, even after the connection is made once, the hard resin pipes can be separated from each other by removing the receiving side separation prevention member, and the connection work can be redone.

It is preferable that the receiving-side detachment preventing member has an annular shape having a notch portion at one position in the circumferential direction and is expandable and contractable.
As a result, it is possible to facilitate the work of mounting the receiving side separation prevention member in the receiving port.

The hard resin pipe connection structure,
An annular ring having a ring cutout portion at one position in the circumferential direction, and a locking ring interposed between the receiving side separation prevention member and the insertion side separation prevention member in the connected state,
An expansion/contraction operation unit that is provided in the receiving opening and is operable to operate the locking ring between an expanded diameter state and a reduced diameter state,
In the expanded diameter state, the locking ring is locked in the receiving port, and the inner diameter of the locking ring is larger than the outer diameter of the insertion side detachment prevention member,
In the reduced diameter state, it is preferable that the locking ring is pressed against the insertion opening, and the outer diameter of the locking ring is larger than the inner diameter of the receiving side separation preventing member.
When inserting the insertion opening into the receiving opening, it is possible to avoid interference between the insertion side detachment prevention member and the engagement ring by expanding the diameter of the engagement ring. This can significantly reduce the required insertion force. After inserting the insertion opening to a predetermined position in the receiving opening, the locking ring can be reduced in diameter to be pressed against the outer peripheral surface of the insertion opening to be fixed. When the releasing force is applied, the separation preventing members can be locked via the locking ring.

It is preferable that the expansion/contraction operation part includes a window part formed in the receiving port and a diameter expansion piece that can be inserted into and taken out from the window part and fitted into the ring cutout part.
The locking ring can be in the expanded diameter state by fitting the expanded diameter piece into the ring notch through the window. The locking ring can be brought into the reduced diameter state by taking out the enlarged diameter piece from the ring notch.

The method of the present invention is a method of connecting the hard resin tubes to each other,
With the receiving side separation prevention member removed from the receiving opening, the insertion opening is inserted into the receiving opening,
After that, the receiving side separation preventing member is attached to the receiving port.
When inserting the insertion opening into the receiving opening, the insertion-side removal preventing member does not have to cross over the receiving-side removal preventing member, and the required insertion force can be reliably reduced. As a result, the connection workability of the hard resin pipe can be improved.

ADVANTAGE OF THE INVENTION According to this invention, the connection construction work of a hard resin pipe can be improved, and the damage of a sealing member can be prevented or reduced.

FIG. 1 is a front view showing a hard resin pipe connection structure according to a first embodiment of the present invention in a state where two hard resin pipes are connected to each other. FIG. 2 is a plan cross-sectional view of the hard resin pipe connection structure in the connection state, taken along the line II-II in FIG. FIG. 3 is a plan cross-sectional view showing the receiving port and the insertion port of the hard resin pipe connection structure before connection. FIGS. 4A to 4C are cross-sectional views sequentially showing a connecting process of hard resin pipes. FIG. 5 is a cross-sectional view showing a state when a pulling force acts on two hard resin pipes. FIG. 6 is a sectional view showing a second embodiment according to a modification of the receiving side separation prevention member provided in the receiving port. FIG. 7A is a sectional view showing a third embodiment according to another modification of the receiving side separation prevention member provided in the receiving port. FIG. 7B is a cross-sectional view showing a state when a pulling force acts on the hard resin pipe connection structure of the third embodiment. FIG. 8 is a cross-sectional view showing a fourth embodiment according to another modification of the receiving side separation prevention member provided in the receiving port. FIG. 9 is a cross-sectional plan view showing the hard resin pipe connection structure according to the fifth embodiment of the present invention in a state before connection between the receiving port and the insertion port. 10A to 10C are cross-sectional views sequentially showing a step of connecting hard resin pipes in the hard resin pipe connection structure according to the fifth embodiment. FIG. 11 is a cross-sectional plan view showing the hard resin pipe connection structure according to the sixth embodiment of the present invention in a state before connection between the receiving port and the insertion port. 12A to 12C are cross-sectional views sequentially showing a connecting process of hard resin pipes in the hard resin pipe connecting structure according to the sixth embodiment. FIG. 13 is a cross-sectional plan view showing the hard resin pipe connection structure according to the seventh embodiment of the present invention in a state before connection between the receiving port and the insertion port. 14A to 14C are cross-sectional views sequentially showing a step of connecting hard resin pipes in the hard resin pipe connection structure according to the seventh embodiment. FIG. 15 is a perspective view of a receiving side separation preventing member according to the eighth embodiment of the present invention. 16A to 16C are cross-sectional views sequentially showing a step of connecting hard resin pipes in the hard resin pipe connection structure according to the eighth embodiment. FIG. 17 is a front view showing the hard resin pipe connection structure according to the ninth embodiment of the present invention in a state in which a part of the hard resin pipe connection structure is in a state before connection with the receiving port and the insertion port. FIG. 18A is a side view showing the locking ring of the ninth embodiment in a natural state. FIG. 18(b) is a side view showing the locking ring in a state where the diameter thereof is expanded by the diameter expansion piece. 19A to 19C are cross-sectional views sequentially showing a step of connecting hard resin pipes in the hard resin pipe connection structure according to the ninth embodiment. FIG. 20A is a sectional view showing the hard resin pipe connection structure according to the ninth embodiment in a state where two hard resin pipes are connected to each other. FIG. 20(b) is a cross-sectional view showing a state in which a pulling force is applied to the hard resin pipe connection structure of the third embodiment. FIG. 21A is a cross-sectional view of the socket along the line XXIa-XXIa in FIG. 17, showing the locking ring in the expanded state. FIG. 21B is a cross-sectional view showing the state in which the insertion opening is inserted into the receiving opening and the locking ring is reduced in diameter in FIG. FIG. 22: is a front view which shows the receptacle which concerns on 10th Embodiment of this invention in a partial cross section.

Embodiments of the present invention will be described below with reference to the drawings.
<First Embodiment>
1 to 5 show a first embodiment of the present invention. As shown in FIG. 1, the present embodiment relates to a connection structure 1 of a plurality (two in the figure) of hard resin pipes 10. These hard resin pipes 10 are arranged in a row and used as, for example, a sewer pipe, an agricultural water pipe, or the like. Each hard resin tube 10 is made of a hard resin such as FRP or FRPM. Each hard resin pipe 10 has a pipe body 11 having a circular cross section. A receiving port 12 is provided at one end (left end in FIG. 1) of the pipe body 11 in each hard resin pipe 10, and an insertion port 13 is provided at the other end (right end in FIG. 1). As shown in FIGS. 1 and 2, one of the two adjacent hard resin tubes 10 (on the right side in the figure) has a receptacle 12 for the hard resin tube 10A, and the other has a slot 13 for the hard resin tube 10B. These hard resin pipes 10A and 10B are connected by being inserted.
Hereinafter, the code of the tube body 11 of the one hard resin tube 10A will be referred to as "11A", and the code of the tube body 11 of the other hard resin tube 10B will be referred to as "11B", as appropriate. In the description, the socket 12 refers to the hard resin tube 10A, and the slot 13 refers to the hard resin tube 10B, unless otherwise specified.

As shown in FIG. 3, the receiving port 12 is provided with a seal member 14. Therefore, the hard resin pipe connection structure 1 is C-shaped. An annular sealing groove 12d is formed on the inner peripheral surface of the receiving port 12 on the rear side, that is, on the pipe body 11A side (right side in FIG. 3). The seal member 14 is fitted in the sealing annular groove 12d. The seal member 14 is made of rubber or the like and has an annular shape. The sealing member 14 projects from the inner peripheral surface of the receiving port 12 to the inside of the receiving port 12. The inner diameter of the seal member 14 in the natural state is substantially equal to or slightly smaller than the outer diameter of the insertion opening 13. As shown in FIG. 2, when the hard resin pipes 10 are connected to each other, the seal member 14 is brought into close contact with the entire circumference of the outer peripheral surface of the insertion opening 13, so that the space between the receiving opening 12 and the insertion opening 13 is sealed. Has been done.

As shown in FIG. 2, the hard resin pipe connection structure 1 is provided with means 15 for preventing separation of the hard resin pipes 10 from each other. The separation prevention means 15 includes a receiving side separation prevention member 20 and an insertion side separation prevention member 30. As illustrated in FIG. 3, the receiving side 12 is provided with the receiving side separation prevention member 20, and the insertion port 13 is provided with the insertion side separation prevention member 30. The separation prevention members 20 and 30 are separate from the hard resin tubes 10A and 10B. The separation preventing members 20 and 30 are made of a resin having appropriate elasticity and hardness, and at least one of them is more elastic than the hard resin pipe 10.
It should be noted that one of the separation preventing members 20 and 30 may be harder than the other, and may be of the same hardness as the hard resin pipe 10 or higher. For example, one of the separation prevention members 20 and 30 may be made of a hard resin such as FRP or FRPM, or may be made of a FRP laminated body.

The receiving side separation prevention member 20 includes a main body portion 21 and a flange 22. The main body 21 is separated from the sealing member 14 in the receiving port 12 to the tip side (the end side in the direction in which the insertion port 11 enters, that is, the side opposite to the pipe main body 11A, the left side in FIG. 2). Are arranged. The main body 21 has a cylindrical shape. The outer peripheral surface of the main body 21 is a straight cylindrical surface. The inner peripheral surface of the main body portion 21 has a taper shape in which the diameter is gradually reduced toward the inner side of the receiving port 12, that is, the tube main body portion 11A side (right side in FIG. 3). The thickness of the main body portion 21 increases toward the side of the pipe main body portion 11A.

A locking protrusion 23 is formed at an intermediate portion of the main body portion 21 in the tube axis direction. The locking projection 23 projects from the outer peripheral surface of the main body 21 and has an annular shape.
A fitting groove 12b is formed on the inner peripheral surface of the receiving port 12. The locking protrusion 23 is fitted in the fitting groove 12b.

An annular flange 22 is provided at the tip portion (left end portion in FIG. 3) of the main body portion 21. The flange 22 projects outward in the radial direction from the body portion 21. The flange 22 covers the front end surface 12e of the receiving port 12.

The receiving side separation prevention member 20 is bonded to the receiving port 12 via an adhesive (details not shown). As the adhesive, various adhesives such as an epoxy adhesive and a urethane adhesive can be applied. When the receiving side separation prevention member 20 is a FRP laminated body, it is preferable to sand the receiving opening 12 and then laminate.

As shown in FIG. 3, the insertion side detachment prevention member 30 is arranged on the outer peripheral surface of the pipe body 11B side (left side in FIG. 3) of the distal end portion 13e of the insertion port 13 to which the seal member 14 closely contacts. The insertion-side detachment prevention member 30 has an annular shape. The outer peripheral surface of the insertion-side detachment prevention member 30 is tapered so that its diameter decreases toward the tip portion 13e. That is, the thickness of the insertion-side detachment prevention member 30 decreases toward the tip portion 13e. The maximum outer diameter of the insertion-side detachment prevention member 30 (the outer diameter of the end portion on the tube body portion 11B side) is larger than the inner diameter of the receiving-side detachment prevention member 20.
The thickness of the insertion side detachment prevention member 30 may be constant over the entire length.

The insertion side detachment prevention member 30 and the insertion opening 13 are adhered to each other via an adhesive (details not shown). As the adhesive, the same adhesive as the adhesive between the receiving side separation preventing member 20 and the receiving port 12 can be applied. Instead of the adhesive or in addition to the adhesive, the insertion side detachment preventing member 30 and the insertion opening 13 may be fixed by a mechanical fixing means such as screwing. When the insertion-side detachment prevention member 30 is an FRP laminated body, it is preferable that the insertion opening 13 is sanded and then laminated.

As shown in FIG. 2, when the two hard resin pipes 10</b>A and 10</b>B are connected to each other, the main body portion 21 of the receiving-side removal prevention member 20 and the insertion-side removal prevention member 30 connect the receiving opening 12 and the insertion opening 13. It is arranged in the clearance between them. Moreover, the insertion-side removal prevention member 30 is arranged between the receiving-side removal prevention member 20 and the seal member 14. Preferably, the insertion-side detachment prevention member 30 is arranged farther from the seal member 14 toward the tip surface 12e side (left side in FIG. 2) of the receiving port 12 and is not in contact with the seal member 14.

<How to connect the hard resin tube 10>
The two hard resin tubes 10 are connected to each other as follows.
In advance, the receiving side separation prevention member 20 and the seal member 14 are installed in the receiving opening 12 of the one hard resin tube 10A, and the insertion side separation preventing member 30 is installed in the insertion opening 13 of the other hard resin tube 10B. Keep it.
As shown in FIG. 4A, the hard resin pipes 10 are aligned with each other and the insertion port 13 is inserted into the receiving port 12.
As shown in FIG. 4B, the separation preventing members 20 and 30 eventually come into contact with each other. Here, by applying a strong insertion force, the separation preventing members 20 and 30 are made to cross each other. By configuring at least one of the separation preventing members 20 and 30 with an elastic material, the one member can be elastically deformed, and the required insertion force can be reduced. The insertion-side detachment prevention member 30 has a tapered shape in which the diameter thereof decreases toward the tip portion 13e, so that the insertion-side removal prevention member 30 can be inserted more easily.
As shown in FIG. 4C, the insertion-side detachment prevention member 30 is positioned between the receiving-side detachment prevention member 20 and the seal member 14 due to the riding over. Further, a portion 13e of the insertion opening 13 on the tip side (right side in the figure) of the insertion-side detachment prevention member 30 is press-fitted into the seal member 14 to be in close contact therewith. This completes the connection operation between the hard resin pipes 10. It is not necessary for the insertion side detachment prevention member 30 to ride over the seal member 14. Therefore, the insertion force may be increased only when the insertion-side removal prevention member 30 gets over the receiving-side removal prevention member 20, and the work amount at the time of connection can be reduced. The sealing member 14 need only be applied with a load due to press-fitting of the insertion port 13, and damage to the sealing member 14 can be prevented or reduced.

As shown in FIG. 5, when the pull-out force F acts on the hard resin pipes 10A and 10B due to an earthquake or a rise in the pipe internal pressure, the hard resin pipes 10A and 10B are relatively displaced in the pull-out direction. The insertion-side removal prevention member 30 abuts on and is locked by the receiving-side removal prevention member 20. Further, the locking force can be increased by fitting the locking projection 23 and the fitting groove 12b. This can prevent the hard resin tubes 10A and 10B from coming off from each other.

Next, another embodiment of the present invention will be described. In the following embodiments, the same reference numerals will be given to the drawings for the configurations that are the same as the configurations described above, and the description thereof will be omitted.
<Second Embodiment>
As shown in FIG. 6, the second embodiment relates to a modification of the receiving side separation prevention member 20. In the main body portion 21 of the receiving side separation prevention member 20B of the second embodiment, in addition to the locking projection 23 at the middle portion, the locking projection 23B is formed at the end portion on the far side (right side in FIG. 5). There is. The locking projection 23B has an annular shape and is projected radially outward from the outer peripheral surface of the main body 21.

A fitting groove 12c is formed on the inner peripheral surface of the receiving port 12 in addition to the fitting groove 12b. The locking protrusion 23B is fitted in the fitting groove 12c.
According to the second embodiment, the engagement strength between the receiving side separation prevention member 20B and the receiving opening 12 and thus the engagement force against the removal force F (see FIG. 5) is fitted by only one engagement protrusion 23. Can be higher than the case (Fig. 2).

<Third Embodiment>
As shown in FIG. 7, the third embodiment relates to another modification of the receiving side separation prevention member 20. As shown in FIG. 7A, in the receiving side separation prevention member 20C of the third embodiment, the outer peripheral surface of the main body portion 21 expands toward the back side of the receiving port 12 (right side in FIG. 7A). It has a tapered shape that radiates. The thickness of the main body portion 21 increases toward the back side of the receiving port 12. The engagement protrusion 23 is not formed on the receiving side separation prevention member 20C.

The fitting groove 12b for the locking projection 23 is not formed on the inner peripheral surface of the receiving port 12. Instead of this, a tapered recess 12g is formed on the inner peripheral surface of the receiving port 12. The tapered recess 12g has a diameter that increases toward the back side. The tapered portion of the main body 21 is housed in the tapered recess 12g.

As shown in FIG. 7B, according to the third embodiment, when the hard resin pipes 10 are joined to each other, the pulling force F acts strongly, so that the receiving side detachment prevention member 20C and the receiving port 12 should be provided. Even if the adhesion between the receiving side and the receiving side is broken (two-dot chain line in the figure), the receiving side separation preventing member 20 does not come out from the receiving port 12. That is, in order for the tapered portion of the main body portion 21 to be relatively displaced toward the tip end side of the receiving opening 12 (left side in FIG. 7B), it is necessary to widen the clearance between the receiving opening 12 and the insertion opening 13. Almost impossible. As a result, it is possible to reliably prevent the hard resin tubes 10 from coming off from each other.

<Fourth Embodiment>
As shown in FIG. 8, the fourth embodiment relates to another modification of the receiving side separation prevention member 20. In the receiving side separation prevention member 20D of the fourth embodiment, the entire outer peripheral surface of the main body portion 21 is a smooth cylindrical surface having no unevenness. The engagement protrusion 23 is not formed on the receiving side separation prevention member 20D. The fitting groove 12b for the locking projection 23 is not formed in the receiving port 12. Accordingly, when the receiving side separation prevention member 20D and the receiving port 12 are bonded, the adhesive can be easily and evenly applied to the inner peripheral surface of the receiving port 12 or the outer peripheral surface of the main body portion 21. Therefore, the receiving side separation prevention member 20D and the receiving port 12 can be reliably joined.

<Fifth Embodiment>
9 and 10 show a fifth embodiment of the present invention. In the fifth embodiment, the receiving side separation prevention member 20E is attached to the receiving port 12 after the hard resin tubes 10 are fitted together. As shown in FIG. 9, before the hard resin pipes 10 are joined together, the receiving side separation prevention member 20E is separated from the receiving port 12. The receiving side separation prevention member 20E is made of an elastic body having appropriate elasticity and hardness, and is made of rubber having a hardness of 60° or more, for example.

The main body portion 21 of the receiving side separation prevention member 20E has a straight cylindrical shape. The locking projection 23 is not formed on the outer peripheral surface of the main body portion 21. The fitting groove 12b for the locking projection 23 is not formed on the inner peripheral surface of the receiving port 12. The outer diameter of the main body portion 21 in the natural state (before attachment to the receiving opening 12) may be equal to or larger than the inner diameter of the receiving opening 12. By doing so, the main body 21 can be brought into close contact with the inner peripheral surface of the receiving side 12 in the state where the receiving side separation preventing member 20E is mounted on the receiving side 12 (FIG. 10C).
As shown in FIG. 9, a tapered portion 12a is formed on the inner peripheral surface of the receiving end 12 on the front end side (left side in FIG. 9), the diameter of which increases toward the front end surface 12e.

<How to connect the hard resin pipe 10 of the fifth embodiment>
As shown in FIG. 9, when joining the hard resin pipes 10 to each other, the receiving side detachment prevention member 20E is disposed on the pipe body 11B side (in FIG. 9A) with respect to the insertion side detachment prevention member 30 of the insertion opening 13. Place it on the outer circumference (left side).
Next, as shown in FIG. 10A, the insertion opening 13 and thus the insertion side detachment prevention member 30 are inserted into the receiving opening 12. Since the insertion side detachment prevention member 30 has a smaller diameter than the inner diameter of the receiving port 12, it can be easily inserted without requiring a large insertion force. It is not necessary for the separation preventing members 20 and 30 to cross each other.
As shown in FIG. 10B, after the insertion opening 13 is inserted to a predetermined joining position in the receiving opening 12 (the position where the tip portion 13e is in close contact with the seal member 14), the main body portion of the receiving side separation preventing member 20E. 21 is inserted into the socket 12. When the outer diameter of the main body portion 21 is larger than the inner diameter of the receiving port 12, the main body portion 21 is press-fitted, but when the separation preventing members 20 and 30 pass over each other (FIG. 4B, etc.) Compared with, the insertion force can be significantly reduced. Since the inner periphery of the tip of the receiving port 12 is the tapered portion 12a, the receiving side separation preventing member 20E can be inserted more easily. A hitting jig or the like may be used for press fitting. An adhesive (detailed illustration is omitted) is preferably applied between the receiving side separation prevention member 20E and the receiving port 12. Since the outer peripheral surface of the main body portion 21 of the receiving side separation prevention member 20E and the inner peripheral surface of the receiving port 12 are cylindrical surfaces having no unevenness, the adhesive can be easily and evenly applied.
As shown in FIG. 10C, the receiving side separation prevention member 20E is inserted into the receiving opening 12 until the flange 22 abuts on the tip surface 12e, and then cured until the adhesive is hardened.
The insertion side detachment preventing member 30 is located between the receiving side detachment preventing member 20E and the seal member 14 as in the first embodiment (FIG. 2) and the like. Therefore, damage to the seal member 14 can be prevented or reduced.

<Sixth Embodiment>
11 and 12 show a sixth embodiment of the present invention. The sixth embodiment relates to a modification of the fifth embodiment (FIGS. 9 to 10) in which a receiving side separation prevention member is retrofitted. As shown in FIG. 11, a locking projection 23 is formed on the main body portion 21 of the receiving side separation prevention member 20F of the sixth embodiment. The receiving opening 12 is formed with a fitting groove 12b for the locking projection 23.

<How to connect the hard resin pipe 10 of the sixth embodiment>
As shown in FIG. 12, the procedure for connecting the hard resin tubes 10 to each other is the same as that in the fifth embodiment (FIG. 10). That is, as shown in FIG. 12A, the receiving-side removal prevention member 20F is arranged on the outer circumference of the pipe body 11B side (left side in FIG. 12A) of the insertion-side removal prevention member 30 of the insertion opening 13. After that, the insertion opening 13 and thus the insertion side detachment prevention member 30 are inserted into the receiving opening 12. Subsequently, as shown in FIG. 12B, the main body portion 21 of the receiving side separation prevention member 20F is inserted into the receiving port 12. At this time, the locking projection 23 is press-fitted because it interferes with the receiving port 12, but compared with the case where the separation preventing members 20 and 30 are crossed over each other (FIG. 4B, etc.), the insertion force is increased. Can be reduced. By providing the tapered portion 12a on the inner circumference of the tip end portion of the receiving port 12, the locking projection 23 of the receiving side separation prevention member 20F can be inserted more easily. A hitting jig or the like may be used for press fitting. An adhesive (detailed illustration is omitted) is preferably applied between the receiving side separation prevention member 20F and the receiving port 12.
When the receiving side separation prevention member 20F is press-fitted into the receiving opening 12, as shown in FIG. 12C, the locking projection 23 is fitted into the fitting groove 12b. Thereby, the receiving side separation prevention member 20F can be positioned with respect to the receiving port 12. In addition, the joint strength between the receiving side separation prevention member 20B and the receiving port 12 can be increased. Furthermore, when the pull-out force F (see FIG. 5) acts, a locking force that resists this can be secured.

<Seventh Embodiment>
13 and 14 show a seventh embodiment of the present invention. The seventh embodiment relates to a modification of the fifth embodiment (FIGS. 9 to 10) in which a receiving side separation prevention member is retrofitted. As shown in FIG. 13, the receiving side separation prevention member 20G of the seventh embodiment is made of metal (hard material), but may be made of hard resin such as FRP or FRPM.

The outer peripheral surface of the main body 21 of the receiving side separation prevention member 20G has a gentle taper shape whose diameter increases toward the flange 22.
The tip side portion (the portion where the receiving side separation prevention member 20G is arranged) on the inner peripheral surface of the receiving port 12 is a gentle taper surface 12f that increases in diameter toward the tip surface 12e in accordance with the main body portion 21. Has become.

<How to connect the hard resin pipe 10 of the seventh embodiment>
As shown in FIG. 14, the procedure for connecting the hard resin tubes 10 to each other is almost the same as that in the fifth embodiment (FIG. 10).
As shown in FIG. 14B, when the receiving side separation prevention member 20G is inserted into the receiving port 12, it is not necessary to press-fit the receiving side separation prevention member 20G. Therefore, the insertion force can be further reduced.
Although detailed illustration is omitted in FIG. 14C, the receiving side separation prevention member 20G and the receiving port 12 are bonded by an adhesive. A void-filling adhesive may be used as the adhesive.
According to the seventh embodiment, even if the receiving-side separation prevention member 20G is made of a hard material such as metal or hard resin, the tapered outer peripheral surface of the main body portion 21 is surely attached to the tapered surface 12f of the receiving port 12. Can be closely attached. It is not necessary to set the clearance between the outer peripheral surface of the main body portion 21 of the receiving side separation prevention member 20G and the inner peripheral surface of the receiving port 12 with high accuracy.

<Eighth Embodiment>
15 and 16 show an eighth embodiment of the present invention. The eighth embodiment relates to another modification of the fifth embodiment (FIGS. 9 to 10) in which the receiving side separation prevention member is retrofitted. As shown in FIG. 15, the receiving-side detachment prevention member 20H of the eighth embodiment is annular (C-shaped) having a notch 25 at one location in the circumferential direction.

The receiving side separation prevention member 20H is made of a metal (hard material) such as iron, steel, and stainless steel, and preferably spring steel. The receiving side separation prevention member 20H may be made of FRP or other hard resin instead of metal.
The receiving side separation prevention member 20H can be expanded/contracted by applying an expanding or contracting force. The outer diameter of the main body portion 21 of the receiving side separation prevention member 20H in the natural state (the unloaded state in which the expanding force or the reducing force is not applied) may be equal to or larger than the inner diameter of the receiving port 12.

A locking projection 23 is formed on the outer peripheral surface of the main body 21 of the receiving side separation prevention member 20H.
As shown in FIG. 16B, a fitting groove 12b for the locking projection 23 is formed on the inner peripheral surface of the receiving port 12.

<How to connect the hard resin pipe 10 of the eighth embodiment>
As shown in FIG. 16A, when the hard resin pipes 10 are connected to each other, the receiving side separation prevention member 20H is arranged on the outer periphery of the insertion opening 13. At this time, as shown by the chain double-dashed line in the figure, by expanding the diameter of the receiving side separation prevention member 20H, the receiving side separation prevention member 20H can easily get over the insertion side separation prevention member 30. As a result, as shown by the solid line in the figure, the receiving side separation prevention member 20H can be easily attached to the outer periphery of the pipe body 11B side (left side in FIG. 16A) of the insertion side separation prevention member 30 of the insertion port 13. Can be placed at.
Next, as shown in FIG. 16B, the insertion opening 13 is inserted into the receiving opening 12, and subsequently, the main body portion 21 of the receiving side separation prevention member 20H is inserted into the receiving opening 12. At this time, the receiving side separation prevention member 20H is reduced in diameter. Thereby, the insertion operation of the main body portion 21 can be easily performed. The locking projection 23 needs to be press-fitted in order to interfere with the receiving port 12, but the required press-fitting force can be reduced by the diameter reduction. By providing the tapered portion 12a on the inner circumference of the tip end portion of the receiving port 12, the locking projection 23 of the receiving side separation preventing member 20H can be inserted more easily.

As shown in FIG. 16C, after the receiving side separation prevention member 20H is inserted into the receiving opening 12 until the flange 22 abuts the tip end surface 12e and the locking projection 23 is aligned with the fitting groove 12b, The reduced diameter of the side separation prevention member 20H is released. As a result, the receiving side separation prevention member 20H is expanded in diameter, the main body portion 21 strongly abuts the inner peripheral surface of the receiving opening 12, the locking projection 23 fits into the fitting groove 12b, and the receiving side separation prevention member 20H moves. It is prevented from coming off from the receptacle 12.
The insertion side detachment prevention member 30 is located between the receiving side detachment prevention member 20H and the seal member 14 as in the first embodiment (FIG. 2) and the like, and prevents damage to the seal member 14 or It can be reduced.

The receiving side separation prevention member 20H is attachable to and detachable from the receiving port 12 even after the connection between the hard resin pipes 10 is completed. That is, when the connection is defective, the receiving side separation preventing member 20H can be removed from the receiving port 12 by reducing the diameter of the receiving side separation preventing member 20H. As a result, the hard resin tubes 10 can be separated. Therefore, the connection construction can be redone.

<Ninth Embodiment>
17 to 20 show a ninth embodiment of the present invention. As shown in FIG. 17, a rim 12h is formed at the tip of the receptacle 12. The rim 12h has an annular shape and projects radially inward of the receptacle 12. The rim 12h constitutes a receiving side separation prevention member. That is, in the ninth embodiment, the receiving side separation prevention member 12h has an integral structure with the receiving port 12. As shown in FIG. 19B, the inner diameter of the rim 12h is substantially the same as or larger than the outer diameter of the insertion side detachment preventing member 30.

As shown in FIG. 17, an annular ring accommodating recess 12k is formed on the inner peripheral surface of the receiving port 12. The ring housing recess 12k is arranged adjacent to the inner side (right side in FIG. 17) of the rim 12h. A stepped stopper portion 12s is formed between the ring housing recess 12k and the rim 12h.

As shown in FIG. 17, the separation prevention means 16 of the ninth embodiment includes a locking ring 40 and an expansion/contraction operation unit 50 in addition to the rim 12h as the receiving side separation prevention member and the insertion side separation prevention member 30. I have it. As shown in FIG. 18, the locking ring 40 is formed in an annular shape (C-shape) having a ring cutout 45 at one position in the circumferential direction, and is expandable/contractible. As shown in FIG. 18A, when the locking ring 40 is in a natural state, both ends of the ring notch 45 are in contact with or close to each other, and the diameter of the locking ring 40 is almost minimum. It has become. As shown in FIG. 18B, the locking ring 40 is expanded by expanding the ring cutout 45.

The material of the locking ring 40 is made of a metal (hard material) such as iron, steel, and stainless steel, and preferably spring steel. The locking ring 40 may be made of FRP or other hard resin instead of metal.
The FRP locking ring 40 may be manufactured by cutting the FRP tube to an appropriate length and making a notch at one position in the circumferential direction.

As shown in FIG. 20A, the locking ring 40 is housed in the ring housing recess 12k. When the hard resin pipes 10 are connected to each other, a locking ring 40 is interposed between the rim 12h (reception side separation prevention member) and the insertion side separation prevention member 30.

As shown in FIGS. 17 and 21, the receptacle 12 is provided with a scaling operation unit 50. The expansion/contraction operation unit 50 is for operating the locking ring 40 between the expanded diameter state and the reduced diameter state. Specifically, the expansion/contraction operation unit 50 includes a window 51 and a diameter expansion piece 52. The window portion 51 is arranged at one position in the circumferential direction of the portion of the receptacle 12 that constitutes the ring-accommodating recess 12k, and is a square hole. The window portion 51 penetrates the receptacle 12 in the thickness direction or the radial direction.

As shown in FIG. 17, the expanded diameter piece 52 is arranged in the window portion 51. The diameter expansion piece 52 is formed in the shape of a rectangular small piece. As shown in FIG. 21( a ), both end surfaces of the enlarged diameter piece 52 as viewed from the axial direction of the receiving port 12 are directed toward the inner side of the receiving port 12 in the radial direction (left side in FIG. 21( a )). It is slanted so that the intervals are narrow. As shown in FIGS. 21( a) and 21 (b ), the expanded diameter piece 52 can be inserted into and taken out of the window portion 51. In addition, the expanded diameter piece 52 can be fitted into and removed from the ring cutout portion 45 of the locking ring 40 in a state of being put into the window portion 51.

As shown in FIGS. 17 and 21(a), when the expanded diameter piece 52 is fitted in the ring cutout 45, the ring cutout 45 is expanded and the locking ring 40 is expanded. As shown in FIGS. 19(a) to 19(c), the locking ring 40 in the expanded diameter state is locked in the receiving port 12 when the outer peripheral surface thereof is brought into contact with or close to the inner bottom surface of the ring housing recess 12k. Has been done. As shown in FIG. 19B, the inner diameter of the locking ring 40 in the expanded state is larger than the outer diameter of the insertion-side detachment prevention member 30.

As shown in FIGS. 20(a) and 21(b), when the hard resin pipes 10 are connected to each other, the locking ring 40 is reduced in diameter when the expanded diameter piece 52 is removed from the ring cutout 45. And is pressed against the insertion slot 13. As a result, the locking ring 40 is fixed to the insertion slot 13. As shown in FIG. 20(a), the outer diameter of the locking ring 40 in the reduced diameter state is larger than the inner diameter of the rim 12h and is deeper (right side in the figure) than the ring housing recess 12k. Larger than the inner diameter of. Therefore, when the hard resin pipes 10 are connected to each other, the locking ring 40 is prevented from coming out of the ring housing recess 12k. The insertion side detachment prevention member 30 is located between the rim 12h (reception side detachment prevention member) and the seal member 14 as in the first embodiment (FIG. 2) and the like, and the seal member 14 is damaged. Can be prevented or reduced.

<How to connect the hard resin pipe 10 of the ninth embodiment>
As shown in FIG. 17, when the hard resin pipes 10 are connected to each other, the expanding ring 52 is fitted into the ring cutout 45 to bring the locking ring 40 into the expanded state.
Then, as shown in FIG. 19A, the insertion opening 13 is inserted into the receiving opening 12. As shown in FIG. 19B, since “inner diameter of the rim 12h≧outer diameter of the insertion-side removal prevention member 30”, the insertion-side removal prevention member 30 does not interfere with the rim 12h and Easily inserted into. Furthermore, since “the inner diameter of the locking ring 40 in the expanded state≧the outer diameter of the insertion-side removal prevention member 30”, the insertion-side removal prevention member 30 does not interfere with the locking ring 40 and the locking ring 40 It is more easily transferred to the back side of the receiving port 12. As a result, as shown in FIG. 19C, the insertion opening 13 can be easily inserted to a predetermined joining position in the receiving opening 12, and the required insertion force can be greatly reduced.

Next, as shown in FIGS. 20(a) and 21(b), the expansion ring piece 52 is removed from the ring cutout portion 45 through the window portion 51 so that the locking ring 40 is reduced in diameter and inserted. It is fixed on the outer peripheral surface of the mouth 13. This completes the connection operation between the hard resin pipes 10.
When there is a problem in connection, the diameter of the locking ring 40 is expanded by inserting the diameter expansion piece 52 into the window portion 51 and fitting it into the ring cutout portion 45 again. As a result, the hard resin pipes 10 can be separated from each other, and the connection construction can be redone.
At the end of the connection construction, the window 51 is covered with a window cover (not shown). This can prevent dirt and the like from entering the hard resin tube 10 through the window 51.

As shown in FIG. 20( b ), when the hard resin pipes 10 are relatively displaced in the pulling-out direction by the action of the pulling force F, the insertion side separation prevention member 30 abuts on the locking ring 40 and the locking ring. 40 hits the stopper portion 12s of the rim 12h. That is, the rim 12h (receiving side separation prevention member) and the insertion side separation prevention member 30 are locked to each other via the locking ring 40. As a result, it is possible to prevent the hard resin tubes 10 from coming off from each other.

<Tenth Embodiment>
As shown in FIG. 22, the tenth embodiment relates to a modification of the window portion 51. The window portion 51 of the tenth embodiment reaches the tip end surface 12e of the receiving port 12 and has a notch shape.
According to the tenth embodiment, the expanded diameter piece 52 can be easily attached to and detached from the ring cutout 45 through the window 51. As a result, the locking ring 40 can be easily expanded and contracted.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the number of the locking projections 23 of the receiving side separation prevention member 20 is not limited to one (FIG. 2) or two (FIG. 6), and may be three or more.
Multiple embodiments may be combined with each other. For example, the cross-sectional shape of the receiving-side separation prevention member 20H of FIG. 16 may be modified to the cross-sectional shape of the receiving-side separation prevention member 20 of another embodiment. The post-removal receiving side separation prevention member 20H may be inserted into the receiving port 12 and then bonded with an adhesive.

The present invention can be applied to, for example, a joint structure for a sewer pipe or an agricultural water pipe.

1 Hard Resin Pipe Connection Structure 10 Hard Resin Pipe 10A One Hard Resin Pipe 10B Other Hard Resin Pipe 12 Receptacles 12b, 12c Fitting Groove 12g Tapered Recess 12h Rim (Receiving Side Detachment Prevention Member)
13 Insertion Port 14 Annular Seal Member 20 Receiving Side Separation Prevention Members 20B to 20H Receiving Side Separation Prevention Members 23, 23B Locking Protrusion 25 Notch 30 Insertion Side Disengagement Preventing Member 40 Locking Ring 45 Ring Notch 50 Expansion/contraction Operating Portion 51 Window Part 52 Expanded piece

Claims (12)

One hard resin pipe having a receiving port, and a hard resin pipe connection structure consisting of the other hard resin pipe having an insertion port inserted into the receiving port,
An annular seal member provided on the inner peripheral surface of the receiving opening and sealing between the outer peripheral surface of the insertion opening,
A receiving side separation preventing member provided on the inner peripheral surface of the receiving port at the tip side of the receiving port with respect to the sealing member;
An insertion side separation prevention member provided on the outer peripheral surface of the insertion opening, wherein the insertion side separation prevention member in the connection state of the hard resin pipes is between the receiving side separation prevention member and the seal member. And a receiving-side detachment preventing member is formed in a thin-walled cylindrical shape whose inner peripheral surface is reduced in diameter toward the seal member to increase the thickness, and is disposed on the inner peripheral surface of the receiving port. the have the挿側separation preventing member is rigid resin pipe connection structure, wherein the thin cylindrical der Rukoto the thickness smaller outer peripheral surface toward the tip end side of the spigot is reduced in diameter. One hard resin pipe having a receiving port, and a hard resin pipe connection structure consisting of the other hard resin pipe having an insertion port inserted into the receiving port,
An annular seal member provided on the inner peripheral surface of the receiving opening and sealing between the outer peripheral surface of the insertion opening,
A receiving side separation preventing member provided on the inner peripheral surface of the receiving port on the tip side of the sealing member,
An insertion side separation prevention member provided on the outer peripheral surface of the insertion opening, wherein the insertion side separation prevention member in the connection state of the hard resin pipes is between the receiving side separation prevention member and the seal member. Placed in
The receiving-side separation preventing member, the receptacle and glued, or bondable der is, and the receiving-side separation preventing member, the main body portion of the thin-walled cylindrical outer peripheral surface toward said seal member has a reduced diameter has a outer peripheral surface and the portion to be bonded of the body portion of the inner peripheral surface of the socket is tapered der Rukoto which diametrically enlarged toward the front end surface of the socket reaches the front end surface Characteristic hard resin pipe connection structure. The hard resin pipe according to claim 1 or 2 , wherein the entire outer peripheral surface of the main body portion arranged on the inner peripheral surface of the receiving port of the receiving side separation prevention member has a smooth cylindrical surface shape. Connection structure. The inner peripheral surface of the receiving port is formed with a tapered recessed portion that expands in diameter toward the back side,
The outer peripheral surface of the main body portion , which is arranged on the inner peripheral surface of the receiving opening in the receiving side separation prevention member, has a tapered shape in which the diameter increases toward the rear side,
The hard resin pipe connection structure according to claim 1 or 2 , wherein the receiving side separation preventing member is housed in the tapered recess. One hard resin pipe having a receiving port, and a hard resin pipe connection structure consisting of the other hard resin pipe having an insertion port inserted into the receiving port,
An annular seal member provided on the inner peripheral surface of the receiving opening and sealing between the outer peripheral surface of the insertion opening,
A receiving side separation preventing member provided on the inner peripheral surface of the receiving port on the tip side of the sealing member,
An insertion side separation prevention member provided on the outer peripheral surface of the insertion opening, wherein the insertion side separation prevention member in the connection state of the hard resin pipes is between the receiving side separation prevention member and the seal member. Placed in
The inner peripheral surface of the socket has a fitting groove and a tapered portion which increases in diameter toward the distal end surface of the socket is provided from the fitting groove on the tip side is formed,
The receiving-side detachment preventing member is formed with an annular locking projection that is fitted into the fitting groove, and the intersection of the tip end surface of the receiving port and the tapered portion is the outer peripheral surface of the locking projection. hard resin pipe connection structure, wherein larger diameter der Rukoto. One hard resin pipe having a receiving port, and a hard resin pipe connection structure consisting of the other hard resin pipe having an insertion port inserted into the receiving port,
An annular seal member provided on the inner peripheral surface of the receiving opening and sealing between the outer peripheral surface of the insertion opening,
A receiving side separation preventing member provided on the inner peripheral surface of the receiving port on the tip side of the sealing member,
An insertion side separation prevention member provided on the outer peripheral surface of the insertion opening, wherein the insertion side separation prevention member in the connection state of the hard resin pipes is between the receiving side separation prevention member and the seal member. Placed in
Furthermore, an annular ring having a ring notch portion at one location in the circumferential direction, and a locking ring interposed between the receiving side separation prevention member and the insertion side separation prevention member in the connected state,
An expansion/contraction operation unit that is provided in the receiving opening and is operable to operate the locking ring between an expanded diameter state and a reduced diameter state,
In the expanded diameter state, the locking ring is locked in the receiving port, and the inner diameter of the locking ring is larger than the outer diameter of the insertion side detachment prevention member,
In the reduced diameter state, the locking ring is pressed against the insertion opening, and the outer diameter of the locking ring is larger than the inner diameter of the receiving side separation prevention member,
The scaling operation unit, and the window portion formed in the socket, viewed contains a lump diameter piece of square can be fitted into and out possible and the ring notch from the window, of the receiving opening A hard resin pipe connection structure characterized in that both end surfaces of the diameter-expanding piece as viewed from the axial direction are inclined so that the distance between them becomes narrower toward the inner side in the radial direction of the receptacle . One hard resin pipe having a receiving port, and a hard resin pipe connection structure consisting of the other hard resin pipe having an insertion port inserted into the receiving port,
An annular seal member provided on the inner peripheral surface of the receiving opening and sealing between the outer peripheral surface of the insertion opening,
A receiving side separation preventing member provided on the inner peripheral surface of the receiving port on the tip side of the sealing member,
An insertion side separation prevention member provided on the outer peripheral surface of the insertion opening, wherein the insertion side separation prevention member in the connection state of the hard resin pipes is between the receiving side separation prevention member and the seal member. Placed in
Furthermore, an annular ring having a ring notch portion at one location in the circumferential direction, and a locking ring interposed between the receiving side separation prevention member and the insertion side separation prevention member in the connected state,
An expansion/contraction operation unit that is provided in the receiving opening and is operable to operate the locking ring between an expanded diameter state and a reduced diameter state,
In the expanded diameter state, the locking ring is locked in the receiving port, and the inner diameter of the locking ring is larger than the outer diameter of the insertion side detachment prevention member,
In the reduced diameter state, the locking ring is pressed against the insertion opening, and the outer diameter of the locking ring is larger than the inner diameter of the receiving side separation prevention member,
The expansion/contraction operation unit includes a window portion formed in the receiving port, and an expansion piece that can be inserted into and removed from the window portion and can be fitted into the ring cutout portion, and the expansion piece can be inserted into the window portion. A hard resin pipe connection structure characterized in that it does not stick out from the outer peripheral surface of the receiving port while being fitted into the ring cutout portion. At least one of the said receiving side detachment prevention member and the said insertion side detachment prevention member is richer in elasticity than the said hard resin pipe, The hard resin pipe connection in any one of Claims 1-8 characterized by the above-mentioned. Construction. Hard resin tube connection structure according to any one of claims 1-8, wherein the receiving-side separation preventing member, characterized in that it is detachable from the receptacle. The hard resin pipe connection structure according to any one of claims 1 to 9 , wherein the receiving-side separation prevention member is expandable and contractable in an annular shape having a notch portion at one position in the circumferential direction. A method for connecting the hard resin pipes according to any one of claims 1 to 9 ,
The receiving-side detachment preventing member is removed from the receiving port, and the receiving-side detaching preventing member is arranged in the outer periphery on the inner side of the insertion port with respect to the insertion-side detaching preventing member. The insertion side separation prevention member of the mouth and the outer peripheral surface of the insertion opening is inserted, and an adhesive is applied to the outer peripheral surface of the receiving side separation prevention member .
After that, the receiving side separation prevention member is inserted into the receiving port and adhered to the inner peripheral surface of the receiving port , and the receiving side separation prevention member is attached to the receiving port. .. A method of connecting one hard resin pipe having a receiving port, and the other hard resin pipe having an insertion port inserted into the receiving port,
An annular seal member that seals between the inner peripheral surface of the receiving opening and the outer peripheral surface of the insertion opening is provided, and the inner peripheral surface of the receiving opening closer to the front end than the sealing member has a receiving side. A detachment prevention member is provided, an insertion side detachment prevention member is provided on the outer peripheral surface of the insertion opening, and the insertion side detachment prevention member when the hard resin pipes are connected to each other is the receiving side detachment prevention member and the seal. The receiving side separation preventing member, which is arranged between the member and the member, is expandable and contractable in an annular shape having a notch portion at one position in the circumferential direction,
The receiving side separation prevention member is expanded in diameter, fitted to the outer periphery of the insertion opening, and is positioned farther to the insertion side than the insertion side separation prevention member,
Next, the insertion opening is inserted into the receiving opening, and subsequently the receiving side separation preventing member is reduced in diameter and inserted into the receiving opening,
Next, by releasing the reduced diameter of the receiving side separation prevention member, the receiving side separation prevention member is brought into pressure contact with the inner surface of the receiving port.

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