A welding tool system for a trailer hitch cross member

Abstract

The application relates to the field of welding tooling, in particular to a trailer hook cross beam welding tooling system which comprises a first welding tooling and second welding tooling, the first welding tooling is used for temporarily fixing the end connecting plate and the end reinforcing plate in an S1 step, the S1 step is welding and fixing the end reinforcing plate to the end connecting plate, the second welding tooling is used for temporarily fixing the cross beam body, the end connecting plate, the end reinforcing plate and the middle connecting plate in an S2 step, the S2 step is welding and fixing the cross beam body to the end connecting plate and welding and fixing the middle connecting plate to the cross beam body. The application has the effect of reducing the thermal deformation of the trailer cross beam caused by welding.

Description

Technical Field

[0001] This application relates to the field of welding fixtures, and in particular to a welding fixture system for a trailer hook crossbeam. Background Technology

[0002] The trailer hitch crossbeam assembly is a load-bearing structure fixed to the rear of the vehicle's underside, used to mount trailer hitches and provide connection functions such as rescue towing, towing caravans, or cargo trailers. With the increasing demand for outdoor equipment and towing capabilities from new energy vehicles, this assembly, as a key carrier for force transmission and distribution, directly impacts the safety of vehicle rescue and towing missions due to its structural reliability.

[0003] In existing related technologies, the production process of trailer hook crossbeams involves the assembly and welding of multiple metal plates. After each plate is positioned manually or with auxiliary fixtures, it is welded along the joint edge one by one, so that the dispersed plates are fused into an integral crossbeam structure.

[0004] Regarding the aforementioned technologies, when the thickness of the welded plate increases to over 10 mm, the heat accumulation effect in the welding area is significantly enhanced. Under high heat input during welding, the component undergoes intense local thermal cycling, leading to uneven thermal stress within the component. This stress is gradually released during natural cooling, causing irregular thermal contraction deformation of the disengaged beam, resulting in a drift in the relative position of the assembly positioning holes after welding. Application content

[0005] To reduce thermal deformation of trailer crossbeams caused by welding, this application provides a welding fixture system for trailer hook crossbeams.

[0006] The welding fixture system for a trailer hook crossbeam provided in this application adopts the following technical solution: A welding fixture system for a trailer hook crossbeam is provided for welding and assembling a trailer hook crossbeam. The trailer hook crossbeam includes a crossbeam body, end connecting plates, and a middle connecting plate. The end connecting plates are welded and fixed to the ends of the crossbeam body. The end connecting plates are L-shaped and bent. An end stiffening plate is welded and fixed to the inner side of the bend of the end connecting plates. An end positioning hole is provided through the end connecting plates. The middle connecting plate is welded and fixed to the middle of the crossbeam body. A middle positioning hole is provided through the middle connecting plate. The crossbeam body has a crossbeam positioning hole located between the middle connecting plate and the end connecting plate. The welding fixture system for the trailer hook crossbeam includes a first welding fixture and a second welding fixture. The first welding fixture is used to temporarily fix the end connecting plate and the end stiffening plate in step S1, wherein step S1 involves welding and fixing the end stiffening plate to the end connecting plate. The second welding fixture is used to temporarily fix the crossbeam body, the end connecting plate, the end stiffening plate, and the middle connecting plate in step S2, wherein step S2 involves welding and fixing the crossbeam body to the end connecting plate and welding and fixing the middle connecting plate to the crossbeam body.

[0007] By adopting the above technical solution, the positioning and clamping of the first and second welding fixtures allow the end connecting plate, the middle connecting plate, and the crossbeam body to be precisely assembled before welding. This results in the assembled trailer hook crossbeam forming a stable installation platform, facilitating the even distribution and transmission of towing force along the crossbeam body to the vehicle's longitudinal beams, reducing structural damage caused by single-point stress. Furthermore, by breaking down the welding process into steps S1 and S2, the first welding fixture temporarily fixes the end connecting plate and end stiffening plate in step S1, while the second welding fixture temporarily fixes the crossbeam body, end connecting plate, end stiffening plate, and middle connecting plate in step S2. This disperses the heat input from a single welding operation, reducing the accumulation of thermal deformation in the plates caused by concentrated heat. Furthermore, the first and second welding fixtures continue to keep the plates relatively fixed after welding, allowing the workpiece to cool naturally to room temperature under constrained conditions before removal. This helps to suppress hole drift caused by the release of residual welding stress during the cooling process, thereby helping to maintain the positional accuracy of the end positioning holes, the middle positioning holes, and the crossbeam positioning holes, so that the trailer hook crossbeam can be smoothly connected and installed with the vehicle longitudinal beam and other compatible components.

[0008] Optionally, the first welding fixture includes a first fixture frame, a first end plate assembly, a second end plate assembly, and a first stiffening plate assembly; The first end plate assembly includes a first frame, a first cylinder, and a first gripper. The first frame is mounted on a first tooling frame, the first cylinder is mounted on the first frame, and the first cylinder causes the end connecting plate to abut against the first frame via the first gripper. The second end plate assembly includes a second frame, a third cylinder, a second clamp, and a second gripper. The second frame is mounted on the first tooling frame. The third cylinder is mounted on the second frame. The third cylinder has a first positioning post vertically mounted on it. The third cylinder is used to vertically insert the first positioning post into the end positioning hole. The second cylinder is mounted on the first tooling frame. The second cylinder uses the second clamp to make the end connecting plate abut against the second frame. The first stiffening plate assembly includes a first translation slide, a first slide cylinder, a stiffening positioning plate, a first clamping plate, and a first clamping cylinder. The first translation slide is horizontally slidably fitted to the first tooling frame. The first slide cylinder is used to make the first translation slide horizontally approach or move away from the end stiffening plate. The stiffening positioning plate is installed on the first tooling frame. The first clamping plate is horizontally slidably fitted to the first translation slide. The first clamping cylinder makes the end stiffening plate abut against the stiffening positioning plate through the first clamping plate.

[0009] By adopting the above technical solution, the first end plate assembly uses a first cylinder to drive the first gripper to make the end connecting plate abut against the first frame. The second end plate assembly uses a third cylinder to drive the first positioning post to vertically insert into the end positioning hole and a second cylinder to drive the second gripper to make the end connecting plate abut against the second frame, thereby achieving double clamping and hole centering of the end connecting plate, which helps the end connecting plate maintain a stable and accurate position in step S1. At the same time, the first stiffening plate assembly uses a first slide cylinder to drive the first translation slide to move horizontally to the vicinity of the end stiffening plate, and uses a first clamping cylinder to drive the first clamping plate to abut against the stiffening positioning plate, which facilitates the rapid clamping of the end stiffening plate and makes the relative welding position of the end stiffening plate and the end connecting plate more accurate, thereby helping to reduce the occurrence of welding deformation caused by clamping deviation.

[0010] Optionally, the end of the first gripper is rotatably engaged with the first cylinder, and a first connecting rod is provided between the middle of the first gripper and the first frame, with the two ends of the first connecting rod rotatably engaged with the first gripper and the first frame, respectively. The end of the second gripper is rotatably engaged with the second cylinder, and a second connecting rod is provided between the middle of the second gripper and the second frame. The two ends of the second connecting rod are rotatably engaged with the second gripper and the second frame, respectively.

[0011] By adopting the above technical solution, the end of the first gripper is rotatably engaged with the first cylinder, and the middle of the first gripper is hinged to the first frame via a first connecting rod. This allows the linear extension and retraction of the first cylinder to be converted into a swinging clamping action of the first gripper, thereby enhancing the clamping stability and positioning accuracy of the first gripper on the end connecting plate. Simultaneously, the end of the second gripper is rotatably engaged with the second cylinder, and the middle of the second gripper is hinged to the second frame via a second connecting rod. This allows the linear extension and retraction of the second cylinder to be converted into a swinging clamping action of the second gripper, further improving the fixing reliability of the end connecting plate and reducing the occurrence of positional displacement of the end connecting plate due to loosening during welding.

[0012] Optionally, the end connecting plate is provided with two end stiffening plates, and the two end stiffening plates are arranged in parallel. There are two first clamping plates, and the two first clamping plates are respectively located on both sides of the stiffening positioning plate. The first translation slide is equipped with a first positioning block, which is located between the two first clamping plates. The two ends of the first clamping cylinder are respectively horizontally installed on the two first clamping plates. In step S1, the two end stiffening plates are respectively located in the gap between the two first clamping plates and the stiffening positioning plate.

[0013] By adopting the above technical solution, the two end stiffening plates are arranged in parallel, and the two first clamping plates are respectively located on both sides of the stiffening positioning plate. The two ends of the first clamping cylinder are horizontally installed on the two first clamping plates, so that the first clamping cylinder can synchronously drive the two first clamping plates to move towards each other, thereby pressing the two end stiffening plates simultaneously against both sides of the stiffening positioning plate, which is beneficial to achieve synchronous positioning and clamping of the two end stiffening plates. At the same time, the first translation slide is equipped with a first positioning block, which is located between the two first clamping plates, so that the interval and position of the two end stiffening plates can be precisely defined, which is beneficial to maintain the relative positional consistency of the two end stiffening plates and the end connecting plate during welding, and reduce the occurrence of welding deformation caused by the positional deviation of the stiffening plates. Meanwhile, by setting two first clamping plates and driving them synchronously by a single first clamping cylinder, the overall structure of the first stiffening plate assembly becomes more compact, which facilitates the first slide cylinder to drive the first clamping plate to move horizontally through the first translation slide. This helps to further improve the clamping efficiency and ease of operation of the first welding fixture in step S1 and reduce the occurrence of positioning error accumulation caused by multiple clamping adjustments.

[0014] Optionally, the reinforcing positioning plate is equipped with a first limiting plate and a second limiting plate. In step S1, the first limiting plate abuts vertically downward against the end reinforcing plate, and the second limiting plate abuts horizontally against the end reinforcing plate towards the first frame.

[0015] By adopting the above technical solution, in step S1, the first limiting plate abuts vertically downward against the end stiffening plate, and the second limiting plate abuts horizontally against the end stiffening plate towards the first frame. This further constrains the vertical warping and horizontal displacement of the end stiffening plate, which is already clamped and fixed by the first clamping plate. This helps to reduce the occurrence of positional displacement of the end stiffening plate due to the release of thermal stress during the welding process, making the welding relative position of the end stiffening plate and the end connecting plate more accurate. This helps to ensure the consistency of the component size formed in step S1 and provides a good positioning basis for the subsequent assembly and welding in step S2.

[0016] Optionally, one of the first clamping plates is rotatably coupled to a first handle, and the other first clamping plate is rotatably coupled to a third link, the third link being rotatably coupled to the middle of the first handle.

[0017] By adopting the above technical solution, in step S1, after the first clamping cylinder drives the two first clamping plates to clamp the end stiffening plate, the operator can move the first handle to further tighten the two first clamping plates through the third linkage, thereby realizing the manual locking of the two first clamping plates. This helps to reduce the occurrence of loosening or displacement of the end stiffening plate due to gas source fluctuations or the attenuation of clamping force of the first clamping cylinder during the welding process, so that the end stiffening plate remains firmly clamped throughout the welding process, thereby helping to ensure the welding position accuracy of the end stiffening plate and the end connecting plate.

[0018] Optionally, the second welding fixture includes a second fixture frame, a third end plate assembly, a crossbeam assembly, and a middle assembly; The third end plate assembly includes an end plate placement platform, a fourth cylinder, a third gripper, a third frame, and a fifth cylinder. The end plate placement platform is mounted on the second tooling frame. The fourth cylinder is vertically mounted on the second tooling frame. The third gripper is mounted on the fourth cylinder. The fourth cylinder uses the third gripper to make the end connecting plate abut against the third frame. The third gripper can abut against the two inner bends of the end connecting plate and make the end connecting plate abut against the end plate placement platform. The third frame is mounted on the second tooling frame. The fifth cylinder is vertically mounted on the third frame. The fifth cylinder is equipped with a second positioning post. The fifth cylinder is used to make the second positioning post vertically inserted into the end positioning hole. The crossbeam assembly includes a crossbeam positioning seat, a sixth cylinder, a seventh cylinder, a fourth clamping jaw, an eighth cylinder, and a fifth clamping jaw. The crossbeam positioning seat is mounted on the second tooling frame. The sixth cylinder is vertically mounted on the crossbeam positioning seat and has a third positioning post. The sixth cylinder is used to vertically insert the third positioning post into the crossbeam positioning hole. The seventh cylinder is vertically mounted on the second tooling frame and has the fourth clamping jaw mounted on the seventh cylinder. The seventh cylinder uses the fourth clamping jaw to make the crossbeam body abut downward against the crossbeam positioning seat. The eighth cylinder is horizontally mounted on the second tooling frame and has the fifth clamping jaw mounted on the eighth cylinder. The eighth cylinder uses the fifth clamping jaw to make the crossbeam body abut horizontally against the crossbeam positioning seat. The central component includes a second translation slide, a second slide cylinder, a connecting positioning plate, a second clamping plate, and a second clamping cylinder. The second translation slide is horizontally slidably fitted to the second tooling frame. The second slide cylinder is used to move the second translation slide horizontally closer to or further away from the central connecting plate. The connecting positioning plate is installed on the second tooling frame. The second clamping plate is horizontally slidably fitted to the second translation slide. The second clamping plate is equipped with a fourth positioning post. The second clamping cylinder uses the second clamping plate to make the central connecting plate abut against the connecting positioning plate. When the second clamping plate abuts against the central connecting plate, the fourth positioning post is horizontally inserted into the central positioning hole.

[0019] By adopting the above technical solution, the third end plate assembly uses the fourth cylinder to drive the third clamping jaws to simultaneously abut against the two inner bends of the end connecting plate, thus pressing the end connecting plate between the third frame and the end plate placement platform. The fifth cylinder drives the second positioning pin to insert into the end positioning hole, thereby achieving multi-point clamping and hole centering of the end connecting plate, which helps to suppress the deviation of the end connecting plate during welding. Simultaneously, the crossbeam assembly uses the sixth cylinder and the third positioning pin to position the crossbeam positioning hole, and the seventh cylinder and the fourth clamping jaws to vertically press the crossbeam body, and the eighth cylinder and the fifth clamping jaws to horizontally press the crossbeam body, thus forming a four-way limit on the crossbeam positioning seat, which helps to maintain the relative angle between the crossbeam body and the end connecting plate. Furthermore, the middle assembly uses the second slide cylinder to drive the second translation slide to move to the middle connecting plate, and the second clamping cylinder pushes the second clamping plate to press the middle connecting plate against the connecting positioning plate. Simultaneously, the fourth positioning pin is inserted into the central positioning hole, thus completing the clamping and positioning simultaneously, which helps reduce the clamping deviation of the central connecting plate. Therefore, through the above-mentioned multi-point, multi-directional joint positioning and clamping, the main components of the trailer hook beam are precisely constrained in step S2, thereby suppressing the relative displacement of the components caused by welding heat input. This helps reduce the occurrence of positional deviations of the positioning holes after welding, and facilitates the subsequent precise assembly of the trailer hook beam with the vehicle frame.

[0020] Optionally, the third gripper has an inclined portion and a vertical portion. The inclined portion is obliquely oriented toward one of the inner bends of the end connecting plate, and the vertical portion is vertically oriented toward the other inner bend of the end connecting plate.

[0021] By adopting the above technical solution, the third gripper is provided with an inclined part and a vertical part. When the fourth cylinder drives the third gripper, the inclined part can obliquely abut against one of the inner sides of the bend of the end connecting plate, and the vertical part can vertically abut against the other inner side of the bend of the end connecting plate. This allows clamping force to be applied to the end connecting plate from two different directions simultaneously, thereby enhancing the contact adaptability between the third gripper and the L-shaped bend of the end connecting plate. This makes the end connecting plate more evenly pressed against the third frame and the end plate placement platform, which helps to reduce the occurrence of warping or positional displacement of the end connecting plate due to the single direction of clamping force during the welding process in step S2. This further ensures the positional accuracy of the end positioning hole during the welding process, facilitating the smooth installation of the trailer hook crossbeam with the matching frame after welding.

[0022] Optionally, there are two central connecting plates arranged in parallel, two second clamping plates, a second positioning block installed on the second translation slide, the second positioning block being located between the two second clamping plates, the two second clamping plates being located on both sides of the connecting positioning plate, and the two ends of the second clamping cylinder being horizontally installed on the two second clamping plates. In step S2, the two central connecting plates are located in the gaps between the two second clamping plates and the connecting positioning plate.

[0023] By adopting the above technical solution, the two central connecting plates are arranged in parallel, and the two second clamping plates are respectively located on both sides of the connecting positioning plate. The two ends of the second clamping cylinder are horizontally mounted on the two second clamping plates, enabling the second clamping cylinder to synchronously drive the two second clamping plates to move towards each other. This simultaneously presses the two central connecting plates against both sides of the connecting positioning plate, facilitating synchronous positioning and clamping of the two central connecting plates. This results in more precise welding relative positions between the two central connecting plates and the crossbeam body. Simultaneously, the second translation slide is equipped with a second positioning block located between the two second clamping plates. This allows for precise definition of the interval and position of the two central connecting plates, helping to maintain the relative positional consistency between the two central connecting plates and the crossbeam body during welding and reducing welding deformation caused by positional deviations of the central connecting plates.

[0024] Optionally, one of the second clamping plates is rotatably coupled to a second handle, and the other second clamping plate is rotatably coupled to a fourth link, the fourth link being rotatably coupled to the middle of the second handle.

[0025] By adopting the above technical solution, after the second clamping cylinder drives the two second clamping plates to clamp the middle connecting plate, the operator can pull the second handle to generate a further tightening displacement of the two second clamping plates through the fourth linkage, thereby realizing the manual locking of the two second clamping plates. This helps to reduce the occurrence of loosening or displacement of the middle connecting plate due to gas source fluctuations or the attenuation of clamping force of the second clamping cylinder during the welding process, so that the middle connecting plate remains firmly clamped throughout the welding process, thus helping to ensure the welding position accuracy of the middle connecting plate and the crossbeam body.

[0026] In summary, this application includes at least one of the following beneficial technical effects: By utilizing the positioning and clamping of the first and second welding fixtures, the end connecting plates, the middle connecting plates, and the crossbeam body can be precisely assembled before welding. This allows the assembled trailer hook crossbeam to form a stable installation platform, facilitating the even distribution and transmission of towing force along the crossbeam body to the vehicle's longitudinal beams, reducing structural damage caused by single-point stress. Simultaneously, by breaking down the welding process into steps S1 and S2, the first welding fixture temporarily fixes the end connecting plates and end stiffening plates in step S1, while the second welding fixture temporarily fixes the crossbeam body, end connecting plates, end stiffening plates, and middle connecting plates in step S2. This disperses the heat input of a single welding operation, thus reducing the accumulation of thermal deformation in the plates caused by concentrated heat. Furthermore, the first and second welding fixtures continue to keep the plates relatively fixed after welding, allowing the workpiece to cool naturally to room temperature under constrained conditions before removal. This helps to suppress hole drift caused by the release of residual welding stress during the cooling process, thereby helping to maintain the positional accuracy of the end positioning holes, the middle positioning holes, and the crossbeam positioning holes, so that the trailer hook crossbeam can be smoothly connected and installed with the vehicle longitudinal beam and other compatible components. Attached Figure Description

[0027] Figure 1 This is an overall view of the trailer hook crossbeam of Embodiment 1 of this application.

[0028] Figure 2 This is an overall view of the first welding fixture in Embodiment 2 of this application.

[0029] Figure 3 This is an overall view of the first endplate assembly in Embodiment 2 of this application.

[0030] Figure 4 This is an overall view of the second endplate assembly in Embodiment 2 of this application.

[0031] Figure 5 This is an overall view of the first stiffening plate assembly in Embodiment 2 of this application.

[0032] Figure 6This is a diagram of the reinforced positioning plate and the first positioning block in Embodiment 2 of this application.

[0033] Figure 7 This is an overall view of the second welding fixture in Embodiment 3 of this application.

[0034] Figure 8 This is an overall diagram of the third endplate assembly in Embodiment 3 of this application.

[0035] Figure 9 This is an overall view of the beam assembly in Embodiment 3 of this application.

[0036] Figure 10 This is an overall view of the components in Embodiment 3 of this application.

[0037] Figure 11 This is an overall view of the second clamping plate in Embodiment 3 of this application.

[0038] Explanation of reference numerals in the attached drawings: 11. Crossbeam body; 111. Crossbeam positioning hole; 12. End connecting plate; 121. End positioning hole; 122. End stiffening plate; 13. Middle connecting plate; 131. Middle positioning hole; 2. First end plate assembly; 21. First frame; 22. First cylinder; 23. First gripper; 231. First connecting rod; 3. Second end plate assembly; 31. Second frame; 32. Third cylinder; 321. First positioning post; 33. Second cylinder; 34. Second gripper; 341. Second connecting rod; 4. First stiffening plate assembly; 41. First translation slide; 411. First positioning block; 42. First slide cylinder; 43. Stiffening positioning plate; 431. First limiting plate; 432. Second limiting plate; 44. First clamping plate; 441. 1. Handle; 442. Third link; 45. First clamping cylinder; 5. Third end plate assembly; 51. End plate placement platform; 52. Fourth cylinder; 53. Third gripper; 531. Inclined part; 532. Vertical part; 54. Third frame; 55. Fifth cylinder; 551. Second positioning post; 6. Crossbeam assembly; 61. Crossbeam positioning seat; 62. Sixth cylinder; 621. Third positioning post; 63. Seventh cylinder; 64. Fourth gripper; 65. Eighth cylinder; 66. Fifth gripper; 7. Middle assembly; 71. Second translation slide; 711. Second positioning block; 72. Second slide cylinder; 73. Connecting positioning plate; 74. Second clamping plate; 741. Fourth positioning post; 742. Second handle; 743. Fourth link; 75. Second clamping cylinder. Detailed Implementation

[0039] The following is in conjunction with the appendix Figure 1-11 This application will be described in further detail.

[0040] Example 1: This application discloses a trailer hitch crossbeam, which includes a crossbeam body 11, an end connecting plate 12, and a middle connecting plate 13. (Refer to...) Figure 1 The crossbeam body 11 is in the shape of a quadrangular prism, and a crossbeam positioning hole 111 is formed through the crossbeam body 11. The crossbeam positioning hole 111 is located between the middle connecting plate 13 and the end connecting plate 12. The crossbeam positioning hole 111 can be used for vehicle assembly and for positioning posts in conjunction with welding fixtures, so as to constrain the position of the crossbeam body 11 during the welding process, so that the crossbeam body 11 maintains a stable clamping state and reduces the positional displacement of the crossbeam body 11 caused by welding stress.

[0041] Two end connecting plates 12 are provided, respectively located at both ends of the crossbeam body 11. The end connecting plates 12 are L-shaped bends, and the L-shape gives each end connecting plate 12 two obtuse-angled surfaces. This allows the end connecting plate 12 to be fixedly connected to the crossbeam body 11 on one surface, while the trailer hook crossbeam is assembled to the vehicle on the other surface. The end connecting plates 12 have four rectangularly distributed end positioning holes 121. These holes 121 can be used with positioning posts of welding fixtures, facilitating hole centering of the end connecting plates 12 during welding, thereby helping to maintain the positional accuracy of the end connecting plates 12 during the welding process.

[0042] Two triangular end stiffening plates 122 are welded and fixed to the inner side of the bend of the end connecting plate 12, and the two end stiffening plates 122 are arranged in parallel to enhance the structural rigidity of the bending area of ​​the end connecting plate 12. This ensures that the stress is evenly distributed at the bend when the drag force is transmitted, thereby reducing stress concentration and structural damage. In addition, the end stiffening plates 122 provide a clamping contact surface for the welding fixture, facilitating the welding fixture to firmly clamp the end connecting plate 12.

[0043] Two central connecting plates 13 are provided, and both central connecting plates 13 are welded and fixed to the central area of ​​the crossbeam body 11. Several central positioning holes 131 are provided through the central connecting plates 13. The central positioning holes 131 facilitate the installation of the trailer hook crossbeam with the trailer hook and also facilitate the positioning of the positioning post of the welding fixture. In the welding fixture, the central connecting plates 13 are accurately positioned, which helps to ensure the welding relative position accuracy between the central connecting plates 13 and the crossbeam body 11. This allows the welded trailer hook crossbeam to be smoothly connected and installed with the vehicle chassis and other compatible components through the central connecting plates 13.

[0044] Example 2: This application discloses a welding fixture system for a trailer hook crossbeam, used for welding and assembling the trailer hook crossbeam described in Example 1. (Refer to...) Figure 2The welding fixture system for the trailer hook crossbeam includes a first welding fixture, which is used to weld and fix the end stiffening plate 122 to the end connecting plate 12. The first welding fixture includes a first fixture frame, a first end plate assembly 2, a second end plate assembly 3, and a first stiffening plate assembly 4. The first end plate assembly 2, the second end plate assembly 3, and the first stiffening plate assembly 4 are all installed on the first fixture frame, thereby providing a stable installation reference for each component and helping to ensure the accuracy and reliability of the clamping action.

[0045] Reference Figure 3 The first end plate assembly 2 includes a first frame 21, a first cylinder 22, and a first gripper 23. The first frame 21 is fixedly installed on the first tooling frame and is inclined to provide support for the end connecting plate 12 to be welded and fixed to the surface of the crossbeam body 11. The first cylinder 22 is fixedly installed on the first frame 21. The end of the first gripper 23 is rotatably engaged with the piston rod of the first cylinder 22. A first connecting rod 231 is provided between the middle of the first gripper 23 and the first frame 21. The two ends of the first connecting rod 231 are rotatably engaged with the first gripper 23 and the first frame 21, respectively. When the first cylinder 22 extends or retracts, the first gripper 23 swings through the hinge linkage of the first connecting rod 231 to press the end connecting plate 12 tightly against the first frame 21, which helps to enhance the stability and positioning accuracy of the clamping and reduce the loosening and displacement of the end connecting plate 12 during the welding process.

[0046] Reference Figure 4Two second end plate assemblies 3 are provided, and the two second end plate assemblies 3 are arranged facing each other. The second end plate assembly 3 includes a second frame 31, a third cylinder 32, a second cylinder 33, and a second gripper 34. The second frame 31 is fixedly installed on the first tooling frame, and the top of the second frame 31 is used to support another plate surface of the end connecting plate 12 with an end positioning hole 121. The third cylinder 32 is vertically fixedly installed on the second frame 31, and the piston rod of the third cylinder 32 is vertically fixedly installed with a first positioning pin 321. The third cylinder 32 can drive the first positioning pin 321 to be inserted into the end positioning hole 121 on one side of the end connecting plate 12 from below. In conjunction with the other second end plate assembly 3, the end positioning hole 121 on the other side of the end connecting plate 12 is positioned, thereby centering the end connecting plate 12 and improving the positioning accuracy. The second cylinder 33 is vertically fixed to the first tooling frame. The end of the second gripper 34 is rotatably engaged with the piston rod of the second cylinder 33. A second connecting rod 341 is provided between the middle of the second gripper 34 and the second frame 31. The two ends of the second connecting rod 341 are rotatably engaged with the second gripper 34 and the second frame 31, respectively. When the second cylinder 33 extends or retracts, the second gripper 34 swings through the hinge linkage of the second connecting rod 341, so as to press the end connecting plate 12 downward against the second frame 31, which is beneficial to further fix the end connecting plate 12. Together with the first end plate assembly 2, it forms a double clamping, suppressing the positional displacement caused by welding heat input.

[0047] Reference Figure 5 The first stiffening plate assembly 4 includes a first translation slide 41, a first slide cylinder 42, a stiffening positioning plate 43, a first clamping plate 44, and a first clamping cylinder 45. The first translation slide 41 slides along the first horizontal direction and is engaged with the first tooling frame via two slide rails. The first slide cylinder 42 is fixedly installed on the first tooling frame. The piston rod of the first slide cylinder 42 is connected to the first translation slide 41 so as to drive the first translation slide 41 to move horizontally closer to or away from the end stiffening plate 122, so as to perform clamping and removal operations on the end stiffening plate 122.

[0048] Two first clamping plates 44 are provided, each sliding along a second horizontal direction via two slide rails and engaging with a first translation slide 41. They are located on either side of a stiffening positioning plate 43, allowing for simultaneous clamping of two parallel end stiffening plates 122 by the central stiffening positioning plate 43 and the two side clamping plates 44. A first clamping cylinder 45 is positioned along a second horizontal direction, with both ends horizontally fixed to the two first clamping plates 44, enabling the two clamping plates 44 to move towards each other, thereby simultaneously pressing the two end stiffening plates 122 against both sides of the stiffening positioning plate 43.

[0049] Combination Figure 6A first positioning block 411 is fixedly installed on the top of the first translation slide 41. The first positioning block 411 is located between two first clamping plates 44. When both first clamping plates 44 are pressed against the end stiffening plates 122, the two first clamping plates 44 also simultaneously press against the two sides of the first positioning block 411 to ensure the accurate positioning of the two end stiffening plates 122. The stiffening positioning plate 43 is fixedly installed on the first tooling frame. The stiffening positioning plate 43 is equipped with a first limiting plate 431 and a second limiting plate 432. When the first sliding cylinder 42 moves the first translational sliding table 41 close to the end stiffening plate 122, the first limiting plate 431 can vertically abut against the end stiffening plate 122, and the second limiting plate 432 can horizontally abut against the end stiffening plate 122 towards the first frame 21. Thus, during subsequent clamping, the first limiting plate 431 and the second limiting plate 432 can respectively constrain the vertical warping and horizontal displacement of the end stiffening plate 122, which is beneficial to further reduce the slight displacement caused by welding thermal stress.

[0050] In addition, the top of one of the first clamping plates 44 is rotatably engaged with a first handle 441, and the top of the other first clamping plate 44 is rotatably engaged with a third link 442. The third link 442 is rotatably engaged with the middle of the first handle 441. The operator can manually lock the first clamping plate 44 by moving the first handle 441 to a horizontal position, which, through the third link 442, causes the two first clamping plates 44 to move further and tighten. This helps to reduce the attenuation of clamping force caused by gas source fluctuations during welding, and keeps the end stiffening plate 122 firmly clamped.

[0051] The implementation principle of the welding fixture system for a trailer hook beam in Embodiment 2 of this application is as follows: First, the end connecting plate 12 is placed on the first frame 21 and the second frame 31. The first cylinder 22 of the first end plate assembly 2 presses the top of one surface of the end connecting plate 12 against the first frame 21 through the hinge linkage of the first gripper 23 and the first connecting rod 231. At the same time, the third cylinder 32 of the second end plate assembly 3 drives the first positioning post 321 to insert into the end positioning hole 121 for hole centering. The second cylinder 33 presses the bottom of the other surface of the end connecting plate 12 against the second frame 31 through the second gripper 34 and the second connecting rod 341, thereby forming double clamping and precise positioning, which helps to enhance clamping stability and suppress the loosening and displacement of the end connecting plate 12 under welding heat input.

[0052] Subsequently, the first slide cylinder 42 of the first stiffening plate assembly 4 drives the first translation slide 41 to approach the two end stiffening plates 122 supported by the operator. The first clamping cylinder 45 drives the two first clamping plates 44 to move synchronously towards each other, pressing the two end stiffening plates 122 against both sides of the stiffening positioning plate 43. The first positioning block 411 precisely controls the spacing between the end stiffening plates 122. Furthermore, the first limiting plate 431 and the second limiting plate 432 on the stiffening positioning plate 43 abut against the end stiffening plates 122 to constrain vertical warping and horizontal displacement, thereby fixing the two end stiffening plates 122 to the first welding fixture.

[0053] Finally, the operator manually locks the end stiffener plate 122 by pulling the first handle 441 in conjunction with the third link 442, ensuring that the end stiffener plate 122 remains firmly clamped throughout the welding process and reducing loosening or displacement caused by gas source fluctuations or clamping force attenuation.

[0054] The first welding fixture precisely constrains the end connecting plate 12 and the end stiffening plate 122 to a predetermined relative position, so that the welding heat can be dispersed and input, and the component displacement caused by clamping deviation and thermal stress can be suppressed. At the same time, after welding is completed, the constraint can continue until cooling, which helps to suppress free deformation caused by residual stress release, thereby maintaining the positional accuracy of the positioning hole, providing a precise component foundation for the subsequent assembly of the crossbeam body 11, thereby reducing the technical effect of thermal deformation of the trailer crossbeam caused by welding.

[0055] Example 3: This application discloses a welding fixture system for a trailer hook crossbeam, used for welding and assembling the trailer hook crossbeam described in Example 1. (Refer to...) Figure 7 The welding fixture system for the trailer hook crossbeam includes a second welding fixture, which is used to assemble and weld the crossbeam body 11, end connecting plate 12, and middle connecting plate 13. The second welding fixture includes a second fixture frame, a third end plate assembly 5, a crossbeam assembly 6, and a middle assembly 7. The third end plate assembly 5, crossbeam assembly 6, and middle assembly 7 are all mounted on the second fixture frame, thus providing a stable mounting reference for each component and helping to ensure the accuracy and reliability of the clamping action.

[0056] Reference Figure 8Two third end plate assemblies 5 are provided, each used to fix two end connecting plates 12. Each third end plate assembly 5 includes an end plate placement platform 51, a fourth cylinder 52, a third gripper 53, a third frame 54, and a fifth cylinder 55. The end plate placement platform 51 is fixedly installed on the second tooling frame and supports a plate surface of the end connecting plate 12 with an end positioning hole 121. The fourth cylinder 52 is vertically fixedly installed on the second tooling frame, and the third gripper 53 is fixedly mounted on the piston rod of the fourth cylinder 52. The fourth cylinder 52 drives the third gripper 53 to move vertically. The third gripper 53 has an inclined portion 531 and two vertical portions 532. The inclined portion 531 can obliquely abut against one of the inner bends of the end connecting plate 12, that is, the plate surface of the end connecting plate 12 connecting to the crossbeam body 11. The two vertical portions 532 can vertically abut against the inner side of the other bend of the end connecting plate 12, that is, the end connecting plate 12 is locked onto the plate surface with the end positioning hole 121, and the two vertical portions 532 are respectively located on the outer side of the two end stiffening plates 122. Therefore, the third gripper 53 can apply clamping force to the end connecting plate 12 from two different directions at the same time, so that the end connecting plate 12 is pressed more evenly against the third frame 54 and the end plate placement platform 51.

[0057] The third frame 54 is fixedly installed on the second tooling frame and is used to cooperate with the third gripper 53 to form a clamping support. There are two fifth cylinders 55, which are arranged opposite each other. The fifth cylinder 55 is vertically fixedly installed on the third frame 54, and the piston rod of the fifth cylinder 55 is vertically fixedly installed with a second positioning pin 551. The fifth cylinder 55 is used to drive the second positioning pin 551 to vertically insert into the end positioning hole 121 on the corresponding side of the end connecting plate 12, thereby centering the end connecting plate 12 from both sides to reduce the deviation of the end connecting plate 12 during welding.

[0058] Reference Figure 9The crossbeam assembly 6 includes a crossbeam positioning seat 61, a sixth cylinder 62, a seventh cylinder 63, a fourth gripper 64, an eighth cylinder 65, and a fifth gripper 66. Two crossbeam positioning seats 61 are provided, and both are fixedly installed on the second tooling frame, respectively supporting both ends of the crossbeam body 11. The sixth cylinder 62 is vertically fixedly installed on the crossbeam positioning seat 61, and a third positioning pin 621 is vertically fixedly installed on the piston rod of the sixth cylinder 62. The sixth cylinder 62 drives the third positioning pin 621 to vertically insert into the crossbeam positioning hole 111, thereby centering the crossbeam body 11. Two seventh cylinders 63 are provided, located at both ends of the crossbeam positioning seat 61. The seventh cylinder 63 is vertically fixed to the second tooling frame, and the fourth gripper 64 is fixedly fixed to the piston rod of the seventh cylinder 63. The seventh cylinder 63 drives the fourth gripper 64 to vertically press the crossbeam body 11, causing the crossbeam body 11 to abut downward against the crossbeam positioning seat 61. The eighth cylinder 65 is horizontally fixed to the second tooling frame, and the fifth gripper 66 is fixedly fixed to the piston rod of the eighth cylinder 65. The eighth cylinder 65 drives the fifth gripper 66 to horizontally press the crossbeam body 11, causing the crossbeam body 11 to abut horizontally against the crossbeam positioning seat 61, thereby fixing the crossbeam body 11 within the rectangular hole of the crossbeam positioning seat 61. By centering the sixth cylinder 62 with the hole of the third positioning post 621, vertically pressing the seventh cylinder 63 with the fourth clamp 64, and horizontally pressing the eighth cylinder 65 with the fifth clamp 66, the crossbeam body 11 can form a four-way limit on the crossbeam positioning seat 61, which is beneficial to maintain the relative angle between the crossbeam body 11 and the end connecting plate 12 and suppress the positional displacement caused by welding heat input.

[0059] Reference Figure 10 The middle component 7 includes a second translation slide 71, a second slide cylinder 72, a connecting positioning plate 73, a second clamping plate 74, and a second clamping cylinder 75. The second translation slide 71 slides along a third horizontal direction and engages with the second tooling frame. The second slide cylinder 72 is fixedly installed on the second tooling frame, and the piston rod of the second slide cylinder 72 is fixedly connected to the second translation slide 71, so as to drive the second translation slide 71 to move horizontally towards or away from the middle connecting plate 13 along the third horizontal direction, thereby facilitating the clamping and removal of the middle connecting plate 13. The connecting positioning plate 73 is fixedly installed on the second tooling frame and is used to provide a positioning support surface for the middle connecting plate 13.

[0060] Two second clamping plates 74 are provided, and both second clamping plates 74 slide horizontally along the fourth horizontal direction and are engaged with the second translation slide 71. The two second clamping plates 74 are respectively located on both sides of the connecting positioning plate 73. The two ends of the second clamping cylinder 75 are respectively horizontally fixedly installed on the two second clamping plates 74. The second clamping cylinder 75 is used to drive the two second clamping plates 74 to move towards each other, thereby synchronously pressing the two middle connecting plates 13 against both sides of the connecting positioning plate 73, which is conducive to achieving synchronous positioning and clamping of the two middle connecting plates 13. The second translation slide 71 is fixedly installed with a second positioning block 711, which is located between the two second clamping plates 74. When both second clamping plates 74 are pressed against the middle connecting plate 13, the two second clamping plates 74 also simultaneously press against both sides of the second positioning block 711, thereby accurately defining the interval and position of the two middle connecting plates 13, which is conducive to maintaining the relative position consistency of the middle connecting plates 13 and the crossbeam body 11 during welding.

[0061] Combination Figure 11 The second clamping plate 74 is fixedly equipped with a fourth positioning post 741. When the second clamping plate 74 abuts against the middle connecting plate 13, the fourth positioning post 741 can be horizontally inserted into the middle positioning hole 131, thereby completing clamping and positioning simultaneously, which helps to reduce the clamping deviation of the middle connecting plate 13. In addition, the top of one of the second clamping plates 74 is rotatably engaged with a second handle 742, and the top of the other second clamping plate 74 is rotatably engaged with a fourth connecting rod 743. The fourth connecting rod 743 is rotatably engaged with the middle of the second handle 742. The operator can manually lock the two second clamping plates 74 by moving the second handle 742 to a horizontal position, which will cause further tightening displacement through the fourth connecting rod 743. This helps to reduce the occurrence of loosening or displacement of the middle connecting plate 13 due to gas source fluctuations or the decrease in clamping force of the second clamping cylinder 75 during the welding process, so that the middle connecting plate 13 remains stably clamped throughout the welding process.

[0062] The implementation principle of the welding fixture system for a trailer hook crossbeam in Embodiment 3 of this application is as follows: First, the end connecting plate 12 is placed between the end plate placement platform 51 and the third frame 54. The fourth cylinder 52 drives the third gripper 53 to move, and the inclined part 531 and the vertical part 532 respectively abut against the two inner sides of the bends of the end connecting plate 12, so that the end connecting plate 12 is evenly pressed against the third frame 54 and the end plate placement platform 51. At the same time, the two fifth cylinders 55 respectively drive the two second positioning pins 551 to insert into the end positioning holes 121, and center the end connecting plate 12, thereby suppressing the deviation of the end connecting plate 12 in subsequent welding. Then, the crossbeam body 11 is placed on the crossbeam positioning seat 61. The sixth cylinder 62 drives the third positioning pin 621 to insert into the crossbeam positioning hole 111 for hole centering. The seventh cylinder 63 drives the fourth clamp 64 to press the crossbeam body 11 downward. The eighth cylinder 65 drives the fifth clamp 66 to press the crossbeam body 11 horizontally, thereby making the crossbeam body 11 form a four-way limit and steadily maintaining the relative angle between the crossbeam body 11 and the end connecting plate 12.

[0063] Next, the second slide cylinder 72 drives the second translation slide 71 to approach the middle connecting plate 13, and the second clamping cylinder 75 drives the two second clamping plates 74 to move towards each other, clamping the two middle connecting plates 13 to both sides of the two connecting positioning plates 73 temporarily fixed by the operator. At the same time, the fourth positioning post 741 is inserted into the middle positioning hole 131 to achieve synchronous positioning, and the second positioning block 711 ensures the spacing accuracy of the middle connecting plates 13. Finally, the second handle 742 is pulled to manually lock the middle connecting plate through the fourth connecting rod 743.

[0064] Through the aforementioned multi-directional positioning and clamping, the second welding fixture precisely constrains the crossbeam body 11, end connecting plate 12, end stiffening plate 122, and middle connecting plate 13 to predetermined relative positions, thereby dispersing the welding heat input, which helps to suppress component displacement caused by thermal stress, and continues to maintain constraint after welding until cooling, suppressing free deformation caused by residual stress release, thus maintaining the positional accuracy of end positioning hole 121, middle positioning hole 131, and crossbeam positioning hole 111, so that the trailer hook crossbeam can be smoothly connected and installed with the vehicle longitudinal beam and other compatible components, reducing the thermal deformation of the trailer crossbeam caused by welding.

[0065] Example 4: This application discloses a welding fixture system for a trailer hook crossbeam, including the first welding fixture and the second welding fixture described in Examples 2 and 3.

[0066] Example 5: This application discloses a welding method for a trailer hook crossbeam, implemented using the welding fixture system for the trailer hook crossbeam described in Example 4, including the following specific steps: Step S1: Weld and fix the end stiffening plate 122 to the end connecting plate 12. Step S1 includes: Step S11: Clamp the end connecting plate 12. Place the end connecting plate 12 on the first frame 21 and the second frame 31 of the first welding fixture. Activate the first cylinder 22 of the first end plate assembly 2. The first cylinder 22, through the hinged linkage of the first gripper 23 and the first connecting rod 231, presses one surface of the end connecting plate 12 against the first frame 21. Simultaneously activate the third cylinders 32 of the two second end plate assemblies 3. The third cylinders 32 drive the first positioning pin 321 to insert into the end positioning holes 121 on both sides of the end connecting plate 12, centering the end connecting plate 12. Activate the second cylinder 33. The second cylinder 33, through the hinged linkage of the second gripper 34 and the second connecting rod 341, presses the other surface of the end connecting plate 12 downwards against the second frame 31, thereby completing the double clamping and positioning of the end connecting plate 12 on the first welding fixture.

[0067] Step S12: Clamp and weld the end stiffening plates 122. Support and position the two end stiffening plates 122 on both sides of the stiffening positioning plate 43. Activate the first slide cylinder 42 of the first stiffening plate assembly 4 to drive the first translation slide 41 closer to the end stiffening plates 122, so that the first limiting plate 431 abuts against the top surface of the end stiffening plate 122, and the second limiting plate 432 abuts against the side of the end stiffening plate 122 towards the first frame 21. Activate the first clamping cylinder 45 to drive the two first clamping plates 44 to move towards each other, synchronously pressing the two end stiffening plates 122 against the stiffening positioning plate 43, and using the first positioning block 411 to limit the distance between the two end stiffening plates 122. The operator pulls the first handle 441, which, through the third connecting rod 442, links the two first clamping plates 44 for manual locking. Subsequently, a welding robot welds the contact area between the end stiffener 122 and the end connecting plate 12, fixing the end stiffener 122 to the inner side of the bend in the end connecting plate 12. After welding, the first welding fixture is kept clamping the end connecting plate 12 and the end stiffener 122, allowing them to cool to room temperature under constraint. Then, the clamping parts are released, and the end connecting plate 12 assembly with the welded end stiffener 122 is removed.

[0068] Step S2: Weld and fix the crossbeam body 11, end connecting plate 12, and middle connecting plate 13 into an assembly. Step S2 includes: Step S21: Clamp the end connecting plate 12 assembly. Place the end connecting plate 12 assembly obtained in step S1 between the end plate placement platform 51 of the second welding fixture and the third frame 54. Activate the fourth cylinder 52 of the third end plate assembly 5 to drive the third gripper 53 to press down. The inclined portion 531 and the vertical portion 532 of the third gripper 53 respectively abut against the two inner bends of the end connecting plate 12, so that the end connecting plate 12 is evenly pressed against the third frame 54 and the end plate placement platform 51. Activate the two fifth cylinders 55 to drive the second positioning pin 551 to insert into the corresponding end positioning hole 121, completing the positioning of the end connecting plate 12.

[0069] Step S22: Clamp the crossbeam body 11. Place the crossbeam body 11 on the crossbeam positioning seat 61 and align the crossbeam positioning hole 111 with the third positioning post 621. Activate the sixth cylinder 62 of the crossbeam assembly 6 to drive the third positioning post 621 into the crossbeam positioning hole 111. Activate the two seventh cylinders 63 to drive the fourth gripper 64 to vertically press the crossbeam body 11; activate the eighth cylinder 65 to drive the fifth gripper 66 to horizontally press the crossbeam body 11, thereby forming a four-way limit on the crossbeam positioning seat 61.

[0070] Step S23: Clamp the middle connecting plate 13. Place the two middle connecting plates 13 against the two sides of the connecting positioning plate 73 respectively. Activate the second slide cylinder 72 of the middle component 7 to drive the second translation slide 71 closer to the middle connecting plate 13. Activate the second clamping cylinder 75 to drive the two second clamping plates 74 to move towards each other, pressing the middle connecting plate 13 against the connecting positioning plate 73. Simultaneously, insert the fourth positioning pin 741 into the middle positioning hole 131, and use the second positioning block 711 to ensure the spacing of the middle connecting plates 13. The operator pulls the second handle 742, which, through the fourth connecting rod 743, links the two second clamping plates 74 for manual locking.

[0071] Step S24: Welding and Cooling. A welding robot is used to weld the joints between the crossbeam body 11 and the end connecting plate 12 and the middle connecting plate 13, thus fixing the crossbeam body 11, end connecting plate 12, and middle connecting plate 13 together. After welding, the second welding fixture is maintained in a clamping state until the trailer hook crossbeam cools to room temperature under constraint. Then, the clamping components are released, and the welded trailer hook crossbeam is removed.

[0072] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A welding fixture system for a trailer hook crossbeam, characterized in that: For welding and assembling trailer hook crossbeams, the trailer hook crossbeam includes a crossbeam body (11), an end connecting plate (12), and a middle connecting plate (13). The end connecting plate (12) is welded and fixed to the end of the crossbeam body (11). The end connecting plate (12) is bent in an L-shape. An end stiffening plate (122) is welded and fixed to the inner side of the bend of the end connecting plate (12). The end connecting plate (12) has an end positioning hole (121) through it. The middle connecting plate (13) is welded and fixed to the middle of the crossbeam body (11). The middle connecting plate (13) has a middle positioning hole (131) through it. The crossbeam body (11) has a crossbeam positioning hole (111) through it. The crossbeam positioning hole (111) is located between the middle connecting plate (13) and the end connecting plate (12). The welding fixture system of the trailer hook crossbeam includes a first welding fixture and a second welding fixture. The first welding fixture is used to temporarily fix the end connecting plate (12) and the end stiffening plate (122) in step S1, wherein step S1 is to weld and fix the end stiffening plate (122) to the end connecting plate (12). The second welding fixture is used to temporarily fix the crossbeam body (11), the end connecting plate (12), the end stiffening plate (122) and the middle connecting plate (13) in step S2, wherein step S2 is to weld and fix the crossbeam body (11) to the end connecting plate (12) and to weld and fix the middle connecting plate (13) to the crossbeam body (11).

2. The welding fixture system for a trailer hook crossbeam according to claim 1, characterized in that: The first welding fixture includes a first fixture frame, a first end plate assembly (2), a second end plate assembly (3), and a first stiffening plate assembly (4); The first end plate assembly (2) includes a first frame (21), a first cylinder (22) and a first gripper (23). The first frame (21) is mounted on a first tooling frame, and the first cylinder (22) is mounted on the first frame (21). The first cylinder (22) causes the end connecting plate (12) to abut against the first frame (21) through the first gripper (23). The second end plate assembly (3) includes a second frame (31), a third cylinder (32), a second cylinder (33), and a second gripper (34). The second frame (31) is mounted on the first tooling frame. The third cylinder (32) is mounted on the second frame (31). The third cylinder (32) has a first positioning post (321) mounted vertically. The third cylinder (32) is used to make the first positioning post (321) vertically inserted into the end positioning hole (121). The second cylinder (33) is mounted on the first tooling frame. The second cylinder (33) makes the end connecting plate (12) abut against the second frame (31) through the second gripper (34). The first stiffening plate assembly (4) includes a first translation slide (41), a first slide cylinder (42), a stiffening positioning plate (43), a first clamping plate (44), and a first clamping cylinder (45). The first translation slide (41) is horizontally slidably fitted to the first tooling frame. The first slide cylinder (42) is used to make the first translation slide (41) horizontally approach or move away from the end stiffening plate (122). The stiffening positioning plate (43) is installed on the first tooling frame. The first clamping plate (44) is horizontally slidably fitted to the first translation slide (41). The first clamping cylinder (45) makes the end stiffening plate (122) abut against the stiffening positioning plate (43) through the first clamping plate (44).

3. The welding fixture system for a trailer hook crossbeam according to claim 2, characterized in that: The end of the first gripper (23) is rotatably engaged with the first cylinder (22), and a first connecting rod (231) is provided between the middle of the first gripper (23) and the first frame (21). The two ends of the first connecting rod (231) are rotatably engaged with the first gripper (23) and the first frame (21) respectively. The end of the second gripper (34) is rotatably engaged with the second cylinder (33). A second connecting rod (341) is provided between the middle of the second gripper (34) and the second frame (31). The two ends of the second connecting rod (341) are rotatably engaged with the second gripper (34) and the second frame (31), respectively.

4. The welding fixture system for a trailer hook crossbeam according to claim 2, characterized in that: The end connecting plate (12) is provided with two end stiffening plates (122), and the two end stiffening plates (122) are arranged in parallel. There are two first clamping plates (44), and the two first clamping plates (44) are respectively located on both sides of the stiffening positioning plate (43). The first translation slide (41) is equipped with a first positioning block (411), and the first positioning block (411) is located between the two first clamping plates (44). The two ends of the first clamping cylinder (45) are respectively horizontally installed on the two first clamping plates (44). In step S1, the two end stiffening plates (122) are respectively located in the gap between the two first clamping plates (44) and the stiffening positioning plate (43).

5. The welding fixture system for a trailer hook crossbeam according to claim 4, characterized in that: The reinforced positioning plate (43) is equipped with a first limiting plate (431) and a second limiting plate (432). In step S1, the first limiting plate (431) abuts vertically downward against the end reinforcing plate (122), and the second limiting plate (432) abuts horizontally against the end reinforcing plate (122) towards the first frame (21).

6. The welding fixture system for a trailer hook crossbeam according to claim 4, characterized in that: One of the first clamping plates (44) is rotatably fitted with a first handle (441), and the other first clamping plate (44) is rotatably fitted with a third link (442), the third link (442) being rotatably fitted at the middle of the first handle (441).

7. The welding fixture system for a trailer hook crossbeam according to claim 1, characterized in that: The second welding fixture includes a second fixture frame, a third end plate assembly (5), a crossbeam assembly (6), and a middle assembly (7); The third end plate assembly (5) includes an end plate placement platform (51), a fourth cylinder (52), a third gripper (53), a third frame (54), and a fifth cylinder (55). The end plate placement platform (51) is mounted on the second tooling frame. The fourth cylinder (52) is vertically mounted on the second tooling frame. The third gripper (53) is mounted on the fourth cylinder (52). The fourth cylinder (52) uses the third gripper (53) to cause the end connecting plate (12) to abut against the third frame (55). 4) The third gripper (53) can abut against the two inner sides of the bend of the end connecting plate (12) and make the end connecting plate (12) abut against the end plate placement platform (51). The third frame (54) is installed on the second tooling frame. The fifth cylinder (55) is vertically installed on the third frame (54). The fifth cylinder (55) is equipped with a second positioning post (551). The fifth cylinder (55) is used to make the second positioning post (551) vertically inserted into the end positioning hole (121). The crossbeam assembly (6) includes a crossbeam positioning seat (61), a sixth cylinder (62), a seventh cylinder (63), a fourth gripper (64), an eighth cylinder (65), and a fifth gripper (66). The crossbeam positioning seat (61) is mounted on the second tooling frame. The sixth cylinder (62) is vertically mounted on the crossbeam positioning seat (61). The sixth cylinder (62) is equipped with a third positioning post (621). The sixth cylinder (62) is used to vertically insert the third positioning post (621) into the crossbeam positioning hole (111). The seventh cylinder (63) is vertically mounted on the second tooling frame, and the fourth gripper (64) is mounted on the seventh cylinder (63). The seventh cylinder (63) uses the fourth gripper (64) to make the crossbeam body (11) abut downward against the crossbeam positioning seat (61). The eighth cylinder (65) is horizontally mounted on the second tooling frame, and the fifth gripper (66) is mounted on the eighth cylinder (65). The eighth cylinder (65) uses the fifth gripper (66) to make the crossbeam body (11) abut horizontally against the crossbeam positioning seat (61). The middle component (7) includes a second translation slide (71), a second slide cylinder (72), a connecting positioning plate (73), a second clamping plate (74), and a second clamping cylinder (75). The second translation slide (71) is horizontally slidably fitted to the second tooling frame. The second slide cylinder (72) is used to make the second translation slide (71) horizontally approach or move away from the middle connecting plate (13). The connecting positioning plate (73) is installed on the second tooling frame. The second clamping plate (74) is horizontally slidably fitted to the second translation slide (71). The second clamping plate (74) is equipped with a fourth positioning post (741). The second clamping cylinder (75) makes the middle connecting plate (13) abut against the connecting positioning plate (73) through the second clamping plate (74). When the second clamping plate (74) abuts against the middle connecting plate (13), the fourth positioning post (741) is horizontally inserted into the middle positioning hole (131).

8. The welding fixture system for a trailer hook crossbeam according to claim 7, characterized in that: The third gripper (53) is provided with an inclined portion (531) and a vertical portion (532). The inclined portion (531) can be inclined toward one of the inner sides of the bend of the end connecting plate (12), and the vertical portion (532) can be vertically toward the other inner side of the bend of the end connecting plate (12).

9. The welding fixture system for a trailer hook crossbeam according to claim 7, characterized in that: Two central connecting plates (13) are provided, and the two central connecting plates (13) are arranged in parallel. Two second clamping plates (74) are provided. The second translation slide (71) is equipped with a second positioning block (711). The second positioning block (711) is located between the two second clamping plates (74). The two second clamping plates (74) are respectively located on both sides of the connecting positioning plate (73). The two ends of the second clamping cylinder (75) are respectively horizontally installed on the two second clamping plates (74). In step S2, the two central connecting plates (13) are respectively located in the gap between the two second clamping plates (74) and the connecting positioning plate (73).

10. The welding fixture system for a trailer hook crossbeam according to claim 7, characterized in that: One of the second clamping plates (74) is rotatably coupled with a second handle (742), and the other second clamping plate (74) is rotatably coupled with a fourth link (743), which is rotatably coupled to the middle of the second handle (742).

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