JP2590383B2 - Plastic pipe fittings - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic pipe joint, and to an improvement in a plastic pipe joint.

[Conventional technology]

2. Description of the Related Art As a conventional plastic pipe fitting, a plastic fitting having a structure in which an insertion port is inserted into a receiving port and a rubber ring is inserted between the outer surface of the receiving port and the inner surface of the receiving port to seal the plastic pipe is known.

This type of pipe joint has the advantage that the connecting operation is easy and that there is a certain degree of freedom and tolerance even if an external force is applied to the connected pipe in the axial direction or the bending direction.

However, in the case of the above-mentioned type of pipe joint, when an external force is applied in the direction in which the pipe comes out, the insertion port may come out of the receiving port.

As a measure to prevent this escape, for example, as disclosed in Japanese Patent Publication No. 55-25317, the inner surface of the receiving port is formed in a tapered shape with a diameter decreasing toward the opening direction, and a wedge-like shape is formed between the outer surface of the receiving port and the inner surface of the receiving port. A pipe joint that prevents slipping out by utilizing the tightening force of the above gripping ring, which is deformed to reduce its diameter along the tapered surface of the inner surface of the receiving port when the pulling force is applied by inserting the gripping ring. As disclosed in JP-A-63-64993, in addition to the groove for mounting the rubber ring, a groove for mounting a reinforcing material having a groove for mounting a lock ring on the inner surface is provided at the opening end of the receiving port, and the reinforcing material is mounted. A pipe joint or the like in which a reinforcing material containing a lock ring is housed in a groove and a lock ring on the inner surface of the reinforcing material bites around the insertion opening to prevent escape when a withdrawal force acts on a connected pipe has been proposed. .

[Problems of the prior art]

However, the former one of the escape prevention structures is
There is no problem if the material strength of the socket is sufficient, but in the case of a plastic pipe joint, especially a socket obtained by expanding and deforming a straight pipe by secondary molding, the strength is insufficient and it can not be applied safely. There was a problem.

In other words, when the receiving port is formed by secondary molding, the receiving port is formed by expanding and deforming the original pipe, so that the wall thickness becomes thinner in accordance with the expansion ratio, and particularly, the opening of the receiving port is most expanded. Therefore, when the wedge-shaped gripping ring is pressed against the inner surface of the receiving port according to the pull-out force, plastic deformation or fracture cracking may occur without being able to withstand the radial pressure. Was.

However, in order to solve such difficulties, it is conceivable to fit a reinforcing ring on the outer surface of the receiving port so as to be able to withstand such an expanding pressure. However, it is very difficult and impossible to fit the reinforcing ring without any gap since the outer surface is not completely dimensioned even if it can be restricted.

In the latter, the reinforcing member protects the inner surface of the receiving port so that it does not have the drawbacks of the former, but the mounting groove for the reinforcing material is formed separately from the rubber ring mounting groove at the opening end of the receiving port. The disadvantage is that the mold is complicated and expensive,
Furthermore, in the case of a method of forming a receiving port by secondary forming a straight pipe,
There is a drawback that the deformation history of the plastic tube press-fitted into the mold becomes too long, making molding very difficult or impossible.

In addition, since the rubber ring mounting groove and the mounting groove for the reinforcing material are separated in the axial direction, there is a disadvantage that there is no degree of freedom in bending when a bending force acts on the insertion opening, and there is almost no tolerance to external force.

[Problems to be solved by the invention]

SUMMARY OF THE INVENTION In view of the above problems, the present invention can easily integrate a reinforcing annular member without requiring a mounting groove, and can withstand a slip-out preventing force, even in a receiving port formed by enlarging a plastic pipe and performing secondary molding. The purpose of the present invention is to make the structure possible.

[Technology that solved the problem]

That is, the plastic fitting of the present invention is a fitting in which a plastic pipe insertion port is received, and an enlarged-diameter receiving portion having a rubber ring mounting groove on the inner surface near the open end is formed by secondary molding of the plastic pipe. On a straight tubular receiving inner wall extending from the receiving opening opening end to the rubber ring mounting groove, a reinforcing annular body having an annular groove whose inner surface has a radial cross section whose bottom surface is tapered and shallower in the opening end direction than the back, It is characterized in that it is fitted into the rubber ring mounting groove at the time of the secondary molding of the plastic tube and is integrally fitted thereto. The groove extends along the inner wall of the recess.

〔Example〕

 Next, an embodiment of the present invention will be described.

FIG. 1 is a sectional view of an embodiment of the first invention, and FIG. 2 is a sectional view showing a use state of the embodiment of the second invention.

The plastic pipe fitting 1 of the present invention is a pipe fitting 1 which receives a plastic pipe insertion opening A and has a large-diameter receiving portion 1 ′ in which a rubber ring mounting groove 3 is formed on the inner surface near the open end 2. Reinforcing annular body having an outer surface 4A along the inner wall of the receiving port 1 'from the open end 2 and an annular groove 5 on the inner surface 4B having a radial cross section whose bottom surface 5A is tapered in the direction of the open end from the depth toward the open end. As shown in FIG. 1, a contact hole 4 is formed so as to be in contact with the rubber ring mounting groove 3 and to be integrally formed along the inner wall of the opening end of the receiving port 1 'during the secondary molding of the plastic pipe.

In the above, the reinforcing annular member 4 can be formed by fitting the rear end 4A 'along the concave inner wall 3A of the rubber ring mounting groove 3 as shown in FIG.

The plastic pipe fitting 1 is formed by the steps shown in FIG.

That is, when the pipe end C of the plastic pipe B is heated to the plasticizing temperature, and the heated end C is forcibly pushed into the die D to form the receiving port (FIGS. 3 and 4), the diameter is increased. The reinforcing annular body 4 is set coaxially with the rubber ring molding enlarged diameter portion E of the mold D, and a plasticized plastic tube C is mounted thereon and molded.

Therefore, after that, the reinforcing annular body 4 is firmly fixed by the diameter reduction deformation of the plastic tube accompanying the cooling.

After that, if the diameter-enlarged mold D is reduced in diameter and pulled out, as shown in FIG.
Are fitted together.

In the above embodiment, the case where the rear end 4A 'of the reinforcing annular member 4 is fitted along the concave inner wall 3A of the rubber ring mounting groove 3 is shown, but the embodiment shown in FIG. It goes without saying that it can be molded.

[Action]

When a pipe is joined by the plastic pipe joint 1 of the present invention, as shown in FIG. 6, a plastic pipe insertion port A is inserted in a state where a C-shaped ring 6 having a substantially circular cross section is inserted into an annular groove 5. Insert

At this time, the inner bottom surface 5A of the annular groove 5 moves toward the deeper portion as it goes deeper, and does not hinder the insertion of the insertion opening A.

When the external force is applied in the pipe axis direction after the pipes are joined, the C-shaped ring 6 is inserted into the annular groove 5 in the direction toward the open end.
With the tapered inner bottom surface 5A, and at the same time, the contact pressure with the tapered inner bottom surface 5A is increased to exhibit resistance.

In addition, a radial component force is applied to the outer surface of the receiving port along with the resistance, but a drag is exerted by the reinforcing annular body 4 to prevent deformation and breakage. Since the reinforcing annular body 4 is tightly fitted and integrally fitted to the inner wall of the receptacle, it does not come off.

Further, since the reinforcing annular member 4 and the rubber ring mounting groove 3 are provided in contact with each other, even if a bending force acts on the plastic tube insertion opening A, a certain degree of bending is possible.

As shown in FIG. 2, when the rear end 4 ′ of the reinforcing ring 4 is fitted along the concave inner wall 3 </ b> A of the rubber ring mounting groove 3, the reinforcing ring 4 itself has a stronger force to prevent the slipping out. It is convenient.

〔effect〕

As described above, the pipe joint according to the present invention is configured such that, when the slip-out prevention is performed, the portion where the radial external force applied by the retaining ring acts is constituted by the reinforcing ring.
Even in the case of plastic pipe joints, especially in the case of a plastic pipe socket formed in a secondary molding, the pipe ends are remarkably reinforced and can sufficiently withstand even a little large pull-out force. Since there is no need to provide the storage grooves independently, it is possible to easily mold even in the case of secondary molding of a plastic tube.

Furthermore, since the reinforcing annular member 4 is provided in contact with the rubber ring mounting groove 3, even if a bending force acts on the connected opening and receiving port, it can bend to some extent while maintaining watertightness, and the degree of freedom against external force And has an acceptable effect.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an embodiment of the first invention, FIG. 2 is a cross-sectional view of an embodiment of the second invention, FIGS. FIG. 6 is an explanatory view of a use state of the embodiment. 1 ... Plastic fitting, 1 '... Expansion port, 2 ...
... Open end, 3 ... Rubber ring mounting groove, 3A ... Recessed inner wall of rubber ring mounting groove, 4 ... Reinforcement annular body, 4A ... Reinforcement annular body outer surface, 4A '... Reinforcement annular body Ends, 4B: Reinforced annular inner surface, 5: Annular groove, 5A: Annular groove inner surface, A: Plastic pipe insertion port, B: Plastic pipe, C: Plastic pipe B pipe end.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kazutaka Takada 64, Ishizukita-cho, Sakai-shi, Osaka Inside Kubota-vinyl Pipe Factory (56) References Japanese Utility Model 1988-63 (JP, U)

Claims (2)

(57) [Claims] 1. A pipe joint for receiving a plastic pipe insertion opening and having a rubber ring mounting groove on the inner surface near the opening end formed by secondary molding of the plastic pipe. On the inner wall of the straight tubular port leading to the rubber ring mounting groove, a reinforcing annular body having an annular groove whose inner surface has a tapered bottom surface in the radial direction in the direction of the opening end from the back is formed in the rubber ring mounting groove. A plastic pipe joint which is integrally fitted in contact with the plastic pipe during secondary molding of the plastic pipe. 2. The plastic pipe joint according to claim 1, wherein a rear end of the reinforcing annular body extends along an inner wall of the recessed portion of the rubber ring mounting groove.