JPH0439489A - Pipe joint - Google Patents

Abstract

PURPOSE:To increase the strength of a pipe joint and prevent it from the diameter expanding deformation or breakage by constituting a socket opening end part formed with a groove and double folded-back part. CONSTITUTION:A socket 2 is formed circumferentially on the inner surface 4 from the rubber ring 3A interposing part 3 to the opening end side of a socket 2 with a groove 5 having a section tapered toward the socket opening end side to make the groove shallow, and a split ring 7 contacting the outer surface of an insert pipe 6 and having the diameter received in the taper expanded diameter part of the groove 5 is received in the groove. In a pipe joint for preventing the drawing-out by the split ring 7, the socket opening end 2A formed with the groove 5 is constructed to have a double folded-back part. This double folded-back structural part may be constructed to nip a core material 8 having higher rigidity than a plastic socket material if necessary. Thus, accidents such as diameter expanding deformation, breakage, etc., can be effectively prevented even if any strong force is applied to the socket opening end so that the socket capable of resisting severe conditions is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pipe joint, and more particularly to an improvement in a pipe joint that prevents extraction.

[Conventional technology]

BACKGROUND ART Conventionally, a pipe joint is known in which a rubber ring is inserted between an inner surface of a socket and an outer surface of a socket for connection.

This type of pipe fitting has the advantage of being able to absorb expansion and contraction, bending, eccentricity, etc. of the pipe due to external forces acting on the pipe and temperature changes, but it is relatively easy for the pipe to escape if an external force is applied to the pipe connection in the direction of disconnection. It has its drawbacks.

Therefore, various measures are taken to prevent this type of pipe joint from being pulled out without impairing the above-mentioned advantages.

As shown in Fig. 3, this pull-out prevention means includes a groove in which the cross-section becomes shallower in a tapered shape toward the opening end of the socket on the inner surface C on the opening end side from the rubber ring insertion part B in the socket. form in the direction,
A split ring F that is in contact with the outer surface of the insertion hole E and has a diameter that can be accommodated in the tapered enlarged diameter part of the groove is stored in this groove, and the split ring F
The applicant of the present application has proposed a pipe joint that prevents the pipe from being pulled out by utilizing the force of diameter reduction deformation along the tapered groove of the pipe.

[Problems with conventional technology]

However, when the above-mentioned combination of the taper groove and the split ring F is used to prevent pull-out, when the split ring F moves toward the shallow bottom of the groove due to the movement of the insertion port E, a very strong radial force is generated. This acts to push and expand the opening end of the socket.

In this case, metal sockets do not have this problem, and plastic injection molded sockets do not have such problems because the wall thickness at the opening end of the socket can be thickened and the shape can withstand the diameter expansion force. When one end of a plastic pipe is secondary-molded to form a socket, the above process is difficult; simply molding the socket may result in insufficient strength of the socket and the split ring may fall out due to diameter expansion deformation. Also, I found out that the opening end of the socket may tear.

[Problem to be solved by the invention]

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a pipe joint that can reliably prevent the deformation or damage of the socket when preventing the pipe from being pulled out.

[Technology that led to solving the problem] That is, the pipe joint of the present invention has a groove in the circumferential direction on the inner surface of the opening end side from the rubber ring insertion part of the socket, the cross section of which becomes shallower in a tapered shape toward the opening end side of the socket. In a pipe joint formed in the groove, a split ring that is in contact with the outer surface of the insertion port and has a diameter that can be accommodated in the tapered enlarged diameter part of the groove, and is prevented from being pulled out by the split ring,
The socket opening end portion in which the groove is formed has a double folded structure, and furthermore, the socket opening end portion is sandwiched between a core made of a material having higher rigidity than the socket material. It is characterized by a double folded structure.

〔Example〕

Next, the present invention will be explained in detail.

FIG. 1 is a sectional view of an embodiment of the present invention, and FIGS. 2A to 2C are explanatory diagrams showing the manufacturing process of the embodiment.

The pipe joint 1 of the present invention has an insertion portion 3 of the rubber ring 3A of the socket 2.
A groove 5 whose cross section tapers shallower toward the opening end of the socket is formed in the circumferential direction on the inner surface 4 on the opening end side, and is in contact with the outer surface of the insertion rod 6 and has a tapered diameter enlargement. In a pipe joint that stores a split ring 7 with a diameter that can be stored in the pipe joint and prevents it from being pulled out by the split ring 7, the socket opening end portion 2A in which the groove 5 is formed has a double folded structure. There is.

Further, if necessary, this double folded structure portion is constructed such that a core material 8 having higher rigidity than the plasti-socket material is sandwiched therebetween.

In the above, the core material 8 may be a thin metal plate, a cord-shaped metal core, or a core made of plastic fiber wound spirally to form FRP.

The folded portion 2A is manufactured by the steps shown in FIGS. 2A to 2C.

That is, in the step of molding the socket 2 with the mold 10 for molding the socket 2, after the metal core 8 is arranged in a wound state around the outer periphery of the opening end, the folding mold 11 is arranged. , this mold 11 is brought closer to the opening end of the socket and forcibly pushed forward.
(Figure 2 mouth).

As a result of this pushing, the opening end is folded back outward,
It has a double structure with a core material 8 sandwiched therebetween.

Thereafter, as shown in FIG. 2C, the outer periphery is uniformly compressed and shaped using a pressing die 13, and the groove 5 is formed.

[Effect]

In the pipe joint 1 of the present invention, when connecting pipes, the rubber ring 4 and the split ring 7 are stored in their respective storage grooves in the socket 2, and the socket B is inserted.

At this time, as shown in FIG. 1, the opening end of the socket 2 has a double structure or a double structure with the core material 8 sandwiched between the sockets 2 and 3, so that the strength is strong and the split ring 7 moves within the tapered groove. Therefore, even if a strong radial force is applied, the diameter will not be deformed or damaged.

〔effect〕

As explained above, according to the pipe joint of the present invention, even if a strong force is applied to the opening end of the socket when the socket tries to escape from the socket, the self-deformation such as diameter expansion deformation and breakage can be effectively prevented. It is possible to prevent this from happening and create a socket that can withstand even harsher conditions.

Further, in manufacturing, it is only necessary to add a folding mold to one end of a conventional socket molding mold, so that manufacturing can be easily performed.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, FIGS. 2A to 2C are sectional views showing manufacturing steps of the embodiment of the invention, and FIG. 3 is a sectional view of a conventional example. Circle 3

Claims (2)

[Claims] (1) A groove is formed in the circumferential direction on the inner surface of the opening end side of the rubber ring insertion part of the socket, the cross section of which becomes shallower in a tapered shape toward the opening end side of the socket, and in the groove, the groove is in contact with the outer surface of the socket and In a pipe joint in which a split ring with a diameter that can be stored in the tapered expanded diameter part of the groove is prevented from being pulled out by the split ring, the socket opening end portion where the groove is formed has a double folded structure. A pipe joint that is characterized by the following characteristics: (2) The pipe joint according to claim 1, wherein the socket opening end portion has a double folded structure with a core made of a material having higher rigidity than the socket material sandwiched therebetween.