Pipe butt welding device

Abstract

The application discloses a pipe butt welding device, which comprises a base, two positioning mechanisms, a driving mechanism and a welding mechanism. The two positioning mechanisms are respectively a first positioning mechanism and a second positioning mechanism. Each positioning mechanism comprises a mounting seat, a sleeve mounted on the mounting seat, two symmetrical elastic telescopic components arranged in the sleeve, two symmetrical arc-shaped clamping plates arranged in the sleeve and a limiting component. The elastic telescopic components and the arc-shaped clamping plates are arranged one by one in correspondence. Each elastic telescopic component comprises a plurality of elastic telescopic rod units connected between the sleeve and the arc-shaped clamping plate. The limiting component is arranged in correspondence with the elastic telescopic component, and the driving mechanism is arranged in correspondence with the limiting component, which is used for driving the limiting component to act and fix the length of the elastic telescopic rod unit after the pipe part is inserted into the arc-shaped clamping plate. The welding mechanism is mounted on the first positioning mechanism. The application can automatically align the axes of two pipe parts to be welded and automatically position and fix the pipe parts.

Description

Technical Field

[0001] This invention relates to the field of welding technology, specifically to a pipe fitting butt welding device. Background Technology

[0002] Welding is a manufacturing process and technology that joins metals or other thermoplastic materials by heating, high temperature, or high pressure. Automated welding equipment plays an increasingly important role in various industries, and its application scope is rapidly expanding. In modern industrial production, the mechanization and automation of welding processes are an inevitable trend in the modernization of the welding equipment manufacturing industry.

[0003] Existing online welding devices for processing pipe parts still have shortcomings in use. They cannot quickly align pipe parts, requiring manual positioning before welding to prevent loosening and affecting the welding effect. However, manual positioning makes the operation cumbersome, time-consuming, and labor-intensive, affecting welding efficiency. Moreover, when welding two pipe parts with different diameters, it is necessary to ensure that the center axes of the two pipe parts are strictly aligned. Manual positioning often fails to achieve precise alignment or results in poor welding quality. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a pipe fitting butt welding device that can automatically align the axes of two pipe fittings to be welded and automatically fix and position the pipe fittings.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A pipe fitting butt welding device includes a base, two positioning mechanisms, a drive mechanism, and a welding mechanism. The two positioning mechanisms are a first positioning mechanism and a second positioning mechanism, both installed on the same side of the base. Each positioning mechanism includes a mounting base, a sleeve mounted on the mounting base, two elastic telescopic components symmetrically arranged within the sleeve, two arc-shaped clamping plates symmetrically arranged within the sleeve, and a limiting component. The elastic telescopic components correspond one-to-one with the arc-shaped clamping plates, and each elastic telescopic component includes a plurality of elastic telescopic rod units connected between the sleeve and the arc-shaped clamping plates. The limiting component is configured corresponding to the elastic telescopic components, and the drive mechanism is configured corresponding to the limiting component, for driving the limiting component to fix the length of the elastic telescopic rod unit after the pipe fitting is inserted between the arc-shaped clamping plates. The welding mechanism is installed on the first positioning mechanism and located between the positioning mechanisms.

[0006] In one embodiment, each of the elastic telescopic rod units includes an outer tube connected to the inner wall of the sleeve, an inner rod with one end slidably disposed within the outer tube, and a drive rod elastic member disposed between the outer tube and the inner rod; the axis of the outer tube is perpendicular to the axis of the sleeve, the outer tube is provided with a first recessed hole corresponding to the limiting component, and the inner rod is provided with a plurality of second recessed holes that cooperate with the first recessed hole, the plurality of second recessed holes being arranged sequentially along the axial direction of the outer tube; the other end of the inner rod is connected to the arc-shaped clamping plate; the drive rod elastic member is located on the side of the inner rod close to the arc-shaped clamping plate.

[0007] In one embodiment, the limiting component includes a plurality of limiting units, the number of which is equal to the number of the elastic telescopic rod units, and they are arranged in a one-to-one correspondence. Each limiting unit includes a support seat mounted on the outer tube, a working tube mounted on the support seat, a limiting piston slidably disposed in the working tube, a first limiting elastic element disposed in the working tube, and an insertion rod connected at one end to the limiting piston. The working tube is located outside the outer tube, and the axis of the working tube is perpendicular to the axis of the outer tube. The limiting piston divides the inner cavity of the working tube into a first cavity and a second cavity. The first cavity is located on the side of the limiting piston away from the outer tube. The first limiting elastic element is located in the first cavity. The insertion rod is located on the side of the limiting piston closer to the outer tube and is disposed corresponding to the first concave hole. The driving mechanism is a pneumatic mechanism used to fill the first cavity with gas to drive the limiting piston to push the insertion rod into the first concave hole and the second concave hole.

[0008] In one embodiment, the positioning mechanism further includes ball bearing units installed within the sleeve, the number of which is equal to the number of the limiting units and is arranged in a one-to-one correspondence. Each ball bearing unit has a bead hole corresponding to its corresponding arc-shaped clamping plate. Each ball bearing unit includes a movable plate, a ball bearing matching the bead hole, and a push plate elastic member. The movable plate is located between the outer tube and the working tube, and between the arc-shaped clamping plate and the sleeve. The movable plate has a movable groove corresponding to the insertion rod for insertion. A plate slope is formed within the movable groove corresponding to the insertion rod, allowing it to abut against the insertion rod. The plate slope is located on the side of the movable groove away from the arc-shaped clamping plate and is inclined along the direction from the outer tube to the working tube towards the direction from the arc-shaped clamping plate to the outer tube. The push plate elastic member is linked to the movable plate and is used to drive the movable plate, carrying the ball bearing, into the bead hole when the force applied to the movable plate is removed from the insertion rod.

[0009] In one embodiment, the positioning mechanism further includes a positioning frame, which includes a first plate, a second plate, a third plate connecting the first plate and the second plate, and a positioning rod disposed on the second plate. The first plate is connected to the insertion rod and is located on the side of the movable plate closer to the working tube. The second plate is located on the side of the movable plate closer to the outer tube. The positioning rod is disposed on the second plate and is located on the side of the second plate facing the movable plate. The movable plate has a positioning hole corresponding to the positioning rod. When the ball is located in the ball hole, the positioning rod is inserted into the positioning hole.

[0010] In one embodiment, the limiting unit further includes a second limiting elastic element, which is disposed in the second cavity of the working tube and connected to the limiting piston and the first plate of the positioning frame; the insertion rod is slidably disposed corresponding to the second plate.

[0011] In one embodiment, the pneumatic mechanism is mounted on the base and located on the side of the base facing the positioning mechanism; the pneumatic mechanism includes a pneumatic box, an air guiding assembly, and a compressed air return assembly; the pneumatic box is mounted on the base; there are two air guiding assemblies, each corresponding to one of the positioning mechanisms, and the air guiding assembly connects the pneumatic box and the first chamber of each working tube of the corresponding positioning mechanism; the compressed air return assembly is used to drive the gas in the pneumatic box through the air guiding assembly into the first chamber of the working tube after the tubular part to be welded enters between the arc-shaped clamping plates, and to drive the gas in the first chamber of the working tube back to the pneumatic box after the tubular part is welded.

[0012] In one embodiment, the compressed air return assembly includes a compressed air unit for driving gas in the pneumatic box into a first chamber of the working tube and a return air unit for driving gas in the first chamber of the working tube back into the pneumatic box.

[0013] In one embodiment, the air compression unit includes a pneumatic piston, a push rod, and a pneumatic elastic element. The pneumatic piston is slidably disposed within the pneumatic housing. The push rod is located between the two positioning mechanisms. One end of the push rod is connected to the pneumatic piston, and the other end extends through the pneumatic housing away from the base and out of the pneumatic housing. The end of the push rod away from the pneumatic piston forms a rod slope. The rod slope is located on the side of the push rod facing the second positioning mechanism. The rod slope is inclined along the direction from the base to the push rod towards the direction from the second positioning mechanism to the first positioning mechanism. The pneumatic elastic element is located within the pneumatic housing and on the side of the pneumatic piston closer to the base.

[0014] In one embodiment, the welding mechanism includes a rotating ring rotatably sleeved on the sleeve of the first positioning mechanism, a support plate connected to the rotating ring, a connecting screw connected to the support plate, a threaded tube sleeved on the connecting screw, a connecting plate rotatably connected to the threaded tube, a rod telescopic assembly connecting the support plate and the connecting plate, and a welding torch mounted on the connecting plate. The support plate extends along the direction from the first positioning mechanism to the second positioning mechanism and is located on the side of the rotating ring facing the second positioning mechanism. The connecting screw is located on the side of the support plate facing the base. The threaded tube is threadedly engaged with the connecting screw. The connecting plate is located at the end of the connecting screw away from the support plate.

[0015] Compared with the prior art, the beneficial effects of the pipe butt welding device of the present invention are as follows: This invention, by setting up a first positioning mechanism and a second positioning mechanism, allows two tubular parts to be welded to be placed in the two positioning mechanisms respectively. Since the sleeves of the two positioning mechanisms are coaxially arranged, and the two symmetrically arranged arc-shaped clamping plates inside the sleeves are connected to the sleeves through two symmetrically arranged elastic telescopic components, the elastic forces of the two elastic telescopic components and the two arc-shaped clamping plates inside the sleeves are equal. This ensures that the central axes of the tubular parts entering the sleeves of the two positioning mechanisms are automatically aligned, guaranteeing welding quality. After the tubular parts enter the arc-shaped clamping plates, a driving mechanism drives a limiting component to fix the length of the elastic telescopic rod unit of the elastic telescopic component, thus limiting the position of the arc-shaped clamping plates. This prevents the arc-shaped clamping plates from shifting during welding of the tubular parts, ensuring a firm clamping of the tubular parts and guaranteeing welding quality. Therefore, this invention only requires inserting two tubular parts into the arc-shaped clamping plates of the two positioning mechanisms. The two symmetrically arranged elastic telescopic components of each positioning mechanism inside the sleeve can automatically drive the tubular parts to a position coaxial with the sleeve. This allows the two positioning mechanisms to automatically drive the two tubular parts to be coaxial. Moreover, after the tubular parts are inserted into the arc-shaped clamping plates of the positioning mechanisms, the driving mechanism can automatically drive the limiting component to fix the length of the elastic telescopic rod unit of the elastic telescopic component, thereby limiting the position of the arc-shaped clamping plate and realizing automatic positioning and fixing of the tubular parts. This eliminates the need for frequent operation by the operator and improves the welding efficiency and welding quality of the tubular parts. Attached Figure Description

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

[0017] Figure 1 This is a three-dimensional structural schematic diagram of a pipe fitting butt welding device according to an embodiment of the present invention; Figure 2 for Figure 1A three-dimensional structural diagram of the pipe fitting butt welding device shown after being cut open; Figure 3 for Figure 1 A three-dimensional structural diagram of the assembly consisting of the elastic telescopic rod unit, the limiting unit, the ball bearing unit, and the positioning frame. Figure 4 for Figure 3 The sectional view of the assembly shown; Figure 5 for Figure 4 Enlarged view of the area circled in the middle circle A; Figure 6 for Figure 2 Enlarged view of the area circled by circle B; Figure 7 for Figure 1 A partial structural diagram of the pneumatic mechanism in the image; Figure 8 for Figure 1 A three-dimensional structural diagram of the welding mechanism in the diagram; Figure 9 This is a cross-sectional view of the assembly consisting of a sleeve, a rotating ring, and a limiting guide rod in the pipe butt welding device according to another embodiment of the present invention.

[0018] Figure label: 11. Base; 20a. First positioning mechanism; 20b. Second positioning mechanism; 31. Mounting seat; 32. Sleeve; 321. Guide groove; 33. Arc-shaped clamping plate; 331. Bead hole; 332. Guide plate; 40. Elastic telescopic rod unit; 41. Outer tube; 411. First concave hole; 412. Slide groove; 42. Inner rod; 421. Second concave hole; 43. Drive rod elastic element; 50. Limiting unit; 51. Support seat; 52. Working tube; 521. First cavity; 522. Second cavity; 53. Limiting piston; 54. Insert rod; 55. First limiting elastic element; 56. Second limiting elastic element; 60. Ball bearing unit; 61. Moving plate; 611. Movable groove; 612. Plate inclined surface; 613. Sliding block; 62. Ball bearing. ; 63. Push plate elastic element; 70. Positioning frame; 71. First plate; 72. Second plate; 73. Third plate; 74. Positioning rod; 80. Pneumatic mechanism; 81. Pneumatic box; 811. Through hole; 82. Air guide assembly; 821. Air outlet valve; 822. Air guide pipe; 823. Air distribution pipe; 83. Compressed air unit; 831. Pneumatic piston; 832. Push rod; 8321. Rod inclined surface; 833. Pneumatic elastic element; 84. Air return unit; 841. Sealing plate; 842. Rotating shaft; 90. Welding mechanism; 91. Rotating ring; 92. Support plate; 93. Connecting screw; 94. Threaded pipe; 95. Connecting plate; 96. Welding torch; 97. Rod telescopic assembly; 971. First rod; 972. Second rod; 98. Limiting guide rod. Detailed Implementation

[0019] The following description is only a preferred embodiment of the present invention and does not limit the scope of protection of the present invention.

[0020] It should be noted that when an element is referred to as "connected to" or "disposed on" another element, it can be directly on or indirectly on that other element. In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention 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, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified. "Several" means one or more, unless otherwise explicitly specified.

[0021] Please see Figures 1 to 9 This invention provides a pipe butt welding device according to an embodiment of the present invention, comprising a base 11, two positioning mechanisms, a pneumatic mechanism 80, and a welding mechanism 90; both the positioning mechanisms and the pneumatic mechanism 80 are mounted on the base 11; both positioning mechanisms are located on the same side of the base 11; the two positioning mechanisms are a first positioning mechanism 20a and a second positioning mechanism 20b; each positioning mechanism includes a mounting base 31, a sleeve 32 mounted on the mounting base 31, two elastic telescopic components symmetrically arranged within the sleeve 32, two arc-shaped clamping plates 33 symmetrically arranged within the sleeve 32, and a limiting component; the arc-shaped clamping plate of the first positioning mechanism 20a... The diameter of the holding plate 33 is larger than the diameter of the arc-shaped clamping plate 33 of the second positioning mechanism 20b; the elastic telescopic components are arranged one-to-one with the arc-shaped clamping plates 33, and each elastic telescopic component includes several elastic telescopic rod units 40 connected between the sleeve 32 and the arc-shaped clamping plate 33; the limiting unit 50 is arranged corresponding to the elastic telescopic components; the driving mechanism is arranged corresponding to the limiting components and is used to drive the limiting components to limit the length of the elastic telescopic rod units 40; the welding mechanism 90 is installed on the sleeve 32 of the first positioning mechanism 20a and is located between the two positioning mechanisms, and is used to weld the tubular parts that have been positioned and fixed by the two positioning mechanisms.

[0022] Specifically, by setting a first positioning mechanism 20a and a second positioning mechanism 20b on the base 11, the two tubular parts to be welded can be restricted and positioned respectively. It should be noted that the sleeves 32 of the two positioning mechanisms are coaxially arranged, and each sleeve 32 is connected to two symmetrically arranged arc-shaped clamping plates 33 through two symmetrically arranged elastic telescopic components, so that the arc-shaped clamping plates 33 of the two positioning mechanisms can also be coaxially arranged. When the two tubular parts to be welded are placed between the arc-shaped clamping plates 33 in the two sleeves 32 respectively, the elastic telescopic rod unit 40 automatically deforms under force. During the process of placing the tubular parts to be welded between the two arc-shaped clamping plates 33 of the positioning mechanism, the thicker tubular part is first placed between the arc-shaped clamping plates 33 of the first positioning mechanism 20a, and then another tubular part is placed between the arc-shaped clamping plates 33 of the second positioning mechanism 20b. The elastic force exerted by the two symmetrically arranged elastic telescopic components inside the sleeve 32 on the two arc-shaped clamping plates 33 is equal, so that the tubular parts in each sleeve 32 can be placed in the center position, and the central axes of the tubular parts clamped by the arc-shaped clamping plates 33 in the two sleeves 32 can be in the same straight line, which is fast and accurate. When the tubular parts move in the second positioning mechanism 20b, the pneumatic mechanism 80 drives the limiting component to limit the length of the deformed elastic telescopic component, thereby ensuring the positioning effect of the positioning mechanism on the tubular parts to be welded, so that the arc-shaped clamping plates 33 will not squeeze the elastic telescopic rod unit 40 and shift during the welding of the tubular parts; then the welding mechanism 90 is controlled to perform welding work on the joint of the two tubular parts. This invention enables automatic and rapid positioning of tubular parts, eliminating the need for tedious operations by workers. It not only ensures the welding quality of the parts but also improves the welding efficiency of tubular parts.

[0023] like Figure 2 As shown, the arc-shaped clamping plate 33 of the first positioning mechanism 20a, which is away from the second positioning mechanism 20b, and the arc-shaped clamping plate 33 of the second positioning mechanism 20b, which is away from the first positioning mechanism 20a, both have a conical guide plate 332. The diameter of the guide plate 332 gradually increases in the direction away from the arc-shaped clamping plate 33.

[0024] Specifically, by setting a tapered guide plate 332 at the end of the arc-shaped clamping plate 33, the tubular parts to be welded can be quickly inserted between the arc-shaped clamping plates 33 under the guidance of the guide plate 332. The operation is simple and quick, which can improve the positioning and installation efficiency of the parts.

[0025] In this embodiment, the elastic telescopic rod units 40 are preferably evenly distributed between the arc-shaped clamping plate 33 and the sleeve 32. For example... Figures 3 to 5As shown, each elastic telescopic rod unit 40 includes an outer tube 41 connected to the inner wall of the sleeve 32, an inner rod 42 with one end slidably disposed within the outer tube 41, and a drive rod elastic element 43 disposed between the outer tube 41 and the inner rod 42; the axis of the outer tube 41 is perpendicular to the axis of the sleeve 32, and the outer tube 41 is provided with a first recessed hole 411 corresponding to the limiting component; the inner rod 42 is provided with a plurality of second recessed holes 421 that cooperate with the first recessed hole 411, and the plurality of second recessed holes 421 are arranged sequentially along the axial direction of the outer tube 41; the other end of the inner rod 42 is connected to an arc-shaped clamping plate 33; the drive rod elastic element 43 is located on the side of the inner rod 42 near the arc-shaped clamping plate 33. In this embodiment, the drive rod elastic element 43 is preferably a spring.

[0026] When the tubular part to be welded is inserted between the two arc-shaped clamping plates 33, the arc-shaped clamping plates 33 are driven by force to compress the inner rod 42 and move the drive rod elastic element 43 toward the inner wall of the sleeve 32, thereby compressing the elastic telescopic rod unit 40. When the two arc-shaped clamping plates 33 in the sleeve 32 have clamped the tubular part, the pneumatic mechanism 80 drives the limiting component to insert into the overlapping first concave hole 411 and second concave hole 421, fixing the length of the elastic telescopic rod unit 40. This prevents the elastic telescopic rod unit 40 from freely expanding and contracting during the welding of the tubular part, ensuring the clamping stability of the arc-shaped clamping plates 33 on the tubular part, and thus ensuring the welding quality of the tubular part. In this embodiment, the drive rod elastic element 43 is preferably a spring.

[0027] The limiting assembly includes several limiting units 50, with an equal number of limiting units 50 and elastic telescopic rod units 40, and each unit is arranged in a corresponding manner. Each limiting unit 50 includes a support base 51 mounted on the outer tube 41, a working tube 52 mounted on the support base 51, a limiting piston 53 slidingly disposed within the working tube 52, a first limiting elastic element 55 disposed within the working tube 52, and an insertion rod 54 with one end connected to the limiting piston 53. The working tube 52 is located outside the outer tube 41, and the axis of the working tube 52 is perpendicular to the axis of the outer tube 41. The piston 53 divides the inner cavity of the working tube 52 into a first cavity 521 and a second cavity 522. The first cavity 521 is located on the side of the piston 53 away from the outer tube 41. The first limiting elastic element 55 is located inside the first cavity 521. The insertion rod 54 is located on the side of the piston 53 near the outer tube 41 and is positioned corresponding to the first recess 411. The driving mechanism is a pneumatic mechanism 80, which is used to fill the first cavity 521 with gas, thereby driving the piston 53 to push the insertion rod 54 into the first recess 411 and the second recess 421. In this embodiment, the first limiting elastic element 55 is preferably a spring.

[0028] Specifically, when the limiting component is working, the pneumatic mechanism 80 first fills the first cavity 521 of the working tube 52 with air. The filled air drives the limiting piston 53 to move towards the first concave hole 411 with the insertion rod 54 until the insertion rod 54 is inserted into the overlapping first concave hole 411 and second concave hole 421. When the two tubular parts are welded and the welded tubular parts need to be removed from the positioning mechanism, the pneumatic mechanism 80 removes the air from the first cavity 521, reducing the air pressure in the first cavity 521. Under the elastic restoring force of the first limiting elastic element 55, the limiting piston 53 returns to its original position with the insertion rod 54, so that the insertion rod 54 moves out of the first concave hole 411 and second concave hole 421. This releases the length fixation of the elastic telescopic component by the limiting component and reduces the fixing force of the arc-shaped clamping plate 33 on the tubular parts. Subsequently, the welded tubular parts can be removed from between the arc-shaped clamping plates 33 of the positioning mechanism with less effort.

[0029] The positioning mechanism also includes ball bearing units 60 installed in the sleeve 32. The number of ball bearing units is equal to the number of limiting units 50, and they are arranged in a one-to-one correspondence. Each ball bearing unit is provided with a ball hole 331 on the arc-shaped clamping plate 33. The ball bearing unit 60 includes a movable plate 61, a ball bearing 62 that matches the ball hole 331, and a push plate elastic element 63. The movable plate 61 is located between the outer tube 41 and the working tube 52, and between the arc-shaped clamping plate 33 and the sleeve 32. The movable plate 61 is provided with a movable groove 611 corresponding to the insertion rod 54 for the insertion rod 54 to be inserted. The movable groove 611 is formed with a plate slope 61 that can abut against the insertion rod 54. 2. The inclined plate 612 is located on the side of the movable groove 611 away from the arc-shaped clamping plate 33, and is inclined along the direction from the outer tube 41 to the working tube 52 towards the direction from the arc-shaped clamping plate 33 to the outer tube 41, so that when the insertion rod 54 enters into the movable groove 611 and abuts against the inclined plate 612, it can push the moving plate 61 with the ball 62 to move away from the arc-shaped clamping plate 33, so that the ball 62 moves out of the ball hole 331; the push plate elastic element 63 is linked to the sliding block 613, which is used to drive the moving plate 61 with the ball 62 to re-insert into the ball hole 331 when the insertion rod 54 removes the pushing force applied to the moving plate 61.

[0030] When tubular parts need to be clamped, the ball bearing 62 is located in the bead hole 331 of the arc-shaped clamping plate 33 and protrudes from the inner surface of the arc-shaped clamping plate 33. When the tubular part is inserted between the two arc-shaped clamping plates 33, the tubular part contacts the ball bearing 62 and drives the ball bearing 62 to roll. Under the action of the rolling ball bearing 62, the wear degree of the tubular part when placed between the two arc-shaped clamping plates 33 can be reduced. After the tubular part is placed between the arc-shaped clamping plates 33, when the limiting component needs to be activated, the movement of the insert rod 54 will first enter the movable groove 611 of the movable plate 61 and abut against the inclined plate 612 in the movable groove 611. The insert rod 54 pushes the movable plate 61 through the inclined plate 612 to overcome the elastic force of the push plate elastic element 63 and move away from the arc-shaped clamping plate 33, driving the ball bearing 62 to move out of the bead hole 331, so that the ball bearing 62 no longer contacts the tubular part between the arc-shaped clamping plates 33. When the moving plate 61 drives the sliding block 613 to overcome the elastic force of the push plate elastic element 63, it slides in the groove 412. Under the guidance of the sliding block 613 and the groove 412, the moving plate 61 can make stable linear movement. As the ball 62 moves out of the ball hole 331 with the moving plate 61, the elastic telescopic rod unit 40 pushes the arc-shaped clamping plate 33 to move towards the pipe part, so that the arc-shaped clamping plate 33 replaces the ball 62 to contact the pipe part, improves the stability of the pipe part positioning, and thus ensures the welding quality. When the tubular parts are welded and need to be removed from the positioning mechanism, the pneumatic mechanism 80 drives the limiting unit 50 to move, so that the insertion rod 54 of the limiting unit 50 moves out of the second concave hole 421, the first concave hole 411 and the movable groove 611 in sequence, which makes it easy to remove the welded tubular parts from the positioning mechanism. During the process of the insertion rod 54 moving out of the movable groove 611, the elastic restoring force of the push plate elastic element 63 drives the moving plate 61 to re-enter the ball hole 331 with the ball 62, so as to facilitate the next tubular part to be welded to enter between the two arc-shaped clamping plates 33 of the positioning mechanism.

[0031] Furthermore, the outer tube 41 has a groove 412 on the side facing the moving plate 61, and a sliding block 613 is provided on the moving plate 61 corresponding to the groove 412, the sliding block 613 being slidably disposed within the groove 412; the push plate elastic member 63 is disposed within the groove 412 and is linked to the sliding block 613. In this embodiment, the push plate elastic member 63 is preferably a spring, and is disposed on the side of the sliding block 613 away from the arc-shaped clamping plate 33.

[0032] During the movement of the movable plate 61, the movable plate 61 simultaneously drives the sliding block 613 to slide within the slide groove 412. Under the guidance of the sliding block 613 and the slide groove 412, the movable plate 61 can move in a stable linear motion.

[0033] Preferably, the end of the insertion rod 54 furthest from the limiting piston 53 is hemispherical. This arrangement allows the insertion rod 54 to be smoothly inserted into the first recess 411 and the second recess 421, and also ensures that the contact between the insertion rod 54 and the inclined plate 612 is a point contact, which can reduce the wear between the insertion rod 54 and the inclined plate 612.

[0034] The positioning mechanism also includes a positioning frame 70, which includes a first plate 71, a second plate 72, a third plate 73 connecting the first plate 71 and the second plate 72, and a positioning rod disposed on the second plate 72. The first plate 71 is connected to the insertion rod 54 and is located on the side of the moving plate 61 near the working tube 52. The second plate 72 is located on the side of the moving plate 61 near the outer tube 41. The positioning rod 74 is disposed on the second plate 72 and is located on the side of the second plate 72 facing the moving plate 61. The moving plate 61 has a positioning hole corresponding to the positioning rod 74. When the ball 62 is located in the ball hole 331, the positioning rod 74 is inserted into the positioning hole.

[0035] Specifically, by setting positioning holes on the movable plate 61 and setting positioning rods 74 on the positioning frame 70 corresponding to the positioning holes, the position of the movable plate 61 can be fixed, preventing the ball bearings 62 from being stressed when they contact the tubular parts on the arc-shaped clamping plate 33, thus avoiding movement of the movable plate 61 and affecting the stability of the contact between the ball bearings 62 and the tubular parts. When the insertion rod 54 moves down, the insertion rod 54 drives the positioning frame 70 to move down, causing the positioning rod 74 on the positioning frame 70 to run out of the positioning hole, no longer restricting the positioning hole, allowing the movable plate 61 to move freely.

[0036] Furthermore, the limiting unit 50 also includes a second limiting elastic element 56, which is disposed in the second cavity 522 of the working tube 52 and connects the limiting piston 53 and the first plate 71 of the positioning frame 70; the insertion rod 54 is slidably disposed corresponding to the second plate 72. As the insertion rod 54 continues to move downward, the positioning frame 70 abuts against the elastic telescopic rod unit 40, the second limiting elastic element 56 is compressed, and the insertion rod 54 continues to move downward, limiting the length of the elastic telescopic rod unit 40. By setting the insertion rod 54 to slide relative to the second rod 972, and setting the second limiting elastic element 56 to connect the piston and the second rod 972, the distance between the working tube 52 and the inner rod 42 can be reduced, achieving the beneficial effect of further reducing the size of the entire positioning mechanism. Moreover, when the distance between the working tube 52 and the inner rod 42 is reduced to a certain extent, the second plate 72 of the positioning frame 70 will abut against the inner rod 42 as the insertion rod 54 moves down. Since the insertion rod 54 is movable relative to the second plate 72, the positioning frame 70 will not hinder the insertion rod 54 from continuing to move toward the first concave hole 411 after it abuts against the inner rod 42. After the second plate 72 of the positioning frame 70 abuts against the inner rod 42, the insertion rod 54 can continue to move down relative to the second plate 72 of the positioning frame 70 and enter the first concave hole 411 and the second concave hole 421, thereby fixing the length of the elastic telescopic rod unit 40.

[0037] like Figure 1 As shown, the pneumatic mechanism 80 is mounted on the base 11, and preferably located on the side of the base 11 facing the positioning mechanism. The pneumatic mechanism 80 includes a pneumatic box 81 fixed on the base 11, an air guide assembly 82, and a compressed air return assembly. There are two air guide assemblies 82, and each air guide assembly 82 is arranged in a corresponding manner to a positioning mechanism. The air guide assembly 82 connects the pneumatic box 81 and the first cavity 521 of each working tube 52 of the corresponding positioning mechanism, so that the two air guide assemblies 82 can respectively deliver gas to the limiting components of the two positioning mechanisms to drive the limiting components to move and limit the length of the elastic telescopic rod unit 40. The compressed air return assembly is used to drive the gas in the pneumatic box 81 to enter the first cavity 521 of the working tube 52 of the limiting component through the air guide assembly 82 after the entire tubular part to be welded has entered between the arc-shaped clamping plates 33, and to drive the gas in the first cavity 521 of the working tube 52 of the limiting component to return to the pneumatic box 81 after the tubular part is welded.

[0038] Specifically, when the tubular parts to be welded are placed between the arc-shaped clamping plates 33 and the pneumatic mechanism 80 needs to work, the compressed air return assembly drives the air in the pneumatic box 81 to enter the first cavity 521 of the working tube 52 of the limiting unit 50 through the air guide assembly 82. This gas generates a pushing force on the limiting piston 53, causing the limiting piston 53 to move and insert the insertion rod 54 into the first concave hole 411 of the outer tube 41 and the second concave hole 421 of the inner rod 42, so as to limit and fix the outer tube 41 and the inner rod 42, and fix the length of the elastic telescopic rod unit 40. After the two tubular parts are welded, the gas in the first chamber 521 of the working tube 52 is returned to the pneumatic box 81 through the air guide assembly 82 by the compressed air return assembly, which reduces the air pressure in the first chamber 521 of the working tube 52. As the air pressure in the first chamber 521 decreases, the limiting piston 53 moves the insertion rod 54 away from the outer tube 41 under the elastic restoring force of the first limiting elastic element 55, so that the insertion rod 54 runs out from the first concave hole 411 and the second concave hole 421, releasing the length limit on the elastic telescopic rod unit 40, and thus releasing the position limit on the arc-shaped clamping plate 33, so that the welded tubular parts can be taken out of the positioning mechanism with less effort.

[0039] like Figure 6As shown, each air guiding component 82 includes an air outlet valve 821 disposed on the pneumatic housing 81, an air guiding pipe 822 connected to the air outlet valve 821, and several air distribution pipes 823 connected to the air guiding pipes 822. The number of air distribution pipes 823 of each air guiding component 82 is equal to the number of working pipes 52 of the corresponding positioning mechanism, and they are arranged one-to-one. The air distribution pipes 823 are connected to the first chamber 521 of the working pipe 52. When it is necessary to supply gas to the limiting component, the gas in the pneumatic housing 81 enters the air guiding pipe 822 through the air outlet valve 821. The air guiding pipe 822 is interconnected with the multiple air distribution pipes 823. Each air distribution pipe 823 is interconnected with the working pipe 52 of the limiting component, so that the gas in the pneumatic housing 81 enters the first chamber 521 of the working pipe 52 of the limiting component in sequence through the air outlet valve 821, the air guiding pipe 822, and the air distribution pipes 823.

[0040] In this embodiment, as Figure 7 As shown, the compressed air return assembly includes a compressed air unit 83 for driving gas in the pneumatic housing 81 into the first chamber 521 of the working pipe 52, and a return air unit 84 for driving gas in the first chamber 521 of the working pipe 52 back into the pneumatic housing 81. In other embodiments, the compressed air return unit 84 can also be an air pump, which is installed on the air guide pipe 822. The air pump can drive the gas in the pneumatic housing 81 to flow through the air guide assembly 82 into the first chamber 521 of the working pipe 52, thereby driving the limiting assembly to fix the length of the elastic telescopic rod unit 40. After the tubular parts are welded, the power generated by the air pump can drive the gas in the first chamber 521 of the working pipe 52 back into the pneumatic housing 81, thereby driving the limiting assembly to release the fixation of the length of the elastic telescopic rod unit 40.

[0041] For further details, please refer to the following: Figure 6 The compressed air unit 83 includes a pneumatic piston 831, a push rod 832, and a pneumatic elastic element 833. The pneumatic piston 831 is slidably disposed inside the pneumatic housing 81. The push rod 832 is located between two positioning mechanisms. One end of the push rod 832 is connected to the pneumatic piston 831, and the other end extends out of the pneumatic housing 81 away from the base 11. A rod inclined surface 8321 is formed at the end of the push rod 832 away from the pneumatic piston 831. The rod inclined surface 8321 is located on the side of the push rod 832 facing the second positioning mechanism 20b. The rod inclined surface 8321 is inclined along the direction from the base 11 to the push rod 832 towards the direction from the second positioning mechanism 20b to the first positioning mechanism 20a. The pneumatic elastic element 833 is located inside the pneumatic housing 81 and on the side of the pneumatic piston 831 closest to the base 11. In this embodiment, the pneumatic elastic element is preferably a spring.

[0042] Specifically, the two tubular parts to be welded are placed between the arc-shaped clamping plates 33 of each positioning mechanism. First, the thicker tubular part is placed between the arc-shaped clamping plates 33 of the first positioning mechanism 20a. Then, the thinner tubular part is placed between the arc-shaped clamping plates 33 of the second positioning mechanism 20b. When the insertion end of the thinner tubular part moves out of the clamping range of the arc-shaped clamping plates 33 of the second positioning mechanism 20b and into the space between the first positioning mechanism 20a and the second positioning mechanism 20b, the thinner tubular part abuts against the inclined surface of the push rod 832. On 8321, the push rod 832 is pushed by the inclined surface of the rod 8321 to compress the pneumatic elastic element 833, which in turn drives the pneumatic piston 831 to slide in the pneumatic box 81 towards the base 11. The sliding pneumatic piston 831 inputs the air in the pneumatic box 81 into the first cavity 521 of the working tube 52 of the limiting component through the air guide assembly 82, which drives the limiting piston 53 to insert the insertion rod 54 into the first concave hole 411 and the second concave hole 421, so that the pneumatic mechanism 80 drives the limiting component to move. The operation is simple and convenient, which can reduce the workload of the workers and improve the welding efficiency.

[0043] like Figure 7 As shown, the pneumatic box 81 has a through hole 811. The air return unit 84 includes a sealing plate 841, a rotating shaft 842, and a torsion spring. The sealing plate 841 is provided with the through hole 811 and is rotatably connected to the pneumatic box 81 via the rotating shaft 842 to seal the through hole 811. The torsion spring is provided on the rotating shaft 842 to drive the sealing plate 841 to automatically reset and seal the through hole 811. A sealing gasket is provided on the side of the sealing plate 841 facing the pneumatic box 81.

[0044] Specifically, by providing a through hole 811 on the outside of the pneumatic box 81 and sealing the through hole 811 with a sealing plate 841, and then providing a sealing gasket on the sealing plate 841, it can be ensured that when the limiting piston 53 compresses the air in the pneumatic box 81, the air in the pneumatic box 81 can only be discharged through the air outlet valve 821, and cannot be discharged through the through hole 811. When it is necessary to release the driving force of the pneumatic mechanism 80 on the limiting component, by moving the sealing plate 841, the sealing plate 841 rotates away from the through hole 811 around the pin, the sealing plate 841 no longer blocks the through hole 811, the pneumatic box 81 is no longer sealed, and the air in the pneumatic box 81 is released. As the body pressure decreases, the air in the working tube 52 returns to the pneumatic box 81 through the air guide assembly 82, thereby reducing the gas pressure in the first chamber 521 of the working tube 52. As the gas pressure in the first chamber 521 of the working tube 52 gradually decreases, the limiting piston 53 in the working tube 52 resets under the elastic restoring force of the pneumatic elastic element 833, causing the insertion rod 54 of the limiting unit 50 to move out from the first concave hole 411 and the second concave hole 421, releasing the length restriction on the elastic telescopic rod unit 40, allowing the arc-shaped clamping plate holding the tubular parts to loosen, making it easier to remove the welded tubular parts from the positioning mechanism with less effort.

[0045] In this embodiment, as Figure 8 As shown, the welding mechanism 90 includes a rotating ring 91 rotatably sleeved on the sleeve 32 of the first positioning mechanism 20a, a support plate 92 connecting the rotating ring 91, a connecting screw 93 connecting the support plate 92, a threaded tube 94 sleeved on the connecting screw 93, a connecting plate 95 rotatably connected to the threaded tube 94, a rod telescopic assembly 97 connecting the support plate 92 and the connecting plate 95, and a welding torch 96 mounted on the connecting plate 95. The support plate 92 extends along the direction from the first positioning mechanism 20a to the second positioning mechanism 20b and is located on the side of the rotating ring 91 facing the second positioning mechanism 20b. The connecting screw 93 is located on the side of the support plate 92 facing the base 11. The threaded tube 94 is threadedly engaged with the connecting screw 93. The connecting plate 95 is located at the end of the connecting screw 93 away from the support plate 92.

[0046] Specifically, when welding two tubular parts after docking, based on the distance between the tubular parts and the welding torch 96, the threaded tube 94 is rotated, causing it to move relative to the connecting screw 93, bringing the welding torch 96 closer to the joint of the two tubular parts. Then, by rotating the rotating ring 91, the welding torch 96 is driven to perform circumferential welding around the joint of the two tubular parts. The operation is simple and convenient. When the threaded tube moves relative to the connecting screw 93, the rod telescopic assembly 97 extends and retracts, preventing the connecting plate 95 from causing the welding torch 96 to rotate, and ensuring stable linear motion during welding.

[0047] Furthermore, the telescopic rod assembly 97 includes a first rod 971 connected at one end to a support plate 92 and a second rod 972 connected at one end to a connecting plate 95. Both the first rod 971 and the second rod 972 are hollow. The end of the first rod 971 away from the support plate 92 can be slidably inserted into the second rod 972, or the end of the second rod 972 away from the connecting plate 95 can be slidably inserted into the first rod 971. The telescopic movement of the telescopic rod assembly 97 is achieved by the movement of the first rod 971 relative to the second rod 972.

[0048] In other feasible embodiments, such as Figure 9As shown, the outer wall of the sleeve 32 of the first positioning mechanism 20a is provided with an annular guide groove 321 coaxial with the sleeve 32, corresponding to the rotating ring 91. The rotating ring 91 is provided with a threaded hole 911. The welding mechanism 90 also includes a limiting guide rod 98. One end of the limiting guide rod 98 is located on the side of the rotating ring 91 facing away from the sleeve 32, and the other end passes through the threaded hole 911 and is inserted into the annular guide groove 321. The limiting guide rod 98 is provided with an external thread that mates with the threaded hole 911. The cooperation between the limiting guide rod 98 and the guide groove 321 ensures that the rotating ring 91 will not shift along the axial direction of the sleeve 32 when it rotates on the sleeve 32, thereby preventing the welding end of the welding torch 96 from deviating from the joint of the two tubular parts along the axial direction of the sleeve 32, thus ensuring the welding quality.

[0049] The specific working principle of the pipe fitting butt welding device in this embodiment is as follows: In use, two tubular parts to be welded are placed between the arc-shaped clamping plates 33 of the two positioning mechanisms. First, the thicker tubular part is guided into the arc-shaped clamping plates 33 of the first positioning mechanism 20a through the guide plate 332. Then, the other tubular part is guided into the arc-shaped clamping plates 33 of the second positioning mechanism 20b through the guide plate 332. During the placement of the tubular parts in the positioning mechanisms, the parts come into contact with and abut against the guide plate 332, and the guide plate 332 is driven by force to move the arc-shaped clamping plates on both sides. When the holding plate 33 separates, the elastic telescopic rod unit 40 automatically deforms under force, facilitating the quick insertion of tubular parts between the two arc-shaped clamping plates 33 of the positioning mechanism. This simple and quick operation improves the efficiency of part positioning and installation. At this time, the ball bearings 62 are located within the ball holes 331. After the tubular part enters between the two arc-shaped clamping plates 33 of the positioning mechanism, the tubular part contacts the ball bearings 62 protruding from the inner surface of the arc-shaped clamping plates 33, driving the ball bearings 62 to roll. The rolling ball bearings 62 reduce the wear on the tubular part when placed between the arc-shaped clamping plates 33. The sleeves 32 of the two positioning mechanisms are coaxially arranged, and the elastic telescopic components arranged symmetrically exert equal elastic forces on the two symmetrically arranged arc-shaped clamping plates 33. This ensures that each tubular part entering between the arc-shaped clamping plates 33 is placed in the center, thus ensuring that the central axes of the tubular parts in the two positioning mechanisms are aligned, quickly and accurately. During the movement of the tubular parts within the second positioning mechanism 20b, when the entry end of the thinner tubular part moves out of the clamping range of the arc-shaped clamping plate 33 and enters between the two positioning mechanisms, the thinner tubular part abuts against the push... The inclined plate 612 of the rod 832 pushes the push rod 832 to drive the pneumatic piston 831 to slide in the pneumatic box 81. The pneumatic piston 831 moves down and discharges the air in the pneumatic box 81 into the air guide pipe 822 through the air outlet valve 821. The air guide pipe 822 then inputs the gas into each branch pipe 823. Each branch pipe 823 then discharges the gas into the first chamber 521 of the working pipe 52 of the corresponding limiting unit 50. After the gas enters the first chamber 521, it drives the limiting piston 53 to move towards the elastic telescopic rod unit 40 with the insertion rod 54.During this process, the insertion rod 54 drives the positioning frame 70 to move downwards, causing the positioning rod 74 on the positioning frame 70 to move out of the positioning hole in the moving plate 61, no longer restricting the moving plate 61, allowing the moving plate 61 to move freely. The insertion rod 54 first inserts into the movable groove 611 and abuts against the inclined surface 612 of the plate, and pushes the moving plate 61 away from the arc-shaped clamping plate 33 through the inclined surface 612. The moving plate 61 drives the sliding block 613 to overcome the elasticity of the push plate elastic element 63 in the sliding groove 412. As the force moves, the ball 62 moves out of the ball hole 331 along with the moving plate 61. During the movement of the ball 62, the elastic telescopic rod unit 40 pushes the arc-shaped clamping plate 33 towards the tubular part, so that the arc-shaped clamping plate 33 replaces the ball 62 to contact the tubular part, improving the stability of the positioning mechanism in positioning the tubular part and ensuring the welding quality. Furthermore, as the insertion rod 54 continues to move downward, the second plate 72 of the positioning frame 70 abuts against the inner rod 42 of the elastic telescopic rod unit 40, and the second limiting elastic element 5... 6 is compressed, and the insertion rod 54 continues to move downward relative to the second plate 72 of the positioning frame 70 and is inserted into the first concave hole 411 and the second concave hole 421. The length of the elastic telescopic rod unit 40 is fixed to prevent the elastic telescopic rod unit 40 from freely expanding and contracting during the welding of the parts, which would affect the clamping stability of the arc-shaped clamping plate 33 on the parts and lead to poor welding quality. At this time, the tubular parts placed in the two positioning mechanisms are connected. Then, according to the distance between the tubular parts and the welding gun 96, the threaded tube 94 is rotated, so that the threaded tube 94 moves relative to the connecting screw 93. The threaded tube 94 drives the welding end of the welding gun 96 on the connecting plate 95 to move to the joint of the two tubular parts, so that the welding gun 96 can perform welding work on the joint of the tubular parts. After adjusting the distance between the welding gun 96 and the joint of the tubular parts, the rotating ring 91 is rotated, so that the rotating ring 91 drives the welding gun 96 to rotate around the joint of the two tubular parts, so that the joint of the two tubular parts can be welded.

[0050] The above description is only a preferred embodiment of the present invention. For those skilled in the art, there will be changes in the specific implementation and application scope based on the ideas of the present invention. The content of this specification should not be construed as a limitation of the present invention.

Claims

1. A pipe fitting butt welding device, characterized in that, The device includes a base, two positioning mechanisms, a drive mechanism, and a welding mechanism. The two positioning mechanisms are a first positioning mechanism and a second positioning mechanism, both mounted on the same side of the base. Each positioning mechanism includes a mounting base, a sleeve mounted on the mounting base, two elastic telescopic components symmetrically arranged within the sleeve, two arc-shaped clamping plates symmetrically arranged within the sleeve, and a limiting component. Each elastic telescopic component corresponds to one of the arc-shaped clamping plates, and each elastic telescopic component includes several elastic telescopic rod units connected between the sleeve and the arc-shaped clamping plates. The limiting component corresponds to each elastic telescopic component, and the drive mechanism corresponds to each limiting component, used to drive the limiting component to fix the length of the elastic telescopic rod units after the tubular part is inserted between the arc-shaped clamping plates. The welding mechanism is mounted on the first positioning mechanism and located between the positioning mechanisms. Each of the elastic telescopic rod units includes an outer tube connected to the inner wall of the sleeve, an inner rod with one end slidably disposed within the outer tube, and a drive rod elastic element disposed between the outer tube and the inner rod; the axis of the outer tube is perpendicular to the axis of the sleeve, the outer tube is provided with a first recessed hole corresponding to the limiting component, and the inner rod is provided with a plurality of second recessed holes that cooperate with the first recessed hole, the plurality of second recessed holes being arranged sequentially along the axial direction of the outer tube; the other end of the inner rod is connected to the arc-shaped clamping plate; the drive rod elastic element is located on the side of the inner rod closer to the arc-shaped clamping plate; The limiting component includes a plurality of limiting units, the number of the limiting units and the elastic telescopic rod units are equal and are set in a one-to-one correspondence. The limiting unit includes a plug rod, which is used to insert into the corresponding first concave hole and second concave hole after the pipe is inserted between the two arc-shaped clamping plates of the positioning mechanism. The limiting unit includes a support seat mounted on the outer tube, a working tube mounted on the support seat, a limiting piston slidably disposed within the working tube, a first limiting elastic element disposed within the working tube, and an insertion rod connected at one end to the limiting piston; the working tube is located outside the outer tube, and the axis of the working tube is perpendicular to the axis of the outer tube; the limiting piston divides the inner cavity of the working tube into a first cavity and a second cavity, the first cavity being located on the side of the limiting piston away from the outer tube; the first limiting elastic element is located within the first cavity; the insertion rod is located on the side of the limiting piston closer to the outer tube and is disposed corresponding to the first concave hole; the driving mechanism is a pneumatic mechanism, used to fill the first cavity with gas to drive the limiting piston to push the insertion rod into the first concave hole and the second concave hole; The positioning mechanism further includes ball bearing units installed within the sleeve. The number of ball bearing units is equal to the number of limiting units, and they are arranged in a one-to-one correspondence. Each ball bearing unit is provided with a bead hole on the arc-shaped clamping plate. Each ball bearing unit includes a movable plate, a ball bearing that matches the bead hole, and a push plate elastic element. The movable plate is located between the outer tube and the working tube, and between the arc-shaped clamping plate and the sleeve. The movable plate has a movable groove for inserting the insertion rod corresponding to the insertion rod. The movable groove has a plate slope that can abut against the insertion rod. The plate slope is located on the side of the movable groove away from the arc-shaped clamping plate, and is inclined from the direction from the outer tube to the working tube towards the direction from the arc-shaped clamping plate to the outer tube. The push plate elastic element is linked to the movable plate and is used to drive the movable plate to insert the ball bearing into the bead hole when the force applied to the movable plate is removed from the insertion rod. When tubular parts need to be clamped, the ball is located in the bead hole of the arc-shaped clamping plate and protrudes from the inner surface of the arc-shaped clamping plate. When the tubular part is inserted between the two arc-shaped clamping plates, the tubular part contacts the ball and drives the ball to roll. Under the action of the rolling ball, the wear degree of the tubular part when placed between the two arc-shaped clamping plates can be reduced.

2. The pipe fitting butt welding device according to claim 1, characterized in that, The positioning mechanism further includes a positioning frame, which includes a first plate, a second plate, a third plate connecting the first plate and the second plate, and a positioning rod disposed on the second plate. The first plate is connected to the insertion rod and is located on the side of the moving plate closer to the working tube. The second plate is located on the side of the moving plate closer to the outer tube. The positioning rod is disposed on the second plate and is located on the side of the second plate facing the moving plate. The moving plate has a positioning hole corresponding to the positioning rod. When the ball is located in the ball hole, the positioning rod is inserted into the positioning hole.

3. The pipe fitting butt welding device according to claim 2, characterized in that, The limiting unit further includes a second limiting elastic element, which is disposed in the second cavity of the working tube and connected to the limiting piston and the first plate of the positioning frame; the insertion rod is slidably disposed corresponding to the second plate.

4. The pipe fitting butt welding device according to claim 1, characterized in that, The pneumatic mechanism is mounted on the base and located on the side of the base facing the positioning mechanism. The pneumatic mechanism includes a pneumatic box, an air guiding assembly, and a compressed air return assembly. The pneumatic box is mounted on the base. There are two air guiding assemblies, each corresponding to one of the positioning mechanisms. The air guiding assembly connects the pneumatic box to the first cavity of each working tube of the corresponding positioning mechanism. The compressed air return assembly is used to drive the gas in the pneumatic box through the air guiding assembly into the first cavity of the working tube after the tubular part to be welded enters between the arc-shaped clamping plates, and to drive the gas in the first cavity of the working tube back to the pneumatic box after the tubular part is welded.

5. The pipe fitting butt welding device according to claim 4, characterized in that, The compressed air return assembly includes a compressed air unit for driving the gas in the pneumatic box into the first cavity of the working pipe and a return air unit for driving the gas in the first cavity of the working pipe back into the pneumatic box.

6. The pipe fitting butt welding device according to claim 5, characterized in that, The compressed air unit includes a pneumatic piston, a push rod, and a pneumatic elastic element. The pneumatic piston is slidably disposed inside the pneumatic housing. The push rod is located between the two positioning mechanisms. One end of the push rod is connected to the pneumatic piston, and the other end extends through the pneumatic housing away from the base and out of the pneumatic housing. The end of the push rod away from the pneumatic piston forms a rod slope. The rod slope is located on the side of the push rod facing the second positioning mechanism. The rod slope is inclined along the direction from the base to the push rod towards the direction from the second positioning mechanism to the first positioning mechanism. The pneumatic elastic element is located inside the pneumatic housing and on the side of the pneumatic piston closer to the base.

7. The pipe fitting butt welding device according to claim 1, characterized in that, The welding mechanism includes a rotating ring rotatably sleeved on the sleeve of the first positioning mechanism, a support plate connected to the rotating ring, a connecting screw connected to the support plate, a threaded tube sleeved on the connecting screw, a connecting plate rotatably connected to the threaded tube, a rod telescopic assembly connecting the support plate and the connecting plate, and a welding torch mounted on the connecting plate. The support plate extends along the direction from the first positioning mechanism to the second positioning mechanism and is located on the side of the rotating ring facing the second positioning mechanism. The connecting screw is located on the side of the support plate facing the base. The threaded tube is threadedly engaged with the connecting screw. The connecting plate is located at the end of the connecting screw away from the support plate.

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