Changeable adjustable field welding device

Abstract

The invention provides a changeable adjustable field welding device, which relates to the technical field of welding and comprises a movable welding seat and a movable positioning clamp. According to the movable positioning clamp, through the spiral distribution design of the crank arm lever and the centering roller, progressive clamping force can be synchronously applied from 12 directions, the axis of a pipeline is automatically centered, the centering precision is high, compared with a traditional manual clamp, manual repeated adjustment is not needed, automatic centering and clamping are achieved, the welding precision is improved, and the production efficiency is improved. The coaxiality of pipeline butt joint is remarkably improved, the weld joint alignment tolerance is reduced, the welding quality is guaranteed, rotation of the driving lead screw is achieved through worm and gear transmission, synchronous belt transmission and composite motion of a lead screw nut, and meanwhile rotary centering of the rotary inner ring and axial feeding of the movable positioning clamp are achieved. According to the integrated design, clamping and butt joint processes of traditional step-by-step operation are combined, the operation efficiency is obviously improved, and the device is particularly suitable for rapid assembly of large-diameter pipelines.

Description

Technical Field

[0001] The present invention relates to the field of welding technology, and particularly to a variable and adjustable on-site welding device. Background Art

[0002] As a key technology in industrial infrastructure construction, pipeline welding is applied in multiple fields such as energy, chemical industry, and electric power. With the progress of industrial technology, pipeline welding is developing towards automation, intelligence, and high adaptability to cope with complex working conditions and strict quality requirements, providing a solid guarantee for global infrastructure construction.

[0003] Existing pipeline welding technologies have many limitations. Traditional manual welding has a high dependence on manual operation, low efficiency, high labor intensity, and the welding quality is significantly affected by the experience of workers, prone to weld defects. Moreover, in fields such as petroleum and chemical industry, millimeter-level precision centering and docking are required for pipeline welding. The traditional alignment method is to use measuring tools such as calipers for manual measurement and alignment, and then use tooling for clamping and positioning, which is not only inefficient but also difficult to guarantee the accuracy. Summary of the Invention

[0004] The purpose of the present invention is to provide a variable and adjustable on-site welding device to solve the problems that the traditional pipeline welding alignment is not only inefficient but also difficult to guarantee the accuracy as mentioned in the above background.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is a variable and adjustable on-site welding device, which includes a mobile welding base. A welding workbench equipped with a handheld welding torch is fixedly connected to the mobile welding base. Two groups of linear guide rails are arranged on the welding workbench. A linear slider is slidably connected to the linear guide rail, and a mobile positioning fixture is fixedly connected to the linear slider; A driving lead screw is arranged between the two groups of linear guide rails. The driving lead screw is rotatably connected to the welding workbench through a bearing seat. A worm gear is fixedly connected to the midpoint of the driving lead screw. A worm that meshes with the worm gear is rotatably connected inside the mobile welding base. One end of the worm extends out of the mobile welding base and is connected to a handwheel; The mobile positioning fixture includes a clamping ring. A rotating inner ring is rotatably connected inside the clamping ring. The rotating inner ring is rotatably connected to twelve groups of curved arm levers through a rotating shaft. One end of each group of curved arm levers is rotatably connected to a centering roller. One end of the curved arm lever is fixedly connected to a sliding rod. The curved arm lever is connected to the symmetric curved arm lever on the other side through the sliding rod. The clamping ring is provided with a limiting groove for the sliding rod to penetrate through; An outer edge driving tooth is arranged at the bottom of the rotating inner ring, and the bottom of the clamping ring is rotatably connected to a driving gear meshing with the outer edge driving tooth. A driven pulley is fixedly connected to one side of the driving gear, and the driven pulley is connected to the driving pulley through a transmission belt. The driving pulley is fixedly connected to a lead screw nut, and the lead screw nut is rotatably connected to the mobile positioning fixture, and the lead screw nut cooperates with the driving lead screw thread.

[0006] Furthermore, two sets of linear guides are arranged in parallel on the welding workbench, and two linear sliders are slidably connected on each set of linear guides. The linear sliders located at the same end of the two sets of linear guides are jointly connected to a set of movable positioning fixtures, and the two sets of movable positioning fixtures are symmetrically distributed with the midpoint line of the linear guides as the symmetry axis.

[0007] Furthermore, the linear guide rail is fixed to the positioning groove of the welding workbench by T-bolts, and the parallelism error of the guide rail is ≤0.02mm. The two linear sliders on each set of linear guide rails are connected to the mounting seat bolts at the bottom of the mobile positioning fixture to form a double slider support structure.

[0008] Furthermore, the driving screw is divided into two equal sections from the midpoint, and the thread directions of the two sections of the screw are opposite. When matched with the screw nut, the driving screw can rotate to make the two sets of mobile positioning fixtures move synchronously towards or away from each other.

[0009] Furthermore, the worm wheel and the worm form a worm gear transmission pair, and the lead angle of the worm is smaller than the equivalent friction angle, forming a reverse self-locking function to ensure that the driving screw locks the pipeline position when it stops rotating.

[0010] Furthermore, the twelve groups of crank arm levers are symmetrically distributed on both sides of the rotating inner ring in groups of six, and the crank arm levers on the same side are evenly arranged according to the Archimedean spiral. The centering rollers generate progressive radial pressure during clamping to achieve automatic centering of the pipeline axis.

[0011] Furthermore, the outer edge driving teeth are one eighth of the complete gear, and the driving gear only meshes with the outer edge driving teeth within a range of 45° when rotating, thereby limiting the maximum rotation angle of the rotating inner ring and avoiding over-clamping.

[0012] Furthermore, the transmission belt is a trapezoidal tooth synchronous belt, and the active pulley and the lead screw nut are interference fit. When the lead screw is driven to rotate, the rotation of the lead screw nut is converted into the rotation of the driving gear through the transmission belt, thereby realizing the linkage between the rotating inner ring and the mobile positioning fixture.

[0013] Furthermore, the centering roller is a polyurethane-coated roller with a surface hardness of Shore A80, which can not only protect the pipe surface but also provide sufficient friction to ensure clamping stability.

[0014] Furthermore, the movable welding seat adopts a Q355B steel frame, and triangular stiffeners are arranged inside the movable welding seat. The surface of the welding workbench is machined by grinding to IT7 precision, ensuring that the flatness error of the installation reference surface of the linear guide rail is ≤0.05 mm.

[0015] Compared with the prior art, the beneficial effects of the present invention include: For a variable adjustable on-site welding device proposed by the present invention, through the spiral distribution design of the curved arm lever and centering roller of the movable positioning fixture, progressive clamping forces can be applied synchronously from 12 directions, enabling the automatic centering of the pipe axis with a centering accuracy of ≤0.1 mm. Compared with traditional manual fixtures, there is no need for manual repeated adjustment, realizing automatic centering and clamping, improving welding accuracy, significantly enhancing the coaxiality of pipe docking, reducing the weld misalignment amount, and ensuring welding quality.

[0016] For a variable adjustable on-site welding device proposed by the present invention, the rotation of the driving lead screw realizes the rotational centering of the rotating inner ring and the axial feeding of the movable positioning fixture through the compound motion of worm and worm gear transmission, synchronous belt transmission, and lead screw nut. This integrated design combines the traditional step-by-step clamping and docking processes, improving the operation efficiency by more than 50%, and is particularly suitable for the rapid assembly of large-diameter pipes. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematically shows the external structure diagram of a variable adjustable on-site welding device proposed according to an embodiment of the present invention; Figure 2 Schematically shows the structure diagram of the worm and worm gear of a variable adjustable on-site welding device proposed according to an embodiment of the present invention; Figure 3 Schematically shows the structure diagram of the driven belt pulley and the driving belt pulley of a variable adjustable on-site welding device proposed according to an embodiment of the present invention; Figure 4 Schematically shows the structure diagram of the lead screw nut and the driving belt pulley of a variable adjustable on-site welding device proposed according to an embodiment of the present invention; Figure 5 Schematically shows the front view structure diagram of the movable positioning fixture of a variable adjustable on-site welding device proposed according to an embodiment of the present invention; Figure 6 Schematically shows the sectional view structure diagram of the movable positioning fixture of a variable adjustable on-site welding device proposed according to an embodiment of the present invention; Figure 7 Schematically shows the relaxed state structure diagram of the movable positioning fixture of a variable adjustable on-site welding device proposed according to an embodiment of the present invention; Figure 8 Schematically shows a structural schematic diagram of the clamping state of a movable positioning fixture of a multi-variant adjustable on-site welding device proposed according to an embodiment of the present invention.

[0018] Reference numerals in the figure: 1, movable welding seat; 2, welding workbench; 3, linear guide rail; 4, linear slider; 5, movable positioning fixture; 6, driving lead screw; 7, worm gear; 8, worm; 9, handwheel; 10, clamping ring; 1001, limit groove; 11, rotating inner ring; 1101, rotating shaft; 12, curved arm lever; 13, centering roller; 14, sliding rod; 15, outer edge driving tooth; 16, driving gear; 17, driven pulley; 18, driving pulley; 19, transmission belt; 20, lead screw nut. Specific embodiments

[0019] It is easy to understand that according to the technical solution of the present invention, without changing the essence of the present invention, those of ordinary skill in the art can propose various interchangeable structural forms and implementation methods. Therefore, the following specific embodiments and the accompanying drawings are only exemplary descriptions of the technical solution of the present invention, and should not be regarded as all of the present invention or as a limitation or restriction on the technical solution of the present invention.

[0020] Combined with the embodiments of the present invention Figure 1-8 Shown.

[0021] Embodiment 1: A multi-variant adjustable on-site welding device includes a movable welding seat 1. The movable welding seat 1 is welded from Q355B high-strength low-alloy structural steel, and triangular stiffeners are arranged inside its frame to ensure both structural stiffness and reduce the overall weight. The welding workbench 2 is fixed to the top surface of the movable welding seat 1 through four anchor bolts. The surface of the workbench is ground to IT7 precision to ensure that the flatness error of the installation reference surface of the linear guide rail 3 is less than 0.05 mm. Two groups of linear guide rails 3 adopt HGH20CA high-precision linear guide rails of HIWIN brand. The guide rails are installed in cooperation with the positioning grooves on the workbench through T-bolts. The distance between the guide rails is precisely adjusted by a laser calibration system to ensure that the parallelism error is controlled within ±0.02 mm, and a handheld welding torch is configured on the welding workbench 2.

[0022] Two linear sliders 4 are configured on each group of linear guide rails 3. The sliders adopt self-lubricating design and are internally provided with 28 precision balls with a diameter of φ6 mm. The clearance between the sliders and the guide rails is controlled within the range of 0.01 - 0.03 mm. The sliders at the same end on the two groups of guide rails are connected to the mounting seat at the bottom of the movable positioning fixture 5 through a connecting plate made of Q235 steel plate with a thickness of 12 mm. The connecting plate and the sliders are fixed with M8×30 high-strength bolts, and the pre-tightening force of the bolts is controlled at 45 - 50 N·m by a torque wrench to ensure connection rigidity.

[0023] The driving lead screw 6 is selected as the SFU2005 type ball screw. The material of the lead screw is GCr15 bearing steel, and its surface is quenched to HRC58 - 62, effectively improving wear resistance. The lead screw is installed on the bottom surface of the welding table 2 through two LMF12UU type bearing seats. The bearing seats adopt double - row angular contact ball bearings, which can bear radial loads and a certain axial load. The mid - point of the lead screw is connected to the worm gear 7 through an 8 - mm - thick double - key groove. The worm gear 7 is made of ZCuSn10Pb1 tin bronze material, with a module of 3 and 40 teeth, forming a worm - gear pair with a transmission ratio of 1:40 with the worm 8.

[0024] The worm 8 passes through the through - hole at the bottom of the moving welding seat 1 and is supported by two 7205C type angular contact ball bearings. The pre - tightening force of the bearings is precisely controlled by adjusting shims. The extending end of the worm 8 is fixed to the handwheel 9 through a taper pin. The handwheel 9 is made of engineering plastic, with anti - slip patterns designed on its surface. The handwheel 9 with a diameter of 150 mm can provide a comfortable operating torque. The self - locking characteristic of the worm - gear drive ensures that when the operation stops, the driving lead screw 6 is automatically locked to prevent pipeline displacement.

[0025] The clamping ring 10 of the moving positioning fixture 5 is cast from QT450 - 10 ductile iron, and the internal stress is eliminated through aging treatment. Its inner side is connected to the rotating inner ring 11 through two 6208 type deep - groove ball bearings. The bearing clearance is controlled within 0.02 - 0.04 mm to ensure flexible rotation. 12 groups of curved - arm levers 12 are evenly distributed on the circumferential surface of the rotating inner ring 11. Each group of levers is hinged to the rotating inner ring 11 through a φ10 - mm rotating shaft 1101. The material of the levers is 6061 - T6 aluminum alloy, and its corrosion resistance is enhanced through anodic oxidation treatment.

[0026] One end of the curved - arm lever 12 is installed with a centering roller 13. The centering roller 13 is a polyurethane - coated roller with φ50 mm×20 mm, and the hardness of the coated layer is Shore A80, which not only protects the pipeline surface but also provides sufficient friction coefficient. The centering roller 13 is installed at the lever end through two miniature deep - groove ball bearings and can rotate freely to adapt to different rotational speeds of the pipeline. The other end of the curved - arm lever 12 is fixedly connected with a sliding rod 14. A limiting groove 1001 is opened on the clamping ring 10. The sliding rod 14 passes through the limiting groove 1001 and is connected to the curved - arm lever 12 on the other side of the rotating inner ring 11. The 12 groups of curved - arm levers 12 are symmetrically distributed on both sides of the rotating inner ring 11 in groups of 6. The 6 groups of levers on the same side are arranged in an Archimedean spiral, with a spiral angle of 15°. This layout enables the centering roller 13 to generate a progressive radial pressure during the clamping process, ensuring that the pipeline axis is centered with an accuracy of ≤0.1 mm.

[0027] The outer edge drive teeth 15 at the bottom of the rotating inner ring 11 are sector gears custom - processed with a module of 2, 10 teeth, and only 1 / 8 of a complete gear is retained. The drive gear 16 is installed at the bottom of the clamping ring 10 through a pin shaft. The gear has a module of 2 and 20 teeth, forming a non - continuous meshing drive with the outer edge drive teeth 15. When the drive gear 16 rotates, it drives the rotating inner ring 11 to rotate only within the 1 / 8 circumferential range in contact with the outer edge drive teeth 15, thus strictly limiting the rotation angle within 45°, avoiding mechanism damage caused by excessive rotation.

[0028] The driven pulley 17 coaxially installed with the drive gear 16 is driven by the drive pulley 18 through the HTD - 3M - 24 drive belt 19. The length of the synchronous belt is 120 mm, and the pre - tension force is adjusted to 150 N through a tensioning pulley. The center hole of the drive pulley 18 has an interference fit with the lead screw nut 20. The lead screw nut 20 uses the KBS2005 type ball nut of the KSS brand and forms a ball screw pair with a lead of 5 mm with the drive lead screw 6. When the drive lead screw 6 rotates, the lead screw nut 20 not only rotates with the lead screw but also drives the drive gear 16 to rotate at a transmission ratio of 2:1 through the drive belt 19, thereby achieving precise rotation control of the rotating inner ring 11.

[0029] Embodiment 2: A variable - type adjustable on - site welding device, including a mobile welding base 1. The mobile welding base 1 is welded from Q355B high - strength low - alloy structural steel, and triangular stiffeners are arranged inside its frame to ensure structural stiffness and reduce the overall weight. The welding workbench 2 is fixed to the top surface of the mobile welding base 1 through four anchor bolts. The surface of the workbench is ground to an IT7 - level precision to ensure that the flatness error of the installation reference surface of the linear guide 3 is less than 0.05 mm. The two groups of linear guides 3 use the HGH20CA high - precision linear guides of the HIWIN brand. The guides are installed in cooperation with the positioning grooves on the workbench through T - shaped bolts. The distance between the guides is precisely adjusted by a laser calibration system to ensure that the parallelism error is controlled within ±0.02 mm.

[0030] Each group of linear guides 3 is equipped with two linear sliders 4. The sliders adopt a self - lubricating design and are internally provided with 28 precision balls with a diameter of φ6 mm. The fit clearance between the sliders and the guides is controlled within the range of 0.01 - 0.03 mm. The sliders at the same end of the two groups of guides are connected to the mounting seat at the bottom of the mobile positioning fixture 5 through a connecting plate made of Q235 steel plate with a thickness of 12 mm. The connecting plate and the sliders are fixed with M8×30 high - strength bolts, and the pre - tightening force of the bolts is controlled within 45 - 50 N・m by a torque wrench to ensure connection rigidity.

[0031] The driving lead screw 6 is selected as the SFU2005 type ball screw. The material of the lead screw is GCr15 bearing steel, and its surface is quenched to HRC58 - 62, effectively improving wear resistance. The lead screw is installed on the bottom surface of the welding workbench 2 through two LMF12UU type bearing seats. The bearing seats adopt double - row angular contact ball bearings, which can bear radial loads and a certain axial load. The mid - point of the lead screw is connected to the worm wheel 7 through an 8 - mm - thick double - keyway. The worm wheel 7 is made of ZCuSn10Pb1 tin bronze material, with a module of 3 and 40 teeth, forming a worm - and - worm - wheel pair with a transmission ratio of 1:40 with the worm 8.

[0032] The worm 8 passes through the through - hole at the bottom of the moving welding seat 1 and is supported by two 7205C type angular contact ball bearings. The pre - tightening force of the bearings is precisely controlled by adjusting shims. At the welding operation site with a stable power supply, we can introduce a reduction motor drive system, which can significantly improve the automation level and operation efficiency of the device. Therefore, the extended end of the worm 8 can be fixedly connected to the reduction motor through a taper pin. The Delta ECMA - C20807RS type servo reduction motor is selected, with a rated power of 0.75 kW and a rated speed of 3000 rpm, and is paired with a PLF60 - 10 planetary reducer, whose reduction ratio is 1:10, and the output torque can reach 23.8 N·m. The motor is fixed to the bottom of the moving welding seat 1 through a customized flange mounting seat. The mounting seat is welded with Q345B steel plate with a thickness of 12 mm, and the connecting bolts with the moving welding seat 1 are M16 high - strength bolts, and the pre - tightening force is controlled at 80 - 100 N·m. The output shaft of the motor is directly connected to the worm 8 through a diaphragm coupling. The torsional stiffness of the coupling reaches 50 N·m / rad, and the axial compensation amount is ±2 mm, ensuring high - precision power transmission and low vibration. The self - locking characteristic of the worm - and - worm - wheel drive ensures that when the operation stops, the driving lead screw 6 is automatically locked to prevent pipeline displacement.

[0033] It is necessary to strengthen the worm 8. The worm 8 adopts the 20CrMnTi carburizing and quenching process, the tooth surface hardness is increased to HRC58 - 62, the module is increased from 3 in the original embodiment to 4, and the lead angle is optimized to 12° to match the high - speed rotation characteristics of the servo motor. The worm support bearings are upgraded to tapered roller bearings, which can bear both radial and axial loads, improving the rigidity and service life of the drive system.

[0034] An electric control box with an IP65 protection level is set on the side of the moving welding seat 1, which contains a Siemens S7 - 1500 PLC controller, a Schneider Lexium32 servo driver and a relay module. The PLC communicates with the servo driver through the PROFINET bus to achieve precise closed - loop control of the motor speed and displacement. The system is equipped with a high - precision absolute encoder, which is installed at the end of the worm 8, with a resolution of 2500 lines / rev, and can real - time feedback the rotation angle of the driving lead screw 6.

[0035] The operation interface adopts the Weilin MT8102iE touch screen, which integrates functions such as pipeline diameter selection, clamping force setting, and feed speed adjustment. The operator can input the specification parameters of the pipeline to be welded through the interface, and the system automatically calculates the required number of motor rotation turns, clamping pressure threshold, and feed rate, realizing an intelligent operation process. After starting the system, the servo motor drives the worm 8 to rotate according to the preset parameters, and drives the driving lead screw 6 to rotate after being decelerated by the worm gear 7. The axial displacement of the lead screw nut 20 is transmitted through the transmission belt 19 to convert it into the rotation of the driving gear 16, thereby controlling the centering clamping action of the rotating inner ring 11. The encoder monitors the lead screw speed in real time, and the servo driver dynamically adjusts the motor output according to the feedback signal to ensure that the pipeline centering accuracy is ≤0.03mm.

[0036] The clamping ring 10 of the mobile positioning fixture 5 is cast from QT450-10 ductile iron, and the internal stress is eliminated by aging treatment. Its inner side is connected to the rotating inner ring 11 through two 6208 deep groove ball bearings, and the bearing clearance is controlled within 0.02 - 0.04mm to ensure flexible rotation. 12 groups of curved arm levers 12 are evenly distributed on the circumferential surface of the rotating inner ring 11. Each group of levers is hinged to the rotating inner ring 11 through a φ10mm rotating shaft 1101. The lever material is 6061-T6 aluminum alloy, and its corrosion resistance is enhanced by anodic oxidation treatment.

[0037] The mobile positioning fixture 5 is integrated with a strain type pressure sensor to monitor the clamping force of the centering roller 13 on the pipeline in real time. When the pressure reaches the set value, the PLC controller triggers the servo motor to decelerate, and drives the lead screw nut 20 to feed at a low speed of 0.1mm / s until the pipeline end faces contact. At the same time, the laser displacement sensor on the linear guide 3 monitors the fixture spacing in real time to ensure the axial butt joint accuracy of ±0.1mm.

[0038] One end of the curved arm lever 12 is installed with a centering roller 13. The centering roller 13 is a polyurethane coated roller with φ50mm×20mm, and the hardness of the coated layer is Shore A80, which not only protects the pipeline surface but also provides sufficient friction coefficient. The centering roller 13 is installed at the lever end through two miniature deep groove ball bearings and can rotate freely to adapt to different rotation speeds of the pipeline. The other end of the curved arm lever 12 is fixedly connected with a sliding rod 14. A limiting groove 1001 is opened on the clamping ring 10. The sliding rod 14 passes through the limiting groove 1001 and is connected to the curved arm lever 12 on the other side of the rotating inner ring 11. The 12 groups of curved arm levers 12 are symmetrically distributed on both sides of the rotating inner ring 11 in groups of 6. The 6 groups of levers on the same side are arranged in an Archimedean spiral, and the spiral angle is 15°. This layout makes the centering roller 13 generate a progressive radial pressure during the clamping process, ensuring that the pipeline axis is centered with an accuracy of ≤0.1mm.

[0039] The outer edge drive teeth 15 at the bottom of the rotating inner ring 11 are sector gears custom - processed with a module of 2, 10 teeth, and only 1 / 8 of a complete gear is retained. The drive gear 16 is installed at the bottom of the clamping ring 10 through a pin shaft. The gear has a module of 2 and 20 teeth, forming a non - continuous meshing drive with the outer edge drive teeth 15. When the drive gear 16 rotates, it drives the rotating inner ring 11 to rotate only within the 1 / 8 circumferential range in contact with the outer edge drive teeth 15, thus strictly limiting the rotation angle within 45° to avoid damage to the mechanism caused by excessive rotation.

[0040] The driven pulley 17 coaxially installed with the drive gear 16 is driven by the drive pulley 18 through the HTD - 3M - 24 drive belt 19. The length of the synchronous belt is 120 mm, and the pre - tension force is adjusted to 150 N through the tensioning pulley. The central hole of the drive pulley 18 has an interference fit with the lead screw nut 20. The lead screw nut 20 uses the KBS2005 type ball nut of the KSS brand, forming a ball screw pair with a lead of 5 mm with the drive lead screw 6. When the drive lead screw 6 rotates, the lead screw nut 20 not only rotates with the lead screw but also drives the drive gear 16 to rotate at a transmission ratio of 2:1 through the drive belt 19, thereby achieving precise rotation control of the rotating inner ring 11. Working principle: The working process of this device can be divided into two cooperative stages: First, the worm 8 drives the worm wheel 7 to rotate, driving the drive lead screw 6 to rotate at a speed of 15 rpm. The lead screw nut 20 generates an axial displacement under the action of the lead screw rotation, and through the transmission of the drive belt 19, the drive gear 16 rotates at a speed of 30 rpm, further driving the rotating inner ring 11 to rotate at a speed of 15 rpm. The rotation of the rotating inner ring 11 is converted into the radial feeding movement of the centering rollers 13 through the crank - arm lever 12. The 12 centering rollers 13 clamp the pipe synchronously from 12 directions, and the spiral - arranged lever mechanism makes the centering pressure gradually increase from the outside to the inside to ensure the automatic centering of the pipe axis.

[0041] When the pipe is completely clamped, the centering rollers 13 receive the reaction force from the outer wall of the pipe, which is transmitted to the rotating inner ring 11 through the crank - arm lever 12, preventing it from further rotating, thus locking the position of the rotating inner ring 11. At this time, the continuous rotation of the drive lead screw 6 will cause the lead screw nut 20 to generate a linear displacement along the lead screw, driving the two groups of moving positioning jigs 5 to move towards each other at a speed of 0.5 mm / s through the linear guide 3, realizing the axial butt - joint of the welding end faces of the pipe. During the whole process, the self - locking characteristic of the worm - gear drive ensures that the pipe remains in a stable clamping state when stopped at any position.

[0042] The technical scope of the present invention is not limited to the content described above. Those skilled in the art can make various deformations and modifications to the above - mentioned embodiments without departing from the technical idea of the present invention, and these deformations and modifications should all fall within the protection scope of the present invention.

Claims

1. A variable and adjustable on-site welding device, characterized in that: The invention comprises a movable welding seat (1), a welding workbench (2) equipped with a handheld welding gun being fixedly connected to the movable welding seat (1), two sets of linear guide rails (3) being arranged on the welding workbench (2), a linear slide block (4) being slidably connected to the linear guide rail (3), and a movable positioning fixture (5) being fixedly connected to the linear slide block (4); A driving screw (6) is arranged between the two groups of linear guide rails (3), and the driving screw (6) is rotatably connected to the welding workbench (2) via a bearing seat, a worm wheel (7) is fixedly connected to the midpoint of the driving screw (6), a worm (8) meshing with the worm wheel (7) is rotatably connected inside the movable welding seat (1), and one end of the worm (8) extends out of the movable welding seat (1) and is connected to a hand wheel (9); The movable positioning fixture (5) comprises a clamping ring (10), wherein a rotating inner ring (11) is rotatably connected inside the clamping ring (10), and the rotating inner ring (11) is rotatably connected to twelve groups of crank arm levers (12) via a rotating shaft (1101), and one end of each group of crank arm levers (12) is rotatably connected to a centering roller (13), and the other end of the crank arm lever (12) is fixedly connected to a sliding rod (14), and the crank arm lever (12) is connected to a symmetrical crank arm lever (12) on the other side via the sliding rod (14), and the clamping ring (10) is provided with a limiting groove (1001) for the sliding rod (14) to pass through; The bottom of the rotating inner ring (11) is provided with an outer edge driving tooth (15); the bottom of the clamping ring (10) is rotatably connected to a driving gear (16) meshing with the outer edge driving tooth (15); one side of the driving gear (16) is fixedly connected to a driven pulley (17); the bottom of the movable positioning fixture (5) is rotatably connected to a lead screw nut (20); the lead screw nut (20) is threadably matched with the driving lead screw (6); the lead screw nut (20) is fixedly connected to a driving pulley (18); and the driven pulley (17) is transmission-connected to the driving pulley (18) via a transmission belt (19).

2. A variable and adjustable on-site welding device as claimed in claim 1, characterized in that: The two groups of linear guide rails (3) are arranged in parallel, and two linear sliders (4) are slidably connected to each group of linear guide rails (3). The linear sliders (4) located at the same end of the two groups of linear guide rails (3) are commonly connected to a group of movable positioning fixtures (5), and the two groups of movable positioning fixtures (5) are symmetrically distributed with the midpoint line of the linear guide rails (3) as the symmetry axis.

3. A variable and adjustable on-site welding device as claimed in claim 1, characterized in that: The linear guide rails (3) are fixed to the positioning grooves of the welding workbench (2) by means of T-bolts, and the two linear slide blocks (4) on each set of the linear guide rails (3) are connected to the mounting seat bolts at the bottom of the movable positioning fixture (5).

4. A variable and adjustable on-site welding device as claimed in claim 1, characterized in that: The driving screw (6) is equally divided into two sections from the midpoint, and the thread directions of the two sections are opposite.

5. A variable and adjustable on-site welding device as claimed in claim 1, characterized in that: The worm wheel (7) and the worm (8) form a worm gear transmission pair, and the lead angle of the worm (8) is smaller than the equivalent friction angle.

6. A variable and adjustable on-site welding device as claimed in claim 1, characterized in that: The twelve groups of crank levers (12) are symmetrically distributed on both sides of the rotating inner ring (11) in groups of six, and the crank levers (12) on the same side are evenly arranged according to the Archimedean spiral.

7. A variable and adjustable on-site welding device as claimed in claim 1, characterized in that: The outer edge driving teeth (15) are one eighth of a complete gear, and the driving gear (16) only meshes with the outer edge driving teeth (15) within a range of 45° when rotating.

8. A variable and adjustable on-site welding device as claimed in claim 1, characterized in that: The transmission belt (19) is a trapezoidal tooth synchronous belt, and the driving pulley (18) and the screw nut (20) are in interference fit.

9. A variable and adjustable on-site welding device as claimed in claim 1, characterized in that: The centering roller (13) is a polyurethane rubber-coated roller.

10. A variable and adjustable on-site welding device as claimed in claim 1, characterized in that: The movable welding seat (1) adopts a Q355B steel frame, triangular reinforcing ribs are arranged inside the movable welding seat (1), and the surface of the welding workbench (2) is ground to IT7 level accuracy.

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