Resin elbow joint manufacturing equipment

Abstract

To provide a device for manufacturing a resin elbow joint capable of suppressing a decrease in flow rare at a fluid supply faucet at an end of a fluid supply system.SOLUTION: Provided is a device for manufacturing a resin elbow joint, in which a resin elbow joint 1 having an L-shaped corner part 4 integrally formed on both straight parts 2 and 3 so as to connect each other, is formed by injection molding. A step part 12 for regulating an insertion position of a pipe connected to either of the straight parts 2 and 3 is formed on an inner peripheral surface of either of the straight parts 2 and 3. A pair of pins 25 and 26 for molding the inner peripheral surface of either of the straight parts 2 and 3, the step part 12 and the inner peripheral surface of the corner part 4 is arranged on a mold 24, and the pins 25 and 26 are divided such that a parting line is applied to a portion for molding a projecting corner portion of the step part 12.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a manufacturing apparatus for a resin elbow joint. [Background technology]

[0002] In fluid supply systems such as building water supply systems, multiple pipes for carrying fluids (such as water) are provided, and a plastic elbow joint is known that connects pipes extending at approximately right angles to each other. As shown in Patent Document 1, the plastic elbow joint includes a plastic joint body having an L-shaped corner portion integrally formed with a first straight section and a second straight section to connect the first and second straight sections. The first straight section of the joint body is provided with a first locking mechanism for preventing the first pipe connected to the first straight section from coming loose. The second straight section of the joint body is provided with a second locking mechanism for preventing the second pipe connected to the second straight section from coming loose. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Design Registration No. 1474055 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a building is renovated or otherwise installed, if the piping is laid out to avoid the building's structural components, the number of bent pipes, i.e., the number of parts where plastic elbow joints are installed, increases. As a result, the number of plastic elbow joints installed in the fluid supply system increases, and the pressure loss caused by the fluid passing through the corners of those plastic elbow joints increases, resulting in a decrease in the flow rate of the fluid at the fluid supply valve at the end of the fluid supply system.

[0005] The object of the present invention is to provide a manufacturing device for a plastic elbow fitting that can prevent a decrease in the fluid flow rate at the fluid supply valve at the end of a fluid supply system when the number of plastic elbow fittings installed in the fluid supply system is increased. [Means for solving the problem]

[0006] In order to achieve the above object, the manufacturing apparatus for a resin elbow fitting according to claim 1 of the present invention is a manufacturing apparatus for a resin elbow fitting that forms, by injection molding, a resin elbow fitting having a resin fitting body having an L-shaped corner portion that is integrally formed with a first straight portion and a second straight portion so as to connect them, the resin elbow joint includes a first locking mechanism that prevents the first upstream pipe connected to the first straight section from coming loose; a second locking mechanism that prevents a downstream second pipe connected to the second straight section from coming off; Equipped with an accommodation portion that accommodates an end portion of the first piping is provided in a portion of an inner circumferential surface of the first straight portion near the corner portion, and a step portion that defines an insertion position of the first piping is formed between the inner circumferential surface of the accommodation portion and an inner circumferential surface of an inlet portion at the corner portion; an accommodation portion that accommodates an end portion of the second piping is provided in a portion of the inner circumferential surface of the second straight portion near the corner portion, and a step portion that defines an insertion position of the second piping is formed between the inner circumferential surface of the accommodation portion and an inner circumferential surface of an outlet portion at the corner portion; a pair of pins for molding the inner circumferential surfaces of the accommodating portions, the step portions, and the corner portions are arranged in the injection molding die, and each of the pins is removable from the die; A manufacturing device for a plastic elbow joint, in which each pin is divided so that the parting line overlaps the part for molding the protruding corner portion of the step portion that is the boundary between each step portion and the corresponding corner portion. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 4 is a cross-sectional view showing a resin elbow joint and a pipe cover that covers the joint. [Figure 2] FIG. [Figure 3] FIG. 3 is a cross-sectional view showing a resin elbow joint. [Figure 4] FIG. 4 is a cross-sectional view showing a mold for forming a joint body of a resin elbow joint. [Figure 5] FIG. 4 is a cross-sectional view showing a mold for forming a joint body of a resin elbow joint. [Figure 6] FIG. 3 is a cross-sectional view showing a resin elbow joint. [Figure 7] FIG. 4 is a cross-sectional view showing a mold for forming a joint body of a resin elbow joint. [Figure 8] FIG. 10 is a cross-sectional view showing another example of a resin elbow joint. DETAILED DESCRIPTION OF THE INVENTION

[0008] [First embodiment] A first embodiment of a resin elbow joint will be described below with reference to FIGS. The resin elbow fitting 1 shown in Figure 1 is used to connect pipes that extend at a right angle among multiple pipes (pipes) for carrying water in a building's water supply system, etc. This resin elbow fitting 1 includes a resin fitting body 5 having an L-shaped corner portion 4 that is integrally formed with a first straight section 2 and a second straight section 3 to connect them. The resin that can be used to form the fitting body 5 may be, for example, a mixture of polyphenylene sulfide resin and glass fiber.

[0009] In the joint body 5, the first straight portion 2 and the second straight portion 3 are formed into cylindrical shapes that extend linearly in directions perpendicular to each other, and the corner portion 4 is formed into a cylindrical shape that curves in an arc so as to connect the first straight portion 2 and the second straight portion 3. The first straight portion 2 is provided with a first locking mechanism 7 that prevents a pipe 6 (first piping) connected to the first straight portion 2 from coming off. Furthermore, the second straight portion 3 is provided with a second locking mechanism 9 that prevents a pipe 8 (second piping) connected to the second straight portion 3 from coming off.

[0010] The resin elbow fitting 1 is designed to have an equivalent pipe length of less than 1.0 m, more specifically, an equivalent pipe length of less than 0.8 m. Here, the equivalent pipe length is a value that represents the pressure loss when a fluid (water in this example) passes through the resin elbow fitting 1, and the smaller the pressure loss, the smaller the value. This equivalent pipe length can be calculated by the following steps (A) to (C).

[0011] (A) Measure the pressure difference between upstream and downstream of the elbow fitting when a constant flow of water is passed through the elbow fitting. (B) Calculate in advance the pipe friction loss per meter in a straight pipe with an inner diameter that fits the elbow fitting when water is passed through the pipe at the same flow rate as the constant flow rate passed through the elbow fitting in (A) above.

[0012] (C) Divide the pressure difference measured in (A) above by the friction loss per meter of pipe in (B) above, and use the resulting value as the equivalent pipe length of the elbow joint. As shown in Figure 2, when the resin elbow fitting 1 is installed as part of a building's water supply system, it is entirely covered by a piping cover 10. As shown in Figure 1, the piping cover 10 includes a first cover part 10a that extends in the same direction as the first straight part 2 of the fitting body 5 and covers the first straight part 2 and the first locking mechanism 7, and a second cover part 10b that extends in the same direction as the second straight part 3 of the fitting body 5 and covers the second straight part 3 and the second locking mechanism 9.

[0013] Furthermore, the pipe cover 10 is provided with a corner cover portion 10c that connects the first cover portion 10a and the second cover portion 10b. This corner cover portion 10c covers the corner portion 4 of the joint body 5 and is curved along the corner portion 4. The curvature of the corner portion 4 of the joint body 5 is smaller than the curvature of the corner cover portion 10c of the pipe cover 10. This allows the portion of the space between the pipe cover 10 and the joint body 5 inside the pipe cover 10 that corresponds to the corner portion 4 of the joint body 5 to be larger, which is advantageous when using this portion as a heat-insulating space, etc.

[0014] Next, the structure of the resin elbow joint 1 will be described in detail. As shown in FIG. 3 , in the fitting body 5 of the resin elbow fitting 1, the boundary between the corner portion 4 and the first straight portion 2 is the inlet portion 4a. A housing portion 11 is provided on the inner circumferential surface of the first straight portion 2 near the corner portion 4 to house the end of the upstream pipe 6, out of the pipes 6 and 8. A step portion 12 is formed between the inner circumferential surface of the housing portion 11 and the inner circumferential surface of the inlet portion 4a in the corner portion 4, and the step portion 12 and the inner circumferential surface of the inlet portion 4a are substantially perpendicular to each other. A cylindrical metal incore 13 is inserted into the end of the pipe 6. A flange 13a formed on the end of the incore 13 prevents the incore 13 from sinking into the pipe 6. The end of the pipe 6 is inserted from the end of the first straight portion 2 into the inner circumferential surface of the incore 11 in the first straight portion 2 until the incore 13 inserted into the end of the pipe 6 abuts against the step portion 12.

[0015] A seal portion 14, which has a larger diameter than the accommodation portion 11, is provided on the inner peripheral surface of the first straight portion 2 in a portion between the accommodation portion 11 and the end portion of the first straight portion 2. A seal ring 15, a spacer 16, a seal ring 17, and a retaining ring 18 are arranged in this seal portion 14 in this order from the accommodation portion 11 side toward the end portion of the first straight portion 2. When the end portion of the pipe 6 is inserted into the accommodation portion 11 of the first straight portion 2, the pipe 6 passes through the seal ring 15, the spacer 16, the seal ring 17, and the retaining ring 18. At this time, the seal rings 15 and 17 in the seal portion 14 are in contact with the outer peripheral surface of the pipe 6, thereby preventing water flowing inside the fitting body 5 from leaking out of the resin elbow fitting 1 from between the outer peripheral surface of the pipe 6 and the inner peripheral surface of the seal portion 14.

[0016] The first locking mechanism 7 includes a retaining member 19 for holding the pipe 6 in the first straight section 2, and a cap 20 for attaching the retaining member 19 to the first straight section 2. The retaining member 19 is provided with an annular locking ring 23 located between an insert ring 21 and a split ring 22. The retaining member 19 is located adjacent to a retaining ring 18 arranged in the seal section 14 of the first straight section 2.

[0017] The cap 20 is formed in a cylindrical shape. A split ring 22 and a lock ring 23 are disposed inside the cap 20, and the fitting ring 21 is further fitted inside the cap 20, thereby preventing the split ring 22 and the lock ring 23 from falling out of the inside of the cap 20. In this state, the first locking mechanism 7, consisting of the cap 20 and the retaining member 19, can be easily assembled to the first straight portion 2 by engaging the open end of the cap 20 with the end of the first straight portion 2 at a portion that radially overlaps the end of the first straight portion 2.

[0018] With the first locking mechanism 7 (retaining member 19 and cap 20) attached to the first straight section 2, when the end of the pipe 6 penetrates the retaining member 19 and the cap 20 and is inserted into the accommodation section 11 from the end of the first straight section 2, the locking ring 23 of the retaining member 19 presses against the outer circumferential surface of the pipe 6. This prevents the pipe 6 from slipping out of the first straight section 2.

[0019] Meanwhile, in the joint body 5 of the plastic elbow joint 1, the second straight section 3 and the second locking mechanism 9 have substantially the same configuration as the first straight section 2 and the first locking mechanism 7, respectively. For this reason, in the following description of the second straight section 3 and the second locking mechanism 9, the same parts as the first straight section 2 and the first locking mechanism 7 will be described using the same reference numerals as those of the first straight section 2 and the first locking mechanism 7.

[0020] In the joint body 5, the boundary between the corner portion 4 and the second straight portion 3 is the outlet portion 4b. A housing portion 11 is provided on the inner circumferential surface of the second straight portion 3 near the corner portion 4 to house the downstream end of the pipe 8. A step portion 12 is formed between the inner circumferential surface of the housing portion 11 and the inner circumferential surface of the outlet portion 4b in the corner portion 4, and the step portion 12 and the inner circumferential surface of the outlet portion 4b are substantially perpendicular to each other. An inner core 13 is inserted into the end of the pipe 8. A flange 13a prevents the inner core 13 from sinking into the pipe 8. The end of the pipe 8 is inserted from the end of the second straight portion 3 into the inner circumferential surface of the housing portion 11 in the second straight portion 3 until the inner core 13 inserted into the end of the pipe 8 abuts against the step portion 12.

[0021] A seal portion 14 having a larger diameter than the accommodation portion 11 is provided on the inner peripheral surface of the second straight portion 3 in a portion between the accommodation portion 11 and the end portion of the second straight portion 3. A seal ring 15, a spacer 16, a seal ring 17, and a retaining ring 18 are arranged in this seal portion 14 in this order from the accommodation portion 11 side toward the end portion of the second straight portion 3. When the end portion of the pipe 8 is inserted into the accommodation portion 11 of the second straight portion 3, the pipe 8 passes through the seal ring 15, the spacer 16, the seal ring 17, and the retaining ring 18. At this time, the seal rings 15 and 17 in the seal portion 14 are in contact with the outer peripheral surface of the pipe 8, thereby preventing water flowing inside the fitting body 5 from leaking out of the resin elbow fitting 1 from between the outer peripheral surface of the pipe 8 and the inner peripheral surface of the seal portion 14.

[0022] The second locking mechanism 9 includes a retaining member 19 for holding the pipe 8 in the second straight section 3, and a cap 20 for attaching the retaining member 19 to the second straight section 3. The retaining member 19 is provided with an annular locking ring 23 located between an insert ring 21 and a split ring 22. The retaining member 19 is located adjacent to a retaining ring 18 arranged in the seal section 14 of the second straight section 3.

[0023] The cap 20 is formed in a cylindrical shape. A split ring 22 and a lock ring 23 are disposed inside the cap 20, and the fitting ring 21 is further fitted into the cap 20, thereby preventing the split ring 22 and the lock ring 23 from falling out of the cap 20. In this state, the second lock mechanism 9, consisting of the cap 20 and the retaining member 19, can be easily assembled to the second straight portion 3 by engaging the open end of the cap 20 with the end of the second straight portion 3 at a portion that radially overlaps the end of the second straight portion 3.

[0024] With the second locking mechanism 9 (retaining member 19 and cap 20) attached to the second straight section 3, when the end of the pipe 8 penetrates the retaining member 19 and the cap 20 and is inserted into the accommodation section 11 from the end of the second straight section 3, the locking ring 23 of the retaining member 19 presses against the outer circumferential surface of the pipe 8. This prevents the pipe 8 from slipping out of the second straight section 3.

[0025] Next, the corner portion 4 of the joint body 5 will be described in detail. The corner portion 4 has a vertex 4c at a midpoint between the inlet portion 4a and the outlet portion 4b. The inner peripheral surfaces of the inlet portion 4a, the outlet portion 4b, and the vertex 4c are each perfectly circular. The inner peripheral surface of the inlet portion 4a smoothly connects with the inner peripheral surface of the vertex 4c within the corner portion 4, and the inner peripheral surface of the vertex 4c smoothly connects with the inner peripheral surface of the outlet portion 4b. The inner diameters of the inlet portion 4a and the outlet portion 4b are larger than the inner diameter of the vertex 4c. Therefore, the inner diameter of the corner portion 4 gradually increases from the vertex 4c toward the inlet portion 4a and gradually increases from the vertex 4c toward the outlet portion 4b. This structure of the corner portion 4 ensures that the equivalent pipe length of the plastic elbow fitting 1 is less than 1.0 m, more specifically, less than 0.8 m.

[0026] Next, a method for manufacturing the resin elbow joint 1, more specifically, a method for forming the joint body 5, will be described. 4 shows a mold 24 for forming the joint body 5 by injection molding. A pair of pins 25, 26 extending in directions perpendicular to each other are arranged inside the clamped mold 24. The pins 25, 26 include a main body block 27 that can be pulled out of the mold 24, and a movable block 28 provided at the tip of the main body block 27. The main body block 27 and movable block 28 are connected by a connecting bar 30.

[0027] A cylindrical body 27a is inserted inside the main body block 27, and a coil spring 27b is provided between the cylindrical body 27a and the main body block 27. The connecting bar 30 is inserted inside the main body block 27 and extends between the interior of the movable block 28 and the interior of the cylindrical body 27a. One end of the connecting bar 30 is rotatably connected to a support shaft 31 fixed to the movable block 28, and the other end of the connecting bar 30 is rotatably connected to a support shaft 33 that passes through the cylindrical body 27a. The support shaft 33 also passes through a slit 32 formed in the main body block 27 so as to extend in the same direction as the connecting bar 30.

[0028] Within the mold 24, the movable block 28 of the pin 25 and the movable block 28 of the pin 26 are butted against each other. In other words, the tips of the pins 25, 26 are butted against each other. Then, molten resin is injected into cavities around the pins 25, 26 within the mold 24 and the resin is solidified around the pins 25, 26 to form the joint body 5. More specifically, the first straight portion 2 of the joint body 5 is formed around the body block 27 of the pin 25, the corner portions 4 of the joint body 5 are formed around the movable blocks 28 of the pins 25, 26, and the second straight portion 3 of the joint body 5 is formed around the body block 27 of the pin 26. Then, as the mold 24 is opened, the pins 25, 26 are pulled out in a direction that separates the movable blocks 28.

[0029] FIG. 5 shows the state in which the pins 25, 26 have been extracted as described above. In this process of extracting the pins 25, 26, first, only the main body block 27 moves within the slit 32 within the range in which the support shaft 33 can be displaced relative to the main body block 27. As a result, the main body block 27 of the pin 25 is extracted from the first straight portion 2 of the joint body 5, and the main body block 27 of the pin 26 is extracted from the second straight portion 3. The main body block 27 moves relative to the cylindrical body 27a and against the elastic force of the coil spring 27b. When the support shaft 33 connected to the connecting bar 30 subsequently contacts the end of the slit 32 of the main body block 27, the movable block 28 (support shaft 31) is pulled by the main body block 27 via the connecting bar 30. The pulled movable block 28 rotates around the center line of the support shaft 31 connected to the connecting bar 30 and is extracted from the corner portion 4 of the joint body 5. When the movable block 28 is pulled out in this manner, the main body block 27 and the movable block 28 can return to a state in which they are close to each other due to the elastic force of the coil spring 27b.

[0030] The inner diameter of the corner portion 4 gradually increases from the apex portion 4c toward the inlet portion 4a, and also gradually increases from the apex portion 4c toward the outlet portion 4b, making it easy to pull the movable block 28 out of the corner portion 4. Furthermore, the inner peripheral surface of the inlet portion 4a and the step portion 12 are approximately perpendicular to each other, and the inner peripheral surface of the outlet portion 4b and the step portion 12 are also approximately perpendicular to each other. However, if the intersections between the inlet portion 4a and the step portion 12 and the outlet portion 4b and the step portion 12 were to be rounded, this would result in a problem in that the outer shape of the movable block 28 and its movement during removal would have to be complicated. However, this problem does not arise because the inner peripheral surface of the inlet portion 4a and the step portion 12 are perpendicular to each other, and the inner peripheral surface of the outlet portion 4b and the step portion 12 are also perpendicular to each other.

[0031] According to the present embodiment described above in detail, the following advantageous effects can be obtained. (1) Because the equivalent pipe length of the resin elbow fitting 1 is a small value of less than 1.0 m, more specifically less than 0.8 m, even if the number of resin elbow fittings 1 in a water supply system increases due to building renovations, etc., it is possible to prevent an increase in pressure loss caused by water passing through those resin elbow fittings 1. Therefore, even if the number of resin elbow fittings 1 in a water supply system increases, it is possible to prevent a decrease in the water flow rate at the water faucet at the end of the water supply system.

[0032] [Second embodiment] Next, a second embodiment of a resin elbow joint will be described with reference to FIGS. As shown in Figure 6, in the resin elbow fitting 1 of this embodiment, the inner circumferential surface of the corner portion 4 of the fitting body 5 is formed by a cylindrical insert 34 made of polyphenylene sulfide resin or the like. Therefore, the inner circumferential surfaces of the inlet portion 4a, outlet portion 4b, and apex portion 4c of the corner portion 4 are located on the inner circumferential surface of this insert 34. The insert 34 is formed by injection molding, and the end of the inner circumferential surface of the insert 34 on the inlet portion 4a side and the end on the outlet portion 4b side are each chamfered.

[0033] The inner peripheral surfaces of the inlet portion 4a, outlet portion 4b, and apex portion 4c of the corner portion 4 are each perfectly circular, and within the corner portion 4, the inner peripheral surface of the inlet portion 4a smoothly connects to the inner peripheral surface of the apex portion 4c, and the inner peripheral surface of the apex portion 4c smoothly connects to the inner peripheral surface of the outlet portion 4b. Furthermore, the inner diameters of the inlet portion 4a and outlet portion 4b are larger than the inner diameter of the apex portion 4c, so that the inner diameter of the corner portion 4 gradually increases from the apex portion 4c to the inlet portion 4a and gradually increases from the apex portion 4c to the outlet portion 4b. This structure of the corner portion 4 ensures that the equivalent pipe length of the plastic elbow fitting 1 is less than 1.0 m, more specifically, less than 0.8 m.

[0034] Next, a method for manufacturing the resin elbow joint 1, more specifically, a method for forming the joint body 5, will be described. FIG. 7 shows a mold 35 for forming the joint body 5 by injection molding. The insert 34 for forming the inner peripheral surface of the corner portion 4 is placed inside the clamped mold 35, along with a pair of pins 36, 37 extending in mutually perpendicular directions. The tips of the pins 36 and 37 are inserted into the insert 34 from their respective ends and butted against each other. A step 36a formed on the outer peripheral surface of the tip of the pin 36 abuts against one end face of the insert 34, i.e., the end face on the inlet 4a side of the corner portion 4. A step 37a formed on the outer peripheral surface of the tip of the pin 37 abuts against the other end face of the insert 34, i.e., the end face on the outlet 4b side of the corner portion 4.

[0035] Thereafter, molten resin is injected into the cavity around the insert 34 and the pins 36, 37 in the mold 35, and the resin is solidified around the insert 34 and the pins 36, 37 to form the joint body 5. More specifically, the first straight portion 2 of the joint body 5 is formed around the pin 36, the corner portion 4 of the joint body 5 is formed around the insert 34, and the second straight portion 3 of the joint body 5 is formed around the pin 37. Then, the pins 36, 37 are pulled out in a direction away from the end face of the insert 34 as the mold 35 is opened.

[0036] In this embodiment, the same effect as that of the first embodiment (1) can be obtained. [Other embodiments] The above-described embodiments can be modified as follows, for example.

[0037] In the first and second embodiments, instead of providing the incore 13 to be inserted into the ends of the pipes 6, 8, an inner cylindrical portion formed integrally with the first straight portion 2 or the second straight portion 3 may be provided inside the housing portion 11 and the seal portion 14 of the first straight portion 2 or the second straight portion 3, and the end of the pipe 6 or the end of the pipe 8 may be inserted onto the outer circumferential surface of the inner cylindrical portion. FIG. 8 shows an example in which an inner cylindrical portion 38 is formed on a resin elbow fitting 1 equipped with an insert 34 as in the second embodiment. In this example, a ring-shaped insertion guide 39 is provided to abut against the ends of the pipes 6, 8 when they are inserted against the outer circumferential surface of the inner cylindrical portion 38 and be pushed together with the ends into the depths between the inner cylindrical portion 38 and the housing portion 11, thereby guiding the insertion of the ends.

[0038] In the first and second embodiments, the first straight portion 2 and the second straight portion 3 of the joint body 5 extend at a right angle, i.e., the inclination angle between the center lines of the first straight portion 2 and the second straight portion 3 is 90°, but this inclination angle does not necessarily have to be 90°. For example, the inclination angle between the center lines may be a value other than 90°, as long as it is within a predetermined range including 90°.

[0039] In the first and second embodiments, the inner diameters of the apex portion 4c, the inlet portion 4a, and the outlet portion 4b of the corner portion 4 of the joint body 5 may be changed as appropriate. For example, the inner diameters of the apex portion 4c, the inlet portion 4a, and the outlet portion 4b may be the same.

[0040] In the first and second embodiments, a polyphenylene sulfide resin mixed with glass fiber is used as the resin forming the joint body 5, but other resins may also be used.

[0041] In the second embodiment, the strength of the insert 34 may be increased by forming ribs on the outer peripheral surface of the insert 34 that extend in the direction along the flow of water inside the resin elbow joint 1.

[0042] In the second embodiment, the strength of the insert 34 may be increased by forming ribs on the inner peripheral surface of the insert 34 that extend in the direction along the flow of water inside the resin elbow joint 1.

[0043] In the second embodiment, the insert 34 may be formed by bending a straight pipe material into an arc shape. In the second embodiment, the insert 34 may be divided into two parts by a plane including the center line of the insert 34. In this case, the insert 34 can be easily formed.

[0044] In the second embodiment, the insert 34 is made of polyphenylene sulfide resin, but it may be made of other resins. Also, the insert 34 may be made of metal instead of resin.

[0045] In the first and second embodiments, the resin elbow joint 1 may be applied to a fluid supply system other than a water supply system, for example, a hot water supply system.

[0046] <Additional Notes> The technical idea that can be grasped from the above embodiment will be described as follows: a resin joint body formed by injection molding and having an L-shaped corner portion integrally formed with a first straight portion and a second straight portion to connect them, a first locking mechanism that prevents the upstream first pipe connected to the first straight portion from coming off, and a second locking mechanism that prevents the downstream second pipe connected to the second straight portion, the joint body is formed to have an equivalent pipe length of less than 1.0 m, the inner peripheral surfaces of the apex portion, inlet portion, and outlet portion of the corner portion are each perfect circles, the inner peripheral surface of the inlet portion and the inner peripheral surface of the apex portion are smoothly connected within the corner portion, and the inner peripheral surface of the apex portion and the inner peripheral surface of the outlet portion are also smoothly connected, a housing portion that houses an end of the first pipe is provided in a portion of the inner peripheral surface of the first straight portion near the corner portion, and the inner peripheral surface of the housing portion and the inner peripheral surface of the inlet portion at the corner portion are smoothly connected a main body block for forming the inner surface of the accommodating portion and the step portion, and a movable block provided at the tip of the main body block for forming the inner surface of the corner portion, wherein each pin can be pulled out from the mold by rotating the movable block relative to the main body block, and a trace of the boundary between the main body block and the movable block is formed at the boundary between each step portion and the corresponding corner portion.

[0047] The joint body is made of resin and is formed by injection molding, and has an L-shaped corner portion that is integrally formed with a first straight portion and a second straight portion to connect them, a first locking mechanism that prevents a first pipe on the upstream side that is connected to the first straight portion from coming off, and a second locking mechanism that prevents a second pipe on the downstream side that is connected to the second straight portion from coming off, wherein an accommodating portion that accommodates an end of the first pipe is provided on an inner peripheral surface of the first straight portion near the corner portion, and an insertion position of the first pipe is provided between the inner peripheral surface of the accommodating portion and an inner peripheral surface of an inlet portion of the corner portion. a step portion is formed to define the insertion position of the second piping, a storage portion is provided on the inner surface of the second straight portion near the corner portion to store the end of the second piping, and a step portion is formed between the inner surface of the storage portion and the inner surface of the outlet portion at the corner portion to define the insertion position of the second piping, and at the boundaries between each step portion and the corresponding corner portion, traces of the parting line of the mold used during injection molding are formed around the entire circumference at each of the boundaries, and the traces on one side and the other side are the same.

[0048] The joint comprises a resin joint body formed by injection molding and having an L-shaped corner portion integrally formed with a first straight portion and a second straight portion to connect them, a first locking mechanism that prevents the first pipe on the upstream side connected to the first straight portion from coming off, and a second locking mechanism that prevents the second pipe on the downstream side connected to the second straight portion from coming off, wherein a receiving portion that receives an end of the first pipe is provided on an inner peripheral surface of the first straight portion near the corner portion, and an insertion position of the first pipe is determined between the inner peripheral surface of the receiving portion and the inner peripheral surface of an inlet portion of the corner portion. a step portion for locating the end of the second piping is formed on the inner circumferential surface of the second straight portion near the corner portion, and a storage portion for accommodating the end of the second piping is provided on the inner circumferential surface of the second straight portion near the corner portion, and a step portion for determining the insertion position of the second piping is formed between the inner circumferential surface of the storage portion and the inner circumferential surface of the outlet portion at the corner portion, and at the protruding corner portions of the step portion that are the boundaries between each step portion and the corresponding corner portion, traces of the parting line of the mold used during injection molding are formed at each of the boundaries, and the traces on one side and the traces on the other side are the same. [Explanation of symbols]

[0049] 1...plastic elbow fitting, 2...first straight section, 3...second straight section, 4...corner section, 4a...inlet section, 4b...outlet section, 4c...vertex section, 5...fitting body, 6...pipe, 7...first locking mechanism, 8...pipe, 9...second locking mechanism, 10...piping cover, 10a...first cover section, 10b...second cover section, 10c...corner cover section, 11...accommodating section, 12...step section, 13...in-core, 13a...flange, 14...seal section, 15...seal ring, 16...spacer, 17 ...Seal ring, 18...Retaining ring, 19...Retaining member, 20...Cap, 21...Insertion ring, 22...Split ring, 23...Lock ring, 24...Mold, 25...Pin, 26...Pin, 27...Main block, 27a...Cylinder, 27b...Coil spring, 28...Movable block, 30...Connecting bar, 31...Support shaft, 32...Slit, 33...Support shaft, 34...Insert, 35...Mold, 36...Pin, 36a...Step portion, 37...Pin, 37a...Step portion, 38...Inner cylinder portion, 39...Insertion guide.

Claims

[Claim 1] A manufacturing device for a resin elbow joint that forms, by injection molding, a resin elbow joint having a resin joint body having an L-shaped corner portion that is integrally formed with a first straight portion and a second straight portion so as to connect the first straight portion and the second straight portion, the resin elbow joint includes a first locking mechanism that prevents a first upstream pipe connected to the first straight section from coming off; a second locking mechanism that prevents a downstream second pipe connected to the second straight portion from coming off; Equipped with an accommodation portion that accommodates an end portion of the first piping is provided in a portion of an inner peripheral surface of the first straight portion near the corner portion, and a step portion that defines an insertion position of the first piping is formed between the inner peripheral surface of the accommodation portion and an inner peripheral surface of an inlet portion of the corner portion; an accommodation portion that accommodates an end portion of the second piping is provided in a portion of an inner circumferential surface of the second straight portion near the corner portion, and a step portion that defines an insertion position of the second piping is formed between the inner circumferential surface of the accommodation portion and an inner circumferential surface of an outlet portion at the corner portion; a pair of pins for molding the inner circumferential surfaces of the accommodation portions, the step portions, and the corner portions are arranged in the injection molding die, and each of the pins is removable from the die; In each of the pins, a portion forming an inner peripheral surface of the accommodating portion, the step portion, and the inner peripheral surface of the corner portion is divided into two parts so that a trace of a parting line is formed at a protruding corner portion of the step portion that is a boundary between each of the step portions and the corresponding corner portion, When each pin is pulled out of the mold, the pins are not forcibly pulled out from the corner portion due to the division into two parts, and conversely, if it is assumed that each pin is not divided, each pin would be forcibly pulled out from the corner portion.

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