Connecting member

Abstract

The present invention provides a connecting member that prevents the movable piece from easily falling out of the hollow cross-section member insertion part during removal or installation. [Solution] The plug 1 has an elongated hole 11 in a cylindrical hollow cross-section member insertion part 10 that is inserted into the hollow cross-section member 4, and the movable piece 2 is housed inside the hollow cross-section member insertion part 10, and the side portion 21 of the movable piece 2 is provided with a projection 20 that is restricted in the direction of movement of the fastening member 3 by the elongated hole 11, and the plug 1 and the movable piece 2 are fastened together by the fastening member 3, and as the movable piece 2 moves, the diameter of the hollow cross-section member insertion part 10 expands and it can freely press against the inner wall 40 of the hollow cross-section member 4, and even when the fastening member 3 is fastened or unfastened, the movable piece 2 remains inside the hollow cross-section member insertion part 10 without falling out.

Description

Technical Field

[0001] This invention relates to a connecting member for connecting hollow cross-sectional members such as synthetic resin-coated and adhered steel pipes. More specifically, it belongs to the technical field of a connecting member for pressing the inside of a hollow cross-sectional member to connect the hollow cross-sectional members.

Background Art

[0002] Conventionally, a connector described in Patent Document 1 developed by the applicant is known. That is, although FIG. 13 of Document 1 is easy to understand, in the cylindrical portion 56 of the main body 57, a frustum-conical moving piece 63 formed on the outer peripheral surface with a tapered surface 62 corresponding to the tapered surface 61 of the cylindrical portion 56 is fitted so as to be movable in the axial direction of the main body 57. On the tapered surface 62 of the moving piece 63, a plurality of anti-rotation ridges 64 in the axial direction that engage with the slit 60 of the cylindrical portion 56 are provided to prevent the moving piece 63 from rotating around its own axis. Further, a threaded hole 65 is provided through the axial center portion of the moving piece 63, and a threaded portion of a single hexagonal socket bolt 67 with a nominal diameter of 6 mm that is inserted into a bolt through-hole 66 provided through the axial center portion of the main body 57 and fastens the moving piece 63 and the second fitting portion 58 of the main body 57 can be screwed into the threaded hole 65.

[0003] Furthermore, Patent Document 2 by the present applicant describes a plug comprising a disc-shaped base, a bottomed cylindrical first insertion portion coaxially connected to one surface of the base and having multiple slits and tapered in shape with an inner diameter that widens as it approaches the opening end, and a bottomed cylindrical second insertion portion coaxially connected to the other surface of the base and having a circumferential groove on its outer circumference, and a truncated cone shape having axial protrusions on the outer surface that engage with the taper of the first insertion portion of the plug, with the protrusions engaging with the slits. The plug consists of an expanding nut fitted into the first insertion portion and a bolt inserted through a through-hole in the shaft of the plug and screwed into the threaded hole in the shaft of the expanding nut. The plug and the steel pipe are joined by tightening the bolt with the first insertion portion of the plug fitted into one of the materials to be connected, the plug and the steel pipe are joined, the second insertion portion of the plug is fitted into the other material to be connected, an L-shaped joint, and a set screw screwed from the joint engages with the circumferential groove of the second insertion portion to connect two tubular materials to be connected. The expanding nut is fitted into the first insertion portion of the plug so as to be movable only in the axial direction, and as the bolt is tightened it approaches the base and the outer diameter of the first insertion portion of the plug expands. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2002-310111 [Patent Document 2] Design Registration No. 1149496 Gazette [Overview of the project] [Problems that the invention aims to solve]

[0005] The connecting members described in Patent Documents 1 and 2 have a drawback: when inserting a bolt for installation, the movable piece (expanding nut) is pushed out, causing it to fall off. This not only makes installation time cumbersome but also increases the risk of losing the movable piece. If one tries to change the orientation so that the movable piece is facing upwards to prevent it from falling off, the orientation must be changed each time it is installed, resulting in unnecessary movement. Furthermore, if one attempts to insert the movable piece deeply into the main body beforehand to prevent it from falling out, the wedge effect causes the cylindrical part to expand in diameter, resulting in problems such as being unable to insert it into the steel pipe of the material to be connected. When removing the component, if the bolt is completely removed, there is nothing to support the movable component, and it will fall off the main body. Not only is it time-consuming to find, but if it falls inside the pipe, it is difficult to pick up. If it is just a pipe, it is not difficult as the movable component can be dropped by simply tilting it vertically downwards, but if it is part of a structure, unnecessary work must be done, such as tilting the entire structure vertically downwards to drop the movable component, or removing the other part as well, and these are issues that need to be resolved.

[0006] Therefore, the object of the present invention is to provide a connecting member that prevents the movable piece from easily falling out of the hollow cross-section member insertion part during removal or installation, thereby reducing the time required for removal and installation and preventing the loss of the movable piece. [Means for solving the problem]

[0007] As a means of solving the above problems, the invention described in claim 1 is a connecting member comprising a plug 1 inserted into and connected to a hollow cross-sectional member 4, a movable piece 2, and a fastening member 3, The plug 1 has an elongated hole 11 in the cylindrical hollow cross-section member insertion portion 10 that is inserted into the hollow cross-section member 4. The movable piece 2 is housed within the hollow cross-sectional member insertion portion 10, and the side portion 21 of the movable piece 2 is provided with a projection 20 that restricts the movement direction of the fastening member 3 by the elongated hole 11. The plug 1 and the movable piece 2 are fastened together by the fastening member 3, and as the movable piece 2 moves, the hollow cross-sectional member insertion portion 10 expands in diameter, allowing it to press against the inner wall 40 of the hollow cross-sectional member 4. The connecting member is characterized in that even when the fastening member 3 is fastened or unfastened, the movable piece 2 remains in place without falling out of the hollow cross section member insertion portion 10.

[0008] The invention described in claim 2 is such that the movable piece 2 is capable of accommodating a portion of the fastening member 3 and consists of a plurality of divided bodies 2A, 2B having opposing surfaces 23 on which accommodating grooves 22 that contact the fastening member 3 are formed. In the connected state in which the plurality of divided bodies 2A and 2B are joined so that their opposing surfaces 23 are in contact with each other, the receiving grooves 22 of the plurality of divided bodies 2A and 2B define a fastening receiving space 24 that contacts a part of the fastening member 3. The connecting member according to claim 1, characterized in that it is configured to accommodate a portion of the fastening member 3 in the fastening accommodation space 24.

[0009] The invention described in claim 3 is a connecting member according to claim 1, characterized in that the hollow cross-sectional member insertion portion 10 of the plug 1 has a slit 13 formed in the axial direction together with the elongated hole 11, with the end portion 12 on the movable piece insertion side being open, or the slit 13 is formed in place of the elongated hole 11.

[0010] The invention described in claim 4 is a connecting member according to claim 1, characterized in that a slit 11a with a width narrower than the width of the protrusion 20 is formed in the axial direction at the end 12 on the movable piece insertion side of the elongated hole 11 provided in the hollow cross-sectional member insertion portion 10 of the plug 1.

[0011] The invention described in claim 5 is characterized in that a groove 42 is provided in the axial direction on the outer circumference 41 of the hollow cross-sectional member 4, A projection 50 is provided inside the joint 5 into which the hollow cross-sectional member 4 is inserted. The hollow cross-sectional member 4 can be inserted into the joint 5 by engaging the groove 42 and the projection 50. The connecting member according to claim 1, characterized in that the fastening member 3 is inserted into the joint 5 together with the plug 1, and the hollow cross section member insertion portion 10 of the plug 1 is inserted into the hollow cross section member 4, thereby enabling fastening of the plug 1 and the hollow cross section member 4.

[0012] The invention described in claim 6 is provided on the opposite side 14 of the movable piece insertion side 12 of the plug 1, an eccentric portion 16 is provided that is eccentric to the bolt insertion hole 16a into which the fastening member 3, which is a bolt 30, is inserted, and a projection 17 that protrudes in the axial direction is formed on the eccentric portion 16, A detachable attachment device 19, having a rod-shaped portion 18 that protrudes in the axial direction, is attached to the eccentric portion 16. The connecting member according to claim 1 is characterized in that, by fitting the joint 5 into which the hollow cross section member 4 is inserted and rotating it around the bolt insertion hole 16a into which the bolt 30 is inserted, the rod-shaped portion 18 of the attachment tool 19 passes over the protruding portion 17 of the plug 1, thereby emitting a sound, and the attachment tool 19 exerts a force that presses against the eccentric portion 16 and the inside of the joint 5, thereby enabling the joint 5 to be fixed in place.

[0013] The invention described in claim 7 is such that the hollow cross-sectional member 4 is a pipe, and the pipe 4 can be inserted into the hollow cross-sectional member insertion portion 10 of the plug 1 into which the movable piece 2 is inserted. The fastening member 3 consists of a bolt 30 and a nut 31. The bolt 30 and the nut 31 housed in the movable piece 2, which has an enlarged diameter and a roughly frustoconical shape, are fastened together, and the movable piece 2 is screwed forward, thereby expanding the diameter of the hollow cross-sectional member insertion portion 10, and enabling the hollow cross-sectional member insertion portion 10 to press against the inner wall 40 of the pipe 4. The connecting member according to claim 1 or 5 is characterized in that even when the bolt 30 and nut 31 are fastened or unfastened, the protrusion 20 provided on the movable piece 2 abuts against the end of the elongated hole 11 provided on the hollow cross section member insertion part 10, thereby preventing the movable piece 2 from falling out of the hollow cross section member insertion part 10. [Effects of the Invention]

[0014] According to the connecting member of the present invention, the movable piece no longer easily falls out of the hollow cross-section member insertion part during removal or installation, thereby reducing the time required for removal and installation, and preventing the loss of the movable piece. In addition, since the moving piece does not fall off even if the posture is not changed so that the moving piece faces upward, wasteful movement is suppressed. Furthermore, since the moving piece does not easily fall off even if it is not deeply housed in the insertion portion of the hollow cross-sectional member, the diameter expansion due to the wedge effect does not occur, and the hollow cross-sectional member can be inserted without difficulty, which is easy to use.

Brief Description of Drawings

[0015] [Figure 1] Front view (A), rear view (B), plan view (C), left side view (D) of A, and right side view (E) of A showing the connecting member of the present invention. [Figure 2] It is a perspective view of the connecting member. [Figure 3] (A) is an exploded view of the connecting member, and (B) is a perspective view showing different embodiments of the moving piece shown to the left of (A). [Figure 4] It is a cross-sectional view showing a second embodiment used for connecting linear pipes. [Figure 5] It is a cross-sectional view showing a third embodiment used for connecting pipes arranged in a T shape. [Figure 6] It is a fourth embodiment used for connecting pipes via an L-shaped joint, and (A) is a perspective view of the joint, (B) is an exploded view, and (C) is a completed view. [Figure 7] (A) to (D) are cross-sectional views showing the attachment procedure to the pipe with a partial notch in time series. [Figure 8] (A) to (C) are cross-sectional views showing the attachment procedure of the joint with a partial notch in time series. [Figure 9] It is a cross-sectional view showing a part of the connecting member with the joint attached.

Modes for Carrying Out the Invention

[0016] The connecting member of the present invention connects hollow cross-section members such as synthetic resin-coated adhesive steel pipes, and is used, for example, in the construction of the handle portion of a transport trolley. In addition to transport trolleys, it can also be used in fixed shelves, mobile shelves, and barricades for managing pedestrian flow. In the following embodiment, the hollow cross-sectional member 4 is shown as a pipe, but any hollow cross-sectional member may have a rectangular cross-section, and the plug 1 can be formed to match the cross-sectional shape (for example, if the hollow cross-sectional member has a rectangular cross-section, the plug 1 will also have a rectangular shape). Also, although the bolt 30 forming the fastening member 3 is shown as a countersunk bolt with a Phillips head, it is not limited to this, and for example, a bolt with a polygonal socket may also be used.

[0017] <First Example> The connecting members shown in Figures 1 to 3 will be explained in detail. This connecting member consists of a plug 1, a movable piece 2, and a fastening member 3. The plug 1 is formed in a cylindrical shape and has at least a hollow cross-sectional member insertion portion 10, and is preferably provided with an eccentric portion 16 as shown in the illustrated example. The hollow cross-section member insertion portion 10 of this plug 1 has an elongated hole 11 provided in the axial direction to prevent the movable piece 2 from falling out of the hollow cross-section member insertion portion 10. At the end 12 of the elongated hole 11 on the movable piece insertion side, a slit 11a is provided in the axial direction, which is narrower in width than the protrusion 20 of the movable piece 2, as described later. Because it is formed to be narrower than the protrusion 20 of the movable piece 2, the movable piece 2 will not easily fall out of the hollow cross-section member insertion portion 10. In the example shown in Figure 1, the hollow cross-sectional insertion portion 10 of the plug 1 is provided with one pair each of elongated holes 11 and slits 13 in an opposing arrangement. That is, the slits 13 are positioned 90° offset from the elongated holes 11. However, the number of elongated holes 11 and slits 13 may be increased or decreased, or the entire structure may consist only of elongated holes 11. (If there is only one elongated hole 11, there is a risk that the movable piece 2 may come loose.) Although it is possible to carry out the process without providing a cut 11a in the elongated hole 11, if a cut 11a is not provided, it is necessary to provide a slit 13. By providing the cuts 11a and slits 13 in the elongated hole 11 in this manner, the hollow cross-section member insertion portion 10 expands in diameter in conjunction with the protrusions 20 of the movable piece 2 positioned at that location.

[0018] The bolt insertion side 14 of the plug 1 (see Figures 1A and E) is provided with an eccentric portion 16 that is offset from the bolt insertion hole 16a which penetrates through the central interior in the axial direction, and a cylindrical attachment / detachment device 19 that fits onto the eccentric portion 16 is provided so that it can be attached. The outer diameter of the attachment tool 19 is formed to be slightly larger than the outer diameter of the plug 1. A rod-shaped portion 18 is formed in the axial direction of the attachment device 19, with a gap between them. Incidentally, as can be seen in Figure 9, the tip of the attachment device 19 has a shape resembling a crab's claw when viewed from the side, which is to reduce weight.

[0019] The movable piece 2 is roughly frustoconical in shape, with a larger area at the lower base than at the upper base, and its diameter widens from the upper base to the lower base. A protrusion 20 is provided on the side portion 21. The movable piece 2 of this embodiment shown in Figure 1 is composed of a plurality of divided bodies 2A, 2B, each having an opposing surface 23 with a receiving groove 22 having an inner wall shaped to match the fastening member 3. In other words, the division of the movable piece 2 is configured to divide the protrusion 20 in half along the length of the protrusion 20. In this embodiment, the multiple divided bodies 2A and 2B are a split structure divided into two, and the multiple protrusions 25 and recesses 26 are formed on opposing surfaces 23 that are in contact with each other, allowing the protrusions 25 and recesses 26 to engage with each other. In addition to the split structure described above, it is also possible to implement a four-part structure. The divided parts 2A and 2B have a receiving groove 22 formed to the extent that the fastening member 3 (nut 31) can contact it, and by bringing the opposing surfaces 23 of the divided parts 2A and 2B together, a fastening receiving space 24 is defined that prevents the fastening member 3 (nut 31) from spinning freely.

[0020] Note that the divided parts 2A and 2B are not necessarily completely separated as shown in the exploded view in Figure 3A, but may be joined together at their lower bottom surfaces in a hinge-like manner (Figure 3B), or, although not shown in the illustration, the tops of the protrusions 20 of the divided parts 2A and 2B may be joined together in a hinge-like manner. Furthermore, the movable piece 2 may be formed integrally with the nut 31 instead of being divided into parts 2A and 2B, or it can be implemented in a configuration in which the movable piece 2 is provided with an internal thread.

[0021] <Second Example> As shown in the second embodiment in Figure 4, the pipes, which are hollow cross-sectional members 4, can be connected in the axial direction. In other words, the bolts 30 that form the fastening member 3 connect the pipes 4 together in the axial direction by being inserted. The head of bolt 30 is housed inside the other movable piece 2.

[0022] <Third Example> As shown in the third embodiment in Figure 5, the pipes, which are hollow cross-sectional members 4, can be easily fastened together in a T-shape. In other words, the pipes 4 can be fastened together by inserting the bolt 30. The pipe 4 into which the bolt 30 is inserted radially has a hole 43 for inserting the bolt 30. A mounting section b is provided so that a pipe 4 into which a bolt 30 is inserted radially can be placed.

[0023] <Fourth Example> As shown in the fourth embodiment in Figure 6, a joint 5 (Figure 6A) having an axial projection 50 inside can be inserted into a pipe 4 (Figure 6B) having a groove 42 on its outer circumference 41 in the axial direction, together with a plug 1 and fastened with a bolt 30. After fastening with bolts 30 is complete, the decorative cap 51 is fitted into the rear opening of the joint 5 (Figures 6B, C). This eliminates the risk of the pipe 4 twisting when fastening it with bolt 30.

[0024] <Instructions for attaching to the pipe> The procedure for attaching the aforementioned connecting member to the pipe 4 will be explained using Figure 7. First, as shown in Figure 7A, the bolt 30 is inserted into the bolt insertion hole 16a of the plug 1. At this time, the bolt 30 will be pressed against the nut 31 inside the movable piece 2, but since the protrusion 20 of the movable piece 2 will come into contact with the end of the elongated hole 11, the movable piece 2 will not fall out of the plug 1. Furthermore, the nut 31 inside the movable piece 2 is prevented from rotating by contacting the fastening housing space 24 inside the movable piece, and the protrusion 20 of the movable piece 2 is prevented from rotating by contacting the slit 13 or elongated hole 11 of the plug 1, so that the bolt 30 does not spin freely even when screwed in. In other words, the protrusion 20 provided on the side portion 21 of the movable piece 2 is restricted by the elongated hole 11 in the direction of movement of the fastening member 3 (bolt 30, nut 31). Next, as shown in Figure 7B, when the bolt 30 is screwed into the nut 31, the head of the bolt 30 comes into contact with the bolt insertion hole 16a of the plug 1. Then, as shown in Figure 7C, when the bolt 30 is screwed further into the nut 31, the movable piece 2 moves toward the bolt insertion side. At the same time, the hollow cross-section member insertion portion 10 of the plug 1 expands in diameter due to the wedge effect. Furthermore, as shown in Figure 7D, when the bolt 30 is further screwed into the nut 31, the movable piece 2 moves toward the bolt insertion side, causing the hollow cross-section member insertion portion 10 of the plug 1 to expand further due to the wedge effect and press against the inner wall 40 of the pipe. By pressing against the inner wall 40 of the pipe, the plug 1 will not come out of the pipe 4. To remove plug 1 from pipe 4, simply reverse the procedure. When the bolt 30 is completely removed from the movable piece 2, the projection 20 of the movable piece 2 comes into contact with the end of the elongated hole 11 on the tip side of the plug 1, so the movable piece 2 can remain attached to the plug 1 without easily falling off. In short, because the slit 11a of the elongated hole 11 is narrower than the protrusion 20 of the movable piece 2, the movable piece 2 cannot easily pass through the slit 11a and will not fall out of the hollow cross-section member insertion part 10 of the plug 1. Although the hollow cross-sectional member insertion portion 10 of the plug 1 will expand in diameter even without a slit 11a narrower than the width of the protrusion 20 on the side portion 21 of the movable piece 2 at the end 12 of the elongated hole 10 of the plug 1 on the movable piece insertion side, providing the slit 11a makes it easier to expand in diameter.

[0025] <Installation procedure for fittings> The procedure for attaching the joint 5 of the connecting member will be explained using Figure 8. With the pipe 4 attached to the plug 1 to which the attachment tool 19 is attached, the fitting 5 is fitted (Figure 8A). The fastening tool 19 is molded to be slightly larger than the inner diameter of the joint 5. When the joint 5 is inserted into the plug 1 while compressing the fastening tool 19, the tip of the fastening tool 19 deforms inward. At this time, a spring action acts on the tip of the fastening tool 19, causing it to open outward, so that the fastening tool 19 presses tightly against the joint 5. As the joint 5 is rotated around the bolt insertion hole 16a into which the bolt 30 is inserted, the fastening device 19, which is in close contact with it, also rotates. As the joint 5 is rotated, the rod-shaped portion 18 of the attachment tool 19 comes into contact with the protruding portion 17 provided on the eccentric portion 16 of the plug 1 (Figure 8B). As the joint 5 is rotated further, the rod-shaped portion 18 of the attachment / detachment tool 19 bends, and as the joint 5 continues to rotate, the rod-shaped portion 18 of the attachment / detachment tool 19 returns to its original position with a "click" sound. (Figure 8C) Once the sound is emitted, it becomes impossible to remove the connector 5 from the plug 1 without rotating the connector 5 any further. The reason the rod-shaped portion 18 on the attachment device 19 is positioned vertically in Figure 8 is that if the rod-shaped portion 18 is bent multiple times, it will break and stop producing sound. Therefore, by inverting the attachment device 19, it is possible to restore the ability to produce sound. Furthermore, the mounting portion of the plug 1 attachment tool 19 has an eccentric portion 16 that is eccentric with respect to the bolt insertion hole 16a into which the bolt 30 is inserted. When the joint 5 is rotated, the attachment tool 19 moves in a direction that narrows the space between the inner surface of the joint 5 and the eccentric portion 16 of the plug 1. Due to the wedge effect, the attachment tool 19 exerts a force that presses the eccentric portion 16 against the inner surface of the joint 5, making it difficult to remove the joint 5 from the plug 1 (see Figure 9). To remove fitting 5 from plug 1, simply follow the reverse procedure. Although the diagram above shows the process in a counter-clockwise direction, the same results can be obtained in a clockwise direction.

[0026] Although embodiments have been described above based on the drawings, it should be noted that the present invention is not limited to the illustrated examples and includes design modifications and variations in application that are ordinarily performed by those skilled in the art, without departing from the technical concept. [Explanation of Symbols]

[0027] 1 plug 10 Hollow section member insertion part 11 long hole 11a Cut 12 End on the side where the movable piece is inserted 13 slits 14. Opposite side (bolt insertion side) 16 Eccentric part 16a Bolt insertion hole 17 Protrusion 18 Rod-shaped part 19 Attachment / detachment tool 2 Moving pieces 20 protrusions 21 Side 22 Storage grooves 23 Opposing surfaces 24 Fastening storage space 25 Convex part 26 recesses 2A, 2B split body 3 Fastening members 30 volts 31 nuts 4. Hollow cross-sectional member (pipe) 40 Inner wall 41 Outer perimeter 42 Groove 43 holes b Mounting section 5. Joints 50 protrusions 51 Cosmetic cap

Claims

1. A connecting member consisting of a plug, a movable piece, and a fastening member that are inserted into and connected to a hollow cross-section member, The plug has an elongated hole in the hollow cross-sectional member insertion portion that is inserted into the hollow cross-sectional member. The movable piece is housed within the insertion portion of the hollow cross-section member, and the side of the movable piece is provided with a projection that restricts the movement direction of the fastening member by the elongated hole. The plug and the movable piece are fastened together by the fastening member, and as the movable piece moves, the diameter of the insertion portion for the hollow cross-section member expands, allowing it to press against the inner wall of the hollow cross-section member. A connecting member characterized in that the movable piece remains in place without falling out of the hollow cross-section member insertion portion even when the fastening member is fastened or unfastened.

2. The movable piece is capable of accommodating a portion of the fastening member and consists of a plurality of divided bodies, each having an opposing surface with a accommodating groove that contacts the fastening member. In a connected state in which the plurality of divided bodies are joined so that their opposing surfaces abut each other, the receiving grooves of the plurality of divided bodies define a fastening receiving space that abuts a portion of the fastening member. The connecting member according to claim 1, characterized in that it has a configuration that allows a portion of the fastening member to be accommodated in the fastening accommodation space.

3. The connecting member according to claim 1, characterized in that the insertion portion of the hollow cross-sectional member of the plug has a slit formed in the axial direction together with the elongated hole, with the end on the movable piece insertion side being open, or the slit is formed in place of the elongated hole.

4. The connecting member according to claim 1, characterized in that a slit narrower than the width of the protrusion is formed in the axial direction at the end of the elongated hole on the side where the movable piece is inserted, which is provided in the insertion portion of the hollow cross-sectional member of the plug.

5. A groove is provided in the axial direction on the outer circumference of the hollow cross-sectional member. A projection is provided inside the joint into which the hollow cross-sectional member is inserted. The hollow cross-sectional member can be inserted into the joint by the engagement of the groove and the projection. The connecting member according to claim 1, characterized in that the fastening member is inserted into the joint together with the plug, and the portion of the plug that inserts into the hollow cross-sectional member is inserted into the hollow cross-sectional member, thereby enabling fastening of the plug and the hollow cross-sectional member.

6. On the side of the plug opposite to the side where the movable piece is inserted, an eccentric portion is provided that is eccentric to the bolt insertion hole into which the fastening member, the bolt, is inserted, and a projection is formed on the eccentric portion that protrudes in the axial direction, A detachable attachment device is attached to the eccentric portion, which has a rod-shaped portion that protrudes in the axial direction. The connecting member according to claim 1, characterized in that when the joint into which the hollow cross-sectional member is inserted is fitted and rotated around the bolt insertion hole into which the bolt is inserted, the rod-shaped part of the attachment tool makes a sound when it passes over the protruding part of the plug, and the attachment tool exerts a force that presses against the eccentric part and the inside of the joint, thereby enabling the joint to be fixed.

7. The hollow cross-sectional member is a pipe, and the pipe is insertable into the insertion portion of the hollow cross-sectional member of the plug into which the movable piece is inserted. The fastening member consists of a bolt and a nut. The bolt and the nut housed in the movable piece, which has an enlarged diameter and a roughly frustoconical shape, are fastened together, and the movable piece is screwed forward, thereby expanding the diameter of the hollow cross-sectional member insertion portion, and enabling the hollow cross-sectional member insertion portion to press against the inner wall of the pipe. The connecting member according to claim 1 or 5, characterized in that even when the bolt and nut are fastened or unfastened, the protrusion provided on the movable piece abuts against the end of the elongated hole provided in the hollow cross-section member insertion part, thereby preventing the movable piece from falling out of the hollow cross-section member insertion part.

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