JP5327858B2 - Pipe joint, pipe connection structure and pipe connection method - Google Patents

Description

  The present invention relates to a pipe joint used for connecting various pipes such as a water supply pipe and a hot water pipe, and a pipe connection structure and a pipe connection method using the pipe joint.

  In recent years, composite pipes provided with an inner layer and an outer layer made of a synthetic resin (for example, cross-linked polyethylene) with a metal (for example, aluminum) intermediate layer interposed therebetween are widely used as various pipes such as a water supply pipe, a hot water supply pipe, and a heating pipe. .

  And as a pipe joint for connecting such a composite pipe, a composite pipe is connected between the cylindrical insertion part (connection part) provided in the one end side of the joint main body, and the compression ring arrange | positioned on this outer side. There is a so-called caulking type joint in which a composite pipe is caulked into an insertion portion by inserting and compressing and deforming a compression ring (see, for example, Patent Document 1).

JP 2005-325904 A JP 2007-333127 A

  However, in the connection work of the composite pipe using the above-described pipe joint, when the pipe to be connected is inserted and connected between the compression ring and the insertion portion, the pipe to be connected is covered with the metal compression ring. It is not possible to visually check whether or not it is inserted to a predetermined position, and there is a possibility that a connection failure may occur. In addition, a dedicated jig is used when compressing and deforming the compression ring, and it is not possible to substitute a widely used tool, and in addition to the cost and labor required for jig preparation, The connection work using the dedicated jig is unique, and the difference in the skill level may appear as the quality of the connection state of the composite pipe.

  Further, if a so-called mechanical pipe joint shown in Patent Document 2 is used, a composite pipe that is inserted through the cap nut is caulked with the fastening of the cap nut to the joint main body and connected to the joint main body. This jig is unnecessary. However, since the cap nut is transparent, it is possible to visually check the split ring inserted into the cap nut from the outside, but the insertion position of the connected pipe inserted into the split ring made of metal is external. It is still impossible to make a visual check from the above, and connection failure may occur.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to achieve a reduction in cost and to reliably avoid poor connection, and a pipe connection structure and pipe connection using the same. It is to provide a method.

In order to achieve the above object, a pipe joint according to the present invention includes a joint body having a substantially cylindrical insertion part inserted into a connected pipe on one end side,
A split ring arranged outside the insertion portion in a state in which the connected pipe can be inserted between the insertion portion and configured to be able to reduce the diameter;
A holding ring that covers the split ring and reduces the diameter of the split ring;
Wherein it is screwed to the joint body, engaging said retainer ring when you screwed against the fitting body, and a cap nut presser cover the the split ring by sliding the ring,
The split ring has a plurality of notches in the circumferential direction at the portion that contacts the joint body ,
Further, the object to be connected tube inserted into the split in the ring so that it can be visible from the outside of the cap nut through the notch, the bag nut have a light transmitting property,
Further, the press ring slides from a position not covering the notch to a position covering a part of the notch as the cap nut is screwed relative to the joint body .

  The pipe joint is externally fitted to the insertion part, pressed by the connected pipe inserted between the insertion part and the split ring, and comes into contact with the inner wall of the split ring to reduce the split ring. A fixed ring may be provided that moves from a restriction position that restricts the diameter to an allowable position that does not contact the inner wall of the split ring and allows the diameter of the split ring to be reduced (Claim 2).

  In the pipe joint, the joint body may be made of metal, and the fixing ring may be made of resin.

  On the other hand, in order to achieve the above object, a pipe connection structure according to the present invention is a pipe connection structure for connecting the connected pipe to the pipe joint according to any one of claims 1 to 3, wherein The tube is a tube provided with a layer made of synthetic resin with a metal intermediate layer interposed therebetween.

On the other hand, in order to achieve the above object, the pipe connecting method according to the present invention includes inserting the connected pipe into a cap nut screwed in a state in which a margin for screwing is left with respect to the joint body. A substantially cylindrical insertion portion provided on one end side of the main body is inserted into the connected pipe, and a split ring capable of reducing the diameter disposed outside the insertion portion and the split ring is covered with the split ring. A presser ring to reduce the diameter is fitted to the connected pipe,
The connection pipe inserted into the cap nut has advanced to a predetermined position, and the light transmission is achieved through a plurality of notches provided in the circumferential direction at a portion that contacts the joint body in the split ring . Check visually from the outside of the cap nut,
By screwing the cap nut with respect to the joint body, the presser ring engaged with the capnut is slid to cover the split ring, the split ring is reduced in diameter , and the presser ring is A part of the notch is covered (Claim 5).

Further, the pipe connecting method of the present invention is an abbreviation provided on one end side of the joint body by inserting the pipe to be connected into a cap nut screwed in a state in which a margin for screwing is left with respect to the joint body. A cylindrical insertion portion is inserted into the pipe to be connected, and a split ring capable of reducing the diameter disposed outside the insertion portion and a pressing ring for covering the split ring to reduce the diameter of the split ring are provided. The fixing ring that is externally fitted to the insertion portion is pressed against the inner wall of the split ring by pressing the fixing ring that is externally fitted to the insertion portion with the connected pipe inserted into the cap nut. Move from a restriction position that contacts and restricts the diameter of the split ring to an allowable position that does not contact the inner wall of the split ring and allows the diameter of the split ring to
The fact that the fixing ring has moved to the permissible position is visually confirmed from the outside of the cap nut having light transmittance through a plurality of notches provided in the circumferential direction at the portion of the split ring that contacts the joint body. ,
By screwing the cap nut with respect to the joint body, the presser ring engaged with the capnut is slid to cover the split ring, the split ring is reduced in diameter , and the presser ring is A part of the notch may be covered (Claim 6).

Further, in the pipe connecting method, when the holding ring is in a state of covering a part of the notch, the female screw portion of the cap nut exceeds the male screw portion of the joint body, and the cap nut is idle. You may make it be in the state to do (Claim 7).

  In the inventions according to claims 1 to 7, it is possible to obtain a pipe joint that can achieve cost reduction and can reliably avoid poor connection, and a pipe connection structure and a pipe connection method using the pipe joint.

  That is, in the inventions according to claims 1 and 5, the pipe to be connected can be connected only by operating the cap nut, and a dedicated jig or the like is not required, so that the cost can be reduced. In addition, since the insertion position of the pipe to be connected can be confirmed from the outside (outside the cap nut), it is possible to reliably avoid poor connection.

  In the inventions according to claims 2 and 6, the fixing ring can surely prevent the split ring from being reduced in diameter before the connected pipe is connected and the connected pipe cannot be inserted.

  Further, in the invention according to claim 3, for example, even when the metal part is exposed on the tip surface of the connected pipe, the metal part and the metal joint body are insulated by the resin fixing ring. The effect that electric corrosion does not occur is obtained.

  And in the invention which concerns on Claim 4, since the to-be-connected pipe has a metal intermediate layer, if the to-be-connected pipe is caulked by the reduced diameter of the split ring, the caulked state is maintained, The connection state is maintained well.

  In the invention according to claim 7, since the cap nut is idled after the connection of the pipe to be connected, an unnecessarily large load is not applied to the cap nut or the pipe to be connected, and a good connection is reproducible. Can be realized well.

It is a longitudinal section showing roughly composition of a pipe joint and pipe connection structure concerning one embodiment of the present invention. It is a disassembled perspective view which shows the structure of the said pipe joint roughly. (A) And (B) is the longitudinal cross-sectional view and bottom view which show roughly the structure of the split ring in the said pipe joint. It is a longitudinal cross-sectional view which shows schematically the structure of the said pipe joint before construction. It is a longitudinal cross-sectional view which shows schematically the structure of the said pipe joint immediately after inserting a to-be-connected pipe. It is a longitudinal cross-sectional view which shows roughly the structure of the said pipe joint in the state which inserted the to-be-connected pipe completely. It is a longitudinal cross-sectional view which shows schematically the structure of the said pipe joint and pipe connection structure after the completion of a connection. It is a longitudinal cross-sectional view which shows schematically the structure of the principal part of the said pipe connection structure in connection operation.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  The pipe joint according to the present embodiment is used, for example, for connecting the connected pipe 1 to a header (not shown) (see FIG. 1).

  First, the configuration of the connected pipe 1 will be described.

  As shown in FIG. 5, the pipe 1 to be connected is a three-layer pipe having a metal intermediate layer 1a, and an inner layer 1b and an outer layer 1c made of synthetic resin and sandwiching the intermediate layer 1a. At this time, a heat insulating material (not shown) is wound.

  Here, as the metal forming the intermediate layer 1a, for example, a light metal such as aluminum or stainless steel is adopted, and in particular, corrosion resistance, heat resistance, workability, shape retention, organic solvent and oxygen penetration prevention, anti-ant Aluminum is preferred from the standpoints of properties and economics.

  For the synthetic resin forming the inner layer 1b and the outer layer 1c, for example, cross-linked polyethylene, polypropylene, vinyl chloride, polybutene, etc. are employed, and in particular from the viewpoint of heat resistance, chlorine resistance, environmental stress crack resistance, etc. Oxide crosslinked, silane crosslinked, or radiation crosslinked crosslinked polyethylene is preferred.

  Next, the configuration of the pipe joint will be described.

  The pipe joint is provided with a metal-made substantially cylindrical joint body 2, and as shown in FIGS. 1 and 2, the joint body 2 has a large outer peripheral surface and a hollow shape (hexagonal nut shape in the illustrated example). A diameter portion 3 is provided, and cylindrical portions 4 and 5 are continuously provided on both sides of the large diameter portion 3.

  A male threaded portion 6 is formed on the outer peripheral wall of one of the cylindrical portions 4, and protrudes outward from the tip of the cylindrical portion 4 on the inner side of the cylindrical portion 4 to be connected when the connected pipe 1 is connected. A substantially cylindrical insertion portion 7 to be inserted into the tube 1 is provided continuously. Further, on the outer peripheral side of the proximal end portion of the insertion portion 7 on the distal end surface of the tubular portion 4, an annular groove 8 that surrounds the proximal end portion and is annularly recessed is provided.

  On the outer peripheral wall of the other tubular portion 5, for example, a male screw portion 9 that is screwed into a female screw portion (not shown) of the header is formed.

  A split ring 10 that can be reduced in diameter and increased in diameter is disposed (attached) on the outside of the insertion portion 7 in a state in which the tube 1 to be connected can be inserted between the insertion portion 7 and the insertion portion 7 (FIG. 1 to FIG. 1). 3). The split ring 10 is made of a colored (for example, black or white) synthetic resin such as a POM (polyacetal) resin, for example, and has a substantially C-shaped main body 11 in a cross-sectional view.

  Two protrusions 12 and 12 (see FIG. 1 and FIG. 3A) separated in the ring axis direction are formed on the inner peripheral wall of the main body 11, and the inner diameter from one end side to the other end side of the main body portion 11. Is substantially uniform except for the portions where the protrusions 12, 12 are provided. On the other hand, the outer peripheral surface of the main body 11 is a tapered surface whose outer diameter increases from one end side toward the other end side.

  Further, as shown in FIGS. 2, 3A and 3B, a plurality of (a total of eight in this example) are provided on the other end side of the main body portion 11 at intervals in the circumferential direction of the main body portion 11. Legs 13 are provided continuously.

  And the fixing ring 14 which consists of colored (for example, green) synthetic resin is accommodated inside the main-body part 11 of the split ring 10 as shown in FIG.1 and FIG.2. The outer diameter of the fixing ring 14 is slightly larger than the inner diameter of the main body 11 of the split ring 10 in the natural state where no external force is applied (the inner diameter of the portion other than the two projecting portions 12 and 12). The size is such that the portion 7 can be inserted.

  On the other hand, as shown in FIG. 1, a cap nut 15 is connected to the joint body 2. The cap nut 15 is made of a light-transmitting (transparent or translucent) synthetic resin such as polycarbonate, and has an outer peripheral surface of a polygonal shape (in this example, a hexagonal shape) as shown in FIG. . A female screw portion 16 is formed on the inner peripheral wall of the cap nut 15, and an inward flange 17 is provided on one end side.

  And the press ring 18 which can be covered on the split ring 10 is arrange | positioned in the cap nut 15 (refer FIG. 1, FIG. 2). The pressing ring 18 is made of metal, and the outer diameter from one end side to the other end is substantially uniform. On the other hand, the inner peripheral surface of the pressing ring 18 is a tapered surface whose outer diameter increases from one end side to the other end side.

  Next, a procedure for assembling the pipe joint will be described.

  First, packing (an example of a seal part) 20 is mounted in two seal grooves 19 provided on the outer peripheral wall of the insertion part 7 of the joint body 2 (see FIGS. 1, 2, and 4). Further, the fixing ring 14 is inserted (internally fitted) into the split ring 10, and the fixing ring 14 is positioned between, for example, the two protrusions 12 and 12 (see FIGS. 1 and 4). At this time, the fixing ring 14 in the split ring 10 is slightly reduced in diameter by the elastic force of the split ring 10.

  Then, the split ring 10 in a state where the fixing ring 14 is inserted is externally fitted to the insertion portion 7, and the leg portion 13 of the split ring 10 is brought into contact with the tip surface of one cylindrical portion 4 (FIGS. 1 and 4). reference).

  Thereafter, the female thread portion 16 of the cap nut 15 is screwed onto the male thread portion 6 of the joint body 2 while leaving a margin for screwing. At this time, the holding ring 18 is disposed in the cap nut 15 (FIGS. 1 and 4). reference). The cap nut 15 is connected (temporarily fixed) to the joint body 2 by the above screwing, but the screwing of the female screw portion 16 with respect to the male screw portion 6 stops to some extent, and the cap nut 15 rotates further. There is nothing. This is because the holding ring 18 that engages with the inward flange 17 of the cap nut 15 having the female screw portion 16 slides in a direction covering (fitting outside) the split ring 10 as the female screw portion 16 is screwed. However, the holding ring 18 that has moved until it is in close contact with the outer surface of the split ring 10 is prevented from further movement by the split ring 10, which cannot be reduced in diameter by the fixing ring 14. . Therefore, the fixing ring 14 can reliably prevent the split ring 10 from being reduced in diameter before the connected pipe 1 is connected to prevent the connecting pipe 1 from being inserted.

  Thus, the assembly of the pipe joint is completed, and the pipe joint in the state shown in FIG. 4 is obtained.

  Next, the connection method (connection method of a pipe connection structure) of a pipe joint and the to-be-connected pipe 1 is demonstrated.

  (1) First, as shown in FIG. 5, the connected pipe 1 is inserted from one end side of the cap nut 15 of the pipe joint toward the inside thereof, and this insertion is continued until the connected pipe 1 stops.

  That is, when the connected pipe 1 is inserted into the cap nut 15, first, the insertion portion 7 provided on one end side of the joint body 2 is inserted into the connected pipe 1, and the split ring 10, the holding ring 18, Is externally fitted to the connected pipe 1, and eventually the tip of the connected pipe 1 comes into contact with the fixing ring 14 in the split ring 10 (see FIG. 5).

  When the connected pipe 1 is further inserted, the fixing ring 14 is pressed by the connected pipe 1, and the fixing ring 14 finally enters the annular groove 8 as shown in FIG. Then, the connected pipe 1 stops. That is, the fixed ring 14 is brought into contact with the inner wall of the main body portion 11 of the split ring 10 by the connected pipe 1 inserted into the cap nut 15 to limit the diameter of the split ring 10 (see FIGS. 4 and 4). 5) to a permissible position (in this example, the annular groove 8, see FIG. 6) that does not contact the inner wall of the split ring 10 and allows the diameter of the split ring to be reduced.

  (2) It is visually confirmed from the outside of the pipe joint that the fixing ring 14 has entered the annular groove 8 (see FIG. 6).

  That is, the cap nut 15 is light transmissive, and there is a gap (an example of a notch) between the plurality of leg portions 13 of the split ring 10, and a metal that does not have light transmissive properties. Since the pressing ring 18 is in a position that does not cover the gap between the leg portions 13, the fixing ring 14 that advances in the split ring 10 toward the annular groove 8 when viewed from the outside of the cap nut 15 through the gap between the leg portions 13. And the state of the connected pipe 1 can be confirmed. Therefore, the cap nut 15 should just have the light transmittance more than the grade which the said visual observation is possible.

  The fixing ring 14 is naturally withdrawn from the split ring 10 before entering the annular groove 8, and the split ring 10 is in a state where the diameter can be reduced with the withdrawal. .

  (3) The cap nut 15 is further screwed until the female screw portion 16 of the cap nut 15 exceeds the male screw portion 6 of the joint body 2 (see FIG. 7).

  That is, when the cap nut 15 in a state where the female screw portion 16 is screwed to the male screw portion 6 of the joint body 2 (temporarily fixed) is further screwed (finally tightened), the cap nut 15 faces inward. The holding ring 18 with which the flange 17 is engaged slides in a direction covering the split ring 10. Since the portions of the split ring 10 and the pressing ring 18 that are in contact with each other are formed in a tapered surface shape, the split ring 10 is reduced in diameter as the pressing ring 18 slides over the split ring 10.

  At the same time, as shown in FIG. 8, the force acting in the direction of reducing the diameter of the split ring 10 is transmitted to the connected pipe 1 inserted through the split ring 10, and in the connected pipe 1, outside the two packings 20, 20. The located part strongly contacts each packing 20.

  Further, as shown in FIG. 8, annular grooves 21 and 21 are provided on the outer peripheral wall of the insertion portion 7 at positions facing the protrusions 12 and 12 of the split ring 10 (see also FIG. 1). Due to the force acting in the direction in which the diameter of the pipe 10 is reduced, the two portions of the connected pipe 1 that are separated from each other in the pipe axis direction pressed by the protrusions 12 and 12 of the split ring 10 are reduced in diameter, and the two annular grooves 21 and 21 are reduced. Will be accepted and caulked. In the insertion portion 7, the two annular groove portions 21 and 21 are positioned so as to sandwich the seal grooves 19 and 19 in which the packings 20 are mounted, and accordingly, the two portions to be caulked as described above are The connecting pipe 1 is formed at a position sandwiching a portion where the packings 20, 20 abut.

  On the other hand, when the cap nut 15 is further screwed after the diameter reduction of the split ring 10, the female screw portion 16 of the cap nut 15 exceeds the male screw portion 6 of the joint body 2, and as shown in FIG. The female screw avoiding portion 22 provided on the outer peripheral wall is located inside the female screw portion 16, and the male screw avoiding portion 23 provided on the inner peripheral wall of the cap nut 15 is located outside the male screw portion 6. Since the outer diameter of the female screw avoiding portion 22 is smaller than the inner diameter of the female screw portion 16, and the inner diameter of the male screw avoiding portion 23 is larger than the outer diameter of the male screw portion 6, the male screw portion 6 and the female screw portion 16 are free. The cap nut 15 is idle.

  Thus, the connection between the pipe joint and the connected pipe 1 is completed.

  In the present embodiment, the connected pipe 1 inserted into the pipe joint is connected only by the operation of the cap nut 15, so that a dedicated jig or the like is not required, and the cost can be reduced. Since the insertion position of the tube 1 can be confirmed from the outside (outside of the cap nut 15), it is possible to reliably avoid a connection failure.

  In addition, since the two parts in the position where the packings 20 and 20 are in close contact with each other are crimped in the connected pipe 1, even if the waterproofing power is reduced due to the compression set of the packings 20 and 20. The decrease can be compensated by two caulking parts.

  Furthermore, since the connected pipe 1 has the metal intermediate layer 1a, after the two parts are caulked by the operation of the cap nut 15, even if the cap nut 15 comes off or breaks, The crimped state is maintained and the connection state is maintained well.

  In addition, since the cap nut 15 is configured to idle after a predetermined amount of the connected pipe 1 is caulked, an unnecessarily large load is not applied to the cap nut 15 or the caulked portion of the connected tube 1 and is good. Connection can be realized with good reproducibility.

  In addition, the fixing ring 14 prevents the cap nut 15 from rotating and the split ring 10 from being reduced in diameter before connecting the pipe 1 to be connected. After insertion of the pipe 1 to be connected, the annular groove 8 is inserted. The metal synthetic layer 1a exposed from the distal end surface of the connected pipe 1 and the joint body 2 are insulated by the entering synthetic resin fixing ring 14 to prevent electrolytic corrosion.

  In addition, the fixing ring 14 prevents the packing 20 mounted in each seal groove 19 from being twisted or detached from the seal groove 19 due to contact with the connected pipe 1 inserted into the cap nut 15. This is because the connected pipe 1 inserted into the cap nut 15 abuts against a fixing ring 14 fitted in advance to the insertion portion 7 and moves the fixing ring 14 toward the annular groove 8. (Refer to FIGS. 5 and 6), at this time, the fixing ring 14 that goes ahead of the connected pipe 1 is surely crushed without twisting the packing 20 or detaching it from the seal groove 19 (for example, the cross section is This is because the packing 20 is deformed so as to have a substantially elliptical shape), and the connected pipe 1 follows the fixing ring 14 without any interval. Therefore, the inner portion 14 a (see FIG. 5) at the tip of the fixing ring 14 is chamfered so that the packing 20 can be reliably crushed, and the connected pipe 1 is placed in the cap nut 15. At the time of insertion, the fixing ring 14 is above the packing 20 on the upper side (upstream side in the insertion direction of the connected pipe 1) of the two packings 20 (upstream side in the insertion direction of the connected pipe 1). It is necessary to be positioned or to surround the upper packing 20.

  In the present embodiment, components such as the material and shape of each member can be changed as appropriate.

  For example, the connected pipe 1 is not limited to a three-layer pipe. That is, only a three-layer pipe is cited as an example of a composite pipe having a multilayer structure, and the connected pipe 1 may be a composite pipe having two layers or four or more layers, and may be a single-layer pipe. Also good.

  In the present embodiment, for example, a male screw portion 9 is provided on the other end side of the joint body 2 in order to connect to the header. However, instead of the male screw portion 9, a female screw portion, a cap nut, or the like is provided. In addition, the pipe joint may have a structure provided on the one cylindrical part 4 side from the large diameter part 3 of the joint main body 2 on the other cylindrical part 5 side. The cylindrical portion 5 side may be bifurcated into two or more branches, and the structure of one cylindrical portion 4 side may be provided for each of them. That is, the other end side of the joint body 2 can be appropriately configured according to the connection target (for example, a water heater, a water stopcock, etc.) of the connected pipe 1.

  Either one or both of the two projecting portions 12 and 12 may be provided not on the inner peripheral wall of the split ring 10 but on the outer peripheral wall of the insertion portion 7. In this case, either one of the two annular groove portions 21 and 21 is provided. One or both may be provided not on the outer peripheral wall of the insertion portion 7 but on the inner peripheral wall of the split ring 10. In addition, the annular groove part 21 provided in the inner peripheral wall of the split ring 10 receives the part which was pressed by the protrusion part 12 in the to-be-connected pipe 1, and was expanded in diameter.

  In the present embodiment, when the state of the fixing ring 14 and the connected pipe 1 is visually confirmed from the outside of the cap nut 15 in the step (2), the outer surface of the connected pipe 1 is white and the outer surface of the fixing ring 14 is Is green, and the outer surface of the split ring 10 is black. Therefore, it is easy to distinguish these members visually. The connected pipe 1, the fixed ring 14, and the split ring 10 can be appropriately changed in color (hue, saturation, brightness), etc. so as to be easily distinguished, for example, a difference in light transmittance. May be provided for easy discrimination. When the split ring 10 has sufficient light transmissivity, the gaps between the plurality of leg portions 13 are not necessary, so that the leg portions 13 can be omitted.

  In the split ring 10, for example, the inner diameter of the portion where the plurality of leg portions 13 are provided may be larger than the inner diameter of the main body portion 11, and the inside of the plurality of leg portions 13 may be set as the allowable position in the step (1). In this case, the annular groove 8 may not be provided.

  Further, the fixing ring 14 may not be moved from the restriction position to the allowable position in the step (1), but may be at the allowable position from the beginning. In this case, in the above step (2), it is visually confirmed that the connected pipe 1 has been inserted to a predetermined position (a position where it comes into contact with the fixing ring 14).

1 Connected pipe 2 Joint body 7 Insertion part 10 Split ring 15 Cap nut 18 Holding ring

Claims (7)

A joint body having a substantially cylindrical insertion portion inserted into the connected pipe on one end side;
A split ring arranged outside the insertion portion in a state in which the connected pipe can be inserted between the insertion portion and configured to be able to reduce the diameter;
A holding ring that covers the split ring and reduces the diameter of the split ring;
Wherein it is screwed to the joint body, engaging said retainer ring when you screwed against the fitting body, and a cap nut presser cover the the split ring by sliding the ring,
The split ring has a plurality of notches in the circumferential direction at the portion that contacts the joint body ,
Further, the object to be connected tube inserted into the split in the ring so that it can be visible from the outside of the cap nut through the notch, the bag nut have a light transmitting property,
Furthermore, the said press ring is a pipe joint which slides from the position which does not cover the said notch part to the position which covers a part of this notch part with the screwing of the cap nut with respect to the said joint main body .   A restriction that is externally fitted to the insertion portion and pressed by the connected pipe inserted between the insertion portion and the split ring so as to contact the inner wall of the split ring and limit the diameter of the split ring. The pipe joint according to claim 1, further comprising a fixing ring that moves from a position to an allowable position that does not contact the inner wall of the split ring and allows the diameter of the split ring to be reduced.   The pipe joint according to claim 2, wherein the joint body is made of metal, and the fixing ring is made of resin.   A pipe connection structure for connecting the pipe to be connected to the pipe joint according to any one of claims 1 to 3, wherein the pipe to be connected is provided with a synthetic resin layer sandwiching a metal intermediate layer. A pipe connection structure that is an open pipe. By inserting the connected pipe into a cap nut screwed in a state where a margin for screwing is left with respect to the joint body, a substantially cylindrical insertion portion provided on one end side of the joint body is inserted into the connected pipe. And a fitting ring arranged on the outside of the insertion portion and capable of reducing the diameter and a pressing ring that covers the split ring and reduces the diameter of the split ring is externally fitted to the connected pipe,
The connection pipe inserted into the cap nut has advanced to a predetermined position, and the light transmission is achieved through a plurality of notches provided in the circumferential direction at a portion that contacts the joint body in the split ring . Check visually from the outside of the cap nut,
By screwing the cap nut with respect to the joint body, the presser ring engaged with the capnut is slid to cover the split ring, the split ring is reduced in diameter , and the presser ring is A pipe connection method that covers a part of the notch . By inserting the connected pipe into a cap nut screwed in a state where a margin for screwing is left with respect to the joint body, a substantially cylindrical insertion portion provided on one end side of the joint body is inserted into the connected pipe. A split ring that can be reduced in diameter and disposed on the outer side of the insertion portion, and a press ring that covers the split ring and reduces the diameter of the split ring is externally fitted to the connected pipe, and The connecting pipe inserted into the cap nut presses the fixing ring that is externally fitted to the insertion portion, and the fixing ring is brought into contact with the inner wall of the split ring to limit the diameter of the split ring. From the limit position to move to an allowable position that does not contact the inner wall of the split ring and allows the diameter of the split ring to be reduced
The fact that the fixing ring has moved to the permissible position is visually confirmed from the outside of the cap nut having light transmissivity through a plurality of notches provided in the circumferential direction at the portion of the split ring that contacts the joint body. ,
By screwing the cap nut with respect to the joint body, the presser ring engaged with the capnut is slid to cover the split ring, the split ring is reduced in diameter , and the presser ring is A pipe connection method that covers a part of the notch . When the holding ring is in a state of covering a part of the cutout portion, the female screw portion of the cap nut exceeds the male screw portion of the joint body, and the cap nut is idle. 7. The pipe connection method according to 5 or 6.

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