JP2004347088A - Method of forming projection of insertion opening and insertion opening ring retaining device used for the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the amount of cutting of an insertion opening ring 4 in a pipe joint having an expanding/contracting function in which an insertion opening of one pipe is inserted in a receptacle opening of the other pipe. <P>SOLUTION: In the structure of the pipe joint in which the receptacle opening 1a of one pipe 1 receives the insertion opening 2a of the other pipe 2 therein in such a state that a projection 4 of the insertion opening 2a is inserted beyond a lock ring 3, the projection of the insertion opening 2a is formed. The insertion opening ring 4 is press-fitted on and secured to the end portion of the insertion opening 2a so that the rear end face of the insertion opening ring 4 is positioned at a boundary t between both tapered surfaces 2b, 4b. Thereafter, the insertion opening ring 4 and the end portion of the insertion opening are cut to form the tapered surfaces 2b, 4b. Since it is unnecessary to cut the whole of the insertion opening ring, the cutting range is minimized so that the workability is preferable. When cutting to form the tapered surfaces, it is preferable to perform R-cut of a distal end outer peripheral edge of the insertion opening. Because only the pipe main body is cut when performing the R-cut, even a thin cutting edge is enough in strength for the cutting work, and such a cutting implement 30 as shown in Fig. (a) can be used. A plurality of pawls which moves in the radial direction from the axial center of a cast-iron pipe are provided and the ring 4 is received by stepped portions of the respective pawls so that the ring 4 coincides with the boundary. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for forming a projection on the outer peripheral surface of the insertion port, which constitutes a pipe joint with a telescopic function in which an insertion port of the other pipe is inserted into a receiving port of one pipe, and an insertion ring holding device used at that time. It is about.
[0002]
[Prior art]
In order to form fluid pipes such as water pipes and gas pipes in the ground, it is common to connect ductile cast iron pipes and to connect the duct pipes to one end of the cast iron pipe. A pipe joint structure in which an insertion port is formed at the other end, and the insertion port is inserted into the receiving port. In recent years, in the case of the pipe joint structure, even when an unsteady external force directly hits the pipeline due to an earthquake or the like, seismic resistance for absorbing and relaxing the external force at the pipe joint has been strongly required. The one with the expansion and contraction function came to be adopted.
[0003]
As an example of the pipe joint having the expansion and contraction function, there is an NS type joint shown in FIG. 9. This joint forms a groove 3 a around the entire inner surface of a receiving port 1 a of one pipe 1, and a lock ring 3 is formed in the groove 3 a. And the outer surface of the end of the insertion port 2a of the other pipe 2 is formed as a tapered surface 2b having a downward slope toward the front end, and the insertion ring is fixed to the outer periphery of the insertion port 2a at the rear end of the tapered surface 2b. A protrusion 4 is formed, and an outer peripheral surface of the protrusion 4 is a taper surface having the same inclination that is continuous with the taper surface 2b, and the other tube 2 is inserted into the receiving port 1a of the one tube 1. The mouth 2a is configured so that the protrusion 4 is inserted over the lock ring 3 (in the state of the center chain line of the insertion opening 2a). In the drawing, 5 is a lining layer, and 6 is a packing (rubber ring).
[0004]
When an unsteady external force directly hits a pipe line due to an earthquake or the like, this NS type joint is resistant to the insertion force until the tip of the insertion port 2a comes into contact with the inner surface step 1b of the receiving port 1a as shown by a chain line. It moves until the protrusion 4 of the insertion port 2a comes into contact with the lock ring 3 as shown by a chain line with respect to the pull-out force, thereby absorbing and relaxing the external force and preventing the insertion port 2a from being pulled out.
[0005]
In this type of pipe joint having a projection 4 at the insertion port 2a, the projection 4 can be formed integrally with the pipes 1 and 2 (the insertion port 2a) at the same time, and by press-fitting the insertion ring. There is one in which the insertion port ring 4 is fixed to the insertion port 2a by welding or the like.
[0006]
As shown in FIGS. 5 (a) and 5 (b), the projection ring is formed by using the insertion ring 4 until the rear end face 4c of the insertion ring 4 is flush with the end face of the insertion port 2a. Then, as shown in FIGS. 6B and 8B, the outer peripheral surfaces of the ends of the insertion ring 4 and the insertion port 2a are tapered by the cutting blade 30 having the inclined blade surface. Cutting. At this time, as shown in FIG. 7, there may be a case where the outer peripheral edge of the insertion port end is round-cut c. In the figure, a chain line portion is a cutting portion (see Patent Documents 1 and 2).
[0007]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 9-178059 [Patent Document 2]
JP-A-10-153285
[Problems to be solved by the invention]
The insertion ring (projection) 4 is defined by a standard to use a material having high-strength mechanical properties for the pipes 1 and 2, for example, an FCD420 or more for the pipes 1 and 2 4 uses FCD600-3 or more.
[0009]
For this reason, as can be understood from FIG. 6B, the conventional method of forming the projection 4 of the insertion port 2a cuts almost half of the hard insertion ring 4, so that the workability is poor. In addition, the life of the cutting tool is short.
[0010]
In addition, in the case where a round cut c is made on the outer peripheral edge of the insertion port end, conventionally, as shown in FIG. 8B, after the tapered surface 2b is formed, the round cut operation is performed, and the processing is performed. It is performed by a grinder, and the workability is poor.
[0011]
An object of the present invention is to reduce a cutting area of an insertion ring.
[0012]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, as can be understood from FIG. 6 (b), the present invention is directed to the insertion of the end side (tip side left side in FIG. 6) from the boundary line between both tapered surfaces of the insertion end and the insertion ring. Paying attention to the fact that the entire mouth ring portion (the inner and outer surfaces) is cut and does not need to be present, the insertion ring is press-fitted and fixed to the boundary between the tapered surfaces. The end of the insertion opening was cut to form the tapered surface.
[0013]
This eliminates the need to cut the entire insertion ring and requires only a minimum amount of cutting work, thereby improving workability. Also, the insertion ring can be narrower in width than the conventional one, so that the processing cost is reduced, and the cost is accordingly reduced.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
As an embodiment of the present invention, a groove is formed on the entire inner surface of the receiving port of one tube, a lock ring is fitted into the groove, and the outer surface of the insertion port end of the other tube is tapered with a downward slope toward the tip. Surface, and a projection is formed by fixing the insertion ring to the outer periphery of the insertion port at the rear end of the tapered surface, and the outer peripheral surface of the projection is a tapered surface of the same inclination continuing to the tapered surface. And a method of forming a projection of the insertion port in a pipe joint structure in which the insertion port of the other pipe is inserted into the socket of the one pipe by passing the projection over the lock ring. Then, the insertion ring is press-fitted and fixed to the end of the insertion port at the end of the insertion port until the rear end surface is located at the boundary between the tapered surfaces, and thereafter, the insertion ring and the insertion port end are cut to form the tapered surface. A configuration may be employed.
[0015]
When cutting the tapered surface, it is preferable to make a round cut on the outer peripheral edge of the insertion port end. Since the round cut is performed only for the pipe main body, a thin blade is sufficient in terms of strength. For example, as shown in FIG. With the tool, the outer peripheral edge of the front end of the insertion end can be cut simultaneously with the cutting of the tapered surface of the insertion end and the insertion ring.
[0016]
In these molding methods, when press-fitting the insertion ring into the insertion port, a device for holding the insertion ring may be appropriately adopted, for example, insertion of a face plate against which the insertion port end is pressed. A plurality of claws are provided at equal intervals around the axis of the mouth, the claws moving radially from the axis, and each of the claws is urged toward the axis by an elastic body. A stepped portion that rises toward the center is formed, and the rising surface of the stepped portion of each claw is in the same plane around the axis, and the same surface is formed by the two tapered surfaces from the insertion end end pressing surface of the face plate. The insertion ring is fitted into each of the claws so that the rear end surface thereof comes into contact with the rising surface of the step portion, and each of the claws is inserted by the urging force of the elastic body. Holds the insertion ring by pressing against the outer peripheral surface of the ring To adopt a configuration that.
[0017]
In this holding device, the rising surface of the step portion of each claw coincides with the position of the boundary line between both tapered surfaces from the insertion end pressing surface of the face plate, and the insertion ring is inserted into each claw and the rear end surface is set to the step portion. Pressing the end of the insertion hole into the insertion ring and pressing it against the pressing surface of the face plate to support it by contacting with the rising surface of the The insertion ring is centered, and the insertion ring is press-fitted and fixed to the insertion end with its rear end face located at the boundary between the two tapered surfaces. For this reason, the above-mentioned insertion port projection can be formed smoothly and accurately.
[0018]
【Example】
One embodiment of the present invention is shown in FIGS. 1 to 4, and also in this embodiment, as shown in FIG. 1, a fixed plate 11 is provided at the tip of a piston rod 10 of a hydraulic cylinder as in the prior art. The face plate 12 is bolted to 11 so that the face plate 12 can advance and retreat on the same line with respect to the receiving face plate 13 by a hydraulic cylinder. The fixation of the face plate 12 and the fixed plate 11 is optional, as shown by a chain line in FIG. The holding device 20 for the insertion ring 4 is provided on the face plate 12. The cast iron pipe 1 is held horizontally by appropriate means by contacting the receiving port 1a with the face plate 13 and, in the supported state, the insertion port 2a is advanced with respect to the face plate 12 (holding device 20). As the insertion port 2a is inserted into the holding device 20, the insertion port 2a is fitted to the insertion ring 4 previously fitted to the holding device 20, and the insertion ring 4 is pressed into the insertion port 2a.
[0019]
The holding device 20 of the insertion ring 4 includes a four-part holding plate 21 and a claw 22. The holding plate 21 is bolted to the face plate 12, and a housing 23 of the claw 22 is provided between the holding plates 21. It is fitted. The housing 23 can be moved in the radial direction from the axis r of the cast iron pipe by a rail / groove structure, and is fixed by screwing and fastening a bolt (not shown) from the back surface of the face plate 12. The bolts are screwed into the housing 23 through the slots (not shown) in the radial direction formed in the face plate 12, and the housing 23 can be mounted on the surface by appropriately selecting the positions of the bolts in the slots. The panel 12 (holding plate 21) is fixed at a required position in the radial direction. At this time, the head of the bolt may be buried in the face plate 12 or protruded. The claw 22 can be moved in the radial direction by a rail / groove structure like the housing 23, and the plunger 24 is inserted into the sleeve 28 of the housing 23 so as to be able to protrude and retract, and is pressed by a spring 25. The pawl 22 is urged toward the center by the spring 25. The urging force is adjusted by the degree of screwing of the bolt 26.
[0020]
The inner surface 22a of the claw 22 is tapered downward from the outer end toward the axis r, and a step 27 is formed at the end. The step 27 is guided by the tapered surface 22a, and the insertion ring 4 The step 27 is fitted into the claw 22 and is supported. The insertion ring 4 has a width two-thirds that of the conventional one (see FIG. 8). The distance a (position: see FIG. 1) of the step portion 27 from the surface of the face plate 12 is from the end face of the insertion opening 2a to the outer peripheral surface and the boundary line t between the tapered surfaces 2b and 4b of the projection 4. As shown in FIGS. 4 (a) and 4 (b), when the insertion opening 2a is press-fitted into the insertion opening ring 4 of the holding device 20, the spring 25 of each of the claws 22 passes through the spring 25. The insertion ring 4 is centered in accordance with the press-fitting of the insertion port 2a by the advance and retreat, and the insertion ring 4 is press-fitted to the position (distance a) of the boundary line t of the insertion port 2a.
[0021]
When the insertion ring 4 is press-fitted into the insertion port 2a, the piston rod 10 of the hydraulic cylinder is retracted, the holding device 20 is retreated from the insertion port 2a, and the cast iron pipe is moved to that state or another position. The groove 4a of the insertion ring 4 is welded by overlay welding to fix the ring 4 to the insertion hole 2a, and then, as shown in FIG. The end of the insertion opening 2a and the end of the ring 4 are formed on the tapered surfaces 2b and 4b, and a round cut c is performed. At this time, since the round cut c is a part for cutting the cast iron pipes 1 and 2 (insertion port 2a), the tip part 31 can be cut smoothly and the part thereof is not damaged. The build-up weld is made flush with the other outer peripheral surface by cutting.
[0022]
Although the embodiment is the case of the NS type joint, the present invention can be applied to any joint as long as the joint structure has a projection formed by fitting the insertion ring 4 into the insertion opening 2a. Of course. In addition, other than the spring 25, a material having a similar function, for example, an air cylinder (damper) may be used as the elastic body.
[0023]
【The invention's effect】
According to the present invention, as described above, the cutting amount of the insertion ring is reduced, so that the workability is improved.
[Brief description of the drawings]
1 is a schematic view of an embodiment; FIG. 2 is a perspective view of a main part of the embodiment; FIG. 3 is a front view of the holding device; FIG. 4 is a press-fit operation diagram of an insertion ring of the embodiment; FIG. 6 is a press-fitting action diagram of a conventional insertion port ring. FIG. 6 is a taper surface forming action diagram at the insertion port. FIG. 7 is an enlarged sectional view of a main part of the insertion port. FIG. Cross section of main part of NS type joint [Explanation of symbols]
1, 2 Cast iron tube 1a Reception port 2a Insertion port 2b Insertion end outer peripheral tapered surface 3 Lock ring 4 Insertion ring (projection)
4b Insertion ring taper surface 10 Hydraulic cylinder rod 11 Fixing plate 12 Face plate 13 Receiving surface plate 20 Insertion ring holding device 21 Holding plate 22 Claw 25 Spring 30 Cutting blade 31 Cutting edge R cut part c Round cut r Cast iron pipe Axis t boundary

Claims (3)

A groove 3a is formed all around the inner surface of the receiving port 1a of one of the tubes 1, a lock ring 3 is fitted into the groove 3a, and the outer surface of the other end of the insertion port 2a of the other tube 2 has a tapered surface with a downward slope toward the tip. 2b, a projection is formed by fixing the insertion ring 4 to the outer periphery of the insertion opening 2a at the rear end of the tapered surface 2b, and the outer peripheral surface of the projection 4 has the same slope continuing to the tapered surface 2b. The pipe joint structure in which the insertion port 2a of the other pipe 2 is inserted into the receiving port 1a of the one pipe 1 by inserting the protrusion 4 over the lock ring 3 It is a method of forming the protrusion 4 of the insertion port 2a,
The insertion ring 4 is press-fitted and fixed to the end of the insertion opening 2a until the rear end surface thereof is positioned at the boundary line t between the tapered surfaces 2b and 4b. Thereafter, the insertion ring 4 and the insertion end are cut. And forming the tapered surfaces 2b and 4b by using the method. 2. The method according to claim 1, wherein a round edge c is formed on the outer peripheral edge of the front end of the insertion port at the same time as the tapered surface of the insertion port end and the insertion port ring 4 are cut. The apparatus for holding the insertion ring 4 when the insertion ring 4 is press-fitted into the insertion port 2 a in the method of forming the insertion port protrusion 4 according to claim 1 or 2,
A plurality of claws 22 are provided at positions at equal intervals around the axis r of the insertion port 2a of the face plate 12 on which the end of the insertion port 2a is pressed. Urges toward the axis r, and a step 27 is formed on the inner surface of each of the claws 22 and rises toward the axis r. The rising surface of the step 27 of each of the claws 22 is And the same surface coincides with the position of the boundary line t between the tapered surfaces 2b and 4b from the insertion end pressing surface of the face plate 12;
The insertion ring 4 is fitted into each of the claws 22 so that the rear end surface thereof comes into contact with the rising surface of the step portion 27, and each of the claws 22 is pressed against the outer peripheral surface of the insertion ring 4 by the urging force of the elastic body 25. A holding ring for holding the insertion ring.

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