JP2001280581A - Fixing structure of pipe end corrosion preventing core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain deterioration in close contactness of a corrosion preventing core. SOLUTION: A fixed ring 8 is provided over the whole circumference of the inner surface of cylindrical part inserted into an inner surface of a pipe end of a pipe end corrosion preventive core 7, and the core 7 is fixed to the pipe end with the cylindrical part which makes pressure welded with the inner surface of tube end by the ring 8. The ring 8 is cut at one portion in the circumferential direction, so as to be openable while both ends 8a, 8b thereof are fastened by blind rivets 20 by use of a connection piece 10. Holes 14, 11 of the piece 10 and the end 8a are provided at several pitches, respectively, while the former has a pitch shorter than that of the latter. This relates to between the main part and sub part of calipers, and when the ring 8 is widened in its diameter, the axes of the holes 11, 14 vary, and then with the holes 11, 14 whose axes are made identical both the ends 8a, 8b are widened with the rivets 20. Accordingly, tolerance for the inner diameter of pipe can be absorbed and effective pressure contact of the core 7 can be maintained for a long period of time by the ring 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for fixing a pipe end anticorrosion core at a metal pipe insertion port constituting a pipeline for water supply or the like, particularly when the metal pipe is cut in the middle of a metal pipe for dimensional adjustment at the time of laying. The present invention relates to a structure for fixing a tube end anticorrosion core at the end of a torsion tube (incision tube) generated.

[0002]

2. Description of the Related Art Conventionally, for example, when a ductile cast iron pipe is buried underground to lay a pipe, corrosion protection is performed by coating or lining the entire pipe, as shown in FIG.
It is general that the insertion port 2a of the succeeding pipe 2 is inserted into the receiving port 1a of the preceding pipe 1 and joined. At this time, as shown in the figure, in the NS type joint provided with earthquake resistance, the lock ring 3 is provided on the inner surface of the receiving port 1a via the rubber centering ring 3a, and as shown by the chain line in the figure, This lock ring 3
The insertion ring 4 gets over and the insertion opening 2a is inserted.
In the drawing, 4a is an annular fitting groove of the insertion ring 4, 5 is a packing, and 6 is a lining.

[0003] In laying this pipeline, it is not always necessary to always join only pipes of a fixed size (standard standard), but it is necessary to cut and join the pipes 2 to a predetermined length at a construction site. There are cases. When the pipe 2 is cut in the middle in this way, the coating is peeled off from the end face of the pipe, which becomes the cut surface, and the ground surface is exposed, so that the anticorrosion function is impaired and red water or the like is generated. Therefore, in general, an anticorrosion coating is applied again to the end face after the cut tube to prevent corrosion. However, in the case of re-coating, it takes a long time to dry in cold weather and the workability deteriorates. In addition, paint is hardly applied on the edges and the anticorrosion performance is inferior to factory painted products. In such places where running water does not stop completely, there is a problem that it is difficult to apply such as hard to apply.

[0004] Therefore, as a method other than applying the anticorrosion paint to the end face after the incision, there is a method of sealing the exposed portion by using an anticorrosion core 7 as shown in FIG.
The anticorrosion core 7 is made of a resin, rubber or the like having a certain degree of elasticity, and is fitted over the entire circumference so as to cover the end surface of the cut tube from the inner and outer surfaces of the insertion opening 2a, thereby preventing water from entering the end surface. In addition, the anticorrosion performance of the edge portion, which is difficult with the anticorrosion paint, is improved.

The NS type pipe has a tapered surface 2
b contacts the lock ring 3 at the time of joining the joint,
In the field construction, the anticorrosion paint may be peeled off and a sufficient anticorrosion effect may not be obtained. For this reason, covering the tapered surface 2b with the core 7 having high tear resistance is an effective anticorrosion means. Since the anticorrosion core 7 is made of an elastic body such as rubber, it is held by an elastic force. As a method for fixing the core more reliably, it is disclosed in JP-A-7-253189, and as shown in FIG. There is a type in which a fixing ring 8 that can be split open in one direction is fitted to the inner cylindrical portion of the anticorrosion core 7 and is fixed by the expanding force from the inner surface (see FIG. 4).
In FIG. 20, reference numeral 9 denotes an annular fitting groove of the fixing ring 8.

[0006]

However, since the fixing ring 8 fixes the anticorrosion core 7 only by the expanding force of the opening itself, if the fixing ring 8 is used for a long period of time, the material of the fixing ring 8 expands due to aging and the like. Radial force is attenuated, and there is a limit to maintaining the anticorrosion function, which causes a problem of low reliability.

SUMMARY OF THE INVENTION It is an object of the present invention to minimize the aging of the expanding force of the fixing ring.

[0008]

In order to solve the above-mentioned problems, the present invention provides a function of preventing a diameter reduction between both ends of a fixed ring. With this function, the degree of decay of the expanding force with time becomes slower as compared with the conventional one, regardless of whether the fixing ring is open or not.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As an embodiment of the present invention, a fixing ring is provided around the entire inner surface of a cylindrical portion inserted into the inner surface of a pipe end of a pipe end anticorrosion core, and the anticorrosion core is attached to the cylindrical portion. In the structure in which the fixing ring is pressed against the inner surface of the pipe end and fixed to the pipe end, the fixing ring is divided into one in the circumferential direction, and both ends of the fixing ring overlap with the inner surface of the pipe end anticorrosion core in a pressed state. A configuration in which a communication hole is formed, a blind rivet is inserted into the communication hole from the inside of the fixing ring, and both ends of the fixing ring are fastened by the blind rivet may be employed. In this configuration, both ends of the fixing ring are integrated by rivet fastening, and the function of preventing the diameter of the fixing ring from expanding is achieved.

According to another embodiment, in the above-mentioned embodiment, a connecting piece is passed between both ends without overlapping both ends of the fixing ring, and both ends are fastened via the connecting piece. obtain. That is, a fixing ring is provided around the entire inner surface of the cylindrical portion inserted into the inner surface of the tube end of the tube end anticorrosion core, and the anticorrosion core is pressed against the inner surface of the tube end by the fixing ring to form the pipe. In the structure fixed to the end, the fixing ring is divided by one in the circumferential direction, and at both ends, the fixing ring is overlapped with a connecting piece in a press-contact state on the inner surface of the pipe end anticorrosion core. A communication hole is formed between both ends, and a blind rivet is inserted into each of the communication holes from the inside of the fixing ring, and both ends of the fixing ring are fastened by the blind rivet via a coupling piece. And

In the embodiment in which both ends of the fixing ring are overlapped, a plurality of communication holes having the same size are formed at both ends of the fixing ring at equal pitches in the length direction of the fixing ring. The pitch of the communication holes at both ends is different, and a blind rivet may be inserted into the corresponding communication holes at both ends of the fixing ring and both ends may be fastened.

In the embodiment using the connecting piece, a plurality of communication holes having the same size are formed at one end of the fixing ring and the connecting piece at the same pitch in the longitudinal direction. The pitch of the communicating hole at the end and the communicating hole of the connecting piece is different, and a blind rivet is inserted into one end and the corresponding communicating hole of the connecting piece, and the connecting piece is fastened to the end. A configuration may be employed.

In the case where the pitches of these communication holes are different, both ends or one end and the connecting piece are based on the same function as the main scale and vernier scale of the caliper, and the manufacturing tolerance of the inner diameter of the pipe insertion port is used. Even if the gap of the split portion of the fixing ring changes, any of the communication holes can be riveted in a corresponding manner. That is, it is possible to sufficiently absorb the tolerance of the inner diameter of the pipe and to perform a strong fastening. At this time, the pitch of the communication holes is appropriately set in accordance with the degree of adjustment for the change of the split portion.

Here, the "same size" includes an error that does not impair absorption such as a tolerance based on the functions of the main scale and the vernier scale, and the "correspondence" of the communication hole is Not only when they are located on the same axis, but also when the rivets can be inserted into both communication holes and fastened without moving the both ends of the fixing ring and the connecting piece pressed against the anticorrosion core. Shall be considered. Further, the number of both communication holes on the main scale side and the vernier side may be the same number, but if the number of communication holes with a large pitch on the main scale side is increased, the length of each communication hole is formed, The adjustment range can be widened (FIG. 9
(See the chain diagram in (a)).

In the embodiment in which a plurality of communication holes having the same pitch are formed, both ends of the fixing ring, or one end of the fixing ring and the number of the communication holes of the connecting piece are equal in number, and the communication holes having a large pitch are formed. If the value obtained by multiplying the number obtained by subtracting one from the number by the pitch and the number obtained by multiplying the number of the communication holes having a small pitch by the pitch are set to be the same, one end of both communication holes can be obtained. If there is a deviation in length obtained by multiplying the pitch difference by the number of one of the communication holes from the state where the objects correspond, the one end of the communication hole having a small pitch is the one end having a large pitch. This corresponds to the next one, and from that state, the displacement is adjusted by the same action (see the embodiment of FIG. 9B).

In the embodiment using the connecting piece, the other end of the fixing ring and one of the connecting pieces are provided with:
A plurality of the communication holes for fastening the two are formed in the length direction of the fixing ring or the coupling piece, and the pitch of the communication holes is the pitch difference between the one end and the communication hole of the coupling piece and the length thereof. A configuration in which the length is multiplied by the smaller number of communication holes in the vertical direction (including the same number of communication holes) may be adopted.

According to this configuration, by selecting the communication hole of the other end or the connecting piece and changing the fastening position of the other end and the connecting piece, the one end and the connecting piece can be connected. The reference point of the communication hole changes, and the width corresponding to a change in the inner diameter of the pipe, such as a manufacturing tolerance, increases (see the examples of FIGS. 8A to 8C). Here, the length obtained by multiplying the pitch difference by the smaller number of the communication holes is that the adjustment width is determined by the number of the corresponding communication holes based on the deviation between the one end and the coupling piece. The corresponding number depends on the smaller number. For example, three and five are determined by the former three, and after the third communication hole corresponds, the reference point is shifted, This is to obtain the same function.

In each of the above embodiments, the pipe end anticorrosion core is provided with a recess for accommodating a projection from the fixing ring of the blind rivet so that the projection of the blind rivet does not press the anticorrosion core. Is preferred.

Further, instead of the blind rivet fastening, screw fastening may be used. At this time, the communication hole at the end of the fixing ring on the anticorrosion core side may be a screw hole, but it may be possible to fasten with a tap screw instead of the screw hole.

[0020]

FIG. 1 to FIG. 8 show an embodiment in which an anticorrosion core 7 is attached to the end of an NS type cut-out port 2a shown in FIGS. 19 and 20. Both ends 8a and 8b of the fixing ring 8 are fastened with the connecting piece 10 fixed with the rivet 20. The material of the fixing ring 8 and the connecting piece 10 is desirably a spring stainless material, but is not particularly limited to a material having no spring property. In addition, a shape memory alloy or a superelastic alloy can be used for the fixing ring 8, and these alloys are advantageous from the viewpoint of workability when the diameter of the tube 2 is small. That is, when the anticorrosion core is attached to a small-diameter pipe, it is difficult to reduce the diameter with a fixing ring made of stainless steel or the like, and the workability may deteriorate. Also, if you forcibly reduce the diameter, plastic deformation,
Rupture is also conceivable. In contrast, shape memory alloys are generally easy to deform, and at a certain temperature, a fixing ring of the shape memory alloy stored so as to expand the diameter to an optimal size for fixing the anticorrosion core can enter the inner surface of the anticorrosion core. After the diameter is reduced to the size and attached to the inner surface of the core, the core is heated to the above-mentioned temperature, returned to the original shape, and the core is fixed, whereby the work can be performed more smoothly. In addition, the superelastic effect means that even if it is greatly deformed at a temperature higher than the shape recovery temperature, it returns to the original shape again except for stress, and if it is a fixing ring of a superelastic alloy having this characteristic, If attached to the inner surface of the core at a temperature higher than the shape recovery temperature, its deformation is easy,
In addition, the core recovers its shape at room temperature without plastic deformation, and the core can be fixed.

One end of the fixing ring 8 has a length 9
Five holes 11 are formed at a mm pitch A ′, where A = 36 m
m), and the other end has a 3 mm pitch C ′ in the longitudinal direction.
Individual holes 12 are formed (C = 10 mm, see FIG. 7). An insertion hole (jig hole) 13 for the spring pliers P is formed inside the holes 11 and 12.
As shown in (a), the pliers P are inserted into the holes 13, and the diameter of the fixing ring 8 is enlarged and reduced by the pliers P. Five holes 14 having the same size as the holes 11 are formed in the connecting piece 10 at a pitch B ′ of 10 mm in the length direction thereof.
= 40 mm), and a fixing hole 15 having the same size as the hole 12 is formed at one side thereof. The distance between the fixing hole 15 and the left end hole 14 is, as shown in FIG. 20, in a state where there is no tolerance between the inner surface of the pipe and the groove 9 and the fixing ring 8 is simply fitted to the anticorrosion core 7 only by its elasticity. When the fixing hole 15 has the same axis as the center of the three holes 12, the left end hole 11 of the one end 8a and the left end hole 14 of the connecting piece 10 are set to have the same axis ( (FIG. 7). In addition, the fixing hole 15 can have the same axis as the left end of the three holes 12 (see FIG. 8). In this case, when the fixing ring 8 is fitted in the groove 9, there is no diameter reduction. Be sure to expand the diameter. Both ends 8a and 8 of the fixing ring 8 at these times
The gap b to the reference gap Y _0. Note that the reference gap Y
_{In the} case where there is no tolerance, ₀ may be set in a state where the anticorrosion core 7 in which the diameter of the fixing ring 8 is expanded by the spring pliers P is in a good pressure contact state.

If the connecting piece 10 and one end 8a of the fixing ring 8 are a vernier caliper and a vernier caliper, the holes 1
Due to the pitch difference between the holes 1 and 14, the holes 11 and 14 having the same axis change according to the degree of displacement between them. That is, in FIG. 8A, in a state where the center of the hole 15 and the center of the hole 12 on the left end are coincident (coaxial), one end 8a moves in the arrow direction as shown in FIG. 8B. When the diameter of the ring 8 is expanded (when the gap between both ends 8a and 8b becomes Y), for example, when the ring 8 is moved by 3 mm, the centers of the fourth holes 11 and 14 from the left coincide. Thus, 1 mm
Each time, the matching holes 11 and 14 change. For this reason, if the rivet 20 is inserted through the matching holes 11 and 14 and fastened, the expanded state is reliably maintained.

In the case where the hole 15 is shifted by 4 mm or more, as shown in FIG. 8C, if the hole 15 is made to coincide with the hole 12 on the right side, the hole 15 is shifted by 5 mm. The holes 11 and 14 coincide. If the hole 15 is displaced by 9 mm or more, and the hole 15 is further aligned with the hole 12 on the right end, similarly, any one of the holes 11 and 1
4 matches. Therefore, in this embodiment, the reference gap Y
It is possible to cope with the displacement from ₀ to the gap Y of 14 mm.

Based on this idea, by setting the pitches A ′ and B ′ of the holes 11 and 14 and their numbers and the number of holes 12 arbitrarily (see FIG. 7), the deviation from the reference gap Y ₀ can be reduced. It can be taken arbitrarily. Also, the reference gap Y ₀ is
Hole 15 is not holes 12 at both ends, if the time corresponding to the middle of the hole 12, reduced diameter or from the reference gap Y ₀ may correspond to both fixed state of enlarged diameter. One hole 12 and a plurality of holes 15 may be provided.

The blind rivet 20 shown in FIG. 6, which can be fastened from only one side, is used as the rivet. The blind rivet 20 includes a cylindrical rivet main body 21 and a drawing rod 22 inserted through the main body 21. As shown in FIG. 3A, holes 1 in fixing ring ends 8a and 8b are formed.
The ears 21a of the main body 21 are swelled by their heads 22a by inserting the rods 1 and 12 into the holes 14 and 15 of the connecting piece 10 and pulling the extraction rod 22 as shown in FIG.
The swelling portion 21a and the upper flange 21b clamp the fixing ring 8 and the coupling piece 10 and fasten them together. At this time, since the bulging portion 21a protrudes from the surface of the fixing ring 8, the portion corresponding to the holes 11 and 12 of the anticorrosion core 7 is the groove 1
6 is formed, and the bulging portion 21a (head 22a) is formed by the groove 16.
Should be stored. Thereby, the fixing ring 8 does not rise from the anticorrosion core 7 and the anticorrosion core 7 is not damaged. However, if there is no problem, the groove 16 can be omitted.

This embodiment has the above configuration.
Explaining the mounting operation of this embodiment, first, the fixing ring 8 is fitted into the groove 9 of the anticorrosion core 7, and the snap ring pliers P are inserted into the jig hole 13 to expand the diameter. This diameter expansion is such that the fixing ring 8 applies an appropriate pressure force to the anticorrosion core 7 to effectively prevent peeling.
The rivets 20 are inserted into the corresponding holes 11 and 14 and fastened. At this time, as shown in FIG.
The corresponding holes 11, 14 may be identified. That is, the gauge 25 cannot be inserted into both holes 11 and 14 if they do not correspond to each other as shown in FIG. It can be inserted and its correspondence can be confirmed. Also, as shown in FIGS.
14 are sequentially assigned numerical values such as 0 to 4 in the column direction, the gap Y after diameter expansion is measured, and the difference between the gap Y and the reference gap Y ₀ is calculated.
If the difference between the holes 11, 14 is, for example, 3 mm, the rivet 20 can be inserted into the holes 11, 14 having the numerical value 3. Instead of the spring pliers P, other tools such as a pin wrench, a giant vise, and the like may be employed.

As shown in FIG. 9, the number of holes 12 in the other end portion 8b of the fixing ring 8 may be one, and the number of holes 11, 14 may be arbitrarily set as described above such as ten in FIG. is there. Further, the number of both communication holes 11 and 14 on the main scale side and the vernier scale side is made the same number, and a value obtained by multiplying the number obtained by subtracting one from the number of communication holes 14 having a large pitch by the pitch, and a value having a small pitch If the number obtained by multiplying the number of communication holes 11 by the pitch is set to be the same, for example, in the embodiment of FIG.
If the pitch difference is multiplied by the number of one of the communication holes as shown in FIG. 2B, the end of the communication hole 11 having a small pitch is next to the one of the one end having a large pitch. (The reference point is the next hole 14), and from that state, the displacement is adjusted by the same operation. As shown in FIG. 10, the one end 8a side of the fixing ring 8 may be the main scale side, and the connecting piece 10 may be the sub-scale side (B ′ <A ′, B <A).

In the fastening with the connecting piece 10 described above, the rivet fastening between the connecting piece 10 and the other end 8b of the fixing ring 8 is performed before the fitting of the fixing ring 8 into the groove 9 and before the expansion and contraction after the fitting. , The hole 12,
In the case where there are a plurality of 15s, the width of the expansion displacement can be arbitrarily determined depending on the selection of the hole, and therefore it is preferable that the width be after the expansion and contraction.

FIGS. 11 and 12 show an embodiment in which both ends 8a and 8b of the fixing ring 8 are overlapped without using the connecting piece 10, and the form of the holes 11, 13 and 14 is the same as described above. . In each of the above embodiments, including this embodiment, the number of communication holes on the main scale side can be larger than the number of communication holes on the vernier side (see a chain line diagram in FIG. 9A). By doing so, the diameter deviation can be adjusted within the range of the number of communication holes on the main scale so that the calipers can be measured within the range of the main scale. At this time, if the jig hole 13 gets in the way, the jig is appropriately shifted.

FIGS. 13 (a) and 14 (a) show the case where fine adjustment is unnecessary in each of the above-described embodiments, that is, the case where the diameter change of the fixing ring 8 can be absorbed only by the compressibility of the anticorrosion core 7. In this case, the number of holes 11 and 14 is one. At this time, one of the holes 11 and 14 may be formed at the construction site in correspondence with the other. On the other hand, as shown in FIGS. 2B and 2B, one of the holes 11 or 14 is formed in a plurality in the length direction so that a change in the diameter of the fixing ring 8 can be absorbed by selecting the hole. obtain.
At this time, it is preferable that the pitches of the holes 11 and 14 are equal, but an appropriate pitch may be used.

FIGS. 15 to 18 show various aspects of the pipe end to which the anticorrosion core 7 is fixed, and FIG.
FIG. 16 shows an anti-corrosion core 7 having an abrasion-resistant layer 7a formed by fusing an ultra-high molecular weight polyethylene film at a position where the anti-corrosion core 7 is easily worn,
FIG. 17 shows that the upper edge of the anticorrosion core 7 is interposed on the lower surface of the insertion ring 4 to effectively prevent the core 7 from peeling off.
A rib 8c is provided on the fixing ring 8 over its entire length in the longitudinal direction.
Is provided to enhance the crimping state of the fixing ring 8. Each of these examples may adopt those features to each other.

In each of the above embodiments, the blind rivet 2
0, the members 8a, 8b, and 10 are fastened. However, in the embodiment shown in FIG. 1, the holes on both ends 8a and 8b of the fixing ring 8 are screw holes, and The screw may be fastened by screwing a screw through the hole 14 into the hole. If the tapping screw is used, the holes 11 and the like need not be screw holes.

Although the embodiment is of the NS type, the present invention is applied not only to the structure for fixing the anticorrosion core at the other end of the tube, but also to the standard end of the tube, not limited to the cut tube. Obviously you can get it.

[0034]

As described above, according to the present invention, the function of preventing the diameter reduction of the fixing ring is given to the fixing ring, so that the aging deterioration of the expanding force of the fixing ring is suppressed. The degree of adhesion is also maintained for many years, and it is possible to effectively prevent the anticorrosion core from falling off against expansion and contraction and bending of the joint portion, and to prevent red water for a long period of time.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of an embodiment.

FIG. 2 is a plan view of a main part of FIG. 1;

FIG. 3 is a cutaway view of a main part of FIG. 1;

FIG. 4 is a diagram showing a fastening action of the fixing ring of the embodiment.

FIG. 5 is a diagram showing a fastening action of the fixing ring of the embodiment.

FIG. 6 is an operation diagram of the blind rivet of the embodiment.

FIG. 7 is an operation diagram of the embodiment.

FIG. 8A is an operation diagram of the embodiment.

FIG. 8B is an operation diagram of the embodiment.

FIG. 8C is an operation diagram of the embodiment.

FIG. 9 is an operation diagram of another embodiment.

FIG. 10 is an operation diagram of another embodiment.

FIG. 11 is a perspective view of a main part of another embodiment.

FIG. 12A is a perspective view of a fixing ring of the embodiment.
(B) is an operation diagram of the embodiment.

FIG. 13 is a perspective view of a fixing ring according to another embodiment.

FIG. 14 is a perspective view of a fixing ring according to another embodiment.

FIG. 15 is a sectional view of another example of the pipe end anticorrosion structure.

FIG. 16 is a sectional view of another example of the pipe end anticorrosion structure.

FIG. 17 is a sectional view of another example of the pipe end anticorrosion structure.

FIG. 18 is a sectional view of another example of the pipe end anticorrosion structure.

FIG. 19 is a sectional view of a main part of a pipe joint.

FIG. 20 is an enlarged sectional view of a main part of a pipe insertion port.

[Explanation of symbols]

 1, 2 pipe 1a receiving opening 2a insertion opening 7 anticorrosion core 8 anticorrosion core fixing ring 8a, 8b fixing ring end 9 fixing ring fitting groove 10 coupling piece 11, 12, 13, 14, 15 hole 16 rivet groove ( (Recess) 20 Blind rivet P Snap ring pliers (Jig for expanding diameter)

Claims (8)

[Claims] 1. A fixing ring 8 is provided around the entire inner surface of a cylindrical portion inserted into the inner surface of a tube end of a tube end anticorrosion core 7, and the cylindrical portion is attached to the tube end by the fixing ring 8. The fixing ring 8 is fixed to the pipe end by pressing against the inner surface of the pipe end.
a and 8b are formed such that the fixing ring 8 overlaps the inner surface of the pipe end anticorrosion core 7 in a press-contact state to form communication holes 11 and 14, and the blind rivets 20 are inserted into the communication holes 11 and 14 from inside the fixing ring 8; The blind rivet 2
A structure for fixing a pipe end anticorrosion core, wherein both end portions 8a and 8b of the fixing ring 8 are fastened by 0. 2. A fixing ring 8 is provided over the entire inner surface of the cylindrical portion inserted into the inner surface of the tube end of the tube end anticorrosion core 7, and the cylindrical portion is connected to the cylindrical portion by the fixing ring 8. The fixing ring 8 is fixed to the pipe end by pressing against the inner surface of the pipe end.
The connecting ring 10 is overlapped with the fixing ring 8 on the inner surface of the pipe end anticorrosion core 7 in a press-contact state on a and 8b, and communication holes 11, 12, and 14 are provided between the connecting piece 10 and both ends of the fixing ring 8, respectively. , 15 are formed.
A blind rivet 20 is inserted into each of the fixing rings 8 from the inside of the fixing rings 8, 1, 12, and 15, and both ends of the fixing ring 8 are fastened by the blind rivets 20 through the coupling pieces 10. Fixing structure of pipe end anticorrosion core. 3. The communication device according to claim 1, wherein both ends 8a and 8b of the fixing ring 8 have communication holes 11 of the same size.
14 are formed at equal pitches in the length direction of the fixing ring 8, and the communication holes 1 at both ends 8a and 8b thereof are formed.
Pitches 1 and 14 are different, and a blind rivet 20 is inserted into corresponding communication holes 11 and 14 of both ends 8a and 8b of the fixing ring 8, and both ends 8a and 8b are fastened. Fixing structure of pipe end anticorrosion core. 4. A plurality of communication holes 11, 14 of the same size are formed at one end 8a of the fixing ring 8 and the coupling piece 10 at the same pitch in the longitudinal direction. And the communication hole 11 at the end 8a.
The pitch of the communicating hole 14 of the connecting piece 10 is different from that of the connecting piece 10. A blind rivet 20 is inserted into one end 8a and the corresponding communicating hole 11, 14 of the connecting piece 10, and the end 8a and the connecting piece 10 are fastened. A fixing structure for a pipe end anticorrosion core, which is characterized in that: 5. The fixing device according to claim 4, wherein the other end of the fixing ring and one of the connecting pieces are connected to each other.
b, a plurality of the communication holes 12, 15 for fastening are formed in the length direction of the fixing ring 8 or the coupling piece 10, and the pitch of the communication holes 12, 15 is coupled with the one end 8a. A fixing structure of a pipe end anticorrosion core, wherein the length is obtained by multiplying a pitch difference between both communication holes 11 and 14 of a piece 10 and a smaller number of the communication holes 11 and 14 in a length direction thereof. 6. The fixing ring according to claim 3, wherein
The same number of both end portions 8a, 8b, or one end portion 8a of the fixing ring 8 and the two communication holes 11, 14 of the coupling piece 10 are provided.
The number obtained by multiplying the number obtained by subtracting one from the number of communication holes having a large pitch by the pitch and the number obtained by multiplying the number of communication holes having a small pitch by the pitch are set to be the same. Fixing structure of pipe end anticorrosion core. 7. The pipe according to claim 1, wherein the pipe end anticorrosion core is provided with a concave portion for accommodating a projection from the fixing ring of the blind rivet. Fixing structure of end protection core. 8. A fixing structure for a pipe end anticorrosion core according to claim 1, wherein the fastening by the blind rivet 20 is replaced by fastening by screws.