JP2013177918A - Branch joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attach a branch joint mainly to a straight pipe portion of a curved branch pipe member.SOLUTION: With respect to a straight pipe portion 14 of a curved branch pipe member 13 integrally having the straight pipe portion 14 and a bent pipe portion 15, the curved branch pipe member 13 being installed to a curved portion of a cable protection pipe 3, a length of a curved branch pipe-attaching surface 31 in the axial direction is smaller than a curved branch pipe attachable length 36 which is obtained by subtracting a pipe support member attaching margin 33, a branch joint attaching operation space 34, and a pipe connection nesting margin 35 from a length of the straight pipe portion 14, and greater than a curved branch pipe attaching necessary length 41 which is obtained by adding a protrusion setting length 37 in the axial direction of an inward protrusion edge portion 26, an adhesion margin 38 necessary for the outer circumference of the inward protrusion edge portion 26, and a margin 39 which should be ensured at an outer side of each adhesion margin 38.

Description

  The present invention relates to a branch joint.

  In recent years, as shown in FIG. 5, it has been promoted to embed cables 1 such as power cables and communication cables in the underground 2.

  In this way, by burying the cables 1 in the ground 2, it becomes possible to eliminate electric wires and utility poles from the ground, making the walking space barrier-free, maintaining a good living environment, and history It becomes possible to aim at the preservation of the townscape.

  The cables 1 described above are buried in the ground 2 in a state of being accommodated in the cable protection tube 3.

  Such a cable protection tube 3 is required to be divergent so that the number of connection destinations can be increased later. A branch joint 4 is used to branch the cable protection tube 3 (see, for example, Patent Document 1).

  As shown in FIG. 6, the conventional branch joint 4 is provided with a partially cylindrical mounting surface portion 5 that can contact the side surface of the cable protection tube 3, and projecting obliquely outward from the mounting surface portion 5. A branch opening 8 formed in the cable protection tube 3 is provided on the inner surface of the attachment surface 5 so as to surround the branch tube 6 and the edge of the attachment surface side opening 7 of the branch tube 6. It has an inward projecting edge portion 9 that can be inserted and arranged therein.

  The inward protruding edge portion 9 has a protruding height that is substantially the same as or higher than the thickness of the cable protection tube 3.

  Then, as shown in FIG. 7A, the obtuse angle side portion of the branch joint 4 has an inner surface-top portion that smoothly continues between the inner surface of the branch pipe portion 6 and the top portion of the inward protruding edge portion 9. An inter-continuous curved surface portion 11 is formed. Therefore, the inwardly projecting edge portion 9 has an obtuse angle side portion that is extremely wide with respect to the axial direction of the cable protection tube 3 as compared with other portions.

  Moreover, as shown in FIG.7 (b), the inward protruding edge part 9 is made into the thick-shaped ball edge part 12 in the acute angle side part of the branch joint 4. As shown in FIG.

JP 2007-51726 A

  In the cable protection tube 3 described above, since all the paths cannot be constituted by only the straight line portion, it is necessary to provide a curved portion for changing the direction in the middle. And it is necessary to be able to branch the cables 1 about such a curved portion.

  For this purpose, a curved branch pipe member 13 as shown in FIG. The curved branching pipe member 13 includes a straight pipe part 14 for attaching the branch joint 4, and a curved pipe part 15 for adjusting the path off the curved part of the cable protection pipe 3 by the straight pipe part 14. It is supposed to have as one. The end portion of the cable protection tube 3 on the straight tube portion 14 side is a pipe connection swallowing portion 16 for connection to another tube member constituting the cable protection tube 3. In addition, a receiving port 17 for connecting to another tube member constituting the cable protection tube 3 is provided at the end of the cable protection tube 3 on the bent tube portion 15 side. A pipe support member 18 for supporting the cable protection pipe 3 is attached to a boundary portion of the straight pipe portion 14 with the curved pipe portion 15.

  However, since the above-described branch joint 4 is made on the assumption that it is attached to the straight portion of the cable protection tube 3, the straight branch pipe member 13 having a sufficient length is not directly connected. It was difficult to attach the branch joint 4 to the pipe portion 14. For example, there has been a problem that the branch joint 4 cannot be mounted due to interference with the pipe support member 18 (interference part 19).

  In order to solve the above-mentioned problems, the invention described in claim 1 is provided with a mounting surface portion of a partial cylindrical surface that can be in contact with the side surface of the cable protection tube, and projecting obliquely outward from the mounting surface portion. A branch pipe portion and an inner surface of the attachment surface portion so as to surround the edge of the opening portion on the attachment surface portion of the branch pipe portion, and is inserted into the branch opening portion formed in the cable protection pipe. In the branch joint having a possible inward projecting edge portion, the straight pipe portion of the curved branch pipe member that is integrally provided with the straight pipe portion and the curved pipe portion and is installed in the curved portion of the cable protection pipe A mounting surface portion for a curved branch pipe that can be attached to the pipe, and the length in the axial direction of the mounting surface portion for the curved branch pipe includes a pipe support member installation allowance, a branch joint installation work space, and a pipe connection swallowing allowance. It is shorter than the installable length minus It is configured to be longer than the required installation length by adding the installation length of the protruding portion, the bonding margin necessary for the outer periphery of the inward protruding edge, and the margin to be secured outside each bonding margin It is said.

  The invention described in claim 2 is characterized in that, in the above, the inwardly projecting edge portion is a narrow-width edge portion having a width dimension equal to or less than a limit width over the entire circumference.

  According to a third aspect of the present invention, in the above, the inner surface of the branch pipe portion and the attachment for the curved branch pipe are formed on the inner surface of the obtuse angle side portion where the branch pipe portion branches at an obtuse angle with respect to the attachment surface portion for the curved branch pipe. A continuous curved surface portion between the inner surfaces that is smoothly continuous with the inner surface of the surface portion is formed, and an inner peripheral portion of the inwardly projecting edge located on the continuous curved surface portion between the inner surfaces is opposed to the continuous curved surface portion between the inner surfaces. It is characterized in that an inclined surface portion inclined with an angle smaller than 90 degrees is formed.

  According to a fourth aspect of the present invention, in the above, an outer peripheral notch portion is formed on an outer peripheral portion of an inward projecting edge portion located at an acute angle side portion where the branch pipe portion branches at an acute angle with respect to the mounting surface portion for the curved branch pipe. It is characterized by having formed.

  According to a fifth aspect of the present invention, in the above, the inner peripheral portion of the inward projecting edge located at the acute angle side portion where the branch pipe portion branches at an acute angle with respect to the mounting surface portion for the curved branch pipe, It is characterized by the formation of a notch.

  According to invention of Claim 1, the following effects can be acquired by the said structure. That is, a curved branch pipe mounting surface portion that can be attached to the straight pipe portion of the curved branch pipe member that is integrally provided with the straight pipe portion and the curved pipe portion and is installed in the curved portion of the cable protection pipe is provided. The length in the axial direction of the mounting surface portion for the curved branch pipe is shorter than the installable length minus the pipe support member installation allowance, the branch joint installation work space, and the pipe connection swallowing allowance, Longer than the required installation length, which is the axial length of the projecting edge, the bonding margin required for the outer periphery of the inner projecting edge, and the margin to be secured outside each bonding margin With this configuration, it is possible to attach the branch joint with a slight margin to the straight pipe portion of the curved branch pipe member for which it is difficult to ensure a sufficient length. Moreover, the adhesiveness of the branch joint with respect to the attachment surface part for curved branch pipes, airtightness, etc. can be ensured.

  According to invention of Claim 2, the following effects can be acquired by the said structure. That is, by setting the inward protruding edge portion as a narrow width edge portion having a width dimension equal to or smaller than the limit width over the entire circumference, the installation range of the inward protruding edge portion can be further narrowed. . Accordingly, it is possible to fit the mounting surface portion for the curved branch pipe to the above-described length.

  According to invention of Claim 3, the following effects can be acquired by the said structure. That is, between the inner surface of the obtuse angle side portion where the branch pipe portion branches obtusely with respect to the curved branch pipe mounting surface portion, the inner surface of the branch pipe portion and the inner surface of the curved branch pipe mounting surface portion are smoothly continuous In addition to forming a continuous curved surface portion, the inner peripheral portion of the inwardly protruding edge located on the continuous curved surface portion between the inner surfaces is inclined with an angle smaller than 90 degrees with respect to the continuous curved surface portion between the inner surfaces By forming the inclined surface portion to be formed, the inward protruding edge portion of the obtuse angle side portion can be formed into a more lean shape. Therefore, the branch opening formed in the cable protection tube is further reduced, and the mounting surface portion for the curved branch tube is reduced in size and weight, and the branch joint can be attached to the cable protection tube more advantageously. Become. At this time, it is possible to prevent the cables passed through the branch pipe portion from being damaged by providing the inclined surface portion on the inner peripheral portion of the inward protruding edge portion.

  According to invention of Claim 4, the following effects can be acquired by the said structure. That is, by forming an outer peripheral notch portion on the outer peripheral portion of the inwardly protruding edge portion positioned at the acute angle side portion where the branch pipe portion branches at an acute angle with respect to the mounting surface portion for the curved branch pipe, the inner portion of the acute angle side portion is formed. It becomes possible to make a direction protrusion edge part into a more lean shape. Therefore, the branch opening formed in the cable protection tube is further reduced, and the mounting surface portion for the curved branch tube is reduced in size and weight, and the branch joint can be attached to the cable protection tube more advantageously. Become.

  According to the fifth aspect of the present invention, the following operational effects can be obtained by the above configuration. That is, by forming an inner peripheral notch portion on the inner peripheral portion of the inwardly protruding edge located at the acute angle side portion where the branch pipe portion branches at an acute angle with respect to the mounting surface portion for the curved branch pipe, the acute angle side portion It is possible to make the inwardly projecting edge portion into a more lean shape. Accordingly, the mounting surface portion for the curved branch pipe can be made smaller and lighter. At this time, since the cables passed through the branch pipe part hardly come into contact with the inner peripheral part of the inner peripheral notch part at the acute angle side portion, the necessary strength is obtained without considering the damage of the cables 1. A large inner peripheral notch can be provided within a range that can be secured.

It is a side view which shows the state which attached the branch joint concerning the Example of this invention to the pipe member for curve branch. FIG. 2 is a side sectional view of FIG. 1. (A) is the enlarged view of the A section of FIG. 2, (b) is the enlarged view of the B section of FIG. It is a figure which shows the airtight test apparatus which performed the airtight test of the branch joint of this invention. It is a figure which shows the state which embeds cables in the ground. It is side sectional drawing of the branch joint concerning a prior art example. (A) is the enlarged view of the C section of FIG. 6, (b) is the enlarged view of the D section of FIG. It is a side view which shows the state which attaches the branch joint of FIG. 6 to the pipe member for curve branch.

  Hereinafter, examples embodying the present embodiment will be described in detail with reference to the drawings.

  1 to 4 show this embodiment.

<Configuration>
The configuration will be described below.

  As shown in FIGS. 1-3, the branch joint 21 which can branch the cable protective tube 3 for burying cables, such as a power cable and a communication cable, in the ground is provided.

  The branch joint 21 includes a partially cylindrical mounting surface portion 22 that can be in contact with the side surface of the cable protection tube 3, a branch pipe portion 23 projecting obliquely outward from the mounting surface portion 22, and the branch An inward protrusion that protrudes from the inner surface of the attachment surface portion 22 so as to surround the edge portion of the attachment surface portion side opening 24 of the tube portion 23 and can be inserted into the branch opening 8 formed in the cable protection tube 3. The edge portion 26 is integrally formed (see FIG. 2).

  The inward protruding edge portion 26 has a protruding height that is substantially the same as or higher than the thickness of the cable protection tube 3.

  In addition to the basic configuration as described above, the present embodiment has the following configuration.

(Configuration 1)
As the mounting surface portion 22 described above, a straight branching pipe member 13 that has a straight pipe portion 14 and a curved pipe portion 15 and is installed in a curved portion of the cable protection tube 3 as shown in FIG. A curved branch pipe mounting surface section 31 that can be mounted on the pipe section 14 is provided.

  The length of the curved branch pipe mounting surface 31 in the axial direction is determined from the length of the straight pipe section 14 in the axial direction, the pipe support member mounting allowance 33, the branch joint mounting work space 34, and the pipe connection drinking water. It is made to be substantially the same as or shorter than the mountable length 36 minus the insertion allowance 35.

  Further, as shown in FIG. 2, the mounting surface portion 31 for the curved branch pipe includes a protruding portion installation length 37 in the axial direction of the inner protruding edge portion 26, and an adhesive allowance 38 necessary for the outer periphery of the inner protruding edge portion 26. In addition, it is set to be equal to or longer than the required installation length 41 including a margin 39 to be secured outside each bonding margin 38.

(Supplementary explanation 1)
Here, as shown in FIG. 1, the straight pipe portion 14 of the above-described curved branch pipe member 13 is provided with a branch joint 21 or the like. Further, the curved pipe portion 15 is for correcting the path off the curved portion of the cable protection tube 3 by the straight pipe portion 14.

  The end portion of the cable protection tube 3 on the straight tube portion 14 side is a pipe connection swallowing portion 16 for connection to another tube member constituting the cable protection tube 3. In addition, a receiving port 17 for connecting to another tube member constituting the cable protection tube 3 is provided at the end of the cable protection tube 3 on the bent tube portion 15 side. A pipe support member 18 for supporting the cable protection pipe 3 is attached to a boundary portion of the straight pipe portion 14 with the curved pipe portion 15.

  The pipe support member attachment allowance 33 described above is literally an attachment allowance for attaching the pipe support member 18 to the straight pipe portion 14. The pipe support member mounting allowance 33 is the thickness of the pipe support member 18 and is approximately 50 mm to 100 mm.

  The work space 34 for attaching the branch joint is literally a work space necessary for attaching the branch joint 21. The work space 34 for installing the branch joint is approximately 20 mm to 50 mm.

  The pipe connection swallowing allowance 35 is literally a swallowing allowance for connecting the straight pipe portion 14 to an adjacent pipe member.

  Further, the protruding portion installation length 37 in the axial direction of the inner protruding edge portion 26 is literally the length of the installation range with respect to the axial direction of the inner protruding edge portion 26. This protrusion installation length 37 is set as described later.

  The bonding allowance 38 necessary for the outer periphery of the inward protruding edge portion 26 is literally the cable protection tube 3 (straight tube portion 14 of the curve branching tube member 13) of the mounting surface portion 22 (curved branching tube mounting surface portion 31). It is the width dimension of the adhesion surface to.

  The margin allowance 39 is literally the width dimension of the allowance space necessary to ensure the adhesion by the adhesion allowance 38 described above.

  FIG. 4 shows an airtight test apparatus 43 that has performed an airtight test in order to determine the size of the above-described bonding allowance 38. This hermetic test device 43 is provided through a frame 45 that can hold each opening of the cable protection tube 3 (test piece) to which the branch joint 21 is bonded in a sealed state with a sealing plug 44 and one of the sealing plugs 44. An air supply hose 47 capable of supplying compressed air from the air supply source 46 to the inside of the cable protection tube 3 (a test piece thereof), a pressure gauge 48 and an on-off valve 49 provided in the middle of the air supply hose 47 It has.

  As a result of the airtight test by the airtight test device 43 described above, it was confirmed that the bonding allowance 38 on both sides of the branch opening 8 is determined not by the pipe diameter but by the performance of the adhesive. And the bonding allowance 38 by the adhesive used was about 20 mm.

  The margin 39 is preferably set to an optimal size that is neither too wide nor too narrow. In this case, as a result of conducting the construction experiment, it was sufficient if there was almost the same length or width as the bonding allowance 38. Therefore, the margin 39 is set to about 20 mm (20 mm ± 10 mm), for example.

  In order to clarify the bonding allowance 38, the outer peripheral portion of the bonding allowance 38 is explicitly expressed so as to surround the outer periphery of the inward protruding edge portion 26 with respect to the back surface side of the curved branch pipe mounting surface portion 31. For this purpose, a range designation line portion 50 or the like may be provided. This range designation line portion 50 can be formed integrally when the branch joint 21 is molded. This range designation line portion 50 is a very slight trace that can be confirmed with the naked eye so as not to hinder adhesion (a slight groove or convex having a depth or height of about 1 mm or less). If it is enough.

  Note that the above-described required installation length 41 is shorter than the above-described installation possible length 36 (required installation length 41 <installable length 36).

(Configuration 2)
And let the above-mentioned inward protrusion edge part 26 be the narrow edge part 51 which has a width dimension below a limit width over the perimeter.

(Supplementary explanation 2)
Here, the width dimension equal to or less than the limit width is a minimum width dimension required for function and design, with a slight margin. More specifically, the width dimension is about 3 times or less (about 0.5 to 3 times) the normal thickness of the mounting surface portion 31 for the curved branch pipe. If this is less than 0.5 times, it is difficult to ensure the strength of the inwardly protruding edge portion 26, and if it is more than about 3 times, the protruding portion installation length 37 in the axial direction of the inwardly protruding edge portion 26 is increased. It becomes because it becomes too much and becomes unsuitable for attaching to the straight pipe part 14 of the pipe member 13 for curve branching.

  In this case, it is preferable that the inward protruding edge portion 26 has a uniform width over the entire circumference, but the width dimension may be partially changed.

(Configuration 3)
Furthermore, as shown to Fig.3 (a), the inner surface of the branch pipe part 23 and the curve inside the obtuse angle side part 52 where the branch pipe part 23 branches obtusely with respect to the above-mentioned curved branch pipe attachment surface part 31 A continuous curved surface portion 53 between the inner surfaces, in which the inner surface of the branch pipe mounting surface portion 31 continues smoothly, is formed.

  Then, the inner peripheral portion of the inwardly projecting edge portion 26 located on the continuous curved surface portion 53 between the inner surfaces has an angle smaller than 90 degrees with respect to the continuous curved surface portion 53 between the inner surfaces (in the lower right direction in the figure). ) An inclined surface portion 54 that is inclined is formed.

(Supplementary explanation 3)
Here, it is preferable that the continuous curved surface portion 53 between the inner surfaces is formed so that the thickness between the inner and outer surfaces is substantially uniform (uniform thickness). The continuous curved surface portion 53 between the inner surfaces is a continuous curved surface having no conspicuous steps or shape change on the inner surface.

  The inclined surface portion 54 described above preferably has a range of approximately 30 ° to 60 °. This is because if the angle is smaller than 30 °, the width dimension of the inwardly projecting edge portion 26 is increased, and if it is larger than 60 °, both end portions of the inclined surface portion 54 are angular, and are rubbed when passing cables. This is because cables may be damaged. In this case, the intermediate 45 degrees is used.

  In addition, a chamfering process, R process, etc. can also be given to the boundary part between the continuous curved surface part 53 between inner surfaces, and the inclined surface part 54, and the boundary part between the inclined surface part 54 and the top part of the inward protrusion edge part 26. .

(Configuration 4)
As shown in FIG. 3B, the outer peripheral portion of the inwardly projecting edge portion 26 located at the acute angle side portion 55 where the branch pipe portion 23 branches at an acute angle with respect to the above-described curved branch pipe attachment surface portion 31 A notch 56 is formed.

(Supplementary explanation 4)
Here, the outer periphery notch part 56 is, for example, a concave part having an R shape in side view. However, the shape of the outer periphery notch part 56 is not restricted to this. For example, it can be a stepped portion.

(Configuration 5)
An inner peripheral notch 57 is formed on the inner peripheral portion of the inwardly protruding edge portion 26 located at the acute angle side portion 55 where the branch pipe portion 23 branches at an acute angle with respect to the curved branch pipe attachment surface portion 31 described above.

(Supplementary explanation 5)
Here, the inner peripheral notch 57 is a stepped portion or the like. However, the shape of the inner peripheral notch 57 is not limited to this. For example, it may be a concave portion having an R shape in side view.

<Action>
The operation of this embodiment will be described below.

  When attaching the branch joint 21 to the straight pipe portion 14 of the curved branch pipe member 13, first, the branch opening 8 is formed in the straight pipe portion 14 of the curved branch pipe member 13. This branch opening 8 is processed on site.

  More specifically, a hole shape that is the same as or slightly larger than the inwardly projecting edge portion 26 of the branch joint 21 is drawn on the straight pipe portion 14 of the curved branch pipe member 13 with a marking line, and the inside of the marking line. Is cut using a dedicated tool or a normal tool such as a hole saw to form the opening 8 for branching.

  Next, an adhesive is applied by hand to the entire portion of the bonding allowance 38 on the inner surface 31 of the curved branch pipe attachment surface 31 of the branch joint 21.

  Then, the branch joint 21 to which the adhesive is applied is inserted into the opening 8 for branching with the inwardly protruding edge portion 26, and the mounting surface portion 31 for the curved branching tube is brought into contact with the side surface of the straight pipe portion 14 of the curved branching tube member 13. Install in contact.

  Finally, the branch joint 21 is secured to the outer periphery of the straight pipe portion 14 of the curved branch pipe member 13 using a band member (not shown).

  As described above, the branch joint 21 is attached to the straight pipe portion 14 of the curved branch pipe member 13 by both adhesion and lashing.

  <Effect> According to this embodiment, the following effects can be obtained.

(Effect 1)
Curved branch pipe mounting surface portion that can be attached to the straight pipe portion 14 of the curved branch pipe member 13 that is integrally provided with the straight pipe portion 14 and the curved pipe portion 15 and is installed on the curved portion of the cable protection tube 3. 31 is provided, and the length in the axial direction of the curved branch pipe mounting surface portion 31 is the installable length obtained by subtracting the pipe support member mounting allowance 33, the branch joint attaching work space 34, and the pipe connecting swallowing allowance 35. 36, and should be secured outside the bonding allowance 38 and the bonding allowance 38 required for the outer periphery of the inward protruding edge 26. Since it is configured to be longer than the required installation length 41 including the allowance 39, it is slightly marginal with respect to the straight pipe portion 14 of the curve branching pipe member 13 in which it is difficult to ensure a sufficient length. Thus, the branch joint 21 can be attached. Moreover, the adhesiveness of the branch joint 21 with respect to the attachment surface part 31 for curved branch pipes, airtightness, etc. can be ensured.

(Effect 2)
By setting the inward protruding edge portion 26 to be a narrow width edge portion 51 having a width dimension equal to or smaller than the limit width over the entire circumference, the installation range of the inward protruding edge portion 26 can be further narrowed. . Accordingly, it is possible to fit the curved branch pipe mounting surface portion 31 to the above-described length.

(Effect 3)
Between the inner surface of the obtuse angle side portion 52 where the branch pipe portion 23 branches at an obtuse angle with respect to the mounting surface portion 31 for the curved branch pipe, and the inner surface where the inner surface of the branch pipe portion 23 and the inner surface of the curved branch pipe mounting surface portion 31 continue smoothly. While forming the continuous curved surface part 53, it has an angle smaller than 90 degrees with respect to the continuous curved surface part 53 between inner surfaces in the inner peripheral part of the inward protrusion edge part 26 located on the continuous curved surface part 53 between inner surfaces. By forming the inclined surface part 54 which inclines, it becomes possible to make the inward protruding edge part 26 of the obtuse angle side part 52 into a more lean shape. Accordingly, the branch opening 8 formed in the cable protection tube 3 is further reduced, and the curved branch tube mounting surface 31 is reduced in size and weight, and the branch joint 21 is attached to the cable protection tube 3 more advantageously. Will be able to.

  At this time, it is possible to prevent the cables passed through the branch pipe portion 23 from being damaged by providing the inclined surface portion 54 on the inner peripheral portion of the inward protruding edge portion 26.

(Effect 4)
By forming the outer peripheral cutout portion 56 on the outer peripheral portion of the inward protruding edge portion 26 located at the acute angle side portion 55 where the branch pipe portion 23 branches at an acute angle with respect to the mounting surface portion 31 for the curved branch pipe, the acute angle side portion is formed. It is possible to make the inwardly projecting edge portion 55 of 55 have a more lean shape. Accordingly, the branch opening 8 formed in the cable protection tube 3 is further reduced, and the curved branch tube mounting surface 31 is reduced in size and weight, and the branch joint 21 is attached to the cable protection tube 3 more advantageously. Will be able to.

(Effect 5)
By forming the inner peripheral notch portion 57 on the inner peripheral portion of the inward projecting edge portion 26 located at the acute angle side portion 55 where the branch pipe portion 23 branches at an acute angle with respect to the mounting surface portion 31 for the curved branch pipe, an acute angle is obtained. It becomes possible to make the inward protruding edge portion 26 of the side portion 55 into a more lean shape. Accordingly, the curved branch pipe mounting surface portion 31 can be made smaller and lighter.

  At this time, since the cables passed through the branch pipe portion 23 hardly come into contact with the inner peripheral portion of the inner peripheral notch 57 of the acute angle side portion 55, it is necessary without considering the damage of the cables. A large inner peripheral notch 57 can be provided within a range in which sufficient strength can be secured.

  Although the embodiments of the present invention have been described in detail with reference to the drawings, the embodiments are only examples of the present invention, and the present invention is not limited to the configurations of the embodiments. Needless to say, design changes and the like within a range not departing from the gist of the invention are included in the present invention. Further, for example, when each embodiment includes a plurality of configurations, it is a matter of course that possible combinations of these configurations are included even if not specifically described. Further, when a plurality of embodiments and modifications are shown, it is needless to say that possible combinations of configurations extending over these are included even if not specifically described. Further, the configuration depicted in the drawings is of course included even if not particularly described. Further, when there is a term of “etc.”, it is used in the sense that the equivalent is included. In addition, when there are terms such as “almost”, “about”, “degree”, etc., they are used in the sense that they include those in the range and accuracy recognized by common sense.

DESCRIPTION OF SYMBOLS 3 Cable protection pipe 8 Branching opening part 13 Curved branching pipe member 14 Straight pipe part 15 Curved pipe part 21 Branching joint 23 Branching pipe part 24 Mounting surface part side opening part 26 Inward protruding edge part 31 Curved branch pipe attachment surface part 33 Piping Mounting space for supporting member 34 Work space for installing branch joint 35 Swallowing allowance for pipe connection 36 Installable length 37 Protrusion installation length 38 Adhesive allowance 39 Margin allowance 41 Required length 51 Narrow edge portion 52 Obtuse angle side portion 53 Continuous curved surface portion between inner surfaces 54 Inclined surface portion 55 Acute angle side portion 56 Outer peripheral notch portion 57 Inner peripheral notch portion

Claims (5)

A mounting surface portion of a partial cylindrical surface that can come into contact with the side surface of the cable protection tube, a branch pipe portion projecting obliquely outward from the mounting surface portion, and an edge of the opening on the mounting surface portion side of the branch pipe portion In the branch joint having an inward projecting edge portion projecting from the inner surface of the mounting surface portion so as to surround the portion and insertable into the branch opening formed in the cable protection tube,
A curved branch pipe mounting surface part that can be attached to the straight pipe part of the curved branch pipe member that is integrally installed with the straight pipe part and the curved pipe part and is installed in the curved part of the cable protection pipe,
The length in the axial direction of the mounting surface portion for the curved branch pipe is shorter than the installable length minus the pipe support member installation allowance, the branch joint installation work space, and the pipe connection swallowing allowance,
From the required installation length, which is the axial installation length of the inner protruding edge, the bonding margin required for the outer periphery of the inner protruding edge, and the margin to be secured outside each bonding margin A branch joint characterized by being configured to be longer.   The branch joint according to claim 1, wherein the inwardly projecting edge portion is a narrow-width edge portion having a width dimension equal to or less than a limit width over the entire circumference. An inner surface continuous curved surface in which the inner surface of the branch pipe portion and the inner surface of the attachment surface portion for the curved branch pipe are smoothly connected to the inner surface of the obtuse angle side portion where the branch pipe portion branches at an obtuse angle with respect to the mounting surface portion for the curved branch pipe. Forming the part,
An inclined surface portion that is inclined at an angle smaller than 90 degrees with respect to the continuous curved surface portion between the inner surfaces is formed on an inner peripheral portion of the inwardly projecting edge portion located on the continuous curved surface portion between the inner surfaces. The branch joint according to claim 1 or 2, wherein the branch joint is characterized.   The outer periphery notch part is formed in the outer peripheral part of the inward projecting edge part located in the acute angle side part where a branch pipe part branches at an acute angle shape with respect to the said mounting surface part for curved branch pipes, The 1st thru | or Claim characterized by the above-mentioned. Item 4. The branch joint according to any one of items 3 to 4.   2. An inner peripheral notch is formed at an inner peripheral portion of an inwardly projecting edge located at an acute angle side portion where the branch pipe portion branches at an acute angle with respect to the mounting surface portion for the curved branch pipe. The branch joint according to any one of claims 4 to 4.