Bent arm welding tool

Abstract

The utility model discloses a bent arm welding tool, belongs to the field of welding auxiliary facilities, and aims to improve the welding efficiency and precision. A base is included; the base is provided with a limiting structure I for supporting and limiting the position of the connecting rod I; the limiting structure II is used for supporting and limiting the position of the upper bent arm; the limiting structure III is used for supporting and limiting the position of the lower bent arm; the limiting structure IV is used for supporting and limiting the position of a connecting shaft on the vehicle door; the limiting structure V is used for supporting and limiting the position of the vehicle door lower connecting shaft; the sixth limiting structure is used for supporting and limiting the second connecting rod; after the first connecting rod, the automobile door upper connecting shaft, the automobile door lower connecting shaft, the upper bent arm, the lower bent arm and the second connecting rod are in place, the relative position relation among the connecting rods meets the requirement of the bent arm assembly. Thus, after all parts forming a bent arm assembly are installed on the bent arm welding tool at a time, construction of all welding seams can be completed at a time, all the welding seams are made to be based on the same welding datum, the welding seam consistency of all the welding seams is guaranteed, and the finished product quality of the bent arm assembly is guaranteed.

Description

Technical Field

[0001] This utility model belongs to the field of welding auxiliary facilities, specifically a curved arm welding fixture. Background Technology

[0002] The middle door arm assembly of a bus is one of the key components of the bus door system. It is mainly used to connect the door and the vehicle body, support the opening and closing movement of the door, and ensure the stability and safety of the door during operation. Figure 1 A passenger vehicle middle door curved arm assembly structure is disclosed, including a lower curved arm 101, an upper curved arm 102, a connecting rod 103, a connecting rod 104, an upper door connecting shaft 106, and a lower door connecting shaft 105; these components are welded into the curved arm assembly 1.

[0003] The connecting rod 103 has connecting shaft ends 103A at both ends, one of which is used to install a support on the vehicle body, and the other is used to install a support under the vehicle body. The lower curved arm 101 and upper curved arm 102 each include an arc segment 101A near the vehicle body, a bent segment 101B near the door, and a straight segment 101C connecting the arc segment 101A and the bent segment 101B. The lower connecting shaft 105 of the door is a stepped shaft, including a lower large shaft segment 105A, a lower middle shaft segment 105B, and a lower small shaft segment 105C. The upper edge of the lower small shaft segment 105C has a flat surface machined along its axial direction. The lower large shaft segment 105A and the bent segment 101B of the lower curved arm 101 are connected by a weld. The upper connecting shaft 106 of the door is a stepped shaft. It includes an upper large shaft section 106A and an upper middle shaft section 106B; the upper large shaft section 106A is connected to the bent section 101B of the upper curved arm 102 by a weld; the second connecting rod 104 is parallel to the first connecting rod 103, one end is connected to the straight section 101C of the upper curved arm 102 by a weld, and the other end is connected to the straight section 101C of the lower curved arm 101 by a weld; the arc section 101A of the lower curved arm 101 is connected to the first connecting rod 103 by a weld, and the arc section 101A of the upper curved arm 102 is connected to the first connecting rod 103 by a weld; a limiting shaft 107 parallel to the first connecting rod 103 is provided in the arc section 101A of the lower curved arm 101, and a connecting pipe 108 is welded in the arc section 101A of the lower curved arm 101, and the limiting shaft 107 is welded to the connecting pipe 108.

[0004] The aforementioned boom assembly has multiple welds. Currently, there are no dedicated welding auxiliary tools to clamp these rod components. During welding, two components are first fixed and welded on the welding workbench, and then the previously welded structure is welded as a whole to the other components until all welds are completed. Throughout the process, the position of the components needs to be frequently adjusted, which not only wastes time but also results in low welding efficiency and difficulty in ensuring accuracy. Utility Model Content

[0005] The purpose of this utility model is to provide a welding fixture for curved arms, which fixes the various components that make up the curved arm assembly, enabling simultaneous welding of the various components and improving welding efficiency and precision.

[0006] The technical solution adopted in this utility model is: a bent-arm welding fixture.

[0007] Including the base;

[0008] The base is equipped with:

[0009] A limiting structure that supports and limits the position of the connecting rod.

[0010] The second limiting structure supports and limits the position of the upper curved arm;

[0011] The third limiting structure supports and limits the position of the lower curved arm;

[0012] The fourth limiting structure supports and limits the position of the connecting shaft on the door;

[0013] Fifth, a limiting structure that lifts up and restricts the position of the lower connecting shaft of the car door;

[0014] And the limiting structure six that supports and restricts the connecting rod two;

[0015] When connecting rod 1 is located at limit structure 1, upper door connecting shaft is located at limit structure 4, lower door connecting shaft is located at limit structure 5, upper curved arm is located at limit structure 2, lower curved arm is located at limit structure 3, and connecting rod 2 is located at limit structure 6, the relative positional relationship between connecting rod 1, upper door connecting shaft, lower door connecting shaft, upper curved arm, lower curved arm, and connecting rod 2 meets the requirements of the curved arm assembly.

[0016] Furthermore, the base includes a horizontal bottom frame, a support beam for installing the first limiting structure, and a support beam for installing the second and third limiting structures; the first support beam is supported on the bottom frame by columns at both ends of its bottom; the second support beam is supported on the bottom frame by columns at both ends of its bottom.

[0017] Furthermore, the limiting structure includes end supports for supporting the connecting shaft head at both ends of the connecting rod, and the end supports are provided with V-shaped grooves for engaging the connecting shaft head, with the end faces of both ends of the connecting rod abutting against the limiting end faces of the two sets of end supports.

[0018] A pressing device is provided on the outer side of the end support along the transverse direction. The pressing head of the pressing device is aligned with the end support above the end support. When the connecting shaft head is supported on the end support, the pressing head of the pressing device presses down on the connecting shaft head.

[0019] Furthermore, two sets of limiting claws are arranged laterally. Each limiting claw includes a mounting base and a claw arm. The mounting base is installed on the base. One end of the claw arm is hinged to the mounting base, and the other end extends upward and bends forward to the top of the connecting rod. One set of claw arms blocks the lower curved arm from the right side of the lower curved arm, and the other set of claw arms blocks the upper curved arm from the left side of the upper curved arm.

[0020] Furthermore, both the second and third limiting structures include a first clamp for locking the straight segment and a second clamp for locking the bent segment.

[0021] Furthermore, the clamp first includes a clamping block first and a clamping plate first; the clamping block first includes a connecting section for connecting with the base and a lifting section for lifting the straight segment, the lifting section includes a bottom lifting plane and a lateral limiting plane, the bottom lifting plane is inclined and the inclination is consistent with the inclination of the straight segment; the clamping plate first is disposed on the opposite side of the lateral limiting plane, and the straight segment is clamped by the clamping plate first and the lateral limiting plane.

[0022] Furthermore, the clamping plate is movably mounted on the clamping block in the longitudinal direction; when the clamping plate moves backward in the longitudinal direction to the limit position, the front end of the clamping plate is located behind the bottom lifting plane in the longitudinal direction.

[0023] Furthermore, the clamping plate is provided with a longitudinally extending strip-shaped hole; a threaded rod is fixed to the side of the clamping block, and the threaded rod passes through the strip-shaped hole and is connected to the adjusting nut.

[0024] Furthermore, the connecting section of the clamping block one is a square tube structure;

[0025] The second limiting structure also includes a bracket for supporting the arc segment of the upper curved arm. The bracket is L-shaped, with the horizontal section of the bracket inserted into the cavity of the connecting section and the top of the vertical section supporting the arc segment.

[0026] Furthermore, the limiting structure three also includes a support column for supporting the limiting shaft. The top of the support column includes an upright plate and a horizontal plate. A pad is provided on the horizontal plate, and the limiting shaft is set in the limiting groove of the pad. An adjustment through hole for installing an adjustment rod is provided on the upright plate. The adjustment rod passes through the adjustment through hole and abuts against the end face of the limiting shaft. A limiting plate adapted to the inclination of the connecting pipe is provided on the inner side of the horizontal plate. The connecting pipe rests against the limiting plate and its bottom end is supported on the horizontal plate.

[0027] Furthermore, the second clamp includes a second clamping block and a second clamping plate. The second clamping block is installed on the base, and the second clamping plate is detachably connected to the second clamping block. The second clamping plate and the second clamping block clamp the bent section relative to each other.

[0028] Furthermore, the limiting structure four includes an L-shaped upper positioning block, on which a transverse through-hole for the upper central shaft section and a slot adapted to the upper large shaft section are provided, the through-hole and the slot being coaxial; a limiting screw is provided on the right side of the upper positioning block, the limiting screw being installed on the base via an ear seat; the stepped surface of the upper positioning block and the limiting screw clamp the upper large shaft section axially;

[0029] A pressing device is provided on the front side of the upper positioning block along the longitudinal direction. When the connecting shaft of the door is located behind the upper positioning block, the pressing head of the pressing device presses down on the upper shaft section.

[0030] Furthermore, the limiting structure five includes a stepped lower positioning block.

[0031] A stepped limiting groove adapted to the lower main shaft section and the lower middle shaft section is provided on the second step surface of the lower positioning block; during operation, the lower main shaft section and the lower middle shaft section are inserted into the limiting groove, and the stepped surface of the limiting groove abuts against the stepped surface between the lower main shaft section and the lower middle shaft section.

[0032] A limiting block is provided on the first step surface of the lower positioning block, and the rear side of the limiting block is in contact with the plane of the lower small shaft segment;

[0033] A pressing device is provided on the front side of the lower positioning block along the longitudinal direction. When the lower connecting shaft of the door is located behind the lower positioning block, the pressing head of the pressing device presses down the lower shaft section.

[0034] Furthermore, the limiting structure six includes two support blocks and a pressing device arranged laterally along the base; when the connecting rod two is located in the groove of the support block, the pressing head of the pressing device presses down on the connecting rod two.

[0035] The beneficial effects of this utility model are as follows: The curved arm welding fixture disclosed in this utility model allows the connecting rod one, upper curved arm, lower curved arm, upper door connecting shaft, lower door connecting shaft, and connecting rod two, which constitute the curved arm assembly, to be limited by corresponding limiting structures. This ensures that after these components are positioned by the curved arm welding fixture, their relative positions meet the requirements of the finished curved arm assembly. Thus, all components constituting the complete curved arm assembly can be installed into the curved arm welding fixture at once, completing the construction of all welds in one go. This ensures that all welds are constructed based on the same welding datum, guaranteeing weld consistency and ensuring the quality of the finished curved arm assembly. Furthermore, the entire process eliminates the need for frequent adjustments to component positions, saving adjustment time. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the curved arm assembly structure;

[0037] Figure 2 This is a schematic diagram of the bent arm welding fixture structure disclosed in this utility model;

[0038] Figure 3 This is a schematic diagram of the fixture structure;

[0039] Figure 4 This is a schematic diagram of the lower positioning block structure;

[0040] Figure 5 This is a schematic diagram of four parts of the limiting structure;

[0041] Figure 6 A structural diagram showing the components of the bend arm assembly positioned using a bend arm welding fixture.

[0042] Figure 7 for Figure 6 Main view;

[0043] Figure 8 for Figure 6 Top view;

[0044] Figure 9 for Figure 6 Left view;

[0045] Figure 10 for Figure 6 Right view.

[0046] In the diagram, the components are: curved arm assembly 1, lower curved arm 101, arc segment 101A, bending segment 101B, straight segment 101C, upper curved arm 102, connecting rod one 103, connecting shaft head 103A, connecting rod two 104, lower connecting shaft of the door 105, lower large shaft segment 105A, lower middle shaft segment 105B, lower small shaft segment 105C, upper connecting shaft of the door 106, upper large shaft segment 106A, upper middle shaft segment 106B, limiting shaft 107, connecting pipe 108, limiting structure one 3, end support 301, limiting claw 302, mounting base 3021, claw arm 3022, limiting structure two 4, clamping block one 401, connecting section 4011, lifting section 4012, and bottom. 4013 Lifting plane, 4014 Lateral limiting plane, 402 Clamping plate 1, 4021 Strip hole, 403 Threaded rod, 404 Adjusting nut, 405 Bracket, 406 Clamping block 2, 407 Clamping plate 2, 5 Limiting structure 3, 5 Support column, 501 Vertical plate, 5011 Horizontal plate, 5012 Adjusting through hole, 5013 Pad, 502 Limiting plate, 503 Limiting structure 4, 6 Upper positioning block, 601 Step surface, 6011 Insertion hole, 6012 Slot, 6013 Limiting screw, 602 Ear seat, 7 Limiting structure 5, 7 Lower positioning block, 7011 Limiting groove, 702 Limiting block, 706 Limiting structure 6, 8 Support block, 801 Pressing device, 9. Detailed Implementation

[0047] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0048] In this utility model, the terms "longitudinal," "lateral," "vertical," "upper," "front," "rear," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the appendix. Figure 2 The orientation or positional relationship shown is for the purpose of describing the present invention only, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0049] Bending arm welding fixtures, such as Figure 2 As shown, it includes a base 2, on which are provided:

[0050] A limiting structure 3 that supports and limits the position of connecting rod 103;

[0051] Limiting structure 24 that supports and limits the position of the upper curved arm 102;

[0052] Limiting structure 35 that supports and limits the position of the lower curved arm 101;

[0053] The limiting structure 46 supports and limits the position of the connecting shaft 106 on the door;

[0054] Limiting structure 57 that supports and restricts the position of the lower connecting shaft 105 of the door;

[0055] And the limiting structure 68 that supports and limits the connecting rod 2104;

[0056] like Figures 6-10 As shown, when connecting rod 103 is located at limiting structure 1 3, upper door connecting shaft 106 is located at limiting structure 4 6, lower door connecting shaft 105 is located at limiting structure 5 7, upper curved arm 102 is located at limiting structure 2 4, lower curved arm 101 is located at limiting structure 3 5, and connecting rod 2 104 is located at limiting structure 6 8, the relative positional relationship between connecting rod 103, upper door connecting shaft 106, lower door connecting shaft 105, upper curved arm 102, lower curved arm 101, and connecting rod 2 104 satisfies the requirements of curved arm assembly 1.

[0057] The boom welding fixture disclosed in this utility model allows the components constituting the boom assembly 1, such as connecting rod 103, upper boom 102, lower boom 101, upper door connecting shaft 106, lower door connecting shaft 105, and connecting rod 104, to be limited by corresponding limiting structures. This ensures that after being positioned by the boom welding fixture, the relative positions of these components meet the requirements of the finished boom assembly 1. Thus, all components constituting the boom assembly 1 can be installed into the welding fixture at once, completing all welds in one go. This ensures that all welds are constructed based on the same welding reference, guaranteeing weld consistency and thus ensuring the quality of the finished boom assembly 1. Furthermore, the entire process eliminates the need for frequent adjustments to component positions, saving adjustment time.

[0058] like Figure 1 As shown, the base 2 includes a horizontal bottom frame 201, a supporting beam 202 for installing the limiting structure 3, and a supporting beam 203 for installing the limiting structure 4 and the limiting structure 5. The supporting beam 202 is supported by columns at both ends of its bottom on the bottom frame 201; the supporting beam 203 is also supported by columns at both ends of its bottom on the bottom frame 201. The frame-like base 2, formed by the beams and columns, has a simple structure, is lightweight, and saves materials.

[0059] The limiting structure 3 includes end supports 301 for supporting the connecting shaft head 103A at both ends of the connecting rod 103. The end supports 301 are provided with V-shaped grooves for engaging the connecting shaft head 103A. The end faces of both ends of the connecting rod 103 abut against the limiting end faces of the two sets of end supports 301.

[0060] A pressing device 9 is provided on the outer side of the end support 301 along the transverse direction. The pressing head of the pressing device 9 is aligned with the end support 301 above the end support 301. When the connecting shaft head 103A is supported on the end support 301, the pressing head of the pressing device 9 presses down on the connecting shaft head 103A.

[0061] The connecting rod 103 is engaged in the V-shaped groove. The V-shaped groove limits the connecting rod 103 along the longitudinal direction, preventing the connecting rod 103 from moving longitudinally.

[0062] Along the transverse direction, the right end face of the end support 301 located on the left end is its limiting end face, and the left end face of the end support 301 located on the right end is its limiting end face. The end faces of both ends of the connecting rod 103 are the end faces that contact the connecting shaft head 103A. The two ends of the connecting rod 103 are locked between the right end face of the end support 301 on the left end and the left end face of the end support 301 on the right end, limiting the connecting rod 103 along the axial direction to prevent the connecting rod 103 from moving in the transverse direction, i.e., the axial direction of the connecting rod 103.

[0063] Once the connecting rod 103 is in place on the end support 301, the connecting shaft head 103A is pressed down by the pressing device 9 to completely lock the connecting rod 103 and prevent it from moving.

[0064] To prevent the connecting rod 103 from bending due to being suspended in the air, a central support block can be set in the middle of the connecting rod 103. The central support block is fixed to the base 2. When in use, the connecting rod 103 is placed directly on the central support block.

[0065] Alternatively, the limiting structure 3 can use a pair of opposing push rods. These push rods can be used to press the connecting rod 103 from both ends along the axial direction of the connecting rod 103 to achieve the desired effect.

[0066] To further limit the movement of connecting rod 103, preferably, two sets of limiting claws 302 are provided laterally. Each limiting claw 302 includes a mounting base 3021 and a claw arm 3022. The mounting base 3021 is mounted on the base 2. One end of the claw arm 3022 is hinged to the mounting base 3021, and the other end extends upward and bends forward above the connecting rod 103. By limiting the connecting rod 103 with two sets of limiting claws 302, the risk of deformation joints caused by welding is further reduced. One set of claw arms 3022 abuts against the lower curved arm 101 from the right side, and the other set abuts against the upper curved arm 102 from the left side. During welding, these claws also provide a certain degree of limitation for the lower and upper curved arms 101, reducing the risk of axial deformation along the connecting rod 103 caused by welding.

[0067] Preferably, both the second limiting structure 4 and the third limiting structure 5 include a first clamp for locking the straight segment 101C and a second clamp for locking the bent segment 101B. The first clamp and the second clamp provide multiple limiting points along the extension direction of the upper bent arm 102 or the lower bent arm 101, thereby improving the stability and reliability of clamping the upper bent arm 102 or the lower bent arm 101.

[0068] Among them, such as Figure 3 As shown, the clamp includes a clamping block 401 and a clamping plate 402. The clamping block 401 includes a connecting section 4011 for connecting to the base 2 and a lifting section 4012 for lifting the straight section 101C. The lifting section 4012 includes a bottom lifting plane 4013 and a lateral limiting plane 4014. The bottom lifting plane 4013 is inclined and its inclination is consistent with the inclination of the straight section 101C. The lifting plane 4013 lifts the straight section 101C from below. The clamping plate 402 is located on the opposite side of the lateral limiting plane 4014, and the clamping plate 402 and the lateral limiting plane 4014 clamp the straight section 101C.

[0069] Clamping plate 402 can be directly attached to clamping block 401 by fastening screws. In use, first, loosen clamping plate 402 and place straight segment 101C on bottom support plane 4013; then, tighten the fastening screws to push clamping plate 402 toward lateral limiting plane 4014 to clamp straight segment 101C.

[0070] To facilitate the insertion of the straight segment 101C while preventing the clamping plate 402 from detaching from the clamping block 401, preferably,

[0071] The clamping plate 402 is movably mounted on the clamping block 401 along the longitudinal direction; when the clamping plate 402 moves backward to the limit position along the longitudinal direction, the front end of the clamping plate 402 is located behind the bottom lifting plane 4013 along the longitudinal direction.

[0072] The movable connection between clamping plate 402 and clamping block 401 can be achieved by a sliding block. In this embodiment, clamping plate 402 is provided with a longitudinally extending strip hole 4021; a threaded rod 403 is fixed to the side of clamping block 401, and the threaded rod 403 passes through the strip hole 4021 and is connected to the adjusting nut 404. This structure is simple and easy to process.

[0073] Preferably, the connecting section 4011 of the clamping block 401 is a square tube structure; the limiting structure 4 further includes a bracket 405 for supporting the arc segment 101A of the upper curved arm 102. The bracket 405 is L-shaped, with its horizontal section inserted into the cavity of the connecting section 4011, and its vertical section supporting the arc segment 101A at its top. The bracket 405 provides additional support for the arc segment 101A, which is more conducive to ensuring the stability of the upper curved arm 102. The bracket 405 is inserted into the connecting section 4011 and then bolted to the base 2, making the structure of the limiting structure 4 more compact.

[0074] In order to simultaneously complete the welding of the limiting shaft 107 and the connecting pipe 108, preferably, the limiting structure 5 further includes a support column 501 for supporting the limiting shaft 107. The top of the support column 501 includes a vertical plate 5011 and a horizontal plate 5012. A pad 502 is provided on the horizontal plate 5012. The limiting shaft 107 is set in the limiting groove of the pad 502. An adjustment through hole 5013 for installing an adjustment rod is provided on the vertical plate 5011. The adjustment rod passes through the adjustment through hole 5013 and abuts against the end face of the limiting shaft 107. A limiting plate 503 adapted to the inclination of the connecting pipe 108 is provided on the inner side of the horizontal plate 5012. The connecting pipe 108 rests on the limiting plate 503 and its bottom end is supported on the horizontal plate 5012.

[0075] The second clamp includes a second clamping block 406 and a second clamping plate 407. The second clamping block 406 is installed on the base 2, and the second clamping plate 407 is detachably connected to the second clamping block 406. The second clamping plate 407 and the second clamping block 406 clamp the bending section 101B respectively.

[0076] A semi-circular clamp can be used as a limiting structure 46 to wrap around and fix the connecting shaft 106 on the door to the base 2. In this embodiment, as shown... Figure 5 As shown, the limiting structure 6 includes an L-shaped upper positioning block 601. The upper positioning block 601 has a transversely extending insertion hole 6012 for the upper central shaft section 106B and a slot 6013 adapted to the upper large shaft section 106A. The insertion hole 6012 and the slot 6013 are coaxial. A limiting screw 602 is provided on the right side of the upper positioning block 601. The limiting screw 602 is installed on the base 2 via an ear seat 603. The stepped surface 6011 of the upper positioning block 601 and the limiting screw 602 clamp the upper large shaft section 106A axially, thus determining the position of the connecting shaft 106 on the door.

[0077] A pressing device 9 is provided longitudinally on the front side of the upper positioning block 601. When the upper connecting shaft 106 of the door is located behind the upper positioning block 601, the pressing head of the pressing device 9 presses down on the upper shaft section 106A. The pressing device 9 can fix the upper connecting shaft 106 of the door and prevent the upper connecting shaft 106 of the door from rotating.

[0078] Similarly, such as Figure 4 As shown, the limiting structure 7 includes a stepped lower positioning block 701. A stepped limiting groove 7011, adapted to the lower main shaft section 105A and the lower middle shaft section 105B, is provided on the second step surface of the lower positioning block 701. During operation, the lower main shaft section 105A and the lower middle shaft section 105B are inserted into the limiting groove 7011, and the stepped surface 6011 of the limiting groove 7011 abuts against the stepped surface between the lower main shaft section 105A and the lower middle shaft section 105B. A limiting block 702 is provided on the first step surface of the lower positioning block 701, and the rear side of the limiting block 702 conforms to the plane of the lower small shaft section 105C. This determines the position of the lower connecting shaft 105 of the door.

[0079] A pressing device 9 is provided on the front side of the lower positioning block 701 along the longitudinal direction. When the lower connecting shaft 105 of the door is located behind the lower positioning block 701, the pressing head of the pressing device 9 presses down the lower shaft section 105A.

[0080] The limiting structure 6 8 includes two support blocks 801 arranged laterally along the base 2 and a pressing device 9; when the connecting rod 2 104 is located in the groove of the support block 801, the pressing head of the pressing device 9 presses down on the connecting rod 2 104. The limiting structure 6 8 can also adopt a clamp structure, etc.

[0081] The pressing device 9 disclosed in this embodiment can be an existing quick clamp or the like.

[0082] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A welding fixture for bent arms, characterized in that: Including the base (2); The base (2) is provided with: A limiting structure (3) that supports and limits the position of connecting rod 1 (103); Limiting structure two (4) that supports and limits the position of the upper curved arm (102); Limiting structure three (5) that supports and limits the position of the lower curved arm (101); Limiting structure four (6) that lifts up and limits the position of the connecting shaft (106) on the door; Limiting structure five (7) that lifts up and limits the position of the lower connecting shaft (105) of the door; And the limiting structure six (8) that supports and limits the connecting rod two (104); When connecting rod 1 (103) is located in limiting structure 1 (3), upper door connecting shaft (106) is located in limiting structure 4 (6), lower door connecting shaft (105) is located in limiting structure 5 (7), upper curved arm (102) is located in limiting structure 2 (4), lower curved arm (101) is located in limiting structure 3 (5), and connecting rod 2 (104) is located in limiting structure 6 (8), the relative positional relationship between connecting rod 1 (103), upper door connecting shaft (106), lower door connecting shaft (105), upper curved arm (102), lower curved arm (101) and connecting rod 2 (104) satisfies the requirements of curved arm assembly (1).

2. The welding fixture for bent arms as described in claim 1, characterized in that: The limiting structure 1 (3) includes end supports (301) for supporting the connecting shaft head (103A) at both ends of the connecting rod 1 (103). The end supports (301) are provided with V-shaped grooves for engaging the connecting shaft head (103A). The end faces of both ends of the connecting rod 1 (103) abut against the limiting end faces of the two sets of end supports (301). A pressing device (9) is provided on the outer side of the end support (301) along the transverse direction. The pressing head of the pressing device (9) is aligned with the end support (301) above the end support (301). When the connecting shaft head (103A) is supported on the end support (301), the pressing head of the pressing device (9) presses down on the connecting shaft head (103A).

3. The bending arm welding fixture as described in claim 2, characterized in that: Two sets of limiting claws (302) are arranged in the horizontal direction. Each limiting claw (302) includes a mounting base (3021) and a claw arm (3022). The mounting base (3021) is installed on the base (2). One end of the claw arm (3022) is hinged to the mounting base (3021), and the other end extends upward and bends forward to the top of the connecting rod (103). One set of the claw arms (3022) abuts against the lower curved arm (101) from the right side, and the other set of claw arms (3022) abuts against the upper curved arm (102) from the left side.

4. The bending arm welding fixture as described in any one of claims 1-3, characterized in that: Both the second limiting structure (4) and the third limiting structure (5) include a clamp one for locking the straight section (101C) and a clamp two for locking the bent section (101B).

5. The bending arm welding fixture as described in claim 4, characterized in that: The clamp includes a clamping block (401) and a clamping plate (402); the clamping block (401) includes a connecting section (4011) for connecting with the base (2) and a lifting section (4012) for lifting the straight section (101C); the lifting section (4012) includes a bottom lifting plane (4013) and a lateral limiting plane (4014); the bottom lifting plane (4013) is inclined and the inclination is consistent with the inclination of the straight section (101C); the clamping plate (402) is located on the opposite side of the lateral limiting plane (4014), and the straight section (101C) is clamped by the clamping plate (402) and the lateral limiting plane (4014). The second clamp includes a second clamping block (406) and a second clamping plate (407). The second clamping block (406) is installed on the base (2), and the second clamping plate (407) is detachably connected to the second clamping block (406). The second clamping plate (407) and the second clamping block (406) clamp the bent section (101B) respectively.

6. The welding fixture for bent arms as described in claim 5, characterized in that: The clamping plate (402) is movably mounted on the clamping block (401) in the longitudinal direction; when the clamping plate (402) moves backward to the limit position in the longitudinal direction, the front end of the clamping plate (402) is located behind the bottom lifting plane (4013) in the longitudinal direction; the clamping plate (402) is provided with a longitudinally extending strip hole (4021); a threaded rod (403) is fixed on the side of the clamping block (401), and the threaded rod (403) passes through the strip hole (4021) and is connected to the adjusting nut (404).

7. The welding fixture for bent arms as described in claim 5, characterized in that: The connecting section (4011) of the clamping block (401) is a square tube structure; The second limiting structure (4) also includes a bracket (405) for supporting the arc segment (101A) of the upper curved arm (102). The bracket (405) is L-shaped, with the horizontal section of the bracket (405) inserted into the cavity of the connecting section (4011), and the top of the vertical section supporting the arc segment (101A).

8. The bending arm welding fixture as described in any one of claims 1-3, characterized in that: The limiting structure three (5) also includes a support column (501) supporting the limiting shaft (107). The top of the support column (501) includes a vertical plate (5011) and a horizontal plate (5012). A pad (502) is provided on the horizontal plate (5012). The limiting shaft (107) is located in the limiting groove of the pad (502). An adjustment through hole (5013) for installing an adjustment rod is provided on the vertical plate (5011). The adjustment rod passes through the adjustment through hole (5013) and abuts against the end face of the limiting shaft (107). A limiting plate (503) adapted to the inclination of the connecting pipe (108) is provided on the inner side of the horizontal plate (5012). The connecting pipe (108) rests on the limiting plate (503) and its bottom end is supported on the horizontal plate (5012).

9. The bending arm welding fixture as described in any one of claims 1-3, characterized in that: The limiting structure four (6) includes an L-shaped upper positioning block (601), on which a transverse through-hole (6012) for the upper central shaft section (106B) and a slot (6013) adapted to the upper large shaft section (106A) are provided, the through-hole (6012) and the slot (6013) being coaxial; a limiting screw (602) is provided on the right side of the upper positioning block (601), the limiting screw (602) being installed on the base (2) via an ear seat (603); the stepped surface (6011) of the upper positioning block (601) and the limiting screw (602) clamp the upper large shaft section (106A) axially; A pressing device (9) is provided on the front side of the upper positioning block (601) along the longitudinal direction. When the upper connecting shaft (106) of the door is located behind the upper positioning block (601), the pressing head of the pressing device (9) presses down on the upper shaft section (106A).

10. The bending arm welding fixture according to any one of claims 1-3, characterized in that: The limiting structure five (7) includes a stepped lower positioning block (701), A stepped limiting groove (7011) adapted to the lower large shaft section (105A) and the lower middle shaft section (105B) is provided on the second step surface of the lower positioning block (701); during operation, the lower large shaft section (105A) and the lower middle shaft section (105B) are inserted into the limiting groove (7011), and the stepped surface (6011) of the limiting groove (7011) abuts against the stepped surface between the lower large shaft section (105A) and the lower middle shaft section (105B); A limiting block (702) is provided on the first step surface of the lower positioning block (701), and the rear side of the limiting block (702) is in contact with the plane of the lower small shaft segment (105C). A pressing device (9) is provided on the front side of the lower positioning block (701) along the longitudinal direction. When the lower connecting shaft (105) of the door is located behind the lower positioning block (701), the pressing head of the pressing device (9) presses down the lower shaft section (105A).

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