JP7485534B2 - Fittings - Google Patents

Description

The present invention relates to a joint that connects a vertical pipe and a horizontal pipe.

Conventionally, a joint for connecting a vertical pipe and a horizontal pipe, such as that described in Patent Document 1 below, has been known.
The joint described in Patent Document 1 consists of an L-shaped curved pipe having an upper connection port and a lower connection port, and is supported by being suspended below the concrete slab by a suspension bolt.
In this joint, a support protrusion is provided at the lower end of the bent part of the curved pipe, and this support protrusion is placed on a support plate suspended from a concrete slab via a vibration isolating member. In the case of a joint connecting a vertical pipe and a horizontal pipe, the joint is subjected to the impact of wastewater falling through the vertical pipe, so the above-mentioned structure provides a support structure that can absorb impacts and vibrations.

JP 2004-270219 A

Among these types of joints, the leg joint is located at the bottom of the drainage water flowing down, and is generally made of materials with impact resistance such as cast iron, or resins with high impact resistance, to withstand the impact of drainage water or falling objects. In particular, the inner bottom surface of the leg joint is considered to be an area that requires impact resistance, since it is directly hit by drainage water or falling objects.
As the resin material for increasing the impact strength, vinyl chloride resin obtained by craft copolymerization with acrylic rubber or mixed therewith can be used.

By the way, this type of joint may be constructed as an integrally molded product from resin. To integrally mold a joint from resin, a mold is used and molten resin is injected into a molding cavity formed in the mold to obtain a molded product.
When producing this molded product, molten resin is injected into the mold cavity from the gate, so a fused resin part called a weld line is generated where the molten resin that branches along the mold cavity joins together. Also, because the gate of the mold is the part where the molten resin is injected, a gate mark is generated in the part of the molded product that corresponds to the gate.

In the joint connecting the above-mentioned vertical pipe and horizontal pipe, there is a risk of impact from a falling object at the section from the vertical pipe to the curved pipe, and if a weld line or gate mark is present in this section, depending on the condition of the weld line or gate mark, this may have an adverse effect on the durability of the joint.
Furthermore, when considering a joint as an injection molded product, unless the resin filling balance is uniform, there are problems such as distortion occurring in some areas, reducing impact strength and rigidity.

In view of the above, the present invention aims to provide a fitting made of a molded resin body, with a weld line, that does not cause durability problems even when subjected to an impact caused by an object falling from a standpipe.

In order to solve the above problems, the present invention proposes the following aspects.
"1" The fitting of this embodiment is a fitting consisting of a resin molded body including a first receiving portion into which a standpipe is placed, a second receiving portion into which a horizontal pipe is attached, and a curved pipe portion connecting the first receiving portion and the second receiving portion, and is characterized in that, in a planar view of the first receiving portion seen from the outside along its axial direction, a portion of the curved pipe portion onto which an opening of the curved pipe portion on the first receiving portion side is projected is a projected portion, and in a state in which the second receiving portion side of the projected portion with respect to the central axis of the first receiving portion in the planar view is a pressure-receiving portion, a weld line is not formed in the pressure-receiving portion but is formed in a portion other than the pressure-receiving portion, and in a side view of the first receiving portion, the second receiving portion, and the curved pipe portion are seen from a direction perpendicular to both the central axis of the first receiving portion and the central axis of the second receiving portion, a gate mark is not formed in the pressure-receiving portion but is formed on the opposite side to the pressure-receiving portion side with respect to the central axis of the first receiving portion.

When wastewater or objects from the standpipe fall from the first receiving port into the curved pipe, a large impact is mainly applied to the pressure-receiving portion at the projection below the opening of the first receiving port. Therefore, if there are gate marks or weld lines in this pressure-receiving portion, repeated impacts may cause problems with the durability of the gate marks and weld lines over time.
In the joint of this embodiment, there are no gate marks or weld lines in the pressure-receiving portion, and the gate marks and weld lines are formed in the portion other than the pressure-receiving portion. As a result, the gate marks and weld lines are provided in positions that are less susceptible to impact from a falling object, so it is possible to provide a joint that does not have problems with durability even when it is subjected to impact from a falling object.

"2" In the joint according to this embodiment, a configuration can be adopted in which the gate mark is formed above the central axis of the second receiving portion.

When a gate mark is provided on the side opposite the pressure-receiving portion with respect to the central axis of the first receiving portion and above the central axis of the second receiving portion, a weld line is formed on the upper back side of the curved pipe portion or in an area close to the upper back side. The upper back side of the curved pipe portion is located away from the bottom side of the curved pipe portion that will be impacted by a falling object, so a joint with sufficiently enhanced impact resistance against a falling object can be provided.

"3" The joint according to this embodiment is a joint consisting of a resin molded body including a first receiving portion into which a vertical pipe is placed, a second receiving portion into which a horizontal pipe is attached, and a curved pipe portion connecting the first receiving portion and the second receiving portion, and in a planar view of the first receiving portion seen from the outside along its axial direction, the portion of the curved pipe portion onto which the opening of the first receiving portion side of the curved pipe portion is projected is a projected portion, and in the projected portion, the side of the second receiving portion relative to the central axis of the first receiving portion in the planar view is a pressure-receiving portion. In the above, the weld line is not formed in the pressure-receiving portion but is formed in a portion other than the pressure-receiving portion, and is located at the boundary of the second receiving portion side of the projected portion in a side view of the first receiving portion, the second receiving portion, and the curved pipe portion in a direction perpendicular to both the central axis of the first receiving portion and the central axis of the second receiving portion, and when a partition line parallel to the central axis of the first receiving portion is defined, a gate mark is not formed in the pressure-receiving portion but is formed in the area between the central axis of the first receiving portion and the partition line.

In this embodiment of the joint, there are no gate marks or weld lines in the pressure-receiving portion, but the gate marks and weld lines are formed in the area between the central axis and the partition line of the first receiving port portion, i.e., in the portion other than the pressure-receiving portion, on the side of the curved pipe portion. As a result, the gate marks and weld lines are located in a position that is unlikely to be subjected to impact from a falling object, so a joint can be provided that does not have durability problems even when subjected to impact from a falling object.

"4" In the joint of this embodiment, a configuration can be adopted in which the gate mark is not formed in the pressure-receiving portion, but is formed in the area between the central axis of the first receiving port portion and the partition line, above the pressure-receiving portion.

If the gate mark is formed in the region between the central axis of the first receiving portion and the dividing line, above the pressure-receiving portion, i.e., on the side of the curved pipe portion, a weld line is formed on the opposite side of the curved pipe portion, but this position corresponds to the portion excluding the pressure-receiving portion. Therefore, since the weld line is provided in an area away from the bottom side of the curved pipe portion that will be impacted by a falling object, even if a falling object collides with the inner bottom surface of the curved pipe portion, there is little impact on the weld line portion. This makes it possible to provide a fitting with sufficiently improved impact resistance.

“5” In the joint according to this embodiment, a configuration can be adopted in which the gate mark is formed above the central axis of the second receiving portion.

The joint of this embodiment has a gate mark on the side of the curved pipe section, and the weld line that occurs in the curved pipe section during molding can be formed on the other side of the curved pipe section. As a result, the weld line can be provided in a position that is unlikely to be subjected to impact from a falling object, and the gate mark is also in a position that is not directly subjected to impact, so a joint can be provided that does not cause durability problems even if it is subjected to impact from a falling object.

"6" The fitting of this embodiment is a fitting consisting of a resin molded body having a first receiving portion into which a vertical pipe is placed, a second receiving portion into which a horizontal pipe is attached, and a curved pipe portion connecting the first receiving portion and the second receiving portion, and in a planar view of the first receiving portion seen from the outside along its axial direction, a projected portion is a portion of the curved pipe portion onto which an opening of the curved pipe portion on the first receiving portion side is projected, and of the projected portion, a projection portion is a portion of the curved pipe portion onto which an opening of the curved pipe portion on the first receiving portion side is projected relative to the central axis of the first receiving portion in the planar view. When the receiving port side is the pressure receiving portion, a weld line is not formed in the pressure receiving portion but is formed in a portion other than the pressure receiving portion, and when the boundary of the projected portion on the second receiving port side is displayed with a division line in a side view of the first receiving port portion, the second receiving port portion, and the curved pipe portion viewed from a direction perpendicular to both the central axis of the first receiving port portion and the central axis of the second receiving port portion, a gate mark is not formed in the pressure receiving portion but is formed on the second receiving port side of the division line.

If the gate mark is formed on the second receiving port side of the dividing line, excluding the pressure-receiving portion, the weld line can be provided in a position that is less likely to be impacted by a falling object, providing a joint that does not have durability problems even if it is impacted by a falling object.

"7" In the joint of this embodiment, a configuration can be adopted in which the gate mark is formed in the region between the partition line and the second receiving portion in the side view state, in the lower region of the region obtained by vertically dividing the region above the central axis of the second receiving portion into two equal parts, and in the region below the central axis of the second receiving portion.

When gate marks are formed in the area between the dividing line and the second receiving portion, in the area below the two equal areas above the central axis of the second receiving portion and in the area below the central axis, a weld line is formed on the upper back side of the curved pipe portion, so that the weld line can be provided in a position that is less susceptible to impact from falling objects, providing a joint that does not have durability problems even when subjected to impact from falling objects.

"8" The joint according to this embodiment can adopt a configuration in which the weld line is formed on the upper back side of the curved pipe section.

Because the weld line is formed on the upper back side of the bent pipe section, it can be placed in a position that is less susceptible to impact from falling objects, providing a joint that does not pose durability problems even if it is subjected to impact from a falling object.

"9" In the joint according to this embodiment, a configuration can be adopted in which the weld line described in "8" is formed so as to continue to the upper surface side of the first receiving portion that is continuous with the upper part of the back surface of the curved pipe portion, and to the upper surface side of the second receiving portion that is continuous with the upper part of the back surface of the curved pipe portion.

The weld line is formed on the upper back side of the bent pipe section, as well as on the top side of the first and second receiving ports. However, since the weld line is located in a position that is unlikely to be subjected to impact from a falling object, a joint can be provided that does not pose a problem in durability even if subjected to impact from a falling object.

"10" In the joint according to this embodiment, a first pipe section is formed between the first receiving portion and the curved pipe section, a second pipe section is formed between the curved pipe section and the second receiving portion, and the second pipe section is formed longer than the first pipe section, and a horizontal section is formed on the inner bottom surface side of the second pipe section.

The first pipe section is shorter than the second pipe section, so that the fitting and the second pipe section can be positioned to fit snugly in a narrow vertical space. In addition, because the first pipe section is short and the second pipe section is long, splashing inside the curved pipe section is suppressed, allowing the wastewater to flow smoothly. If splashing occurs inside the curved pipe section, the wastewater will splash and jump, causing the wastewater to flow unsmoothly.

"11" In the joint according to this embodiment, a configuration can be adopted in which a support leg is formed on the underside of the bottom of the curved pipe section and protrudes downward.

Having support legs allows the joint to be installed stably when it is installed at the installation site or on the floor.

"12" In the joint according to this embodiment, a configuration can be adopted in which the lower end surface of the support leg is formed flush with the lower surface of the horizontal pipe.

By forming the bottom end surface of the support leg and the bottom end surface of the horizontal pipe in a flush position, when the joint is installed on site or on the floor, the bottom end of the support leg and the bottom end of the horizontal pipe can be installed horizontally and stably on the horizontal surface or floor of the site.

"13" In the joint according to this embodiment, a configuration in which a reinforcing rib is formed on the outer periphery of the support leg can be adopted.

The presence of reinforcing ribs increases the strength of the support legs and improves the stability of the structure supporting the joint.

With this type of joint, there are no gate marks or weld lines in the pressure-receiving portion, and the gate marks and weld lines are formed in portions other than the pressure-receiving portion. As a result, the gate marks and weld lines are located in positions that are less susceptible to impact from falling objects, providing a joint that does not have durability problems even when subjected to impact from a falling object.

FIG. 1 is a cross-sectional view along the vertical direction of a drainage system equipped with a joint of a first embodiment according to the present invention, showing a vertical pipe and a horizontal pipe from the side. FIG. 2 is a side view of the joint shown in FIG. 1 . 2. FIG. 4 is a side view of the joint shown in FIG. 1, seen from the opposite side to FIG. FIG. 2 is a longitudinal sectional view of the joint shown in FIG. 1 . FIG. 2 is a front view of the joint and the bent pipe portion shown in FIG. 1 as viewed from the outer periphery side of the bent pipe portion. FIG. 2 is a plan view of the joint shown in FIG. 1 . FIG. 2 is a rear view of the joint shown in FIG. 1 . FIG. 2 is a side view showing an example of a suspended state in the joint shown in FIG. 1 . 2 is an explanatory diagram showing an example of an initial state in which resin is injected from a gate provided at a first position when molding the joint shown in FIG. 1 . FIG. 2 is an explanatory diagram showing an example of a state in which resin is injected halfway through a gate provided at a first position when molding the joint shown in FIG. 1 . FIG. FIG. 11 is an explanatory diagram showing residual stresses in a joint manufactured by the resin injection procedure shown in FIGS. 9 and 10 . 1. FIG. 4 is an explanatory view showing another example of the initial state in which resin is injected from a gate provided at a second position when molding the joint shown in FIG. 1. FIG. 4 is an explanatory diagram showing another example of a state in which resin is injected halfway through a gate provided at a second position when molding the joint shown in FIG. FIG. 14 is an explanatory diagram showing residual stresses in a joint manufactured by the resin injection procedure shown in FIGS. 12 and 13 . 1. FIG. 4 is a side view showing another example in which a cleaning window is provided in a curved pipe portion of the joint shown in FIG. FIG. 16 is a rear view of the joint shown in FIG. FIG. 16 is a side view showing an example of a suspended state in the modified joint shown in FIG. 15 . FIG. 18 is a rear view of the joint shown in FIG. 17 . FIG. 2 is a side view showing a first example in which a plurality of weld lines are provided in the joint shown in FIG. FIG. 20 is a rear view of the joint shown in FIG. 19 . FIG. 2 is a side view showing a second example in which a plurality of weld lines are provided in the joint shown in FIG. FIG. 22 is a rear view of the joint shown in FIG. 21 . FIG. 2 is a side view showing a third example in which a plurality of weld lines are provided in the joint shown in FIG. 1 . FIG. 24 is a rear view of the joint shown in FIG. 23 . FIG. 2 is a side view showing a fourth example in which a plurality of weld lines are provided in the joint shown in FIG. FIG. 26 is a rear view of the joint shown in FIG. 25 . FIG. 11 is a side view showing an example of a case where multiple weld lines are provided in a joint whose gate position is outside the range of the present invention. FIG. 28 is a rear view of the joint shown in FIG. 27. FIG. 13 is a side view showing an example in which a plurality of weld lines are provided in a joint in which the weld line is outside the scope of the present invention. FIG. 30 is a rear view of the joint shown in FIG. 29 .

Hereinafter, an example of a case in which a joint according to an embodiment of the present invention is applied to a drainage system will be described with reference to Figs. 1 to 6.
As shown in Fig. 1, the drainage system 10 of this embodiment is an example applied to a multi-story building (building) such as a high-rise apartment building, a commercial building, etc. In this type of building, wastewater discharged from sanitary equipment (drainage equipment) such as toilets, vanities, and sinks on each floor flows into a vertical main pipe 20 of a drainage channel through a horizontal branch pipe (not shown).
The vertical main pipe 20 is provided so as to pass through each floor (floor slab S). The wastewater flows down along the vertical main pipe 20 to the lowest floor of the multi-story building, flows into the horizontal pipe 30 via a joint (leg joint) 50 connected to the lower end of the vertical main pipe 20, and is finally sent to the sewer main pipe, a septic tank, etc. The drainage system 10 discharges the wastewater from the drainage equipment on each floor to the outside of the building.

The drainage system 10 comprises a vertical main pipe 20, a horizontal pipe (horizontal main pipe) 30, and a joint structure 40.
The vertical main pipe 20 collects and guides the drainage water from the drainage equipment installed on each floor downward. The vertical main pipe 20 includes a plurality of collective joints 21 provided corresponding to each floor, and a first pipe (not shown) that connects the collective joints 21 provided on adjacent floors in the vertical direction.
As shown in FIG. 1, of the multiple joints 21, the joint 21 for the lowest floor provided on the lowest floor of the building is provided with a branch pipe connection portion 22 and a standpipe 23 for penetrating the slab.

The branch pipe connection part 22 is located above the floor slab S. A horizontal branch pipe (not shown) is connected to the branch pipe connection part 22. The horizontal branch pipe guides the wastewater discharged from the drainage equipment to the branch pipe connection part 22. A part or all of the branch pipe connection part 22 may be transparent. In this case, the wastewater flowing from the horizontal branch pipe into the branch pipe connection part 22 can be seen from the outside.

The standpipe 23 for penetrating the slab extends downward from the branch pipe connection part 22. The standpipe 23 is formed in a cylindrical shape extending in the vertical direction. The standpipe 23 penetrates the floor slab S in the vertical direction. The lower end of the standpipe 23 protrudes downward from the floor slab S. The nominal diameter of the standpipe 23 is, for example, about 75 to 125.

A through hole 8 is formed in the floor slab S in the vertical direction, a standpipe 23 is provided to pass through this through hole 8, and a filler material 9 made of glass wool (GW) or rock wool (RW) is filled in the gap between the through hole S and the standpipe 23. The filler material 9 may be other filler materials such as mortar.

In this embodiment, the standpipe 23 may have thermal expansion properties. In this case, even if a fire breaks out on one of the multiple floors, the standpipe 23 expands, blocking the inside of the standpipe 20. This prevents the flames from reaching the floors above and below the floor where the fire breaks out through the inside of the standpipe 20. The standpipe 23 is, for example, tubular and made of metal such as cast iron or resin such as polyvinyl chloride. In the case of resin, the standpipe 23 may be made of a multi-layer pipe. In this case, a configuration including an inner layer and an outer layer made of polyvinyl chloride resin and an intermediate layer containing polyvinyl chloride resin and thermally expandable graphite can be adopted.

The horizontal pipe 30 guides the wastewater that has flowed through the vertical main pipe 20 horizontally and discharges it outside the site.
1 , the horizontal main pipe 30 includes a second pipe 31 and a cleaning joint 32. The second pipe 31 is connected to a joint structure 40. The nominal diameter of the second pipe 31 (horizontal main pipe 30) may be, for example, about 100 to 150. The nominal diameter of the horizontal pipe 30 may be larger than the nominal diameter of the vertical main pipe 20.
The cleaning joint 32 is disposed on the opposite side of the joint structure 40 with the second pipe 31 in between. The cleaning joint 32 is formed with a cleaning port 33. A lid 34 is detachably attached to the cleaning port 33. Note that a part or the whole of the cleaning joint 32 may be transparent. In this case, the wastewater flowing from the second pipe 31 into the cleaning joint 32 can be easily visually observed from the outside.

As shown in FIG. 1 , the joint (leg joint) 50 connects the riser pipe 23 and the horizontal pipe 30 .
The joint 50 comprises a first annular receiving portion 51 into which the vertical pipe 23 is placed, a second annular receiving portion 52 into which the horizontal pipe 30 is attached, and a curved pipe portion 53 which is L-shaped in side view and connects the first receiving portion 51 and the second receiving portion 52.
The first receiving portion 51 is a receiving port into which the standpipe 23 is inserted. The lower end of the standpipe 23 is attached to the first receiving portion 51. The second receiving portion 52 is a receiving port into which the horizontal pipe 30 is attached. The end of the second piping 31 is fitted into the second receiving portion 52.
For example, the outer circumferential surface of the second pipe 31 is bonded to the inner circumferential surface of the second receiving portion 52 .

As shown in FIG. 1, the second receiving portion 52 is shifted in one direction D of the horizontal direction with respect to the first receiving portion 51. Hereinafter, the direction in which the second receiving portion 52 is located with respect to the first receiving portion 51 along the one direction D may be referred to as the first direction side D1, and the opposite side of the first direction side D1 may be referred to as the second direction side D2. When the central axis of the first receiving portion 51 (hereinafter referred to as the first central axis O1) is arranged parallel to the vertical direction, the central axis of the second receiving portion 52 (hereinafter referred to as the second central axis O2) has a drainage gradient that is downward as it approaches the first direction side D1. The first central axis O1 and the second central axis O2 intersect with each other. The distance L1 from the upper edge of the first receiving portion 51 to the intersection X of the two central axes O1 and O2 may be 200 mm or less.

The curved pipe section 53 includes a first pipe section 54 extending from the first receiving portion 51 in the direction of the central axis of the first receiving portion 51 (downward), a second pipe section 55 extending from the second receiving portion 52 in the direction of the central axis of the second receiving portion 52, and an L-shaped connecting section 56 connecting the first pipe section 54 and the second pipe section 55.
The first pipe portion 54 has a smaller diameter than the first socket portion 51. The first socket portion 51 and the first pipe portion 54 are connected via a first step portion 57. In the embodiment shown in FIG. 1, the second pipe portion 55 is formed to be longer than the first pipe portion 54.

The bent pipe portion 56 connects the first pipe portion 54 and the second pipe portion 55 over the entire circumference except for the portion where the two are directly connected as described above. A cylindrical support leg 59 that protrudes downward is formed on the lower surface side of the bottom of the bent pipe portion 56.
2 and subsequent figures, four reinforcing ribs 59a are formed around the periphery of the support leg 59 at 90° intervals. These reinforcing ribs 59a extend upward from a position slightly above the lower end of the support leg 59, and are made of triangular plates that gradually become thicker as they extend upward, and are each integrated with the support leg 59. The distance from the lower end of the support leg 59 to the bottom surface of the curved pipe portion 53 varies depending on the circumferential position of the support leg 59, so the four reinforcing ribs 59a formed around the periphery of the support leg 59 are formed to lengths appropriate to the respective formation positions.

The support legs 59 are supported by, for example, support fittings not shown in FIG.
In this embodiment, the support leg 59 protrudes downward at a position where the central axis O1 of the first receiving portion 51 passes through the outer circumferential bottom of the curved pipe portion 56. A lower end surface 59b is formed at the lower end of the support leg 59, which becomes a horizontal plane when the joint 50 is attached as shown in Fig. 1. Since this lower end surface 59b is formed at the same height as the lower end of the second receiving portion 52 as shown in Fig. 1, the joint 50 can be installed alone horizontally on an installation surface such as a floor.

The joint 50 is made of a molded body of resin such as polyvinyl chloride, and is preferably made of a resin having excellent impact resistance.
Examples of resins with excellent impact resistance include vinyl chloride resins, such as (1) resins obtained by mixing polyvinyl chloride polymers with impact-modified resins, (2) resins obtained by graft-copolymerizing polyvinyl chloride polymers with impact-modified resins, (3) copolymers of vinyl chloride monomers with monomers having unsaturated bonds copolymerizable with the vinyl chloride monomers, and (4) graft copolymers obtained by graft-copolymerizing vinyl chloride with (co)polymers other than vinyl chloride. These (1) to (4) may be used alone, or two or more of them may be used in combination. Furthermore, the polyvinyl chloride resins may be chlorinated as necessary.

Examples of the impact-improving resin to be mixed with the polyvinyl chloride polymer in (1) above, and the impact-improving resin to be graft-copolymerized with the polyvinyl chloride polymer in (2) above, include resins having rubber properties. Specific examples include acrylonitrile-butadiene-styrene copolymer, methyl methacrylate-butadiene-styrene copolymer, acrylic rubber, chlorinated polyethylene, ethylene-vinyl acetate copolymer resin, and acrylonitrile-butadiene copolymer. These may be used alone, or two or more types may be used in combination.

By using a polyvinyl chloride resin in which the above-mentioned resin having rubber properties is mixed or graft-copolymerized, the impact resistance of the polyvinyl chloride resin can be improved.
The joint 50 is subject to a risk of damage because it is directly hit by wastewater and other falling objects falling from the standpipe 20. It is preferable to form the joint 50 from a resin having excellent impact resistance in order to prevent damage to the joint 50 caused by the impact of the wastewater.

A part or the whole of the joint 50 may be transparent. In this case, the wastewater flowing from the standpipe 20 into the joint 50 can be visually observed from the outside.
In addition, it is preferable that the nominal diameter (inner diameter, outer diameter) of the first receiving portion 51 is larger than the nominal diameter (inner diameter, outer diameter) of the horizontal pipe 30 (second piping 31). In this case, even if the standpipe 20 (standpipe 23) with the largest nominal diameter is installed in the first receiving portion 51, the drainage capacity of the horizontal pipe 30 can be ensured to be equal to or greater than the drainage capacity of the standpipe 20. As a result, the drainage capacity of the entire drainage system 10 can be maintained.

As described above, the joint 50 is made of a molded resin body, but in order to further improve the impact resistance of the joint 50, it is necessary to carefully consider the gate position of the mold for molding the joint 50 and the positions of the gate marks and weld lines formed on the molded product, that is, the joint 50, in accordance with this gate position.
As a basic rule for specifying the location of the gate marks and weld lines, first, it is necessary that the gate marks and weld lines are not provided in areas where falling objects or wastewater falling through the standpipe 23 could collide with the fitting 50 and cause a large impact.

Next, in the case of a cylindrical joint 50 as in this embodiment, when resin is injected from a gate into the molding cavity of a mold, the resin flows around to the opposite side of the resin injection position when viewed in cross section of the molding cavity, and a weld line is generated on this opposite side. Therefore, it is necessary that the weld line generated as described above does not exist in the area where a falling object or wastewater collides with the joint 50 and causes a large impact.

In this specification, since the stand pipe 23 is connected to the first receiving portion 51 and the horizontal pipe 30 is connected to the second receiving portion 52 as shown in Fig. 1, when the joint 50 is installed in an L-shape as viewed from the side, the outer circumferential side of the curved pipe portion 56 can be referred to as the front side of the joint 50, and the top side of the curved pipe portion 56 where the first receiving portion 51 and the second receiving portion 52 are closest to each other can be referred to as the upper back side of the joint 50. Similarly, when the joint 50 is viewed from the back side to the front side, the surfaces present on the left and right of the curved pipe portion 56 can be referred to as the side surfaces of the joint 50.
When the joint 50 is viewed from above as shown in Fig. 6, that is, when the first receiving portion 51 is viewed from above (outside) along its central axis, the portion of the curved pipe portion 53 onto which the opening 51a on the first receiving portion side of the curved pipe portion 53 is projected is referred to as projected portion B. Projected portion B is a portion visible inside the opening 51a in the plan view of Fig. 6, and can be represented as the region indicated by the symbol B when viewed in cross section as shown in Fig. 4.

Falling objects and wastewater that fall through the standpipe 23 mainly first collide with this projected portion B. However, if the portion located on the second receiving portion side with respect to the central axis O1 of the first receiving portion 51 in a plan view is defined as the pressure-receiving portion B1, it is considered that the impact on this pressure-receiving portion B1 is the largest. In addition, in the projected portion B, the portion other than the pressure-receiving portion B1, for example, the portion to the left of the central axis O1 in Figures 4 and 6, has an inner surface of the curved pipe portion 53 at a large inclination angle with respect to the horizontal plane, so that the impact that this portion receives from falling objects and wastewater is considered to be smaller than that on the pressure-receiving portion B1.
Based on the above interpretation, in this embodiment, it is considered that a configuration in which neither gate marks nor weld lines are provided in the pressure-receiving portion B1 is essential for providing a joint 50 with excellent impact resistance.

The pressure-receiving portion B1 is an area to the right of the first central axis O1 (the second socket portion side) in the side view of the joint 50 shown in Fig. 2 and in the cross-sectional view of the joint shown in Fig. 4, and the position of the right end of the pressure-receiving portion B1 is the position of the left end of the second straight pipe 55. The side view of the joint 50 can be referred to as the state when the joint 50 is viewed along a direction perpendicular to both the central axis O1 of the first socket portion 51 and the central axis O2 of the second socket portion 52. In the side view, the bottom side of the second pipe portion 55 is a horizontal portion.
In order to clearly indicate the boundaries of these regions, a dividing line L1 is set that passes through a position including the right end of the projection portion B or the right end of the pressure-receiving portion B1 and is parallel to the first central axis O1, as shown in Figures 2 and 4.

Next, when the curved pipe section 56, the first pipe section 54, and the second pipe section 55 are viewed from the side as shown in Figure 2, we will consider the state in which gate marks and weld lines are formed in each of the areas divided by the first central axis O1, the dividing line L1, and the second central axis O2.
2 and 4, in the joint 50, the region to the left of the first central axis O1 and below the first receiving portion 51 is set as region E. In the joint 50, the region between the first central axis O1 and the demarcation line L1 and below the first receiving portion 51 is set as region F. Next, the region from the demarcation line L1 to the second receiving portion 52, which is mainly composed of the second straight pipe 55, is set as region G.

Gate marks may be provided over the entire region E. When gate marks are provided in region E, a more preferable region is a region above the upper end of the uppermost reinforcing rib 59a among the multiple reinforcing ribs 59a provided around the support leg 59, and more preferably a region above the second central axis O2.
Furthermore, a more preferable upper limit of the region in the case where a gate mark is provided in region E is up to the region directly below the first receiving portion 51 in the vicinity of the first central axis O1 in the side view of Fig. 2, and up to the lower end position of the first straight pipe 54 on the side away from the first central axis O1 in the direction perpendicular to the first central axis O1. The vicinity of the first central axis O1 is a side away from the first central axis O1 in the direction perpendicular to the first central axis O1 by about 1/5 or more of the inner diameter of the first pipe portion 54 in the side view of Fig. 2.
A more preferable range in the case where a gate mark is provided in region E is shown as a shaded region in Fig. 2. As an example of a gate mark provided in this region, gate mark 56b provided on the upper outer periphery of bent pipe portion 53 is shown.

In the region F, a gate mark may be formed on the upper side of the region F excluding the pressure-receiving portion B1. As an example of a gate mark formed in this region, a gate mark 56a formed in the center of the side surface of the curved pipe portion 53 is shown.
However, if a gate mark is formed on the upper side of region F near the dividing line L1, a weld line may be formed in the pressure-receiving portion B1, so it is undesirable for a gate mark to be formed on the upper side of region F near the dividing line L1.
For this reason, in the region F, which is obtained by dividing the region above the second central axis O2 into two equal parts vertically, it is preferable not to provide a gate mark in the region near the dividing line L1.
In view of this, a desirable area in region F where the gate mark is provided is above the second central axis O2 and toward the center of the side surface of the curved pipe portion 53.

The central side of the side surface of the curved pipe portion 53, represented by the central portion of the region F, is a region outside the projected portion B described above.
Furthermore, when a gate mark 56a is formed in the center of the side surface as shown in FIG. 2, a gate is formed in the die for molding the joint 50 at a position corresponding to this gate mark.
When molten resin is injected from the gate at this position to mold fitting 50, as shown in the test results described below, the molten resin flows from the side of fitting 50 shown in FIG. 2 to the opposite side (the side shown in FIG. 3), and the molten resins join together in the center of the side shown in FIG. 3, resulting in the formation of weld line WL1 at the position shown by the dashed line in FIG. 3.

This weld line WL1 does not exist in projected portion B of joint 50, and is formed on the side surface of joint 50 opposite to the side surface on which gate mark 56a exists. In addition, as shown in Figure 3, this weld line WL1 is formed so as to pass from the center of the side surface of first receiving portion 51, pass through the center of the side surface of curved pipe portion 53, pass through the center of the side surface of second receiving portion 52, and reach the end of second receiving portion 52 when fitting 50 is viewed from the side.
In the joint 50 of this embodiment, neither the gate mark 56a nor the weld line WL1 exists in the pressure-receiving portion B1, so that the impact resistance of the joint 50 can be improved.

It should be noted that the position where the weld line WL1 shown in Fig. 3 is just one example, and the position where the weld line is generated is not limited to the position shown in Fig. 3. The weld line WL1 shown in Fig. 3 is an example of a case where the gate is arranged to correspond to the center position of the side surface of the curved pipe portion 53 shown in Fig. 2 and the molten resin flows ideally.
If the gate is positioned at a position other than that shown in Figure 2 or at a position other than the center within the central area of the side, the weld line WL1 will be formed at a position slightly shifted in the vertical or horizontal direction from the position of the weld line WL1 shown in Figure 3. In either case, however, as long as the weld line WL1 is not formed in an area close to the pressure-receiving portion B1, this will contribute to improving the impact resistance of the fitting 50.

In region G, it is preferable that gate marks are formed in the lower region obtained by dividing the region above the second central axis O2 into two equal parts vertically, and in the lower side of region G below the second central axis O2. However, even if the region G is below the second central axis O2, it is more preferable to exclude the region close to the pressure-receiving portion B1 and the region close to the second receiving mouth portion 52.
In the region G, if the gate mark is formed in the upper region of the region obtained by vertically dividing the region above the second central axis O2 into two equal parts, a weld line may be formed in the pressure-receiving portion B1. If the gate mark is formed in the region G below the second central axis O2 and close to the pressure-receiving portion B1, there is a concern about the influence of impacts caused by falling objects or wastewater.
For this reason, in the region G in side view, when the region above the second central axis O2 is divided into two equal parts vertically, the lower side of the lower region is a more preferable position for forming the gate mark. Also, in the region G below the second central axis O2, when the region is divided into thirds in the left-right direction in side view, the central region of the thirds is a more preferable position for forming the gate mark.
FIG. 2 shows an example of a gate mark 56c formed at the bottom of the central region divided into three equal parts.

In the embodiment described so far based on Figures 2 to 7, a gate mark 56a is formed, preferably in the center, on one side of the joint 50, and a weld line WL1 is formed on the other side, but the positions of the gate mark and the weld line in this embodiment of the joint are not limited to the above example.

When the gate mark 56b is formed below the first receiving mouth portion 51 and on the upper outer periphery side of the curved pipe portion 53 as shown in Figure 2, the weld line WL2 is formed on the upper back side of the curved pipe 53 as shown by the dashed lines in Figures 2, 6, and 7.

When the gate mark 56b is formed in region E and the weld line WL2 is formed on the upper back side of the curved pipe section 53, even if an object or wastewater falling from the vertical pipe 23 collides with the bottom side of the curved pipe 53, the impact on the gate mark 56b and the weld line WL2 is minimal, so a joint 50 with excellent impact resistance can be provided.

The position where the weld line WL2 is generated as shown in Figures 2, 6, and 7 is just one example, and the position where the weld line is generated is not limited to the position shown in these figures. The weld line WL2 shown in Figures 2, 6, and 7 is an example of the case where the gate is positioned to correspond to the center of the curved pipe portion 53 shown in Figure 2, and the molten resin flows ideally.
If the gate is positioned above or below or to the left or right of the position shown in Figure 2, a weld line will be formed at a position slightly shifted left or right or up or down from the position of the weld line WL2 shown in Figures 2, 6, and 7. However, as long as the weld line WL2 is not formed in the pressure-receiving portion B1, this will contribute to improving the impact resistance of the fitting 50.

When the gate mark 56c is formed in the lower part of the region G, the weld line WL3 is formed on the upper side of the back surface of the curved pipe 53 as shown by the dashed lines in FIGS.
When the gate mark 56c is formed in the lower part of the region G and the weld line WL3 is formed on the upper side of the back surface of the curved pipe section 53, even if an object or wastewater falling from the vertical pipe 23 collides with the bottom side of the curved pipe 53, the impact on the part where the gate mark 56c is formed and the part where the weld line WL3 is formed is small, so that a fitting 50 with excellent impact resistance can be provided.

The first receiving portion 51 or the second receiving portion 52 may be considered as a location where the gate mark is formed. However, if injection molding is performed with a gate provided at a position corresponding to the first receiving portion 51 or the second receiving portion 52, this can cause problems with filling the molten resin, and the molded product is likely to have a defective shape. For this reason, fittings in which the gate mark is formed at the first receiving portion 51 or the second receiving portion 52 are not preferred.

In the joint 50 shown in Figures 1 to 7, the first pipe section 54 is formed shorter than the second pipe section 55, so that the joint 50 and the second pipe section 55 can be positioned below the floor slab S to fit comfortably in a narrow space in the vertical direction.
In addition, by making the first pipe section 54 short and the second pipe section 55 long, the generation of splashes on the inner bottom surface side of the curved pipe section 53 is suppressed, and as a result, the wastewater can flow smoothly. If splashes are generated on the inner bottom surface side of the curved pipe section 53, the wastewater will splash and jump, and the flow of the wastewater will become unsmooth.

FIG. 8 shows an example of a structure in which the support legs 59 of the joint 50 are supported by metal fittings.
In the example shown in Figure 8, a support plate 61 made of an L-shaped steel material or an L-shaped resin plate is supported horizontally by a pair of left and right hanging bolts 60 suspended from a floor slab S. A leg joint 62 is provided in a support hole formed in the center of this support plate 61, and the tip of the support leg 59 is supported by a boss provided in this leg joint 62.

According to the structure shown in FIG. 8, the support legs 59 of the joint 50 can be supported by the floor slab S via the hanging bolts 60, so that the joint 50 can be stably supported.
Furthermore, even if the joint 50 receives a large impact from a falling object, the support structure shown in FIG. 8 can provide a joint structure that can withstand the impact.

"Analysis example"
Simulation analysis was performed using analysis software (MoldFlow Insight 2018) manufactured by AUTODESK Corporation on the case where the joints having the shapes shown in Figures 2 to 7 are integrally molded by injection molding. The mold temperature was set to 25°C, the polyvinyl chloride resin (PVC resin) temperature to 200°C, and the injection time to 40 s (50 cm3/s). As shown in Figure 9, the resin flow was analyzed when the PVC resin was injection molded from a gate with a diameter of 16 mm on the upper side of the outer circumferential surface of the curved pipe portion and approximately 7 cm below the first receiving port portion.

FIG. 9 shows the flow state of the resin 5.919 seconds after the start of injection, FIG. 10 shows the flow state of the resin 24.07 seconds after the start of injection, and FIG. 11 shows an example of the stress analysis results of a joint obtained after injection molding.
As shown in the analysis results shown in Figures 9 and 10, when the gate is positioned on the upper side of the outer circumferential surface of the curved pipe portion, i.e., corresponding to region E shown in Figure 2, it was confirmed that a weld line is formed on the upper side of the back surface of the curved pipe portion.

Under the same analytical conditions as above, we analyzed the flow of resin when PVC resin was injection molded from a gate with a diameter of 16 mm, located approximately 8 cm below the first receiving port on the central side of the curved pipe section, as shown in Figure 12.

FIG. 12 shows the flow state of the resin 5.920 seconds after the start of injection, FIG. 13 shows the flow state of the resin 24.08 seconds after the start of injection, and FIG. 14 shows an example of the stress analysis results of a joint obtained after injection molding.
As shown in the analysis results shown in Figures 12 and 13, when the gate is positioned to correspond to the center of the side of the curved pipe portion, i.e., the center of region F shown in Figure 2 (the center of the side of the curved pipe portion), it was confirmed that a weld line is formed on the side of the curved pipe portion.

In the stress analysis results shown in FIG. 11 and FIG. 14, the areas colored in gray indicate areas in the molded product where the highest residual stress has accumulated.
When comparing the analysis results of the stress state shown in Figure 11 with the analysis results of the stress state shown in Figure 14, it was found that the analysis result shown in Figure 11 shows that the residual stress is uniformly distributed around the outer periphery of the second receiving mouth portion 52, whereas the analysis result shown in Figure 14 shows that the residual stress is non-uniformly distributed around the outer periphery of the second receiving mouth portion 52.

Although there is no direct problem with the joint because the distribution of residual stress is non-uniform, in terms of the variation in residual stress, it is believed that the joint with the structure shown in Figure 11 is more preferable. It is believed that when the variation in residual stress is small, the accumulation of strain due to thermal history is smaller than when the variation is large.
For this reason, it can be presumed that the most desirable location for providing the gate is when the gate mark is formed in region E shown in Figures 2 and 5, and that in this case it is possible to provide a joint that is least susceptible to the accumulation of distortion.

Although an embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes configuration changes, combinations, additions, deletions, etc. within the scope of the gist of the present invention.

15 and 16 show another example in which a cleaning port 70 is provided in the curved pipe portion 53 of the joint 50. In the example shown in FIG.
As shown in Figures 15 and 16, a cleaning port 70 may be provided in the curved pipe section 53 of the joint 50. In the illustrated example, the cleaning port 70 is provided on both sides of the curved pipe section 53, but it may be provided on only one side. This allows inspection and cleaning of the joint 50. The cleaning port shown in Figures 15 and 16 may be provided with a lid body 71 that can be attached to the cleaning port 70 of the joint 50. An engagement groove 72 may be provided in the lid body 71. This allows the lid body 71 to be easily opened and closed by engaging a rod-shaped tool such as the shaft of a screwdriver, i.e., a general-purpose tool, with the engagement groove 72.
15 and 16 , the cleaning port 70 is shifted toward the first direction side D1 with respect to the support leg 59. Therefore, as described above, when the lid body 71 is removed using a general-purpose tool, the hanging bolt 60 is unlikely to interfere with the general-purpose tool.

In contrast, in Figs. 17 and 18, the cleaning port 70 and the lid 71 are located on the second direction side D2 compared to the joint 50 shown in Fig. 16. As a result, the cleaning port 70 and the lid 71 overlap the hanging bolt 60 with the lid 71 in one direction D. In such a case, the metal fittings provided on the support leg 59 and the general-purpose tool engaged with the engagement groove 72 may interfere with each other, making it difficult to attach and remove the lid 71. In other words, it is preferable that the cleaning port 70 does not overlap the support leg 59 in the direction of the central axis O1 when the joint 50 is viewed from the side, as in the example shown in Figs. 15 and 16, rather than as in the modified example shown in Figs. 17 and 18.

For example, in the above embodiment, there is only one gate, but multiple gates may be provided.

19 to 26 show examples in which a plurality of gate marks are provided in the joint 50. That is, these are examples in which gates are provided at a plurality of locations.
19 and 20 , the gate mark 56b and another gate mark 56c are provided as the gate marks. The gate mark 56c is provided on the upper part of the second receiving portion 52. In this case, the weld line WL4 is provided in a portion other than the projected portion B, and is provided in the bent portion 53 so as to gradually move from the top to the bottom toward the first direction side D1 in a side view.
21 and 22 , the gate mark 56b and another gate mark 56d are provided as the gate marks. The gate mark 56d is provided in the lower part of the second receiving portion 52. In this case, the weld line WL5 is provided in a part other than the projected part B, in the bent part 53, so as to gradually move from the top to the bottom toward the second direction side D2 in a side view.
As shown in Figures 23 to 26, in addition to the first gate 56b or 56c, a second gate 56f may be provided in the upper part of the second tube section 55 (a location 180° opposite the region F with respect to the tube axis of the second tube section 55 as the center). In the example shown in Figures 23 and 24, the second gate 56f is provided in addition to the first gate 56b. In the example shown in Figures 25 and 26, the second gate 56f is provided in addition to the first gate 56c.
In this case, two weld lines are formed on the side of the joint 50, specifically, a second weld line WL6 is formed on the opposite side of the first weld line WL1 in Fig. 3. The weld lines WL1 and WL6 are provided at positions equidistant from the gate marks 56b, 56c, and 56f.
23 to 26, since the weld lines WL1 and WL6 can be positioned so as to be equidistant from all gates, it is preferable to set the gate marks 56b, 56c, and 56f so that a line connecting points equidistant from the gate marks 56b, 56c, and 56f does not pass through the pressure-receiving portion B1. This makes it possible to prevent the mold structure from becoming complicated.

27 and 28, in a joint 50A according to a comparative example, gate marks 56g, 56h are provided in the pressure-receiving portion B1. The gate marks 56g, 56h are provided in portions of the pressure-receiving portion B1 that face each other with the joint 50 in between. As a result, a plurality of weld lines WL11, WL12 are provided in the joint 50. Note that one of these weld lines WL11 crosses the pressure-receiving portion B1 in one direction D.
In the case of the structures shown in Figures 27 and 28, if the joint 50 receives a large impact from a falling object, there is a risk that the joint may be damaged.

29 and 30, in a joint 50A according to another comparative example, a gate mark 56i is provided at the end of the first receiving port 51 on the second direction side D2, and a gate mark 56j is provided at the lower part of the second receiving port portion 52. As a result, a weld line WL13 crosses the pressure-receiving portion B1 in the circumferential direction of the joint 50A.
In the case of the structures shown in Figures 29 and 30, if the joint 50 receives a large impact from a falling object, there is a risk that the joint may be damaged.

10...Drainage system, 20...Standby main pipe, 21...Collecting joint, 22...Branch pipe connection section, 23...Standby pipe, 30...Horizontal pipe, 40...Joint structure, 50...Joint, 51...First receiving port section, 52...Second receiving port section, 53...Bent pipe section, 54...First pipe section, 55...Second pipe section, 56...Connection section,
56a, 56b, 56c...gate marks, 59...support legs, 59a...reinforcement ribs, 59b...lower end surfaces,
B: Projection portion; B1: Pressure receiving portion;
S...floor slab, WL1, WL2...weld line, O1, O2...center axis,
E, F, G...areas, L1...dividing line.

Claims (8)

A joint made of a resin molded body including a first receiving portion into which a standpipe is disposed, a second receiving portion into which a horizontal pipe is attached, and a curved pipe portion connecting the first receiving portion and the second receiving portion,
In a planar view of the first receiving portion seen from the outside along the axial direction, a portion of the curved pipe portion onto which an opening of the curved pipe portion on the first receiving portion side is projected is defined as a projected portion, and in the planar view, a portion of the projected portion on the second receiving portion side with respect to a central axis of the first receiving portion is defined as a pressure-receiving portion.
A weld line is not formed in the pressure-receiving portion but is formed in a portion other than the pressure-receiving portion,
When the first receiving portion, the second receiving portion, and the curved pipe portion are viewed from a side in a direction perpendicular to both a central axis of the first receiving portion and a central axis of the second receiving portion, a gate mark is not formed in the pressure-receiving portion but is formed on the opposite side to the pressure-receiving portion with respect to the central axis of the first receiving portion ,
A joint characterized in that the gate mark is formed above the central axis of the second receiving portion . A joint made of a resin molded body including a first receiving portion into which a standpipe is disposed, a second receiving portion into which a horizontal pipe is attached, and a curved pipe portion connecting the first receiving portion and the second receiving portion,
In a planar view of the first receiving portion seen from the outside along the axial direction, a portion of the curved pipe portion onto which an opening of the curved pipe portion on the first receiving portion side is projected is defined as a projected portion, and in the planar view, a portion of the projected portion on the second receiving portion side with respect to a central axis of the first receiving portion is defined as a pressure-receiving portion.
A weld line is not formed in the pressure-receiving portion but is formed in a portion other than the pressure-receiving portion,
When the first receiving portion, the second receiving portion, and the curved pipe portion are viewed from a side in a direction perpendicular to both the central axis of the first receiving portion and the central axis of the second receiving portion, a partition line is defined that is located at the boundary of the projected portion on the second receiving portion side and is parallel to the central axis of the first receiving portion,
A gate mark is not formed in the pressure-receiving portion but is formed on the second receiving portion side from the dividing line ,
A joint characterized in that the gate mark is formed in the region between the partition line and the second receiving portion when viewed from the side, in the lower region of the region obtained by dividing the region above the central axis of the second receiving portion into two equal parts vertically, and in the region below the central axis of the second receiving portion . A joint made of a resin molded body including a first receiving portion into which a standpipe is disposed, a second receiving portion into which a horizontal pipe is attached, and a curved pipe portion connecting the first receiving portion and the second receiving portion,
In a planar view of the first receiving portion seen from the outside along the axial direction, a portion of the curved pipe portion onto which an opening of the curved pipe portion on the first receiving portion side is projected is defined as a projected portion, and in the planar view, a portion of the projected portion on the second receiving portion side with respect to a central axis of the first receiving portion is defined as a pressure-receiving portion.
A weld line is not formed in the pressure-receiving portion but is formed in a portion other than the pressure-receiving portion,
When the first receiving portion, the second receiving portion, and the curved pipe portion are viewed from a side in a direction perpendicular to both a central axis of the first receiving portion and a central axis of the second receiving portion, a gate mark is not formed in the pressure-receiving portion but is formed on the opposite side to the pressure-receiving portion with respect to the central axis of the first receiving portion ,
A joint characterized in that the weld line is formed on the upper surface side of the curved pipe portion, on the side where the first receiving portion and the second receiving portion are adjacent to each other . A joint as described in claim 3, characterized in that the weld line is formed so as to continue from the upper surface side of the first receiving portion that continues to the upper side of the back surface of the curved pipe portion to the upper surface side of the second receiving portion that continues to the upper side of the back surface of the curved pipe portion. A joint as described in any one of claims 1 to 4, characterized in that a first pipe portion is formed between the first receiving portion and the curved pipe portion, a second pipe portion is formed between the curved pipe portion and the second receiving portion, the second pipe portion is formed longer than the first pipe portion, and a horizontal portion is formed on the inner bottom surface side of the second pipe portion. A joint according to any one of claims 1 to 5 , characterized in that a support leg protruding downward is formed on the underside of the bottom of the bent pipe portion. A joint according to claim 6 , characterized in that the lower end surfaces of the support legs are formed flush with the lower surface of the horizontal pipe. 8. The joint according to claim 6 , wherein a reinforcing rib is formed on an outer periphery of the support leg.

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