JP2000240888A - Corrosion protective core structure of pipe end and fixing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide corrosion protective structure of a pipe coupling end part and a technique therefor to facilitate interjoining and provide superior workability, in a coupling structure wherein a cut pipe is used for a laying work at a site. SOLUTION: This corrosion protective core structure comprises a corrosion protective core 2, having necessary elasticity and fixed with a pressure at a pipe end face and an inner or an outer surface in the vicinity thereof, and a fixed ring 3 prevented from uncoupling and movement by energizing from the inside and the outside of the corrosion protective core 2. The fixed ring 3 is corrosion resistant, and one end 31 of a one-division inclinably intercouples buckles 33 which has juxtaposing chevron protrusions 32 protruding to the inner peripheral side and the other end 34 side having the same number of square holes 35, in which the respective chevron protrusions are fitted, and the two ends are engaged with each other with tension regulated to a desired state, and the corrosion protective core 2 is fixed. A corrosion protective cover is interrupted from contact with an external part and blocks the occurrence of rusting, and the two ends of the fixed ring 3 are locked in an overlapped state while tensile strength is increased through a lever action applied throver the whole periphery, whereby the whole of the inner peripheral surface of the corrosion protective core is uniformly pressed, caused by a tension force being always strong and constant fixing action being kept.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe joint for a cast iron pipe which is buried underground to form a pipe for water supply, in particular, not for connection between standard cast iron pipes but for dimension adjustment at the time of laying on site. The present invention relates to a corrosion prevention structure for a pipe joint end including a cut pipe generated when a cast iron pipe is cut in the middle.

[0002]

2. Description of the Related Art Cast iron pipes are provided with an anticorrosion function entirely by coating the outer surface and inner lining, and are laid underground and surrounded by moisture and other corrosive atmospheres contained in earth and sand that are in contact with the outer peripheral surface of the pipe. Even in contact with running water, it is protected so that corrosion does not easily progress. Therefore, as in the case of ordinary laying work, if the insertion port of another cast iron pipe is inserted into the socket of the cast iron pipe, and it is joined to each other in a water-sealed state with an appropriate water-stopping packing etc., it is almost complete There is no opportunity for water to penetrate into the water, and there is no concern about delivering good quality drinking water to consumers.

[0003] However, the laying of pipes does not always end only with the joining of cast iron pipes of fixed dimensions. In most laying works, it is rare that the last joint point of the construction section ends with a fixed size of the cast iron pipe, and the work area where the cast iron pipe cut halfway to the specified length has a half length Is a normal mode.

[0004] The cut pipe cut on site on the way due to construction work, at least at the cut end, the anticorrosive paint is shaved off,
When the pipeline is laid underground and exposed to a corrosive atmosphere, the exposed cast iron surface becomes a weak point subject to intensive corrosive action. Regardless of how the other surfaces are protected by the anticorrosion function, if there is a weak point to which the metal surface is exposed even in one place, the corrosion protection as a whole is completely lost, corrosion concentrates, and rusting parts are rapidly formed. It is more likely to grow into a cast nodule and generate red water.

At present, it is inevitable to cut the ductile cast iron pipe to a desired size and adjust the size at the site. Therefore, it is a matter of course that a means for ensuring the corrosion resistance of the cut end face is required. is there. Most primitively, there is a construction method to reapply the anticorrosion paint on the exposed surface of the end face of the incision pipe to restore the anticorrosion function, but in addition, attach a resin rust prevention cover to the end face of the incision pipe, Examples of covering the surface of the exposed cast iron to recover the anticorrosion function have been implemented.

FIG. 6A and FIG.
In the prior art presented in Japanese Patent Application Publication No. 5 (1994), the pipe to be connected is a standard-shaped receptacle as can be seen from FIG. (B), and the tip of the cut pipe is inserted into this receptacle as an insertion port. Assumes joining. The cylindrical body 101 having a diameter slightly smaller than the inner diameter of the target pipe is an annular fin 1 continuous in the circumferential direction.
02 are provided at regular intervals in the axial direction, and a sealing member 104 made of an elastic rubber material is provided with an annular ridge 103 serving as a stopper at the center, and a continuous incision is made in the inner surface of the sealing member 104 in the axial direction. The gist is a composite layer in which a metal cylinder 105 having a portion is coaxially and integrally fitted. The elastic deformation of the flexible sealing member 104 and the metal cylinder 1 supporting the back
The idea is that the deformation allowed by the incision cut in 05 absorbs the variation in the inner diameter due to the tolerance of the pipe, and the weak point of the rubber material is complemented by the strength of the metal tube fitted behind.

As another prior art, there has been proposed a series of systems in which an anticorrosion core is fitted only around the cut end (tube end face) of a cut tube to be engaged to protect the surface. For example, actual Kaihei 7
FIG. 7 shows an anticorrosion ring 200 for a tubular body according to No. 22198.
And a rubber-based adhesive 2 on the side of the inwardly projecting piece 202 facing the tube body.
03 is provided. JP-A-7-139686
In the anticorrosion cap 300, the cylindrical portion 301 inserted into the inner surface of the pipe as shown in FIG.
2 and an annular groove 303 is formed in the cylindrical portion 301 so that a stopper ring 3 which can be freely opened in the circumferential direction is provided.
4 shows a method of fitting by fixing.

[0008] As a prior art in which this method is improved, an anticorrosion cap 400 disclosed in JP-A-7-190287 is disclosed in FIG.
The stopper ring 402 which can be split and attached to the inner periphery of the cylindrical portion 401 of the cap body has long holes 403 at both ends in the circumferential direction. When the stopper ring 402 is attached, the diameter of the stopper ring 402 is reduced. This state is maintained by inserting the hook pins 404 after overlapping the long holes 403 with each other,
After inserting the hook pin 404 into a predetermined position, the diameter of the stopper ring 402 is released by releasing the hook pin 404.

[0009]

Among the prior arts exemplified here, in the case of repainting on site, the preparation and application of the coating material are not performed by a coating expert, but the workability and coating surface There is no shortage of quality concerns.
In addition, since the construction may be a pipe laying construction in a cold district or in a severe winter, it is not uncommon for the factor to spend a long time for drying after painting and to reduce the workability.

[0010] In particular, it is difficult to apply paint to the edge portion newly derived by the cut pipe, and it is difficult to deny the concern that the anticorrosive performance is deteriorated as compared with the quality managed under the mass production system in the factory. In addition, when applying a seismic pipe joint, the lock ring fitted to the socket and the slope of the insertion port are usually inserted to a predetermined position while being in contact with each other. However, this does not mean that there is no danger of peeling off due to abrasion and losing a sufficient anticorrosion function.

On the other hand, if a dedicated anticorrosion core is applied as shown in FIG. 6, the low reliability associated with the manual operation is surely improved. However, having a labyrinth seal on the outer surface of the core like this,
The method of inserting into the inner surface of the pipe to prevent water contact with the pipe end face is as follows:
The insertion of the anticorrosion core does not prevent the disadvantage that the cross-sectional area of water passage decreases and the pressure loss increases. In addition, when applied to a pipe having a large diameter, the unit price of the anticorrosion core rises and a drawback that causes a cost increase cannot be overlooked.

Although the prior art shown in FIG. 7 has a simple structure in which a resin ring is simply attached with a rubber-based adhesive, the ring may easily fall off due to bending of the tube or aging of the adhesive. Isn't it? Further, the application of the stopper ring of FIG. 8 which seems to make up for this drawback and the prior art of FIG. 9 which has further improved this are a stopper ring which can be split open, and the anticorrosion cap is held down from the inner surface and fixed. However, since it is a method that depends only on the spring force of the stopper ring fitted inside in the free state, the spring force due to material metal fatigue during long-term use for several decades Isn't it possible to wipe out the fear that the fixing force of the anticorrosion cap will be rapidly lost due to the decrease directly?

[0013] In order to solve the above-mentioned problems, the present invention provides a joint structure using cut pipes for laying work on site, which is easy to join with each other and has an anticorrosion structure at the end of a pipe joint with excellent workability. The purpose is to provide the method.

[0014]

According to the present invention, there is provided an anticorrosion core structure for a pipe end, comprising: a pipe end face, an inner peripheral face following the pipe end face, and an outer peripheral face for protecting a cut pipe and a metal ground portion exposed by tapering. An anticorrosion core 2 which has a structure that covers a part of the surface and has a required elasticity and is pressed against a part of a tube end surface 11, an inner peripheral surface 12, and a part of an outer peripheral surface 13, and an inner peripheral portion 22 of the anticorrosion core 2. And a fixing ring 3 for urging the inner peripheral surface 21 from the inner peripheral surface to the outer peripheral side to prevent detachment and movement. The fixing ring 3 is formed of a corrosion-resistant, open-cut, annular band. A buckle 33 in which a plurality of chevron projections 32 projecting inwardly are arranged in the circumferential direction is connected to be able to tilt freely,
On the side, the anticorrosion core 2 is fixed so that an appropriate crimping force can be obtained in accordance with the inner diameter tolerance by engaging the square holes 35 in which the chevron projections 32 can be fitted in parallel in the circumferential direction at the same pitch. Solved the problem.

In this structure, when the seismic joint structure in which the insertion ring 4 is fitted on the outer peripheral surface 13 of the cut pipe 1 is used, the outer peripheral surface 41 of the insert ring 4 and the outer peripheral surface of the cut pipe formed by the inclined surface are used. A preferred embodiment is to cover the tube 13, the tube end surface 11, and the inner peripheral surface 12 with an integral anticorrosion core 2 and fix the same with a fixing ring 3. Also, at least two ridges 37 are provided on the outer peripheral side of the fixing ring 3 in the circumferential direction to press the inner peripheral surface 21 of the inner peripheral portion 22 of the anticorrosion core 2 evenly from the entire circumferential direction to be in a crimped state. An embodiment in which is further enhanced is desirable.

As a method of fixing this structure, the anticorrosion core 2 having necessary elasticity is fitted to the cut tube 1 so as to cover and adhere to the tube end surface 11, the inner peripheral surface 12, and the outer peripheral surface 13. Attaching the fixing ring 3 made of a 10% annular band that is open to corrosion resistance to the inner peripheral surface 21 of the inner peripheral portion 22 of the anticorrosion core 2,
The buckle 33 connected at one end of the fixing ring 3 is rotated inward from the hinge 36 of the connecting portion to engage with the other end 34 of the fixing ring, and the buckle 33 is turned over with the hinge 36 as a fulcrum, and The two ends reinforced by the principle are overlapped by the stretching force, and the angled projection 32 on one end 31 is fitted and locked in the square hole 35 on the other end 34 side, and the inner peripheral portion 22 of the anticorrosion core 2 is in a necessary tension state. It is necessary to press and fix the inner peripheral surface 21 from the entire circumference. It is more preferable to adopt a structure in which the buckle 33 is fixed in a locked state.

In the anticorrosion structure according to the present invention, in addition to the end face 11 of the cut pipe generated for adjusting the pipe length on site, if it is a seismic joint, it is cut with an inclination so that the joint can be smoothly performed. The cutting surface at the end of the insertion opening formed by the outer peripheral surface 13, that is, the uncoated surface from which the anticorrosive paint applied during pipe production has been scraped off, and the entire outer peripheral surface of the insertion opening ring 4 are integrally formed with an anticorrosion core. 2 to prevent rusting by cutting off contact with the outside. The anticorrosion core 2 is made of resin or rubber having optimal elasticity. In particular, in the case of rubber, since it is black, which is the same color as a metal tube or a cast iron tube, it is difficult to determine whether or not it is attached. Therefore, by coloring the rubber in a color different from that of the metal pipe or the cast iron pipe, it is possible to prevent forgetting to attach the joint at the time of joining. Further, since the outer peripheral surface of the non-painted surface of the cutting tube 1 and the outer peripheral surface of the insertion ring fitted to form the earthquake-resistant structure are entirely covered and mounted over the entire periphery, water is prevented from entering from the end surface, The anticorrosion performance can be greatly improved even at an edge portion which is difficult to repaint with the anticorrosion paint.

Further, in the case of a pipe joint having an earthquake-resistant structure, even when the lock ring attached to the inner peripheral surface of the receiving port, which is inevitably generated during construction, comes into contact with the inclined surface of the outer periphery of the insertion port, it is possible to sufficiently withstand this and peel off. Therefore, there is no possibility that the anticorrosion property is impaired. However, to guarantee this feature,
The anticorrosion core attached to the inclined surface of the insertion opening must be manufactured by selecting a material having high tear resistance.

Even when unbalanced vibrations, vibrations, and swings act on the pipe line and pull-out force, compression force, and torsion force are applied to the joint, the anticorrosion core covering the unpainted surface of the cut pipe is prevented from coming off. It is a feature of the operation that it is strongly constrained to keep the corrosion resistance unchanged. In the prior art fixing ring (stopper ring), the annular band that can be split is simply opened to the inner peripheral surface of the anticorrosion core (anticorrosion cap) in a free state. Although it depended only on the characteristics, in the present invention, both ends of the fixing ring are overlapped while applying an expanding force enhanced by a roller action developed around a hinge of a buckle connected at one end of the fixing ring over the entire circumference. After locking, the entire inner peripheral surface of the anticorrosion core is evenly pressed to maintain the same fixing action.

In addition, the pressing force of the fixing ring 3 against the inner surface of the pipe sufficiently absorbs the tolerance of the inner diameter recognized between the pipes having the same diameter and the allowable dimensional error of the anticorrosion core 2 itself, so that the unit pressure is always constant. The fitting position between the angled projections 32 of the buckle and the square holes 35 can be shifted to adjust the expansion force to an optimum expansion force according to the inner circumferential length so that the inner circumferential surface of the pipe is uniformly loaded by the pressure.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1A is a partial vertical front view showing an embodiment of the present invention, and FIG. 1B is a partial vertical front view showing an embodiment of the present invention. In FIG. 1 (A), reference numeral 23 denotes a thick-walled portion which is provided on the inner peripheral portion 22 from the pipe end of the cut tube 1 and is a stepped portion. In FIG. 1B, reference numeral 23 denotes a thick portion provided on the inner peripheral portion 22 at the end of the cut tube 1 and serving as a step. The thick portion 23 functions to prevent the fixing ring 3 from shifting. Fig. 1 shows one of the insertion ports that forms an earthquake-resistant joint called NS joint in the Japan Water Works Association Standard. As described above, the insertion port of a cut pipe that cuts a standard-size standard pipe for the purpose of laying a pipeline. Show the side. However, it is not limited to the cut pipe, and may be a standard-size fixed-length pipe insertion port. Also, a pipe coupling of another type other than the NS coupling (a normal type having a non-seismic structure without an insertion ring, for example, FIGS. 7 and 8) Needless to say, it can be applied to

The cut end of the cut tube 1 forms a tube end face 11,
Since this embodiment has an earthquake-resistant structure, the insertion ring 4 for preventing separation is inserted and fitted so as to protrude onto the outer peripheral surface of the opening, and the vicinity of the distal end of the outer peripheral surface 13 is processed so that the joint is smooth. It has a gentle slope. Outer peripheral surface 41 of insertion ring 4, outer peripheral surface 13 of cut tube, tube end surface 11, inner peripheral surface 12
Is covered and fitted over the entire circumference with a corrosion-resistant core 2 made of rubber or resin and having a desired elasticity. When the material of the anticorrosion core 2 is rubber, the hardness of the rubber is 50 according to a durometer hardness test specified in JIS K 6253-5.
Approximately -80 corresponds to the optimal elasticity. A rubber material outside this hardness range may be too soft or too hard to fit into the insertion hole smoothly.

Since the outer peripheral surface of the anticorrosion core 2 is elastically pressed against the outer peripheral surface of the insertion port, the frictional force generated when the water-stop rubber ring slides when the pipes are joined, and the inner surface of the receptacle due to bending. The anticorrosion core 2 does not separate from the pipe end even if it encounters a frictional force caused by contact with the pipe. The fixing ring 3 presses the anticorrosion core 2 from the inner peripheral surface side to the outer peripheral side and maintains the immovable position of the anticorrosion core 2 from falling off due to water flow, and from being twisted or loosened by external force during vibration or vibration. Retaining ring 3
Are shown in FIGS. 2 to 5. FIG. 2 shows the fixing ring 3
FIG. 4 is a perspective view showing a cross-section taken in parallel with the pipe axis direction of the cutting pipe, and two annular ridges 37 projecting on the outer peripheral surface at a distance from a corrosion-resistant metal material are provided around the annular band. As a result, the rigidity of the ring itself is increased, and the effect of further strengthening the pressure of the anticorrosion core 2 against the inner peripheral surface 12 of the cut tube 1 is exhibited.

FIG. 3 is a partial sectional view showing a state in which the anticorrosion core 2 is fitted to the vicinity of the pipe end face 11 of the cut pipe 1 and the fixing ring 3 is set on the inner peripheral surface 21 of the inner peripheral portion 22 of the anticorrosion core 2. In addition, a buckle 33 in which several rows of chevron projections 32 are arranged is connected to one end 31 of the fixing ring 3, and the buckle 33 is set to be bent at a hinge 36 at the position shown in FIG. 4. Since the fixing ring itself is an open-ended split annular band made of an elastic corrosion-resistant stainless steel strip or the like, even in this state, the anticorrosion core is pressed and pressed against the inner peripheral surface of the cut pipe.

The position shown in FIG. 4 schematically shows a posture in which the other end 34 of the fixing ring 3 which has been a free end is locked to one position of the chevron 32 of the buckle 33. From this state, the buckle 33 is further moved. When the hinge 36 is used as a fulcrum to bend in the direction of the arrow in the figure, the rotational force is increased by the principle of leverage and converted into an expanding force that extends the entire annular band, and as shown in FIG. In the state of being stacked on the top 34, the chevron projection 32 and the square hole 35 are fitted to each other to exhibit a robust joining action. The tightening action can be appropriately set in consideration of the type of the pipe to be joined, such as the diameter of the pipe, the water pressure in use, and the like, and the angled projection 32 and the square hole 35 can be set according to the tolerance of the same type of pipe itself. It goes without saying that the change partner is appropriately selected to absorb the fluctuation. However, it is necessary that at least the respective pitches of the chevron projections 32 and the square holes 35 are perfectly matched so that a mating partner to be easily fitted can be collectively selected in the circumferential direction.

FIG. 10 shows another embodiment of the present invention.
A locking portion 38 bent downward is provided over a range having both side surfaces of the tip portion of the buckle 33, and the corresponding both side surfaces of the tip portion of the other end 34 are bent upward to form the locking portion 3.
This is a condition in which a locking portion 39 for locking to 8 is provided. There is an advantage that the locking of the locking portions 38 and 39 makes the locking of the one end 31 and the other end 34 more reliable and the fixing action is strengthened.

[0027]

As described above, the present invention is particularly effective when joining to a receiving port using a cut pipe generated in the on-site laying work of a pipeline, and when applying a joint for earthquake resistance. The non-painted portion that occurs in a wider area is covered with the anticorrosion cover, and the newly exposed metal surface (cut surface) does not become a weak point of the anticorrosion structure. Since no member is inserted on the inner peripheral surface side of the insertion port as in the prior art (FIG. 6), the problem of pressure loss does not occur without reducing the inner diameter of the pipe. Even if the joint part expands or contracts due to ground deformation after pipe joining, the anticorrosion cover moves with the insertion ring, so that the anticorrosion function is not affected at all. Since the tension of the fixing ring that presses and fixes the anticorrosion cover from the inner surface can be adjusted freely, the dimensional tolerance allowed for the inner diameter can be absorbed, the construction can be easily performed, and the anticorrosion cover can be tightly fitted to the end of the insertion port and blocked. This contributes to further improvement of the aqueous solution.

In particular, the feature of the present invention is that the function of preventing detachment is high due to the stronger restraining force of the fixing ring as compared with the conventional anti-corrosion cover and the like, and external force such as vibration, vibration and impact is applied to the pipeline. Also, the function of reliably preventing frequent replacement of water at the pipe end and preventing the generation of red water for a long period of time is maintained. Since the fixing ring is made of a corrosion-resistant elastic material, for example, stainless steel strip, even if it is indirectly connected with water for a long time, the deterioration of the function due to corrosion does not appear, and the cut pipe, anticorrosion core and fixing ring are integrated under appropriate tension. It forms an anti-corrosion structure which is laminated in order to effectively serve as a conduit.

Further, the cut pipe is often generated at the final stage of the laying work of the pipeline, but the procedure for installing the anticorrosion structure of the present invention is simple and easy, and does not assume the special skill of the operator.
There is no variation in quality due to individual differences. Jigs and tools are sufficient with simple hand-held items, and robust and water-tight joints can be easily installed in the field, and the effect of maintaining excellent characteristics is far superior to conventional technology. .

[Brief description of the drawings]

FIG. 1 is a partial longitudinal front view showing an embodiment of the present invention (A).
It is a partial vertical front view (B) which shows another embodiment.

FIG. 2 is a perspective view including a cross section of a fixing ring.

FIG. 3 is a partially longitudinal sectional front view showing a mounting state before locking of a fixing ring.

FIG. 4 is a cross-sectional view taken along the line AA in FIG. 5, schematically showing a method of locking the fixing ring.

FIG. 5 is a partially longitudinal front view showing a mounted state after locking of a fixing ring.

FIG. 6 is a longitudinal sectional front view (A) of the prior art and a partial longitudinal sectional front view (B) of the embodiment.

FIG. 7 is a partial longitudinal front view (A) of another conventional technique and an enlarged view of a main part thereof (B).

FIG. 8 is a partially longitudinal front view of still another conventional technique.

FIG. 9 is a side view (A) and a perspective view (B) of still another conventional technique.

FIG. 10 is a plan view (A) showing another embodiment of the present invention, a BB sectional view (B) and a CC sectional view (C) of the same figure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cut pipe 2 Corrosion protection core 3 Fixing ring 4 Insertion ring 11 Pipe end face 12 Inner circumference 13 Outer circumference 21 Inner circumference of corrosion protection core 22 Inner circumference of corrosion protection core 31 One end 32 Angle projection 33 Buckle 34 Other end 35 Square hole 36 Hinge 37 Protrusion 38 Lock section 39 Lock section

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Yoshihiko Yamamoto, Inventor 1-12-19 Kitahorie, Nishi-ku, Osaka-shi, Osaka Inside Kurimoto Iron Works Co., Ltd. (72) Yoshiki Okamoto 1-1-12 Kitahorie, Nishi-ku, Osaka-shi, Osaka No. 19 Inside Kurimoto Ironworks Co., Ltd. (72) Inventor Yasuhiro Ikeuchi 4-5-2, Minamihorie, Nishi-ku, Osaka City, Osaka Prefecture Togawa Rubber Co., Ltd. 834 No. 1 Daimon Tokushima Rubber Tokushima Market Plant F-term (reference) 3H024 CA03 EA04 EC15 ED01 EE03 EF06 EF20

Claims (4)

[Claims] An anticorrosion core structure for a pipe end covering a pipe end face and a part of an inner peripheral surface and an outer peripheral face following the pipe end face to protect the pipe end of a metal pipe such as a cut pipe, and has elasticity. The anticorrosion core 2 that is crimped to a part of the pipe end surface 11, the inner peripheral surface 12, and the outer peripheral surface 13 and the inner peripheral surface 22 of the inner peripheral portion 22 of the anticorrosive core 2 is urged outward to prevent detachment and movement. The fixing ring 3 is formed of a corrosion-resistant, open-cut one-piece annular band, and one end 31 has a plurality of chevron-shaped projections 32 projecting inwardly in a circumferential direction. Buckle 33
The other end 34 side is divided in the circumferential direction at the same pitch with the same number of square holes 35 to which the chevron 32 can be fitted, and the two ends are engaged in a desired tension state. An anticorrosion core structure for a pipe end, wherein the anticorrosion core 2 is fixed together. 2. The outer peripheral surface 1 of the cutting tube 1 according to claim 1.
In the case of a seismic joint structure in which the insertion ring 4 is fitted on the upper surface 3, the outer peripheral surface 41 of the insertion ring 4, the outer peripheral surface 13 of the cut pipe formed by the inclined surface, the pipe end surface 11, and the inner peripheral surface 12 are formed. An anticorrosion core structure for a pipe end, which is covered with an integral anticorrosion core 2 and fixed with a fixing ring 3. 3. The inner peripheral surface 21 of the inner peripheral portion 22 of the anticorrosion core 2 according to claim 1 or 2, wherein at least two ridges 37 project in the circumferential direction on the outer peripheral side of the fixing ring. An anticorrosion core structure for a pipe end, wherein the crimped state is further strengthened by uniformly pressing from a direction. 4. An anticorrosion core for a pipe end for fitting and fixing an anticorrosion core 2 to a pipe end face and a part of an inner peripheral face and an outer peripheral face following the pipe end face in order to protect a pipe end of a metal pipe such as a cut pipe. In the method of fixing the structure, the anticorrosion core 2 having the necessary elasticity is fitted so as to cover and adhere the pipe end face 11, the inner peripheral face 12, and the outer peripheral face 13 of the cut pipe 1, and is opened with corrosion resistance. A buckle 3 attached to the inner peripheral surface 21 of the inner peripheral portion 22 of the anticorrosion core 2 and connected to the fixing ring 3
3 is rotated inward from the hinge 36 to rotate the other end 3 of the fixing ring.
4 and the buckle 33 with the hinge 36 as a fulcrum.
Is overturned by the extension force strengthened by the principle of the roller, and the plurality of chevron projections 32 on one end 31 are fitted and locked into the plurality of square holes 35 on the other end 34 side, respectively. A method of fixing an anticorrosion core structure for a pipe end, wherein the inner peripheral surface 21 of an inner peripheral portion 22 of the anticorrosion core 2 is pressed and fixed from all around in the state.