A method of welding large spliced pipe sections

Abstract

The present application relates to a kind of welding methods of large-scale spliced pipe fittings, belong to welding technical field, it includes the following steps: step one: from the adaptive coaxial inner clamping between connecting device and pipe inner wall;Step two: from the welding mechanism of connecting device and installation component cooperation drive is close to the place to be welded;Step three: welding mechanism drives electrode free end and the start point of place to be welded alignment;Step four: welding unit carries out welding using electrode;Step five: welding mechanism moves to avoid the moving track of replacement mechanism;Step six: replacement mechanism pulls electrode and moves towards welding mechanism;Step seven: welding mechanism moves to make clamping area a and clamping area b be located on the same straight line, replacement mechanism drives electrode tail end to be located in clamping area a, clamping area a closes and clamps electrode, clamping area b opens and cancels the clamping of electrode, then, welding mechanism moves to avoid the moving track of replacement mechanism, replacement mechanism resets.

Description

Technical Field

[0001] This invention relates to the field of welding, and more specifically to a welding method for large spliced ​​pipe fittings. Background Technology

[0002] Large circular pipe fittings are widely used as pipes and outer shells in water supply, drainage, heating, gas supply, long-distance transportation of oil and natural gas, agricultural irrigation, hydraulic engineering, and various industrial installations. When welding large pipe fittings, small lifting devices are needed to lift them so that the ends of the two pipe fittings are aligned before welding. In existing technologies, manual labor is generally used to weld the outer and inner sides of the pipe fitting joint. However, large pipe fittings are usually placed on-site, assembled, and then welded. Given the wide range of applications and complex surrounding environments, the circular shape of the pipe fitting makes standing difficult, and the dim lighting inside the pipe, welders often have to tilt their heads back while welding towards the highest point of the joint. The slag and dust generated during welding further increase the difficulty and can easily fall into the eyes, harming the welder's health. Therefore, manual welding of the inner wall of the pipe fitting joint is quite challenging. Based on this, this invention proposes a welding method for large assembled pipe fittings. Summary of the Invention

[0003] To address the problems mentioned in the background above, the present invention provides a welding method for large spliced ​​pipe fittings.

[0004] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows.

[0005] A welding method for large spliced ​​pipe fittings includes a self-connecting device and a welding device. The self-connecting device adapts to the pipe diameter and clamps the welding equipment inside the pipe fitting. It also allows the welding equipment to move axially along and rotate around the pipe fitting. The welding device includes a mounting frame connected to the self-connecting device. A welding mechanism and a replacement mechanism are mounted on the mounting frame. The welding mechanism performs welding on the area to be welded on the pipe fitting. The replacement mechanism replaces the welding rods used in the welding mechanism. The method includes the following steps:

[0006] Step 1: Pull the welding equipment to move it into the pipe fitting, and form an adaptive coaxial internal clamp between the self-connecting device and the inner wall of the pipe fitting;

[0007] Step 2: The self-connecting device pulls the welding equipment along the axial direction of the pipe fitting toward the welding point. At the same time, the installation components used to connect the self-connecting device and the welding device drive the welding mechanism closer to the welding point.

[0008] Step 3: The welding mechanism drives the free end of the welding electrode to complete the positioning and alignment with the starting point of the area to be welded;

[0009] Step 4: The welding unit in the welding mechanism begins to weld using welding rods, and the welding action simulates the fish scale welding action;

[0010] Step 5: The welding mechanism moves to avoid the movement trajectory of the replacement mechanism;

[0011] Step Six: Move the welding electrode towards the welding mechanism using the replacement mechanism;

[0012] Step 7: The welding mechanism moves so that the clamping area a of the welding mechanism holding the welding rod and the clamping area b of the changing mechanism holding the welding rod are on the same straight line. The changing mechanism drives the welding rod to move towards the clamping area a. When the tail end of the welding rod is in the clamping area a, the clamping area a closes to clamp the welding rod, and the clamping area b opens to release the welding rod clamping. Then, the welding mechanism moves to avoid the movement trajectory of the changing mechanism, the changing mechanism resets, and the welding actions in steps 3 and 4 above are repeated.

[0013] Further, in step six above: Motor 12 drives synchronous belt group b forward one notch, positioning the welding rod within clamping area b. One notch refers to the distance between two adjacent sets of sleeves. Then, Motor 13 drives cam 2 to rotate. Since the spring force coefficient of the coil spring is greater than that of spring a, which is greater than that of the elastic plate, initially, cam 2 pushes the inner rod to move, pushing the connecting block through the inclined plane, causing the two sets of connecting blocks to move away from each other. This, in turn, causes the clamping sections of the two sets of clamping plates to move closer together, closing clamping area b and clamping the welding rod. The elastic plate is compressed, and at this time, the inner rod contacts the closed end of the outer sleeve column. Next, cam 2 pushes the inner... When the inner rod contacts the closed end of the outer sleeve, the inner rod, outer sleeve, and clamping area b move together, overcoming the magnetic attraction of the magnet to the welding rod and pulling the welding rod out of the sleeve. Spring a is compressed. After the welding rod is pulled out of the sleeve, the end point of cam two contacts the inner rod. At this time, the limiting protrusion restricts the rotation of cam two, and the rotating frame, limiting protrusion, and cam two are locked together. Next, motor thirteen drives the rotating frame to rotate through cam two and limiting protrusion. The coil spring is compressed, and the parts set on the rotating frame rotate with the rotating frame until the center line of clamping area b is parallel to the center line of clamping area a, at which point motor thirteen stops running.

[0014] Furthermore, in step seven above: the motor five drives the synchronous belt group a to move, moving the fixed frame one and the welding unit as a whole until the center line of the clamping area b and the center line of the clamping area a are on the same straight line. At this time, the motor five stops running, and the insertion rod is inserted into the insertion hole, and the rotating frame is restricted from rotating.

[0015] Motor 13 drives cam 2 to rotate in the opposite direction. Because the rotating frame is restricted from rotating, spring a initially releases its elastic force, driving the outer sleeve, inner rod, and clamping area b to move in the opposite direction together, pulling the tail end of the welding rod into clamping area a. Then, motor 13 stops running while motor 11 runs, causing clamping area a to close and clamp the welding rod. Then, motor 11 stops running while motor 13 continues running. At this time, the elastic plate releases its elastic force, causing clamping area b to open and release the clamping of the welding rod. Then, motor 5 runs, driving synchronous belt group a to run, moving the fixed frame 1 and the welding unit as a whole to avoid the movement trajectory of the changing mechanism. During this process, the insertion rod leaves the insertion hole. Then, the coil spring releases its elastic force, causing the rotating frame to rotate in the opposite direction and reset.

[0016] Compared with the prior art, the beneficial effects of this invention are as follows:

[0017] In this solution, automatic welding of the inner side of the pipe fitting can be achieved. The entire welding process consists of four actions: adaptive internal clamping, moving closer to the part to be welded, welding unit performing welding action, and welding rod replacement, thus realizing automatic welding of the part of the pipe fitting to be welded.

[0018] In the welding unit, the welding action involves welding with a welding rod by energizing the welding clamp, the traveling unit driving the entire welding equipment to rotate around the core axis of the pipe, the six-motor drive moving the welding rod, and the ten-motor drive causing the welding rod to sway. These four actions work together to simulate the fish-scale welding action, welding the parts of the pipe to be welded. This results in higher welding quality, and the amplitude of the welding rod sway in the fish-scale welding action can be adjusted to match the actual situation of the pipe, improving the adaptability of the welding.

[0019] In the electrode replacement process, the same power source, namely motor 13, drives the electrode to perform the following actions: clamping the electrode in clamping area b, pulling the electrode out of the sleeve, aligning the electrode with clamping area a of the welding unit, feeding the electrode into clamping area a, removing clamping from clamping area b, and resetting. In other words, the six sub-actions that make up the electrode replacement process are all driven by the same power source, motor 13. These six actions are combined into a continuous action to achieve electrode replacement. There is no time wastage or error accumulation between the actions, resulting in higher replacement efficiency.

[0020] Those skilled in the art would readily conceive of using a series of drive structures to achieve electrode replacement. It would be easy to imagine using six separate drive structures to perform the six sub-actions. However, this approach is flawed. Firstly, the sub-actions are disjointed and cumbersome, lacking seamless transitions between them. The accumulated time wasted in these transitions is considerable, impacting welding efficiency. Secondly, each sub-action has its own driving force, and over time, the accumulated errors in each sub-action lead to decreased accuracy, causing electrode replacement errors. Furthermore, the overall structure is bulky and unfavorable for automated welding. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the present invention when it is located inside a pipe fitting;

[0022] Figure 2 This is a schematic diagram of the structure of the present invention;

[0023] Figure 3 This is a schematic diagram of the self-connecting device;

[0024] Figure 4 This is a schematic diagram showing the connection between the suspension frame, the main frame, and the wheel frame.

[0025] Figure 5 This is an exploded view of the suspension frame, main frame, and motor.

[0026] Figure 6 This is a structural diagram of the wheel frame and the traveling unit;

[0027] Figure 7 This is a structural diagram of the mounting components;

[0028] Figure 8 This is a schematic diagram of the welding device in its initial state.

[0029] Figure 9 A schematic diagram of the welding device when the welding electrode is clamped in clamping area b and clamping areas a and b are on the same straight line;

[0030] Figure 10 A schematic diagram of the welding device when the welding electrode is held in clamping zone a;

[0031] Figure 11 This is a structural diagram of the mounting frame, synchronous belt group a, and synchronous belt group b.

[0032] Figure 12 This is a schematic diagram of the sleeve, magnet, and welding rod;

[0033] Figure 13 This is a schematic diagram of the welding mechanism;

[0034] Figure 14 A schematic diagram of a partial structure of the welding mechanism. Figure 1 ;

[0035] Figure 15 A schematic diagram of a partial structure of the welding mechanism. Figure 2 ;

[0036] Figure 16 This is a schematic diagram of the welding unit structure;

[0037] Figure 17 A structural diagram of the replacement mechanism;

[0038] Figure 18 This is a structural diagram of the inner rod, rotating frame, coil spring, and cam.

[0039] Figure 19 This is a schematic diagram of the outer column, inner rod, movable seat, fixed rod, and spring a;

[0040] Figure 20 This is a schematic diagram of the outer column, inner rod, connecting block, elastic plate, and clamping plate.

[0041] The labels in the attached diagram are:

[0042] 100. Self-connecting device; 101. Main frame; 102. Suspension frame; 103. Wheel frame; 104. Connecting rod a; 105. Connecting rod b; 106. Guide rod; 107. Motor 1; 108. Bogie; 109. Roller; 110. Motor 2; 111. Motor 3; 112. Motor 4; 113. Connecting rod c; 114. Connecting frame;

[0043] 200. Welding equipment; 300. Mounting frame;

[0044] 400. Welding mechanism; 401. Synchronous belt group a; 402. Motor five; 403. Fixed frame one; 404. Slide block; 405. Slide rod; 406. Fixed frame two; 407. Threaded rod; 408. Motor six; 409. Motor seven; 410. Movable frame one; 411. Motor eight; 412. Movable frame two; 413. Insert rod; 414. Fixed frame three; 415. Movable frame three; 416. Welding frame; 417. Swing frame; 418. Linking component one; 419. Motor nine; 420. Bracket; 421. Motor ten; 422. Motor eleven; 423. Slider; 424. Welding clamp; 425. Linking component two;

[0045] 500. Replacement mechanism; 501. Synchronous belt group b; 502. Motor 12; 503. Sleeve; 504. Magnet; 505. Support frame; 506. Rotating frame; 507. Coil spring; 508. Motor 13; 509. Cam 2; 510. Limiting protrusion; 511. Inner rod; 512. Outer column; 513. Movable seat; 514. Fixed rod; 515. Spring a; 516. Connecting block; 517. Elastic sheet; 518. Clamping plate; 519. Spring b. Detailed Implementation

[0046] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0047] This solution is for welding large pipe fittings, which are round in shape.

[0048] like Figures 1-20 As shown, a large-scale pipe fitting welding equipment includes a self-connecting device 100 and a welding device 200. The self-connecting device 100 is suspended on the cantilever of a crane, and the welding equipment is sent into the pipe fitting through the cantilever of the crane. Of course, other methods of sending the welding equipment into the pipe fitting are also possible. The self-connecting device 100 adapts to the pipe diameter and clamps the welding equipment inside the pipe fitting. It can also pull the welding equipment to move along the pipe fitting axis and rotate around the pipe fitting axis.

[0049] like Figures 3-7 As shown, the self-connecting device 100 includes a main frame 101 and a suspension frame 102. One end of the suspension frame 102 is connected to the cantilever of the crane, and the other end extends to a guide rod 106. The main frame 101 is slidably mounted on the guide rod 106. A motor 107 is mounted on the main frame 101. The motor 107 is a linear screw stepper motor, whose output shaft is parallel to the guide rod 106 and whose output end is connected to the suspension frame 102. The output end of the linear screw stepper motor performs linear motion, which is achievable with existing technology. The operation of the motor 107 can increase or decrease the distance between the main frame 101 and the suspension frame 102.

[0050] The self-connecting device 100 also includes a wheel frame 103, which is connected to the main frame 101 by a connector. When the distance between the main frame 101 and the suspension frame 102 changes, the wheel frame 103 is pulled closer to or away from the axis of the main frame 101 by the connector. The main frame 101 is a cylindrical frame shape.

[0051] Specifically, such as Figure 4 As shown, the connector includes a connecting rod a104 hinged between the main frame 101 and the wheel frame 103, and the hinge axis formed at the hinge is perpendicular to the axis of the main frame 101. Two sets of connecting rods a104 are arranged along the axial direction of the main frame 101, and the two sets of connecting rods a104 are parallel to each other.

[0052] A connecting rod b105 is hinged between the suspension frame 102 and the connecting rod a104, and the hinge axis formed at the hinge point is perpendicular to the axis of the main frame 101.

[0053] When the distance between the suspension frame 102 and the main frame 101 increases, the wheel frame 103 is pulled closer to the main frame 101 by the cooperation of the connecting rod b105 and the connecting rod a104. When the distance between the suspension frame 102 and the main frame 101 decreases, the wheel frame 103 is pushed away from the main frame 101 by the cooperation of the connecting rod b105 and the connecting rod a104.

[0054] like Figure 3As shown, multiple sets of wheel frames 103 are arranged in an array along the circumference of the main frame 101. The attached diagram of this scheme shows three sets, and each set of wheel frames 103 is equipped with a traveling unit.

[0055] Specifically, such as Figure 6 As shown, the travel unit includes a bogie 108 rotatably mounted on a wheel frame 103, and the axial direction of the rotation of the bogie 108 is distributed radially along the main frame 101. A second motor 110 is mounted on the wheel frame 103, and the output end of the second motor 110 is poweredly connected to the input end of the bogie 108. The operation of the second motor 110 drives the bogie 108 to rotate.

[0056] Two sets of side plates are mounted on the side of the bogie 108 away from the main frame 101. A roller 109 is rotatably mounted between the two sets of side plates, with the axis of the roller 109 perpendicular to the axis of rotation of the bogie 108. The roller 109 is hollow and equipped with a driving component for rotating it. The driving component includes a motor frame positioned between the two sets of side plates, and a motor 111 is mounted on the motor frame. The output end of the motor 111 is poweredly connected to the roller 109, driving the roller 109 to rotate. Preferably, as shown... Figure 6 As shown, the power transmission route between motor 3111 and roller 109 consists of a worm gear and a gear ring.

[0057] The process by which the self-connecting device 100 clamps the pipe fitting inside the welding equipment:

[0058] First, the welding equipment is moved into the pipe fitting using existing technologies such as the crane's cantilever. Then, motor 107 is started, reducing the distance between the main frame 101 and the suspension frame 102. Through the cooperation of connecting rod b105 and connecting rod a104, the wheel frame 103 is pushed away from the main frame 101 until the rollers 109 on the wheel frame 103 are in contact with the inner wall of the pipe fitting. At this point, the welding equipment is clamped and installed inside the pipe fitting with the main frame 101 and the pipe fitting arranged coaxially, with the cooperation of three sets of traveling units. Then, the suspension between the crane's cantilever and the welding equipment is removed.

[0059] Motor 2 110 drives the roller 109 to rotate parallel to the pipe fitting's axis. Then, motor 3 111 drives the roller 109 to rotate, thus pulling the welding equipment to rotate around the pipe fitting's axis within the pipe fitting. Motor 2 110 drives the roller 109 to rotate perpendicular to the pipe fitting's axis, and motor 3 111 drives the roller 109 to rotate, thus pulling the welding equipment to move along the pipe fitting's axis within the pipe fitting.

[0060] In addition, in order to ensure the smooth and orderly progress of the entire process, two sets of connecting rods a104 are located on the same side of the wheel frame 103 to form a connecting rod group. The connecting rod group is provided with two sets located on both sides of the wheel frame 103. Each set of traveling units on the wheel frame 103 is provided with two sets located at both ends of the wheel frame 103.

[0061] like Figure 3 and Figure 7 As shown, the main frame 101 is also provided with an installation component on the side opposite to the suspension frame 102, for installing the welding device 200.

[0062] Specifically, the installation components include a connecting frame 114, and a connecting rod c113 is hinged between the connecting frame 114 and the main frame 101. The hinge axis formed at the hinge is perpendicular to the axis of the main frame 101. There are two sets of connecting rods c113, and the two sets are parallel to each other.

[0063] A motor 112 is mounted on the main frame 101. A hinge shaft formed at the hinge point of the connecting rod c113 and the main frame 101 is powered by the motor 112. The motor 112 drives the hinge shaft to rotate, which in turn drives the connecting frame 114 to move via the connecting rod c113. The welding device 200 is connected to the connecting frame 114. The movement of the connecting frame 114 moves the welding device 200 along with it. This ensures that the welding device 200 can move closer to or further away from the inner wall of the pipe fitting. Preferably, as shown... Figure 7 As shown, the power connection route between the hinge shaft formed at the hinge point of the connecting rod c113 and the main frame 101 and the motor 112 is composed of a bevel gear set and a worm gear.

[0064] like Figures 8-10 As shown, the welding device 200 includes a mounting frame 300 connected to the connecting frame 114. The mounting frame 300 is equipped with a welding mechanism 400 and a replacement mechanism 500. The welding mechanism 400 is used to perform welding on the part of the pipe fitting to be welded, and the replacement mechanism 500 is used to replace the welding rod of the welding mechanism 400.

[0065] like Figure 11 As shown, the welding mechanism 400 includes a synchronous belt assembly a401 and a motor 402 mounted on the mounting frame 300. The conveying direction of the synchronous belt assembly a401 is parallel to the axial direction of the main frame 101. The input end of the synchronous belt assembly a401 is poweredly connected to the motor 402. The synchronous belt assembly a401 is driven to run by the motor 402. The synchronous belt assembly a401 is composed of a synchronous belt and a synchronous pulley, which is a technology that can be realized. The synchronous belt in the synchronous belt assembly a401 is connected to a fixed frame 403. The movement of the synchronous belt assembly a401 moves the fixed frame 403 together with it.

[0066] like Figure 13As shown, a slide block 404 is installed on a fixed frame 403, and a slide rod 405 is slidably installed on the slide block 404. The extension direction of the slide rod 405 is perpendicular to the axial direction of the main frame 101. A fixed frame 406 is provided at the end of the slide rod 405. A threaded rod 407 is rotatably installed on the fixed frame 406. The threaded rod 407 is parallel to the slide rod 405 and is threadedly connected to the slide block 404. A motor 408 is also installed on the fixed frame 406. The motor 408 is poweredly connected to the threaded rod 407. The motor 408 drives the threaded rod 407 to rotate. The threaded rod 407 rotates and moves along the axial direction at the same time. The movement of the threaded rod 407 moves the fixed frame 406 together with it.

[0067] like Figure 13 and Figure 14 As shown, a movable frame 410 is rotatably mounted on a fixed frame 406. The axis of rotation of the movable frame 410 is parallel to the extension direction of the slide rod 405. The input end of the movable frame 410 is powered by a motor 409 mounted on the fixed frame 406. The motor 409 drives the movable frame 410 to rotate. A movable frame 412 is rotatably mounted on the movable frame 410. The axis of rotation of the movable frame 412 is perpendicular to the axis of rotation of the movable frame 410. The input end of the movable frame 412 is powered by a motor 411 mounted on the movable frame 410. The motor 411 drives the movable frame 412 to rotate. Preferably, the motor 409 and the movable frame 410 are connected by a coupling, and the motor 411 and the movable frame 412 are connected by a worm gear.

[0068] like Figures 14-16 As shown, the movable frame 2 412 is equipped with a welding unit, which is used to hold welding rods and perform welding on the parts of the pipe fitting to be welded.

[0069] Specifically, the welding unit includes a fixed frame 3 414 mounted on the movable frame 2 412, a movable frame 3 415 rotatably mounted on the fixed frame 3 414, the axis of rotation of the movable frame 3 415 being parallel to the axis of rotation of the movable frame 1 410, and a welding frame 416 rotatably mounted on the movable frame 3 415, the axis of rotation of the welding frame 416 being parallel to the axis of rotation of the movable frame 2 412.

[0070] A slider 423 is slidably installed inside the welding frame 416, and the sliding direction is perpendicular to the axis of rotation of the movable frame 415. Two sets of sliders 423 are arranged in a direction perpendicular to their own sliding direction. One end of the slider 423 extends to a welding clamp 424. Two sets of welding clamps 424 are arranged accordingly. The area between the two sets of welding clamps 424 is the clamping area a for holding the welding rod.

[0071] A motor 11 422 is installed on the welding frame 416. The output end of the motor 11 422 is equipped with a lead screw 1. A lead screw seat is installed on the external thread of the lead screw 1. The lead screw seat and the welding frame 416 form a sliding fit with the lead screw 1 in a guiding direction parallel to the axis of the lead screw 1. The axis of the lead screw 1 is parallel to the sliding direction of the slider 423. The motor 11 422 drives the lead screw seat to move along the axis of the lead screw 1.

[0072] A second linkage 425 is provided between the lead screw seat and the slider 423. When the lead screw seat moves, the second linkage 425 drives the two sets of sliders 423 to move closer or further apart, thereby causing the clamping area a to close or open. Preferably, the second linkage 425 includes a linkage hole 1 provided on the slider 423 and a protrusion 1 provided on the lead screw seat. The linkage hole 1 is arranged at an inclination and the free end of the protrusion 1 slides within the linkage hole 1. When the lead screw seat moves, the two sets of sliders 423 are driven to move closer together through the cooperation of the linkage hole 1 and the protrusion 1. Conversely, when the lead screw seat moves in the opposite direction, the two sets of sliders 423 move further apart.

[0073] like Figure 14 and Figure 15 As shown, a drive unit is installed on the movable frame 412. The drive unit is used to drive the welding frame 416 to swing, simulating the fish scale welding action in manual welding, so as to make the welding result better and the welding quality better.

[0074] Specifically, the drive unit includes a lead screw 2 and a guide rod mounted on the movable frame 2 412. The axes of both are parallel to the rotation axis of the movable frame 3 415. The input end of the lead screw 2 is powered by a motor 9 419, and a bracket 420 is threaded on its external side. The bracket 420 also forms a sliding fit with the guide rod. When the motor 9 419 drives the lead screw 2 to rotate, the bracket 420 moves along the axis of the guide rod.

[0075] A motor 421 is mounted on the bracket 420. The axis of the motor 421 is perpendicular to the axis of the lead screw 2. A swing frame 417 is provided on the welding frame 416. A linkage 418 is provided between the motor 421 and the swing frame 417. The linkage 418 is used to pull the swing frame 417 to swing, thereby pulling the welding frame 416 to swing, in conjunction with the welding to perform fish scale welding. Preferably, the linkage 418 includes a linkage rod. One end of the linkage rod is hinged to the movable frame 412 and the hinge axis formed is parallel to the axis of the motor 421. The other end is ball-hinged to the swing frame 417. The linkage rod is also provided with a linkage hole 2. The guiding direction of the linkage hole 2 is parallel to the extension direction of the linkage rod. A cam 1 is provided at the output end of the motor 421. A pin 2 is provided on the cam 1. The free end of the pin 2 slides in the linkage hole 2.

[0076] Motor 421 operates by cooperating with cam 1, pin 2, and connecting hole 2 to drive the connecting rod to deflect around the hinge axis. During the deflection of the connecting rod, the swing frame 417, which is ball-jointed with it, swings together with the welding frame 416, simulating the swaying motion in fish-scale welding, thus improving the welding quality. In addition, motor 419 can drive the support 420 to move, thereby adjusting the initial position of pin 2 in connecting hole 2, and then adjusting the swing amplitude of swing frame 417 and welding frame 416, thus adjusting the amplitude of the swaying motion in fish-scale welding to match the actual situation of the pipe fitting, thereby improving the adaptability of welding.

[0077] Welding process of welding mechanism 400:

[0078] After the self-connecting device 100 achieves internal clamping between itself and the inner wall of the pipe, the traveling unit drives the welding equipment to move to the vicinity of the position to be welded, and then the motor 412 drives the welding device 200, that is, drives the welding mechanism 400 to approach the inner wall of the pipe.

[0079] Then, motor 6 408 drives fixed frame 2 406 to move axially along threaded rod 407. The movement of fixed frame 2 406 moves the welding unit along with it. At the same time, motor 7 409 drives movable frame 1 410 to rotate. The rotation of movable frame 1 410 moves the welding unit along with it. At the same time, motor 8 411 drives movable frame 2 412 to rotate. The rotation of movable frame 2 412 moves the welding unit along with it. At the same time, motor 5 402 drives fixed frame 1 403 to move axially along the pipe fitting. The movement of fixed frame 1 403 moves the welding unit along with it. Based on this, through the cooperation of motor 5 402, motor 6 408, motor 7 409 and motor 8 411, the welding unit is driven to move in the three-dimensional coordinate system. Specifically, the free end of the welding rod held by the welding unit is driven to move in the three-dimensional coordinate system, so that the free end of the welding rod is positioned and aligned with the starting point of the place to be welded.

[0080] Then, the welding unit begins welding using welding rods. The welding technique using welding rods is achievable with existing technology and will not be elaborated here. At the same time, the traveling unit drives the entire welding equipment to rotate around the axis of the main frame 101, that is, around the axis of the pipe fitting. Simultaneously, motor 408 drives the welding unit, that is, drives the free end of the welding rod to move closer to the inner wall of the pipe fitting along the axial direction of the threaded rod 407, thereby driving the welding rod to feed. At the same time, motor 421 drives the welding unit to oscillate. The welding of the welding rod, the feeding movement of the welding rod, and the oscillation of the welding rod work together to simulate the fish scale welding action and weld the part of the pipe fitting to be welded.

[0081] The above welding process is for welding the joint of two pipe fittings after they are coaxially spliced ​​together. The joint to be welded is a circular shape. In addition, the cooperation of motors 6 (408), 7 (409), and 8 (411) can drive the free end of the welding rod to move in the three-dimensional coordinate system. Since the traveling unit can not only drive the welding equipment to rotate around the pipe fitting axis, but also drive the welding equipment to move along the pipe fitting axis, and since the deflection amplitude of the welding rod is adjustable, through the cooperation of the above three, the welding equipment can also weld other shapes of joints to be welded on the inner wall of the pipe fitting. These will not be described in detail here.

[0082] like Figures 8-11 As shown, the replacement mechanism 500 includes a storage unit disposed on the mounting frame 300 for storing welding electrodes, specifically, as... Figure 11 and Figure 12 As shown, the storage unit includes a synchronous belt assembly b501 and a motor 12 502 mounted on the mounting frame 300. The conveying direction of the synchronous belt assembly b501 is parallel to the axial direction of the main frame 101. Its input end is poweredly connected to the motor 12 502, which drives the synchronous belt assembly b501 to run. The synchronous belt assembly b501 is composed of a synchronous belt and a synchronous pulley, which is a technology that can be realized in the prior art. The outer surface of the synchronous belt of the synchronous belt assembly b501 is provided with vertically arranged sleeves 503. A magnet 504 is provided at the lower opening of the sleeve 503. The welding rod is inserted into the sleeve 503 and attracted by the magnet 504, thereby storing the welding rod in the storage unit. Multiple sets of sleeves 503 are arranged in an array along the extension direction of the synchronous belt assembly b501.

[0083] like Figures 8-10 As shown, the replacement mechanism 500 also includes a replacement unit, which is used to replace the welding rods of the welding unit. The replacement unit is located near the synchronous belt group b501. The synchronous belt group b501 and its corresponding part do not store welding rods. This is a structural layout design and is not the core, so it will not be described in detail.

[0084] Specifically, such as Figures 17-20 As shown, the replacement unit includes a support frame 505 mounted on the mounting frame 300. The support frame 505 and the welding unit are located on the same side of the mounting frame 300. A rotating frame 506 is rotatably mounted on the support frame 505, and the axis of rotation of the rotating frame 506 is parallel to the axis of the main frame 101. A coil spring 507 is provided at the connection between the rotating frame 506 and the support frame 505.

[0085] A fixing rod 514 is provided on the rotating frame 506, such as Figure 8As shown, in the initial state, the extension direction of the fixed rod 514 is parallel to the axial direction of the threaded rod 407. A nut is provided at the free end of the fixed rod 514. A movable seat 513 is slidably installed on the outside of the fixed rod 514. A spring a515 is sleeved on the outside of the fixed rod 514 between the nut and the movable seat 513.

[0086] An outer sleeve column 512 is provided on the movable seat 513. The outer sleeve column 512 is parallel to the fixed rod 514. One end of the outer sleeve column 512 is open and connected to the movable seat 513, and the other end is closed. An inner rod 511 is slidably installed inside the outer sleeve column 512. One end of the inner rod 511 extends into the rotating frame 506, and the other end is close to the closed end of the outer sleeve column 512. This end is provided with two sets of inclined surfaces. The distance between the two sets of inclined surfaces decreases along the extension direction of the outer sleeve column 512 from the open end to the closed end. Two sets of connecting blocks 516 are also provided inside the outer sleeve column 512. The two sets of connecting blocks 516 are located on opposite sides of the two sets of inclined surfaces. The connecting blocks 516 and the outer sleeve column 512 form a sliding fit with the guiding direction perpendicular to the conveying direction of the synchronous belt group b501. An elastic sheet 517 is also provided between the connecting blocks 516 and the outer sleeve column 512. Two sets of elastic sheets 517 are provided and are located on opposite sides of the two sets of connecting blocks 516.

[0087] The replacement unit also includes a clamping plate 518, which consists of a clamping section and a connecting section. The clamping section extends parallel to the conveying direction of the synchronous belt set b501. The connecting section is used for the connection between the clamping section and the connecting block 516. Two sets of clamping plates 518 are provided corresponding to the connecting blocks 516. The free ends of the clamping sections of the two sets of clamping plates 518 constitute the clamping area b. Figure 8 As shown, in the initial state, the center line of the clamping area b coincides with the axis of any sleeve 503. When the motor 12 502 drives the synchronous belt group b501 forward one unit, the welding rod can be located in the clamping area b. One unit refers to the distance between two adjacent sets of sleeves 503.

[0088] A motor 13 508 is mounted on the support frame 505. The rotation axis of the motor 13 508 and the rotating frame 506 are arranged coaxially. The output end of the motor 13 508 extends into the rotating frame 506 and is provided with a cam 2 509. The cam 2 509 contacts the inner rod 511. The point of the cam 2 509 closest to the motor 13 508 is the starting point, and the point of the farthest point is the ending point. In the initial state, the starting point of the cam 2 509 contacts the inner rod 511. A limiting protrusion 510 is provided on the rotating frame 506. The limiting protrusion 510 is used to limit the rotation of the cam 2 509 after the ending point of the cam 2 509 contacts the inner rod 511.

[0089] like Figure 9 , Figure 10 and Figure 14As shown, a plug rod 413 extends from the movable frame 412, and a corresponding socket is provided on the rotating frame 506. When the clamping area a and the clamping area b are on the same straight line, the plug rod 413 is inserted into the socket.

[0090] The process of changing welding rods for welding units using the replacement mechanism 500:

[0091] First, the operation of motor 5402 drives the synchronous belt group a401 to move, which moves the fixed frame 1403 and the welding unit as a whole, leaving enough space for the replacement mechanism 500.

[0092] Then, motor 12 502 drives synchronous belt group b501 forward one step, so that the welding rod is located in the clamping area b. One step refers to the distance between two adjacent sets of sleeves 503.

[0093] Then, motor 13 508 drives cam 2 509 to rotate. Since the elastic coefficient of coil spring 507 is greater than that of spring a 515, which is greater than that of elastic plate 517, cam 2 509 initially moves by pushing against inner rod 511. Through the inclined surface, it pushes against connecting block 516, causing the two sets of connecting blocks 516 to move away from each other. This, in turn, causes the clamping sections of the two sets of clamping plates 518 to move closer to each other, clamping area b closes, clamping the welding rod. Elastic plate 517 is compressed, and at this time, inner rod 511 contacts the closed end of outer column 512. Next, when cam 2 509 pushes against inner rod 511, because inner rod 511 contacts the closed end of outer column 512, inner rod 511, outer column 512, and clamping area b move together. The electrode is moved to overcome the magnetic attraction of magnet 504 to the welding rod, pulling the welding rod out of sleeve 503. Spring a515 is compressed. After the welding rod is pulled out of sleeve 503, the end point of cam two 509 contacts inner rod 511. At this time, limiting protrusion 510 restricts the rotation of cam two 509. The rotating frame 506, limiting protrusion 510, and cam two 509 are locked together and can be regarded as one unit. Next, motor thirteen 508 drives the rotating frame 506 to rotate through cam two 509 and limiting protrusion 510. The coil spring 507 is compressed, and the parts set on the rotating frame 506 rotate with the rotating frame 506 until the center line of clamping area b is parallel to the center line of clamping area a. Then motor thirteen 508 stops running. Figure 9 What is shown

[0094] Then, motor 5 402 drives synchronous belt group a 401 to move, carrying fixed frame 1 403 and welding unit as a whole to move until the center line of clamping area b and the center line of clamping area a are on the same straight line. At this time, motor 5 402 stops running. At this time, the insertion rod 413 is inserted into the insertion hole, and the rotating frame 506 is restricted from rotating.

[0095] Then, motor 13 508 drives cam 2 509 to rotate in the opposite direction. Because the rotating frame 506 is restricted from rotation, spring a 515 initially releases its elastic force, driving the outer sleeve column 512, inner rod 511, and clamping area b to move in the opposite direction together, pulling the tail end of the welding rod into clamping area a. Then, motor 13 508 stops running while motor 11 422 runs, causing clamping area a to close and clamp the welding rod. Then, motor 11 422 stops running while motor 13 508 continues running. At this time, elastic plate 517 releases its elastic force, causing clamping area b to open and releasing the clamping of the welding rod. Figure 10 What is shown;

[0096] Then, motor 5402 drives synchronous belt group a401 to move, moving the fixed frame 1403 and welding unit as a whole, leaving enough space for the replacement mechanism 500. During this process, the insertion rod 413 leaves the insertion hole, and then the coil spring 507 releases its elasticity to make the rotating frame 506 rotate in the opposite direction to reset. At this point, the welding rod replacement is completed.

[0097] Preferred embodiments, such as Figure 20 As shown, the inner rod 511 is configured as two sections and the two sections are connected by a spring b519. The purpose of this is to allow the clamping area b to apply flexible clamping to the welding rod through the spring b519.

[0098] A welding method for large spliced ​​pipe fittings, comprising the following steps:

[0099] (I) Placement Stage:

[0100] Step 1: After the welding equipment is moved into the pipe fitting using existing technologies such as the crane boom, the self-connecting device 100 is used to form an adaptive coaxial internal clamping with the inner wall of the pipe fitting. Specifically: the motor 107 is started to reduce the distance between the main frame 101 and the suspension frame 102. Through the cooperation of the connecting rod b105 and the connecting rod a104, the wheel frame 103 is pushed away from the main frame 101 until the rollers 109 set on the wheel frame 103 are in contact with the inner wall of the pipe fitting. At this time, the welding equipment is internally clamped and set in the pipe fitting with the cooperation of the three sets of travel units, and the main frame 101 is coaxially arranged with the pipe fitting. Then, the suspension between the crane boom and the welding equipment is removed.

[0101] Step 2: The traveling unit drives the welding device 200 to move to the welding position of the pipe fitting. Specifically, motor 2 110 drives the roller 109 to rotate with its axis perpendicular to the pipe fitting's axis, and motor 3 111 drives the roller 109 to rotate. This pulls the welding device along the pipe fitting's axis towards the welding position. At the same time, motor 4 112 drives the connecting frame 114 to move through the connecting rod c113. The welding device 200 is connected to the connecting frame 114. The movement of the connecting frame 114 moves the welding device 200 together, bringing the welding device 200 closer to the inner wall of the pipe fitting. The two work together to bring the welding mechanism 400 in the welding device 200 closer to the welding position of the pipe fitting.

[0102] (II) Welding Stage:

[0103] Step 3: The welding mechanism 400 drives the free end of the welding rod to complete the positioning and alignment with the starting point of the area to be welded. Specifically: Motor 6 408 drives the fixed frame 2 406 to move axially along the threaded rod 407. The movement of the fixed frame 2 406 moves the welding unit together with it. At the same time, Motor 7 409 drives the movable frame 1 410 to rotate. The rotation of the movable frame 1 410 moves the welding unit together with it. At the same time, Motor 8 411 drives the movable frame 2 412 to rotate. The rotation of the movable frame 2 412 moves the welding unit together with it. At the same time, Motor 5 402 drives the fixed frame 1 403 to move axially along the pipe fitting. The movement of the fixed frame 1 403 moves the welding unit together with it. Based on this, through the cooperation of Motor 5 402, Motor 6 408, Motor 7 409 and Motor 8 411, the welding unit is driven to move in the three-dimensional coordinate system, which in turn drives the free end of the welding rod held by the welding unit to move in the three-dimensional coordinate system, so that the free end of the welding rod is positioned and aligned with the starting point of the area to be welded.

[0104] Step 4: The welding unit in the welding mechanism 400 begins welding using welding rods. Specifically: the welding clamp is energized, and the traveling unit drives the entire welding equipment to rotate around the axis of the main frame 101, that is, around the axis of the pipe fitting. At the same time, motor 408 drives the welding unit, that is, drives the free end of the welding rod to move along the axial direction of the threaded rod 407 towards the inner wall of the pipe fitting, thereby driving the welding rod to feed. Simultaneously, motor 421 drives the welding unit to oscillate. The welding, feeding, and oscillation of the welding rod work together to simulate the fish-scale welding action and weld the part of the pipe fitting to be welded.

[0105] (III) Replacement Phase:

[0106] Step 5: Motor 5 402 drives synchronous belt group a 401 to move, carrying fixed frame 1 403 and welding unit as a whole to move, so that welding mechanism 400 avoids the movement trajectory of replacement mechanism 500.

[0107] Step Six: The changing mechanism 500 pulls the welding rod to move towards the welding mechanism 400. Specifically, the motor 12 502 drives the synchronous belt group b501 forward one step, so that the welding rod is located in the clamping area b. One step refers to the distance between two adjacent sets of sleeves 503.

[0108] Motor 13 508 drives cam 2 509 to rotate. Since the spring coefficient of coil spring 507 is greater than that of spring a 515, which in turn is greater than that of elastic plate 517, initially, cam 2 509 moves by pushing against the inner rod 511. Through the inclined surface, it pushes against the connecting block 516, causing the two sets of connecting blocks 516 to move away from each other. This, in turn, causes the clamping sections of the two sets of clamping plates 518 to move closer together, closing the clamping area b and clamping the welding rod. The elastic plate 517 is compressed, and at this time, the inner rod 511 contacts the closed end of the outer sleeve column 512. Next, when cam 2 509 pushes against the inner rod 511, because the inner rod 511 contacts the closed end of the outer sleeve column 512, the inner rod 511, outer sleeve column 512, and clamping area b move together. The motor moves to overcome the magnetic attraction of the magnet 504 to the welding rod, and pulls the welding rod out of the sleeve 503. The spring a515 is compressed. After the welding rod is pulled out of the sleeve 503, the end point of the second cam 509 contacts the inner rod 511. At this time, the limiting protrusion 510 restricts the rotation of the second cam 509. The rotating frame 506, the limiting protrusion 510 and the second cam 509 are locked together and can be regarded as a whole. Next, the motor thirteen 508 drives the rotating frame 506 to rotate through the second cam 509 and the limiting protrusion 510. The coil spring 507 is compressed. The parts set on the rotating frame 506 rotate together with the rotating frame 506 until the center line of the clamping area b is parallel to the center line of the clamping area a. The motor thirteen 508 stops running.

[0109] Step 7: Motor 5 402 drives synchronous belt group a 401 to move, moving the fixed frame 1 403 and welding unit as a whole until the center line of clamping area b and the center line of clamping area a are on the same straight line. At this time, motor 5 402 stops running. At this time, the insertion rod 413 is inserted into the insertion hole, and the rotating frame 506 is restricted from rotating.

[0110] Motor 13 508 drives cam 2 509 to rotate in the opposite direction. Because the rotating frame 506 is restricted from rotation, spring a 515 initially releases its elastic force, driving the outer sleeve column 512, inner rod 511, and clamping area b to move in the opposite direction together, pulling the tail end of the welding rod into the clamping area a. Then, motor 13 508 stops running while motor 11 422 runs, causing clamping area a to close and clamp the welding rod. Then, motor 11 422 stops running while motor 13 508 continues running. At this time, elastic plate 517 releases its elastic force, causing clamping area b to open and releasing the clamping of the welding rod. Then, motor 5 402 runs, driving synchronous belt group a 401 to run, carrying the fixed frame 1 403 and the welding unit as a whole to move, avoiding the movement trajectory of the replacement mechanism 500. During this process, the insertion rod 413 leaves the insertion hole. Then, coil spring 507 releases its elastic force, causing the rotating frame 506 to rotate in the opposite direction and reset. At this point, the welding rod replacement is completed.

[0111] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A welding method for large spliced ​​pipe fittings, characterized in that: The welding equipment used includes a self-connecting device and a welding device. The self-connecting device adapts to the pipe diameter and clamps the welding device inside the pipe. It can also move the welding device axially along and around the pipe. The welding device includes a mounting frame connected to the self-connecting device. The mounting frame is equipped with a welding mechanism and a replacement mechanism. The welding mechanism is used to weld the area to be welded on the pipe. The replacement mechanism is used to replace the welding rods of the welding mechanism. It includes the following steps: Step 1: Pull the welding equipment to move it into the pipe fitting, and form an adaptive coaxial internal clamp between the self-connecting device and the inner wall of the pipe fitting; Step 2: The self-connecting device pulls the welding equipment along the axial direction of the pipe fitting toward the welding point. At the same time, the installation components used to connect the self-connecting device and the welding device drive the welding mechanism closer to the welding point. Step 3: The welding mechanism drives the free end of the welding electrode to complete the positioning and alignment with the starting point of the area to be welded; Step 4: The welding unit in the welding mechanism begins to weld using welding rods, and the welding action simulates the fish scale welding action; Step 5: The welding mechanism moves to avoid the movement trajectory of the replacement mechanism; Step Six: Move the welding electrode towards the welding mechanism using the replacement mechanism; Step 7: The welding mechanism moves so that the clamping area a of the welding mechanism holding the welding rod and the clamping area b of the replacement mechanism holding the welding rod are on the same straight line. The replacement mechanism drives the welding rod to move towards the clamping area a. When the tail end of the welding rod is in the clamping area a, the clamping area a closes to clamp the welding rod, and the clamping area b opens to release the welding rod clamping. Then, the welding mechanism moves to avoid the movement trajectory of the replacement mechanism, the replacement mechanism resets, and the welding actions in Step 3 and Step 4 are repeated. The self-connecting device includes a main frame and a suspension frame; The welding mechanism includes a synchronous belt group a and a motor five mounted on a mounting frame. The conveying direction of the synchronous belt group a is parallel to the axial direction of the main frame. The input end of the synchronous belt group a is poweredly connected to the motor five. The synchronous belt in the synchronous belt group a is connected to a fixed frame one. A slide block is mounted on the fixed frame one. A slide rod is slidably mounted on the slide block. The extension direction of the slide rod is perpendicular to the axial direction of the main frame. A fixed frame two is provided at the end of the slide rod. A threaded rod is rotatably mounted on the fixed frame two. The threaded rod is parallel to the slide rod and threadedly connected to the slide block. A motor six is ​​also mounted on the fixed frame two. The motor six is ​​poweredly connected to the threaded rod. A movable frame 1 is rotatably mounted on a fixed frame 2. The axis of rotation of the movable frame 1 is parallel to the extension direction of the slide rod. The input end of the movable frame 1 is connected to a motor 7 mounted on the fixed frame 2. A movable frame 2 is rotatably mounted on the movable frame 1. The axis of rotation of the movable frame 2 is perpendicular to the axis of rotation of the movable frame 1. The input end of the movable frame 2 is connected to a motor 8 mounted on the movable frame 1. The replacement mechanism includes a storage unit mounted on a mounting frame. The storage unit includes a synchronous belt group b and a motor 12 mounted on the mounting frame. The conveying direction of the synchronous belt group b is parallel to the axial direction of the main frame and its input end is connected to the motor 12. A sleeve is provided on the outer surface of the synchronous belt of the synchronous belt group b. A magnet is provided at the lower opening of the sleeve. The welding rod is inserted into the sleeve and attracted by the magnet. Multiple sets of sleeves are arranged in an array along the extension direction of the synchronous belt group b. The replacement mechanism also includes a replacement unit, which includes a support frame mounted on the mounting frame. The support frame and the welding unit are located on the same side of the mounting frame. A rotating frame is rotatably mounted on the support frame, and the axis of rotation of the rotating frame is parallel to the axis of the main frame. A coil spring is provided at the connection between the rotating frame and the support frame. A fixed rod is provided on the rotating frame. In the initial state, the extension direction of the fixed rod is parallel to the axis of the threaded rod. A nut is provided at the free end of the fixed rod. A movable seat is slidably mounted on the outside of the fixed rod. A spring a is sleeved on the outside of the fixed rod between the nut and the movable seat. An outer column is provided on the movable seat. The outer column is parallel to the fixed rod. One end of the outer column is open and connected to the movable seat, and the other end is closed. An inner rod is slidably installed inside the outer column. One end of the inner rod extends into the rotating frame, and the other end is close to the closed end of the outer column. This end is provided with two sets of inclined surfaces. The distance between the two sets of inclined surfaces decreases along the extension direction of the outer column from the open end to the closed end. Two sets of connecting blocks are also provided inside the outer column. The two sets of connecting blocks are located on opposite sides of the two sets of inclined surfaces. The connecting blocks and the outer column form a sliding fit with the guiding direction perpendicular to the conveying direction of the synchronous belt group b. Elastic plates are also provided between the connecting blocks and the outer column. Two sets of elastic plates are provided and located on opposite sides of the two sets of connecting blocks. The replacement unit also includes a clamping plate, which consists of a clamping section and a connecting section. The extension direction of the clamping section is parallel to the conveying direction of the synchronous belt group b. The connecting section is used to connect the clamping section and the connecting block. The clamping plate is provided with two sets of connecting blocks. The free ends of the clamping sections of the two sets of clamping plates form a clamping area b. In the initial state, the center line of the clamping area b coincides with the axis of any sleeve. A motor thirteen is mounted on the support frame. The motor thirteen is arranged coaxially with the axis of rotation of the rotating frame. The output end of the motor thirteen extends into the rotating frame and is equipped with a cam 2. The point of the cam 2 closest to the motor thirteen is the starting point, and the point of the farthest point is the ending point. In the initial state, the starting point of the cam 2 is in contact with the inner rod, and a limiting protrusion is provided on the rotating frame. The limiting protrusion is used to limit the rotation of the cam 2 after the ending point of the cam 2 contacts the inner rod. The movable frame 2 has an extension rod, and the rotating frame is provided with a corresponding matching insertion hole. When the clamping area a and the clamping area b are on the same straight line, the insertion rod is inserted into the insertion hole. The spring constant of the coil spring is greater than that of spring a, which is greater than that of the elastic plate. Step six above: Motor 12 drives synchronous belt group b forward one notch, positioning the welding rod within clamping area b. One notch refers to the distance between two adjacent sets of sleeves. Then, motor 13 drives cam 2 to rotate. Because the spring constant of the coil spring is greater than that of spring a, which in turn is greater than that of the elastic plate, cam 2 initially moves by pushing against the inner rod. This movement, via the inclined plane, pushes against the connecting block, causing the two sets of connecting blocks to move away from each other. Consequently, the clamping sections of the two sets of clamping plates move closer together, clamping area b closes, clamping the welding rod. The elastic plate is compressed, and at this point, the inner rod contacts the closed end of the outer sleeve column. Next, as cam 2 pushes against the inner rod... When the inner rod, outer rod, and clamping area b come into contact with the closed end of the outer sleeve, they move together to overcome the magnetic attraction of the magnet to the welding rod and pull the welding rod out of the sleeve. Spring a is compressed. After the welding rod is pulled out of the sleeve, the end point of cam two comes into contact with the inner rod. At this time, the limiting protrusion restricts the rotation of cam two, and the rotating frame, limiting protrusion, and cam two are locked together. Next, motor thirteen drives the rotating frame to rotate through cam two and the limiting protrusion. The coil spring is compressed, and the parts set on the rotating frame rotate with the rotating frame until the center line of clamping area b is parallel to the center line of clamping area a, at which point motor thirteen stops running.

2. The welding method for a large spliced ​​pipe fitting according to claim 1, characterized in that: One end of the suspension frame extends with a guide rod, the main frame is slidably mounted on the guide rod, and a motor is mounted on the main frame. The motor is a linear lead screw stepper motor, the output shaft of the motor is parallel to the guide rod and the output end is connected to the suspension frame. The self-connecting device also includes a wheel frame, which is connected to the main frame body through a connector. The connector includes a connecting rod a hinged between the main frame body and the wheel frame. Two sets of connecting rods a are arranged along the axial direction of the main frame body. The two sets of connecting rods a are parallel to each other. A connecting rod b is hinged between the suspension frame and the connecting rod a. Multiple sets of wheel frames are arranged in an array along the circumference of the main frame, and each set of wheel frames is equipped with a traveling unit; On the side of the main frame away from the suspension frame, there is also an installation component. The installation component includes a connecting frame. A connecting rod c is hinged between the connecting frame and the main frame. There are two sets of connecting rod c, and the two sets of connecting rod c are parallel to each other. A motor four is installed on the main frame. The hinge shaft formed at the hinge point between the connecting rod c and the main frame is powered by the motor four. The installation frame is connected to the connecting frame.

3. The welding method for a large spliced ​​pipe fitting according to claim 2, characterized in that: The movable frame 2 is equipped with a welding unit. The welding unit includes a fixed frame 3 set on the movable frame 2. The movable frame 3 is rotatably mounted on the fixed frame 3. The axis of rotation of the movable frame 3 is parallel to the axis of rotation of the movable frame 1. A welding frame is rotatably mounted on the movable frame 3. The axis of rotation of the welding frame is parallel to the axis of rotation of the movable frame 2. A slider is slidably installed inside the welding frame, with the sliding direction perpendicular to the axis of rotation of the welding frame. Two sets of sliders are arranged along their own sliding direction. One end of the slider extends to a welding clamp, and two sets of welding clamps are arranged accordingly. The area between the two sets of welding clamps is the clamping area a for holding the welding rod. A motor eleven is installed on the welding frame. The output end of the motor eleven is equipped with a lead screw one. A lead screw seat is installed on the external thread of the lead screw one. The lead screw seat and the welding frame form a sliding fit with the guide direction parallel to the axis of the lead screw one. The axis of the lead screw one is perpendicular to the sliding direction of the slider. The slider is provided with a linkage hole, and the lead screw seat is provided with a protrusion. The linkage hole is arranged at an angle, and the free end of the protrusion slides within the linkage hole.

4. The welding method for a large spliced ​​pipe fitting according to claim 3, characterized in that: A drive unit is installed on the movable frame 2. The drive unit includes a lead screw 2 and a guide rod installed on the movable frame 2. The axes of both are parallel to the axis of rotation of the movable frame 3. The input end of the lead screw 2 is connected to a motor 9. A bracket is installed on the external thread. The bracket and the guide rod form a sliding fit. A motor 10 is installed on the bracket. The axis of the motor 10 is perpendicular to the axis of the lead screw 2. A swing frame is set on the welding frame. A linkage 1 is set between the motor 10 and the swing frame. Linkage component one includes a linkage rod, one end of which is hinged to movable frame two and the other end is hinged to a swing frame ball. Linkage rod is also provided with linkage hole two. The guiding direction of linkage hole two is parallel to the extension direction of linkage rod. The output end of motor ten is provided with cam one. Cam one is provided with protruding pin two. The free end of protruding pin two slides in linkage hole two.

5. The welding method for a large spliced ​​pipe fitting according to claim 4, characterized in that: Step seven above: Motor 5 drives synchronous belt group a to move, moving the fixed frame 1 and welding unit as a whole until the center line of clamping area b and the center line of clamping area a are on the same straight line. At this time, motor 5 stops running. The insertion rod is inserted into the insertion hole, and the rotating frame is restricted from rotating. Motor 13 drives cam 2 to rotate in the opposite direction. Because the rotating frame is restricted from rotating, spring a initially releases its elastic force, driving the outer sleeve, inner rod, and clamping area b to move in the opposite direction together, pulling the tail end of the welding rod into clamping area a. Then, motor 13 stops running while motor 11 runs, causing clamping area a to close and clamp the welding rod. Then, motor 11 stops running while motor 13 continues running. At this time, the elastic plate releases its elastic force, causing clamping area b to open and release the clamping of the welding rod. Then, motor 5 runs, driving synchronous belt group a to run, moving the fixed frame 1 and the welding unit as a whole to avoid the movement trajectory of the changing mechanism. During this process, the insertion rod leaves the insertion hole. Then, the coil spring releases its elastic force, causing the rotating frame to rotate in the opposite direction and reset.

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