JP4046646B2 - Method for forming insertion port protrusion and insertion port ring holding device used therefor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of forming a protrusion on the outer peripheral surface of the insertion port constituting a pipe joint with an expansion / contraction function in which the insertion port of the other tube is inserted into the receiving port of one tube, and a holding device for the insertion port ring 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 the connection is made at one end of the cast iron pipe. This is 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 the pipe joint structure, even when an unsteady external force hits the pipeline due to an earthquake or the like in recent years, the pipe joint has been strongly required to have an earthquake resistance that absorbs and relaxes the external force. The one with a telescopic function came to be adopted.
[0003]
As the pipe joint with the expansion / contraction function, for example, there is an NS type joint shown in FIG. 9, and this joint forms a groove 3a around the inner surface of the receiving port 1a of one pipe 1, and a lock ring 3 is formed in the groove 3a. The outer surface of the end of the insertion port 2a of the other tube 2 is formed into a tapered surface 2b having a downward slope toward the tip, and the insertion port 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 the outer peripheral surface of the protrusion 4 is a tapered surface having the same inclination that is continuous with the tapered surface 2b, and the other tube 2 is inserted into the receiving port 1a of the one tube 1. The opening 2a is configured to be inserted through the protrusion 4 over the lock ring 3 (in the center chain line state of the insertion opening 2a). In the figure, 5 is a lining layer, and 6 is a packing (rubber ring).
[0004]
In the NS type joint, when an unsteady external force directly hits the pipe line due to an earthquake or the like, the insertion port 2a until the tip of the insertion port 2a comes into contact with the inner surface step portion 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, and absorbs the external force and prevents the insertion port 2a from being pulled out.
[0005]
In a pipe joint in which this kind of insertion port 2a is provided with a projection 4, the method of forming the projection 4 is to form the tube 1 and 2 (insertion port 2a) at the same time, and press-fitting the insertion port ring. There is one that fixes the insertion port ring 4 to the insertion port 2a by welding or the like.
[0006]
As shown in FIGS. 5 (a) to 5 (b), the method of forming the protrusion by the insertion port ring 4 is such that the rear end surface 4c of the insertion port ring 4 is flush with the end surface of the end portion of the insertion port 2a. Then, as shown in FIGS. 6B and 8B, the outer peripheral surfaces of the end portions of the insertion port ring 4 and the insertion port 2a are tapered surfaces 4b and 2b by a cutting blade 30 having an inclined blade surface. Is cutting. At this time, as shown in FIG. 7, there is a case where the outer periphery of the insertion port end is R-cut c. In the figure, the chain line portion is a cutting portion (see Patent Documents 1 and 2).
[0007]
[Patent Document 1]
JP-A-9-178059 [Patent Document 2]
Japanese Patent Laid-Open No. 10-153285
[Problems to be solved by the invention]
The insertion ring (protrusion) 4 is specified by the standard to use a material having high mechanical properties with respect to the tubes 1 and 2, for example, FCD 420 or more on the tubes 1 and 2. 4 uses FCD600-3 or higher.
[0009]
For this reason, as can be understood from FIG. 6 (b), the conventional method of forming the protrusion 4 of the insertion slot 2a cuts nearly half of the hard insertion slot ring 4, so that its workability is poor. In addition, the life of the cutting tool is short.
[0010]
Moreover, when performing the R-cut c of the outer periphery of the insertion port end, conventionally, as shown in FIG. 8B, after the tapered surface 2b is formed, the R-cut operation is performed, and the processing is performed. It is done by a grinder and the workability is poor.
[0011]
This invention makes it a subject to reduce the cutting area | region of an insertion port ring.
[0012]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention can be inserted from the boundary between the tapered surface of the insertion port end and the insertion port ring on the end side (the left side of the front end side in FIG. 6), as can be understood from FIG. Paying attention to the fact that the mouth ring portion is entirely cut off (internal and external surfaces), the insertion ring is press-fitted and fixed to the position of the boundary between the two tapered surfaces, and then the insertion ring and The taper surface is formed by cutting the insertion port end.
[0013]
In this way, the entire insertion opening ring is not cut, and a minimum cutting operation is sufficient, so the workability is good. In addition, the insertion ring can be narrower than the conventional one, and the machining cost is reduced, and the cost is reduced accordingly.
[0014]
DETAILED DESCRIPTION OF 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 downward toward the tip. The protrusion 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 having the same slope continuous with the tapered surface. And a method of forming the projection of the insertion port in a pipe joint structure in which the insertion port of the other tube is inserted into the receiving port of the one tube over the lock ring. The insertion port ring is press-fitted and fixed to the end of the insertion port until the rear end surface is located at the boundary between the two tapered surfaces, and then the insertion port ring and the insertion port end are cut to form the tapered surface. A configuration may be employed.
[0015]
At the time of cutting the tapered surface, it is preferable to make a round cut on the outer peripheral edge of the insertion port end. Since this R cut is only for cutting the tube body, even a thin blade is sufficient in strength. For example, as shown in FIG. By means of the tool, it is possible to make a round cut on the outer peripheral edge of the end of the insertion port end simultaneously with the cutting of the tapered surface of the insertion port end and the insertion port ring.
[0016]
In these molding methods, when the insertion port ring is press-fitted into the insertion port, a device for holding the insertion port ring may be adopted as appropriate. For example, the insertion of a face plate against which the insertion port end is pressed is possible. A plurality of claws that advance and retreat in the radial direction from the axial center are provided at equal intervals around the axial center of the mouth, and each of the claws is urged toward the axial center by an elastic body, A stepped portion that rises toward the center is formed, and the rising surfaces of the stepped portions of the claws are in the same plane around the axis, and the same surface extends from the pressing surface at the insertion port end of the face plate. It is aligned with the position of the boundary line of the surface, and the insertion ring is inserted into each claw so that the rear end surface is in contact with the rising surface of the step portion, and each nail is inserted by the urging force of the elastic body. Holds the insertion ring by pressing against the outer periphery of the ring To adopt a configuration that.
[0017]
In this holding device, the rising surface of the stepped portion of each claw coincides with the position of the boundary line between both tapered surfaces from the insertion port end pressing surface of the face plate, the insertion ring is inserted into each claw, and the rear end surface is stepped. Since the end of the insertion port is pressed into the insertion ring and pressed against the pressing surface of the face plate, the insertion port is pressed and pushed in through the elastic body of each nail. The insertion port ring is centered, and the insertion port ring is press-fitted and fixed to the end of the insertion port with the rear end face located at the boundary between both tapered surfaces. For this reason, formation of said insertion port protrusion can be performed smoothly and accurately.
[0018]
【Example】
1 to 4 show an embodiment of the present invention. In this embodiment, as shown in FIG. 1, a fixed platen 11 is provided at the tip of a piston rod 10 of a hydraulic cylinder as in the prior art. 11, the face plate 12 is bolted, and the face plate 12 can advance and retreat on the same line with respect to the receiving face plate 13 by a hydraulic cylinder. Fixing of the face plate 12 and the fixed platen 11 is optional, for example, as shown by a chain line in FIG. The face plate 12 is provided with a holding device 20 for the insertion port ring 4. The cast iron pipe 1 receives the receiving port 1a in contact with the face plate 13 and is held horizontally by appropriate means, and in the support 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 into the insertion port ring 4 fitted in advance to the holding device 20, and the insertion port ring 4 is press-fitted into the insertion port 2a.
[0019]
The holding device 20 for the insertion ring 4 includes a press plate 21 and a claw 22 which are divided into four parts. The press plate 21 is bolted to the face plate 12, and a housing 23 of the claw 22 is interposed between the press plates 21. It is inserted. The housing 23 is movable 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 via the radial holes (not shown) formed in the face plate 12, and the housing 23 can be surfaced by appropriately selecting the position of the bolts in the long holes. The board 12 (presser plate 21) is fixed to a required position in the radial direction. At this time, the head of the bolt may be buried in the face plate 12 or may protrude. Like the housing 23, the claw 22 can move in the radial direction by a rail / groove structure, and its plunger 24 is inserted into and retracted into the sleeve 28 of the housing 23 and is pushed by a spring 25. The claw 22 is biased toward the center by the spring 25. The biasing force is adjusted by the screwing degree of the bolt 26.
[0020]
The inner surface 22a of the claw 22 is a taper surface having a downward slope from the outer end toward the axis r, and a step portion 27 is formed at the end, and the insertion ring 4 is guided by the taper surface 22a. The stepped portion 27 is fitted into the nail 22 and supported. The insertion ring 4 has a width that is two-thirds that of the conventional one (see FIG. 8). Further, the distance a (position: see FIG. 1) of the stepped portion 27 from the surface of the face plate 12 is from the end surface of the insertion port 2a to the boundary line t of the outer peripheral surface and the tapered surfaces 2b, 4b of the protrusion 4. When the insertion port 2a is press-fitted into the insertion port ring 4 of the holding device 20, as shown in FIG. 4 (a) to FIG. 4 (b), the distance is set via the spring 25 of each claw 22. The insertion port ring 4 is centered according to the insertion of the insertion port 2a by advancing and retreating, and the insertion port ring 4 is pressed into the position (distance a) of the boundary line t of the insertion port 2a.
[0021]
After the insertion port 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 retracted from the insertion port 2a, and the cast iron pipe is moved to that state or another position Then, build-up welding is performed on the groove 4a of the insertion ring 4 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 portion of the round cut c is cut of the cast iron pipes 1 and 2 (insertion opening 2a), it can be smoothly cut by the tip portion 31 and a portion thereof is not lost. The build-up weld is made flush with the other outer peripheral surface by cutting.
[0022]
The embodiment is a case of NS type joint, but 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 slot 2a. Of course. In addition to the spring 25, an elastic body having the same action, for example, an air cylinder (damper) may be employed.
[0023]
【The invention's effect】
Since this invention reduced the cutting amount of the insertion slot ring as mentioned above, the workability | operativity improves.
[Brief description of the drawings]
FIG. 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. 6] Fig. 6 is a diagram showing the press-fitting action of the conventional insertion ring. [Fig. 6] Fig. 7 is an enlarged sectional view of the main part of the insertion port. [Fig. ] Cross-sectional view of the main part of NS type joint [Explanation of symbols]
1, 2 Cast iron pipe 1a Receiving port 2a Insert port 2b Insert port end outer peripheral tapered surface 3 Lock ring 4 Insert port ring (protrusion)
4b Insertion-ring ring taper surface 10 Hydraulic cylinder rod 11 Fixing plate 12 Face plate 13 Receiving surface plate 20 Insertion-ring holding device 21 Presser plate 22 Claw 25 Spring 30 Cutting blade 31 Cutting blade's R-cut portion c Ear-cut r Cast iron pipe Axis t boundary line

Claims (3)

A groove 3a is formed on the entire inner surface of the receiving port 1a of one tube 1, a lock ring 3 is fitted into the groove 3a, and the outer surface of the end of the insertion port 2a of the other tube 2 is tapered downward toward the tip. 2b, and the projection ring 4 is fixed to the outer periphery of the insertion port 2a at the rear end of the tapered surface 2b to form a projection, and the outer circumferential surface of the projection 4 has the same inclination as the taper surface 2b. In the pipe joint structure in which the insertion port 2a of the other tube 2 is inserted into the receiving port 1a of the one tube 1 and the protrusion 4 is inserted over the lock ring 3 into the receiving port 1a of the one tube 1. A method of forming the protrusion 4 of the insertion opening 2a,
The insertion port ring 4 is press-fitted and fixed to the end of the insertion port 2a until the rear end surface thereof is located at the boundary line t between the tapered surfaces 2b and 4b, and then the insertion port ring 4 and the insertion port end are cut. And forming the taper surfaces 2b and 4b. The method of forming an insertion port protrusion according to claim 1, wherein a radius cut c is applied to the outer peripheral edge of the insertion port end at the same time as the taper surface cutting of the insertion port end and the insertion ring 4. In the method of forming the insertion port protrusion 4 according to claim 1 or 2, when the insertion port ring 4 is press-fitted into the insertion port 2a, the device holds the insertion port ring 4.
A plurality of claws 22 that advance and retreat in the radial direction from the axial center r are provided at equal intervals around the axial center r of the insertion opening 2a of the face plate 12 to which the end of the insertion opening 2a is pressed. The stepped portion 27 rising toward the shaft center r is formed on the inner surface of each claw 22, and the rising surface of the stepped portion 27 of each claw 22 is formed on the shaft center. It is in the same shape around, and the same surface coincides with the position of the boundary line t between the tapered surfaces 2b and 4b from the insertion port end pressing surface of the face plate 12,
The claw 22 is inserted into the claw 22 and the mouth ring 4 is fitted so that the rear end surface thereof is in contact with the rising surface of the stepped portion 27, and the claw 22 is inserted and pressed against the outer peripheral surface of the cuff ring 4 by the biasing force of the elastic body 25. An insertion port ring holding device characterized by holding the insertion port ring 4.

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