Scaffolding connection structure and connection device

Abstract

To provide a scaffold connection structure and a connection device which can easily perform connection work of a scaffold and a building.SOLUTION: There is provided a scaffold connection structure for connecting a scaffold 2 and a building 5 by a connection device 1, wherein the connection device 1 has: a first clamp 10 mounted on the scaffold 2; a first cylindrical member 20 which cylindrically extends to the building 5 from the first clamp 10 and is mounted on the first clamp 10 so as to be relatively rotatable around a shaft core of a cylinder, and has a male screw 21 provided on the outer peripheral surface; a second cylindrical member 30 which has a female screw 31 screwed with the male screw 21 of the first cylindrical member 20, extends to the building 5 and has a cylindrical shape; and a second clamp 40 which is mounted in the vicinity of an end opposite to an end side to which the first cylindrical member 20 is inserted in the second cylindrical member 30, and is mounted on the building 5.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a scaffolding connection structure and a connection device that connects a scaffolding to a building using the connection device. [Background technology]

[0002] In order to prevent temporary scaffolding set up around a building from collapsing, a connecting structure has traditionally been used to connect the scaffolding to the building. One end of a single pipe long enough to reach the scaffolding to the building's frame (e.g., H-beam) is attached to the scaffolding's support with a perpendicular clamp, while the other end of the single pipe is attached to the frame with two catch clamps.

[0003] However, with conventional connecting structures, it was difficult to adjust the attachment positions of the orthogonal clamps to the single pipes in order to maintain a consistent distance between the scaffolding posts and the main body at multiple locations, which required multiple workers and was time-consuming and labor-intensive. Summary of the Invention [Problem to be solved by the invention]

[0004] In view of the above circumstances, an object of the present invention is to provide a scaffolding connection structure and a connection device that make it possible to easily connect scaffolding to a building. [Means for solving the problem]

[0005] In order to solve the above problems, the scaffolding connection structure according to the present invention comprises: "A scaffolding connection structure in which the scaffolding and the building are connected by a connecting device, The coupling device is a first clamp attached to the scaffold; a first cylindrical member that extends cylindrically from the first clamp toward the building, is attached to the first clamp so as to be rotatable relative to the first clamp about its axis, and has a male thread on its outer peripheral surface; A cylindrical second cylindrical member having a female thread that is threadedly engaged with the male thread of the first cylindrical member and extending to the building; a second clamp attached to the building and near an end of the second tubular member opposite to the end closer to the first clamp; Equipped with The second cylindrical member includes a nut portion having the female screw, and a first cylindrical member extending from the nut portion along the axis. tube The nut portion and the pipe portion are joined by welding.

[0006] According to this configuration, when the first tubular member of the connecting device is rotated around its axis, because the first clamp is attached to the scaffolding and the second tubular member is attached to the building, the first clamp and the second tubular member do not rotate together with the first tubular member, but the first tubular member rotates relative to the second tubular member. As a result, the overall length of the connecting device can be extended or shortened depending on the direction of rotation of the first tubular member due to the action of the threads of the male thread of the first tubular member and the female thread of the second tubular member, which are screwed together. This makes it easy to adjust the distance between the scaffolding and the building, and also makes it easy for even a small number of people (one person) to connect the scaffolding and the building.

[0007] Further, the coupling device according to the present invention comprises: "A connecting device for connecting a scaffolding to a building, The coupling device comprises: A first clamp; a first cylindrical member extending cylindrically from the first clamp, attached to the first clamp so as to be rotatable relative to the first clamp about an axis of the cylinder, and having a male thread on an outer peripheral surface; a cylindrical second cylindrical member having a female thread that is threadedly engaged with the male thread of the first cylindrical member; Equipped with The second cylindrical member includes a nut portion having the female screw, and a cylindrical member extending from the nut portion along the axis. tubeThe nut portion and the pipe portion are joined by welding.

[0008] According to this configuration, by attaching the first clamp of the connecting device to the scaffolding and attaching the end of the second tubular member opposite the end into which the first tubular member is inserted to the building, the above-mentioned connecting structure of the scaffolding can be constructed, and the same effects as those described above can be achieved. Note that a catch clamp commonly used on construction sites can be used as the clamp for attaching the end of the second tubular member opposite the end into which the first tubular member is inserted to the building.

[0009] In addition to the above configuration, the coupling device according to the present invention further comprises: "A second clamp is detachably attached to the second cylindrical member near the end opposite to the side close to the first clamp, The invention is characterized in that it further comprises:

[0010] According to this configuration, since the second clamp for attaching the second tubular member to the building is provided, there is no need to procure a clamp equivalent to the second clamp on site, and the above-mentioned scaffolding connection structure can be easily constructed. In addition, since the second clamp is detachable from the second tubular member, the attachment position of the second clamp in the axial direction of the second tubular member can be changed depending on the distance between the scaffolding and the building, and it can easily be adapted to various distances between the scaffolding and the building. [Effects of the Invention]

[0011] As described above, the effect of the present invention is to provide a scaffolding connection structure and connection device that make it possible to easily perform the work of connecting scaffolding to a building. [Brief explanation of the drawings]

[0012] [Figure 1](a) is an explanatory diagram showing a side view of the connecting structure of scaffolding using the connecting device of the first embodiment, (b) is an explanatory diagram showing a plan view of the vicinity of the first clamp in (a), and (c) is an explanatory diagram showing a plan view of the vicinity of the boundary between the first tubular member and the second tubular member in (a). [Figure 2] (a) is an explanatory diagram showing a side view of the connecting structure of scaffolding using a connecting device that is a second embodiment of the present invention, (b) is an explanatory diagram showing a plan view of the vicinity of the first clamp in (a), and (c) is an explanatory diagram showing a plan view of the vicinity of the boundary between the first tubular member and the second tubular member in (a). [Figure 3] (a) is an explanatory diagram showing a plan view of the vicinity of the first clamp in a scaffolding connection structure using a connecting device that is a third embodiment of the present invention, and (b) is an explanatory diagram showing a side view of the vicinity of the base end of the second tubular member in (a). DETAILED DESCRIPTION OF THE INVENTION

[0013] below , th A connecting device 1 according to one embodiment and a scaffolding connecting structure using the same will be described in detail with reference to FIG. The first embodiment is a reference example, but among the descriptions of the first embodiment, descriptions relating to common points with the second and third embodiments described below, which are embodiments of the present invention, are descriptions relating to embodiments of the present invention. 1(c) shows the second tubular member 30 in cross section. The connecting device 1 of this embodiment is for connecting a temporary scaffolding 2 and a building 5. The connecting device 1 includes a first clamp 10, a first tubular member 20 extending cylindrically from the first clamp 10, a cylindrical second tubular member 30 into which a portion of the first tubular member 20 is inserted, and a second clamp 40 attached to the second tubular member 30. In the following description, the side of the first tubular member 20 and the second tubular member 30 closer to the first clamp 10 will be referred to as the base end side, and the side farther from the first clamp 10 will be referred to as the tip end side.

[0014] First clamp 10 can be attached to a pipe support 3 of scaffolding 2. As shown in FIG. 1(b), first clamp 10 includes a fixed part 11 having an L-shaped fixed-side recess 11a recessed in a semicircular arc on the inner corner, and a movable part 12 rotatably attached to one end of fixed part 11 and having a movable-side recess 12a recessed in a semicircular arc on the side facing fixed-side recess 11a. First clamp 10 also includes a tightening bolt 13 rotatably attached to the other end of fixed part 11, and a tightening nut 14 threaded onto tightening bolt 13. The rotation axis of movable part 12 and the rotation axis of tightening bolt 13 are arranged parallel to the central axes of the arcs of fixed-side recess 11a and movable-side recess 12a.

[0015] Movable part 12 is rotatably attached to fixed part 11 at a location corresponding to the tip of the L-shaped portion extending to the left and right. Movable part 12 has receiving part 12b extending radially outward from the end opposite the rotation axis of movable-side recess 12a, and slit 12c (see FIG. 1(a)) cut into receiving part 12b in a direction perpendicular to the rotation axis to allow tightening bolt 13 to pass through.

[0016] This first clamp 10 allows the support pole 3 to be positioned in the fixed-side recess 11a from outside the side surface (circumferential surface) of the support pole 3 by opening the movable part 12 and the tightening bolt 13 relative to the fixed part 11. To attach the first clamp 10 to the support pole 3, with the support pole 3 positioned in the fixed-side recess 11a, the movable part 12 is closed and then the tightening bolt 13 is closed and inserted into the slit 12c of the movable part 12. When the tightening nut 14 is then tightened, the tightening nut 14 presses the movable part 12 toward the fixed part 11 via the receiving part 12b, and the first clamp 10 is attached to the support pole 3 so that the fixed part 11 and the movable part 12 sandwich the support pole 3 therebetween.

[0017] The first cylindrical member 20 has a male thread 21 provided on the outer surface over almost the entire axial length, a lid portion 22 closing the base end side closer to the first clamp 10, a connection hole 23 passing through the axial direction at the center of the lid portion 22, a connection pin 25 rotatably inserted into the connection hole 23, and a washer 26 provided between the first clamp 10 and the lid portion 22 and through which the connection pin 25 is inserted.

[0018] Male thread 21 is provided from the base end of first cylindrical member 20 to near the tip. Cover portion 22 is attached by welding. Connection pin 25 is provided to pass through connection hole 23 and a connection hole (not shown) provided in fixed portion 11 of first clamp 10, and has large-diameter portions 25a at both ends whose diameters are larger than the inner diameters of connection hole 23 and the like. Connection pin 25 attaches first cylindrical member 20 to first clamp 10 so as to be rotatable about its axis relative to first clamp 10, and large-diameter portions 25a at both ends prevent axial movement relative to first clamp 10.

[0019] The second cylindrical member 30 extends cylindrically, and has an internal thread 31 that is threadedly engaged with the external thread 21 on its inner circumferential surface near the base end where the first cylindrical member 20 is inserted. The internal diameter of the second cylindrical member 30 on the tip side beyond the portion where the internal thread 31 is provided is larger than the external diameter of the first cylindrical member 20.

[0020] Although detailed illustrations are omitted, the second clamp 40 comprises a fixed portion 41 that is L-shaped and has a fixed-side recess that is recessed in a semicircular arc on the inner corner side, a movable portion 42 that is rotatably attached to one end side of the fixed portion 41 and has a movable-side recess that is recessed in a semicircular arc on the side facing the fixed-side recess, a tightening bolt 43 that is rotatably attached to the other end side of the fixed portion 41, and a tightening nut 44 that is threaded onto the tightening bolt 43.

[0021] The rotation axis of movable part 42 of second clamp 40 and the rotation axis of clamping bolt 43 are arranged parallel to the central axes of the arcs of the fixed-side recess and the movable-side recess. Movable part 42 has a receiving part extending radially outward from the end opposite the rotation axis of the movable-side recess, and a slit cut into the receiving part in a direction perpendicular to the rotation axis and large enough to allow clamping bolt 43 to pass through. Second clamp 40 has the same configuration as first clamp 10, including fixed part 41, movable part 42, clamping bolt 43, and clamping nut 44.

[0022] The second clamp 40 also includes a U-shaped catch portion 45 attached to the side of the fixing portion 41 opposite to the fixed-side recess, and a catch bolt 46 screwed into the catch portion 45.

[0023] The catch portion 45 is attached to the fixed portion 41 so that the open portion of the U-shape faces the axial direction of the rotation shaft of the movable portion 42 and is unable to rotate relative to the fixed portion 41. Note that the catch portion 45 may also be attached to be rotatable relative to the fixed portion 41. The catch bolt 46 is a hexagonal bolt with a hexagonal head on the outer periphery. The catch bolt 46 penetrates one of the two parallel rod-shaped portions of the U-shaped catch portion 45 that is farther from the fixed portion 41 and is screwed in so that its tip faces the opposite portion.

[0024] Similar to the first clamp 10, this second clamp 40 can be attached to the second cylindrical member 30 by positioning the second cylindrical member 30 between the fixed portion 41 and the movable portion 42, inserting the tightening bolt 43 into the slit in the movable portion 42, and tightening the tightening nut 44, so that the second cylindrical member 30 is sandwiched between the fixed portion 41 and the movable portion 42. Therefore, the second clamp 40 is detachably attached to the second cylindrical member 30.

[0025] In addition, the second clamp 40 can be attached to the building 5 by tightening the catch bolt 46 while positioning the flange portion 6b of the H-beam 6 described later on the building 5 inside the U-shaped part of the catch portion 45.

[0026] Two second clamps 40 are detachably attached to the second cylindrical member 30 near the tip end side opposite the base end side where the first cylindrical member 20 is inserted, spaced apart in the axial direction of the second cylindrical member 30. The two second clamps 40 are attached to the second cylindrical member 30 with the catch portions 45 facing up, so that the open sides of the U-shaped catch portions 45 face each other.

[0027] In the connecting device 1 of this embodiment, when the first cylindrical member 20 is rotated relative to the second cylindrical member 30 around its axis, the overall length of the connecting device 1 can be extended or shortened depending on the direction of rotation of the first cylindrical member 20.

[0028] In this embodiment, a plurality of protrusions protruding outward may be provided near the base end of the first cylindrical member 20, and the provision of the protrusions makes it easier to rotate the first cylindrical member 20. Also, a lock nut may be provided that is threaded onto the male thread 21 of the first cylindrical member 20, and by adjusting the length of the coupling device 1 and then tightening the lock nut toward the second cylindrical member 30, rotation of the first cylindrical member 20 can be prevented.

[0029] Next, the connection between the scaffolding 2 and the building 5 using the connecting device 1 of this embodiment will be described. Here, the scaffolding 2 is provided along the building 5 and has a plurality of supports 3 extending up and down. Meanwhile, the building 5 has a plurality of H-beams 6 that form the building's frame. The H-beams 6 have web portions 6a extending up and down and flange portions 6b extending left and right from both the top and bottom ends of the web portions 6a.

[0030] First, the first clamp 10 is positioned near the support 3 of the scaffolding 2, and the tip side of the second tubular member 30 is positioned below the H-beam 6 of the building 5, and the two second clamps 40 are attached to the lower flange portion 6b of the H-beam 6. At this time, it is desirable to loosen the tightening nut 44 of the second clamp 40 so that it can slide relative to the second tubular member 30. Then, by sliding the second tubular member 30 relative to the second clamp 40 and rotating the first tubular member 20 about its axis, the length of the connecting device 1 is adjusted while the first clamp 10 is attached to the support 3. This completes the construction of a scaffolding connection structure using the connecting device 1.

[0031] After the scaffolding 2 and the building 5 are connected by the connecting device 1, the first tubular member 20 is rotated about its axis to adjust (fine-tune) the distance between the scaffolding 2 and the building 5 so that it is constant. In detail, when the first tubular member 20 of the connecting device 1 is rotated about its axis, the first clamp 10 is attached to the support 3 of the scaffolding 2, and the second tubular member 30 is attached to the H-beam 6 of the building 5 by the two second clamps 40, so the first clamp 10 and the second tubular member 30 do not rotate together with the first tubular member 20, but the first tubular member 20 rotates relative to the second tubular member 30.

[0032] When the first cylindrical member 20 rotates relative to the second cylindrical member 30, the thread action of the male thread 21 of the first cylindrical member 20 and the female thread 31 of the second cylindrical member 30, which are threaded together, allows the overall length of the connecting device 1 to expand or contract depending on the direction of rotation of the first cylindrical member 20. By expanding and contracting the connecting device 1, the distance between the scaffolding 2 and the building 5 can be adjusted.

[0033] The scaffolding 2 and the building 5 are connected at multiple locations by connecting devices 1, and the distance between the scaffolding 2 and the building 5 is adjusted at each connecting device 1 so that it is constant.

[0034] Thus, according to this embodiment, when the first clamp 10 is attached to the support 3 of the scaffolding 2 and the second clamp 40 is attached to the H-beam 6 of the building 5, and the first tubular member 20 is rotated around its axis, the overall length of the connecting device 1 can be extended or shortened depending on the direction of rotation of the first tubular member 20, so that the distance between the scaffolding 2 and the building 5 can be easily adjusted and the connecting work between the scaffolding 2 and the building 5 can be easily performed by a small number of people (one person).

[0035] Furthermore, since the scaffolding is provided with the second clamp 40 for attaching the second tubular member 30 to the building 5, there is no need to procure a clamp equivalent to the second clamp 40 on-site, and the above-mentioned scaffolding connection structure can be easily constructed. Furthermore, since the second clamp 40 is detachably attached to the second tubular member 30, the attachment position of the second clamp 40 in the axial direction of the second tubular member 30 can be changed depending on the distance between the scaffolding 2 and the building 5 (H-steel 6), and various distances between the scaffolding 2 and the building 5 can be easily accommodated.

[0036] Furthermore, since the two second clamps 40 are used to attach the H-shaped steel 6 of the building 5, when connecting the scaffolding 2, if the second clamp 40 is attached to the H-shaped steel 6 before the first clamp 10 is attached to the support 3 of the scaffolding 2, the two second clamps 40 can prevent the second tubular member 30 (connecting device 1) from tilting, making the connecting work easier.

[0037] Furthermore, because the H-beam steel 6 is attached by two second clamps 40, even if one of the second clamps 40 becomes detached from the H-beam steel 6 for some reason, the remaining second clamp 40 can prevent the steel from falling off the H-beam steel 6, thereby improving safety. Furthermore, because both second clamps 40 are detachable from the second tubular member 30, the distance between the two second clamps 40 can be adjusted to suit various widths of the flange portion 6b of the H-beam steel 6.

[0038] Next, a coupling device 1A according to a second embodiment of the present invention will be described with reference to Fig. 2. The coupling device 1A of the second embodiment differs from the coupling device 1 of the first embodiment only in the configuration of the second cylindrical member 30A, and the other configurations are the same. In the following, the same components as those of the first embodiment are denoted by the same reference numerals, and their description will be omitted.

[0039] The second cylindrical member 30A of this connecting device 1A includes a nut portion 32 having a female thread 31 that is threadedly engaged with the male thread 21 of the first cylindrical member 20, and a pipe portion 33 that extends cylindrically from the nut portion 32 along the axis of the female thread 31 and into which the first cylindrical member 20 is inserted. No female thread is formed on the inner peripheral surface of the pipe portion 33. In this embodiment, the nut portion 32 and the pipe portion 33 are joined by welding.

[0040] The coupling device 1A of the second embodiment can achieve the same effects as the above-described coupling device 1. In addition, in the coupling device 1A, the second cylindrical member 30A is configured with the nut portion 32 having the female thread 31 and the pipe portion 33. Therefore, compared to the second cylindrical member 30 in which the female thread 31 is formed on the inner peripheral surface of the pipe, the female thread 31 can be formed more easily, and the cost of the coupling device 1A can be reduced.

[0041] Next, a coupling device 1B according to a third embodiment of the present invention will be described with reference to FIG. 3. The coupling device 1B of the third embodiment differs from the coupling device 1A of the second embodiment only in the configuration of the base end side of the first cylindrical member 20A, and the other configurations are the same. In the following, the same components as those described above will be assigned the same reference numerals and will not be described again. Note that FIG. 3 shows a cross section of the second cylindrical member 30A.

[0042] The first cylindrical member 20A of this connecting device 1B has, in addition to a male screw 21 provided on the outer peripheral surface of the cylinder, an attachment stay 27 attached to the base end side, a rotating attachment member 28 for attaching the first clamp 10 to the attachment stay 27 so that it can rotate relatively around the axis of the cylinder, and a handle 29 extending outward near the base end of the cylinder.

[0043] The mounting stay 27 has a flat base plate portion 27a with a rectangular outer shape and a pair of flat leg plate portions 27b extending from two parallel sides of the base plate portion 27a. The pair of leg plate portions 27b extend parallel to each other in the same direction from the base plate portion 27a. Therefore, the mounting stay 27 is formed in a U-shape. The base plate portion 27a of the mounting stay 27 is positioned axially outward of the male thread 21, and the pair of leg plate portions 27b are welded to the male thread 21 with the pair of leg plate portions 27b in contact with the male thread 21.

[0044] The rotatable mounting member 28 is composed of a bolt 28a and a locking nut 28b threaded onto the bolt 28a. The bolt 28a passes through the fixed portion 11 of the first clamp 10 from the fixed-side recess 11a side, through the fixed portion 11 and the base plate portion 27a of the mounting stay 27, and its male thread portion protrudes into the space between the pair of leg plate portions 27b. The locking nut 28b is in contact with the fixed portion 11 of the first clamp 10 and the base plate portion 27a of the mounting stay 27, and is threaded onto the bolt 28a with such tightening strength that the first clamp 10 can rotate around the axis of the first tubular member 20A. Although not shown in detail, the locking nut 28b has a member provided inside that applies rotational resistance, preventing loosening.

[0045] The handle 29 is a pipe with an outer diameter smaller than the diameter of the male screw 21 of the first cylindrical member 20A. The handle 29 is attached by welding with both ends extending outward, passing through the male screw 21 perpendicular to the axis of the first cylindrical member 20A.

[0046] In the connecting device 1B of the third embodiment, the outer diameter of the nut portion 32 of the second cylindrical member 30A is set to be the same as the outer diameter of the pipe portion 33.

[0047] The coupling device 1B of the third embodiment can achieve the same effects as the coupling device 1 and coupling device 1A described above. Additionally, in the coupling device 1B, the rotatable mounting member 28 that mounts the first clamp 10 and the first tubular member 20A is composed of a bolt 28a and a locking nut 28b, which facilitates assembly of the first clamp 10 and the first tubular member 20A and reduces costs. Furthermore, the first tubular member 20A is provided with a handle 29, which allows the first tubular member 20A to be easily rotated by operating the handle 29, facilitating the coupling operation.

[0048] As a modification of the third embodiment, the U-shaped mounting stay 27 may be configured to rotate around an axis perpendicular to the axis of the first cylindrical member 20A. Specifically, a pair of leg plate portions 27b of the U-shaped mounting stay 27 may be fastened to the first cylindrical member 20A with bolts. When the bolts are loosened, the mounting stay 27 can be rotated around an axis perpendicular to the axis of the first cylindrical member 20A, and when the bolts are tightened, the mounting stay 27 is fixed so as not to rotate. This allows the first clamp 10 to be attached to the pillar 3 without any problems by rotating and adjusting the mounting stay 27, even if the central axis of the pillar 3 is not accurately positioned on the extension line of the axes of the first cylindrical member 20A and the second cylindrical member 30A.

[0049] Alternatively, instead of the handle 29, two opposing through-holes may be formed in the first cylindrical member 20A at positions corresponding to the positions where the handle 29 passes through. This allows the tip of a rod-shaped member to be inserted into the through-holes and used as a handle to rotate the first cylindrical member 20A.

[0050] The present invention has been described above by citing preferred embodiments, but the present invention is not limited to the above embodiments, and various improvements and design changes are possible within the scope of the gist of the present invention.

[0051] For example, in the above embodiment, the first clamp 10 is shown attached to the support 3 of the scaffolding 2, but this is not limited to this, and the first clamp 10 may also be attached to a pipe that constitutes the scaffolding 2 other than the support 3.

[0052] Furthermore, in the above embodiment, the second clamp 40 is shown attached to the H-beam 6 of the building 5, but this is not limited to this, and the second clamp 40 may also be attached to a C-beam or L-beam that constitutes the frame of the building 5. [Explanation of symbols]

[0053] 1 Coupling device 1A coupling device 2. Scaffolding 5 Buildings 10 First clamp 20 First cylindrical member 21 Male thread 25 connecting pins 26 Washer 30 Second cylindrical member 30A Second cylindrical member 31 Female thread 40 Second clamp

Claims

1. A scaffolding connection structure in which the scaffolding and the building are connected by a connecting device, The coupling device is a first clamp attached to the scaffold; a first cylindrical member that extends cylindrically from the first clamp toward the building, is attached to the first clamp so as to be rotatable relative to the first clamp about its axis, and has a male thread on its outer peripheral surface; A cylindrical second cylindrical member having a female thread that is threadedly engaged with the male thread of the first cylindrical member and extending to the building; a second clamp attached to the building and near an end of the second tubular member opposite to the end closer to the first clamp; Equipped with The second cylindrical member includes a nut portion having the female thread and a pipe portion extending cylindrically from the nut portion along the axis and into which the first cylindrical member is inserted, and the nut portion and the pipe portion are joined by welding. A scaffolding connection structure characterized by:

2. A connecting device for connecting a scaffolding to a building, The coupling device comprises: A first clamp; a first cylindrical member extending cylindrically from the first clamp, attached to the first clamp so as to be rotatable relative to the first clamp about an axis of the cylinder, and having a male thread on an outer peripheral surface; a cylindrical second cylindrical member having a female thread that is threadedly engaged with the male thread of the first cylindrical member; Equipped with The second cylindrical member includes a nut portion having the female thread and a pipe portion extending cylindrically from the nut portion along the axis and into which the first cylindrical member is inserted, and the nut portion and the pipe portion are joined by welding. A coupling device characterized by:

3. a second clamp that is detachably attached to the second cylindrical member near an end thereof opposite to the end close to the first clamp; 3. The coupling device of claim 2, further comprising:

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