Electric welding device with built-in nut

Abstract

A kind of electric welding device of round tube built-in nut, including support, support includes base, vertical support is fixed above base, the upper end of vertical support is fixedly connected with horizontal support, nut blanking mechanism is fixed above horizontal support, the lower end of nut blanking mechanism is connected with nut positioning mechanism, nut enters nut positioning mechanism by blanking mechanism, round tube fixing mechanism is arranged in front of nut positioning mechanism, nut positioning mechanism can move in horizontal direction, push nut to specified position in round tube, left welding mechanism and right welding mechanism are arranged on the both sides of round tube fixing mechanism, left welding mechanism and right welding mechanism can simultaneously contact outer surface with round tube, and welding is carried out to round tube and its built-in nut.

Description

Technical Field

[0001] This utility model belongs to the field of electric welding equipment, and specifically relates to an electric welding device for a round tube with an internal nut. Background Technology

[0002] Welded nuts are common components in modern industry. Welding nuts inside pipes is a common process. After welding, the nut becomes integrated with the pipe wall, improving the tensile, torsional, and shear strength of the connection, preventing threads from loosening or falling off, and also saving space and improving aesthetics. However, current technology involves manually placing the nut inside the round pipe and then welding it from the outside using an electric welding machine. This manual method is not only inefficient but also prone to inaccurate positioning, contamination of the nut surface, and weak welds. Summary of the Invention

[0003] The main purpose of this invention is to solve the problems of low efficiency in the production of welded nuts inside round tubes, which easily leads to inaccurate welding positioning and weak welding.

[0004] This utility model provides an electric welding device for a nut inside a round tube, including a bracket, a base, a vertical bracket fixed above the base, a horizontal bracket fixedly connected to the upper end of the vertical bracket, a nut feeding mechanism fixed above the horizontal bracket, and a nut feeding mechanism connected at the lower end of the nut feeding mechanism to a nut positioning mechanism. The nut enters the nut positioning mechanism through the nut feeding mechanism. A round tube fixing mechanism is provided in front of the nut positioning mechanism. The nut positioning mechanism can move horizontally to push the nut to a designated position inside the round tube. A left welding mechanism and a right welding mechanism are provided on both sides of the round tube fixing mechanism. The left welding mechanism and the right welding mechanism can simultaneously contact the round tube and weld the round tube and its built-in nut. The nut positioning mechanism, the round tube fixing mechanism, the left welding mechanism, and the right welding mechanism are respectively fixed on the vertical bracket.

[0005] Furthermore, the nut feeding mechanism includes a centrifuge mounted on a horizontal support. The outlet at the upper end of the centrifuge is connected to a first guide rail, which is arc-shaped. The lower end of the first guide rail is connected to a vertical second guide rail, which is fixed to the vertical support.

[0006] Furthermore, the circular tube fixing mechanism includes an upper fastener located above and a lower fastener located below. The lower end of the upper fastener is a concave arc shape and can move up and down; the upper end of the lower fastener is a concave arc shape and the position of the lower fastener is fixed; the upper fastener moves downward and clamps the circular tube together with the lower fastener, and the upper fastener moves upward to release the circular tube.

[0007] Furthermore, the upper fastener is driven by a first cylinder, which is fixed at the lower end of two mounting plates parallel to the second guide rail. The mounting plates are vertically fixed to the vertical bracket on the left and right sides of the second guide rail. A first telescopic rod is connected below the first cylinder, and a first base plate is fixedly connected to the lower end of the first telescopic rod. The upper fastener is connected to the lower end of the first base plate.

[0008] Furthermore, the left and right welding mechanisms are driven by a second cylinder and a third cylinder, respectively. The centerlines of the second and third cylinders are at the same height as the centerline of the circular tube and are fixed horizontally to a vertical support. A second telescopic rod is fixedly connected to the right end of the second cylinder, and a second base plate is fixedly connected to the other end of the second telescopic rod. A left welding head is connected to the other side of the second base plate. A third telescopic rod is fixedly connected to the left end of the third cylinder, and a third base plate is fixedly connected to the other end of the third base plate. A right welding head is connected to the other side of the third base plate. The left and right welding heads are connected to an electric welding circuit. When the electric welding circuit is turned on, the left and right welding heads can weld the circular tube and its internal nut.

[0009] Furthermore, the left and right welding heads are cylindrical, and the ends of the left and right welding heads near the circular tube each have a concave arc with the same diameter as the circular tube.

[0010] Furthermore, the nut positioning mechanism includes a fourth cylinder, which is fixed on a fixed plate behind the vertical support. A fourth telescopic rod is connected to the front of the fourth cylinder, and a fourth base plate is connected to the front of the fourth telescopic rod. A limit post is connected to the front of the fourth base plate. The fourth telescopic rod can extend and retract horizontally under the action of the fourth cylinder, thereby driving the fourth base plate and the limit post connected to it to move back and forth. The fourth base plate and the limit post move forward to send the nut into the designated position inside the round tube.

[0011] Furthermore, a fixing block is provided on the other side of the vertical support corresponding to the fourth base plate. The center of the fixing block and the vertical support corresponding to the center are provided with through holes of the same size. A slider is installed in the through hole. A limit hole is provided in the center of the slider. The limit post can pass through the limit hole to limit the nut.

[0012] Furthermore, the fixing block is provided with a first hinge and a second hinge, which are symmetrical about the horizontal center line of the fixing block. The first upper leaf piece on the first hinge and the second lower leaf piece on the second hinge are fixed to the fixing block by a first screw and a second screw, respectively. The first lower leaf piece and the second upper leaf piece can rotate along the first pivot on the first hinge and the second pivot on the second hinge, respectively. The first pivot and the second pivot are also provided with a first torsion spring and a second torsion spring. Both ends of the first torsion spring and the second torsion spring have protruding straight torsion arms perpendicular to the first pivot and the second pivot. When the first lower leaf piece and the second upper leaf piece rotate forward, the straight torsion arms on the first torsion spring and the second torsion spring exert a backward reset thrust on the first lower leaf piece and the second upper leaf piece. The first lower leaf piece and the second upper leaf piece have circular grooves opposite each other, and the size of the grooves is slightly larger than the outer diameter of the nut.

[0013] This invention achieves the following beneficial effects: The welding device for a nut inside a round tube, the moving nut feeding mechanism, the nut positioning mechanism, and the round tube fixing mechanism are used in combination to position the nut inside the round tube, effectively saving labor, improving operational efficiency, and ensuring high operational safety. Furthermore, because the nut is assembled by machine, precise positioning of the nut is achieved, avoiding contamination of the nut surface and ensuring the accuracy and strength of the welding. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present utility model. Figure 1 .

[0015] Figure 2 This is a schematic diagram of the overall structure of an embodiment of the present utility model. Figure 2 .

[0016] Figure 3 This is an enlarged version of the nut positioning mechanism of this utility model embodiment. Figure 1 .

[0017] Figure 4 This is an enlarged version of the nut positioning mechanism of this utility model embodiment. Figure 2 .

[0018] Explanation of reference numerals in the attached drawings: 1. Support; 101. Vertical support; 102. Horizontal support; 2. Nut feeding mechanism; 201. Centrifuge; 202. First guide rail; 203. Second guide rail; 3. Round tube fixing mechanism; 301. Fixing plate; 302. First cylinder; 303. First telescopic rod; 304. First base plate; 305. First guide rod; 306. Upper fastener; 307. Lower fastener; 308. Round tube fixing base; 309. Round tube limiting component; 4. Left welding mechanism; 401. Second cylinder; 402. Second telescopic rod; 403. Second base plate; 404. Left welding head; 5. Right welding mechanism; 501. Third cylinder. 502. Third telescopic rod; 503. Third base plate; 504. Right welded head; 6. Nut positioning mechanism; 601. Fourth cylinder; 602. Fourth telescopic rod; 603. Fourth base plate; 604. Limiting post; 605. Fixing block; 606. Sliding block; 610. First hinge; 611. First upper page; 612. First lower page; 613. First pivot; 614. First torsion spring; 615. First positioning hole; 616. First screw; 620. Second hinge; 621. Second upper page; 622. Second lower page; 623. Second pivot; 624. Second torsion spring; 625. Second positioning hole; 626. Second screw. Detailed Implementation

[0019] To better understand the purpose, structure, and function of this utility model, a welding device for a round tube with an internal nut is described in further detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described are for illustrative purposes only and are not intended to limit the scope of this utility model. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to this utility model, not the entire structure.

[0020] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or a connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0021] In this invention, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0022] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0023] like Figure 1-2 As shown, the circular tube built-in nut welding device of this utility model includes a bracket 1, which includes a base (not shown in the figure). A vertical bracket 101 is fixed above the base, and a horizontal bracket 102 is fixedly connected to the upper end of the vertical bracket 101. A nut feeding mechanism 2 is fixed above the horizontal bracket 102. The nut feeding mechanism 2 includes a centrifuge 201. A first guide rail 202 is connected to the outlet of the centrifuge 201. The first guide rail 202 is arc-shaped. The nut's movement direction changes from the horizontal direction at the outlet of the centrifuge 201 to the vertical direction after entering the first guide rail 202. A second guide rail 203 is connected to the lower end of the first guide rail 202. The second guide rail 203 is fixed on the vertical bracket 101. The nut moves vertically downward along the inner wall of the second guide rail 203 under the action of gravity.

[0024] A circular tube fixing mechanism 3 is installed on the vertical support 101. The circular tube fixing mechanism 3 includes two fixing plates 301, which are parallel to the second guide rail 203 and are located on the left and right sides of the second guide rail 203, respectively. The fixing plates 301 are vertically fixedly connected to the vertical support 101. A first cylinder 302 is fixedly connected to the lower end of the fixing plate 301. A first telescopic rod 303 is connected below the first cylinder 302. A first base plate 304 is fixedly connected to the lower end of the first telescopic rod 303. An upper fastener 306 is connected to the lower end of the first base plate 304. The lower end of the upper fastener 306 is a concave arc surface. The diameter of the arc is equal to the outer diameter of the circular tube, and the length of the arc is less than or equal to half the circumference.

[0025] A first guide rod 305 is also installed on the first base plate 304. The other end of the first guide rod 305 is fixedly connected to the first cylinder 302. When the first cylinder 302 drives the first telescopic rod 303 to move vertically, the first base plate 304 and the upper fastener 306 move up and down with the first telescopic rod 303. The first guide rod 305 plays a positioning role. Guide rods are provided between the cylinder and the base plate in the following text, which will not be described in detail below.

[0026] A lower fastener 307 is installed below the upper fastener 306. The upper end of the lower fastener 307 is a concave arc surface, and the upper end of the lower fastener 307 also has an inwardly concave arc. The diameter of the arc is equal to the outer diameter of the circular tube, and the length of the arc is less than or equal to half the circumference. The lower end of the lower fastener 307 is fixed above the circular tube fixing base 308. One end of the circular tube fixing base 308 is fixed to the vertical bracket 101, and the other end protrudes beyond the vertical bracket 101. The circular tube fixing base 308 is perpendicular to the vertical bracket 101. A circular tube limiting member 309 is provided at the end of the circular tube fixing base 308 away from the vertical bracket 101. The circular tube limiting member 309 is L-shaped and is connected to the circular tube fixing base 308 by screws or threaded rods. The circular tube limiting member 309 can move on the circular tube fixing base 308 to accommodate circular tubes of different lengths. The horizontal end of the L-shaped circular tube limiting member 309 is on the same horizontal plane as the lowest point of the arc of the lower fastener 307. Holding the circular tube in the middle, the two ends of the tube are respectively located at the lowest point of the arc of the lower fastener 307 and on the circular tube limiting member 309. Under the thrust of the first cylinder 302, the upper fastener 306 moves vertically downwards until the concave arc of the upper fastener 306 coincides with the outer wall of the circular tube. The circular tube is then fixed in position by the clamping of the upper fastener 306 and the lower fastener 307. One end of the circular tube rests tightly against the circular tube limiting member 309, while the other end protrudes beyond the upper fastener 306 and the lower fastener 307, with the protruding length exceeding the thickness of the built-in nut to be welded.

[0027] Left welding mechanism 4 and right welding mechanism 5 are respectively provided on the left and right sides of the lower fastener 307. Left welding mechanism 4 includes a second cylinder 401, which is horizontally fixed to the vertical bracket 101 via a fixing plate 301. A second telescopic rod 402 is fixedly connected to the right end of the second cylinder 401, and a second base plate 403 is fixedly connected to the other end of the second telescopic rod 402. A left welding head 404 is connected to the other side of the second base plate 403, and a welding control circuit is connected to the left welding head 404. The left welding head 404 is cylindrical and on the same horizontal plane as the circular tube. The other end of the left welding head 404 has a concave arc with the same diameter as the circular tube. When the second cylinder 401 pushes the second telescopic rod 402 to extend to the right, the second base plate 403 and the left welding head 404 fixed to the second base plate 403 move to the right under the push of the second telescopic rod 402.

[0028] The right welding mechanism 5 and the left welding mechanism 4 on the right side of the lower fastener 307 are arranged symmetrically with respect to the lower fastener 307. The right welding mechanism 5 is equipped with a third cylinder 501, which is fixed to the fixed plate 301. A third telescopic rod 502 is located on the left side of the third cylinder 501, and the other end of the third telescopic rod 502 is fixedly connected to the third base plate 503. A right welding head 504 is fixedly connected to the left side of the third base plate 503, and a welding control circuit is connected to the right welding head 504. The right welding head 504 is cylindrical and is on the same horizontal plane as the round tube. The other end of the right welding head 504 has a concave arc with the same diameter as the round tube. When the third cylinder 501 pushes the third telescopic rod 502 to extend to the left, the third base plate 503 and the right welding head 504 fixed to the third base plate 503 move to the left under the push of the third telescopic rod 502. The left welding head 404 moves to the right, and the right welding head 504 moves to the left. The two welding heads and the end of the round tube protruding from the upper fastener 306 are on the same horizontal line. The concave arc ends of the two welding heads surround the end of the round tube protruding from the upper fastener 306. The sum of the lengths of the arcs at both ends is less than the outer diameter circumference of the round tube.

[0029] A nut positioning mechanism 6 is provided below the second guide rail 203. The nut positioning mechanism 6 includes, for example, Figure 3 The fourth cylinder 601 shown is fixed to a fixed plate (not shown) behind the vertical bracket 101. A fourth telescopic rod 602 is connected to the front of the fourth cylinder 601, and a fourth base plate 603 is connected to the front of the fourth telescopic rod 602. A limit post 604 is connected to the front of the fourth base plate 603. The fourth telescopic rod 602 can extend and retract horizontally under the action of the fourth cylinder 601, thereby driving the fourth base plate 603 and the limit post 604 connected to it to move back and forth.

[0030] A through hole is provided on the vertical bracket 101 corresponding to the fourth base plate 603, and the size of the through hole is larger than the outer size of the fourth base plate 603. When the fourth telescopic rod 602 moves forward, the limiting post 604 and the fourth base plate 603 pass through the through hole on the vertical bracket 101 in sequence.

[0031] A fixing block 605 is provided on the other side of the vertical support 101 corresponding to the fourth base plate 603. The fixing block 605 is larger than the fourth base plate 603. A hollowed-out slide is provided in the center of the fixing block 605, and a slider 606 is provided in the slide. A positioning hole is provided in the center of the slider 606. The size of the slider 606 is larger than the size of the nut, and the size of its central positioning hole is larger than the outer diameter of the limiting post 604 but smaller than the inner diameter of the nut. When the fourth telescopic rod 602 moves forward, the limiting post 604 and the fourth base plate 603 pass through the through hole on the vertical support 101 in sequence. The limiting post 604 passes through the central positioning hole of the slider 606, and the fourth base plate 603 contacts the slider 606, pushing the slider 606 forward.

[0032] The upper side of the fixing block 605 is connected to the lower end of the second guide rail 203. A first hinge 610 and a second hinge 620 are provided on the fixing block 605, symmetrically arranged along the horizontal center line of the fixing block 605. The first hinge 610 has four first positioning holes 615, symmetrically distributed on the first upper leaf piece 611 and the first lower leaf piece 612. A first screw 616 is installed in the first positioning hole 615 of the first upper leaf piece 611, while no screws are installed in the two first positioning holes 615 on the first lower leaf piece 612, allowing the first lower leaf piece 612 to rotate along the first pivot 613 on the first hinge 610. A first torsion spring 614 is also provided on the first rotating shaft 613. The first torsion spring 614 has protruding straight torsion arms at both ends. The two straight torsion arms are perpendicular to the first rotating shaft 613 and are located on the first upper plate 611 and the first lower plate 612, respectively. When the first lower plate 612 rotates forward along the first rotating shaft 613, the straight torsion arms on its plate exert a backward restoring thrust on it. A circular groove is provided on the first lower plate 612. The size of the groove is slightly larger than the size of the nut and is used to position the nut.

[0033] The second hinge 620 has four second positioning holes 625, symmetrically distributed on the second upper leaf piece 621 and the second lower leaf piece 622. A second screw 626 is installed in the second positioning hole 625 of the second lower leaf piece 622. No screws are installed in the two second positioning holes 625 on the second upper leaf piece 621, allowing the second upper leaf piece 621 to rotate along the second pivot 623 on the second hinge 620. A second torsion spring 624 is also provided on the second pivot 623. The second torsion spring 624 has protruding straight torsion arms at both ends. The two straight torsion arms are perpendicular to the second pivot 623 and are located on the second upper leaf piece 621 and the second lower leaf piece 622, respectively. When the second upper leaf piece 621 rotates forward along the second pivot 623, the straight torsion arms on its leaf piece exert a backward restoring thrust. A circular groove is formed on the second upper leaf piece 621, slightly larger than the size of the nut, for positioning the nut.

[0034] In use, first place the round tube on the lower fastener 307 and the round tube limiting member 309, turn on the switch, the first cylinder 302 pushes the first telescopic rod 303 to move downward, the first base plate 304 and the upper fastener 306 move downward under the action of the first telescopic rod 303 until the upper fastener 306 is in contact with the upper edge of the round tube, and the upper fastener 306 and the lower fastener 307 fix the round tube in the set position.

[0035] Then, a nut is placed in centrifuge 201 and centrifuge 201 is turned on. Under the action of centrifuge 201, the nut moves to the upper end of the first guide rail 202. Under the action of gravity, it slides along the first guide rail 202 into the second guide rail 203 and continues to slide down. When the nut contacts the upper side of the fixing block 605 and continues to descend, the fourth cylinder 601 begins to push the fourth telescopic rod 602 forward. The fourth telescopic rod 602 pushes the fourth base plate 603 and the limiting post 604 forward. The limiting post 604 passes through the through hole of the vertical bracket 101 and the center hole of the slider 606. The fourth base plate 603 contacts the slider 606, pushing the slider 606 and the nut forward together. The slider 606 pushes the first lower page 612 and the second upper page 621 apart. When the first lower page 612 is pushed apart to an angle of 15° with the vertical direction, the nut slides onto the first rotating shaft 613. The nut slides down the inclined surface formed by the first lower leaf plate 612 via the first pivot 613 to the middle of the first hinge 610 and the second hinge 620. The limiting post 604 passes through the through hole of the vertical bracket 101 and the center hole of the slider 606, and continues to pass through the center of the nut. The limiting post 604, together with the circular groove on the second upper leaf plate 621, prevents the nut from falling further, limiting the height of the nut. The fourth telescopic rod 602 continues to push the fourth base plate 603 and the limiting post 604 forward until the limiting post 604 pushes the nut into the circular tube, at which point the fourth telescopic rod 602, the fourth base plate 603, and the limiting post 604 stop moving.

[0036] The second cylinder 401 and the third cylinder 501 simultaneously begin to push the second telescopic rod 402 and the third telescopic rod 502 towards the circular tube. Under the thrust of the second cylinder 401, the second telescopic rod 402 pushes the second base plate 403 and the left welding head 404 to the right until they contact the circular tube; under the thrust of the third cylinder 501, the third telescopic rod 502 pushes the third base plate 503 and the right welding head 504 to the left until they contact the circular tube. The welding power is turned on, and the left welding head 404 and the right welding head 504 simultaneously generate current to the outside of the circular tube, forming a weld around the six edges of the inner wall of the circular tube where it contacts the nut. The nut is then welded and fixed inside the circular tube.

[0037] After welding is completed, the second cylinder 401 and the third cylinder 501 simultaneously retract the second telescopic rod 402 and the third telescopic rod 502, moving the left welding head 404 and the right welding head 504 away from the circular tube. The fourth cylinder 601 drives the fourth retraction rod 604 to retract backward, and the fourth base plate 603 and the limiting post 604 gradually retract back and forth. The first hinge 610 and the second hinge 620 return to their original position under the action of the first torsion spring 614 and the second torsion spring 624. The slider 606 moves backward under the push of the first hinge 610 and the second hinge 620 until the leaves of the first hinge 610 and the second hinge 620 are in the same plane, and the first torsion spring 614 and the second torsion spring 624 are in a relaxed state. The first cylinder 302 drives the first telescopic rod 303 to retract upwards. The upper fastener 306 moves upwards under the action of the first telescopic rod 303, away from the round tube, and removes the round tube from the middle of the round tube from the lower fastener 307 and the round tube limiting member 309, thus obtaining the round tube with the built-in nut welded on.

[0038] This utility model discloses an electric welding device for a nut inside a round tube. The device combines a moving nut feeding mechanism, a nut positioning mechanism, and a round tube fixing mechanism to position the nut inside the round tube, effectively saving labor, improving operational efficiency, and ensuring high operational safety. Furthermore, because the nut is assembled by machine, precise nut positioning is achieved, avoiding contamination of the nut surface and guaranteeing the accuracy and strength of the weld.

[0039] It is understood that this utility model has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of this utility model. Furthermore, under the teachings of this utility model, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of this utility model.

Claims

1. A welding device for a round tube with an internal nut, comprising a bracket (1), the bracket (1) including a base, a vertical bracket (101) fixed above the base, and a horizontal bracket (102) fixedly connected to the upper end of the vertical bracket (101), characterized in that, A nut feeding mechanism (2) is fixed above the horizontal support (102). The lower end of the nut feeding mechanism (2) is connected to the nut positioning mechanism (6). The nut enters the nut positioning mechanism (6) through the nut feeding mechanism (2). A round tube fixing mechanism (3) is set in front of the nut positioning mechanism (6). The nut positioning mechanism (6) can move in the horizontal direction and push the nut to a designated position inside the round tube. A left welding mechanism (4) and a right welding mechanism (5) are set on both sides of the round tube fixing mechanism (3). The left welding mechanism (4) and the right welding mechanism (5) can contact the outer surface of the round tube at the same time and weld the round tube and its internal nut. The nut positioning mechanism (6), the round tube fixing mechanism (3), the left welding mechanism (4) and the right welding mechanism (5) are respectively fixed on the vertical support (101).

2. The welding device for an internal nut in a round tube according to claim 1, characterized in that, The nut feeding mechanism (2) includes a centrifuge (201) mounted on a horizontal support (102). The outlet of the centrifuge (201) is connected to a first guide rail (202), which is arc-shaped. The lower end of the first guide rail (202) is connected to a vertical second guide rail (203), which is fixed on the vertical support (101).

3. The electric welding device for a round tube with an internal nut according to claim 2, characterized in that, The tube fixing mechanism (3) includes an upper fastener (306) located above and a lower fastener (307) located below. The lower end of the upper fastener (306) is a concave arc surface and can move up and down. The upper end of the lower fastener (307) is a concave arc surface and the position of the lower fastener (307) is fixed. The upper fastener (306) moves downward and clamps the tube together with the lower fastener (307). The upper fastener (306) moves upward to release the tube.

4. The electric welding device for a round tube with an internal nut according to claim 3, characterized in that, The upper fastener (306) is driven by the first cylinder (302). The first cylinder (302) is fixed at the lower end of two fixed plates (301) and parallel to the second guide rail (203). The fixed plates (301) are vertically fixed to the vertical bracket (101) on the left and right sides of the second guide rail (203). A first telescopic rod (303) is connected below the first cylinder (302). A first base plate (304) is fixedly connected to the lower end of the first telescopic rod (303). The upper fastener (306) is connected to the lower end of the first base plate (304).

5. The electric welding device for a round tube with an internal nut according to claim 1, characterized in that, The left welding mechanism (4) and the right welding mechanism (5) are driven by the second cylinder (401) and the third cylinder (501) respectively. The center lines of the second cylinder (401) and the third cylinder (501) are on the same horizontal plane as the center line of the circular tube and are fixed to the vertical support (101) in the horizontal direction. The right end of the second cylinder (401) is fixedly connected to the second telescopic rod (402), and the other end of the second telescopic rod (402) is fixedly connected to the second base plate (403). The other side of the cylinder (501) is connected to a left welding head (404); the left end of the third cylinder (501) is fixedly connected to a third telescopic rod (502), the other end of the third telescopic rod (502) is fixedly connected to a third base plate (503), the other side of the third base plate (503) is connected to a right welding head (504), the left welding head (404) and the right welding head (504) are connected to an electric welding circuit, when the electric welding circuit is turned on, the left welding head (404) and the right welding head (504) can weld the round tube and its internal nut.

6. The electric welding device for a round tube with an internal nut according to claim 5, characterized in that, The left welding head (404) and the right welding head (504) both have concave arcs at the ends near the round tube. The diameter of the arc is the same as the outer diameter of the round tube, and the sum of the lengths of the arcs at both ends is less than the outer circumference of the round tube.

7. The electric welding device for a round tube with an internal nut according to claim 1, characterized in that, The nut positioning mechanism (6) includes a fourth cylinder (601), which is fixed on a fixed plate (301) behind the vertical support (101). A fourth telescopic rod (602) is connected to the front of the fourth cylinder (601), and a fourth base plate (603) is connected to the front of the fourth telescopic rod (602). A limit post (604) is connected to the front of the fourth base plate (603). The fourth telescopic rod (602) can extend and retract back and forth under the action of the fourth cylinder (601) to drive the fourth base plate (603) and the limit post (604) connected to it to move back and forth. The fourth base plate (603) and the limit post (604) move forward to send the nut into the designated position inside the round tube.

8. The electric welding device for a round tube with an internal nut according to claim 7, characterized in that, A fixing block (605) is provided on the other side of the vertical support (101) corresponding to the fourth base plate (603). The center of the fixing block (605) and the vertical support (101) corresponding to the center are provided with through holes of the same size. A slider (606) is installed in the through hole. A limit hole is provided in the center of the slider (606). The limit post (604) can pass through the limit hole to limit the nut.

9. The electric welding device for a round tube with an internal nut according to claim 8, characterized in that, The fixing block (605) is provided with a first hinge (610) and a second hinge (620). The first hinge (610) and the second hinge (620) are symmetrical about the horizontal center line of the fixing block (605). The first upper page piece (611) on the first hinge (610) and the second lower page piece (622) on the second hinge (620) are respectively fixed to the fixing block (605) by a first screw (616) and a second screw (626). The first lower page piece (612) and the second upper page piece (621) can rotate along the first pivot (613) on the first hinge (610) and the second pivot (623) on the second hinge (620), respectively. A first torsion spring (614) and a second torsion spring (624) are also provided on the first torsion spring (613) and the second torsion spring (623). Both ends of the first torsion spring (614) and the second torsion spring (624) have protruding straight torsion arms perpendicular to the first torsion spring (613) and the second torsion spring (623). When the first lower page (612) and the second upper page (621) rotate forward, the straight torsion arms on the first torsion spring (614) and the second torsion spring (624) have a backward reset thrust on the first lower page (612) and the second upper page (621). The first lower page (612) and the second upper page (621) have circular grooves opposite each other. The size of the grooves is slightly larger than the outer diameter of the nut.

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