JPH04107389A - Plastic pipe coupling - Google Patents

Abstract

PURPOSE:To facilitate molding of a socket and to prevent the occurrence of slip off by axially continuously and integrally forming an annular groove which is shallower in a tapered manner from the inner wall on the open side of a rubber ring mounting groove in the direction of an open end, mounting a rubber ring for seal in the rubber ring mounting groove, and inserting a C-shaped ring for preventing slip-off in a manner that size is capable of being reduced. CONSTITUTION:In a plastic pipe coupling 1, an annular groove 4 being shallower in a tapered manner from an inner wall 3A on the open end side of a rubber ring mounting groove 3 in the direction of an open end 2 is axially continuously and integrally formed in the rubber ring mounting groove 3. A rubber ring 5 for seal is mounted in the rubber ring mounting groove 3, and a C-shaped ring 6 for preventing slip-off is inserted in the taperform annular groove 4 in a manner that size is capable of being reduced within the tapered annular groove 4. After coupling of a pipe, when an insertion port A is about to slip off, the C-shaped ring 6 is moved within the annular groove 5 in the direction of an open end togetherwith the insertion port A and wound around the outer surface of the insertion port A reduced in size by means of a component of force in a radial direction generated owing to contact with a tapered bottom. Simultaneously, an axial friction force with the tapered bottom 5A is increased to generate a slip-out resistance force.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a plastic pipe joint, and more particularly to an improvement of a plastic pipe joint having a slip-off prevention function.

[Conventional technology]

2. Description of the Related Art Conventionally, there has been known a plastic pipe joint for a plastic pipe that has a structure in which a socket is inserted into a socket and a rubber ring is inserted between the outer surface of the socket and the inner surface of the socket for sealing.

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

However, in the above-mentioned type of pipe joint, there is a risk that the insertion port may escape from the socket when an external force is applied in the direction in which the pipe comes out, and a measure to prevent this from coming off is required.

As a measure to prevent this from slipping out, a groove is provided in the opening direction that tapers from the rubber ring insertion part of the socket toward the opening end of the socket, and a C-shaped ring is inserted into this groove so that it can contact the outer surface of the socket. When a pull-out force is applied to the mouth, C
A pipe joint has been proposed in which a mold ring is wound around the outer periphery of the socket and the locking force thereof prevents the socket from coming off (Japanese Patent Application No. 147601/1999).

[Problems with conventional technology]

However, the above slip-out prevention structure requires forming a new groove on the inner surface of the opening end of the socket from the rubber ring mounting groove of the socket, the inner surface of which becomes shallower in the direction of the socket. In the case of so-called blow molding, in which a plasticized plastic pipe is press-fitted onto a mold to form a socket, the socket part is molded by expanding the diameter of the original pipe, so after molding the rubber ring mounting groove, the above-mentioned steps are performed. There was a drawback that it was difficult to accurately form a tapered groove like this.

In addition, even in the case of injection molding or mold molding, there is a drawback that it is troublesome to mold the grooves having a complicated cross-sectional shape.

[Problem to be solved by the invention]

In view of the above-mentioned problems, the present invention provides a plastic pipe joint in which a locking ring mounting groove to prevent the pipe from slipping out can be formed accurately even when performing injection molding, mold molding, or secondary molding by expanding the diameter of a plastic pipe. It was made with the purpose of providing.

[Technology that led to solving the problem]

That is, the plastic pipe joint according to the first aspect of the present invention is a plastic pipe joint comprising an enlarged diameter socket portion that receives a plastic pipe socket and has a rubber ring mounting groove formed on the inner surface near the open end. , an annular groove that tapers shallower toward the opening end from the inner wall on the open end side of the rubber ring mounting groove is integrally formed with the rubber ring mounting groove in an axial direction, and a sealing groove is formed in the rubber ring mounting groove. The present invention is characterized in that a rubber ring is attached to the tapered annular groove, and a C-shaped ring for preventing slippage is inserted into the tapered annular groove so that its diameter can be reduced. In the first aspect of the present invention, a spacer is inserted between the rubber ring installed in the rubber ring mounting groove and the slip-out prevention C-shaped ring inserted into the tapered shallow annular groove. It is something to do.

〔Example〕

Next, this invention will be explained in detail.

Fig. 1 is a sectional view of an embodiment of the present invention that is compatible with the first invention, Fig. 2 is a sectional view of the embodiment of Fig. 1 in use, and Fig. 3 is an embodiment of the invention that is based on the second invention. FIG. 4 is a cross-sectional view showing the embodiment of FIG. 3 in use.

The plastic pipe joint 1 of the present invention is formed with an enlarged diameter socket 1' that receives a plastic pipe socket A (Fig. 2) and has a rubber ring mounting groove 3 formed on the inner surface near the opening end 2. In the pipe fitting 1, an annular groove 4 that tapers shallower toward the opening end 2 from the inner wall 3A on the open end side of the rubber ring mounting groove 3 is continuous and integral with the rubber ring mounting a3 in the axial direction (arrow X). A sealing rubber ring 5 is attached to the rubber ring attachment 43, and a C-shaped ring 6 for preventing slipping out is inserted into the tapered annular groove 4 so as to be collapsible within the tapered annular a4. It is configured.

Furthermore, the plastic pipe fitting 1 according to the second invention has a rubber ring attachment a3 similar to the above pipe fitting 1 and an annular groove 4 that becomes shallow in a tapered shape, and has a rubber ring attached to the rubber ring attachment a3. A spacer 7 is inserted between the ring 5 and a C-shaped ring 6 for preventing slippage inserted into the annular groove 4 which becomes shallow in a tapered manner.

Note that the spacer 7 used has a cut surface 7A cut diagonally as shown in the figure or cut in steps so as to form a complete circumference.

In the case of secondary molding, the plastic pipe joint 1 described in Section 2 is molded in the steps shown in FIG. 5 and below.

That is, when the pipe end C of the plastic straight pipe B is heated to the visualization temperature and the heated end C is forcibly pushed into the diameter expanding mold to form the socket (Figs. 5 and 6). ), a convex mold 4' for forming a tapered shallow annular groove 4 is placed coaxially on the expanded diameter part E for forming the rubber ring of the diameter expanding mold, and a plasticized straight pipe C is placed on top of this convex mold 4'. Since the molding is carried out by riding on the plastic tube C, the change in diameter of the end portion of the plastic tube C which is expanded and deformed is reduced by the convex mold for forming the annular groove 4, and the molding can be performed precisely and quickly.

Thereafter, by reducing the diameter of the expanded die and pulling it out, the socket 1 is formed as shown in FIG.

[Effect]

When joining pipes using the plastic pipe fitting 1 of the present invention, as shown in FIG.
Insert the socket A with the

At this time, since the inner bottom surface 5A of the annular groove 5 is tapered so that the diameter increases toward the back, the C-shaped ring 6 moves to the large diameter portion and does not become an obstacle to the insertion of the insertion port A.

After the pipes are joined, when an external force is applied in the direction of the pipe axis and the socket A tries to come out, the C-shaped ring 6 moves along with the socket A in the annular groove 5 toward the open end, and comes into contact with the tapered inner bottom surface. The diameter is reduced by the generated radial component force and it wraps around the outer surface of the insertion port A, and at the same time increases the axial frictional force with the tapered inner bottom surface 5A and exerts a resistance force.

In the case of the second invention, the C-shaped retaining ring 6 and the rubber ring 5
Since the spacer 7 is interposed between the rubber ring 5 and the tapered annular groove 4, the rubber ring 5 is prevented from expanding toward the tapered annular groove 4 side.

〔effect〕

As explained above, in the pipe joint of the present invention, the tapered groove into which the ring that prevents the ring from slipping out is inserted is continuous with the rubber ring mounting groove, so that step deformation is alleviated. Regardless of whether the molding method is injection molding, mold molding, or secondary molding, the socket can be easily formed, and the stress that occurs when preventing it from slipping out can be alleviated, ensuring reliable prevention. It has the effect of

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the first embodiment of the present invention, and the second
The figure is a cross-sectional view showing the usage state of the embodiment of FIG. 1, FIG. 3 is a cross-sectional view of the second embodiment of the invention, and FIG.
5, 6, and 7 are cross-sectional views showing the state of use of the embodiment shown in the figure.

Claims (2)

[Claims] (1) In a plastic pipe fitting consisting of an enlarged diameter socket that receives a plastic pipe insertion port and has a rubber ring mounting groove formed on the inner surface near the opening end, the direction from the inner wall on the opening end side of the rubber ring mounting groove toward the opening end. An annular groove that becomes shallower in a tapered shape is formed continuously and integrally with the rubber ring mounting groove in the axial direction, and a sealing rubber ring is mounted on the rubber ring mounting groove, and
A plastic pipe joint characterized in that a C-shaped ring for preventing slippage is inserted into the tapered annular groove so that its diameter can be reduced. (2) A spacer is inserted between the rubber ring installed in the rubber ring mounting groove and the slip-out prevention C-shaped ring inserted into the tapered shallow annular groove. Plastic pipe fittings described in scope 1.