KR20200083882A - Coated metal pipe with socket and pipe connection structure using the same - Google Patents

Abstract

The present invention relates to a coated metal pipe with a socket and a pipe connection structure using the same. The coated metal pipe, a metal pipe whose external surface is coated with a resin film, has a socket including: a first socket unit whose one end is extended to allow another pipe to be inserted; a second socket unit formed by being connected to the first socket unit and formed by extending the metal pipe to place a seal ring in an inner circumference; and a socket ring placed to wrap around a circumference on an end of the second socket unit, and having a compression bump extended in a longitudinal direction of the pipe, wherein an outer circumferential edge having the maximum external diameter of the second socket unit can be compressed on an inner circumferential surface of the compression bump, a hanging bump extended in the direction of radiation of the pipe, wherein a connection member for connecting to the other pipe inserted into the first socket unit can be hung on the hanging bump, a contact surface formed to come in full contact with a resin film on an external surface of the second socket unit, and a contact bump extended in a circumferential direction on the contact surface. The socket has the outer circumferential edge deformed to be forcibly inserted into an inner circumferential surface of the compression bump. In addition, the present invention provides a structurally stable pipe connection structure by using such a coated metal pipe.

Description

Coated metal pipe with socket and pipe connection structure using the same}

An embodiment of the present invention relates to a coated metal pipe having a socket used for pipe connection and a pipe connection structure using the same.

A socket connection method of forming a socket and a locking jaw at one end of a pipe, inserting one end of another pipe connected to each other into the socket, and connecting a pipe to each other by connecting a connecting member to the locking jaw is a very common pipe connecting method. to be. However, it is difficult to form a socket and a locking jaw for interconnection of pipes at the end of a metal pipe such as a steel pipe, which is disadvantageous in terms of manufacturability and economical efficiency in manufacturing by molding using a mold. Therefore, even though metal pipes such as steel pipes manufactured by a method such as extrusion or welding have excellent mechanical properties, they are not used as much as cast iron pipes or synthetic resin pipes in applications where the socket connection method is suitable.

In addition, metal pipes, such as steel pipes, require a coating to improve the corrosion resistance of the metals. Since the internal coating is mostly a polymer synthetic resin film that is weak to heat, a non-welded connection method is required to connect the coated metal tube. This is because the resin coating film on the connecting portion is damaged when the coated metal pipe is connected by a welding connection method. Socket connection is one of the most economical and reliable connection methods as a non-contact connection method. However, to date, there is no suitable method for forming a socket and a locking jaw required for connecting a socket to a coated metal tube.

Korean Patent Registration No. 10-1780411 discloses a prior art for solving this problem. In the prior art, a socket is formed at one end of the first sheathed steel pipe among the two pipes to be connected to each other, one end of the second sheathed steel pipe is inserted into the inside of the socket, a fitting socket is fitted to the outer periphery of the socket, and the socket and the second pipe are Between the rubber ring (sealing ring) is interposed, the second clad steel pipe is equipped with a pressure wheel that pushes the rubber packing, and the pressure ring and the socket ring are approached by a fastening bolt, so that the first tube and the second tube are bound together. , It has a configuration in which airtightness is maintained by the sealing ring.

Such a conventional technology can connect a metal pipe such as a steel pipe by a mechanical connection type. However, the joint socket is only caught by the locking jaw on the outer periphery of the socket, and the position is not fixed to the metal tube where the socket is formed, so the joint socket is placed in an inappropriate position during the pipe connection process, or the joint socket is moved by external force. Phenomena, etc. may occur, which may cause problems in the stability and reliability of the pipe connection. In addition, when connecting the pipe, after inserting one end of the pipe into the joint socket, it is necessary to bring it to the other end and assemble to the pipe, there is a problem that the pipe connection process is complicated and difficult.

Korean Patent Registration No. 10-0149745 discloses a conventional technique capable of fixing a socket ring having a locking jaw to a metal tube. Here, the socket ring plays the same role as the joint socket described above in the connection structure of the pipe. In the related art, the socket is formed on the outer circumferential surface of the socket while the outer circumferential surface of the expanded socket is pinched on the inner circumferential surface of the socket ring while the socket is formed on one end of the metal tube by expanding the one end of the metal tube while one end of the metal tube is inserted into the socket ring. It is a fixed structure. However, when such a prior art is applied to a coated metal tube, there is a problem that the coating film is peeled off or damaged. In the case of a metal tube coated with a resin film with a thickness of 1 mm or more on the outer surface, the coating film coated on the metal tube is subjected to shear stress during the expansion process, thereby causing the coating film to be very thin during the expansion process, and the expansion process After a little time has elapsed after the end, the shear stress is released and the thickness of the coating film is restored to the original thickness. However, as the socket ring is inserted in the middle of the expanded portion, a problem occurs that the coating film pushed by the shear stress is blocked by the socket ring and cannot be restored to the original thickness. The coating film in which the shear stress is not resolved has a problem in that the thickness is non-uniform and peeled or damaged from the surface of the metal tube due to potential stress.

Metal pipes, such as steel pipes, have excellent mechanical properties, but are susceptible to corrosion, so it is essential to coat the inner layer with an outer layer. When the metal tube has a completely uniform structure with no irregularities on the outer surface, it is easy to form an anticorrosive coating film on the outer surface of the metal tube. Therefore, the step of forming the uneven portion on the outer surface of the metal tube is preferably performed after forming the corrosion-resistant coating film on the outer surface. However, in the related art, when the socket and the locking jaw are formed on the coated metal tube, there is a problem that the coating film is damaged and peeled off. In the case of a resin film with a soft and thick coating, this problem is more serious.

Republic of Korea Registered Patent Publication No. 10-1780411 (October 10, 2017) Republic of Korea Registered Patent Publication No. 10-0149745 (Dec. 03, 2018)

An embodiment of the present invention is to provide a coated metal tube provided with a socket and an outer locking jaw for connecting the tube. In particular, it is intended to provide a coated metal tube in which an outer locking jaw required for connection of the tube is formed without damaging the coating film.

An embodiment of the present invention is intended to provide a more advantageous coated metal pipe and a pipe connection structure using the same when the pipe is connected to a coated metal pipe with a socket, which is easy to connect and prevents separation of pipes joined together.

According to an embodiment of the present invention, as a metal tube coated with a resin film on the outer surface; A first socket part formed by expanding one end so that another tube can be inserted; A second socket portion connected to the first socket portion and formed by expanding the metal tube so that the sealing ring is positioned on the inner periphery; It is positioned around the circumference of the end of the second socket portion, and is made of a metal material to partially or entirely have an internal coating, and the circumferential edge having a maximum outer diameter at the second socket portion can be pressed to the inner circumferential surface. It extends in the lengthwise direction of the tube, and a locking jaw, which is capable of engaging a connecting member for connection with the other tube inserted in the first socket part, is formed extending in a radial direction of the tube, and the second socket A contact surface that can be in close contact with the resin film on the outer surface is formed, and the contact surface comprises a socket ring formed with contact protrusions extending in a circumferential direction; A coated metal tube with a socket may be provided, characterized in that the outer circumferential edge is deformed on the inner circumference of the crimping jaw.

In addition, the tapered surface may be formed such that the inner diameter of the crimp is gradually enlarged toward the end.

Further, a step or irregularity may be formed on the inner circumferential surface of the crimping jaw so that the end of the second socket portion inserted into the inner circumferential surface of the crimping jaw may be caught.

According to an embodiment of the present invention, a resin film is coated on the outer surface, a first socket part having one end expanded so that a second tube can be inserted, and the first socket part so that a sealing ring is located on the inner circumferential surface. A coated metal tube formed with a second socket part connected to the tube and expanded; A second pipe having one end inserted into the first socket portion; Located on the circumference of the end of the second socket portion, a part or all of which is made of a metal material and has an internal coating, and the circumferential edge having a maximum outer diameter at the second socket portion can be compressed on the inner circumferential surface. It is extended in the longitudinal direction of the tube, and the locking jaw, which can be hung by a connecting member for fixing with the pressure wheel, into which the other tube is inserted, is formed extending in the radial direction of the tube. A socket ring on which an adhesive surface that can be in close contact with the resin film on the outer surface of the second socket portion is formed, wherein the contact surface is formed with an adhesive protrusion extending in a circumferential direction; A sealing ring interposed between the outer peripheral surface of the second pipe and the coated metal pipe to seal a gap; The second pipe is inserted, the connecting member is fixed, and the inner peripheral surface of the insertion hole into which the second pipe is inserted is tapered to form a pressing surface; Located between the sealing ring and the rolling wheel, an inclined surface corresponding to the pressing surface is formed on an outer circumferential surface, pressure can be applied to the sealing ring by a force transmitted from the pressing wheel, and a force transmitted from the pressing wheel is applied. A grip ring that can be compressed around the second tube; A connecting member connecting the socket ring and the pressure wheel to each other; It is configured to include, it can be provided with a pipe connecting device characterized in that the outer peripheral edge is formed while being deformed to fit on the inner peripheral surface of the crimp.

In addition, it has a shape of a ring, is located between the sealing ring and the grip ring, may include a washer ring for uniformly transmitting the pressure transmitted from the grip ring to the entire sealing ring.

Means for solving the problems will be more specific and clear through examples, drawings, and the like described below. In addition, in the following, various solutions other than the solutions mentioned can be further suggested.

According to an embodiment of the present invention, it is possible to provide a coated metal tube capable of socket connection. The socket connection method is a typical method of the non-weld connection method, and can be used in various applications where the welding connection method is difficult. In particular, when connecting a coated metal tube by welding, the coating film of the connection part is damaged, so the socket connection method is very useful in the coated metal tube.

According to an embodiment of the present invention, the coating film formed on the outer surface of the metal tube is not damaged at all in the process in which the socket ring with the locking jaw is fixed to the coated metal tube, and has the advantage of being well preserved in its original state.

According to an embodiment of the present invention, the inner circumferential surface of the crimp formed in the socket ring is tapered to gradually enlarge the inner diameter, so that the socket end formed at one end of the coated metal tube can be easily fitted. In addition, a step or irregularity in which the socket end is caught between the inner circumferential surfaces of the socket ring is formed, so that the inserted end of the socket cannot be easily removed in the reverse direction.

According to an embodiment of the present invention, since the coated metal pipe can be connected by a socket connection method, it is possible to provide various coated metal pipe connections that require a mechanical connection method, and in the process of forming a socket and a locking jaw on the coated metal pipe. There is an advantage that the coating film is not damaged and the original physical properties and shape can be maintained. In addition, it is easy to connect the coated metal pipe, and it is possible to provide a pipe connection structure having a high connection strength.

1 is a conceptual view showing a connection structure of a coated metal tube according to the present invention.
2 is a conceptual diagram showing a grip ring used in the connection structure of the coated metal tube according to the present invention.
3 is a conceptual view showing a second expansion pipe portion and a socket ring of a coated metal pipe according to the present invention.
4 is a conceptual view showing that the outer circumferential edge of the coated metal tube according to the present invention is forcibly coupled to the socket ring.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. For reference, in the drawings referenced to describe an embodiment of the present invention, the size of a component, the thickness of a line, and the like may be exaggerated for convenience of understanding. In addition, the terms used to describe the embodiments of the present invention are mainly defined in consideration of functions in the present invention, and thus may vary according to a user's, operator's intention, and customs. Therefore, the terms should be interpreted based on the contents throughout the present specification.

1 is a conceptual view showing a connection structure of a coated metal tube according to the present invention.

The coated metal pipe 1, which is one of the two pipes connected to each other, is coated with a resin film 10 on its outer surface, and a first socket portion 11 with one end expanded so that a second pipe can be inserted therein, The second socket portion 12 is formed to be connected to the first socket portion 11 so that the sealing ring 4 is located on the inner circumferential surface. In addition, one end of the second pipe 2 connected to the coated metal pipe 1 is inserted into the first socket portion.

A socket ring 7 made of a metal material is positioned around the end of the second socket portion 12. The socket ring 7 has a crimp 75 formed extending in the longitudinal direction of the coated metal tube, and an outer circumferential edge 15 having a maximum outer diameter in the second socket portion is inserted into the inner circumferential surface of the crimp jaw. In addition, the socket ring 7 has a locking jaw 71 formed to extend in a radial direction of the coated metal tube, and a connecting member 3 fixedly connected to the pressing wheel into which the second tube is inserted is hung on the locking jaw have. In addition, the socket ring 7 is formed with a contact surface 73 that can be in close contact with the resin film on the outer surface of the second socket portion 12, and the contact protrusion 74 that extends in the circumferential direction is formed on the contact surface 74 ) Is formed. The socket ring of a metal material also requires an internal coating. Since it is difficult to coat after bonding to the coated metal tube, it is preferable to coat all or part of the coating to the coated metal tube.

A sealing ring 4 made of an elastic material such as rubber is interposed between the outer circumferential surface of the second pipe 2 and the coated metal pipe 1 to seal the gap.

The second pipe 2 is inserted into the insertion hole 83 formed at the center of the pressing wheel 8, and the connecting member 3 is connected to the socket ring 7 and fixed to each other. In addition, the inner circumferential surface of the insertion hole into which the second pipe is inserted is formed with a tapered pressing surface 85 so that pressure can be applied to the inclined surface 63 formed on the outer circumferential surface of the adjacent grip ring 6. The connecting member 3 is fixed by connecting the socket ring 7 and the pressure wheel 8 to each other. The narrower the distance between the socket ring 7 and the pressure wheel 8 using the connecting member, which can be configured with a fastening bolt, the stronger the pressing surface 85 presses the inclined surface 63 .

A grip ring 6 having a ring shape and having an inclined surface 63 corresponding to the pressing surface 85 of the rolling wheel formed on an outer circumferential surface is positioned between the sealing ring 4 and the rolling wheel 8. The grip ring 6 may move toward the sealing ring 4 by the force transmitted from the pressing surface 85 of the pressure wheel to the inclined surface 63 or may be compressed around the second pipe.

A washer ring 5 in the form of a ring is located between the sealing ring 4 and the grip ring 6. In many cases, the grip ring is configured to be partially cut so that the inner diameter becomes small, so that the grip ring cannot apply pressure to the sealing ring in the broken portion. The washer ring is located between the grip ring and the sealing ring, and serves to uniformly transmit the pressure transmitted from the grip ring to the entire sealing ring.

2 is a conceptual diagram showing a grip ring used in the connection structure of the coated metal tube according to the present invention.

It is wider on both sides of the grip ring 6, and the side facing the sealing ring becomes the sealing surface 65. When the pressing surface of the rolling wheel pushes the inclined surface 63 formed on the outer circumferential surface of the grip ring, the grip ring moves toward the sealing ring 4 and applies pressure to the sealing ring to create a gap between the outer surface of the second pipe and the socket of the coated metal pipe. Can be sealed. However, the grip ring 6 has a cut portion in the middle, and it is difficult to press the entire sealing ring evenly because there is no sealing surface. Therefore, it is preferable to put the washer ring 5 between the sealing surface 65 and the sealing ring 4 so that the washer ring presses the sealing ring evenly.

The grip ring 6 has a cut portion in the middle, and a grip space 60 is in the cut portion. When the grip ring is pressed against the second tube by receiving the force on the inclined surface formed on the outer circumferential surface of the grip ring, the gripping space is narrowed and the inner diameter of the grip ring is narrowed as the broken parts of the grip ring come close to each other.

Spikes 69 extending in the circumferential direction are formed on the inner circumferential surface of the grip ring 6, which makes it difficult for the second pipe to escape from the grip ring when the grip ring is pressed against the second pipe to catch the second pipe. It is for sake.

The second pipe 2 may be a pipe of various materials including a metal pipe and a plastic pipe, in particular, a pipe formed of PVC (Polyvinyl Chloride) or PE (Polyethylene), or a resin such as PE or urethane coated. If the tube surface is slippery and the friction is small, it is very difficult to fix the second tube so that it does not deviate from the socket of the coated metal tube. The spike 69 of the lip ring 6 is particularly useful for a tube having such a small frictional force and a slippery surface. In addition, since the grip ring 6 has an inclined surface 63, as the second tube integrated with the grip ring tries to pass through the pressure wheel, more pressure is applied to the inclined surface and the grip ring compresses and secures the second tube. It is a structure. That is, while the grip ring functions as a wedge, the second tube cannot be detached from the rolling wheel.

The representative metal tube in the coated metal tube 1 is a steel tube, and the most common coating materials are resin films such as PE, PVC, and urethane. Materials that can be used as metal pipes include steel pipes, aluminum pipes, stainless steel pipes, and copper pipes. In addition, the coated metal pipe and the second pipe are not limited to straight-type straight pipes, and all types of molded pipes including T-type connecting pipes, fitting pipes, and curved pipes are possible.

3 is a conceptual view showing a second expansion pipe portion and a socket ring of a coated metal pipe according to the present invention.

The socket ring 7 is integral with the coated metal tube 1 and serves to fix the coated metal tube to the connecting member 3 connected to the pressure wheel 8. To this end, a locking jaw 71, through which a connecting member having a shape such as a bolt can be caught, is formed to extend in a radial direction of the coated metal tube.

If the socket ring 7 is separated from the coated metal tube, the two must be assembled at the piping site, and the process is very complicated and difficult because the socket ring must be dragged from one end of the tube to the other. Also, if the socket ring is not properly connected in the correct position, there may be a problem with the connection. Therefore, the socket ring is preferably formed integrally with the coated metal pipe and supplied to the pipe site. In order to fix the socket ring to the coated metal tube, the socket ring 7 has a crimp 75 formed extending in the longitudinal direction of the coated metal tube. The inner diameter 79 of the inner circumferential surface 76 of the crimping jaw is formed smaller than the maximum outer diameter 19 of the end of the coated metal tube. The portion having the largest outer diameter at the end of the second socket portion of the coated metal tube is the outer edge 15, and the outer diameter of the outer edge is the largest outer diameter 19 of the end of the coated metal tube.

When the second socket portion of the coated metal tube is pushed into the inside of the socket ring 7, the outer surface of the second socket portion has a tapered shape, and the second socket portion is gradually pushed in. Since the outer diameter 19 of the outer circumferential edge 15 of the second socket portion is larger than the inner diameter 79 of the crimping jaw of the socket ring, the outer circumferential edge is pushed against the crimping jaw and is dragged to the inner circumference of the crimping jaw. When there is a coating film having a slippery outer surface of the outer circumferential edge contacting the crimping jaw, it is easier to pull the outer circumferential edge into the crimping jaw. Conversely, in the direction in which the outer circumferential edge comes out of the crimp, the metal part of the tube is caught in the reverse direction without a coating film. That is, it is relatively easy to fit when entering the forced fit, and it is a very difficult structure to come out again.

As the outer circumferential edge is deformed by interference with the crimping jaw, the outer circumferential edge may be compressed with a strong force on the inner circumferential surface of the crimping jaw as it is forcibly fitted into the inner circumference of the crimping jaw. Once the outer circumferential edge that has entered the crimping chin inner circumference is to escape again, the outer circumferential edge is caught in the crimping chin inner circumference because it is the reverse of the taper of the second socket portion. That is, it is a structure in which the outer circumferential edge is difficult to escape from the crimp. In addition, irregularities or steps may be provided on the inner circumference of the crimping jaw so that the outer circumferential edge is more reliably caught on the inner circumference of the crimping jaw. The inside diameter of the crimping jaw may be processed with a larger tipper. Even if the unevenness or step formed on the inner circumference of the crimp is very small, the effect is very large. As a simple method of forming a step, the coating film on the inner circumference of the crimp can be partially removed to form a step corresponding to the coating film.

As the outer circumferential edge 15 of the second expansion tube 12 is deformed on the inner circumferential surface 76 of the crimp jaw of the socket ring 7, the socket ring can be fixed to the coated metal tube. Since the socket ring is fixed to the second expansion pipe portion, it is possible to manufacture a coated metal pipe in which both the socket and the locking jaw are integrally provided.

When the second socket portion 12 is completely inserted into the socket ring 7, the outer surface of the second socket portion comes into contact with the contact surface 73 of the socket ring. In the process of connecting the pipe, by using the connecting member 3 for subsequently fixing the socket ring 7 and the rolling wheel 8, the closer the distance between the socket ring and the rolling wheel, the closer the contact surface 73 of the socket ring is. It is in close contact with the outer surface of the socket. In this case, when the contact surface and the outer surface of the second socket portion are slippery, the second socket portion may be deformed while being pushed into the contact surface. In order to prevent such a case, a contact protrusion 74 formed to extend in a circumferential direction is formed on the contact surface. The contact protrusion prevents sliding between the contact surface and the outer surface of the second socket portion. In the normal case, since the coating film of the metal tube has a thickness of 1 mm or more, a height of 1 mm lower than the thickness of the coating film is suitable for the contact protrusion. When the adhesive protrusion completely penetrates the coating film and comes into contact with the surface of the metal tube, the coating film is destroyed, and the corrosion resistance of the coating film may be reduced.

4 is a conceptual view showing that the outer circumferential edge of the coated metal tube according to the present invention is forcibly coupled to the socket ring.

In Fig. 4A, the inner diameter 79 of the crimp is smaller than the outer diameter 19 of the outer circumferential edge. However, in FIG. 4(b), the outer circumferential edge 15 is deformed by interference fit, and the inner diameter 79 of the crimping jaw and the outer circumferential edge of the deformed fitted outer edge coincide with each other. Since the outer circumferential edge is exposed without a coating coating, it is preferable that the metal portion of the outer circumferential edge directly contacts the inner circumferential surface of the crimp. In order to help the outer circumferential edge to enter the inner circumferential surface of the crimping jaw, a tapered surface 77 in which the inner diameter of the crimping jaw gradually enlarges toward the end of the crimping jaw may be formed.

When the second expansion tube part is completely inserted into the crimp, the outer surface of the second expansion tube part comes into contact with the contact surface of the socket ring. Even if the outer surface of the second expansion pipe part does not completely adhere to the contact surface of the socket ring in the process of fixing the socket ring, if the distance between the socket ring and the pressure wheel is narrowed using a connecting member in the process of connecting the coated metal tube, The second expansion pipe portion is in close contact with the contact surface by the gripping grip. In addition, the second expansion portion in close contact with the contact surface is prevented from sliding on the contact surface by the contact protrusion formed on the contact surface.

Summarizing the method of manufacturing a coated metal tube equipped with a socket; Corrosion-resistant resin is coated on the outer surface of a metal pipe such as a steel pipe, the coated metal pipe is expanded to form a socket, and the outer circumferential edge 15 of the end of the socket is inserted into the inner circumferential surface of the socket ring 7 by interference fit, and the locking jaw The formed socket ring is fixed to the outer peripheral surface of the socket end. The advantages of this fabrication method are; In the process of fitting and fixing the socket ring to the coated metal tube, the outer peripheral edge, which is the end of the metal tube without the coating film, is used, so that the coating film formed on the metal tube has no deformation or damage.

Although the present invention has been described above, the present invention is not limited by the disclosed embodiments and the accompanying drawings, and can be variously modified by those skilled in the art without departing from the technical spirit of the present invention. In addition, the technical idea described in the embodiments of the present invention may be implemented independently of each other, or two or more may be performed in combination with each other.

1: coated metal tube 2: second tube
3: Connecting member 4: Sealing ring
5: washer 6: grip ring
7: Socket ring 8: Rolling ring
10: resin film 11: first socket portion
12: second socket portion 15 outer edge
19: maximum outer diameter of the second socket
63 Inclined surface 65 Sealed surface
71 Hanging jaw 73 Close contact surface
75 Crimping jaw 76 Crimping jaw
77 Taper side 79 Crimping inside diameter

Claims (5)

As a metal tube with an outer surface coated with a resin film;
A first socket part formed by expanding one end so that the second tube can be inserted;
A second socket portion formed by being connected to the first socket portion and expanding the metal tube so that a sealing ring is positioned on an inner circumference;
Located around the circumference of the end of the second socket portion, the crimping jaw that can be compressed on the inner circumferential edge of the outer circumferential edge having the largest outer diameter in the second socket portion extends in the longitudinal direction of the tube, and the first socket portion A locking jaw, which can engage a connecting member for fixing the connection with the second pipe inserted into the tube, is formed to extend in a radial direction of the tube, and a contact surface that can be in close contact with the outer surface of the second socket is formed. , The contact surface is configured to include a socket ring formed with a contact protrusion formed to extend in the circumferential direction;
A coated metal tube with a socket, characterized in that the outer circumferential edge is deformed on the inner circumferential surface of the crimping jaw to form a forced fit. The method according to claim 1,
A coated metal tube with a socket, characterized in that a tapered surface is formed in which the inner diameter of the crimp is gradually enlarged toward the end of the crimp. The method according to claim 1,
A coated metal tube with a socket characterized in that a step or irregularity is formed on the inner circumferential surface of the crimping jaw so that the end of the second socket portion inserted into the inner circumferential surface of the crimping jaw may be caught. The outer surface is coated with a resin film, and the first socket portion is formed with one end expanded so that the second pipe can be inserted, and the second socket connected to the first socket portion and expanded so that the sealing ring is located on the inner periphery. A coated metal tube formed with an addition;
A second pipe having one end inserted into the first socket portion;
Located in the circumference of the end of the second socket portion, the crimping jaw, which can be compressed on the inner circumferential edge of the outer circumferential edge having the largest outer diameter in the second socket portion, extends in the longitudinal direction of the tube and secures the connection with the rim. A locking jaw, which can be connected to the connecting member, is formed to extend in the radial direction of the tube, and a contact surface to be in close contact with the outer surface of the second socket is formed, and the contact surface is formed to extend in the circumferential direction. A socket ring in which contact protrusions are formed;
A sealing ring interposed between the outer peripheral surface of the second pipe and the coated metal pipe to seal a gap;
And the second pipe is inserted into the insertion hole formed in the center, the connecting member is fixed to the connection, the pressure wheel is formed on the inner circumference of the insertion hole;
Located between the sealing ring and the rolling wheel, an inclined surface corresponding to the pressing surface is formed on the outer circumferential surface, and pressure can be applied toward the sealing ring by the force transmitted from the pressing wheel, and the force transmitted from the pressing wheel is applied. A grip ring that can be compressed around the second tube;
It comprises a connecting member for connecting and fixing the socket ring and the pressure wheel to each other;
A pipe connection structure characterized in that the outer circumferential edge is deformed on the inner circumferential surface of the crimping jaw to form a forced fit. The method according to claim 4,
It has a shape of a ring, located between the sealing ring and the grip ring, the pipe connection structure characterized in that it comprises a washer ring for uniformly transmitting the pressure transmitted from the grip ring to the entire sealing ring.

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