Welding equipment

Abstract

The present invention provides a welding apparatus that allows welding to be performed while moving welding torches facing multiple sides, thereby enabling efficient welding operations. [Solution] The welding device comprises a base portion 11 attached to the first side A1 of the object to be welded A by a magnet 24, a torch moving portion 15 and a welding torch 14 supported by the base portion, the torch moving portion comprises a pivot portion 16 rotatably supported by the base portion, and an articulated robot 13 rotatably supported by the pivot portion and having a welding torch connected to its tip, the pivot portion rotates so that the articulated robot can be positioned to protrude outward from the side edges on both sides in the width direction of the first side, and the arm portion 42 of the articulated robot rotates so that the welding torch can be moved to face the second side A2 and the third side A3 while welding.

Description

Technical Field

[0001] The present invention relates to a welding apparatus.

Background Art

[0002] Conventionally, column welding work at construction sites has been performed manually by skilled welders. However, the number of new entrants to the entire construction industry has decreased, and especially for welding work, skill acquisition is often difficult, leading to a marked labor shortage. As a countermeasure, development of welding apparatuses that enable on-site welding even by workers who are not skilled welders has been promoted. On the other hand, the environment for performing column welding at construction sites is by no means suitable for robotic work. Even if steel columns to be welded are on the same floor, there are a plurality of sizes, and the sizes also change when the construction floor changes. As a solution to this, a welding robot using a guide rail is known (see, for example, Patent Document 1).

[0003] The welding robot of Patent Document 1 requires preparation of a large number of guide rails and reassembly into a rail configuration matched to each column size every time. Further, conventional welding robots attach guide rails around a column and operate the robot to rotate around the column, resulting in poor construction efficiency for welding work. For this reason, the present inventors have proposed a welding apparatus that is attached to a welding target with a magnet (see, for example, Patent Document 2). The welding apparatus of Patent Document 2 can be easily attached to a predetermined position without taking time and effort for attachment, so that welding work can be performed efficiently.

Prior Art Literature

Patent Literature

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problem to be Solved by the Invention

[0005] However, while welding apparatuses like the one described in Patent Document 2 can be easily mounted in a predetermined position, the range in which the welding torch can be moved by the articulated robot is limited. Moreover, because it is attached to the side of the workpiece using magnets, it is not easy to attach a large articulated robot. Therefore, in order to perform welding while appropriately facing and moving the welding torch to multiple sides, the welding apparatus had to be repeatedly reattached and welded, leaving room for improvement.

[0006] This invention has been made in view of the above-mentioned problems, and aims to provide a welding apparatus that can perform welding while moving welding torches facing multiple sides, thereby enabling efficient welding work. [Means for solving the problem]

[0007] To achieve the above objective, the welding apparatus according to the present invention comprises a base portion attached to a first side surface of a workpiece by magnet, a torch moving portion supported by the base portion, and a welding torch connected to the torch moving portion, wherein the torch moving portion comprises a pivot portion rotatably supported by the base portion about a first vertical axis, and an articulated robot rotatably supported about a second vertical axis at a position spaced apart from the first vertical axis of the pivot portion, with the welding torch connected to its tip, wherein the pivot portion can rotate about the first vertical axis to position the articulated robot so as to protrude outward from the side edge on both sides in the width direction of the first side surface, and the articulated robot comprises an arm portion, wherein the arm portion rotates about the second vertical axis to move the welding torch so as to face the second side surface and the third side surface provided on both sides in the width direction of the first side surface, and welding is possible.

[0008] According to the welding apparatus of the present invention, the pivot portion rotates around the first vertical axis, allowing the articulated robot to be positioned so that it protrudes outward from the side edge on both sides in the width direction of the first side surface. This allows the articulated robot to be positioned in a location where it can perform welding work on the second and third side surfaces provided on both sides in the width direction of the first side surface.

[0009] In this position, the arm of the articulated robot rotates around the second vertical axis, allowing the welding torch to face both the second and third sides. Therefore, welding can be performed not only on the first side, but also on the second and third sides using the welding torch.

[0010] Since the base supporting the torch's moving part is attached to the first side of the workpiece by magnets, the welding device is easy to install. Moreover, since welding can be performed on the second and third sides with the welding device attached to the first side, there is no need to reattach the welding device to each side.

[0011] Furthermore, because the articulated robot is moved by a pivot section, the torch movement section can be simplified, reducing the weight of the welding equipment. Therefore, even if the welding equipment performs welding not only on the first side but also on the second and third sides, it can be attached to the first side with a magnet and welding can be performed on each side, eliminating the need for complicated installation of the welding equipment.

[0012] The welding apparatus according to the present invention may be configured such that the pivot portion rotates around the first vertical axis, allowing the second vertical axis to be positioned outside the side edge on both sides in the width direction of the first side surface.

[0013] According to this invention, the articulated robot can rotate around a position outside the side edge on both sides in the width direction of the first side surface, making it easier to operate the connected welding torch facing the second and third side surfaces.

[0014] The welding apparatus according to the present invention may be capable of welding while the welding torch is moved so as to face the first side surface in a desired orientation, and also capable of welding while moving so as to face the second side surface and the third side surface in the desired orientation.

[0015] According to this invention, welding can be performed on each side using the same welding conditions, such as the torch angle and torch inclination angle, making it easier to achieve consistent welding quality on each surface.

[0016] The welding apparatus according to the present invention has an arm portion of the articulated robot that is supported by the pivot portion via a rotating portion that can rotate about the second vertical axis, and has a base arm portion that rotates vertically with respect to the rotating portion, and a tip arm portion that is connected to the welding torch and rotates vertically with respect to the base arm portion, and the welding torch may be connected to the tip arm portion so as to be rotatable about the axis of rotation within a range of half a turn or more.

[0017] According to this invention, even if the second side and the third side are arranged facing opposite directions, when the articulated robot moves the welding torch to the opposing position on the second side and the opposing position on the third side, it is easy to position the welding torch in the same direction relative to each side.

[0018] In the welding apparatus according to the present invention, the tip of the welding torch may be positioned at an offset location with respect to the rotation axis.

[0019] According to this invention, when a welding torch is moved by a multi-joint robot, even if the angle of the rotation axis extending from the tip arm with respect to each side is small, it is possible to easily position the tip of the welding torch facing each side in a desired direction. [Effects of the Invention]

[0020] According to the present invention, it is possible to provide a welding apparatus that can perform welding while moving welding torches facing multiple sides, thereby enabling efficient welding work. [BRIEF DESCRIPTION OF THE DRAWINGS]

[0021] [Figure 1] FIG. 1 is a perspective view of a welding apparatus according to the present embodiment. [Figure 2] FIG. 2 is a perspective view showing a state where the welding apparatus according to the present embodiment is attached to a workpiece to be welded. [Figure 3] FIG. 3 is an exploded perspective view showing a base portion and a pivot portion of the welding apparatus according to the present embodiment. [Figure 4] FIG. 4 is a perspective view of the base portion of the welding apparatus according to the present embodiment as viewed from the workpiece to be welded side. [Figure 5] (a) to (c) are schematic plan views illustrating an operation of welding a plurality of side surfaces by the welding apparatus according to the present embodiment. [DESCRIPTION OF EMBODIMENTS]

[0022] Hereinafter, a welding apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5.

[0023] As shown in FIGS. 1 to 4, the welding apparatus 10 includes a base portion 11 attached to a workpiece to be welded (a steel column in the present embodiment) A, a torch moving portion 15 supported by the base portion 11, and a welding torch 14 connected to the torch moving portion 15.

[0024] The base portion 11 includes a substantially plate-shaped connecting portion 21, a base main body portion 22 disposed on one surface 21a of the connecting portion 21, and a bracket 12 disposed on a connecting surface 21b which is the other surface of the connecting portion 21. The base main body portion 22 is formed in a substantially rectangular parallelepiped shape. The connecting surface 21b is formed to have a substantially rectangular outer shape. The base main body portion 22 is disposed on the surface 21a opposite to the connecting surface 21b. A surface 22a of the base main body portion 22 parallel to the connecting surface 21a is smaller than the connecting surface 21a. Handles 23 are respectively attached to both side surfaces 22b of the base main body portion 22. A facing surface 22c facing outward of the base main body portion 22 and facing the workpiece to be welded A is formed to have a substantially rectangular outer shape.

[0025] The base portion 11 is attached to the first side A1 of the object to be welded A by magnets 24. Magnets 24 are attached to the opposing surface 22c of the base body portion 22. In this embodiment, six magnets 24 are arranged on the opposing surface 22c. The magnets 24 are arranged vertically in two rows of three on the left and right sides of the opposing surface 22c. The magnets 24 also have a shape in which the center of the front view is cut out in a roughly circular shape. The magnets 24 are detachably attached to the opposing surface 22c. The base portion 11 is made of aluminum, for example.

[0026] The bracket 12 comprises a vertical portion 31 connected to the base body portion 22 and the connecting portion 21, and a bracket body portion 32 protruding from the vertical portion 31. The bracket body portion 32 has a horizontal portion 34 that is perpendicular to the vertical portion 31 and extends horizontally. The connecting portion 21 and the bracket 12 are connected using a positioning jig 39. The positioning jig 39 uses a detachable fitting component (for example, a flex locator). The bracket 12 is made of aluminum, for example.

[0027] The torch moving unit 15 includes a pivot unit 16 rotatably supported on the base unit 11, and an articulated robot 13 rotatably supported on the pivot unit 16, with a welding torch 14 connected to its tip.

[0028] The pivot section 16 is mounted on the horizontal section 34 of the base section 11. As shown in Figure 3, the pivot section 16 comprises a pivot body 17 extending in the horizontal direction and a pivot drive section 18 that supports the pivot body 17 on the horizontal section 34 and rotates it.

[0029] The pivot body 17 is supported at one end by the horizontal section 34 of the base section 11 via the pivot drive unit 18. A horizontal plate section 37 for mounting the articulated robot 13 is attached to the other end. The horizontal plate section 37 is formed in a rectangular shape in plan view.

[0030] The horizontal plate portion 37 is positioned perpendicular to the vertical portion 31 of the bracket 12, and its upper surface is horizontal. A positioning jig 48 is provided on the horizontal plate portion 37, and the articulated robot 13 is connected to the pivot portion 16 in a positioned state using the positioning jig 48. The positioning jig 48 uses a detachable fitting component (for example, a flex locator).

[0031] The pivot body 17 is rotated horizontally by a pivot drive unit 18 at one end, around the first vertical axis L1. The pivot body 17 has sufficient rigidity to be rotated around the first vertical axis L1 when a load from the articulated robot 13 is applied to the other end.

[0032] The pivot body 17 rotates to move the articulated robot 13 in an arc shape around the first vertical axis L1 relative to the first side A1 of the welding target A. The pivot body 17 can adjust the position of the articulated robot 13 relative to the first side A1 by adjusting the amount of rotation. In other words, the pivot body 17 rotates around the first vertical axis L1, allowing the articulated robot 13 to be positioned so that it protrudes outward from the side edges on both sides in the width direction of the first side surface A1. In the pivot body 17 of this embodiment, by rotating around the first vertical axis L1, the second vertical axis L2, which is located at a position spaced apart from the first vertical axis L1, can be positioned so that it protrudes outward from the side edges on both sides in the width direction of the first side surface A1 of the object to be welded A.

[0033] The pivot drive unit 18 is installed on the horizontal section 34 of the base section 11 and rotates the pivot body 17 around a first vertical axis L1 that runs vertically. The pivot drive unit 18 rotates the pivot body 17 by controlling the amount of rotation using a servo motor or the like. The pivot drive unit 18 is installed in a state where it is housed inside the pivot body 17.

[0034] The articulated robot 13 comprises a main body 41 containing a control unit and drive unit mounted on a horizontal plate 37, and an arm 42 connected to the upper part of the main body 41. A power cord 43 extends from the main body 41. The arm 42 comprises a first arm 44 connected to the main body 41 and rotating about a second vertical axis L2 extending vertically, a second arm 45 as a base arm that rotates vertically relative to the first arm 44, and a third arm 46 and a fourth arm 47 as tip arm that rotate vertically relative to the second arm 45. The fourth arm 47 is rotatably connected to the third arm 46 and is rotatably connected to the third arm 46 about a rotation axis L3 along the third arm 46. A fifth arm 61 is provided at the tip of the fourth arm 47 and is rotatably connected to the fourth arm 47. The fifth arm portion 61 is provided with a sixth arm portion 62 that is rotatably connected to the fifth arm portion 61.

[0035] The welding torch 14 comprises a connecting member 51 connected to the sixth arm 62 of the articulated robot 13, and a torch body 52 attached to the connecting member 51. The connecting member 51 is detachably attached to the sixth arm 62. The torch body 52 is detachably attached to the connecting member 51. The tip of the welding torch 14 is positioned so as not to be offset in the left-right direction with respect to the rotation axis L3. However, the tip of the welding torch 14 may be positioned so as to be offset in the left-right direction with respect to the rotation axis L3. In this embodiment, the apparatus is configured to perform arc welding using a welding torch 14.

[0036] The welding torch 14 can perform welding while moving toward the first side A1 to the third side A3 by combining the movement of the pivot part 16 in the torch moving part 15 and the movement of the articulated robot 13. In this configuration, the welding torch 14 is configured to move in a desired orientation opposite each side A1, A2, and A3 so that an appropriate torch front-to-back angle and torch inclination angle can be obtained according to various conditions such as the shape of the welding area.

[0037] The welding apparatus 10 of this embodiment can perform welding while moving the tip of the welding torch 14 so that it faces the first side surface A1 in a desired orientation, by the operation of the pivot unit 16 and the articulated robot 13. This welding apparatus 10 can also perform welding on the second side surface A2 and the third side surface A3, respectively, while moving the tip of the welding torch 14 so that it faces them in the same desired orientation as the first side surface A1.

[0038] The method of using the welding apparatus 10 of this embodiment will now be described. As shown in Figure 2, the welding device 10 is attached to the steel column A to be welded. At this time, the opposing surface 22c on which the magnet 24 of the welding device 10 is positioned is placed opposite the first side surface A1 of the steel column A, and the welding device 10 is attached to the steel column A via the magnet 24 at a predetermined position. The welding device 10 is attached to the steel column A by the magnet 24 alone. The operator can make fine adjustments to the position of the welding device 10. Fine adjustments to the installation position of the welding device 10 are made by the operator moving the welding device 10 little by little while holding the handle 23 or the like.

[0039] Once the welding device 10 is positioned in the predetermined location, the welding operation begins. Welding is performed using a welding torch 14 connected to the tip of the articulated robot 13. For example, columns are joined together by welding the joint B of steel columns A. When welding the joint B around the entire circumference of steel column A, the welding device 10 may be reattached to opposite sides of steel column A for welding. Alternatively, two welding devices 10 may be attached to steel column A, with one welding device 10 performing welding for half the circumference of the column.

[0040] As shown in Figure 5(a), the pivot drive unit 18 positions the tip of the pivot unit 16 toward the second side A2, which is one side in the width direction of the first side A1, and the articulated robot 13 is positioned so as to protrude outward from the side edge of the first side A1. The first arm unit 44 to the sixth arm unit 62 of the arm unit 42 position the welding torch 14 toward the welding position on the second side A2, facing it in the desired orientation, to perform welding.

[0041] During welding, the pivot drive unit 18 and the first arm section 44 to the sixth arm section 62 are controlled to move the welding torch 14 in a desired orientation, according to the shape and orientation of the welding position. For example, when welding a joint B of a thick steel column A, the welding torch 14 is moved horizontally, for example, from an intermediate position on the second side A2 toward the side edge of the first side A1, while maintaining the welding torch 14 in the desired orientation.

[0042] As shown in Figure 5(b), in order to weld the welding position of the first side A1 after welding the second side A2, the welding apparatus 10 rotates the pivot section 16 around the second vertical axis L2 using the pivot drive section 18, thereby positioning the tip side away from the first side A1. The articulated robot 13 rotates the arm section 42 using the first arm section 44 and controls the movement of the first arm section 44 to the sixth arm section 62, thereby positioning the welding torch 14 facing the welding position of the first side A1 in the desired orientation and performing welding.

[0043] When welding the first side A1 following the second side A2, the boundary portion between the second side A2 and the first side A1 can also be welded in the same way by controlling the operation of the pivot drive unit 18 and the first arm portion 44 to the sixth arm portion 62 to be continuous.

[0044] As shown in Figure 5(c), after welding the first side A1, welding is performed at the welding position of the third side A3. The welding apparatus 10 rotates the pivot part 16 around the second vertical axis L2 by the pivot drive unit 18, so that the tip side is on the third side A3 side, which is the other side in the width direction of the first side A1, and the articulated robot 13 is positioned so that it protrudes outward from the side edge of the first side A1.

[0045] The first arm portion 44 to the sixth arm portion 62 of the arm portion 42 position the welding torch 14 opposite the welding position on the third side A3 in the desired orientation. At this time, the first arm portion 44 orients the arm portion 42 relative to the pivot portion 16 in the opposite direction to when welding the second side A2. The fourth arm portion 47 orients the welding torch 14 relative to the third arm portion 46 in the opposite direction to when welding the second side A2.

[0046] The articulated robot 13 rotates the arm 42 with the first arm 44 to control the movement of the second arm 45 to the sixth arm 62, thereby positioning the welding torch 14 facing the welding position on the third side A3 in the desired orientation and performing welding.

[0047] When welding the third side A3 following the first side A1, the boundary portion between the first side A1 and the third side A3 can also be welded in the same way by controlling the operation of the pivot drive unit 18 and the first arm portion 44 to the sixth arm portion 62 to be continuous.

[0048] Once welding work in a predetermined area is completed, the welding device 10 is moved to the next welding location. For example, it is moved to the opposite side of the first side A1 of the steel column A and the joint B on that side is welded. When moving the welding device 10, it can be easily removed because it is attached to the steel column A only by magnets 24. Also, because the welding device 10 is lightweight and compact, it can be easily moved and attached to a new location. Furthermore, because the welding device 10 is compact, it can be loaded onto construction elevators and easily transported even when moving between floors for welding work. By repeating this process, welding work can be carried out smoothly.

[0049] According to the welding apparatus 10 of this embodiment as described above, the pivot portion 16 rotates around the first vertical axis L1, allowing the articulated robot 13 to be positioned so that it protrudes outward from the side edge on both sides in the width direction of the first side surface A1. This allows the articulated robot 13 to be positioned in a location where it can perform welding work on the second side surface A2 and the third side surface A3, which are provided on both sides in the width direction of the first side surface A1.

[0050] In this position, the articulated robot 13 rotates around the second vertical axis L2, allowing the welding torch 14 to face the second side A2 and the third side A3, respectively. Therefore, the welding torch 14 can perform welding not only on the first side A1, but also on the second side A2 and the third side A3.

[0051] Since the base portion 11 that supports the torch movement portion 15 is attached to the first side A1 of the object to be welded A by a magnet 24, the welding device 10 does not require any effort to install. Moreover, since welding can be performed on the second side A2 and the third side A3 with the welding device 10 attached to the first side A1, there is no need to reattach the welding device 10 to each of the sides A1, A2, and A3.

[0052] Furthermore, because the articulated robot 13 is moved by the pivot section 16, the torch movement section 15 can be simply constructed, reducing the weight of the welding device. Therefore, even if the welding device 10 performs welding not only on the first side A1 but also on the second side A2 and the third side A3, it can be attached to the first side A1 by the magnet 24 and welding can be performed on each of the sides A1, A2, and A3, eliminating the need for complicated installation of the welding device 10.

[0053] In the welding apparatus 10 of this embodiment, the pivot portion 16 rotates around the first vertical axis L1, allowing the second vertical axis L2 to be positioned outside the side edge on both sides in the width direction of the first side surface. Therefore, the articulated robot 13 can rotate around a position outside the side edge on both sides in the width direction of the first side surface A1, making it easier to operate the connected welding torch 14 facing the second side surface A2 and the third side surface A3.

[0054] In the welding apparatus 10 of this embodiment, the welding torch 14 can be moved to face the first side surface A1 in a desired orientation while welding, and can also be moved to face the second side surface A2 and the third side surface A3 in a desired orientation while welding. Therefore, welding can be performed on each side surface A1, A2, and A3 with the same welding conditions, such as the torch's front-to-back angle and torch's inclination angle, making it easier to achieve equivalent welding quality on each surface.

[0055] In this embodiment, the articulated robot 13 is supported by a pivot section 16 via a first arm section 44 that is rotatable around a second vertical axis L2, and has a second arm section 45 that rotates vertically relative to the first arm section 44, third and fourth arm sections 46, 47 that are connected to a welding torch 14 and rotate vertically relative to the second arm section 45, and fifth and sixth arm sections 61, 62 that rotate relative to the fourth arm section 47, and the welding torch 14 is connected to the third and fourth arm sections 46, 47 so as to be rotatable around a rotation axis L3 within a range of half a turn or more.

[0056] Therefore, even if the second side A2 and the third side A3 are positioned facing opposite directions, when the articulated robot 13 moves the welding torch 14 to the opposing position on the second side A2 and the opposing position on the third side A3, it is easy to position the welding torch 14 facing each of the sides A1, A2, and A3 in the same direction.

[0057] Furthermore, in this embodiment, the welding torch 14 is equipped with fifth and sixth arm portions 61 and 62 that rotate relative to the fourth arm portion 47. Therefore, when the welding torch 14 is moved by the articulated robot 13, even if the angle of the rotation axis L3 extending from the third and fourth arm portions 46 and 47 with respect to each side A1, A2, and A3 is small, the tip of the welding torch 14 can be easily positioned to face each side A1, A2, and A3 in a desired orientation by rotating the fifth and sixth arm portions 61 and 62.

[0058] Although embodiments of the welding apparatus 10 according to the present invention have been described above, the present invention is not limited to the above embodiments and can be modified as appropriate without departing from the spirit of the invention.

[0059] For example, although the explanation used the example of a steel column with a rectangular horizontal cross-section for the welding target A, the welding target A may have a shape other than a rectangle, and may be a member other than a steel column. The welding device 10 can be used as appropriate for various members that have sides that are difficult to weld from one side.

[0060] Furthermore, although the welding apparatus 10 of this embodiment has been described as a welding apparatus capable of arc welding, it may also be a welding apparatus capable of gas welding or laser welding.

[0061] Furthermore, although this embodiment describes a welding apparatus 10 with six magnets, the number and placement of the magnets are arbitrary and can be set appropriately according to the weight of the welding apparatus 10.

[0062] Furthermore, although the welding apparatus 10 in this embodiment was configured to be attached to the steel column using only magnets, it may also be attached using other support and fixing methods in addition to magnets.

[0063] Furthermore, although the welding apparatus 10 of this embodiment has been described in the case where it is attached to a steel column for welding, the object to which it is attached may be a part other than a steel column, as long as it is the part where the welding work is performed.

[0064] Furthermore, in this embodiment, the welding apparatus 10 has the welding torches 14 facing each welding position on each side A1, A2, and A3 in the same orientation. However, the desired orientation of the welding torches 14 relative to the welding position on each side may differ, and welding may be performed with the welding torches 14 facing each other in different orientations.

[0065] Furthermore, although the welding apparatus 10 of this embodiment is configured to rotate the fourth arm portion 47 by a range of half a turn or more relative to the third arm portion 46, the configuration to change the protruding direction by rotating the welding torch 14 may be done by rotating other parts.

[0066] Furthermore, although the welding apparatus 10 of this embodiment has been described in an example in which the second arm portion 45 of the base arm portion and the third arm portion 46 of the tip arm portion are connected via a single joint, other arm portions or joints may be interposed between the base arm and the tip arm, as long as the welding apparatus 10 can be attached to the first side surface A1 by the magnet of the base portion 11 and operate within that range.

[0067] Furthermore, the "Sustainable Development Goals (SDGs)" are among the 17 international goals adopted at the UN Summit in September 2015. The structure moving device and structure moving method according to this embodiment can contribute to achieving some of the 17 SDGs, such as Goal 9, "Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation." [Explanation of symbols]

[0068] 10... Welding equipment 11…Base section 13… Articulated robots 14... Welding torch 15... Torch movement section 16…Pivot section 24…Magnets 42...Arm section 45...Second arm section (base end arm section) 46...Third arm section (tip arm section) 47…Fourth arm section (tip arm section) A... Welding target A1…First aspect A2...Second side A3...Third side L1…First vertical axis L2…Second vertical axis L3... Rotation axis

Claims

1. A base portion that is attached to the first side of the object to be welded by a magnet, The torch moving part is supported by the base portion, The welding torch is connected to the torch moving part, The torch moving part is, The base portion is supported so as to be rotatable about a first vertical axis, The system includes an articulated robot which is supported at a position spaced apart from the first vertical axis of the pivot portion so as to be rotatable about a second vertical axis, and has the welding torch connected to its tip, The pivot portion rotates about the first vertical axis, allowing the articulated robot to be positioned so that it protrudes outward from the side edges on both sides in the width direction of the first side surface. The articulated robot is a welding apparatus comprising an arm portion, the arm portion rotating about the second vertical axis, thereby moving the welding torch so that it faces the second and third sides, which are provided on both sides in the width direction of the first side, and welding can be performed.

2. The welding apparatus according to claim 1, wherein the pivot portion rotates about a first vertical axis, thereby enabling the second vertical axis to be positioned outside the side edge on both sides in the width direction of the first side surface.

3. The welding apparatus according to claim 1, wherein the welding torch is capable of welding while being moved in a desired orientation opposite to the first side surface, and is capable of welding while being moved in a desired orientation opposite to each of the second side surface and the third side surface.

4. The welding apparatus according to claim 3, wherein the arm portion of the articulated robot is supported by the pivot portion via a rotating portion that can rotate about the second vertical axis, and has a base arm portion that rotates vertically with respect to the rotating portion, and a tip arm portion that is connected to the welding torch and rotates vertically with respect to the base arm portion, and the welding torch is connected to the tip arm portion so as to be rotatable about the axis of rotation within a range of half a turn or more.

5. The welding apparatus according to claim 4, wherein the tip of the welding torch is positioned at an offset position with respect to the rotation axis.

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