JP2009221823A - Connector of reinforcing bar - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connector of a reinforcing bar, increasing the connecting force by preventing rotation of a cylindrical body. <P>SOLUTION: This connector 1 of the reinforcing bar includes a cylindrical body 2 and a wedge member 3, which have an elliptic section. In the cylindrical body 2, the ends 5a, 5b of the reinforcing bar can be inserted from openings 6a, 6b at both ends so that two reinforcing bars 4a, 4b are disposed in series on the same straight line. The cylindrical body 2 includes: a pair of tabular wall parts 8, 8; a half cylindrical wall part 7 connecting the tabular wall parts to each other on one side; and a pair of bent parts 10, 10 provided on the other side, wherein the paired tabular wall parts 8, 8 are provided with wedge penetrating holes 9a, 9a and wedge penetrating holes 9b, 9b. The paired bent parts 10, 10 are extended from the tabular wall parts 8, 8, and welded and fixed to each other in the mutually abutting state on the outer peripheral surfaces thereof, thereby constituting an inward projecting part 11 extended along the axial direction of the member of the cylindrical body 2 and projected from the inner surface of the cylindrical body 2 toward the inside of the cylindrical body. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a reinforcing bar joint applied when joining reinforcing bars.

  Reinforcing bars are usually processed to a predetermined length in consideration of the workability at the time of bar arrangement, so on-site joining work is indispensable, but as a means of joining such reinforcing bars, the cross section is oblong. There is known a method of joining two reinforcing bars through a joining tool made of a steel tubular body and a wedge member.

  According to such a connector, by inserting the two reinforcing bar ends from the opposite directions into the cylindrical body, and then driving the wedge member between the two reinforcing bars from the wedge insertion hole provided in the cylindrical body, Reinforcing bars can be joined to each other (see Patent Document 1 and Non-Patent Document 1).

  However, in the case of a joining tool composed of a steel cylinder and a wedge member having an oval cross section, the two reinforcing bar ends are inserted alternately into the oval cylinder, so that at the joint location. A deviation along the direction perpendicular to the material axis of the reinforcing bar occurs between the two reinforcing bars.

  For this reason, it is impossible to join reinforcing bars along the same straight line, and in Japan, where seismic standards are strict and the amount of reinforcing bars tends to be large, regardless of the bar arrangement pitch being sufficiently larger than the reinforcing bar diameter, the prescribed clearance is required. It is difficult to arrange the bars as designed while securing the cover.

  In addition, when a tensile force acts on the two reinforcing bars, the cylinder rotates due to the above-described deviation in the direction perpendicular to the material axis, and the engagement between the reinforcing bars and the wedge member becomes loose, and the cylinder rotates. Accordingly, a bending moment is generated in the reinforcing bar, and there is a concern that the reinforcing bar breaks with a smaller tensile load than when only the tensile force acts.

Japanese Utility Model Publication No. 58-32498

ERICO International Corporation, [Search August 2, 2006], Internet <URL: http://www.erico.com/products/QuickWedge.asp>

  Under such circumstances, the present applicant has succeeded in developing a reinforcing bar joint that can prevent the rotation of the cylinder and increase the joining force.

  This connector has a cylindrical body with an oval cross-sectional shape in which the ends of each reinforcing bar can be inserted from the openings at both ends so that the two reinforcing bars are arranged in series on the same straight line, and each reinforcing bar Load transmission rods inserted into the cylinder so that the ends of the cylinders are in parallel with the ends of the cylinder and wedges formed at opposing positions of the pair of flat wall portions constituting the cylinder The wedge member is inserted into the insertion hole, and the wedge member is driven between the first reinforcing member and the load transmission rod, and the first reinforcing member and the load transmission rod. It is comprised with the 2nd wedge member.

  According to such a reinforcing bar joint, by newly introducing the load transmission rod, it becomes possible to reliably transmit the tensile load even in a state where the two reinforcing bars are arranged in series on the same straight line, thus, The tensile strength of the reinforcing bars can be sufficiently exhibited while preventing the rotation of the cylinder.

  However, as the number of parts increases, the cost increases, so the main application range is a structure or a part that requires high quality, and there is room for separately developing a connector with excellent economic efficiency.

  The present invention has been made in consideration of the above-described circumstances, and an object of the present invention is to provide a reinforcing bar joint that can increase the joining force by preventing the rotation of a cylindrical body and is excellent in economy. To do.

  In order to achieve the above-described object, the reinforcing bar joint according to the present invention, as described in claim 1, is configured so that the ends of the reinforcing bars are arranged at both ends so that the two reinforcing bars are arranged in series on the same straight line. Each of which has an oval cross-sectional shape that can be inserted through each of the openings, and a wedge member that is inserted into a wedge insertion hole that is formed at a position opposite to the pair of flat plate wall portions that constitute the cylindrical body. In addition, an inward projecting portion projecting from the inner surface of the cylindrical body toward the inside of the cylindrical body extends along the material axis direction of the cylindrical body, and the wedge member includes the two reinforcing bars. The first wedge member driven between one reinforcing bar and the inner projecting portion and the second wedge member driven between the other reinforcing bar and the inner projecting portion. Is.

  Further, the reinforcing bar joint according to the present invention is formed by bending a rectangular steel plate into a cylindrical shape to form the cylindrical body, and a pair of bent portions formed on both sides of the rectangular steel plate are arranged on the outer peripheral surface thereof. The inward protruding portions are formed by abutting each other and projecting inward.

  Further, the reinforcing bar joint according to the present invention is formed by bending a rectangular steel plate into a cylindrical shape to form the cylindrical body, and one of the pair of edges located on both sides of the rectangular steel plate. And forming an inwardly bent portion at the other edge and engaging the inwardly bent portion with an outer recess formed behind the inwardly protruding portion. It is a thing.

  In the reinforcing bar joint according to the present invention, the cylindrical body is configured so that the cross-sectional shape thereof is a closed cross section, and a part of the cylindrical body is bent inward to form the inner part. This is a method in which a direction projecting portion is formed.

  Further, the reinforcing bar joint according to the present invention is configured so that the cylindrical body is configured so that a cross-sectional shape thereof is a closed cross section, and a part of the cylindrical body is formed into a thick cross section. A projecting portion is formed.

  As described above, the present applicant has succeeded in developing a new reinforcing bar joint to prevent the rotation of the cylinder and increase the joining force. And, according to such a reinforcing bar joint, it is possible to reliably transmit a tensile load even when two reinforcing bars are arranged in series on the same straight line by introducing a load transmission rod.

  However, in such a connector, since a load transmission rod is essential, the number of parts is increased as compared with the conventional connector. The present applicant has studied whether or not two reinforcing bars can be joined to each other in a state of being arranged in series on the same straight line without increasing the number of parts. A new connector has been newly developed that can firmly bond two reinforcing bars in the above-described bonding configuration.

  That is, in the reinforcing bar joint according to the present invention, the inward projecting portions projecting from the inner surface of the cylinder toward the inside of the cylinder extend along the material axis direction of the cylinder, and both ends of the cylinder Of the two reinforcing bars inserted from the opening, the first wedge member is driven between one reinforcing bar and the inner projecting portion, and the second between the other reinforcing bar and the inner projecting portion. The wedge member is driven.

  In this way, when a tensile load acts on the two reinforcing bars, the tensile load is transmitted from one reinforcing bar to the inward protruding portion via the first wedge member, and further, the inward protruding portion To the other rebar through the second wedge member.

  Here, the first wedge member is not easily inserted into one of the reinforcing bars and the inward protruding portion, and the second wedge member is not easily inserted into the other reinforcing bar and the inward protruding portion. It extends along the material axis direction and exhibits high rigidity against in-plane bending including the material axis.

  Accordingly, a sufficient amount of the first and second wedge members are inserted into the reinforcing bars, and when a tensile load is applied to the two reinforcing bars, the reinforcing bars are prevented from coming out. That is, it can be said that the inward projecting portion according to the present invention is integrally formed with the cylindrical body as an alternative to the above-described load transmission rod.

  Since the two reinforcing bars are arranged in series on the same straight line, the tensile load from each reinforcing bar acts on the cylinder on the same line of action, and therefore the cylinder rotates as in the prior art. There is no fear.

  The inward projecting portion is optional as long as it protrudes from the inner surface toward the inside of the cylinder and extends along the material axis direction of the cylinder, for example, a rectangular steel plate The cylindrical body may be formed by bending into a cylindrical shape, and a pair of edges located on both sides of the rectangular steel plate may be brought into contact with each other on their outer peripheral surfaces and protrude inward.

  Further, the rectangular steel plate is bent into a cylindrical shape to form the cylindrical body, and an inward projecting portion is formed on one edge of the pair of edges located on both sides of the rectangular steel plate. Alternatively, an inner bent portion may be formed on the other edge portion, and the inner bent portion may be engaged with an outer concave portion formed behind the inner projecting portion.

  Further, the cylindrical body is configured so that its cross-sectional shape is a closed cross section, and a part of the cylindrical body is bent inward, or a part of the cylindrical body is formed into a thick cross section. You may make it form a direction protrusion part.

  In addition, the closed cross section in the present invention refers to a cross section represented by a cylindrical cross section or an oval cross section having no open portion, and a case where the angle of a tangent along the circumferential direction changes continuously. When the change in the tangent angle is discontinuous, for example, it does not include the case where the change in the tangential angle becomes discontinuous at the contact position as in the two bent portions according to claim 2. .

  Embodiments of a reinforcing bar connector according to the present invention will be described below with reference to the accompanying drawings. Note that components that are substantially the same as those of the prior art are assigned the same reference numerals, and descriptions thereof are omitted.

  FIG. 1 is a view showing a reinforcing bar joint according to the present embodiment. As can be seen from the figure, the reinforcing bar joint 1 according to the present embodiment includes a cylindrical body 2 and a wedge member 3 having an oval cross-sectional shape.

  The cylindrical body 2 has openings 6a and 6b at both ends, and end portions of the two reinforcing bars so that the two reinforcing bars 4a and 4b to be joined are arranged in series on the same straight line. 5a and 5b can be inserted from the openings 6a and 6b at both ends.

  The cylindrical body 2 includes a pair of flat wall portions 8 and 8 arranged to face each other at a predetermined separation distance, a semi-cylindrical wall portion 7 that connects the flat wall portions to each other on one side, and the other side. The pair of flat wall portions 8 and 8 are formed with wedge insertion holes 9a and 9a so as to face each other, and the same wedge insertion. The holes 9b, 9b are formed so as to face each other at positions away from the wedge insertion holes 9a, 9a along the material axis direction of the cylindrical body 2.

  The pair of bent portions 10, 10 extend from the flat wall portions 8, 8, respectively, and are welded and fixed in a state where they are in contact with each other on their outer peripheral surfaces, thereby along the material axis direction of the cylindrical body 2. The inner projecting portion 11 extends from the inner surface of the cylindrical body 2 and extends toward the inner side of the cylindrical body.

  As will be described later, since the wedge member 3 needs to bite into the inner projecting portion 11 when the wedge member 3 is driven, the projection height of the inner projecting portion 11 is set in advance in the wedge insertion hole. Set it on the position.

  In manufacturing such a cylindrical body 2, a rectangular steel plate is bent into a cylindrical shape, bent portions 10 and 10 are formed on both sides of the rectangular steel plate, and then brought into contact with each other on the outer peripheral surface of the bent portion. Can be fixed by welding.

  The wedge member 3 includes a wedge member 3a as a first wedge member that is driven between the end portion 5a of the reinforcing bar 4a, which is one of the two reinforcing bars 4a and 4b, and the inward protruding portion 11. The other reinforcing bar is a wedge member 3b as a second wedge member driven between the end 5b of the reinforcing bar 4b and the inwardly projecting portion 11, and the wedge member 3a is an end 5a of the reinforcing bar 4a. The wedge member 3b is inserted between the end portion 5b of the reinforcing bar 4b and the inward protruding portion 11 and is inserted into the wedge insertion holes 9a, 9a formed between the inner protruding portion 11 and the inner protruding portion 11. It is inserted through the insertion holes 9b, 9b.

  When the wedge member 3a is driven between the end portion 5a of the reinforcing bar 4a and the inwardly projecting portion 11, the wedge member 3a takes the reaction force from the semi-cylindrical wall portion 7 of the cylindrical body 2 and the inner portion 5a. The projecting portions 11 are engaged with each other. Similarly, when the wedge member 3b is driven between the end portion 5b of the reinforcing bar 4b and the inward projecting portion 11, the wedge member 3b is engaged with the end portion 5b and the inward projecting portion 11 with each other.

  In order to join the reinforcing bars 4 a and 4 b using the reinforcing bar joint 1 according to the present embodiment, first, the end 5 a of the reinforcing bar 4 a is inserted from one opening 6 a of the cylindrical body 2 and the other end of the cylindrical body 2. The end 5b of the reinforcing bar 4b is inserted from the opening 6b.

  Next, the wedge member 3a is passed through the wedge insertion hole 9a to press-fit it, and the wedge member 3b is passed through the wedge insertion hole 9b to press-fit it. In press-fitting, a conventionally known wedge driving machine may be appropriately selected and used.

  FIG. 2 is a view showing a state where the joining of the reinforcing bars 4a and 4b is completed after the wedge driving operation is completed.

  In the reinforcing bar joint 1 according to the present embodiment, an inwardly projecting portion 11 that protrudes from the inner surface of the tubular body toward the inside of the tubular body 2 extends along the material axis direction of the tubular body 2. Yes, when the two wedge members 3a and 3b are press-fitted, the wedge member 3a is press-fitted between the end portion 5a of the reinforcing bar 4a and the inwardly protruding portion 11, and the end portion 5b of the reinforcing bar 4b is protruded inwardly. The wedge member 3b is press-fitted between the portions 11.

  In this way, when a tensile load is applied to the two reinforcing bars 4a and 4b, the tensile load is transmitted from the reinforcing bar 4a to the inward projecting portion 11 via the wedge member 3a, and further inwardly projecting. It is transmitted from the part 11 to the reinforcing bar 4b through the wedge member 3b.

  Since the two reinforcing bars 4a and 4b are arranged in series on the same straight line, the tensile load from each reinforcing bar 4a and 4b acts on the cylinder 2 on the same line of action.

  As described above, according to the reinforcing bar joint 1 according to the present embodiment, the wedge member 3a is provided between the end portion 5a of the reinforcing bar 4a inserted from the opening 6a of the cylindrical body 2 and the inward protruding portion 11. And the wedge member 3b is driven between the end portion 5b of the reinforcing bar 4b inserted from the opening 6b and the inwardly protruding portion 11, so that a tensile load acts on the two reinforcing bars 4a and 4b. At this time, the tensile load is transmitted from the reinforcing bar 4a to the inward protruding portion 11 via the wedge member 3a, and further transmitted from the inward protruding portion 11 to the reinforcing bar 4b via the wedge member 3b.

  Therefore, the tensile load from each reinforcing bar 4a, 4b acts on the cylindrical body 2 on the same line of action, and there is no fear that the cylindrical body 2 will rotate, and the bending associated with the rotation of the cylindrical body 2 will cause the reinforcing bar 4a, Since it does not add to 4b, there is no possibility that the reinforcing bars 4a and 4b will not break due to tension and bending in a state where the tensile strengths of the reinforcing bars 4a and 4b are not exerted, and the tensile strength of the reinforcing bars 4a and 4b can be sufficiently exerted. It becomes.

  In addition, the wedge member 3a is difficult to insert into the reinforcing bar 4a and the inward protruding portion 11, and the wedge member 3b is difficult to insert into the reinforcing bar 4b and the inward protruding portion 11, but the inner protruding portion 11 is in the material axis direction of the cylindrical body 2. It exhibits high rigidity against in-plane bending including the material axis.

  Accordingly, a sufficient amount of the wedge members 3a and 3b is inserted into the reinforcing bars 4a and 4b, and when a tensile load is applied to the reinforcing bars 4a and 4b, the reinforcing bars 4a and 4b are reliably prevented from coming out.

  Further, according to the reinforcing bar joint 1 according to the present embodiment, the inner projecting portion 11 is integrally formed with the cylindrical body 2 as an alternative to the load transmitting rod as described above, so that the load transmitting rod is unnecessary. As a result, the number of parts can be reduced, resulting in a more economical connector.

  In this embodiment, as can be seen well in FIG. 2, the inner projecting portion 11 is configured such that the tip line thereof is parallel to the material axis direction of the cylindrical body 2, but the inner projecting portion has such a configuration. It is not limited.

FIG. 3 shows a reinforcing bar joint 1a according to a modification. In connectors 1a according to a modification as shown in the diagram (a), instead of the inwardly projecting portion 11, the opening side of the collision near the open ends 6a, 6b than the projecting height h ₁ at the center An inward projecting portion 31 having a height h ₂ is provided.

  According to such a modified example, even if the reinforcing bars 4a and 4b are subjected to a bending deformation at the driving position by the driving of the wedge members 3a and 3b, the reinforcing bars 4a and 4b are as shown in FIG. The end portions 5a and 5b receive reaction force from the inwardly projecting portion 31 at the contact points 32a and 32b, and the rotational deformation in the direction indicated by the arrow in FIG. Therefore, it becomes possible to suppress the bending of the reinforcing bars 4a and 4b.

  Further, in the present embodiment, the rectangular steel plate is bent into a cylindrical shape to form the cylindrical body 2, and the bent portions 10 and 10 are formed on both sides of the rectangular steel plate, respectively, and the outer peripheral surface of the bent portion is Although the inward projecting portion 11 is configured by being fixed in a state of being in contact with each other and projecting inward, the inward projecting portion according to the present invention is not limited to such a configuration.

  FIG. 4 shows a reinforcing bar joint 41 composed of a cylindrical body 2 a having an oval cross-sectional shape and a wedge member 3, and the cylindrical body 2 a has openings 6 a and 6 b at both ends, similarly to the cylindrical body 2. The two reinforcing bars 4a and 4b to be joined can be inserted through the openings 6a and 6b at both ends so that the two reinforcing bars 4a and 4b are arranged in series on the same straight line. A pair of flat wall portions 8 and 8 which are arranged to face each other at a predetermined separation distance, and a semi-cylindrical wall portion 7 which connects the flat wall portions to each other on one side. The pair of flat wall portions 8 and 8 are formed with wedge insertion holes 9a and 9a so as to face each other, and the same wedge insertion holes 9b and 9b are provided in the direction of the material axis of the cylindrical body 2. Along the wedge insertion holes 9a, 9a so as to face each other.

  On the other hand, in this modification, an inward protruding portion 42 and an inward bent portion 43 are respectively extended on the other side of the flat wall portions 8, 8. An inward bent portion 43 is engaged with an outer concave portion 44 formed at the back.

  In manufacturing the cylindrical body 2a, a rectangular steel plate is bent into a cylindrical shape, and an inward projecting portion 42 is formed on one edge of a pair of edges located on both sides of the rectangular steel plate. In addition, the inner bent portion 43 may be formed on the other edge, and the inner bent portion 43 may be engaged with the outer concave portion 44 formed behind the inner projecting portion 42.

  Since the configuration and operational effects are substantially the same as those of the above-described embodiment except that the inner projecting portion 42 is employed instead of the inner projecting portion 11, the description thereof is omitted here.

  FIG. 5A is a diagram showing another modification. A reinforcing bar connector 51 according to the modification includes a cylindrical body 2b having an oval cross section and a wedge member 3. The cylindrical body 2b has openings 6a and 6b at both ends, like the cylindrical body 2. The two rebars 4a and 4b to be joined are configured so that the ends 5a and 5b of the two rebars can be inserted from the openings 6a and 6b at both ends so that the two rebars 4a and 4b are arranged in series on the same straight line. And a pair of flat wall portions 8 and 8 arranged to face each other at a predetermined distance, and a semi-cylindrical wall portion 7 that connects the flat wall portions to each other on one side. The plate-like wall portions 8 and 8 are formed with wedge insertion holes 9a and 9a so as to face each other, and the same wedge insertion holes 9b and 9b are provided along the material axis direction of the cylindrical body 2b. It forms so that it may mutually oppose in the position away from the insertion holes 9a and 9a.

  On the other hand, in the present modification, the cylindrical body 2b is configured such that the cross-sectional shape thereof is a closed cross section, and a part of the cylindrical body is bent inward, whereby the cylindrical body 2b. An inward protruding portion 52 that protrudes from the inner surface of the cylindrical body toward the inner side of the cylindrical body 2b extends along the material axis direction of the cylindrical body 2b. 8 on the other side.

  Since the configuration and the operational effects are substantially the same as those of the above-described embodiment except that the inner projecting portion 52 is employed instead of the inner projecting portion 11, the description thereof is omitted here.

  FIG. 5B is a diagram showing still another modification. The reinforcing bar connector 53 according to the modification includes a cylindrical body 2c having an oval cross section and a wedge member 3. The cylindrical body 2c has openings 6a and 6b at both ends, like the cylindrical body 2. The two rebars 4a and 4b to be joined are configured so that the ends 5a and 5b of the two rebars can be inserted from the openings 6a and 6b at both ends so that the two rebars 4a and 4b are arranged in series on the same straight line. And a pair of flat wall portions 8 and 8 arranged to face each other at a predetermined distance, and a semi-cylindrical wall portion 7 that connects the flat wall portions to each other on one side. The plate-like wall portions 8 and 8 are formed with wedge insertion holes 9a and 9a so as to face each other, and the same wedge insertion holes 9b and 9b are provided along the material axis direction of the cylindrical body 2c. It forms so that it may mutually oppose in the position away from the insertion holes 9a and 9a.

  On the other hand, in this modification, as shown in FIG. 5 (b), the cylindrical body 2c is configured such that its cross-sectional shape is a closed cross-section, and a part of the cylindrical body is formed into a thick section. Thus, an inward protruding portion 54 that protrudes from the inner surface of the cylindrical body toward the inside of the cylindrical body 2c extends along the material axis direction of the cylindrical body 2c, and the inward protruding portion is Each of the flat wall portions 8, 8 extends to the other side.

  Since the configuration and the operational effects are substantially the same as those of the above-described embodiment except that the inner projecting portion 54 is employed instead of the inner projecting portion 11, the description thereof is omitted here.

It is a figure of the reinforcing bar joint 1 concerning this embodiment, (a) is a side view, (b) is an arrow line view from the AA line direction. It is the figure which showed a mode that the reinforcing bars 4a and 4b were joined using the joining tool 1, (a) is sectional drawing, (b) is sectional drawing which follows a BB line. It is the figure of the reinforcing bar joint 1a which concerns on a modification, (a) is a side view, (b) is explanatory drawing which showed the effect | action. It is the figure of the reinforcing bar joint 41 which concerns on a modification, (a) is a side view, (b) is an arrow line view from CC line direction. It is the figure which showed the reinforcing-bar joint tool which concerns on a modification, (a) is a side view of the joint tool 51, (b) is a side view of the joint tool 53.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reinforcing bar joint 2 Cylindrical body 3 Wedge member 3a First wedge member 3b Second wedge member 4a, 4b Reinforcing bar 5a, 5b Reinforcing bar ends 6a, 6b Open both ends 7 Semicircular wall 8 Flat plate wall 9a, 9b Wedge insertion hole 10 Bending portion 11 Inward protruding portions 1a, 41, 51 Reinforcing bar joints 31, 42, 52, 54 Inward protruding portion 43 Inward bent portion

Claims (5)

A cylindrical body having an oval cross-sectional shape in which the ends of each reinforcing bar can be inserted from the openings at both ends so that the two reinforcing bars are arranged in series on the same straight line, and a pair constituting the cylindrical body A wedge member inserted through a wedge insertion hole formed at a position opposed to the flat plate wall portion, and an inward projecting portion projecting from the inner surface of the cylindrical body toward the inner side of the cylindrical body. The wedge member extends along the material axis direction of the cylindrical body, and the wedge member includes a first wedge member that is driven between one of the two reinforcing bars and the inward protruding portion. A reinforcing bar joint comprising a second wedge member driven between the other reinforcing bar and the inward projecting portion. A rectangular steel plate is bent into a cylindrical shape to form the cylindrical body, bent portions are formed on both sides of the rectangular steel plate, are brought into contact with each other on the outer peripheral surface of the bent portion, and protrude inward. The reinforcing bar joint according to claim 1, wherein the inward projecting portion is formed by being fixed in a bent state. Forming the cylindrical body by bending a rectangular steel plate into a cylindrical shape, of the pair of edges located on both sides of the rectangular steel plate, forming the inner projecting portion on one edge, The reinforcing bar joint according to claim 1, wherein an inner bent portion is formed on the other edge portion, and the inner bent portion is engaged with an outer concave portion formed behind the inner projecting portion. 2. The inward projecting portion according to claim 1, wherein the cylindrical body is configured such that a cross-sectional shape thereof is a closed cross section, and the inner projecting portion is formed by forming a cross-section in which a part of the cylindrical body is bent inward. Reinforcing bar joint. The reinforcing bar according to claim 1, wherein the cylindrical body is configured such that a cross-sectional shape thereof is a closed cross section, and the inner projecting portion is formed by forming a cross section in which a part of the cylindrical body is formed thick. Joints.

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