JP2001021089A - Branch connection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a branch connection which enables drainage to smoothly flow through a branching part. SOLUTION: A tubular connection body 51 is inserted in a connection port 37 of a riser pipe 32 of a public loge 30. This connection body 51 has a curved flange part 56 in the outer peripheral side of an end part located inside of the riser pipe 32. A spacer body 53 is fitted on the outer peripheral side of the connection body 51 at the end part thereof which is located outside of the riser pipe 32, and a nut body 54 is fastened and engaged to the space body 63. In this engaged condition, the peripheral edge part of the connection port 37 and the spacer body 53 are located between the nut body 54 and the curved flange part 56 so that the connection body 51 which holds at its inner peripheral surface a branch pipe 41 fitted thereby is fixed in the connection port 37. The inner peripheral surface of this connection body 51 is formed as a cylindrical surface having a uniform diameter and having an inner diameter with which the downstream end part of the branch pipe 41 can be loosely fitted in the connection body 51, extending from the axially one end to the other end thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a branch joint for connecting a branch connection pipe to a connection port formed in a side face of a connection pipe and opening the connection port.

[0002]

2. Description of the Related Art Conventionally, as this type of branch joint, for example, a branch joint described in Japanese Patent Application Laid-Open No. Hei 5-33382 is known.

As shown in FIG. 8, for example, this conventional branch joint has a connection port 2 formed in a side surface of a pipe 1 to be connected.
And a tubular joint body 3 inserted through the joint body 3.
A curved flange portion 4 having a curved shape corresponding to the inner peripheral surface of the connected pipe 1 is formed on the outer peripheral side of the end located inside the connected pipe 1.

On the inner peripheral side of the end of the joint body 3 located inside the connected pipe 1, a locking step 7 capable of locking the downstream end of the branched connecting pipe 6 is formed. The locking step 7 projects toward the inner periphery with substantially the same size as the thickness of the branch connection pipe 6.

[0005] On the outer peripheral side of the joint body 3, a spacer body having one side surface facing the outer peripheral surface of the connected pipe 1 formed by a curved surface 8 corresponding to the outer peripheral surface of the connected pipe 1. 9 and an engaging fixed body 10 such as a nut body.
Is engaged, the peripheral portion of the connection port 2 of the pipe 1 to be connected and the spacer body 9 are sandwiched between the engagement fixing body 10 and the curved flange portion 4, and the joint body 3 is connected to the connection pipe 1. 1 is fixed to the connection port 2.

[0006]

However, in the above-described conventional branch joint, for example, when the position of the upstream end of the branch connection pipe 6 is determined, the downstream end of the branch connection pipe 6 is connected to the joint body 3. Is located in front of the locking step 7 and the concave portion 11 is formed at the branch portion.
In addition to the risk of clogging, there is a problem that the flow of drainage at the branch portion is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a branch joint capable of eliminating a concave portion at a branch portion and improving drainage flow at the branch portion.

[0008]

According to a first aspect of the present invention, there is provided a branch joint which is inserted into a connection opening formed in a side surface of a connected pipe, and is provided on an outer peripheral side of an end located inside the connected pipe. An inner peripheral surface having a curved flange portion having a curved shape corresponding to the inner peripheral surface of the connection pipe, the inner peripheral surface for fitting and holding the downstream end of the branch connection pipe extends from one end to the other end of the branch connection pipe downstream of the branch connection pipe. A tubular joint main body formed into an equi-diameter cylindrical surface with an inner diameter that allows an end to be freely inserted, and one side surface attached to the outer peripheral side of the joint main body and facing the outer peripheral surface of the connected pipe; Is disposed between the spacer body formed of a curved surface corresponding to the outer peripheral surface of the connected pipe and an outer peripheral side of the joint body, and is engaged with the curved flange portion in an engaged state. A state in which the peripheral portion of the connection port of the connected pipe and the spacer body are sandwiched. In which the joint body was provided with the engagement fixing member for fixing to the connecting port Te.

The inner peripheral surface of the joint main body is formed in an equi-diameter cylindrical shape from the one end to the other end in the axial direction with an inner diameter dimension that allows the downstream end of the branch connection pipe to be loosely inserted. The drainage from the branch connecting pipe flows smoothly toward the connected pipe without forming a concave portion on the inner peripheral surface of the pipe.

[0010] In the branch joint according to a second aspect of the present invention, in the branch joint according to the first aspect, the joint main body is inserted into the connection port of the connected pipe from the inside of the connected pipe, and is located inside the connected pipe. One end in the axial direction has a curved flange portion on the outer peripheral side, and the inner peripheral surface is formed into an equi-diameter cylindrical surface with an inner diameter dimension that allows the downstream end of the branch connection pipe to be freely inserted from one end to the other end in the axial direction And the branch connection pipe is fitted and connected to the outer peripheral side of the other end in the axial direction of the tubular base member, and the inner peripheral surface exposed inward extends from one end to the other end in the axial direction. Is formed by a flexible tubular member which is formed in an equi-diameter cylindrical shape with an inner diameter dimension allowing play and continuous with the inner peripheral surface of the tubular base member.

The downstream end of the branch connection pipe is fitted on the inner peripheral surface of the flexible tubular member which is fitted and connected to the outer peripheral side of the other end of the tubular base member of the joint body. When held, the branch connection pipe becomes swingable, and the earthquake resistance is improved.

According to a third aspect of the present invention, there is provided a branch joint according to the second aspect, further comprising a tightening band for bringing the inner peripheral surface of the flexible tubular member into close contact with the outer peripheral surface of the branch connection pipe in a tightened state. is there.

[0013] Then, the tightening band makes the inner peripheral surface of the flexible tubular member and the outer peripheral surface of the branch connecting pipe closely contact each other in the tightened state, so that the fitting and holding state of the branch connecting pipe by the flexible tubular member is ensured. Is maintained.

According to a fourth aspect of the present invention, there is provided the branch joint according to the second or third aspect, wherein the flexible tubular member of the joint body has a plurality of annular concave grooves formed in the axially intermediate outer peripheral surface. It is formed in.

Since a plurality of annular grooves are formed in the axial direction on the outer circumferential surface of the flexible tubular member in the middle in the axial direction, the flexible tubular member bends while ensuring strength. It will be easier.

A branch joint according to a fifth aspect of the present invention is the branch joint according to any one of the second to fourth aspects, wherein the tubular base member of the joint main body has a downstream end portion of the branch connection pipe located below the end face in the axial direction. The supporting projection is formed so as to project from below.

Since the support projection of the tubular base member supports the downstream end of the branch connection pipe from below, the downstream end of the branch connection pipe may sink under the influence of the load from above. Is prevented.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a branch joint according to an embodiment of the present invention;

FIG. 3 is a front view showing an example of construction of a branch joint. In FIG. 3, reference numeral 21 denotes a road such as asphalt, and a side groove 22 is provided on one side of the road 21.
22 is located at the border of residential land 23 which is private land.

Under the road 21, there is a sewer main
25 is buried deep underground, and the downstream end of the inclined mounting pipe 26 is connected to the side of the sewer main pipe 25.
A pipe joint 27 is connected to the upstream end of the pipe, and a public box 30 as a box is connected to the pipe joint 27.

The public square 30 has a bent pipe 31 opened upward and downward, and a rising pipe 32 as a cylindrical connected pipe which is connected upright to the upper opening of the bent pipe 31. It is composed of

The bent tube 31 is formed of a synthetic resin such as a vinyl chloride resin into a tubular shape, and is bent at an intermediate position in the axial direction, for example, about 75 degrees in accordance with the inclination of the mounting tube 26. . The lower opening of the bent pipe 31 is a spigot, and is fitted and connected to the pipe joint 27. This bent tube 31
In the vicinity of the upper surface opening, an enlarged diameter portion 33 as a receiving portion is formed, and the lower end portion of the rising pipe 32 is fitted and connected to the enlarged diameter portion 33.

The riser tube 32 is formed of a synthetic resin such as a vinyl chloride resin into a cylindrical shape, and an upper opening opening upward is closed by a cover 35 so as to be openable and closable. The upper surface of the lid 35 is located on the same plane as the ground surface of the residential land 23.

Further, on the side surface of the rising pipe 32,
At an intermediate position in the axial direction, that is, in the vertical direction, a substantially circular connection port 37 opened in a direction away from the road 21 is formed, and a branch joint 40 is attached to the connection port 37. The downstream end of the branch connection pipe 41 for drainage is connected to 40. The upstream end of the cylindrical branch connection pipe 41 is connected to a box 43 located at the downstream end of the outdoor drainage facility 42 buried in the residential land 23.

Here, as shown in FIGS. 1 and 2, the branch joint 40 has a tubular joint body 51 inserted through a connection port 37 of the riser pipe 32. An annular packing body 52 made of elastic rubber or the like is fitted on the outer peripheral side of a portion located inside the inner portion 32, and an annular outer peripheral portion of a portion of the joint body 51 located outside the riser tube 32 is provided. A spacer body 53 is fitted, and a nut body 54 as an annular engagement fixing body is engaged with the spacer body 53 by pressing.

When the nut body 54 is in a tightened engagement state, a connection port between the packing body 52 and the rising pipe 32 is provided between the nut body 54 and the curved flange portion 56 of the joint body 51. 37 and the spacer body 53 is sandwiched, and in this state, the joint body 51
Is fixed to the connection port 37, and the fixed joint body is
The downstream end of the branch connection pipe 41 is fitted and held on the inner peripheral surface on the distal end side of the pipe 51.

The joint main body 51 has a tubular base member 61 inserted into the connection port 37 of the riser tube 32 from the inside of the riser tube 32, and one end portion on the outer peripheral side of the end of the tubular base member 61. And a flexible tubular member 62 fitted and connected.

The tubular base member 61 is formed of a synthetic resin such as a vinyl chloride resin or the like. One end in the axial direction is located inside the inner surface of the riser tube 32. The curved flange portion 56 is formed on the outer peripheral surface of the located one end portion so as to protrude toward the outer peripheral direction. The curved flange portion 56 is formed in a curved shape corresponding to the inner peripheral surface of the riser tube 32, and the outer surface of the curved flange portion 56 contacts the inner peripheral surface of the riser tube 32 via the packing body 52. In contact.

A thread groove 65 as an engaged portion is formed on the outer peripheral surface of the tubular base member 61 at an intermediate position in the axial direction. The nut body 54 is screwed into the thread groove 65 and tightened. In the engaged state. Further, the other end of the tubular base member 61 in the axial direction is formed by a fitting portion 66, and a thin and annular engaging projection 67 is formed on the end face of the fitting portion 66 so as to protrude. The inner diameter of the engaging projection 67 is larger than the inner diameter of the fitting part 66.

On the other hand, the inner peripheral surface of the tubular base member 61 extends from one end to the other end in the axial direction, and the branch connection pipe 41 extends from one end to the other end.
Is formed in an equi-diameter cylindrical surface shape with an inner diameter dimension that allows the downstream end portion to be loosely inserted. That is, the inner diameter of the tubular base member 61 is slightly larger than the outer diameter of the branch connection pipe 41.

The flexible tubular member 62 is formed into a substantially cylindrical shape with elastic rubber or the like, and one end in the axial direction is expanded at the fitted portion 71 into which the fitting portion 66 is fitted. Formed into a diameter,
On the inner end side of the inner peripheral surface of the fitted portion 71, an annular engagement receiving step portion 72 with which the engaging projection 67 is engaged is formed, and on the outer peripheral surface of the fitted portion 71, One annular concave groove 73 is formed.
The fitting portion 66 of the tubular base member 61 is fitted and connected to the fitted portion 71 of the flexible tubular member 62, and the engaging projection 67 is engaged with the engagement receiving step 72. ing. A band 75 having a width corresponding to the annular groove 73 is fitted into the first annular groove 73 of the flexible tubular member 62. The joint portions 66 are firmly connected and fixed in a state of being in close contact with each other. The engagement between the engagement projection 67 and the engagement receiving step 72 increases the contact area between the tubular base member 61 and the flexible tubular member 62, and the fitting portion 66 and the fitted portion 71 Is securely fitted.

A plurality of, for example, three annular grooves 76 are formed at equal intervals in the axial direction on the outer peripheral surface of the flexible tubular member 62 at the intermediate position in the axial direction. A second annular concave groove 77 is formed on the outer peripheral surface of.

Further, the inner peripheral surface of the portion of the flexible tubular member 62 other than the fitted portion 71, that is, the inner peripheral surface exposed inward in the state of being fitted to the tubular base member 61 is An inner diameter dimension in which the downstream end of the branch connection pipe 41 can be freely inserted from one end to the other end in the axial direction, that is, the tubular base member.
It is formed in the shape of a cylinder having the same diameter as the inner diameter of 61, and is continuous with the inner peripheral surface of the tubular base member 61.

Then, the downstream end of the branch connection pipe 41 is inserted into the inner peripheral surface of the flexible tubular member 62, and a tightening band 78 is fitted into the second annular groove 77, and the tightening band 78 is inserted. The band 78 is tightened so that the inner peripheral surface of the flexible tubular member 62 and the outer peripheral surface of the branch connection pipe 41 are in close contact with each other.

On the other hand, the spacer body 53 is formed of a synthetic resin such as a vinyl chloride resin or a synthetic rubber material, and one side of the side facing the outer peripheral surface of the riser tube 32 is formed of the riser tube 32. A curved surface 53a corresponding to the outer peripheral surface is formed, and the entire curved surface 53a contacts the outer peripheral surface of the riser tube 32.

The other side surface of the spacer body 53 is formed in a planar shape, and this planar surface is in contact with one planar side surface of the nut body 54. On the outer peripheral portion of the nut body 54, a plurality of handle portions 54a are formed at intervals in the circumferential direction so that the nut body 54 can be strongly tightened.

Next, the mounting operation of the above embodiment will be described.

In attaching the branch joint 40 to the connection port 37 of the riser pipe 32 of the public basin 30, first, the tubular base member 61 of the joint body 51 in which the packing body 52 is fitted is attached to the open upper surface of the riser pipe 32. It is inserted into the riser tube 32 from the opening.

Then, the tubular base member 61 is connected to the rising pipe 32.
And the curved flange portion 56 of the tubular base member 61 is brought into contact with the inner peripheral surface of the riser tube 32 via the packing body 52.

Next, on the outer peripheral side of the tubular base member 61 inserted through the connection port 37, a spacer body 53 is attached to the curved surface 53.
a is fitted to the riser tube 32, and then the nut body 54 is screwed into the thread groove 65.

Then, the nut body 54 is rotated and tightened using the handle 54a of the nut body 54, so that the packing body 52, between the nut body 54 and the curved flange portion 56, is tightened. Connection port 37 of the riser pipe 32
And the spacer body 53 is sandwiched, and the tubular base member 61 of the joint body 51 is fixed to the connection port 37.

Next, the fitted portion 71 of the flexible tubular member 62 is fitted and connected to the fitted portion 66 of the fixed tubular base member 61,
A band 75 is fitted into the first annular concave groove 73 of the fitted portion 71, and the band 75 is temporarily fixed. Further, a fastening band 78 is fitted into the second annular concave groove 77 of the flexible tubular member 62 and temporarily fixed thereto.

On the other hand, the branch connecting pipe 41 is connected to the public square 30 and the residential land 23.
A predetermined length according to the separation distance from the square 43 in the inside, that is,
The upstream end of the branch connection pipe 41 is locked to a not-shown locking step of the connection port 43a of the box 43, and the downstream end of the branch connection pipe 41 is exposed inward of the flexible tubular member 62. And cut to a length that can be fitted and held on the inner peripheral surface.

Then, the branch connection pipe 41 cut to a predetermined length is inserted into and removed from the inner peripheral side of the joint main body 51 fixed to the connection port 37, and the branch connection pipe 41 is removed.
Position the downstream end of 41.

That is, as shown by the two-dot chain line in FIG.
After once inserting the downstream end of the branch connecting pipe 41 to the inside of the riser pipe 32 of the public basin 30 and pulling it out in the direction of the arrow, the upstream end of the branch connecting pipe 41 is It is fitted and connected in an appropriate state to the connection port 43a of the box 43 embedded and fixed therein, and is locked by the locking step of the connection port 43a.

Then, with the upstream end of the branch connection pipe 41 being locked by the locking step of the connection port 43a, the downstream end of the branch connection pipe 41 is set as shown in FIG. Is inevitably positioned at a position separated from the end face of the fitting portion 66 of the tubular base member 61.

After this positioning, the fastening band 78 temporarily fixed in advance is tightened so that the outer peripheral surface of the branch connection pipe 41 and the inner peripheral surface of the flexible tubular member 62 are brought into close contact with each other. The downstream end of the branch connection pipe 41 is fitted and held on the inner peripheral surface of the member 62.

Further, the band 75 temporarily fixed in advance is also tightened, and the fitting portion 66 of the tubular base member 61 and the flexible tubular member 62 are tightened.
The parts 71 to be fitted are tightly connected to each other and firmly connected and fixed.

As described above, according to the above-described embodiment, the inner peripheral surface exposed inward of the joint main body 51 extends from one end to the other end in the axial direction at the downstream end of the branch connection pipe 41. Is formed into an equi-diameter cylindrical surface with an inner diameter that allows easy insertion,
The downstream end of the branch connection pipe 41 can be taken in and out of the joint body 51.

Therefore, even when the positions of both ends of the branch connection pipe 41 are determined, the upstream end of the branch connection pipe 41 can be properly locked to the locking step of the connection port 43a of the box 43. In addition, the downstream end of the branch connection pipe 41 can be appropriately fitted and held on the inner peripheral surface of the flexible tubular member 62. Therefore, unlike the related art, a concave portion is not formed on the inner peripheral surface of the branch portion, the flow of drainage at the branch portion can be improved, and the dirt 12 and the like are not clogged in the branch portion as in the related art.

Further, since the downstream end of the branch connection pipe 41 is fitted and held by the inner peripheral surface exposed inward in the fitted state of the flexible tubular member 62 and the tubular base member 61, the earthquake is prevented. When the flexible tubular member 62 is elastically deformed, the branch connecting pipe is
Since the 41 swings about the lower end, damage to the joint body 51 can be prevented, and the earthquake resistance can be improved.

Further, the tightening band 78 on the outer peripheral side of the flexible tubular member 62 of the joint body 51 makes the inner peripheral surface of the flexible tubular member 62 and the outer peripheral surface of the branch connection pipe 41 closely contact each other. The fitting and holding state of the branch connection pipe 41 by the flexible tubular member 62 can be reliably maintained.

Further, a plurality of annular concave grooves 76 are formed in the axially intermediate outer peripheral surface of the flexible tubular member 62 of the joint body 51 in the axial direction. Member 62
Can be easily bent, and the seismic resistance can be further improved. Further, since the concave grooves 76 are formed at equal intervals in the axial direction, the flexible tubular member 62 can be smoothly bent by the uniform dispersion of stress. Can be.

Further, by using the tubular base member 61 and the flexible tubular member 62, not only a concave portion cannot be formed at the branch portion, but also the tolerance of the length of the branch connection pipe 41 can be increased, and the mounting operation can be performed. Performance can be improved.

In the above embodiment, the joint main body 51 is formed of a tubular base member 61 and a flexible tubular member 62 which are separate members, and these tubular base member 61 and the flexible tubular member are formed. Although the configuration in which 62 is connected and fixed by the band 75 has been described, for example, the tubular base member 61 and the flexible tubular member 62 can be integrally formed.

Further, the joint body 51 in the above embodiment is used.
As shown in FIG. 4 to FIG. 7, a support protrusion 80 that abuts on the lower outer peripheral surface of the downstream end of the branch connection pipe 41 and supports from below is provided below the axial end surface of the tubular base member 61. A configuration in which the projection is formed can also be adopted.

As shown in FIG. 7, the support projection 80
The branch connection pipe is projected from the lower part of the outer end face of the fitting part 66.
41 is formed in a curved shape and a plate shape corresponding to the outer peripheral surface. That is, as shown in FIG. 6, the support protrusion 80 is formed in an arc shape centered on a point О which is a point on the central axis of the tubular base member 61, and the arc angle α shown in FIG. Degrees. Further, a step portion 81 is formed along the circumferential direction at a tip edge portion of the support protrusion 80.

The flexible tubular member 62 of the joint body 51
Is located at the lower part on the inner end side of the inner peripheral surface of the fitted portion 71 having an enlarged diameter,
A protrusion fitting portion 82 having a shape corresponding to the support protrusion 80 is formed by cutting out in a U-shape, and the support protrusion 80 is fitted into the protrusion fitting portion 82. Further, the outer peripheral surface of the flexible tubular member 62 in the middle in the axial direction does not have the concave groove portion 76,
It is formed in a cylindrical shape.

According to the branch joint 40 having the structure shown in FIGS. 4 and 7, in addition to the functions and effects of the above-described embodiment, the upper surface of the support projecting portion 80 of the tubular base member 61 has a branch connection pipe.
Abutting against the lower outer peripheral surface of the downstream end of
Supports the downstream end of the branch connecting pipe 41 from below, so that the downstream end of the branch connecting pipe 41 can be prevented from sinking due to the adverse effect of an overhead load such as earth pressure.

[0060]

According to the first aspect of the present invention, the inner peripheral surface of the joint main body extends from one end to the other end in the axial direction, and has an inner diameter dimension such that the downstream end of the branch connection pipe can be freely inserted. Since it is formed in a planar shape, it is possible to eliminate the concave portion at the branch portion and improve the flow of drainage at the branch portion.

According to the second aspect of the present invention, the inner peripheral surface of the flexible tubular member which is fitted and connected to the outer peripheral side of the other end of the tubular base member of the joint main body is branched and connected at the inner surface. When the downstream end portion of the pipe is fitted and held, the branch connection pipe is in a swingable state, and it is possible to improve the earthquake resistance.

According to the third aspect of the present invention, the tightening band makes the inner peripheral surface of the flexible tubular member and the outer peripheral surface of the branch connection pipe come into close contact with each other in the tightened state. The fitting and holding state of the tube can be reliably maintained.

According to the fourth aspect of the present invention, since a plurality of annular concave grooves are formed in the axial direction on the axially intermediate outer peripheral surface of the flexible tubular member, the flexibility is ensured while ensuring strength. The tubular member can be easily bent, and the earthquake resistance can be further improved.

According to the fifth aspect of the present invention, since the supporting projection of the tubular base member supports the downstream end of the branch connecting pipe from below, the support connecting section of the branch connecting pipe is affected by the load from above. It is possible to prevent the downstream end from sinking.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a branch joint of the present invention.

FIG. 2 is a transverse sectional view showing the branch joint according to the first embodiment;

FIG. 3 is a front view showing one construction example of the above branch joint.

FIG. 4 is a longitudinal sectional view showing another embodiment of the branch joint of the present invention.

FIG. 5 is a transverse sectional view showing the branch joint.

FIG. 6 is a front view showing a joint main body of the branch joint;

FIG. 7 is a partially cutaway perspective view showing a joint main body of the branch joint;

FIG. 8 is a longitudinal sectional view showing a conventional branch joint.

[Explanation of symbols]

 32 Rise pipe as connected pipe 37 Connection port 40 Branch joint 41 Branch connection pipe 51 Joint body 53 Spacer body 53a Curved surface 54 Nut body as engagement fixing body 56 Curved flange 61 Tubular base member 62 Flexible tubular member 76 Concave groove 78 Tightening band 80 Support protrusion

Claims (5)

[Claims] 1. A connection port formed in a side face of a connected pipe and having a curved shape corresponding to an inner peripheral surface of the connected pipe on an outer peripheral side of an end located inside the connected pipe. An inner diameter surface having a curved flange portion and having an inner diameter dimension allowing the downstream end portion of the branch connection tube to be freely inserted from one end to the other end in the axial direction for fitting and holding the downstream end portion of the branch connection tube; A tubular joint body formed in a planar shape; and a curved surface attached to the outer peripheral side of the joint body, the one side of the side facing the outer peripheral surface of the connected pipe corresponding to the outer peripheral surface of the connected pipe. And a spacer body formed so as to be engageable with an outer peripheral side of the joint body, and a peripheral portion of a connection port of the connected pipe and the spacer between the curved flange portion in an engaged state. A member for fixing the joint body to the connection port in a state where the body is sandwiched. Branch connection, characterized by comprising a fixed body. 2. The joint body is inserted into the connection port of the connected pipe from inside the connected pipe,
An inner diameter having a curved flange portion on the outer peripheral side of one end in the axial direction located inside the connected pipe, and an inner peripheral surface capable of loosely inserting the downstream end of the branch connecting pipe from one end to the other end in the axial direction. A tubular base member formed in the shape of a cylindrical surface with an equal diameter, and an inner peripheral surface that is fitted and connected to the outer peripheral side of the other end portion in the axial direction of the tubular base member, and has an inner peripheral surface that is exposed inward and has one end in the axial direction. And a flexible tubular member formed to be continuous with the inner peripheral surface of the tubular base member in an equi-diameter cylindrical shape with an inside diameter dimension allowing the downstream end of the branch connection pipe to be freely inserted from the other end to the other end. The branch joint according to claim 1, wherein the joint is formed. 3. The branch joint according to claim 2, further comprising a tightening band for bringing the inner peripheral surface of the flexible tubular member into close contact with the outer peripheral surface of the branch connection pipe in a tightened state. 4. The branch according to claim 2, wherein the flexible tubular member of the joint body has a plurality of annular concave grooves formed in the axial direction on an intermediate outer peripheral surface in the axial direction. Fittings. 5. The tubular base member of the joint main body is formed with a support protrusion for supporting a downstream end of the branch connection pipe from below under the axial end face. 5. The branch joint according to any one of 4.