JP4708454B2 - Joint for branch - Google Patents

Description

  The present invention is not limited to a branch joint, particularly a main pipe such as a gas pipe, and of course the branch pipe can be connected to the main pipe of weak strength even when the branch pipe is connected to a weak main pipe. It is possible to reliably prevent the adverse effect of the main pipe due to the bending stress acting locally, and to apply the reduced diameter stress uniformly to the end of the pressing sleeve piece when fastening the pressing sleeve piece. The present invention relates to a branch joint that can reliably prevent the adverse effect of the pressing sleeve piece due to the concentration of the reduced diameter stress.

  As a branch joint for connecting a branch pipe to a main pipe such as a cast iron gas pipe buried in the ground, there is one disclosed in Japanese Utility Model Publication No. 46-35063. Hereinafter, this branch joint is referred to as a conventional branch joint and will be described with reference to the drawings.

  FIG. 10 is a partial cross-sectional view showing a state in which a branch pipe is connected to the main pipe by a conventional branch joint, FIG. 11 is a bottom view showing a branch sleeve piece of the conventional branch joint, and FIG. It is a bottom view which shows the sleeve piece for a press of a coupling.

  As shown in FIGS. 10 to 12, the conventional branch joints attached to the branch locations of the main pipe 11 are the branch sleeve piece 12 and the press sleeve piece 13 each formed in a semi-cylindrical shape with the same inner diameter. It is made up of.

A branch portion 14 having a branch pipe opening 14 </ b> A is formed at the center of the branch portion sleeve piece 12, and fulcrum protrusions 12 </ b> A are formed on the inner surfaces of the branch portion sleeve pieces 12 on both sides of the branch portion 14. It is formed in a ring shape. The branch pipe opening 14A is internally threaded. By forming the fulcrum projection 12A, a gap (L ₁ ) is formed between the outer surface of the branching sleeve piece 12 outside the fulcrum projection 12A and the outer surface of the main pipe 11. By forming the gap (L ₁ ), upward bending of the main pipe 11 with the fulcrum projection 12A as a fulcrum is allowed. A ring-shaped packing 15 made of rubber or the like is inserted between the periphery of the opening 14 </ b> A of the branch portion 14 and the main pipe 11. Pressing protrusions 13 </ b> A are formed on the inner surfaces of both end portions of the pressing sleeve piece 13. By forming the pressing protrusion 13A, a gap (L ₂ ) is formed between the inner surface of the pressing sleeve piece 13 and the outer surface of the main pipe 11 between the pressing protrusions 13A. By forming the gap (L ₂ ), when the sleeve pieces 12 and 13 are fastened, the main pipe 11 is pushed by the pressing protrusion 13A, and the main pipe 11 is moved with the fulcrum protrusion 12A as a fulcrum. A bending stress that bends upward acts. The branching sleeve piece 12 and the pressing sleeve piece 13 are fastened in a cylindrical shape by inserting bolts 16 into bolt holes 12C and 13C formed in the fastening flanges 12B and 13B and tightening nuts 17. The

  According to the conventional branch joint configured as described above, the branch pipe is connected to the middle of the main pipe as follows.

  First, a main groove 11 is exposed by excavating a working groove in the ground. Next, the branching sleeve piece 12 and the pressing sleeve piece 13 are applied to the outer surface of the branch pipe connecting portion of the main pipe 11, and the sleeve pieces 12 and 13 are fastened by the bolt 16 and the nut 17. A ring-shaped packing 15 is inserted into the branch portion 14 of the branch portion sleeve piece 12. Next, a hole 11 </ b> A is made in the main pipe 11 from a branch pipe opening 14 </ b> A of the branch portion sleeve piece 12 through a drill (not shown) of a drilling machine. Then, when the branch pipe 18 with the male thread cut at the tip portion is screwed into the branch pipe opening 14A with the female thread cut, the operation of connecting the branch pipe 18 to the main pipe 11 is completed. When the connection work is completed in this way, the work groove is filled back.

  Thus, according to the conventional branch joint, the branch pipe 18 can be reliably connected in the middle of the main pipe 11. In addition, when the branching sleeve piece 12 and the pressing sleeve piece 13 are fastened by the bolt 16 and the nut 17, the pressing projection 13 </ b> A of the pressing sleeve piece 13 faces the lower surface of the main pipe 11 and the branching sleeve piece 12. Since the fulcrum projection 12A is pressed as a fulcrum, upward bending stress acts on the main pipe 11 around the hole 11A.

  If the hole 11A is opened in the main pipe 11 for the connection of the branch pipe 18, the strength of that portion is lowered. Thus, when uneven settlement occurs in the buried ground of the main pipe 11 with the holes 11A, downward bending stress acts on the main pipe 11 with the hole 11A as a fulcrum. As a result, the main pipe 11 may have a crack starting from the hole 11A, leading to a breakage of the main pipe 11.

  However, as described above, the conventional branch joint has an upward bending stress centered on the hole 11A in the main pipe 11, that is, the hole 11A acting on the main pipe 11 due to uneven settlement of the buried ground, etc. If an upward bending stress that cancels the downward bending stress is applied to the main pipe 11 in advance, adverse effects such as cracks occurring in the main pipe 11 can be effectively prevented.

Japanese Utility Model Publication No. 46-35063

  However, the conventional branch joint has the following problems.

  When the bending sleeve piece 12 and the pressing sleeve piece 13 are fastened by the bolt 16 and the nut 17, when the upward bending stress about the hole 11 </ b> A is applied to the main pipe 11, the main pipe 11 is aged. If the main pipe 11 is weak in strength or material, the main pipe 11 may be adversely affected.

  Originally, if a branch joint is manufactured for each main pipe 11 having a different outer diameter so that the inner diameter of the branch joint matches the outer diameter of the main pipe 11, as shown in FIG. Since the pressing protrusion 13A of the piece 13 and the outer surface of the main pipe 11 are in surface contact with each other, the bending stress acting on the main pipe 11 is dispersed. As a result, the main pipe 11 is not locally applied and There is no fear of adverse effects. However, if the inner diameter of the branch joint and the outer diameter of the main pipe 11 do not match, as shown in FIG. 5B, the pressing protrusion 13A of the pressing sleeve piece 13 and the outer surface of the main pipe 11 Since this is a point contact, the bending stress acting on the main pipe 11 is concentrated at one point. As a result, when the strength of the main pipe 11 is weak, the main pipe 11 may be adversely affected.

  As described above, there is no problem if a branch joint is manufactured for each main pipe 11 having a different outer diameter so that the inner diameter of the branch joint matches the outer diameter of the main pipe 11, but it is buried for a long time. Since the outer diameter of the main pipe 11 has changed due to rust or the like, it is practically impossible to manufacture a branch joint for each main pipe 11 in accordance with the rust and the like in terms of cost and construction period. Moreover, since the pipe diameter of the main pipe 11 to be embedded is different for each pipe, it is practically impossible to manufacture a branch joint for each main pipe 11 from this point.

  Therefore, the object of the present invention is to connect the branch pipe to the main pipe such as a gas pipe without fail, and to connect the branch pipe to the main pipe having low strength. It is possible to reliably prevent the adverse effect of the main pipe due to the bending stress acting on the sleeve, and to apply the reduced diameter stress uniformly to the end of the pressing sleeve piece when the pressing sleeve piece is fastened. An object of the present invention is to provide a branch joint that can reliably prevent the adverse effect of a pressing sleeve piece due to the concentration of radial stress.

  The present invention has been made to achieve the above object, and is characterized by the following.

  The invention according to claim 1 is a branch joint for connecting a branch pipe in the middle of a main pipe, a semi-cylindrical branch sleeve piece formed with a branch section to which the branch pipe is connected, A pressing sleeve piece fastened to the branching sleeve piece, and a fulcrum projection that abuts the outer surface of the main pipe is formed on the inner surface of the branching sleeve piece in the vicinity of the branching part. The pressing sleeve piece is formed on the inner surface of both ends of the pressing sleeve piece with a pressing projection that contacts the outer surface of the main pipe outside the outer surface of the main pipe with which the fulcrum protrusion comes into contact. A plurality of main ribs are formed along the axial direction of the pressing sleeve piece on the outer surface other than the both end portions.

  According to a second aspect of the present invention, in the first aspect of the present invention, the thickness of both end portions of the pressing sleeve piece decreases from the circumferential end portion of the pressing sleeve piece toward the circumferential central portion. It is characterized by being formed.

  The invention described in claim 3 is characterized in that, in the invention described in claim 1, reinforcing flanges are formed on the outer surfaces of both end portions of the pressing sleeve piece.

According to a fourth aspect of the present invention, in the third aspect of the present invention, a secondary rib is formed from the surface on the main rib side of the central portion in the circumferential direction of the reinforcing flange toward the end of the main rib . It has the characteristics.

According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, on the inner peripheral surfaces of both sides of the pressing sleeve piece, the inner sides of the pressing protrusions are inward of each other. An inclined surface is formed, and the inclined surface is fastened between the branch portion sleeve piece and the branch portion sleeve piece, so that the main pipe has the fulcrum protrusion as a fulcrum by the pressing force of the pressing protrusion. When deformed, it is in close contact with the outer surface of the main pipe, thus increasing the contact area between the main pipe and the pressing sleeve piece.

  According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, the main rib is the pressing sleeve corresponding to the space between the inclined surfaces at both ends of the pressing sleeve piece. It is characterized by being formed parallel to the outer surface of the piece.

  According to a seventh aspect of the present invention, in the invention according to any one of the first to sixth aspects, the height of the end portion of the main rib is continuously increased toward the end portion of the pressing sleeve piece. It is characterized by being formed low.

  The invention according to claim 8 is the invention according to any one of claims 1 to 7, wherein a sealing member interposed between the sleeve piece for branching portion and the sleeve piece for pressing, and a branching portion And a pressing member that prevents the seal member from being pushed outward when the sleeve piece for pressing and the pressing sleeve piece are fastened.

  The invention described in claim 9 is characterized in that, in the invention described in claim 8, the seal member is made of soft rubber.

  A tenth aspect of the invention is characterized in that, in the invention according to any one of the first to ninth aspects, the branching sleeve piece and the pressing sleeve piece are made of cast iron. is there.

  According to this invention, even if the inner diameter of the branch joint does not match the outer diameter of the main pipe and the strength of the main pipe is weak, the pressing protrusion of the pressing sleeve piece and the outer surface of the main pipe Since it is possible to make surface contact with the main pipe such as a gas pipe, the branch pipe can be securely connected to the main pipe. In addition, it is possible to reliably prevent the adverse effect of the main pipe due to the bending stress acting on the surface, and by applying the reduced diameter stress uniformly to the end of the pressing sleeve piece when fastening the pressing sleeve piece, An adverse effect on the pressing sleeve piece due to the concentration of the reduced diameter stress can be reliably prevented.

  Next, an embodiment of the branch joint of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view of the branch joint of the present invention mounted on the main pipe as viewed from above, and FIG. 2 is a perspective view of the branch joint of the present invention mounted on the main pipe as viewed from below. 3 is a cross-sectional view taken along the line AA in FIG. 1, and FIG. 4 is a cross-sectional view taken along the line BB in FIG.

1 to 4, reference numeral 1 is a main pipe such as a gas pipe, 2 is a semi-cylindrical cast iron sleeve piece for a branch part, and a branch part 4 to which the branch pipe 3 is connected is provided at the center. Is formed. The branch 4 is formed with an opening 4 </ b> A that is opened in the main pipe 1 and communicates with a hole 1 </ b> A described later. An internal thread is cut in the opening 4A. On the inner surface of the branch portion sleeve piece 2 on both sides of the branch portion 4, there are formed fulcrum projections 2A that contact the outer surface of the main pipe 1 (see FIG. 4). By forming the fulcrum projection 2A, a gap (L ₁ ) is formed between the inner surface of the branching sleeve piece 2 outside the fulcrum projection 2A and the outer surface of the main pipe 1. By forming this gap (L ₁ ), upward bending of the main pipe 1 with the fulcrum projection 2A as a fulcrum is allowed. A ring-shaped packing 8 made of rubber or the like is inserted between the periphery of the opening 4A of the branch portion 4 and the main pipe 1 (see FIG. 4).

Reference numeral 5 denotes a semi-cylindrical cast iron pressing sleeve piece fastened to the branch portion sleeve piece 2. The branching sleeve piece 2 and the pressing sleeve piece 5 are obtained by inserting the bolt 6 into the bolt holes 2C and 5C of the fastening flanges 2B and 5B formed on the sleeve pieces 2 and 5 and tightening the nut 7. Fastened in a cylindrical shape. Pressing protrusions 5 </ b> A are formed on the inner surfaces of both ends of the pressing sleeve piece 5. The pressing protrusion 5A abuts on the outer surface of the main pipe 1 outside the outer surface of the main pipe 1 with which the fulcrum protrusion 2A of the branching sleeve piece 2 abuts. By forming the pressing protrusion 5A, a gap (L ₂ ) is formed between the inner surface of the pressing sleeve piece 5 and the outer surface of the main pipe 1 between the pressing protrusions 5A on both sides. By forming this gap (L ₂ ), when the sleeve pieces 2 and 5 are fastened, the main pipe 1 is pushed by the pressing protrusion 5A, and the fulcrum protrusion 2A is used as a fulcrum. Bending stress is applied to bend the wire upward. (See FIG. 4).

As shown in FIG. 4, an inclined surface (S) in contact with the outer surface of the main pipe 1 that is deformed with the fulcrum projection 2 </ b> A as a fulcrum is formed inside the pressing projection 5 </ b> A. That is, the inclined surfaces (S) are formed inward of the pressing protrusions 5 </ b> A on the inner peripheral surfaces on both sides of the pressing sleeve piece 5. The deformation of the main pipe 1 is indicated by a two-dot chain line in FIG. By forming the inclined surface (S), the contact area between the pressing protrusion 5A of the pressing sleeve piece 5 and the outer surface of the main pipe 1 is increased. That is, the outer surface of the main pipe 1 is in contact with both the pressing protrusion 5A and the inclined surface (S), and the bending stress acting on the main pipe 1 is dispersed accordingly, and the main pipe 1 is It is possible to prevent adverse effects.

  On the outer surface of the pressing sleeve piece 5 other than the outer surfaces of the both ends, that is, on the outer surface of the pressing sleeve piece 5 corresponding to the inclined surface (S) of the both ends of the pressing sleeve piece 5, A plurality of main ribs 9 are formed in parallel along the axial direction. By forming the main rib 9, a groove 9 </ b> A is formed between the main ribs 9.

  Thus, the following effects are brought about by forming the main rib 9 on the outer surface of the pressing sleeve piece 5.

  When the branching sleeve piece 2 and the pressing sleeve piece 5 are fastened with bolts 6 and nuts 7, the pressing sleeve piece 5 has a bending stress that bends the main pipe 1 upward with the fulcrum projection 2A as a fulcrum. Works. At the same time, on the pressing sleeve piece 5, a diameter reducing stress for reducing the diameter of the pressing sleeve piece 5 acts on the groove 9 </ b> A between the main ribs 9. As a result, as shown in FIG. 5A, the pressing sleeve piece 5 is deformed so as to wrap the main pipe 1, so that the inner diameter of the branch joint and the outer diameter of the main pipe 1 do not match before fastening. Even so, the pressing projection 5A of the pressing sleeve piece 5 and the outer surface of the main pipe 1 are in surface contact. As a result, since the bending stress acting on the main pipe 1 is dispersed and does not act locally, there is no possibility that the main pipe is adversely affected by the bending stress acting locally on the main pipe 1. The strength of the pressing sleeve piece 5 is sufficiently ensured by the main rib 9.

  As described above, the main ribs 9 are not formed at both end portions of the pressing sleeve piece 5, for the following reason.

  Even when the main rib 9 is formed over the entire length in the axial direction of the pressing sleeve piece 5, the pressing sleeve piece 5 is deformed so as to wrap the main pipe 1, so that bending stress acts on the main pipe 1 locally. No effect is brought about. However, in this case, as a result of concentrated stress acting on the groove 9A between the main ribs 9 at the end of the pressing sleeve piece 5, the pressing sleeve piece 5 may be adversely affected.

  On the other hand, the main rib 9 is not formed on the end portion of the pressing sleeve piece 5 but only on the outer surface of the pressing sleeve piece 5 corresponding to between the inclined surfaces (S) at both ends of the pressing sleeve piece 5. If the main rib 9 is formed, the groove 9A in which the reduced diameter stress is concentrated does not exist at the end of the pressing sleeve piece 5, so that the reduced diameter stress acts uniformly on the end of the pressing sleeve piece 5. As a result, it is possible to reliably prevent adverse effects of the pressing sleeve piece due to the concentrated stress acting on the end of the pressing sleeve piece 5.

  If the height of the end portion of the main rib 9 is continuously lowered toward the end portion of the pressing sleeve piece 5, the reduced diameter acting on the groove 9 </ b> A of the pressing sleeve piece 5 at the end portion of the main rib 9. The stress changes continuously. In other words, the reduced diameter stress acting on the groove 9A continuously decreases from the higher to the lower height of the main rib 9, and the excessive reduced diameter stress does not act on the pressing sleeve piece 5. On the other hand, as shown by a two-dot chain line in FIG. 4, when the height of the main rib 9 is the same over its entire length, the reduced stress distribution has a boundary at the position where the main rib 9 is removed. The pressing sleeve piece 5 is adversely affected as a result of abrupt change and an excessively reduced diameter stress acting on the pressing sleeve piece 5.

  In FIG. 2, as shown by (M), if the thickness of both end portions of the pressing sleeve piece 5 is formed thinly from the circumferential end portion of the pressing sleeve piece 5 toward the circumferential central portion, the diameter is reduced. The stress dispersion effect can be further enhanced.

  According to the branch joint of the present invention configured as described above, the branch pipe is connected to the middle of the main pipe as follows.

  First, a work groove is excavated in the ground to expose the main pipe 1. Next, the branching sleeve piece 2 and the pressing sleeve piece 5 are applied to the branch pipe connecting portion of the main pipe 1, and the sleeve pieces 2 and 5 are fastened by the bolt 6 and the nut 7. In addition, the ring-shaped packing 8 is inserted in the branch part 4 of the sleeve part 2 for branch parts before fastening. Next, a hole 1A is made in the main pipe 1 from the branch pipe opening 4A of the branch portion sleeve piece 2 through a drill (not shown) of a drilling machine. Next, when the branch pipe 3 is screwed into the branch pipe opening 4A, the connection work of the branch pipe 3 to the main pipe 1 is completed. When the connection work is completed in this way, the work groove is filled back.

  When the branch sleeve piece 2 and the pressing sleeve piece 5 are fastened by the bolt 6 and the nut 7, the main pipe 1 is indicated by a two-dot chain line in FIG. 4 by the pressing protrusion 5A of the pressing sleeve piece 5. As described above, upward bending stress with the fulcrum projection 2A of the branch sleeve piece 2 acting as a fulcrum acts, but the pressing sleeve piece 5 is formed with the main rib 9, and the groove 9A between the main ribs 9 is formed. As a result of the concentration of the reduced diameter stress, the pressing sleeve piece 5 is deformed so as to wrap the main pipe 1 as shown in FIG. 5A, and the pressing projection 5A and the outer surface of the main pipe 1 are in surface contact with each other. To do. As a result, the upward bending stress with the fulcrum projection 2A as a fulcrum is dispersed, so that the strength of the main pipe 1 is reduced and the inner diameter of the branch joint does not match the outer diameter of the main pipe 1 Even so, the main pipe is not locally subjected to bending stress, and the main pipe 1 is not adversely affected by the local bending stress.

  In addition, since the main rib 9 is not formed at the end portion of the pressing sleeve piece 5, it is ensured that the pressing sleeve piece 5 is adversely affected by the concentration of the reduced diameter stress on the end portion of the pressing sleeve piece 5. Can be prevented.

  Next, another branch joint of the present invention will be described with reference to the drawings.

  FIG. 6 is a perspective view of another branch joint of the present invention mounted on the main pipe as viewed from above, and FIG. 7 is a plan view of another branch joint of the present invention mounted on the main pipe from below. FIG. 8 is a cross-sectional view taken along the line CC of FIG. 6, and the same reference numerals as those in FIGS. 1 to 4 denote the same components.

As shown in FIGS. 6 to 8, another branch joint of the present invention is the above-described branch joint in which main ribs are not formed at both ends, and reinforcing flanges on the outer surfaces of both ends of the pressing sleeve piece 5. 5D is formed. By forming the reinforcing flange 5D, the strength of the end portion of the pressing sleeve piece 5 is increased, so that the effect of dispersing the reduced diameter stress can be further enhanced. In this case, the reduced diameter stress is concentrated in the central portion in the circumferential direction of the reinforcing flange 5D, but in order to disperse the stress, it extends in the axial direction of the pressing sleeve piece 5 in the central portion in the circumferential direction of the reinforcing flange 5D. What is necessary is just to form the subrib 5E. The secondary rib 5E is formed in the direction of the end of the main rib 9 from the surface on the main rib 9 side in the central portion in the circumferential direction of the reinforcing flange 5D.

  In addition, the dispersion effect of the reduced diameter stress acting on the end portion of the pressing sleeve piece 5 can be obtained by changing the thickness of the end portion of the pressing sleeve piece 5 as shown in FIG. As shown, the reinforcing flange 5D is formed at the end of the pressing sleeve piece 5. However, which one is adopted can be determined according to the required strength of the branch joint. That is, when the strength of the branch joint is not so required, the former is selected, and when the strength is required, the latter is selected.

  A branch pipe connection method using another branch joint of the present invention is the same as that in the branch joint described above.

  Regardless of which branch joint described above is used, after the branch pipe is connected, the airtightness is ensured by the ring-shaped packing 8 made of rubber or the like inserted between the periphery of the opening 4A of the branch section 4 and the main pipe 1. In order to further improve the airtightness, a sealing member is interposed between the branching sleeve piece 2 and the pressing sleeve piece 5, as shown in FIG. That is, the belt-like seal member 10A as shown in FIG. 9A is arranged inside the both ends of the branch sleeve piece 2 as shown in FIG. 9B, and as shown in FIG. The square ring-shaped sealing member 10B is disposed on the inner surface of the pressing sleeve piece 5 as shown in FIG. At this time, a belt-like pressing member 10C as shown in FIG. 5C is sandwiched between both ends in the width direction of the square ring-shaped sealing member 10B and the pressing sleeve piece 5. The band-shaped seal member 10A and the square ring-shaped seal member 10B are made of, for example, soft rubber such as butyl rubber, and the band-shaped pressing member 10C is formed by covering sponge rubber with butyl rubber as shown in FIG.

  A state in which the belt-like seal member 10A, the square ring-like seal member 10B, and the belt-like presser member 10C are arranged is shown in FIGS. When the branch sleeve piece 2 and the pressing sleeve piece 5 are fastened in this state, the fastening flanges 2B and 5B of the sleeve pieces 2 and 5 approach each other. As a result, the belt-like seal member 10A and the square ring-like seal member The end portions of 10B are pressed and integrated. On the other hand, since the pressing member 10C is harder than the sealing members 10A and 10B, the pressing member 10C does not deform so much, and as shown in FIG. 5G, the pressing member is interposed between the fastening flanges 2B and 5B of the sleeve pieces 2 and 5. 10C is placed. As a result, the sealing members 10A and 10B can be prevented from being pushed outward by fastening.

  The branching sleeve piece 2 and the pressing sleeve piece 5 may be other metals such as iron in addition to cast iron.

  As described above, according to the present invention, by forming the main rib on the outer surface of the pressing sleeve piece, the inner diameter of the branch joint does not match the outer diameter of the main pipe, and the strength of the main pipe is weak. Even in this case, the pressing protrusion of the pressing sleeve piece and the outer surface of the main pipe can be brought into surface contact, so that the branch pipe can be reliably connected to the main pipe such as a gas pipe. Even when a branch pipe is connected to a weak main pipe, it is possible to reliably prevent the main pipe from being adversely affected by bending stress that acts locally on the main pipe. Moreover, by forming the main rib on the outer surface other than the end portion of the pressing sleeve piece, when the pressing sleeve piece is fastened, the reduced diameter stress can be applied uniformly to the end portion of the pressing sleeve piece. An adverse effect on the pressing sleeve piece due to the concentration of the reduced diameter stress can be reliably prevented.

It is the perspective view which looked at the joint for branch of this invention with which the main pipe was mounted | worn from the upper direction. It is the perspective view which looked at the joint for branch of this invention with which the main pipe was mounted | worn from the downward direction. It is the sectional view on the AA line of FIG. It is the BB sectional view taken on the line of FIG. It is sectional drawing which shows the contact of a main pipe and a pressing protrusion, (A) shows the case where a main pipe and a pressing protrusion are in point contact, (B) shows a main pipe and a pressing protrusion. Shows the case of surface contact. It is the perspective view which looked at the other joint for branching of this invention with which the main pipe was mounted | worn from the upper direction. It is the perspective view which looked at the joint for other branches of this invention from the downward direction. It is CC sectional view taken on the line of FIG. It is a figure which shows arrangement | positioning of a sealing member and a pressing member. It is a fragmentary sectional view which shows the state which connected the branch pipe to the main pipe with the coupling for branch conventionally. It is a bottom view which shows the sleeve piece for branch parts of the conventional joint for branches. It is a bottom view which shows the sleeve piece for a press of the joint for branch conventionally.

Explanation of symbols

1: Main pipe 1A: Hole 2: Branching sleeve piece 2A: Supporting protrusion 2B: Fastening flange 2C: Bolt hole 3: Branching pipe 4: Branching part 4A: Opening 5: Pressing sleeve piece 5A: Pressing Projection 5B: Fastening flange 5C: Bolt hole 5D: Reinforcing flange 5E: Sub rib 6: Bolt 7: Nut 8: Packing 9: Main rib 9A: Groove 10A: Strip-shaped seal member 10B: Square ring-shaped seal member 10C: Holding member 11: Main pipe 11A: Hole 12: Branching sleeve piece 12A: Protrusion protrusion 12B: Fastening flange 12C: Bolt hole 13: Pressing sleeve piece 13A: Pressing protrusion 13B: Fastening flange 13C: Bolt hole 14: Branch portion 14A: Opening 15: Packing 16: Bolt 17: Nut 18: Branch pipe

Claims (10)

In the branch joint for connecting the branch pipe in the middle of the main pipe,
A semi-cylindrical branch sleeve piece formed with a branch portion to which the branch pipe is connected; and a semi-cylindrical pressing sleeve piece fastened to the branch sleeve piece; A fulcrum projection that contacts the outer surface of the main pipe is formed on the inner surface of the branch sleeve piece in the vicinity, and the fulcrum projection contacts the inner surfaces of both ends of the pressing sleeve piece. A pressing projection that contacts the outer surface of the main pipe outside the outer surface of the main pipe is formed, and a plurality of pressing protrusions are provided along the axial direction of the pressing sleeve piece on the outer surface other than both ends of the pressing sleeve piece. The main rib is formed with a branch joint.   2. The branching according to claim 1, wherein thicknesses of both end portions of the pressing sleeve piece are formed so as to decrease from a circumferential end portion to a circumferential central portion of the pressing sleeve piece. Fittings.   The branch joint according to claim 1, wherein reinforcing flanges are formed on outer surfaces of both end portions of the pressing sleeve piece. 4. The branch joint according to claim 3, wherein a sub-rib is formed in a circumferential direction central portion of the reinforcing flange from a surface on the main rib side toward an end portion of the main rib . On both inner peripheral surfaces of the pressing sleeve piece, inclined surfaces are formed inward from each other on the inner side of the pressing projection, and the inclined surfaces are formed by the branching sleeve piece and the branching sleeve piece. When the main pipe is deformed with the fulcrum protrusion as a fulcrum by the pressing force of the pressing protrusion, the main pipe and the pressing sleeve are in close contact with each other. The joint for branching according to any one of claims 1 to 4, wherein a contact area with the piece is increased .   The said main rib is formed in parallel with the outer surface of the said sleeve piece for a press corresponding to between the said inclined surfaces of the both ends of the said sleeve piece for a press, The any one of Claim 1 to 5 characterized by the above-mentioned. The branch joint described in 1.   The branch according to any one of claims 1 to 6, wherein the height of the end portion of the main rib is continuously reduced toward the end portion of the pressing sleeve piece. Fittings.   The seal member is interposed between the branch sleeve piece and the pressing sleeve piece, and the seal member is pushed outward when the branch sleeve piece and the pressing sleeve piece are fastened together. The branch joint according to any one of claims 1 to 7, further comprising a presser member to prevent.   The branch joint according to claim 8, wherein the seal member is made of soft rubber.   The branch joint according to any one of claims 1 to 9, wherein the branch sleeve piece and the pressing sleeve piece are made of cast iron.

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