Automatic gas shielded welding device for longitudinal seam in steel pipe cavity

Abstract

The invention discloses an automatic gas shielded welding device for a longitudinal seam in a steel pipe cavity, the automatic gas shielded welding device comprises a base mechanism and a side mounting mechanism, a guide mechanism is arranged above the base mechanism, and a welding mechanism is mounted in the guide mechanism. According to the welding device, the gear and the rack are arranged and matched with the pressing plate, during use, the welding head can be driven to move through rotation of the gear, so that a longitudinal seam in a steel pipe cavity is welded, the steel pipe can be conveniently rotated and the longitudinal seam is adjusted to the lowermost portion through arrangement of the supporting roller when the steel pipe is placed on the base mechanism, and in this way, the welding efficiency is improved. The steel pipe longitudinal seam welding device is simple in structure and convenient to use, excessive constraint is not needed during prevention, adjustment is convenient, in this way, in the welding process, the longitudinal seam of a steel pipe can be welded through the welding head only by controlling starting and stopping of the driving motor and power control to adjust the moving speed, manual entering is not needed, damage to the human body is reduced to the maximum extent, and welding safety is improved.

Description

Technical Field

[0001] The invention relates to the technical field of steel pipe welding, in particular to an automatic gas shielded welding device for longitudinal seams in a steel pipe cavity. Background Art

[0002] Steel pipe is a steel material with a hollow cross section and a length much larger than its diameter or circumference. According to the cross-sectional shape, it can be divided into round, square, rectangular and special-shaped steel pipes; according to the material, it can be divided into carbon structural steel pipes, low alloy structural steel pipes, alloy steel pipes and composite steel pipes; according to the purpose, it can be divided into steel pipes for transportation pipelines, engineering structures, thermal equipment, petrochemical industry, machinery manufacturing, geological drilling, high-pressure equipment, etc. For steel pipes with larger thickness and diameter, their longitudinal seams need to be welded. At present, most of the welding is to weld the longitudinal seams on the outside of the steel pipe first, and then manually enter the steel pipe to weld the longitudinal seams in the cavity.

[0003] In the prior art, steel pipes are mostly welded by gas shielded welding. When the longitudinal seam in the steel pipe cavity is welded by gas shielded welding, the gas generated will cause damage to the human respiratory tract, and the gas in the cavity is not easy to dissipate. At the same time, gas shielded welding also requires the gas for protection, which makes this welding method more harmful. Summary of the invention

[0004] The purpose of the present invention is to provide an automatic gas shielded welding device for longitudinal seams in steel pipe cavities, so as to solve the problem that the welding of steel pipes proposed in the above-mentioned background technology is mostly carried out by gas shielded welding. When the longitudinal seams in the steel pipe cavities are welded by gas shielded welding, the gas generated will cause damage to the human respiratory tract, and the gas in the cavity is not easy to dissipate. At the same time, gas shielded welding also requires the gas for protection, which leads to the problem that the welding method is more harmful.

[0005] To achieve the above object, the present invention provides the following technical solution: an automatic gas shielded welding device for longitudinal seams in a steel pipe cavity, comprising a base mechanism, the base mechanism and a side mounting mechanism, a guide mechanism is arranged above the base mechanism, and a welding mechanism is installed inside the guide mechanism; The base mechanism includes a horizontal frame, a support roller is arranged at the upper end of the horizontal frame, the horizontal frames are symmetrically arranged, and a vertical frame is fixedly connected between two adjacent horizontal frames. The side mounting mechanism is arranged on both sides of the base mechanism, and the side mounting mechanism includes a side mounting frame, and both sides of the middle part of the side mounting frame are fixedly connected with a hydraulic cylinder; The guiding mechanism comprises an L-shaped connecting plate, the number of the L-shaped connecting plates is two, the welding mechanism comprises a pressing plate, one of the L-shaped connecting plates is fixedly connected to a No. 2 side frame on both sides of the middle of one side, the other of the L-shaped connecting plates is fixedly connected to a No. 1 side frame on both sides of the middle of one side, a No. 2 expansion frame is arranged between the No. 1 side frame and the No. 2 side frame, the No. 2 expansion frame, the No. 1 side frame and the No. 2 side frame are fixedly connected to a rack at the lower middle of one side, the four corners below the pressing plate are rotatably connected to gears, and one side of the upper end of the pressing plate is fixedly connected to A reducer is connected, and a drive motor is fixedly connected to the upper end of the reducer. The output end of the drive motor is fixedly connected to the input shaft of the reducer. The output shaft of the reducer passes through a pressure plate and is fixedly connected to the shaft of one of the gears. The gear is meshed with a rack. A welding head is installed on one side of the pressure plate. The number of the cross frame and the second extension frame is set according to the length of the welded steel pipe required. A gap is left between one side of the built-in block and the side of the cross frame. One end face of the extension block is a protruding design, and the protruding length is equal to the length between the side of the built-in block and the side of the cross frame.

[0006] Preferably, a No. 1 reinforcing rib is fixedly connected to the interior of the cross frame, a built-in block is fixedly connected to one end of the cross frame, and an extension block is fixedly connected to the other end of the cross frame, and a No. 1 connecting hole is provided in the interior of the extension block and the built-in block and on both sides of the side mounting frame.

[0007] Preferably, clamping plates are fixedly connected to both sides of the middle of one side of the side mounting frame, and mounting plates are fixedly connected to the upper and lower ends of the hydraulic cylinder, and the mounting plate is fixedly connected to the side mounting frame.

[0008] Preferably, the middle part and both sides of the middle part of the side mounting frame are fixedly connected with No. 2 reinforcing ribs, the output end of the hydraulic cylinder is fixedly connected with an insertion rod, the insertion rod is plugged into the L-shaped connecting plate, and the other side of the upper end of the pressure plate is fixedly connected with a No. 2 support frame, and a No. 1 through hole is opened inside the No. 2 support frame, and a No. 2 through hole is opened on one side of the middle part of one of the L-shaped connecting plates.

[0009] Preferably, a bottom plate is provided below the pressure plate, a connecting plate is fixedly connected between the upper end of the bottom plate and the pressure plate, limiting strips are fixedly connected to both sides of the middle part of the upper end of the bottom plate, and rollers are rotatably connected to both sides of the middle part of the pressure plate.

[0010] Preferably, a No. 1 slot is provided at the upper end of the rack, a No. 2 slot is provided at the lower end of the rack, the lower end of the roller is located in the No. 1 slot, and the No. 2 slot is slidably connected to the limit bar.

[0011] Preferably, an extension plate is fixedly connected to the lower middle portion of one side of the No. 2 expansion frame, the No. 1 side frame and the No. 2 side frame, and end blocks are fixedly connected to both sides of the upper end of the extension plate.

[0012] Preferably, a dovetail groove is provided on one side of one of the end blocks, a dovetail block is fixedly connected to one side of the other end block, a through hole is provided inside the end block, and a bottom support block is fixedly connected to the lower end of the extension plate.

[0013] Preferably, a No. 1 support frame is fixedly connected to both sides of the middle of the upper end of the horizontal frame, and a connecting shaft is fixedly connected to both ends of the support roller.

[0014] Preferably, the interior of the No. 1 support frame is fixedly connected to the No. 1 expansion frame, and the connecting shaft overlaps the No. 1 support frame.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. In the present invention, by setting the gear and the rack, in cooperation with the pressure plate, when in use, the rotation of the gear can drive the welding head to move, so as to weld the longitudinal seam in the steel pipe cavity. By setting the supporting roller, when the steel pipe is placed on the base mechanism, the steel pipe can be easily rotated and the longitudinal seam can be adjusted to the lowest position. In this way, there is no need for excessive constraints during prevention, and adjustment is convenient for use. In this way, when welding, it is only necessary to control the start and stop and power control of the drive motor to adjust the moving speed, and the longitudinal seam of the steel pipe can be welded by the welding head without manual entry, so as to minimize damage to the human body and increase welding safety.

[0016] 2. In the present invention, the groove formed by the internal block and the cross frame and the cooperation of the extended block are used to perform preliminary limiting during installation, which is convenient for the connection of the No. 1 connecting hole, thereby facilitating the installation of the bolts and making the installation more convenient. The No. 1 reinforcing rib and the No. 2 reinforcing rib are provided to ensure the strength of the cross frame and the side mounting frame respectively. The connection between the connecting shaft and the No. 1 support frame does not use the rotation connection of the bearing, but adopts a direct overlap method to facilitate installation and subsequent replacement and maintenance. On the other hand, it will not affect the rotation use, and only needs to apply lubricating oil. The No. 1 expansion frame is provided to increase the supporting strength of the connecting shaft.

[0017] 3. In the present invention, the plug-in rod is provided to connect with the L-shaped connecting plate in a plug-in manner instead of direct fixation. When in use, the No. 2 expansion frame, the No. 1 side frame and the No. 2 side frame can be placed on the inner wall of the steel pipe to avoid bending of the connection between the No. 1 side frame, the No. 2 side frame and the No. 2 expansion frame to cause damage, thereby ensuring the service life of the guide mechanism and reducing damage. By driving in an engaging manner, the movement accuracy is higher. The No. 1 through hole and the No. 2 through hole are provided to support the welding rod and the wire of the gas shielded welding. The welding rod and the wire are supported on the surface of the extension plate to avoid the phenomenon that when the steel pipe is long, the middle part of the line is pressed down due to the weight and contacts the surface of the steel pipe, causing the high welding temperature to damage the skin of the wire, thereby ensuring the safety of use. The roller is provided to make the movement smoother.

[0018] 4. In the present invention, by setting the bottom support block, according to the different inner diameters of the welded steel pipes, the bottom surface of the bottom support block is set with different curvatures to fit and support the inner wall of the steel pipe to ensure stability in use. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The three-dimensional structure of the automatic gas shielded welding device for longitudinal seam in steel pipe cavity of the present invention is shown in FIG. Figure 1 ; Figure 2 The three-dimensional structure of the automatic gas shielded welding device for longitudinal seam in steel pipe cavity of the present invention is shown in FIG. Figure 2 ; Figure 3 It is a three-dimensional structural schematic diagram of a base mechanism in a steel pipe lumen longitudinal seam automatic gas shielded welding device of the present invention; Figure 4 This invention is a kind of automatic gas shielded welding device for longitudinal seam in steel pipe cavity Figure 3 A schematic diagram of the enlarged structure of the middle A area; Figure 5 It is a schematic diagram of the connection state of the welding mechanism and the guiding mechanism in the automatic gas shielded welding device for longitudinal seams in a steel pipe cavity of the present invention; Figure 6 It is a schematic diagram of the explosion structure of the side loading mechanism in the automatic gas shielded welding device for longitudinal seams in a steel pipe cavity of the present invention; Figure 7 It is a partial structural schematic diagram of a guide mechanism in an automatic gas shielded welding device for longitudinal seams in a steel pipe cavity of the present invention; Figure 8 The present invention is a partial structural schematic diagram of a welding mechanism in an automatic gas shielded welding device for longitudinal seams in a steel pipe cavity.

[0020] In the figure: 1. Base mechanism; 11. Horizontal frame; 12. No. 1 reinforcing rib; 13. Support roller; 14. Extension block; 15. Internal block; 16. No. 1 connecting hole; 17. Vertical frame; 18. Connecting shaft; 19. No. 1 supporting frame; 110. No. 1 expansion frame; 2. Guide mechanism; 21. No. 2 expansion frame; 22. No. 1 side frame; 23. No. 2 side frame; 24. Bottom support block; 25. L-shaped connecting plate; 26. Through hole; 27. Extension plate; 28. End block; 29. ​​Dovetail block; 210. Dovetail groove; 3. Welding mechanism; 31. Driving motor; 32. Speed ​​reducer; 33. Pressing plate; 34. No. 2 support frame; 35. No. 1 through hole; 36. No. 2 through hole; 37. Welding head; 38. Rack; 39. No. 1 notch; 310. No. 2 notch; 311. Gear; 312. Bottom plate; 313. Connecting plate; 314. Roller; 315. Limiting strip; 4. Side mounting mechanism; 41. Side mounting frame; 42. Hydraulic cylinder; 43. Insert rod; 44. No. 2 reinforcing rib; 45. Mounting plate; 46. Clamp plate. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the implementation regulations described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] Embodiment 1 Reference Figure 1 - Figure 8 As shown: an automatic gas shielded welding device for longitudinal seams in a steel pipe cavity, comprising a base mechanism 1, a base mechanism 1 and a side mounting mechanism 4, a guide mechanism 2 is arranged above the base mechanism 1, and a welding mechanism 3 is installed inside the guide mechanism 2; The base mechanism 1 includes a horizontal frame 11, and a support roller 13 is arranged at the upper end of the horizontal frame 11. The horizontal frames 11 are symmetrically arranged, and a vertical frame 17 is fixedly connected between two adjacent horizontal frames 11. The side mounting mechanism 4 is arranged on both sides of the base mechanism 1, and the side mounting mechanism 4 includes a side mounting frame 41. Both sides of the middle part of the side mounting frame 41 are fixedly connected with a hydraulic cylinder 42. The guiding mechanism 2 includes an L-shaped connecting plate 25, the number of which is two, and the welding mechanism 3 includes a pressing plate 33, wherein the middle of one side of the L-shaped connecting plate 25 is fixedly connected to the second side frame 23 on both sides, and the middle of the other side of the L-shaped connecting plate 25 is fixedly connected to the first side frame 22 on both sides, and the second expansion frame 21 is arranged between the first side frame 22 and the second side frame 23, and the middle of the second expansion frame 21, the first side frame 22 and the second side frame 23 are fixedly connected to the rack 38 at the lower part, the four corners below the pressing plate 33 are rotatably connected to the gear 311, and the upper end of the pressing plate 33 is fixedly connected to the reducer 3 2. The upper end of the reducer 32 is fixedly connected with a driving motor 31, and the output end of the driving motor 31 is fixedly connected with the input shaft of the reducer 32. The output shaft of the reducer 32 passes through the pressure plate 33 and is fixedly connected with the shaft of one of the gears 311. The gear 311 is meshed with the rack 38. A welding head 37 is installed on one side of the pressure plate 33. The number of the cross frame 11 and the second extension frame 21 is set according to the length of the welded steel pipe as required. A gap is left between one side of the built-in block 15 and the side of the cross frame 11. One end face of the extension block 14 is a protruding design, and the protruding length is equal to the length between the side of the built-in block 15 and the side of the cross frame 11.

[0023] In the present invention, by setting the gear 311 and the rack 38, in cooperation with the pressure plate 33, when in use, the rotation of the gear 311 can drive the welding head 37 to move, so as to weld the longitudinal seam in the steel pipe cavity. By setting the support roller 13, when the steel pipe is placed on the base mechanism 1, it is convenient to rotate the steel pipe and adjust the longitudinal seam to the lowest position. In this way, there is no need to impose too many constraints when preventing, and it is convenient to adjust for easy use. In this way, when welding, it is only necessary to control the start and stop and power control of the drive motor 31 to adjust the moving speed, and the longitudinal seam of the steel pipe can be welded by the welding head 37 without manual entry, so as to minimize damage to the human body and increase welding safety.

[0024] Embodiment 2 Figure 1 - Figure 3As shown, the interior of the cross frame 11 is fixedly connected to a No. 1 reinforcing rib 12, one end of the cross frame 11 is fixedly connected to an internal block 15, and the other end of the cross frame 11 is fixedly connected to an extension block 14. The extension block 14 and the interior of the internal block 15 and both sides of the side mounting frame 41 are provided with a No. 1 connecting hole 16, and the middle of one side of the side mounting frame 41 is fixedly connected to a clamping plate 46 on both sides, and the upper and lower ends of the hydraulic cylinder 42 are fixedly connected to a mounting plate 45, and the mounting plate 45 is fixedly connected to the side mounting frame 41. The middle of the upper end of the cross frame 11 is fixedly connected to a No. 1 support frame 19 on both sides, and the two ends of the support roller 13 are fixedly connected to a connecting shaft 18. The interior of the No. 1 support frame 19 is fixedly connected to a No. 1 expansion frame 110, and the connecting shaft 18 overlaps the No. 1 support frame 19. A groove is provided on one side of another No. 2 reinforcing rib 44 for plugging with the extension block 14.

[0025] In the present invention, when installing the cross frame 11, the end of the extension block 14 needs to be inserted into the interior of another cross frame 11, and then a bolt is used to pass through the No. 1 connection hole 16 to fix the two cross frames 11, and then the clamping plate 46 is inserted into one end of the cross frame 11, and the No. 1 connection hole 16 in the other cross frame 11 is inserted into the groove inside the other side mounting frame 41, and then fixed with bolts to complete the installation. The groove formed by the internal block 15 and the cross frame 11 and the extension block 14 are matched, and preliminary positioning is performed during installation to facilitate the No. 1 connection. The connection of hole 16 facilitates the installation of bolts, making the installation more convenient. The arrangement of No. 1 reinforcing rib 12 and No. 2 reinforcing rib 44 are respectively used to ensure the strength of the cross frame 11 and the side mounting frame 41. The connection between the connecting shaft 18 and the No. 1 support frame 19 does not use a rotating connection with a bearing, but a direct overlap method is adopted to facilitate installation and subsequent replacement and maintenance. On the other hand, it will not affect the rotation use, and only needs to apply lubricating oil. The arrangement of No. 1 expansion frame 110 is used to increase the supporting strength of the connecting shaft 18.

[0026] Embodiment 3 according to Figure 1 , Figure 2 , Figure 5 and Figure 6As shown, the middle part and both sides of the middle part of the side mounting frame 41 are fixedly connected with the second reinforcing rib 44, the output end of the hydraulic cylinder 42 is fixedly connected with the plug rod 43, the plug rod 43 is plugged with the L-shaped connecting plate 25, and the other side of the upper end of the pressing plate 33 is fixedly connected with the second supporting frame 34, and the second supporting frame 34 has a first through hole 35, and a second through hole 36 is opened on one side of the middle part of one L-shaped connecting plate 25. A bottom plate 312 is arranged below the pressing plate 33, and the upper end of the bottom plate 312 is fixed between the pressing plate 33. A connecting plate 313 is fixedly connected, and limit strips 315 are fixedly connected to both sides of the middle of the upper end of the bottom plate 312, and rollers 314 are rotatably connected to both sides of the middle of the inner part of the pressure plate 33. A No. 1 slot 39 is provided at the upper end of the rack 38, and a No. 2 slot 310 is provided at the lower end of the rack 38. The lower end of the roller 314 is located in the No. 1 slot 39, and the No. 2 slot 310 is slidably connected to the limit strip 315. The No. 1 through hole 35 and the No. 2 through hole 36 are on the same side, and the No. 2 through hole 36 is located directly above the extension plate 27.

[0027] In the present invention, the plug rod 43 is provided to connect with the L-shaped connecting plate 25 by plugging, instead of directly fixing. When in use, the second expansion frame 21, the first side frame 22, and the second side frame 23 can be placed on the inner wall of the steel pipe, so as to avoid bending of the connection between the first side frame 22, the second side frame 23 and the second expansion frame 21, thereby ensuring the service life of the guide mechanism 2 and reducing damage. By adopting the meshing mode for driving, the movement accuracy is higher, and the arrangement of the No. 1 through hole 35 and the No. 2 through hole 36 is used to support the electrode and the wire of the gas shielded welding, and the electrode and the wire are supported on the surface of the extension plate 27 to avoid the phenomenon that when the steel pipe is long, the middle part of the line is pressed down due to the weight and contacts the surface of the steel pipe, causing the high temperature of welding to damage the skin of the wire, thereby ensuring the safety of use. The arrangement of the roller 314 makes the movement smoother.

[0028] Embodiment 4 according to Figure 1 , Figure 2 , Figure 5 and Figure 7As shown, the middle lower part of one side of the No. 2 expansion frame 21, the No. 1 side frame 22, and the No. 2 side frame 23 are all fixedly connected with an extension plate 27, and both sides of the upper end of the extension plate 27 are fixedly connected with end blocks 28, one side of one end block 28 is provided with a dovetail groove 210, and one side of the other end block 28 is fixedly connected with a dovetail block 29, and the interior of the end block 28 is penetrated by a through hole 26, and the lower end of the extension plate 27 is fixedly connected with a bottom support block 24, through the setting of the dovetail groove 210 and the dovetail block 29, when the No. 2 expansion frame 21, the No. 1 side frame 22, and the No. 2 side frame 23 are connected, the dovetail block 29 can be connected to the dovetail groove 210 first, and preliminary positioning can be performed, and the through hole 26 can be connected at the same time, so as to facilitate subsequent connection and installation, and through the setting of the bottom support block 24, according to the different inner diameters of the welded steel pipes, the bottom surface of the bottom support block 24 can be set with different curvatures, and the bottom surface of the bottom support block 24 can be fitted and supported with the inner wall of the steel pipe to ensure stability in use.

[0029] The method of use and working principle of the device are as follows: according to the required length of the welded steel pipe, different numbers of cross frames 11 and second extension frames 21 are selected. When installing, first assemble the cross frames 11, insert one end of the extension block 14 into the gap between the cross frame 11 and the internal block 15, and then insert the bolt into the first connection hole 16 to install the two cross frames 11. Then, insert the extension block 14 at one end of the rear end cross frame 11 into the notch of one of the side mounting frames 41, and use the bolt to tighten. The clamping plate 46 is inserted into the notch at the other end of the cross frame 11 and installed with bolts. Then, the hydraulic cylinder 42 is installed in the side mounting frame 41. Then, the bottom support block 24 is installed under the extension plate 27. The second notch 310 is connected with the limit bar 315, and the gear 311 is meshed with the rack 38. In this way, the welding mechanism 3 and the guide mechanism 2 are installed. Then, the second expansion frame 21 is installed between the first side frame 22 and the second side frame 23, and the dovetail block 29 is connected with the dovetail groove 210. The connection is fixed with bolts. After the installation is completed, the steel pipe is placed on the support roller 13, and then the steel pipe is rotated to move the longitudinal seam to the bottom, and then the guide mechanism 2 is passed through the steel pipe, and then the L-shaped connecting plate 25 is plugged with the plug rod 43, and the wire and the gas shielded welding wire are passed through the No. 2 through hole 36 and the No. 1 through hole 35, and the welding wire and the wire are connected to the welding head 37, and the wire is connected to the drive motor 31 to complete the installation, and then the hydraulic cylinder 42 is retracted until the lower end of the bottom support block 24 contacts the inner wall of the steel pipe, and the bottom support block 24 is supported by the steel pipe, and the drive motor 31 is controlled to open, and the welding head 37 is controlled to open, and the longitudinal seam of the steel pipe is welded. After the welding of one steel pipe is completed, the guide mechanism 2 is lifted up and removed, and the guide mechanism 2 is taken out of the steel pipe, and then another steel pipe is placed after the steel pipe is taken out, and the steel pipe is welded in this cycle. When welding, it is necessary to adjust the lower end of the welding head 37 to be located at the end of the longitudinal seam, and then open the welding head 37 for welding.

[0030] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An automatic gas shielded welding device for longitudinal seams in steel pipe cavities, characterized in that: It comprises a base mechanism (1), the base mechanism (1) and a side-mounting mechanism (4), a guide mechanism (2) being arranged above the base mechanism (1), and a welding mechanism (3) being installed inside the guide mechanism (2); The base mechanism (1) comprises a horizontal frame (11), a support roller (13) is arranged at the upper end of the horizontal frame (11), the horizontal frames (11) are symmetrically arranged, and a vertical frame (17) is fixedly connected between two adjacent horizontal frames (11), the side mounting mechanism (4) is arranged on both sides of the base mechanism (1), the side mounting mechanism (4) comprises a side mounting frame (41), and both sides of the middle part of the side mounting frame (41) are fixedly connected to a hydraulic cylinder (42); The guiding mechanism (2) comprises an L-shaped connecting plate (25), the number of the L-shaped connecting plates (25) being two, the welding mechanism (3) comprising a pressing plate (33), the middle of one side of the L-shaped connecting plate (25) being fixedly connected to the second side frame (23) on both sides, the middle of the other side of the L-shaped connecting plate (25) being fixedly connected to the first side frame (22) on both sides, the middle of the first side frame (22) and the second side frame (23) being arranged between the second expansion frame (21), the first side frame (22) and the second side frame (23) being fixedly connected to the second expansion frame (21), the first side frame (22) and the second side frame (23) at the lower middle part. A rack (38) is connected to the pressing plate (33); the four corners below the pressing plate (33) are rotatably connected to gears (311); a reducer (32) is fixedly connected to one side of the upper end of the pressing plate (33); a drive motor (31) is fixedly connected to the upper end of the reducer (32); an output end of the drive motor (31) is fixedly connected to an input shaft of the reducer (32); an output shaft of the reducer (32) passes through the pressing plate (33) and is fixedly connected to the shaft of one of the gears (311); the gear (311) meshes with the rack (38); and a welding head (37) is installed on one side of the pressing plate (33).

2. The automatic gas shielded welding device for longitudinal seams in steel pipe cavities according to claim 1 is characterized in that: A No. 1 reinforcing rib (12) is fixedly connected inside the cross frame (11), an internal block (15) is fixedly connected to one end of the cross frame (11), and an extension block (14) is fixedly connected to the other end of the cross frame (11), and a No. 1 connecting hole (16) is provided inside the extension block (14) and the internal block (15) as well as on both sides of the side mounting frame (41).

3. The automatic gas shielded welding device for longitudinal seams in steel pipe cavities according to claim 1 is characterized in that: A clamping plate (46) is fixedly connected to both sides of the middle of one side of the side mounting frame (41), and a mounting plate (45) is fixedly connected to the upper and lower ends of the hydraulic cylinder (42), and the mounting plate (45) is fixedly connected to the side mounting frame (41).

4. The automatic gas shielded welding device for longitudinal seams in steel pipe cavities according to claim 1 is characterized in that: A second reinforcing rib (44) is fixedly connected to the middle and both sides of the middle of the side mounting frame (41), an insertion rod (43) is fixedly connected to the output end of the hydraulic cylinder (42), the insertion rod (43) is plugged into the L-shaped connecting plate (25), and a second supporting frame (34) is fixedly connected to the other side of the upper end of the pressing plate (33), a first through hole (35) is provided inside the second supporting frame (34), and a second through hole (36) is provided on one side of the middle of one of the L-shaped connecting plates (25).

5. The automatic gas shielded welding device for longitudinal seams in steel pipe cavities according to claim 1 is characterized in that: A bottom plate (312) is provided below the pressing plate (33); a connecting plate (313) is fixedly connected between the upper end of the bottom plate (312) and the pressing plate (33); both sides of the middle of the upper end of the bottom plate (312) are fixedly connected to limiting strips (315); and both sides of the middle of the inside of the pressing plate (33) are rotatably connected to rollers (314).

6. The automatic gas shielded welding device for longitudinal seams in steel pipe cavities according to claim 5, characterized in that: The upper end of the rack (38) is provided with a first notch (39), the lower end of the rack (38) is provided with a second notch (310), the lower end of the roller (314) is located in the first notch (39), and the second notch (310) is slidably connected to the limit bar (315).

7. The automatic gas shielded welding device for longitudinal seams in steel pipe cavities according to claim 1 is characterized in that: An extension plate (27) is fixedly connected to the lower middle portion of one side of the second expansion frame (21), the first side frame (22), and the second side frame (23), and end blocks (28) are fixedly connected to both sides of the upper end of the extension plate (27).

8. The automatic gas shielded welding device for longitudinal seams in steel pipe cavities according to claim 7 is characterized in that: A dovetail groove (210) is provided on one side of one of the end blocks (28), a dovetail block (29) is fixedly connected to one side of the other end block (28), a through hole (26) is provided through the interior of the end block (28), and a bottom support block (24) is fixedly connected to the lower end of the extension plate (27).

9. The automatic gas shielded welding device for longitudinal seams in steel pipe cavities according to claim 1, characterized in that: A first support frame (19) is fixedly connected to both sides of the middle portion of the upper end of the cross frame (11), and a connecting shaft (18) is fixedly connected to both ends of the support roller (13).

10. The automatic gas shielded welding device for longitudinal seams in steel pipe cavities according to claim 9, characterized in that: The first support frame (19) is fixedly connected to the inside of the first expansion frame (110), and the connecting shaft (18) is overlapped with the first support frame (19).

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