JPH10281358A - Forming method for protruded part of spigot of pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a protruded part without applying groove work to a spigot of a pipe cut in a laying work site and form the protruded part even in a thin- walled pipe without a problem. SOLUTION: A spigot ring 21 of peripheral direction single split interference convenience formed with a plurality of saw-toothed protrusive streaks 22 along an internal peripheral surface in an axial center direction is mounted in the periphery of a spigot 2 of a pipe 1. Next, the spigot ring 21 is given tightening force to the periphery of the spigot 2 from the outside, to make the protrusive streak 22 bite in a peripheral surface of the spigot 2. Thereafter, after the tightening force is released, a divided part in a peripheral direction of the spigot ring 21 is mutually connected by a connection piece.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a projection of a tube opening.

[0002]

2. Description of the Related Art Among cast iron tubes constituting a pipeline, in a seismic tube or the like, as shown in FIG. When the insertion port 2 is inserted into the receiving port of another pipe, the projection 3 engages with the lock ring on the receiving port side, thereby preventing the receiving port from coming out of the receiving port. Function is exhibited. A tapered surface 4 is formed on the outer periphery of the distal end of the insertion port 2 including the protrusion 3. The projection 3 has an end face 5 in the pipe diameter direction for engagement with the lock ring or the like.

[0003] By the way, when such a cast iron pipe is to be buried in the ground after the socket and the insertion port are joined to each other,
When the pipe lengths do not match, the length is adjusted by cutting the insertion side to a required length at the site where the pipe is laid. However, when a cut pipe is formed in a pipe such as an earthquake-resistant pipe having a projection 3 at the insertion opening 2, the projection 3
Therefore, it is necessary to newly form a protrusion.

For this reason, in the prior art, first, FIG.
As shown in (b), a cut pipe is formed at the end of the insertion port 2 having the projection 3 of the pipe 1, and thereafter, an annular groove 6 is formed on the outer periphery of the cut port 2 where the cut pipe has been formed as shown in FIG. Process. Insert 2
The outer peripheral taper surface 7 is machined at the tip of. And the same figure (c)
As shown in (1), a ring 8 which is tight in the circumferential direction is attached to the annular groove 6. The ring 8 has a tapered surface 9 leading to the outer peripheral tapered surface 7 formed at the tip of the insertion opening 2 and an end face 10 in the pipe radial direction facing the pipe body. Finally, as shown in FIGS. 4D and 5, the joining piece 12 is put on the split portion 11 of the ring 8, and the joining piece 12 and the end of the ring 8 are fixed to each other with rivets 13. For example, a projection having the same function as the projection 3 before the intubation can be formed.

[0005]

However, in such a conventional method, an annular groove 6 for mounting a ring 8 in a circumferential direction is formed on the outer periphery of the insertion port 2 after cutting the pipe on site. Therefore, there is a problem that the efficiency is low and the cost is increased. In addition, since the portion in which the annular groove 6 is machined has a smaller tube thickness than the original state, it is difficult to apply the tube to a tube with a thin tube originally, and it can be applied only to a tube with a thick tube. There are also problems.

Accordingly, the present invention has been made to solve the above-mentioned problems, and it has become possible to form a protruding portion without forming a groove in an insertion port for cutting a pipe at a laying site. It is an object of the present invention to be able to form a projection without a protrusion.

[0007]

SUMMARY OF THE INVENTION In order to achieve this object, an object of the present invention is to provide a plurality of sawtooth-shaped ridges formed along the inner peripheral surface in the axial direction, and to be inserted in a circumferentially divided manner. A mouth ring is attached to the outer periphery of the insertion opening of the pipe, and a fastening force is applied to the insertion ring from the outside to the outer periphery of the insertion opening to cause the ridge to bite into the outer peripheral surface of the insertion opening. Is released, and the circumferentially divided portions of the insertion ring are joined to each other by a joining piece.

[0008] In this case, the ridge bites into the outer peripheral surface of the insertion hole by an external tightening force, and the joining piece prevents the diameter of the insertion ring from being enlarged later. The projection is formed integrally with the outer periphery. Therefore, the protrusion can be easily and efficiently formed without performing the groove processing on the outer periphery of the insertion opening. Further, since the groove processing is not performed, the method can be applied to a thin pipe without any problem.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an insertion ring 21 as shown in FIGS. 1 to 3 is prepared at a place where a pipe is to be cut at a site where a pipeline is laid. This insertion ring 21 is J
The structural carbon steel of IS S55C of IS, which is formed harder than the cast iron pipe 1 by quenching, or the like, is formed to be tightly divided in the circumferential direction. On the inner periphery of the insertion ring 21, a ridge 22 of a saw tooth is formed. The protrusions 22 are formed in the circumferential direction, and are formed in a large number in the axial direction of the insertion ring 21. Each ridge 22 has a sawtooth cross-sectional shape as described above, and a steeply rising rising surface 23.
And a tapered surface 24 whose inclination is gentler than the rising surface 23. A tapered outer peripheral tapered surface 25 is formed on the outer periphery of an end of the insertion ring 21 on the rising surface 23 side, and a radial end surface 26 is formed on an end of the insertion ring 21 on the side of the tapered surface 24. In the circumferential division 27 of the insertion ring 21, both ends 28, 28 of the insertion ring 21 in the circumferential direction are formed thinner than the other portions by cutting off the outer peripheral side. Each end 28 is formed with a radial through hole 29 through which a rivet described later is passed.

Next, the diameter of the insertion ring 21 is expanded by elastic deformation, and as shown in the drawing, the outer circumference of the distal end of the insertion port 2 of the pipe 1 cut and cut at the installation site is fitted. Then, the insertion ring 21 that is easy to tighten is attached to the outer periphery of the insertion port 2 by its own elastic force.

Then, a fastening ring 31 is attached to the outer periphery of the insertion ring 21. This fastening ring 31
Are formed in the circumferential direction, and radially outward flanges 33, 33 are formed in the circumferentially divided portion 32, respectively. A bolt 34 is provided between the flanges 33, 33, and the bolts 34 and the nut 35 are used to tighten the flanges 33, 33 so that the flanges 33, 33 are close to each other. is there. That is, the fastening ring 3
1 is an inner peripheral surface 37 in contact with the outer peripheral surface 36 of the insertion ring 21.
And an inner tapered surface 38 in contact with the outer tapered surface 25 of the insertion ring 21. Furthermore, the clamping ring 31 has an inner peripheral flange 40 that contacts the end face 39 of the insertion opening 2 of the tube 1.

Therefore, after the inner peripheral flange 40 of the tightening ring 31 is brought into contact with the end face of the insertion opening 2 of the pipe 1,
By bringing the inner peripheral surface 37 and the inner peripheral tapered surface 38 of the tightening ring 31 into contact with the outer peripheral surface 36 and the outer peripheral tapered surface 25 of the insertion ring 21, the insertion ring 21 is axially positioned with respect to the insertion opening 2. Can be done.

Therefore, the fastening ring 31 is attached to the outer periphery of the insertion ring 21 as described above, and the bolt 34 and the nut 35 are operated in a state where the insertion ring 21 is positioned with respect to the insertion opening 2. 31 is reduced in diameter. Then, a fastening force to the outer circumference of the insertion port 2 is applied to the insertion ring 21 by the above, and the ridge 22 is
Is cut into the outer peripheral surface of.

Next, the bolt 34 and the nut 35 of the tightening ring 31 are operated in the opposite directions to
1 and the fastening ring 31 is removed from the insertion ring 21. Then, since the insertion ring 21 is formed so as to be tight, the state in which the ridge 22 bites into the outer peripheral surface of the insertion port 2 is maintained.

Therefore, a joint piece 42 similar to that shown in FIGS. 4D and 5 is provided in the divided portion 27, and a through hole formed in the joint piece 42 and an end of the insertion ring 21 are formed. 28, 28 formed through holes 29, 29
The joint piece 42 is fixed to the ends 28, 28 by rivets 43 by utilizing the above. Since it is necessary to fix the rivet 43 while the insertion ring 21 is mounted on the outer periphery of the insertion port 2, it is preferable to use a blind rivet or the like as the rivet 43.

Thus, the diameter of the insertion ring 21 is prevented from being increased, and the insertion ring 21 is integrated with the insertion port 2. Thereafter, the outer peripheral tapered surface 25 of the insertion ring 21
Then, if a tapered surface is formed on the outer periphery of the distal end of the insertion port 2, the same projection as before the cutting tube can be formed.

The projection formed in this manner contributes to the achievement of the anti-seismic function when the end face 26 of the insertion ring 21 is engaged with the lock ring on the receiving side. When the end surface 26 of the insertion ring 21 is engaged with the receiving port side and a pull-out force acts between the receiving port insertion ports, the force is such that the ridges 22 bite into the insertion port 2. As a result, the rising surface 23 of the ridge 22 acts on the insertion opening 2, so that it is reliably transmitted to the insertion opening 2. Therefore, even when the exit force acts between the receiving port and the receiving port, the integrated state of the receiving ring 21 and the receiving port 2 is reliably maintained, and the receiving ring 21 is separated from the receiving port 2. Accidents such as slipping out are prevented.

The ridge 22 of the insertion ring 21 is inserted into the insertion 2
The means for causing the insertion ring 21 to apply a tightening force to the outer periphery of the insertion port 2 so as to bite into the outer peripheral surface of the insertion ring 2 is not limited to the above-described tightening ring 31 and other means. It is also possible to use. For example, a wire rope may be wound around the outer circumference of the insertion ring 21, and a tightening force may be applied to the insertion ring 21 by tightening the wire rope.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An insertion ring is attached to the outer periphery of an insertion hole of a thin-walled tube having a nominal diameter of 250 mm and a minimum tube thickness of 6 mm, a tightening ring is set, and the divided portion is set to M20.
With a high tension bolt. When the tightening torque of the bolt at that time was 1000 kg · cm, a protrusion having a high detachment prevention force of 86 tons or more could be stably obtained.

[0020]

As described above, according to the present invention, a plurality of sawtooth-shaped ridges are formed along the inner peripheral surface in the axial direction, and the circumferentially-divided insertion ring which is tight in the circumferential direction is connected to the pipe. Attached to the outer periphery of the insertion hole, applying a tightening force from the outside to the outer periphery of the insertion hole to the insertion ring to make the ridge bite into the outer peripheral surface of the insertion hole, and then releasing the tightening force. Since the circumferential divided portions of the insertion ring are joined to each other by the joining piece, the insertion ring can be integrated with the outer periphery of the insertion hole, thereby forming a protrusion, and therefore, on the outer periphery of the insertion hole. Not only can the protruding portion be formed easily and efficiently without groove processing, but also since the groove processing is not performed, it can be applied to a thin-walled pipe without any problem.

[Brief description of the drawings]

FIG. 1 is a view for explaining a method of forming a projection of an insertion opening of a pipe according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a portion shown in FIG.

FIG. 3 is a cross-sectional view illustrating a step subsequent to FIGS. 1 and 2;

FIG. 4 is a view for explaining a conventional method of forming a projection of an insertion opening of a pipe.

FIG. 5 is a cross-sectional view of a main part of a projection of a conventional pipe insertion opening.

FIG. 6 is a view showing a projection of an insertion opening of a conventional pipe before a cut pipe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pipe 2 Insert 21 Insert ring 22 Ridge 31 Tightening ring 42 Joining piece

Claims (1)

[Claims] 1. A ring having a plurality of sawtooth-shaped ridges formed along an inner peripheral surface in an axial direction along a circumferentially-divided tight-fitting insertion ring is attached to an outer periphery of an insertion hole of a pipe. Applying a fastening force to the outer periphery of the insertion ring from the outside to the insertion ring to cause the ridge to bite into the outer peripheral surface of the insertion hole, and then releasing the tightening force, then dividing the insertion ring in the circumferential direction. A method for forming a projection at an insertion opening of a pipe, wherein the projections are joined to each other by a joining piece.