Symmetrical welding device and process for thick plate of bridge steel structure capable of eliminating stress

Abstract

The application relates to the technical field of steel structure welding, and discloses a stress-eliminating symmetrical welding device and process for bridge steel structure thick plates, wherein the stress-eliminating symmetrical welding device for bridge steel structure thick plates comprises a jig main body, a plurality of bottom plates fixedly connected to the bottom of the jig main body, a turnover plate fixedly connected to the bottom of the bottom plate, a T-shaped frame arranged on one side of the turnover plate, two guide wheels rotatably connected to the T-shaped frame, a sliding sleeve fixedly connected below the T-shaped frame, a lead screw threadedly and drivably connected in the sliding sleeve, bending pieces symmetrically arranged on the two lengthwise sides of the jig main body, and the bending pieces are rotatably connected to the jig main body. Relying on the precise linkage of the T-shaped frame, the rack and the positioning plate, the integrated operation of the single power source orderly driving the pre-bending of the steel plate and the turnover of the jig is realized. The design discards the traditional multi-component dispersed power structure, simplifies the operation process, reduces the energy consumption and the equipment cost.

Description

Technical Field

[0001] This invention relates to the field of steel structure welding technology, and in particular to a stress-relieving symmetrical welding device and process for thick plates of bridge steel structures. Background Technology

[0002] In bridge steel structure manufacturing, the welding of orthotropic plate units is a core process for controlling the overall quality of the beam segment. This plate unit is mainly formed by welding a thick steel plate top plate with multiple U-shaped longitudinal stiffening ribs through continuous fillet welds on both sides. Due to the dense arrangement of the U-shaped ribs, the long welding process, and the fact that welding is only performed on one side of the panel, a large temperature gradient will be formed in the thickness direction of the steel plate. After welding, four types of defects are prone to occur: longitudinal shrinkage, transverse shrinkage, longitudinal out-of-plane bending, and angular deformation, which directly affect the forming accuracy of the plate unit and the stability of the bridge structure.

[0003] Currently, the industry generally adopts the reverse deformation jig process to control welding deformation. By applying hydraulic or mechanical pressure, the steel plate is pre-pressed with a reverse curvature, and welding is completed in a fixed and pressed position. The pre-set reverse deformation is used to offset the shrinkage deformation after welding, which is the mainstream deformation control method at present.

[0004] However, existing complete sets of equipment have significant technical shortcomings. The core issue is that the bending and tilting mechanisms use independent power systems. During construction, the steel plate bending and jig tilting processes must be completed in stages, resulting in cumbersome process connections, significantly extending the overall welding period, and leading to low production efficiency. Furthermore, the bending mechanism is directly integrated into the tilting jig body, requiring the tilting mechanism to additionally bear the weight of the bending mechanism. This significantly increases the tilting drive torque and operating power, not only wasting energy but also necessitating the selection of large-scale tilting motors, reducers, and slewing bearings, significantly increasing equipment manufacturing, procurement, and subsequent maintenance costs. This hinders the efficient and low-cost mass production of bridge steel structure welding. Summary of the Invention

[0005] Given that existing anti-deformation jigs have independent bending and turning forces, resulting in complicated procedures, low efficiency, and high energy consumption and cost, a stress-relieving symmetrical welding device for thick plates of bridge steel structures is proposed.

[0006] Its purpose is to achieve an integrated power design for bending and turning mechanisms, reduce equipment complexity and jig load, and optimize welding production efficiency.

[0007] The technical solution of this invention is a stress-relieving symmetrical welding device for thick plates of bridge steel structures, comprising a jig body and multiple base plates fixedly connected to the bottom of the jig body. A flipping plate is fixedly connected to the bottom of each base plate. A T-shaped frame is provided on one side of each flipping plate. Two guide wheels are rotatably connected to the T-shaped frame, and the guide wheels are in rolling contact with the flipping plate. A sliding sleeve is fixedly connected below the T-shaped frame, and a lead screw is threaded into the sliding sleeve. One end of the lead screw is connected to a motor. Bending members are symmetrically arranged on both sides of the jig body along its length. The bending members are rotatably connected to the jig body. A gear is rotatably connected to the bottom of each base plate, and the gear is connected to the bending members. A rack is meshed with one side of the gear. A guide rail is fixedly connected to the bottom of the base plate. The rack is slidably sleeved on the guide rail. A positioning plate is vertically slidably arranged at one end of the rack, and the positioning plate abuts against the T-shaped frame. A positioning groove adapted to the positioning plate is provided at one end of the guide rail.

[0008] Furthermore, the flip plate is provided with a guide surface, the guide wheel is in rolling contact with the guide surface, and the outline of the guide surface is a symmetrical groove-like structure with an upward opening.

[0009] Furthermore, both ends of the lead screw are rotatably connected to a base, and two slide rods are fixedly connected between the two bases. The two slide rods are horizontally and symmetrically distributed on both sides of the lead screw, and the sliding sleeve is slidably sleeved on the slide rods.

[0010] Furthermore, the T-shaped frame is positioned below the rack, and the lower part of the positioning plate and the upper part of the T-shaped frame are both provided with mutually fitting inclined surfaces.

[0011] Furthermore, the bending member includes a connecting rod, on which rotating plates are fixedly connected at equal intervals. An abutment block is fixedly connected to the upper end of the rotating plate, and a connecting plate is rotatably connected to the rotating plate. The connecting plate is fixedly connected to the main body of the jig.

[0012] Furthermore, a transmission rod is provided between the gear and the connecting rod, and ball heads are fixedly provided at both ends of the transmission rod. Connecting seats are rotatably sleeved on the ball heads, and the two connecting seats are rotatably connected to the connecting rod and the gear respectively.

[0013] Furthermore, a protrusion is fixed on one side of the positioning plate, and an L-shaped rod is rotatably connected inside the rack. One end of the L-shaped rod is positioned above the protrusion, and a push rod is hinged to the other end of the L-shaped rod. The lower end of the push rod extends to below the rack.

[0014] Furthermore, an arc-shaped ring with a superior arc structure is rotatably connected inside the connecting plate, a counterweight is fixedly connected below the arc-shaped ring, and two arc-shaped grooves adapted to the arc-shaped ring are opened on the rotating plate.

[0015] Another objective of this invention is to provide a symmetrical welding process for thick plates of bridge steel structures, the purpose of which is to complete pre-deformation, flipping, and welding in one integrated manner, thereby offsetting welding deformation and ensuring the forming accuracy of the components.

[0016] To achieve the above objectives, the present invention provides the following technical solution: a symmetrical welding process for thick plates of bridge steel structures, comprising the following steps: S1. Workpiece positioning: Place the thick steel plate and U-shaped rib on the main body of the jig according to the design position, with the bending parts on both sides in the initial lifted state, to complete the rough alignment of the workpiece. S2, Pre-deformation of bending: Start the motor, the screw drives the sliding sleeve to move, the T-shaped frame abuts against the positioning plate and drives the rack to move horizontally, the gear rotates and drives the upper end of the bending piece to bend the steel plate downward to the preset reverse deformation amount; S3, Tire frame flipping: The motor continues to rotate in the same direction, the guide wheel moves along the contact surface of the flipping plate, and pushes the flipping plate and the main body of the tire frame to flip to the ship-shaped welding position; S4. Symmetrical welding and resetting: Symmetrical fillet welding is performed on both sides of the U-rib in the flipped state. After welding, the motor reverses and the device is reset in sequence. The steel plate springs back to a flat state, and the welding stress and pre-deformation cancel each other out.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. Utilizing the precise linkage of the T-shaped frame, rack, and positioning plate, this system achieves integrated operation of pre-bending and jig rotation driven by a single power source. During power drive, the equipment first pushes the rack and gear transmission to complete the precise pre-bending of the steel plate. The positioning structure locks the forming posture, effectively preventing workpiece springback during welding and offsetting residual welding stress. After pre-bending and locking, the mechanism continues to move forward, using the cooperation of guide wheels and guide surfaces to rotate the jig as a whole, switching the welding surface to the standard ship-shaped welding station. This design abandons the traditional multi-set distributed power structure, simplifying the operation process, reducing energy consumption and equipment costs. At the same time, it eliminates the bending mechanism on the traditional jig, significantly reducing the load on the jig rotation and improving operational stability.

[0018] 2. The precise engagement of the arc-shaped ring and arc-shaped groove creates a secondary mechanical lock on the bending mechanism. This distributes welding vibration and workpiece springback load, preventing stress concentration on the gear and rack transmission pairs, effectively reducing tooth surface wear and extending the service life of the transmission structure. Simultaneously, it stably locks the pre-deformation of the steel plate, preventing bending misalignment and springback failure, ensuring welding accuracy, and reducing equipment maintenance costs. Attached Figure Description

[0019] Figure 1 This is a three-dimensional schematic diagram of the overall structure of the stress-relief symmetrical welding device for thick plates of bridge steel structures according to the present invention. Figure 2This is a front view schematic diagram of the overall structure of the stress-relief symmetrical welding device for thick plates of bridge steel structures according to the present invention. Figure 3 This is a schematic diagram of the lead screw and sliding sleeve structure of the stress-relieving symmetrical welding device for thick plates of bridge steel structures according to the present invention. Figure 4 This is a schematic diagram of the guide wheel and flipping plate structure of the stress-relieving symmetrical welding device for thick plates of bridge steel structures according to the present invention. Figure 5 This is a schematic diagram of the T-shaped frame and positioning plate structure of the stress-relieving symmetrical welding device for thick plates of bridge steel structures according to the present invention. Figure 6 This is a schematic diagram of the bending component structure of the stress-relieving symmetrical welding device for thick plates of bridge steel structures according to the present invention. Figure 7 This is a schematic diagram of the transmission rod, connecting rod, and gear structure of the stress-relieving symmetrical welding device for thick plates of bridge steel structures according to the present invention. Figure 8 This is a top view of the transmission rod, connecting rod, and gear structure of the stress-relieving symmetrical welding device for thick plates of bridge steel structures according to the present invention. Figure 9 This is a schematic diagram of the internal structure of the rack of the stress-relieving symmetrical welding device for thick plates of bridge steel structures according to the present invention. Figure 10 This is a schematic diagram of the arc-shaped ring and rotating plate structure of the stress-relieving symmetrical welding device for thick plates of bridge steel structures according to the present invention. Figure 11 This is a schematic plan view of the arc-shaped ring and rotating plate structure of the stress-relieving symmetrical welding device for thick plates of bridge steel structures according to the present invention. Figure 12 This is a schematic diagram of the bending component and the steel plate of the stress-relieving symmetrical welding device for thick plates of bridge steel structures according to the present invention.

[0020] In the picture: 1. Main body of the jig; 2. Base plate; 3. Tilting plate; 4. Guide surface; 5. T-shaped frame; 6. Guide wheel; 7. Lead screw; 8. Sliding sleeve; 9. Base; 10. Sliding rod; 11. Motor; 12. Press-bending component; 121. Connecting rod; 122. Rotating plate; 123. Abutment block; 124. Connecting plate; 13. Gear; 14. Rack; 15. Guide rail; 16. Positioning plate; 17. Positioning groove; 18. Transmission rod; 19. Ball head; 20. Connecting seat; 21. Protrusion; 22. L-shaped rod; 23. Arc ring; 24. Counterweight; 25. Arc groove; 26. Push rod. Detailed Implementation

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0022] Example 1, referring to Figures 1-5 This invention provides a stress-relieving symmetrical welding device for thick plates of bridge steel structures, comprising a jig body 1 and multiple base plates 2 fixedly connected to the bottom of the jig body 1. A flip plate 3 is fixedly connected to the bottom of the base plate 2. A T-shaped frame 5 is provided on one side of the flip plate 3. Two guide wheels 6 are rotatably connected to the T-shaped frame 5, and the guide wheels 6 roll in contact with the flip plate 3. A sliding sleeve 8 is fixedly connected below the T-shaped frame 5. A lead screw 7 is threaded into the sliding sleeve 8, and a motor 11 is connected to one end of the lead screw 7. A bending member 12 is symmetrically arranged on both sides of the body 1 along its length. The bending member 12 is rotatably connected to the main body 1 of the frame. A gear 13 is rotatably connected to the bottom of the base plate 2. The gear 13 is connected to the bending member 12 in a transmission manner. A rack 14 is meshed with one side of the gear 13. A guide rail 15 is fixedly connected to the bottom of the base plate 2. The rack 14 is slidably sleeved on the guide rail 15. A positioning plate 16 is vertically slidably arranged at one end of the rack 14. The positioning plate 16 abuts against the T-shaped frame 5. A positioning groove 17 adapted to the positioning plate 16 is opened at one end of the guide rail 15.

[0023] Specifically, the motor 11 drives the lead screw 7 to rotate, causing the sliding sleeve 8 and the T-shaped frame 5 to move synchronously, and the guide wheel 6 rolls smoothly along the surface of the flipping plate 3. During the movement of the T-shaped frame 5, it first touches the positioning plate 16, pushes the rack 14 to slide along the guide rail 15, and then drives the meshing gear 13 to rotate, causing the two side bending parts 12 to rotate around the hinge point towards the top surface of the jig body 1, and precisely presses the steel plate to the preset anti-deformation size. After the pre-pressing is completed, the T-shaped frame 5 continues to move forward, and with the transmission cooperation between the guide wheel 6 and the flipping plate 3, it pushes the jig body 1 to flip as a whole, so that the welding area of ​​the steel plate and the U-shaped rib plate is turned to the ship-shaped welding station. After the welding on one side is completed, the motor 11 rotates in the opposite direction, drives the mechanism to move again, and flips the welding surface of the other side of the workpiece to the working position, and completes all welding processes in sequence. This device relies on a single power unit to synchronously achieve bending pre-deformation and jig flipping, with seamless process connection and effective reduction of jig weight. It greatly simplifies the operation process, reduces equipment energy consumption and maintenance costs, effectively offsets welding deformation and residual stress, and improves component forming accuracy and production efficiency.

[0024] Reference Figure 3 , Figure 4 The flip plate 3 is provided with a guide surface 4, and the guide wheel 6 rolls in contact with the guide surface 4. The outline of the guide surface 4 is a symmetrical groove-shaped structure with the opening facing upward.

[0025] Specifically, the guide surface 4 consists of a middle plane and inclined surfaces extending upward at both ends. When the guide wheel 6 rolls on the plane section, it works with the T-shaped frame 5 to support the main body 1 of the jig and maintain a horizontal posture. When the guide wheel 6 moves along the inclined surface, it pushes the flipping plate 3 to rotate synchronously with the main body 1 of the jig. When the guide wheel 6 reaches the end of the inclined surface, the main body 1 of the jig can accurately flip the workpiece to the ship-shaped welding station.

[0026] Reference Figure 2 , Figure 3 Both ends of the lead screw 7 are rotatably connected to bases 9, and two slide rods 10 are fixedly connected between the two bases 9. The two slide rods 10 are horizontally symmetrically distributed on both sides of the lead screw 7, and the sliding sleeve 8 is slidably sleeved on the slide rods 10.

[0027] Specifically, when the lead screw 7 rotates to drive the sliding sleeve 8 to move linearly, the slide rod 10 can play a limiting and guiding role for the sliding sleeve 8, effectively preventing the sliding sleeve 8 from deflecting or jamming during operation, ensuring smooth and stable overall transmission action, and improving the stability and transmission accuracy of the mechanism.

[0028] Reference Figure 4 , Figure 5 The T-shaped frame 5 is located below the rack 14, and the lower part of the positioning plate 16 and the upper part of the T-shaped frame 5 are both provided with mutually fitting inclined surfaces.

[0029] Specifically, during the forward movement of the T-shaped frame 5, its upper inclined surface closely abuts against the lower inclined surface of the positioning plate 16. Due to the limiting effect of the guide rail 15, the upper end of the positioning plate 16 cannot be lifted upward, thereby transmitting the horizontal thrust to the rack 14, driving the rack 14 to slide precisely along the guide rail 15, completing the transmission action of the steel plate pre-bending. When the rack 14 moves with the positioning plate 16 to directly below the positioning groove 17, the left end of the rack 14 abuts against the guide rail 15 and cannot continue to slide. At this time, the T-shaped frame 5 continues to move forward, pushing the positioning plate 16 vertically upward through the pressure of the inclined surface, so that the upper end of the positioning plate 16 is inserted into the positioning groove 17, which can effectively lock the reverse displacement of the rack 14, fix the transmission position of the rack 14 and the gear 13, and finally realize the reliable locking of the bending posture of the bending part 12, ensuring the precise and constant pre-deformation of the steel plate, avoiding deformation and springback during welding, and greatly improving the bending positioning accuracy and operational stability of the device.

[0030] Reference Figure 1 , Figure 6 The bending member 12 includes a connecting rod 121, a rotating plate 122 fixedly connected at equal intervals on the connecting rod 121, an abutment block 123 fixedly connected to the upper end of the rotating plate 122, and a connecting plate 124 rotatably connected to the rotating plate 122. The connecting plate 124 is fixedly connected to the frame body 1.

[0031] Specifically, when the gear 13 is driven to rotate by the rack 14, it can drive the connecting rod 121 to move away from the main body 1 of the jig, causing each rotating plate 122 to rotate and swing based on the hinge fulcrum formed by the connecting plate 124. This causes the top abutment block 123 to flip and press down towards the top surface of the jig body 1. Multiple sets of abutment blocks 123 arranged at equal intervals simultaneously apply uniform pressure to the steel plate, smoothly completing the pre-bending forming operation of the steel plate. The overall structure is uniformly stressed and has strong bending synchronization, which can effectively ensure that the overall pre-deformation of the steel plate is uniform and consistent, avoid local bending deviations, and greatly improve the forming accuracy of the pre-deformation of the steel plate welding.

[0032] Reference Figure 7 , Figure 8 A transmission rod 18 is provided between the gear 13 and the connecting rod 121. Ball heads 19 are fixedly provided at both ends of the transmission rod 18. Connecting seats 20 are rotatably sleeved on the ball heads 19. The two connecting seats 20 are rotatably connected to the connecting rod 121 and the gear 13 respectively.

[0033] Specifically, during the rotation of gear 13, the universal transmission structure formed by end connecting seat 20, ball head 19 and transmission rod 18 can smoothly transmit rotational power to connecting rod 121, causing the connecting rod 121 to move away from the main body 1 of the frame. With the spherical rotation adaptability of ball head 19 and connecting seat 20, the angular deviation and position error during the transmission process can be effectively compensated, avoiding the phenomena of jamming, stress concentration and transmission jamming in rigid transmission, and the power transmission is smoother and more stable.

[0034] Example 2, refer to Figure 4 , Figure 9 This is the second embodiment of the present invention. The difference between this embodiment and the first embodiment is that: a protrusion 21 is fixedly provided on one side of the positioning plate 16, and an L-shaped rod 22 is rotatably connected inside the rack 14. One end of the L-shaped rod 22 is located above the protrusion 21, and a push rod 26 is hinged to the other end of the L-shaped rod 22. The lower end of the push rod 26 extends to the bottom of the rack 14.

[0035] Specifically, after the welding operation is completed, the T-shaped frame 5 moves from the right end of the flip plate 3 towards the center, and its upper inclined surface abuts against and pushes the lower end of the push rod 26, causing the L-shaped rod 22 to rotate counterclockwise around the hinge point; the upper end of the L-shaped rod 22 swings downward simultaneously and presses the protrusion 21, driving the positioning plate 16 to move down as a whole, so that the positioning plate 16 completely disengages from the positioning groove 17, releasing the locking limit on the rack 14. After the lock is released, the bending part 12 automatically rotates back to its original position by its own gravity, and drives the gear 13 and rack 14 back to their initial position through the transmission rod 18, completing the automatic reset of the entire bending mechanism. The structure has strong linkage and the unlocking and reset actions are completed automatically, without the need for additional manual operation, effectively simplifying the process and improving the automation level and work efficiency of the equipment.

[0036] Among them, reference Figure 4The coordination states of each structure in this device are as follows: When the guide wheel 6 moves to the left along the plane of the guide surface 4, the T-shaped frame 5 and the positioning plate 16 cooperate to drive the rack 14 to move along the guide rail 15, and the gear 13 and the transmission rod 18 cooperate to drive the bending member 12 to bend the steel plate; when the guide wheel 6 moves along the left inclined plane of the guide surface 4, the jig body 1 rotates counterclockwise and tilts, causing the right welding surface between the steel plate and the U-shaped rib to flip to the ship-shaped welding position; when the guide wheel 6 moves along the left inclined plane of the guide surface 4, the jig body 1 returns from tilt to horizontal, and at this time, when the T-shaped frame 5 moves to the right, it interacts with the push rod 26. When the counterclockwise deflection does not cause the L-shaped rod 22 to rotate, the bending component 12 continues to maintain contact with the steel plate; when the guide wheel 6 moves to the right inclined plane along the guide surface 4, the main body 1 of the jig rotates clockwise and tilts, causing the left welding surface between the steel plate and the U-shaped rib to flip to the ship-shaped welding position; when the guide wheel 6 moves from the side inclined plane along the guide surface 4, the main body 1 of the jig returns from tilt to horizontal, the inclined plane of the T-shaped frame 5 lifts the lower end of the push rod 26, causing the L-shaped rod 22 to rotate counterclockwise, canceling the connection between the positioning plate 16 and the positioning groove 17, and the bending component 12 automatically resets and cancels the limit on the steel plate.

[0037] Reference Figure 10 , Figure 11 An arc-shaped ring 23 with a superior arc structure is rotatably connected inside the connecting plate 124. A counterweight block 24 is fixedly connected below the arc-shaped ring 23, and two arc-shaped grooves 25 adapted to the arc-shaped ring 23 are opened on the rotating plate 122.

[0038] Specifically, when the rotating plate 122 is in a vertical initial state, the arc groove 25 and the end of the arc ring 23 are misaligned, and the end of the arc ring 23 cannot be embedded in the arc groove 25, so that the rotating plate 122 maintains a stable initial posture. When the rotating plate 122 deflects and performs a bending operation on the steel plate, the arc groove 25 is precisely aligned with the end of the arc ring 23. When the main body 1 of the jig tilts and flips, the counterweight 24 uses its own weight to keep the arc ring 23 in a fixed posture and not deflect with the jig. Meanwhile, the rotating plate 122 tilts and rotates synchronously with the main body 1 of the jig, causing the end of the arc ring 23 to be precisely inserted into the corresponding arc groove 25. This structure can provide secondary locking and restraint for the bent component 12 during the welding process of the jig flipping. The external forces generated by welding vibration and workpiece springback can be directly absorbed and distributed by the arc-shaped ring 23 and arc-shaped groove 25, preventing the entire load from being concentrated on the meshing transmission pair of gear 13 and rack 14. This effectively reduces the contact pressure on the meshing surfaces of gear 13 and rack 14, significantly reducing frictional loss and extrusion wear on the transmission tooth surfaces, and avoiding problems such as tooth surface wear, increased meshing clearance, and transmission accuracy deviation that occur during long-term operation. Simultaneously, it prevents the bent component 12 from loosening or shifting due to external forces, continuously locking the pre-compression deformation of the steel plate, preventing workpiece springback and bending accuracy failure during welding. This ensures both welding accuracy and equipment operational stability, effectively extends the service life of the gear 13 and rack 14 transmission structure, and reduces equipment maintenance costs. The remaining structures are the same as in Example 1.

[0039] Based on embodiments 1-2, the working principle of this invention is as follows: The device relies on a linkage mechanism driven by a single motor 11 to simultaneously achieve pre-pressure bending deformation of the steel plate and the flipping welding of the jig, effectively offsetting residual welding stress. During operation, the motor 11 drives the lead screw 7 to rotate, causing the T-shaped frame 5 with the sliding sleeve 8 to move smoothly along the sliding rod 10. The guide wheel 6 rolls along the symmetrical grooved guide surface 4 of the flipping plate 3. When the T-shaped frame 5 moves forward, it pushes against the positioning plate 16 through the inclined surface, causing the rack 14 to slide along the guide rail 15, driving the meshing gear 13 to rotate. This rotation is transmitted through the transmission rod 18 with the ball head 19 and the connecting seat 20, causing the rotating plate 122 of the bending member 12 to deflect around the connecting plate 124. Multiple sets of abutment blocks 123 evenly press the steel plate, completing the preset anti-deformation pre-pressure. After pre-pressing, the positioning plate 16 engages with the positioning groove 17 of the guide rail 15, locking the rack 14 into the bending posture. The T-shaped frame 5 continues to move forward, and the guide wheel 6 rolls along the inclined surface of the guide surface 4, pushing the jig body 1 to flip, switching the welding area to the ship-shaped welding station. Flipping forward and backward can complete welding on both sides of the workpiece. After welding is completed, the T-shaped frame 5 retracts the push rod 26, causing the L-shaped rod 22 to rotate, and the pressing protrusion 21 causes the positioning plate 16 to disengage from the positioning groove 17. After unlocking the limit, the bent part 12 automatically resets.

[0040] Example 3, referring to Figures 1-12 The third embodiment of the present invention provides: a symmetrical welding process for thick plates of bridge steel structures, comprising the following steps: S1. Workpiece positioning: Place the thick steel plate and U-shaped rib on the main body 1 of the jig according to the design position, with the two side bending parts 12 in the initial lifted state, to complete the rough alignment of the workpiece. S2, Pre-deformation of bending: Start motor 11, lead screw 7 drives sliding sleeve 8 to move, T-shaped frame 5 abuts against positioning plate 16 to drive rack 14 to move horizontally, gear 13 rotates to drive the upper end of bending piece 12 to bend the steel plate downward to the preset reverse deformation amount. S3, Tire frame flipping: Motor 11 continues to rotate in the same direction, guide wheel 6 moves along the contact surface of flipping plate 3, pushing flipping plate 3 and tire frame body 1 to flip as a whole to the ship-shaped welding position; S4. Symmetrical welding and resetting: Symmetrical fillet welding is performed on both sides of the U-rib in the flipped state. After welding, motor 11 reverses and the device is reset in sequence. The steel plate springs back to a flat state, and the welding stress and pre-deformation cancel each other out.

[0041] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A stress-relief symmetrical welding device for thick plates of bridge steel structures, comprising a jig body (1), characterized in that, It also includes multiple base plates (2) fixedly connected to the bottom of the main body (1) of the frame. A flip plate (3) is fixedly connected to the bottom of the base plate (2). A T-shaped frame (5) is provided on one side of the flip plate (3). Two guide wheels (6) are rotatably connected on the T-shaped frame (5). The guide wheels (6) are in rolling contact with the flip plate (3). A sliding sleeve (8) is fixedly connected below the T-shaped frame (5). A screw (7) is threadedly driven and connected to the sliding sleeve (8). A motor (11) is driven and connected to one end of the screw (7). The main body (1) of the frame is symmetrically provided with bending members (12) on both sides along its length. The bending members (12) are rotatably connected to the main body (1). The bottom plate (2) is rotatably connected with a gear (13). The gear (13) is connected to the bending members (12) in a transmission manner. A rack (14) is meshed with one side of the gear (13). A guide rail (15) is fixedly connected to the bottom of the bottom plate (2). The rack (14) is slidably sleeved on the guide rail (15). A positioning plate (16) is vertically slidably provided at one end of the rack (14). The positioning plate (16) abuts against the T-shaped frame (5). A positioning groove (17) adapted to the positioning plate (16) is opened at one end of the guide rail (15).

2. The stress-relief symmetrical welding device for thick plates of bridge steel structures according to claim 1, characterized in that, The flip plate (3) is provided with a guide surface (4), the guide wheel (6) rolls in contact with the guide surface (4), and the outline of the guide surface (4) is a symmetrical groove-shaped structure with an upward opening.

3. The stress-relief symmetrical welding device for thick plates of bridge steel structures according to claim 1, characterized in that, Both ends of the lead screw (7) are rotatably connected to bases (9), and two slide rods (10) are fixedly connected between the two bases (9). The two slide rods (10) are horizontally symmetrically distributed on both sides of the lead screw (7), and the sliding sleeve (8) is slidably sleeved on the slide rods (10).

4. The stress-relief symmetrical welding device for thick plates of bridge steel structures according to claim 1, characterized in that, The T-shaped frame (5) is located below the rack (14), and the lower part of the positioning plate (16) and the upper part of the T-shaped frame (5) are provided with mutually fitting inclined surfaces.

5. The stress-relief symmetrical welding device for thick plates of bridge steel structures according to claim 1, characterized in that, The bending member (12) includes a connecting rod (121), a rotating plate (122) is fixedly connected at equal intervals on the connecting rod (121), an abutment block (123) is fixedly connected to the upper end of the rotating plate (122), a connecting plate (124) is rotatably connected to the rotating plate (122), and the connecting plate (124) is fixedly connected to the frame body (1).

6. The stress-relief symmetrical welding device for thick plates of bridge steel structures according to claim 5, characterized in that, A transmission rod (18) is provided between the gear (13) and the connecting rod (121). Ball heads (19) are fixedly provided at both ends of the transmission rod (18). Connecting seats (20) are rotatably sleeved on the ball heads (19). The two connecting seats (20) are rotatably connected to the connecting rod (121) and the gear (13) respectively.

7. The stress-relief symmetrical welding device for thick plates of bridge steel structures according to claim 1, characterized in that, A protrusion (21) is fixed on one side of the positioning plate (16), and an L-shaped rod (22) is rotatably connected inside the rack (14). One end of the L-shaped rod (22) is located above the protrusion (21), and the other end of the L-shaped rod (22) is hinged to a push rod (26). The lower end of the push rod (26) extends to below the rack (14).

8. The stress-relief symmetrical welding device for thick plates of bridge steel structures according to claim 5, characterized in that, The connecting plate (124) is rotatably connected to an arc ring (23) with a superior arc structure. A counterweight (24) is fixedly connected below the arc ring (23), and two arc grooves (25) adapted to the arc ring (23) are opened on the rotating plate (122).

9. A symmetrical welding process for thick plates of bridge steel structures, applied to the stress-relief symmetrical welding device for thick plates of bridge steel structures as described in claim 1, characterized in that... Includes the following steps: S1. Workpiece positioning: Place the thick steel plate and U-shaped rib on the main body of the jig (1) according to the design position, and the two side bending parts (12) are in the initial lifting state to complete the rough alignment of the workpiece; S2, Pre-deformation of bending: Start the motor (11), the lead screw (7) drives the sliding sleeve (8) to move, the T-shaped frame (5) abuts against the positioning plate (16) to drive the rack (14) to move horizontally, the gear (13) rotates to drive the upper end of the bending piece (12) to bend the steel plate downward to the preset reverse deformation amount; S3, Tire frame flipping: The motor (11) continues to rotate in the same direction, the guide wheel (6) moves along the contact surface of the flipping plate (3), and pushes the flipping plate (3) and the main body of the tire frame (1) to flip as a whole to the ship-shaped welding position; S4. Symmetrical welding and resetting: Symmetrical fillet welding is performed on both sides of the U-rib in the flipped state. After welding, the motor (11) reverses and the device is reset in sequence. The steel plate springs back to a flat state, and the welding stress and pre-deformation cancel each other out.

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