JP2000130658A - Pipe with lug at spigot and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently form spigot lugs when a cut pipe is applied to a pipe and to give sufficient strength to a portion forming the lugs. SOLUTION: Multiple lug pieces 24 are arranged along the peripheral direction on the outer periphery of the spigot 26 of a pipe 25, and the lug pieces 24 each are welded to the outer periphery of the spigot 26. In detail, multiple piece main bodies 28 formed with through holes 30 in the radial direction are arranged along the peripheral direction on the outer periphery of the spigot 26 of the pipe 25, a mandrel 34 coupled with the piece main bodies 28 from the outside in the radial direction is inserted into the through holes 30 of the piece main bodies 28, and the mandrel 34 is stud-welded to the outer periphery of the spigot 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tube having a projection at an insertion port and a method for manufacturing the same.

[0002]

2. Description of the Related Art As one type of pipe joint, there is a slip-on type pipe joint. This slip-on type pipe fitting is configured such that a receiving material and a receiving material can be joined by inserting a sealing material into the receiving material while compressing the sealing material into the receiving material. ing. As a slip-on type pipe joint provided with a detachment prevention function, a detachment prevention pipe joint having a configuration shown in FIG. 4 has been proposed.

That is, in FIG. 4, a receiving port 2 is formed at an end of one of the cast iron pipes 1 joined to each other.
An annular rubber sealing material 4 is disposed in the sealing material receiving groove 3 on the inner periphery of the receiving port 2, and a lock ring receiving groove 5 is formed on the back side of the sealing material receiving groove 3. 5 is provided with a lock ring 6 divided in a circumferential direction. Outer peripheral side of lock ring 6 and lock ring receiving groove 5
A holding rubber ring 7 for holding the lock ring 6 in a centered state is disposed between the holding ring 7 and the inner peripheral side.

On the outer periphery of the distal end of the insertion port 9 of the other cast iron tube 8, a projection 10 that can engage with the lock ring 6 from the back side of the reception port is formed. The protruding portion 10 is formed by, for example, welding a ring-shaped member to the outer periphery of the insertion opening 9 and integrating the entire periphery. Insert 9 including this projection 10
A tapered surface 11 serving as a guide when inserting the insertion opening 9 into the receiving opening 2 in which the sealing material 4 and the lock ring 6 are accommodated is formed on the outer periphery of the distal end of.

[0005] In the case where cast iron pipes are joined to each other and buried in the soil at the site where the pipe is laid, if the pipe lengths do not match, it is necessary to adjust the pipe length by cutting pipes. However, as shown in FIG.
When the cut pipe is cut for the cast iron pipe 8 having 0, it is necessary to newly form a projection at the insertion opening.

For this reason, conventionally, for example, as shown in FIG. 5 (a), when a cut pipe is cut at an appropriate position 13 on a cast iron pipe 8 having a projection 10 at the end of an insertion port 9 (b), An annular groove 14 and a new tapered surface 15 are machined on the outer periphery of the distal end portion of the pipe 8 cut as shown in FIG. Insert the insertion ring 16. The insertion ring 16 protrudes outward in the circumferential direction from the outer peripheral surface of the tube 8 and has a tapered surface 17 that is continuous with the tapered surface 15. And FIG.
As shown in the figure, in the circumferential division, the ends 18, 18 of the ring along the circumferential direction are formed to be thin, and the connection piece 19 is arranged between the thin ends 18, 18. One end and the other end of 19 are fixed to ends 18, 18 of the insertion ring 16 by rivets 20, respectively.

[0007]

However, in the method of forming a new protrusion at the tip of the cast iron tube 8 in this manner, an annular groove 14 must be newly formed on the outer periphery of the tube 8. There is a problem that efficiency is poor. In addition, the annular groove 14
In the part where is processed, the pipe thickness becomes thin, and only the insertion ring 16 is fitted in that part and the ends 18, 18 are fixed, and no special means for improving the strength is taken. Cut pipe processing in the so-called 1
The fact is that it is performed only at the seed tube.

Therefore, the present invention solves such a problem and efficiently forms an insertion projection at the time of a cutting tube, and also makes the portion having the projection have sufficient strength. The purpose is to:

[0009]

According to the present invention, a plurality of projection pieces are arranged along a circumferential direction of an outer circumference of an insertion opening of a pipe, and each of the projection pieces is connected to an outer circumference of the insertion opening. It is made to be welded.

Further, according to the present invention, a plurality of piece bodies are arranged along a circumferential direction of an outer periphery of a tube insertion port, and a through hole is formed in each piece body in a tube radial direction. A metal core that engages with the piece main body is mounted from the outside, and this metal core is welded to the outer periphery of the insertion opening.

The present invention further provides a plurality of piece bodies each having a through-hole in the pipe diameter direction formed along the circumferential direction of the outer periphery of the insertion opening of the pipe, and a pipe is formed in the through-hole of each piece body. A core metal to be engaged is fitted from the outside in the radial direction, and this core metal is stud-welded to the outer periphery of the insertion opening.

Therefore, according to the present invention, an insertion projection can be efficiently formed at a piping work site only by welding without forming an annular groove on the outer periphery of the insertion opening of the pipe. In addition, since the annular groove is not machined, the tube thickness is not reduced, so that a sufficient strength is given to the portion where the insertion projection is formed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIGS. 1 and 2, reference numeral 25 designates a ductile cast iron pipe having a cut pipe formed at the tip of an insertion opening 26 and a new tapered surface 27 formed on the outer periphery of the cut portion.
Has been processed. A projecting piece 24 is used to form a new projecting portion on the outer periphery of the insertion opening of the cast iron tube 25 provided with the cut tube. This projection piece 24 is shown in FIGS.
As shown in FIG. 2, the piece body 28 and the metal core 34 are provided.

The piece main body 28 is formed of ductile cast iron such as FCD400, and a plurality of pieces are arranged along the outer circumference of the tube 25. Each piece body 28 has an inclined surface 29 that is continuous with the tapered surface 27 of the tube 25. Each piece body 28 has a through hole 3 in the pipe diameter direction.
0 is formed. The through hole 30 has a large diameter portion 31 at an outer position along the pipe diameter direction, a small diameter portion 32 at an inner position along the pipe diameter direction, and a large diameter portion 31.
And a step portion 33 at the boundary between the small-diameter portion 32 and the small-diameter portion 32.

A metal core 34 is fitted in the through hole 30 in the piece body 28. This cored bar 34
It is formed of an Fe-Ni alloy or the like,
Large-diameter portion 35, small-diameter portion 36, and step 3 corresponding to through-hole 30
The step 37 is configured to be able to engage with the piece body 28 from the outside in the tube radial direction by contacting the step 37 with the step 33 of the through hole 30.

When the core metal 34 is fitted into the through hole 30, the outer end face 3 located at an outer portion along the pipe radial direction is formed.
8 is formed so as to be flush with the outer surface 39 of the piece body 28. Further, a recess 40 into which a welding gun for stud welding, which will be described later, fits is formed in the outer end surface 38.
Are formed. An inner end face 41 located at an inner portion of the cored bar 34 along the pipe radial direction is formed in a tapered shape whose center portion slightly projects. A projection 42 is formed at the center of the tapered inner end surface 41.

In such a configuration, as shown in FIG. 1A, the piece main body 28 is temporarily fixed at a predetermined position on the outer peripheral surface of the tube 25 by, for example, a double-sided adhesive tape or the like, and the core metal 34 is inserted into the through hole 30. And engaged with the piece body 28 from the outside in the pipe radial direction. Then, using a gun 45 for stud welding, the tip of the gun 45 is fitted into the concave portion 40 of the metal core 34 as shown in FIG.

Then, since the projections 42 of the metal core 34 formed of an Fe-Ni alloy having good weldability are in contact with the cast iron tube 25, an electric current flows and an arc is generated. Then, the inner end surface 41 is melted so as to spread over the entire tapered inner end surface 41, and the core metal 34 is welded to the surface of the cast iron pipe 25 as shown in FIG. 4
6 is the welded portion. Then, since the core metal 34 and the piece main body 28 are engaged with each other by the steps 33 and 37,
At the same time, the piece body 28 is fixed to the outer surface of the cast iron tube 25.

Then, as shown in FIG. 2, a plurality of projection pieces 24 are sequentially fixed along the outer periphery of the pipe 25 by welding in the same manner, so that the projection 47 Can be formed.

In the above description, each piece body 28
Although the example in which a single through hole 30 is formed and a metal core 34 is fitted is illustrated, a configuration in which a plurality of through holes 30 are formed in one piece body 28 and the metal core 34 is fitted may be used. Then, each piece body 28 can be formed longer in the circumferential direction, and the number of piece bodies 28 arranged over the outer periphery of the tube 25 can be reduced. Projection piece 24
Can be fixed to the outer periphery of the pipe 25 by arranging them so that they are continuous with each other as shown in FIG.
It is also possible to fix the projection pieces 24 to the pipe 25 in a state where they are arranged at intervals in the circumferential direction.

In the above description, the case where the piece main body 28 in which the inclined surface 29 is formed in advance is used has been described, but after the projection piece 24 is welded to the outer periphery of the pipe 25, the pipe 25 and the projection piece 24 are welded. Alternatively, the tapered surface 27 may be integrally formed.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a so-called three kinds of small pipes made of ductile cast iron having a diameter of 100 mm, 25 pieces of projections having the structure shown in FIG. Formed. Then, a pipe joint having the same configuration as that of FIG. 4 was formed using the pipe having the protrusion formed in this manner, and the detachment preventing force was confirmed. Then, 35
A detachment preventing force having a high tf could be stably obtained.

[0023]

As described above, according to the present invention, a plurality of projecting pieces are arranged along the circumferential direction of the outer periphery of the insertion opening of the pipe,
Since each protruding piece is welded to the outer circumference of the insertion port, the insertion protruding part can be efficiently installed at the plumbing construction site only by welding work without forming an annular groove on the outer circumference of the pipe insertion port. It can be formed well. In addition, since the annular groove is not machined, the tube thickness is not reduced, so that sufficient strength can be imparted to the portion where the insertion projection is formed. Even in this case, it is possible to cut the pipe at the piping site and join it with the separation preventing joint.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a tube having a projection at an insertion opening and a method of manufacturing the same according to an embodiment of the present invention.

FIG. 2 is a side view of the portion shown in FIG.

FIG. 3 is an enlarged view of a protrusion piece in FIGS. 1 and 2;

FIG. 4 is a cross-sectional view of a conventional separation preventing pipe joint to which the present invention can be applied.

FIG. 5 is a view illustrating a conventional pipe having a projection at an insertion port and a method of manufacturing the pipe.

FIG. 6 is a diagram illustrating a conventional pipe having a projection at an insertion port and a method of manufacturing the pipe.

[Explanation of symbols]

 24 Projection piece 25 Cast iron tube 26 Insertion opening 28 Piece body 30 Through hole 34 Metal core 46 Welded part

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3H015 FA04 3H104 JA08 JB02 JC10 JD06 KA04 KB04 KB07 KB11 LF05 LG02 LG22 3H111 AA01 BA02 CB14 CB28 DA26 DB17 EA16

Claims (3)

[Claims] 1. A plurality of projecting pieces are arranged along a circumferential direction of an outer periphery of an insertion opening of a pipe, and each of the projecting pieces is welded to an outer periphery of the insertion opening. Tube with a section. 2. A plurality of piece bodies are arranged along a circumferential direction of an outer periphery of an insertion opening of a pipe, and a through hole in a pipe radial direction is formed in each piece body. A pipe having a projection in an insertion hole, wherein a core metal related to the piece main body is mounted, and the core metal is welded to an outer periphery of the insertion hole. 3. A plurality of piece bodies each having a through-hole in the pipe diameter direction are arranged along the circumferential direction of the outer periphery of the insertion opening of the pipe, and the through-holes of each piece body are provided in the through-holes of this piece body. A method of manufacturing a pipe having a projection at an insertion hole, wherein a core metal engaged from the outside is fitted, and the core metal is stud-welded to an outer periphery of the insertion hole.