Welding auxiliary device

Abstract

The utility model discloses an auxiliary welding device, which relates to the technical field of auxiliary tools and comprises a central rod, a first centering mechanism and a second centering mechanism. The lower end of the center rod is used for penetrating into a center hole of the flange plate and abutting against the table top, and the upper end of the center rod is used for penetrating into the straight pipe. The first centering mechanism is arranged at the lower end of the center rod and can be arranged in a center hole of the flange plate, and the first centering mechanism can abut against the inner wall of the center hole of the flange plate so that the axis of the center hole of the flange plate can coincide with the axis of the center rod. The second centering mechanism is arranged at the upper end of the center rod, the second centering mechanism can be arranged in the straight pipe, and the second centering mechanism can abut against the inner wall of the straight pipe so that the axis of the straight pipe can coincide with the axis of the center rod. According to the welding auxiliary device, welding personnel do not need to spend a lot of time to adjust the position between the flange plate and the straight pipe, and the welding efficiency of the flange plate and the straight pipe is improved.

Description

Technical Field

[0001] This utility model relates to the field of auxiliary tool technology, and in particular to a welding auxiliary device. Background Technology

[0002] Currently, in welding operations, it is often necessary to weld flanges and straight pipes together. During the actual welding process, welders need to repeatedly adjust the relative positions of the flange and straight pipe to ensure their axes coincide before welding can proceed. This repeated adjustment of the relative positions consumes a significant amount of the welder's time, thus hindering the efficiency of flange-to-straight-pipe welding. Utility Model Content

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a welding auxiliary device that improves the welding efficiency of flanges and straight pipes.

[0004] The welding auxiliary device according to an embodiment of the present invention includes a central rod, the lower end of which is inserted into the central hole of a flange and abuts against a table, and the upper end of which is inserted into a straight pipe; a first centering mechanism, which is disposed on the lower end of the central rod and can be disposed within the central hole of the flange, abutting against the inner wall of the central hole of the flange so that the axis of the central hole of the flange coincides with the axis of the central rod; and a second centering mechanism, which is disposed on the upper end of the central rod and above the first centering mechanism, and can be disposed within the straight pipe, abutting against the inner wall of the straight pipe so that the axis of the straight pipe coincides with the axis of the central rod.

[0005] It has at least the following beneficial effects:

[0006] When aligning the flange axis with the straight pipe axis, the welder first places the flange on a table, then inserts the lower end of the center rod and the first centering mechanism into the center hole of the flange. The welder then manipulates the first centering mechanism to abut against the inner wall of the flange's center hole. This first centering mechanism positions and adjusts the flange, ensuring the axis of the flange's center hole coincides with the axis of the center rod. After the flange is positioned and adjusted, the welder inserts the straight pipe into the upper end of the center rod and the second centering mechanism, abutting against the flange. The welder then manipulates the second centering mechanism to abut against the inner wall of the straight pipe. This second centering mechanism positions and adjusts the straight pipe, ensuring its axis coincides with the axis of the center rod, thus aligning the flange axis with the straight pipe axis. After the straight pipe is positioned and adjusted, the welder welds the straight pipe and flange together, completing the flange-straight pipe welding. After welding is completed, the welder can disengage the first centering mechanism from the flange and the second centering mechanism from the straight pipe. Finally, the center rod, the first centering mechanism, and the second centering mechanism can be removed from the flange and the straight pipe. This welding auxiliary device eliminates the need for welders to spend a lot of time adjusting the relative positions of the flange and the straight pipe, allowing the axis of the flange and the axis of the straight pipe to quickly align, thereby improving the welding efficiency of the flange and the straight pipe.

[0007] According to the welding auxiliary device of this utility model embodiment, the first centering mechanism includes a first base and a plurality of first adjusting arms. The first base is movably disposed on the central rod in the vertical direction. The upper ends of the plurality of first adjusting arms are all hinged to the first base. The plurality of first adjusting arms are circumferentially distributed along the axis of the central rod. The lower ends of the plurality of first adjusting arms can simultaneously abut against the tabletop. The descending first base can simultaneously drive the lower ends of the plurality of first adjusting arms away from each other, so that the lower ends of the plurality of first adjusting arms can simultaneously abut against the inner wall of the center hole of the flange, and make the axis of the center hole of the flange coincide with the axis of the central rod.

[0008] According to the welding auxiliary device of this utility model embodiment, the first centering mechanism further includes a first nut, a first through hole is provided on the first base for the center rod to pass through, a first external thread is provided on the outer wall of the lower end of the center rod, the first nut is provided on the upper end of the first base, the threaded hole of the first nut communicates with the first through hole, and the first nut is threadedly connected to the first external thread so that the first nut can drive the first base to move in the up and down direction.

[0009] According to the welding auxiliary device of this utility model embodiment, each of the lower ends of the plurality of first adjusting arms is provided with a first rounded corner, and the plurality of first adjusting arms abut against the table through the first rounded corner.

[0010] According to an embodiment of the welding auxiliary device of this utility model, the second centering mechanism includes a second base, a disc, and a plurality of second adjusting arms. The second base is movably mounted on the central rod in the vertical direction. The lower ends of the plurality of second adjusting arms are all hinged to the second base. The plurality of second adjusting arms are circumferentially distributed along the axis of the central rod. The axis of the disc coincides with the axis of the central rod. The disc is movably mounted on the central rod in the vertical direction. The disc is located within the area enclosed by the plurality of second adjusting arms. The disc can simultaneously abut against the plurality of second adjusting arms, so that the upper ends of the plurality of second adjusting arms can move away from each other and simultaneously abut against the inner wall of the straight pipe, and so that the axis of the straight pipe coincides with the axis of the central rod.

[0011] According to the welding auxiliary device of this utility model embodiment, the second centering mechanism further includes a second nut, a second through hole is provided on the second base for the center rod to pass through, a second external thread is provided on the outer wall of the upper end of the center rod, the second nut is provided on the lower end of the second base, the threaded hole of the second nut communicates with the second through hole, and the second nut is threadedly connected to the second external thread so that the second nut can drive the second base to move in the up and down direction.

[0012] According to the welding auxiliary device of this utility model embodiment, the disc is provided with a threaded sleeve, and the threaded sleeve is threadedly connected to the second external thread.

[0013] According to the welding auxiliary device of this utility model embodiment, the lower ends of the plurality of second adjusting arms are provided with second rounded corners, and the lower ends of the plurality of second adjusting arms abut against the inner wall of the straight pipe through the second rounded corners.

[0014] The welding auxiliary device according to an embodiment of the present utility model further includes a foot pad, which is disposed on the lower end of the central rod. The lower end of the central rod abuts against the tabletop through the foot pad to increase the contact area between the central rod and the tabletop.

[0015] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0017] Figure 1 This is a schematic diagram of the flange and straight pipe in an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of the flange, straight pipe, and welding auxiliary device according to an embodiment of the present utility model;

[0019] Figure 3 This is a schematic diagram of the flange and welding auxiliary device according to an embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of the welding auxiliary device according to an embodiment of the present invention;

[0021] Figure 5 This is a top view schematic diagram of the welding auxiliary device according to an embodiment of the present invention;

[0022] Icon labels:

[0023] First centering mechanism 100; First base 110; First adjusting arm 120; First fillet 121; First nut 130;

[0024] Second centering mechanism 200; second base 210; second adjusting arm 220; second fillet 221; second nut 230; disc 240; threaded sleeve 241;

[0025] Center rod 300; Foot pads 310;

[0026] Flange 10; Straight pipe 20. Detailed Implementation

[0027] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0028] In the description of this utility model, the use of "first" and "second" is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features or the order of the technical features.

[0029] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0030] Reference Figures 1 to 3This utility model discloses a welding auxiliary device, including a center rod 300, a first centering mechanism 100 and a second centering mechanism 200.

[0031] The lower end of the center rod 300 is used to pass through the center hole of the flange 10 and abut against the table surface, while the upper end of the center rod 300 is used to pass through the straight pipe 20. A first centering mechanism 100 is located on the lower end of the center rod 300. The first centering mechanism 100 can be located within the center hole of the flange 10 and abut against the inner wall of the center hole of the flange 10, so that the axis of the center hole of the flange 10 coincides with the axis of the center rod 300. A second centering mechanism 200 is located on the upper end of the center rod 300, above the first centering mechanism 100. The second centering mechanism 200 can be located within the straight pipe 20 and abut against the inner wall of the straight pipe 20, so that the axis of the straight pipe 20 coincides with the axis of the center rod 300.

[0032] Understandably, when it's necessary to align the axis of flange 10 with the axis of straight pipe 20, the welder can first place flange 10 on a table, then insert the lower end of center rod 300 and the first centering mechanism 100 together into the center hole of flange 10. The welder can then manipulate the first centering mechanism 100 to abut against the inner wall of the center hole of flange 10. At this point, the first centering mechanism 100 provides positioning and adjustment for flange 10, ensuring that the axis of the center hole of flange 10 coincides with the axis of center rod 300. After the flange 10 is positioned and adjusted, the welder can insert the straight pipe 20 onto the upper end of center rod 300 and the second centering mechanism 200, abutting the straight pipe 20 against flange 10. The welder can then manipulate the second centering mechanism 200 to abut against the inner wall of the straight pipe 20. At this point, the second centering mechanism 200 positions and adjusts the straight pipe 20, ensuring that the axis of the straight pipe 20 coincides with the axis of the center rod 300, thereby aligning the axis of the flange 10 with the axis of the straight pipe 20. After the straight pipe 20 is positioned and adjusted, the welder welds the straight pipe 20 and the flange 10 together, completing the welding of the flange 10 and the straight pipe 20. After welding, the welder can disengage the first centering mechanism 100 from the flange 10 and the second centering mechanism 200 from the straight pipe 20. Finally, the center rod 300, the first centering mechanism 100, and the second centering mechanism 200 can be removed from the flange 10 and the straight pipe 20. This welding auxiliary device eliminates the need for welders to spend a significant amount of time adjusting the relative positions of the flange 10 and the straight pipe 20, allowing the axes of the flange 10 and the straight pipe 20 to quickly align, thus improving the welding efficiency of the flange 10 and the straight pipe 20.

[0033] refer to Figures 2 to 4The first centering mechanism 100 includes a first base 110 and a plurality of first adjusting arms 120. The first base 110 is movably mounted on the central rod 300 in the vertical direction. The upper ends of the plurality of first adjusting arms 120 are all hinged to the first base 110. The plurality of first adjusting arms 120 are circumferentially distributed along the axis of the central rod 300. The lower ends of the plurality of first adjusting arms 120 can simultaneously abut against the table. The descending first base 110 can simultaneously drive the lower ends of the plurality of first adjusting arms 120 away from each other, so that the lower ends of the plurality of first adjusting arms 120 can simultaneously abut against the inner wall of the central hole of the flange 10, and make the axis of the central hole of the flange 10 coincide with the axis of the central rod 300.

[0034] Understandably, when positioning and adjusting the flange 10, the welder can first place the flange 10 on a table, then insert the lower ends of the center rod 300 and the multiple first adjusting arms 120 into the center hole of the flange 10, so that the lower ends of the center rod 300 and the multiple first adjusting arms 120 simultaneously abut against the table, at which point the multiple first adjusting arms 120 are in an expanded state. The welder then holds the center rod 300 to ensure it does not move relative to the table. Next, the welder moves the first base 110 downwards. Since the upper ends of the multiple first adjusting arms 120 are hinged to the first base 110, and the lower ends of the multiple first adjusting arms 120 are abutting against the table, under the downward pushing force of the first base 110, the multiple first adjusting arms 120 begin to swing synchronously, causing the lower ends of the multiple first adjusting arms 120 to move away from each other while remaining abutting against the table, thus allowing the lower ends of the multiple first adjusting arms 120 to press firmly against the inner wall of the center hole of the flange 10. As the lower ends of the multiple first adjusting arms 120 press against the inner wall of the center hole of the flange 10, the flange 10 begins to move under the action of the first adjusting arms 120, allowing the axis of the center hole of the flange 10 to gradually approach the axis of the center rod 300. When the lower ends of the multiple first adjusting arms 120 are fully pressed against the inner wall of the center hole of the flange 10, the axis of the center hole of the flange 10 coincides with the axis of the center hole, thus completing the positioning adjustment of the flange 10. In this embodiment of the invention, the number of first adjusting arms 120 is three or more.

[0035] refer to Figures 2 to 4The first centering mechanism 100 also includes a first nut 130. A first through hole is provided on the first base 110 for the center rod 300 to pass through. A first external thread is provided on the outer wall of the lower end of the center rod 300. The first nut 130 is located on the upper end of the first base 110. The threaded hole of the first nut 130 communicates with the first through hole, and the first nut 130 is threadedly connected to the first external thread, so that the first nut 130 can drive the first base 110 to move vertically. It can be understood that the first through hole communicating with the threaded hole of the first nut 130 is provided on the first base 110, and the center rod 300 passes through the first through hole and the first nut 130. The first nut 130 is rotatably connected to the upper end of the first base 110, and the first nut 130 is threadedly connected to the first external thread on the outer wall of the lower end of the center rod 300. When the first base 110 needs to be lowered, the welder can tighten the first nut 130, causing the first nut 130 to lower the first base 110 and the multiple first adjusting arms 120 on the first base 110. When the next flange 10 needs to be positioned and adjusted, the welder can tighten the first nut 130, causing the first nut 130 to raise the first base 110 and the multiple first adjusting arms 120 on the first base 110, thereby causing the lower ends of the multiple first adjusting arms 120 to retract, so that the welder can insert the center rod 300 and the lower ends of the multiple first adjusting arms 120 into the center hole of the next flange 10.

[0036] refer to Figure 4 Each of the multiple first adjusting arms 120 has a first rounded corner 121 at its lower end, and the multiple first adjusting arms 120 abut against the table surface through the first rounded corner 121. It can be understood that during the descent of the first base 110, the lower ends of the multiple first adjusting arms 120 remain abutted against the table surface through the first rounded corner 121, so that the lower ends of the multiple first adjusting arms 120 can move smoothly on the table surface, thereby reducing wear between the first adjusting arms 120 and the table surface.

[0037] refer to Figure 2 , Figure 4 and Figure 5The second centering mechanism 200 includes a second base 210, a disc 240, and a plurality of second adjusting arms 220. The second base 210 is movably mounted on the central rod 300 in the vertical direction. The lower ends of the plurality of second adjusting arms 220 are all hinged to the second base 210. The plurality of second adjusting arms 220 are circumferentially distributed along the axis of the central rod 300. The axis of the disc 240 coincides with the axis of the central rod 300. The disc 240 is movably mounted on the central rod 300 in the vertical direction. The disc 240 is located within the area enclosed by the plurality of second adjusting arms 220. The disc 240 can simultaneously abut against the plurality of second adjusting arms 220, so that the upper ends of the plurality of second adjusting arms 220 can move away from each other and simultaneously abut against the inner wall of the straight tube 20, and so that the axis of the straight tube 20 coincides with the axis of the central rod 300.

[0038] Understandably, after the flange 10 is positioned and adjusted, the welder can insert the straight pipe 20 onto the upper end of the center rod 300 and the multiple second adjusting arms 220, so that the straight pipe 20 rests against the flange 10. Since the lower ends of the multiple second adjusting arms 220 are all hinged to the second base 210, the upper ends of the multiple second adjusting arms 220 can simultaneously rest against the inner wall of the straight pipe 20 under their own weight. Then the welder holds the center rod 300 to ensure that the center rod 300 does not move relative to the table. Then the welder can move the disc 240 downward so that the disc 240 can simultaneously rest against the multiple second adjusting arms 220. The welder continues to move the disc 240 downward, and under the downward pushing force of the disc 240, the multiple second adjusting arms 220 begin to expand, so that the upper ends of the multiple second adjusting arms 220 can simultaneously press against the inner wall of the straight pipe 20. As the upper ends of the multiple second adjusting arms 220 press against the inner wall of the straight pipe 20, the straight pipe 20 begins to move under the action of the second adjusting arms 220, allowing the axis of the straight pipe 20 to gradually approach the axis of the central rod 300. When the upper ends of the multiple second adjusting arms 220 are fully pressed against the inner wall of the straight pipe 20, the axis of the straight pipe 20 coincides with the axis of the central hole, thus completing the positioning and adjustment of the straight pipe 20. At this point, the axis of the straight pipe 20 coincides with the axis of the flange 10, allowing the welder to weld the flange 10 and the straight pipe 20 together. In this embodiment of the invention, the number of second adjusting arms 220 is three or more.

[0039] refer to Figure 3 and Figure 4The second centering mechanism 200 also includes a second nut 230. A second through hole is provided on the second base 210 for the center rod 300 to pass through. A second external thread is provided on the outer wall of the upper end of the center rod 300. The second nut 230 is located on the lower end of the second base 210. The threaded hole of the second nut 230 communicates with the second through hole, and the second nut 230 is threadedly connected to the second external thread, so that the second nut 230 can drive the second base 210 to move vertically. It can be understood that the second base 210 has a second through hole communicating with the threaded hole of the second nut 230, and the center rod 300 passes through the second through hole and the second nut 230. The second nut 230 is rotatably connected to the lower end of the second base 210, and the second nut 230 is threadedly connected to the second external thread on the outer wall of the upper end of the center rod 300. When it is necessary to raise or lower the second base 210, the welder can tighten the second nut 230 to move the second base 210 vertically on the central rod 300, thereby adjusting the position of the second base 210 and the multiple second adjusting arms 220 on the central rod 300 to accommodate straight pipes 20 of different lengths. (Reference) Figure 5 A threaded sleeve 241 is provided on the disc 240, and the threaded sleeve 241 is threadedly connected to the second external thread. It can be understood that the axis of the threaded sleeve 241 on the disc 240 coincides with the axis of the central rod 300, and the threaded sleeve 241 is threadedly connected to the second external thread at the upper end of the central rod 300. The welder can move the disc 240 vertically on the central rod 300 by rotating the threaded sleeve 241 and the disc 240. (Reference) Figure 4 Each of the lower ends of the multiple second adjusting arms 220 is provided with a second rounded corner 221, and the lower ends of the multiple second adjusting arms 220 abut against the inner wall of the straight tube 20 through the second rounded corner 221. It can be understood that the second rounded corner 221 can prevent the lower ends of the second adjusting arms 220 from scratching the inner wall of the straight tube 20.

[0040] After the welder welds the flange 10 and the straight pipe 20 together, the welder can rotate the threaded sleeve 241 and the disc 240, causing the disc 240 to rise and disengage from the contact with the multiple second adjusting arms 220. At this time, the pressure between the upper ends of the multiple second adjusting arms 220 and the inner wall of the straight pipe 20 decreases. Then the welder moves the flange 10 off the table, at which point the lower ends of the multiple first adjusting arms 120 will retract under their own weight and disengage from the contact with the inner wall of the center hole of the flange 10. Finally, the welder can pull the welding auxiliary device out of the flange 10 and the straight pipe 20.

[0041] refer to Figure 3 and Figure 4The welding auxiliary device also includes a foot pad 310, which is located on the lower end of the central rod 300. The lower end of the central rod 300 abuts against the table surface via the foot pad 310, thereby increasing the contact area between the central rod 300 and the table surface. It is understood that the foot pad 310 increases the contact area between the central rod 300 and the table surface, allowing the central rod 300 to rest stably against the table surface, thus preventing the central rod 300 from moving relative to the table surface.

[0042] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0043] Of course, this utility model is not limited to the above-described embodiments. Those skilled in the art can make equivalent modifications or substitutions without departing from the spirit of this utility model. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A welding aid, characterized in that The utility model relates to a centering mechanism for a table, comprising: a center rod (300), the lower end of the center rod (300) is used for being arranged in the center hole of the flange plate (10) and abutting against the tabletop, the upper end of the center rod (300) is used for being arranged in the straight pipe (20); a first centering mechanism (100), the first centering mechanism (100) is arranged on the lower end of the center rod (300), the first centering mechanism (100) can be arranged in the center hole of the flange plate (10), the first centering mechanism (100) can abut against the inner wall of the center hole of the flange plate (10) to make the axis of the center hole of the flange plate (10) coincide with the axis of the center rod (300); a second centering mechanism (200), the second centering mechanism (200) is arranged on the upper end of the center rod (300), the second centering mechanism (200) is arranged above the first centering mechanism (100), the second centering mechanism (200) can be arranged in the straight pipe (20), the second centering mechanism (200) can abut against the inner wall of the straight pipe (20) to make the axis of the straight pipe (20) coincide with the axis of the center rod (300).

2. The welding aid of claim 1, wherein: The first centering mechanism (100) comprises a first base (110) and a plurality of first adjusting arms (120), the first base (110) is movably arranged on the center rod (300) in the up-down direction, the upper ends of the plurality of first adjusting arms (120) are hingedly connected to the first base (110), the plurality of first adjusting arms (120) are circumferentially distributed along the axis of the center rod (300), the lower ends of the plurality of first adjusting arms (120) can simultaneously abut against the tabletop, the descending first base (110) can simultaneously drive the lower ends of the plurality of first adjusting arms (120) to move away from each other, so that the lower ends of the plurality of first adjusting arms (120) can simultaneously abut against the inner wall of the center hole of the flange plate (10), and the axis of the center hole of the flange plate (10) coincides with the axis of the center rod (300).

3. The welding aid of claim 2, wherein: The first centering mechanism (100) further comprises a first nut (130), a first through hole is formed in the first base (110) for the center rod (300) to pass through, a first external thread is arranged on the outer wall of the lower end of the center rod (300), the first nut (130) is arranged on the upper end of the first base (110), the threaded hole of the first nut (130) is in communication with the first through hole, and the first nut (130) is threadedly connected with the first external thread, so that the first nut (130) can drive the first base (110) to move in the up-down direction.

4. The welding aid of claim 2, wherein: First round corners (121) are arranged on the lower ends of the plurality of first adjusting arms (120), and the plurality of first adjusting arms (120) abut against the tabletop through the first round corners (121).

5. The welding aid of claim 1, wherein: The second centering mechanism (200) comprises a second base (210), a disc (240) and a plurality of second adjusting arms (220), the second base (210) is movably arranged on the central rod (300) along the up-down direction, the lower ends of the plurality of second adjusting arms (220) are hingedly connected to the second base (210), the plurality of second adjusting arms (220) are circumferentially distributed along the axis of the central rod (300), the axis of the disc (240) coincides with the axis of the central rod (300), the disc (240) is movably arranged on the central rod (300) along the up-down direction, the disc (240) is arranged in the area surrounded by the plurality of second adjusting arms (220), the disc (240) can simultaneously abut against the plurality of second adjusting arms (220), so that the upper ends of the plurality of second adjusting arms (220) can move away from each other and simultaneously abut against the inner wall of the straight pipe (20), and the axis of the straight pipe (20) coincides with the axis of the central rod (300).

6. The welding aid of claim 5, wherein: The second centering mechanism (200) further comprises a second nut (230), a second through hole is formed in the second base (210), the second through hole is used for passing the central rod (300), a second external thread is arranged on the outer wall of the upper end of the central rod (300), the second nut (230) is arranged on the lower end of the second base (210), the threaded hole of the second nut (230) is in communication with the second through hole, and the second nut (230) is threadedly connected with the second external thread, so that the second nut (230) can drive the second base (210) to move along the up-down direction.

7. The welding aid of claim 6, wherein: The disc (240) is provided with a threaded sleeve (241), and the threaded sleeve (241) is threadedly connected with the second external thread.

8. The welding aid of claim 5, wherein: The lower end of each of the plurality of second adjusting arms (220) is provided with a second round corner (221), and the lower end of each of the plurality of second adjusting arms (220) abuts against the inner wall of the straight pipe (20) through the second round corner (221).

9. The welding aid of claim 1, wherein: A foot pad (310) is further arranged on the lower end of the central rod (300), and the lower end of the central rod (300) abuts against the tabletop through the foot pad (310), so as to increase the contact area between the central rod (300) and the tabletop.

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