Pipe fittings

Abstract

To provide a pipe joint that is an outside diameter seal type pipe joint, and can realize both appearance performance and prevention of damage to pipes at a high level.SOLUTION: A pipe joint comprises: a joint body; a first cap 21 and a second cap 22 fitted to the joint body, defining an insertion space for pipes (a resin pipe and an adapter) in cooperation with the pipe joint, in which insertion ports 48 to be used to insert the pipes into the insertion space are formed, and made of synthetic resin; a retaining member arranged in the insertion space, and for restraining the pipes inserted into the insertion space from slipping out; and a first seal ring and a second seal ring arranged in the insertion space, and for securing watertightness by being in contact with an outer peripheral surface of the resin pipe inserted into the insertion space. Gate concave parts 44 are formed in outer peripheral surfaces near the insertion ports 48 in the caps 21 and 22. Gate marks 46 of the caps 21 and 22 manufactured by injection molding are formed in the gate concave parts 44.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a pipe joint for connecting between ends of pipes in a pipe system for, for example, water supply or hot water supply, and a pipe joint for connecting an end of a pipe and a faucet fixture.

Background Art

[0002] In the pipe joint disclosed in Patent Document 1, a synthetic resin cap is attached to the pipe joint body. The synthetic resin cap is generally manufactured by injection molding. Since the cap is also an exterior part, the position of the gate is set on the inner peripheral surface of the pipe insertion port in the cap so that even if excessive gate marks occur, the appearance will not deteriorate or the operator will not be affected.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when excessive gate marks occur at the insertion port of the cap, there is a problem that when inserting the pipe into the pipe joint, the outer peripheral surface of the pipe and the gate marks rub strongly against each other, and the outer peripheral surface of the pipe is easily damaged. In particular, the pipe joint of Patent Document 1 is of an outer diameter seal type, that is, a type in which a seal member contacts the outer peripheral surface of the pipe to achieve watertightness, and the damage to the outer peripheral surface of the pipe has been a factor in reducing the watertightness of the pipe joint. An object of the present invention is to provide a pipe joint capable of achieving both high-dimensional appearance performance and prevention of pipe damage in an outer diameter seal type pipe joint.

Means for Solving the Problems

[0005] To achieve the above objective, the pipe joint of the invention according to claim 1 comprises a joint body, a synthetic resin cap attached to the joint body which defines a pipe insertion space with the joint body and has an insertion opening for inserting the pipe into the insertion space, a retaining member disposed in the insertion space to prevent the pipe inserted into the insertion space from coming out, and a sealing member disposed in the insertion space which contacts the outer surface of the pipe inserted into the insertion space to ensure watertightness, wherein a gate recess is formed on the outer surface of the cap near the insertion opening, and a gate mark of the cap manufactured by injection molding is formed in the gate recess.

[0006] The pipe fitting according to claim 2, in claim 1, wherein the inner surface of the gate recess is the end face located on the pipe insertion side of the cap and is open in the axial direction of the cap.

[0007] The pipe fitting according to claim 3 is provided in claim 2, wherein an auxiliary recess is provided on the end face of the cap, which is connected to the open portion of the gate recess on the end face, and extends radially from the cap.

[0008] The pipe fitting according to claim 4 is characterized in that, in any one of claims 1 to 3, the inner surface of the gate recess is closed on the inner side, which is located on the opposite side of the pipe insertion side in the axial direction of the cap.

[0009] The pipe fitting according to claim 5 is characterized in that, in any one of claims 1 to 4, a pin gate is used in the injection molding, and the area of ​​the inner bottom surface of the gate recess is 5 times or more and 10 times or less the opening area of ​​the pin gate. [Brief explanation of the drawing]

[0010] [Figure 1] A semi-vertical cross-sectional view showing a resin pipe and a different type of pipe inserted into a pipe fitting. [Figure 2]Enlarged cross-sectional view showing a large amount of residual resin at the gate marks of the first and second caps. [Figure 3] A perspective view showing the shapes of the first and second caps. [Figure 4] This figure shows an alternative example, an enlarged cross-sectional view illustrating a state where there is a large amount of resin residue at the gate marks of the first and second caps. [Figure 5] A diagram illustrating an alternative example, showing a perspective view of the shapes of the first and second caps. [Modes for carrying out the invention]

[0011] The following describes one embodiment of the present invention. As shown in Figure 1, the substantially cylindrical pipe fitting body 11 constituting the pipe fitting 10 has a pair of engaging cylinder portions 13 that protrude on both sides on the outer circumference and guide cylinder portions 14 that protrude on both sides on the inner circumference. Between the pipe fitting body 11 and the guide cylinder portion 14, there is an insertion hole 16 into which a resin pipe 15 is inserted at one end (left side in the figure) and an adapter insertion hole 18 into which the inner end of an adapter 17 is inserted at the other end (right side in the figure). A water flow path 19 is formed inside the guide cylinder portion 14.

[0012] Multiple engagement protrusions 20 are provided on the outer circumferential surface of the pair of engagement cylinder portions 13. The first cap 21, which is connected to one end of the pipe joint body 11, and the second cap 22, which is connected to the other end, each have multiple engagement grooves 23 on their inner circumferential surface. The first cap 21 and the second cap 22 are fitted onto the engagement cylinder portion 13 of the pipe joint body 11, causing the engagement grooves 23 to engage with the engagement protrusions 20 of the engagement cylinder portion 13, thereby connecting the first cap 21 and the second cap 22 to the pipe joint body 11. An annular locking step 24 is provided on the inner circumferential surface of the engagement cylinder portion 13.

[0013] An intermediate cylindrical body 26 is disposed inside the engaging cylindrical portion 13, having an engaging stepped portion 25 that engages with the locking stepped portion 24. Between the outer end surface of the engaging cylindrical portion 13 and the inner circumferential surface of the first cap 21, a retaining ring 27, made of a metal such as stainless steel, is interposed as a retaining member, with its position restricted by a regulating body 28. A retaining piece 27a is formed to protrude diagonally from the inner circumference of the retaining ring 27, and is designed to bite into the outer circumference of the resin pipe 15 to prevent the resin pipe 15 from coming off. A split ring 29 is interposed between the retaining ring 27 and the inner circumferential surface of the first cap 21, and is configured to maintain the inclination angle of the retaining piece 27a.

[0014] The outer end surface of the split ring 29 has the same inclination angle as the inner circumferential surface of the first cap 21, and is configured to reduce the diameter of the split ring 29 when it is subjected to an outward force in the axial direction via the retaining piece 27a due to the force pulling out the resin pipe 15. The tightening surface 30 provided on the inner circumferential surface of the split ring 29 tightens the resin pipe 15. A first seal ring 31 made of rubber is placed between the pipe joint body 11 and the intermediate cylindrical body 26, and is designed to tightly seal the outer circumferential surface of the inserted resin pipe 15 to prevent water leakage.

[0015] An insertion guide 32 is positioned inside the split ring 29, which is pressed against the tip of the resin pipe 15 to guide its insertion. The insertion guide 32 is formed in the shape of a C-ring and is configured to be expandable and contractible. The outer diameter of the insertion guide 32 is the same as or slightly larger than the outer diameter of the resin pipe 15, and its inner diameter is slightly larger than the outer diameter of the guide cylinder portion 14. A retaining step is provided on the inner circumferential surface of the split ring 29, and the outer circumference of the outer end surface of the insertion guide 32 engages with this retaining step, thereby preventing the insertion guide 32 from coming loose and holding it in place.

[0016] An arcuate surface is formed on the inner end of the insertion guide 32, allowing it to move smoothly when it moves inward along the outer circumferential surface of the guide cylinder 14. Furthermore, when the insertion guide 32 moves as the resin pipe 15 is inserted and comes into sliding contact with the retaining piece 27a of the retaining ring 27 and the first seal ring 31, the retaining piece 27a and the first seal ring 31 are gradually expanded in diameter, while the insertion guide 32 itself is reduced in diameter.

[0017] A locking groove 40 is formed on the outer circumferential surface of the first cap 21, and a stainless steel retaining ring 41 is attached to the outer circumferential surface of the base end of the first cap 21, with its locking claws 43 at the tip engaging with the locking groove 40 of the first cap 21. This maintains the connection of the first cap 21 to the pipe fitting body 11.

[0018] On the second cap 22 side of the pipe fitting body 11, a rubber second seal ring 33 is positioned between the pipe fitting body 11 and the intermediate cylindrical body 26, and is designed to tightly seal the outer circumferential surface of the inner end of the inserted adapter 17 to prevent water from entering. The inner circumferential surface of the tip of the second cap 22 is provided with a locking portion 34, which is a tapered surface that narrows in diameter towards the tip. No retaining ring 27, split ring 29, or other retaining members are provided on this second cap 22 side.

[0019] The adapter 17 is formed in a nearly cylindrical shape, with its inner end inserted into the adapter insertion hole 18, and a different type of pipe 36 made of polyvinyl chloride resin connected by adhesive within the enlarged diameter portion 35 of the outer end. The outer peripheral surface of the central part of the adapter 17 is provided with an engaging portion 37 having a mountain-shaped (triangular cross-section), and this engaging portion 37 engages with a locking portion 34 on the inner peripheral surface of the tip of the second cap 22, so that the adapter 17 is held in place by the second cap 22 and does not come off. The engaging portion 37 is composed of an inclined surface 38 on the inner end side and a slanted surface 39 on the outer end side, and the inclination angle of the slanted surface 39 is set to be greater than the inclination angle of the inclined surface 38. On the other hand, the inclination angle of the tapered surface forming the locking portion 34 of the second cap 22 is set to be approximately the same as the inclination angle of the slanted surface 39 of the engaging portion 37.

[0020] That is, it is easy to insert the adapter 17 into the adapter insertion hole 18, and after the engaging portion 37 of the adapter 17 engages with the locking portion 34 of the second cap 22, it is difficult for the adapter 17 to come out of the second cap 22. Therefore, by inserting the inner end portion of the adapter 17 into the adapter insertion hole 18 of the pipe joint body 11, the engaging portion 37 of the adapter 17 hits the tip portion of the second cap 22, elastically deforms the second cap 22, and the engaging portion 37 can be easily engaged with the locking portion 34 of the second cap 22.

[0021] A locking groove 40 is formed on the outer peripheral surface of the second cap 22, and a stainless steel retaining ring 41 is attached to the outer periphery of the base end portion of the second cap 22 in a state where its locking claw 43 on the tip side is locked to the locking groove 40 of the second cap 22. And the connection of the second cap 22 to the pipe joint body 11 is maintained.

[0022] The first cap 21, the second cap 22, the adapter 17, the pipe joint body 11, the intermediate cylinder 26, the split ring 29, the insertion guide 32, etc. are formed of synthetic resins such as polyacetal (POM), polyphenylene sulfide (PPS) [these are engineering plastics], vinyl chloride resin, etc. In this case, it is preferable in terms of adhesiveness that the adapter 17 is formed of the same material as the dissimilar pipe 36.

[0023] Incidentally, the pipe joint body 11 can also be formed of a metal such as an alloy (brass, bronze, etc.). Further, the resin pipe 15 is formed of a polyolefin resin such as cross-linked polyethylene or polybutene. Furthermore, the dissimilar pipe 36 is formed of a metal such as copper or a copper alloy in addition to a synthetic resin such as vinyl chloride resin. By the way, when the dissimilar pipe 36 is a metal such as copper or a copper alloy, the adapter 17 is formed of a metal such as brass, and the dissimilar pipe 36 is adhered to the adapter 17 by brazing.

[0024] As shown in Figures 2 and 3, gate recesses 44 are formed on the inner circumferential surfaces 49 of the insertion openings 48 of the first cap 21 and the second cap 22. The gate recess 44 comprises two inner walls 44a and 44b extending in the axial direction of the caps 21 and 22, one inner wall 44c extending in the circumferential direction of the caps 21 and 22, and an inner bottom surface 44d. In other words, the inner surface of the gate recess 44 of the caps 21 and 22 is open in the axial direction of the caps 21 and 22 at the end face located on the insertion side of the pipe (resin pipe 15, adapter 17), while the inner side on the opposite side from the insertion side is closed by the inner wall 44c.

[0025] In the caps 21 and 22, an auxiliary recess 45 is formed on the end face located on the insertion side of the pipe (resin pipe 15, adapter 17), which connects to a gate recess 44. The auxiliary recess 45 has two parallel inner walls 45a and 45b that extend from the inner circumferential surface 49 to the outer circumferential surface of the insertion opening 48 of the caps 21 and 22. The inner walls 45a and 45b are connected to the inner walls 44a and 44b of the gate recess 44, respectively.

[0026] Gate marks 46 of caps 21 and 22, manufactured by injection molding using a pin gate 47, are formed within the gate recess 44. The gate marks 46 are located in the circumferential center of caps 21 and 22 on the inner bottom surface 44d of the gate recess 44. The area of ​​the inner bottom surface 44d is set to be at least 5 times and no more than 10 times the opening area of ​​the pin gate 47.

[0027] Next, the operation of the pipe joint 10 configured as described above will be explained. As shown in Figure 1, when the inner end of the adapter 17 is inserted through the opening of the second cap 22 and fitted into the guide tube portion 14, the engaging portion 37 of the adapter 17 contacts the tip of the second cap 22. Subsequently, when the adapter 17 is inserted further, its inner end enters the adapter insertion hole 18, and at the same time, the inclined surface 38 of the engaging portion 37 comes into contact with the inner circumference of the tip of the second cap 22, causing the tip of the second cap 22 to expand in diameter due to elastic deformation. At this time, the outer circumferential surface of the inner end of the adapter 17 slides against the second seal ring 33, sealing the gap between the pipe fitting body 11 and the adapter 17.

[0028] Next, when the adapter 17 is further inserted, the engaging portion 37 of the adapter 17 enters the inside of the second cap 22, and the beveled surface 39 of the engaging portion 37 engages all around the tapered surface that forms the locking portion 34 of the second cap 22. As a result, the adapter 17 is prevented from coming off the second cap 22, or in other words, the pipe fitting body 11. The assembly of the adapter 17 to the pipe fitting body 11 as described above can be done in advance at the factory, or it can be done on-site when connecting the resin pipe 15 and a different type of pipe 36.

[0029] With the adapter 17 assembled to the pipe fitting body 11, when the resin pipe 15 is inserted through the insertion opening of the first cap 21, the tip surface of the resin pipe 15 comes into contact with the insertion guide 32. If the resin pipe 15 is inserted further from this state, it is guided by the insertion guide 32, and the insertion guide 32 and the resin pipe 15 pass through the retaining piece 27a of the retaining ring 27, and the tip of the insertion guide 32 reaches the first seal ring 31. At this time, since an arcuate surface is formed on the inner end side of the insertion guide 32, this arcuate surface slides against the retaining piece 27a, gradually expanding the diameter of the retaining piece 27a, while the insertion guide 32 itself shrinks in diameter. Therefore, the insertion guide 32 and the resin pipe 15 can pass through the retaining ring 27 smoothly.

[0030] Then, the tip of the insertion guide 32 is inserted into the inner end of the insertion hole 16. At this time, since an arcuate surface is formed on the inner end of the insertion guide 32, this arcuate surface slides against the first seal ring 31, gradually expanding the diameter of the first seal ring 31, while the insertion guide 32 itself shrinks in diameter. Therefore, the insertion guide 32 and the resin pipe 15 pass smoothly through the first seal ring 31, and water is sealed between them.

[0031] Afterward, adhesive is applied to the outer surface of the end of the dissimilar pipe 36 made of polyvinyl chloride resin, and then it is inserted into the enlarged diameter portion 35 of the adapter 17, thereby joining the dissimilar pipe 36 to the adapter 17. In this way, the resin pipe 15 is connected to one end of the pipe fitting 10 equipped with the adapter 17, and the dissimilar pipe 36 is connected to the other end.

[0032] The effects achieved by the above embodiments are summarized below. In the pipe fitting 10, the engaging portion 37 provided on the outer circumference of the adapter 17 engages with the locking portion 34 provided on the inner circumference of the second cap 22 to prevent it from coming loose. Therefore, the adapter 17 can be prevented from coming loose with a simple operation of inserting the adapter 17 into the pipe fitting body 11 and engaging its engaging portion 37 with the locking portion 34 of the second cap 22. In addition, retaining members such as a retaining ring 27 and a split ring 29 are omitted on the second cap 22 side of the pipe fitting 10. As a result, the structure of the pipe fitting 10 can be simplified and assembly can be made easier, manufacturing costs can be reduced, and the connection between the resin pipe 15 and a different type of pipe 36 can be made easier.

[0033] The second cap 22 is configured to be elastically deformable, and when the inner end of the adapter 17 is inserted into the adapter insertion hole 18 of the pipe fitting body 11, the elastic deformation of the second cap 22 engages the engaging portion 37 of the adapter 17 with the locking portion 34 of the second cap 22, preventing the adapter 17 from coming off. Therefore, by utilizing the elastic deformation of the second cap 22 and simply inserting the adapter 17 into the adapter insertion hole 18, the adapter 17 can be easily connected to the pipe fitting body 11.

[0034] A retaining ring 41 is attached to the outer circumference of the base end of the second cap 22 to maintain the connection of the second cap 22 to the pipe fitting body 11. Therefore, the connection of the second cap 22 to the pipe fitting body 11 can be maintained for a long period of time.

[0035] In the first cap 21 and the second cap 22, a gate recess 44 is formed on the inner circumferential surface 49 of the insertion opening 48, and gate marks 46 for each cap 21 and 22 are formed within the gate recess 44. Therefore, the gate marks 46 and the sealing surface (the outer circumferential surface of the resin pipe 15 and the outer circumferential surface of the inner end of the adapter 17) can be separated by the depth of the gate recess 44. Consequently, even if there is a lot of resin residue in the gate marks 46, it is possible to prevent the gate marks 46 and the sealing surface from rubbing against each other strongly, thereby preventing a decrease in watertightness.

[0036] The inner surface of the gate recess 44 is open in the axial direction of the caps 21 and 22 at the end faces located on the insertion side of the pipes (resin pipes 15 and adapters 17) in the first cap 21 and the second cap 22. As a result, the rigidity of the caps 21 and 22 is reduced at the open portion at the end face, making them easier to deform. Therefore, the stress caused by the pipes (resin pipes 15 and adapters 17) rubbing against the gate mark 46 can be relieved by the deformation of the caps 21 and 22 that is allowed at the open portion at the end face, and strong rubbing between the gate mark 46 and the outer surfaces of the pipes 15 and 17 can be more effectively prevented. In addition, an auxiliary recess 45 connected to the gate recess 44 is provided on the end faces of the caps 21 and 22 located on the insertion side of the pipes 15 and 17, extending in the radial direction of the caps 21 and 22. Therefore, the reduced rigidity in the auxiliary recess 45 makes the deformation of the caps 21 and 22 easier, and more effectively prevents strong friction between the gate mark 46 and the outer surfaces of the pipes 15 and 17.

[0037] The inner surface of the gate recess 44 is closed by an inner wall 44c on the far side opposite to the insertion side of the pipe (resin pipe 15 and adapter 17) in the first cap 21 and the second cap 22. Therefore, it is possible to prevent foreign matter from entering the inside of the pipe fitting 10 through the gate recess 44.

[0038] The area of ​​the inner bottom surface 44d is set to be at least 5 times and no more than 10 times the opening area of ​​the pin gate 47. If the area of ​​the inner bottom surface 44d is at least 5 times the opening area of ​​the pin gate 47, the stress caused by the pipe (resin pipe 15 and adapter 17) rubbing against the gate mark 46 can be sufficiently relieved by the deformation of the gate mark 46 that is permissible in the gate recess 44. If the area of ​​the inner bottom surface 44d is no more than 10 times the opening area of ​​the pin gate 47, the deformation of the pipe (resin pipe 15 and adapter 17) into the gate recess 44 and excessive interference with the gate mark 46 can be suppressed.

[0039] (Another example) Furthermore, the above embodiments can be modified and implemented as follows. In the above-described embodiment, the inner surface of the gate recess 44 was open in the axial direction of the caps 21 and 22, with the end face located on the insertion side of the pipe (resin pipe 15 and adapter 17) in the first cap 21 and the second cap 22. However, the inner surface of the gate recess 44 may be configured not to be open.

[0040] In the above-described embodiment, an auxiliary recess 45 connected to a gate recess 44 was provided on the end face of each cap 21, 22 that is located on the insertion side of the pipe (resin pipe 15 and adapter 17), extending radially from each cap 21, 22. However, a configuration without the auxiliary recess 45 is also possible.

[0041] In the above-described embodiment, the inner surface of the gate recess 44 was closed by an inner wall 44c on the rear side opposite to the insertion side of the pipe (resin pipe 15 and adapter 17) in the caps 21 and 22. However, the inner surface of the gate recess 44 may be configured such that the rear side is open in the axial direction of the caps 21 and 22.

[0042] In the above-described embodiment, the area of ​​the inner bottom surface 44d of the gate recess 44 was set to be 5 times or more and 10 times or less the opening area of ​​the pin gate 47. However, the area of ​​the inner bottom surface 44d may be less than 5 times the opening area of ​​the pin gate 47, or it may be more than 10 times.

[0043] In another embodiment shown in Figures 4 and 5, a gate recess 44 is formed on the outer circumferential surface of the caps 21 and 22 near the insertion opening 48. A gate mark 46 is formed inside the gate recess 44, i.e., on the outer circumferential surface of the caps 21 and 22. Therefore, since the gate mark 46 is not on the inner circumferential surface 48 of the caps 21 and 22 and the gate mark 46 is hidden by the gate recess 44, even if there is a lot of resin residue in the gate mark 46, it is possible to prevent the gate mark 46 from rubbing against the sealing surface (the outer circumferential surface of the resin pipe 15 and the outer circumferential surface of the inner end of the adapter 17), thereby preventing a decrease in watertightness. In addition, since the gate mark 46 is hidden by the gate recess 44, even if an excessive gate mark 46 is created, it is possible to prevent the appearance from deteriorating. Note that "the outer circumferential surface of the caps 21 and 22 near the insertion opening 48" refers to the area on the outer circumferential surface that is closer to the insertion opening 48 than the maximum outer diameter portion of the caps 21 and 22.

[0044] (Note) The technical concepts that can be understood from the above embodiments are described below. (1) A pipe fitting comprising a fitting body, a synthetic resin cap attached to the fitting body which defines a pipe insertion space with the fitting body and has an insertion opening for inserting the pipe into the insertion space, a retaining member disposed in the insertion space to prevent the pipe inserted into the insertion space from coming out, and a sealing member disposed in the insertion space which contacts the outer surface of the pipe inserted into the insertion space to ensure watertightness, wherein a gate recess is formed on the outer surface of the cap near the insertion opening, and a gate mark of the cap manufactured by injection molding is formed in the gate recess.

[0045] (2) The pipe fitting according to the technical concept (1), wherein the inner surface of the gate recess is the end face located on the insertion side of the pipe in the cap and is open in the axial direction of the cap.

[0046] (3) The pipe fitting according to the technical concept (2), wherein an auxiliary recess is provided on the end face of the cap, extending in the radial direction of the cap and connected to the open portion of the gate recess on the end face.

[0047] (4) The inner surface of the gate recess is closed on the inner side that is on the opposite side from the insertion side of the pipe in the axial direction of the cap, as described in any one of the technical concepts (1) to (3).

[0048] (5) A pipe fitting according to any one of the technical concepts (1) to (4), wherein a pin gate is used in the injection molding, and the area of ​​the inner bottom surface of the gate recess is 5 times or more and 10 times or less the opening area of ​​the pin gate.

[0049] (6) A pipe fitting comprising a fitting body, a synthetic resin cap attached to the fitting body which defines a pipe insertion space with the fitting body and has an insertion opening for inserting the pipe into the insertion space, a retaining member disposed in the insertion space to prevent the pipe inserted into the insertion space from coming out, and a sealing member disposed in the insertion space which contacts the outer surface of the pipe inserted into the insertion space to ensure watertightness, wherein a gate recess is formed on the inner surface of the insertion opening, and a gate mark of the cap manufactured by injection molding is formed in the gate recess.

[0050] (7) The pipe fitting according to the technical concept (6), wherein the inner surface of the gate recess is the end face located on the insertion side of the pipe in the cap and is open in the axial direction of the cap.

[0051] (8) The pipe fitting according to the technical concept (7), wherein an auxiliary recess is provided on the end face of the cap, extending in the radial direction of the cap and connected to the open portion of the gate recess on the end face.

[0052] (9) The inner surface of the gate recess is closed on the inner side opposite to the insertion side of the pipe in the axial direction of the cap, as described in any one of the technical concepts (6) to (8).

[0053] (10) A pipe fitting according to any one of the technical concepts (6) to (9), wherein a pin gate is used in the injection molding, and the area of ​​the inner bottom surface of the gate recess is 5 times or more and 10 times or less the opening area of ​​the pin gate. [Explanation of symbols]

[0054] 10...Pipe fitting, 11...Pipe fitting body, 15...Resin pipe, 16...Insertion hole, 17...Adapter, 18...Adapter insertion hole, 21...First cap, 22...Second cap, 27...Retaining member, 31...First seal ring, 33...Second seal ring, 34...Locking part, 36...Different pipes, 37...Engaging part, 41...Retaining ring, 44...Gate recess, 45...Auxiliary recess, 46...Gate mark, 47...Pin gate, 48...Insertion opening, 49...Inner circumferential surface.

Claims

[Claim 1] A pipe fitting comprising: a fitting body; a synthetic resin cap attached to the fitting body, defining a pipe insertion space with the fitting body and having an insertion opening for inserting the pipe into the insertion space; a retaining member disposed in the insertion space to prevent the pipe inserted into the insertion space from coming out; and a sealing member disposed in the insertion space to contact the outer surface of the pipe inserted into the insertion space to ensure watertightness, wherein a gate recess is formed on the outer surface of the cap near the insertion opening, and a gate mark of the cap manufactured by injection molding is formed within the gate recess. The inner surface of the gate recess is the end face located on the pipe insertion side of the cap and is open in the axial direction of the cap. A pipe fitting wherein an auxiliary recess is provided on the end face of the cap, extending radially from the cap and connected to the open portion of the gate recess at the end face.

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