Welded pipe welding cantilever supporting device and method

Abstract

The invention provides a welded pipe welding cantilever supporting device and method, and belongs to the technical field of welded pipe machining, the welded pipe welding cantilever supporting device comprises a supporting assembly, a controller and a position sensor, the supporting assembly comprises a supporting head and a driver, and the position sensor is arranged on a moving path of a longitudinal welded pipe and located between the supporting assembly and a supporting wheel; the position sensor is used for sensing the position of the longitudinal welded pipe, the controller is electrically connected with the driver and the position sensor, the controller receives a position signal sent by the position sensor, and the driver drives the supporting head to be switched between the first position and the second position so that the supporting head can avoid the longitudinal welded pipe or abut against the cantilever beam. According to the cantilever supporting device for welding of the welded pipe, the straight welded pipe can be effectively supported before the supporting wheel is separated from the straight welded pipe, and the situation that the cantilever beam is in a free state is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of welded pipe processing, and more specifically, relates to a welded pipe welding cantilever support device and method. Background Art

[0002] The inner weld of the straight seam welded pipe is usually welded by a cantilever welding machine, see Figure 1 The existing cantilever welding machine 1 includes a cantilever beam 11 arranged on a machine body, a welding gun 13 is arranged at the end of the cantilever beam 11 away from the machine body, and a supporting wheel 12 is arranged on the side of the cantilever beam 11 close to the welding gun 13. During operation, a straight rail 3 is arranged on one side of the cantilever welding machine 1, and a welding trolley 4 is arranged on the straight rail 3. The straight seam welded pipe 2 is placed on the welding trolley 4. When welding starts, the welding trolley 4 and the straight seam welded pipe 2 are both located on one side of the cantilever welding machine 1, and the straight seam welded pipe 2 is located at the arc starting position. The cantilever beam 11 passes through the inside of the straight seam welded pipe 2 so that the welding gun 13 corresponds to the arc starting plate, and the supporting wheel 12 abuts against the inner wall of the straight seam welded pipe 2 to support the cantilever beam 11 and keep the cantilever beam 11 stable. After welding starts, the welding trolley 4 drives the straight seam welded pipe 2 to move to the side away from the cantilever welding machine 1. When the welding gun 13 completes the welding operation on the straight seam welded pipe 2, the straight seam welded pipe 2 is in the arc extinguishing position. However, in actual operations, due to the distance between the welding gun and the support wheel, at the end of the welding operation, the support wheel will first fall out of the straight seam welded pipe and lose its supporting effect on the cantilever beam. From then on until the arc is extinguished, the cantilever beam is in a free state. During this welding stage, when external interference occurs, the cantilever beam is prone to shaking, and the welding process cannot be guaranteed to be stable. Summary of the invention

[0003] The purpose of the present invention is to provide a cantilever support device and method for welding a welded pipe, aiming to solve the problem that at the end of the weld welding in a straight seam welded pipe, when the support wheel is separated from the weld pipe, the cantilever beam is in a free state and is easily disturbed by the outside world, the cantilever beam shakes, and the welding gun cannot weld stably.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: to provide a cantilever support device for welding a welded pipe, comprising a support assembly, a controller and a position sensor, wherein the support assembly is arranged on the moving path of the straight seam welded pipe, is located below the cantilever beam, and is on the side of the support wheel away from the welding gun, the support assembly comprises a support head and a driver, the position sensor is arranged on the moving path of the straight seam welded pipe, and is located between the support assembly and the support wheel, and is used to sense the position of the straight seam welded pipe, the controller is electrically connected to the driver and the position sensor respectively, the controller receives a position signal emitted by the position sensor, and controls the driver to drive the support head to switch between a first position and a second position, so that the support head avoids the straight seam welded pipe or abuts the cantilever beam.

[0005] In a possible implementation, fixed plates are provided on both sides of the support head, and the lower end of the support head is rotatably connected between the two fixed plates via a rotating shaft. The driver is a driving motor, which is transmission-connected to the rotating shaft via a reducer and is used to drive the support head to rotate in a vertical plane.

[0006] In one possible implementation, a fixed seat is provided below the support head, the lower end of the support head is hinged on the fixed seat, the driver is a linear driver, the driving end of the linear driver is hinged to the middle part of the support head through a first connecting rod, and is used to drive the support head to rotate in a vertical plane.

[0007] In a possible implementation, a fixed block is provided between the linear drive and the support head, a guide hole is provided on the fixed block along the direction of the position connection line between the linear drive and the support head, an extension section is provided at the driving end of the linear drive, and the extension section passes through the guide hole and is hinged to the first connecting rod.

[0008] In a possible implementation, it is characterized in that a longitudinal groove is provided on the top of the support head, a contact block is slidably provided in the longitudinal groove, the contact block is used for cantilever beam contact, and a coil spring is provided between the contact block and the bottom of the longitudinal groove.

[0009] In a possible implementation, a limiting boss is provided at the bottom of the longitudinal groove, a first reduced diameter section is provided at the lower end of the contact block, and the coil spring is sleeved on the limiting boss and the first reduced diameter section. When the support head is located in the first position, the coil spring supports the contact block, and there is a movable gap between the first reduced diameter section and the limiting boss. When the support head is located in the second position, the coil spring is compressed, and the first reduced diameter section abuts against the limiting boss.

[0010] In one possible implementation, the top of the support head is threadedly connected to an end cover, a avoidance through hole is provided in the middle of the end cover, a second reduced diameter section is provided at the upper end of the contact block, the second reduced diameter section passes through the avoidance through hole and extends to the top of the end cover, and the diameter of the avoidance through hole is smaller than the diameter of the contact block.

[0011] In a possible implementation, a roller is rotatably provided at the upper end of the second reduced diameter section, and the roller is used to contact the cantilever beam.

[0012] In a possible implementation, a through groove is provided at the upper end of the second reduced diameter section, the roller is rotatably connected in the through groove, a brake assembly is provided between the roller and the bottom of the through groove, a through hole is provided at the bottom center of the through groove and penetrates along the length direction of the contact block, the brake assembly includes a brake head and a longitudinal rod connected up and down, the longitudinal rod is slidably penetrated in the through hole and connected to the limiting boss, when the support head is in the first position, there is a braking gap between the brake head and the roller, and when the support head is in the second position, the brake head abuts against the roller to brake the roller.

[0013] The beneficial effect of a cantilever support device for welding a welded pipe provided by the present invention is that compared with the prior art, a cantilever support device for welding a welded pipe provided by the present invention, when the straight seam welded pipe moves from the arc starting position to the arc extinguishing position, when the arc extinguishing end of the straight seam welded pipe passes through the position sensor and the support wheel has not fallen out of the straight seam welded pipe, the controller controls the support assembly to change from a retracted state to an operating state to abut against the cantilever beam to support the cantilever beam, and as the straight seam welded pipe continues to move, before the support wheel has not fallen out of the straight seam welded pipe, the support of the cantilever beam by the support assembly can keep the cantilever beam in a stable state, thereby preventing the cantilever beam from shaking due to external interference, thereby ensuring that the welding gun can perform stable welding.

[0014] The present invention also provides a method for supporting a welded pipe cantilever, which uses the above-mentioned welded pipe cantilever support device, and includes the following steps: the straight seam welded pipe moves from the arc extinguishing position to the arc starting position, and when the arc extinguishing end of the straight seam welded pipe passes the position sensor, the controller controls the support component to retract and avoid the straight seam welded pipe; the straight seam welded pipe moves from the arc starting position to the arc extinguishing position, and when the arc extinguishing end of the straight seam welded pipe passes the position sensor and the support wheel has not yet fallen out of the straight seam welded pipe, the controller controls the support component to move and abut against the support cantilever beam.

[0015] The beneficial effect of a cantilever support method for welding a welded pipe provided by the present invention is that, compared with the prior art, when the straight seam welded pipe moves from the arc starting position to the arc extinguishing position, when the arc extinguishing end of the straight seam welded pipe passes through the position sensor and the support wheel has not fallen out of the straight seam welded pipe, the controller controls the support assembly to change from a retracted state to an operating state to abut against the cantilever beam to support the cantilever beam. As the straight seam welded pipe continues to move, before the support wheel has not fallen out of the straight seam welded pipe, the support assembly supports the cantilever beam, so that the cantilever beam remains in a stable state, thereby preventing the cantilever beam from shaking due to external interference, thereby ensuring that the welding gun can perform stable welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a welding operation state diagram of a cantilever welding machine in the prior art; Figure 2 A state diagram of a straight seam welded pipe in an arc-extinguishing position after the welded pipe welding cantilever support device provided by an embodiment of the present invention is configured at the welding operation site; Figure 3 A state diagram of a straight seam welded pipe in an arc starting position after the welded pipe welding cantilever support device provided by an embodiment of the present invention is configured at the welding operation site; Figure 4 A schematic structural diagram of a support assembly provided in a first embodiment of the present invention; Figure 5 A schematic diagram of the structure of a support assembly provided in a second embodiment of the present invention; Figure 6 A schematic structural diagram of a support assembly provided in a third embodiment of the present invention; Figure 7 A longitudinal cross-sectional view of the support head in the first position in the embodiment provided by the present invention; Figure 8 A longitudinal cross-sectional view of the support head in the second position in the embodiment provided by the present invention.

[0018] Description of reference numerals: 1. Cantilever welding machine; 11. Cantilever beam; 12. Support wheel; 13. Welding gun; 2. Straight seam welded pipe; 3. Straight rail; 31. Bracket; 4. Welding carriage; 5. Support assembly; 51. Support head; 511. Longitudinal groove; 512. Limiting boss; 513. Coil spring; 514. Active gap; 52. Driver; 521. Reducer; 522. Extension section; 53. Rotating shaft; 54. Fixed block; 541. Guide hole; 501. Fixed plate; 502. Fixed seat; 503. First connecting rod; 6. Position sensor; 7. Contact block; 71. First reduced diameter section; 72. Second reduced diameter section; 721. Through groove; 8. End cover; 9. Roller; 101. Brake head; 102. Longitudinal rod; 103. Braking gap. DETAILED DESCRIPTION

[0019] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0020] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0021] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0022] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0023] See also Figures 2 to 3 , a cantilever support device for welding a welded pipe provided by the present invention is now described. The cantilever support device for welding a welded pipe comprises a support assembly 5, a controller and a position sensor 6. The support assembly 5 is arranged on the moving path of the straight welded pipe 2, is located below the cantilever beam 11, and is located on the side of the support wheel 12 away from the welding gun 13. The support assembly 5 comprises a support head 51 and a driver 52. The position sensor 6 is arranged on the moving path of the straight welded pipe 2 and is located between the support assembly 5 and the support wheel 12, and is used to sense the position of the straight welded pipe 2. The controller is electrically connected to the driver 52 and the position sensor 6 respectively. The controller receives the position signal sent by the position sensor 6, and controls the driver 52 to drive the support head 51 to switch between the first position and the second position, so that the support head 51 avoids the straight welded pipe 2 or abuts the cantilever beam 11. In this embodiment, when the support head 51 is in the first position, it is in a retracted state, and when the support head 51 is in the second position, it is in an operating state and abuts against the cantilever beam 11.

[0024] The present invention provides a cantilever support device for welding a welded pipe. Compared with the prior art, when the straight seam welded pipe 2 moves from the arc starting position to the arc extinguishing position, when the arc extinguishing end of the straight seam welded pipe 2 passes through the position sensor and the support wheel 12 has not fallen out of the straight seam welded pipe 2, the controller controls the support assembly 5 to change from a retracted state to an operating state to abut against the cantilever beam 11, thereby supporting the cantilever beam 11. As the straight seam welded pipe 2 continues to move, before the support wheel 12 has not fallen out of the straight seam welded pipe 2, the support assembly 5 supports the cantilever beam 11, so that the cantilever beam 11 is still in a stable state, thereby preventing the cantilever beam 11 from shaking due to external interference, thereby ensuring that the welding gun 13 can perform stable welding.

[0025] In actual operation, at the welding site of the straight seam welded pipe 2, there are two straight rails 3, which are arranged in parallel on one side of the cantilever welding machine 1, and the two straight rails 3 are fixed above the ground by a bracket 31. The welding trolley 4 is set on the two straight rails 3, and the welding trolley 4 is used to move the straight seam welded pipe 2 back and forth between the arc starting position and the arc extinguishing position. The cantilever beam 11 on the cantilever welding machine 1 is on one side of the straight rail 3 and is parallel to the straight rail 3. During the welding operation, the cantilever beam 11 remains in position, and the straight seam welded pipe 2 moves back and forth with the help of the welding trolley 4, so that the cantilever beam 11 passes in and out of the straight seam welded pipe 2.

[0026] In the first embodiment, see Figure 4 The support assembly 5 is arranged between the two straight rails 3, wherein the support head 51 is a column, and fixed plates 501 are arranged on both sides of the support head 51. In the present embodiment, the fixed plates 501 are longitudinal plates fixed to the ground, and the lower end of the support head 51 is rotatably connected between the two fixed plates 501 through a rotating shaft 53. The driver 52 is a driving motor, and one end of the rotating shaft 53 passes through one of the fixed plates 501 and is transmission-connected to the driving motor. When in use, the controller controls the driving motor to rotate the support head 51 in a vertical plane with the aid of the rotating shaft 53. When the support head 51 is in a horizontal state, the support head 51 is in a first position, and the support head 51 can avoid the straight seam welded pipe 2. When the support head 51 is in a vertical state, the support head 51 is in a second position, and the support head 51 abuts against the cantilever beam 11 to support the cantilever beam 11. Optionally, in order to prevent the driving motor from directly driving the rotating shaft 53 and causing the supporting head 51 to move too quickly, a reducer 521 is connected to the driving motor, and the rotating shaft 53 is connected to the driving motor through the reducer 521.

[0027] In the second embodiment, see Figure 5The support assembly 5 is arranged between the two straight rails 3, wherein the support head 51 is a column, a fixed seat 502 is arranged below the support head 51, the fixed seat 502 is fixed on the ground, the lower end of the support head 51 is hinged on the fixed seat 502, the driver 52 is a linear driver, the linear driver is arranged on one side of the support head 51, the driving end of the linear driver is hinged to the middle part of the support head 51 through the first connecting rod 503, with the help of the first connecting rod 503, the linear driver can drive the support head 51 to rotate in the vertical plane, when the support head 51 is in a horizontal state, the support head 51 is in a first position, the support head 51 can avoid the straight seam welded pipe 2, when the support head 51 is in a vertical state, the support head 51 is in a second position, the support head 51 is in contact with the cantilever beam 11, and supports the cantilever beam 11.

[0028] Optional, see Figure 5 A fixing block 54 is provided between the linear driver 52 and the support head 51, and a guide hole 541 is penetrated on the fixing block 54 along the direction of the position connection line of the linear driver 52 and the support head 51. An extension section 522 is provided at the driving end of the linear driver 52, and the extension section 522 penetrates the guide hole 541 and is hinged to the first connecting rod 503. By setting the fixing block 54 and the guide hole 541, the extension section 522 of the linear driver 52 can move stably along the predetermined direction under the constraint of the guide hole 541, so that the driving effect of the linear driver 52 on the support head 51 is stable.

[0029] In the third embodiment, see Figure 6 The support assembly 5 is arranged between the two straight rails 3, wherein the support head 51 is a column, the driver 52 is a screw elevator, the support head 51 is connected to the action end of the screw elevator, and the support head 51 is driven to rise and fall by the screw elevator. When the support head 51 is lowered, the support head 51 is located in the first position, and the support head 51 can avoid the straight seam welded pipe 2. When the support head 51 is raised, the support head 51 is located in the second position, and the support head 51 abuts against the cantilever beam 11 to support the cantilever beam 11.

[0030] In the above example, see Figures 7 and 8When in use, when the driver 52 drives the support head 51 to abut the cantilever beam 11, in order to make the support head 51 support the cantilever beam 11 stably, it is necessary to make the support force applied by the support head 51 to the cantilever beam 11 have a gradually increasing process. Therefore, a longitudinal groove 511 is provided at the top of the support head 51 along the length direction of the support head 51, and a contact block 7 is slidably provided in the longitudinal groove 511. A coil spring 513 is provided between the contact block 7 and the longitudinal groove 511. In order to ensure the stable installation of the spring, a limiting boss 512 is provided at the bottom of the longitudinal groove 511, and a first reduced diameter section 71 is provided at the lower end of the contact block 7. When the contact block 7 is installed in the longitudinal groove 511, the central axis of the first reduced diameter section 71 and the limiting boss 512 coincide, and the coil spring 513 is sleeved on The first reduced diameter section 71 and the limiting boss 512 make the two ends of the coil spring 513 have restrictions and the installation is stable. In use, when the support head 51 is in the first position to avoid the straight seam welded pipe 2, the coil spring 513 supports the contact block 7, and there is a movable gap 514 between the first reduced diameter section 71 and the limiting boss 512. When the support head 51 moves to the second position and finally abuts the cantilever beam 11, the contact block 7 contacts the cantilever beam 11 before the support head 51 moves to the second position. As the support head 51 moves further, the contact block 7 continues to compress the coil spring 513, so that the supporting force of the support head 51 on the cantilever beam 11 gradually increases. When the support head 51 moves to the second position, the first reduced diameter section 71 contacts and abuts the limiting boss 512.

[0031] Optional, see Figure 7 and Figure 8 In order to prevent the contact block 7 from falling out of the longitudinal groove 511, an end cover 8 is threadedly connected to the top of the support head 51, and an avoidance through hole is provided in the middle of the end cover 8. A second reduced diameter section 72 is provided at the upper end of the contact block 7, and the second reduced diameter section 72 passes through the avoidance through hole and extends to the top of the end cover 8, wherein the diameter of the avoidance through hole is smaller than the diameter of the contact block 7. Such an arrangement allows the contact block 7 to only move up and down in the longitudinal groove 511 under the constraint of the end cover 8, and cannot fall out of the longitudinal groove 511.

[0032] In actual application, when the support head 51 is moved from the first position to the second position by rotating, since the contact block 7 will first contact the cantilever beam 11 when the support head 51 reaches the second position, there will be a relative displacement of a certain distance between the contact block 7 and the cantilever beam 11. In order to reduce the friction between the contact block 7 and the cantilever beam 11, a roller 9 is rotatably connected to the upper end of the second reduced diameter section 72. When in use, the roller 9 abuts against the cantilever beam 11, converting the sliding friction into rolling friction, thereby reducing the friction on the cantilever beam 11.

[0033] Further, see Figure 7 and Figure 8A through slot 721 is provided at the upper end of the second reduced diameter section 72, and the roller 9 is rotatably connected in the through slot 721. A brake assembly is provided between the roller 9 and the bottom of the through slot 721. In this embodiment, a through hole penetrating the contact block 7 along the length direction of the contact block 7 is provided at the bottom center of the through slot 721. The brake assembly includes a brake head 101 and a longitudinal rod 102 connected up and down. The longitudinal rod 102 is slidably arranged in the through hole and connected to the limiting boss 512. When the support head 51 is in the first position, there is a brake gap 103 between the brake head 101 and the roller 9. When the support head 51 is in the second position, the brake head 101 abuts against the roller 9 to brake the roller 9. Through the above arrangement, after the roller 9 abuts against the cantilever beam 11, the roller 9 is also in a braking state, so that the abutting relationship between the roller 9 and the cantilever beam 11 is stable.

[0034] The present invention also provides a cantilever support method for welding a welded pipe, which uses the above-mentioned cantilever support device for welding a welded pipe, and comprises the following steps: in the process of the straight seam welded pipe 2 moving from the arc extinguishing position to the arc starting position, when the arc extinguishing end of the straight seam welded pipe 2 passes through the position sensor 6, the controller receives the position signal sent by the position sensor 6, controls the support assembly 5 to be retracted, and makes the support head 51 be in the first position to avoid the straight seam welded pipe 2; in the process of the straight seam welded pipe 2 moving from the arc starting position to the arc extinguishing position, when the arc extinguishing end of the straight seam welded pipe 2 passes through the position sensor 6, at this time, since the position sensor 6 is arranged at a time when the support wheel 12 is close to the cantilever welding machine 1, the support wheel 12 has not yet fallen out of the straight seam welded pipe 2, and at this time, the controller controls the support assembly 5 to move, so that the support head 51 is in the second position, abutting the support cantilever beam 11.

[0035] The present invention provides a cantilever support method for welding a welded pipe. Compared with the prior art, when the straight seam welded pipe 2 moves from the arc starting position to the arc extinguishing position, when the arc extinguishing end of the straight seam welded pipe 2 passes through the position sensor and the support wheel 12 has not fallen out of the straight seam welded pipe 2, the controller controls the support assembly 5 to change from a retracted state to an operating state to abut against the cantilever beam 11, thereby supporting the cantilever beam 11. As the straight seam welded pipe 2 continues to move, after the support wheel 12 has not fallen out of the straight seam welded pipe 2, the support assembly 5 supports the cantilever beam 11, thereby keeping the cantilever beam 11 in a stable state, thereby preventing the cantilever beam 11 from shaking due to external interference, thereby ensuring that the welding gun 13 can perform stable welding.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A cantilever support device for welding a welded pipe, characterized in that: The invention comprises a support assembly (5), a controller and a position sensor (6); the support assembly (5) is arranged on the moving path of the straight seam welded pipe (2), is located below the cantilever beam (11), and is located on the side of the support wheel (12) away from the welding gun (13); the support assembly (5) comprises a support head (51) and a driver (52); the position sensor (6) is arranged on the moving path of the straight seam welded pipe (2), and is located between the support assembly (5) and the support wheel (12), and is used to sense the position of the straight seam welded pipe (2); the controller is electrically connected to the driver (52) and the position sensor (6), respectively; the controller receives a position signal sent by the position sensor (6), and controls the driver (52) to drive the support head (51) to switch between a first position and a second position, so that the support head (51) avoids the straight seam welded pipe (2) or abuts against the cantilever beam (11).

2. A cantilever support device for welding a welded pipe as claimed in claim 1, characterized in that: Fixed plates (501) are provided on both sides of the support head (51); the lower end of the support head (51) is rotatably connected between the two fixed plates (501) via a rotating shaft (53); the driver (52) is a driving motor, which is transmission-connected to the rotating shaft (53) via a reducer (521) and is used to drive the support head (51) to rotate in a vertical plane.

3. A cantilever support device for welding a welded pipe as claimed in claim 1, characterized in that: A fixed seat (502) is provided below the support head (51), and the lower end of the support head (51) is hinged on the fixed seat (502). The driver (52) is a linear driver (52), and the driving end of the linear driver (52) is hinged to the middle part of the support head (51) through a first connecting rod (503), so as to drive the support head (51) to rotate in a vertical plane.

4. A cantilever support device for welding a welded pipe as claimed in claim 3, characterized in that: A fixing block (54) is provided between the linear drive (52) and the supporting head (51); a guide hole (541) is provided on the fixing block (54) along the direction of the position connection line between the linear drive (52) and the supporting head (51); an extension section (522) is provided at the driving end of the linear drive (52); the extension section (522) passes through the guide hole (541) and is hinged to the first connecting rod (503).

5. A cantilever support device for welding a welded pipe as claimed in any one of claims 2 to 4, characterized in that: A longitudinal groove (511) is provided at the top of the support head (51), a contact block (7) is slidably provided in the longitudinal groove (511), the contact block (7) is used for contacting the cantilever beam (11), and a coil spring (513) is provided between the contact block (7) and the bottom of the longitudinal groove (511).

6. A cantilever support device for welding a welded pipe as claimed in claim 5, characterized in that: A limiting boss (512) is provided at the bottom of the longitudinal groove (511), a first reduced diameter section (71) is provided at the lower end of the contact block (7), and the coil spring (513) is sleeved on the limiting boss (512) and the first reduced diameter section (71). When the support head (51) is located at the first position, the coil spring (513) supports the contact block (7), and a movable gap (514) is provided between the first reduced diameter section (71) and the limiting boss (512). When the support head (51) is located at the second position, the coil spring (513) is compressed, and the first reduced diameter section (71) abuts against the limiting boss (512).

7. A cantilever support device for welding a welded pipe as claimed in claim 6, characterized in that: The top of the support head (51) is threadedly connected to an end cover (8), a middle portion of the end cover (8) is provided with an avoidance through hole, the upper end of the contact block (7) is provided with a second reduced diameter section (72), the second reduced diameter section (72) passes through the avoidance through hole and extends to the top of the end cover (8), the diameter of the avoidance through hole is smaller than the diameter of the contact block (7).

8. A cantilever support device for welding a welded pipe as claimed in claim 7, characterized in that: A roller (9) is rotatably provided at the upper end of the second reduced diameter section (72), and the roller (9) is used to contact the cantilever beam (11).

9. A cantilever support device for welding a welded pipe as claimed in claim 8, characterized in that: A through slot (721) is provided at the upper end of the second reduced diameter section (72), and the roller (9) is rotatably connected in the through slot (721). A brake assembly is provided between the roller (9) and the bottom of the through slot (721), and a through hole is provided at the bottom center of the through slot (721) and penetrates along the length direction of the contact block (7). The brake assembly comprises a brake head (101) and a longitudinal rod (102) connected up and down, and the longitudinal rod (102) is slidably arranged in the through hole and connected to the limiting boss (512). When the support head (51) is in the first position, a brake gap (103) is provided between the brake head (101) and the roller (9); when the support head (51) is in the second position, the brake head (101) abuts against the roller (9) to brake the roller (9).

10. A cantilever support method for welding a welded pipe, using the cantilever support device for welding a welded pipe as claimed in any one of claims 1 to 9, characterized in that: The following steps are involved: The straight seam welded pipe (2) moves from the arc extinguishing position to the arc starting position, and when the arc extinguishing end of the straight seam welded pipe (2) passes the position sensor (6), the controller controls the support assembly (5) to retract and avoid the straight seam welded pipe (2); the straight seam welded pipe (2) moves from the arc starting position to the arc extinguishing position, and when the arc extinguishing end of the straight seam welded pipe (2) passes the position sensor (6) and the support wheel (12) has not yet escaped from the straight seam welded pipe (2), the controller controls the support assembly (5) to move to abut against the support cantilever beam (11).

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