Suspension bridge steel box girder hoisting hoist and hoisting method

Abstract

The present application relates to steel box girder hoisting technical field, and disclose a kind of suspension bridge steel box girder hoist and hoisting method.The suspension bridge steel box girder hoist includes top plate and lifting plate, and lifting plate is provided with installation limiting prompting mechanism.The present application is realized by setting up synchronous component, four clamping points are mechanically linked clamping, effectively solve the problem of poor synchronism and uneven clamping force caused by clamping one by one in prior art, when operator rotates screw block, connecting rod drives stud rotation, stud drives threaded moving block movement, threaded moving block drives rack sliding in limiting block, rack drives gear rotation, gear drives bidirectional screw in connecting block rotation through connecting shaft, two clamping blocks on bidirectional screw move synchronously, form uniform clamping to the upper and lower flange plate of steel box girder body, since rack and gear at four lifting points are linked through unified transmission chain, ensure that four groups of bidirectional screw rotate synchronously with same speed and number of turns.

Description

Technical Field

[0001] This invention relates to the field of steel box girder hoisting technology, specifically to a hoisting tool and method for steel box girders of suspension bridges. Background Technology

[0002] The steel box girder for suspension bridges is a widely used stiffening girder structure in long-span suspension bridges. It typically employs a flat, streamlined, closed box-shaped cross-section, composed of a top plate, bottom plate, web, diaphragms, and longitudinal stiffening ribs. This structure offers significant advantages such as high torsional stiffness, light weight, low wind resistance, and high load-bearing efficiency, effectively resisting torsional deformation of suspension bridges under wind loads and eccentric loads. Steel box girders are usually manufactured in sections in a factory and connected as a whole by welding or high-strength bolts. They typically have internal maintenance access and ventilation systems, and require appropriate hoisting operations before use.

[0003] In existing hoisting techniques, a specialized lifting device is used to lift the steel box girder segment to be hoisted onto the girder and align it. The four connecting blocks under the lifting device are then aligned with the pre-set clamping positions on both sides of the steel box girder. Once all four clamping points have completed their actions and are confirmed to be locked in place, the lifting equipment slowly lifts the girder, using four-point force transmission to smoothly raise the steel box girder. After hoisting to the design position, coarse positioning and temporary connection are performed first. Then, the beam segment's posture is precisely adjusted to meet the docking accuracy through the fine-tuning mechanism on the lifting device. Finally, the clamping mechanism is reversed to disengage the connecting blocks from the steel box girder, and the lifting device is reset to complete one hoisting cycle.

[0004] However, during hoisting, the four clamping points need to be clamped one by one, which can lead to problems such as asynchronous clamping and inconsistent clamping force. This causes the steel box girder to undergo local elastic twisting or warping due to single-point eccentric loading before hoisting, disrupting the original straight posture of the beam. At the moment of hoisting, due to uneven force on each point, the beam will experience uncontrollable impact shaking and lateral swaying. In severe cases, it can cause plastic deformation or even slippage of the locally excessive clamps or threaded moving blocks. Furthermore, uneven clamping force can cause the beam to form a twisting effect during hoisting, which not only aggravates wind-induced vibration but also causes misalignment of the circumferential joint and inability to insert high-strength bolts due to inconsistent beam strain during placement and docking. Ultimately, this can lead to loss of hoisting accuracy and even safety accidents.

[0005] Although the above problems can be solved by synchronous limiters, during synchronous rotation, the moving block may get stuck on paint buildup or welding slag, and it does not actually compress the metal base material of the steel box girder. It cannot provide a warning operation after rotating to a certain position, making it impossible for operators to judge the true safety status, which ultimately leads to the forced interruption of hoisting or uncontrollable loss of beam control. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a lifting device and method for lifting steel box girders of suspension bridges. This lifting device for steel box girders of suspension bridges has the advantages of simultaneously limiting four clamping points and reminding users to clamp in place, thus solving the problems mentioned in the background art.

[0007] The present invention provides the following technical solution: a lifting device for steel box girder of suspension bridge, comprising a top plate and a lifting plate, wherein a limit indication mechanism is provided on the lifting plate; The limit indicator mechanism is equipped with a reminder component that converts rotational force into tactile force at its power input end, and a synchronization component that converts rotational force into meshing force at its other power output end. The reminder component includes a stud, a connecting rod, a screwing block, a cam, a roller, a connecting spring, and a guide telescopic rod; The synchronization component includes a connecting block, a bidirectional screw, a connecting shaft, a gear, a rack, and a limiting block; The limit indication mechanism consists of an alert component and a synchronization component.

[0008] Preferably, the outer surface of the stud is rotatably mounted to the inner wall of the hanging plate, one end of the connecting rod is fixedly mounted to one end of the stud, the left side of the screwing block is fixedly mounted to the other end of the connecting rod, the inside of the cam is fixedly mounted to the outer surface of the connecting rod, the outer surface of the roller is in contact with the outer surface of the cam, one end of the connecting spring is fixedly mounted to the bottom of the roller housing, and one end of the guide telescopic rod is fixedly mounted to the bottom of the roller housing.

[0009] Preferably, the back of the connecting block is fixedly installed with the front of the hanging plate, the outer surface of the bidirectional screw is rotatably installed with the inner wall of the connecting block, one end of the connecting shaft is fixedly installed with one end of the bidirectional screw, the inside of the gear is fixedly installed with the outer surface of the connecting shaft, the front of the rack meshes with the outer surface of the gear, the inside of the limiting block is slidably connected with the outer surface of the rack, and the lower surface of the limiting block is fixedly installed with the upper surface of the hanging plate.

[0010] Preferably, a fixing block is fixedly installed on the right side of the hanging plate, and the upper surface of the fixing block is fixedly installed to one end of the connecting spring and the guide telescopic rod.

[0011] Preferably, a trigger block is fixedly installed on the right side of the roller housing, and a trigger-type alarm bell is installed on the lower surface of the trigger block.

[0012] Preferably, the left side of the trigger-type alarm bell is fixedly installed on the right side of the hanging plate.

[0013] Preferably, a clamping block is threadedly installed on the outer surface of the bidirectional screw, and a steel box girder body is clamped and installed on the surface of the clamping block. A threaded moving block is fixedly installed on the upper surface of the rack, and the inner wall of the bottom end of the threaded moving block is threadedly installed with the outer surface of the stud.

[0014] Preferably, a limiting screw is installed on the inner wall thread of the connecting block, and the outer surface of the limiting screw is installed with the internal thread of the hanging plate.

[0015] Preferably, a suspension rope is fixedly installed on the upper surface of the top plate, and a hanging ring is fixedly installed at one end of the suspension rope.

[0016] Preferably, connecting ropes are fixedly installed around the lower surface of the top plate, and one end of each of the four sets of connecting ropes is fixedly installed to the upper surface of the hanging plate.

[0017] A method for hoisting a steel box girder of a suspension bridge, using the hoisting equipment for steel box girders of suspension bridges as described above, includes the following steps: S1: Lift the lifting equipment to the top of the main body of the steel box girder to be lifted and align it, so that the four connecting blocks under the lifting plate are aligned with the clamping positions on both sides of the main body of the steel box girder. S2: Slowly lower the lifting device so that the side of the main body of the steel box girder enters the gap between the two clamping blocks in each connecting block; S3: Rotate the screw block, which drives the stud to rotate through the connecting rod. The stud drives the threaded moving block to move, which in turn drives the rack to slide. The rack drives the gear to rotate, and the gear drives the bidirectional screw to rotate through the connecting shaft. This causes the two clamping blocks on the bidirectional screw to move synchronously towards each other, thus clamping the upper and lower flange plates of the steel box girder body. S4: Continue rotating the screwing block until the clamping block truly presses against the metal base material of the steel box girder. At this time, the connecting rod drives the cam to rotate to a specific angle, and the cam pushes the roller to the lowest point. The trigger block on the right side of the roller housing touches the trigger alarm bell to issue an alarm, indicating that the clamping has been truly in place. After confirming that all clamping points have issued alarms, the lifting equipment slowly lifts and smoothly raises the steel box girder body to the design position. S5: After completing the positioning and connection of the main body of the steel box girder, rotate the screw block in the opposite direction to drive the bidirectional screw to rotate in the opposite direction, so that the clamping blocks move synchronously in opposite directions and completely release the clamping of the main body of the steel box girder; lift the lifting device as a whole to complete one lifting cycle.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. This type of suspension bridge steel box girder hoisting device, through the setting of a synchronous component, achieves mechanical linkage clamping at four clamping points, effectively solving the problems of poor synchronization and uneven clamping force caused by individual clamping in existing technologies. When the operator rotates the screw block, the connecting rod drives the stud to rotate, the stud drives the threaded moving block to move, the threaded moving block drives the rack to slide within the limit block, the rack drives the gear to rotate, and the gear drives the bidirectional screw to rotate within the connecting block through the connecting shaft. The two clamping blocks on the bidirectional screw move synchronously towards each other, forming a uniform clamping force on the upper and lower flange plates of the steel box girder body. Uniform clamping, with racks and gears at the four lifting points linked by a unified transmission chain, ensures that the four sets of bidirectional screws rotate synchronously at the same speed and number of turns. This forces the four clamping blocks to contact the steel box girder body simultaneously with the same displacement and clamping force, completely avoiding elastic twisting and warping of the beam caused by single-point eccentric loading, as well as impact swaying and lateral swaying at the moment of lifting. It also avoids the risk of twisting effect and wind-induced vibration aggravation during the lifting process, ensuring that the misalignment of the circumferential joint meets the design requirements when the beam is positioned and connected, and that high-strength bolts can be smoothly inserted, thus improving the lifting accuracy and safety.

[0019] 2. This type of suspension bridge steel box girder hoisting device solves the problem of the moving block getting stuck on paint buildup or welding slag, creating a false pressure state and failing to promptly alert the operator, by setting a reminder component in the limit indicator mechanism. During the clamping process, the connecting rod drives the cam to rotate synchronously, and the cam pushes the roller that is in contact with its outer surface. The bottom of the roller's outer shell is equipped with a connecting spring and a guide telescopic rod, both of which are fixed to the fixed block. When the clamping block truly presses against the metal base material of the steel box girder, the clamping resistance increases, causing the operating torque to increase accordingly. The cam rotates to a specific angle and pushes the roller to the lowest point. The trigger block on the right side of the roller's outer shell then touches the trigger alarm bell to sound an audible reminder, informing the operator that the clamping has been properly secured. If the clamping block is only stuck on the paint or welding slag, the cam cannot reach the trigger position due to insufficient clamping resistance, and the trigger alarm bell will not sound. This effectively distinguishes between the two states of true clamping and false clamping. This mechanical feedback mechanism does not require electronic sensors, has high reliability, and enables operators to accurately judge the true safety status of each clamping point. It avoids major safety accidents such as sudden failure of clamping points, eccentric loading and tilting of beams, or even slippage and fall caused by the crushing of paint or welding slag, and ensures the smooth and continuous progress of hoisting operations. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the device of the present invention; Figure 2 For the present invention Figure 1 A top-view structural diagram; Figure 3 For the present invention Figure 1 A schematic diagram of the structure viewed from below; Figure 4For the present invention Figure 1 A schematic diagram of the cross-sectional structure; Figure 5 For the present invention Figure 4 Enlarged schematic diagram of the structure at point A; Figure 6 For the present invention Figure 4 Enlarged schematic diagram of the structure at point B.

[0021] In the diagram: 1. Top plate; 2. Suspension rope; 3. Hanging ring; 4. Connecting rope; 5. Suspended plate; 6. Reminder component; 601. Stud; 602. Connecting rod; 603. Tightening block; 604. Cam; 605. Roller; 606. Connecting spring; 607. Guide telescopic rod; 608. Trigger block; 609. Trigger-type alarm bell; 610. Fixing block; 7. Synchronization component; 701. Connecting block; 702. Bidirectional screw; 703. Connecting shaft; 704. Gear; 705. Rack; 706. Limit block; 707. Clamping block; 708. Threaded moving block; 709. Limit screw; 8. Steel box girder main body. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Please see Figure 1 , Figure 4 and Figure 5 A lifting device for a steel box girder of a suspension bridge includes a top plate 1 and a lifting plate 5. A limit indication mechanism is installed on the lifting plate 5. The top plate 1 is a rectangular flat plate structure with rounded corners to reduce stress concentration. The lifting plate 5 is a square flat plate arranged parallel to the top plate 1, with an area larger than that of the top plate 1 to ensure sufficient space for the clamping points below. The limit indicator mechanism is equipped with a reminder component 6 that converts rotational force into contact force at the power input end, and a synchronization component 7 that converts rotational force into engagement force at the other power output end of the limit indicator mechanism. The reminder component 6 includes a stud 601, a connecting rod 602, a tightening block 603, a cam 604, a roller 605, a connecting spring 606, and a guide telescopic rod 607. The stud 601 is a fully threaded cylindrical rod, its outer surface rotatably mounted to the inner wall of the hanging plate 5 via a rolling bearing or a copper-based sliding bushing to reduce frictional resistance. The connecting rod 602 is a cylindrical metal rod, one end of which is fixedly mounted to one end of the stud 601 by welding or integral molding. The tightening block 603 is a hexagonal or star-shaped manual operating component, its left center fixed to the other end of the connecting rod 602 via an internal hexagonal set screw. The cam 604 is a disc-shaped component with an eccentric arc profile, its internal center hole connecting to the connecting rod. The outer surface of 602 is fixedly installed by key connection or interference fit, so that cam 604 rotates synchronously with connecting rod 602; roller 605 is a cylindrical rolling body, whose outer surface is tangentially fitted with the outer surface of cam 604. Roller 605 is installed in U-shaped housing by pin and can rotate freely; connecting spring 606 is a cylindrical helical compression spring, one end of which is fixedly installed to the bottom of the housing of roller 605 by welding or slot; guide telescopic rod 607 is a multi-stage sleeve telescopic rod, one end of which is fixedly installed to the bottom of the housing of roller 605 by threaded connection. Guide telescopic rod 607 and connecting spring 606 are arranged in parallel, and their central axes are on the same straight line to ensure that roller 605 moves smoothly in the vertical direction.

[0024] The synchronization component 7 includes a connecting block 701, a bidirectional screw 702, a connecting shaft 703, a gear 704, a rack 705, and a limiting block 706. The connecting block 701 is a rectangular block component, its back side fixed to the front side of the hanging plate 5 by high-strength bolts or welding. The bidirectional screw 702 is a lead screw with two sections of opposite thread directions, its outer surface rotating with the internal threaded hole of the connecting block 701 via a trapezoidal or rectangular thread. The two ends of the bidirectional screw 702 are ferrules that engage with the bushings of the connecting block 701. The connecting shaft 703 is a solid cylindrical shaft, one end of which engages with one end of the bidirectional screw 702. The gear 704 is a spur gear, and its internal center hole is fixedly installed to the outer surface of the connecting shaft 703 by a flat key or spline. The gear 704 and the connecting shaft 703 are arranged coaxially. The rack 705 is a straight rack, and its front tooth surface meshes with the outer surface of the gear 704. The back of the rack 705 is a flat surface. The limiting block 706 is a rectangular guide block, and its interior has a T-shaped or rectangular sliding groove. The outer surface of the rack 705 is in sliding fit with the inner wall of the sliding groove of the limiting block 706. The lower surface of the limiting block 706 is fixedly installed to the upper surface of the hanging plate 5 by welding or bolts.

[0025] The limit indication mechanism consists of an indication component 6 and a synchronization component 7. The outer surface of the stud 601 is rotatably mounted to the inner wall of the hanging plate 5. One end of the connecting rod 602 is fixedly mounted to one end of the stud 601. The left side of the turning block 603 is fixedly mounted to the other end of the connecting rod 602. The inside of the cam 604 is fixedly mounted to the outer surface of the connecting rod 602. The outer surface of the roller 605 is in contact with the outer surface of the cam 604. One end of the connecting spring 606 is fixedly mounted to the bottom of the outer shell of the roller 605. One end of the guide telescopic rod 607 is fixedly mounted to the bottom of the outer shell of the roller 605. A fixing block 610 is fixedly mounted on the right side of the hanging plate 5. The upper surface of the fixing block 610 is fixedly mounted to one end of the connecting spring 606 and the guide telescopic rod 607. A trigger block 608 is fixedly mounted on the right side of the outer shell of the roller 605. A trigger-type alarm bell 609 is installed on the lower surface of the trigger block 608. The left side of the trigger-type alarm bell 609 is fixedly mounted to the right side of the hanging plate 5.

[0026] Specifically, by setting up the reminder component 6, the external turning force is converted into the rotational motion of the cam 604 using the stud 601 and connecting rod 602. The cam 604, in conjunction with the roller 605, converts the rotational motion into a linear contact force, driving the trigger block 608 to move down and touch the trigger alarm bell 609. This triggers an audible alarm when the steel box girder is hoisted into place or about to reach the limit position, allowing operators to be promptly informed of the hoisting position status. This effectively avoids safety hazards caused by over-limit hoisting or failure to reach the limit position, improving the safety and controllability of the hoisting operation. By setting up the connecting spring 606 and the guide telescopic rod 607, on the one hand, the connecting spring 606 provides elastic restoring force to the roller 605, ensuring that the cam 604 continuously maintains contact with the outer surface of the roller 605, preventing transmission failure due to vibration or gaps; on the other hand, the guide telescopic rod 607 guides and limits the movement trajectory of the roller 605, ensuring that the trigger block 608 moves accurately in the predetermined direction, improving the reliability and repeatability of the triggering action.

[0027] Please see Figure 1 , Figure 4 and Figure 6The back of the connecting block 701 is fixedly installed with the front of the hanging plate 5. The outer surface of the bidirectional screw 702 is rotatably installed with the inner wall of the connecting block 701. One end of the connecting shaft 703 is fixedly installed with one end of the bidirectional screw 702. The inside of the gear 704 is fixedly installed with the outer surface of the connecting shaft 703. The front of the rack 705 meshes with the outer surface of the gear 704. The inside of the limiting block 706 is slidably connected with the outer surface of the rack 705. The lower surface of the limiting block 706 is fixedly installed with the upper surface of the hanging plate 5. The outer surface of the bidirectional screw 702 is threaded with a clamping block 707. The surface of the clamping block 707 is clamped and installed with a steel box beam body 8. The upper surface of the rack 705 is fixedly installed with a threaded moving block 708. The inner wall of the bottom end of the threaded moving block 708 is threadedly installed with the outer surface of the stud 601. The inner wall of the connecting block 701 is threaded with a limiting screw 709. The outer surface of the limiting screw 709 is threaded with the inner surface of the hanging plate 5.

[0028] Specifically, by setting up a synchronization component 7, the rotational motion of the bidirectional screw 702 is transmitted to the gear 704 via the connecting shaft 703. The gear 704 meshes with the rack 705 to convert the rotational motion into linear motion, thereby driving the clamping block 707 to move in opposite directions or away from each other along the bidirectional screw 702. This achieves automatic clamping and releasing of the steel box girder body 8, enabling the lifting device to firmly grip the steel box girder body 8 during the lifting process. This effectively prevents the steel box girder body 8 from falling off due to lifting vibration or wind, thus improving the safety and reliability of the lifting operation. By setting the threaded moving block 708 to be threadedly installed with the stud 601, the rotational movement of the stud 601 in the reminder component 6 is synchronously transmitted to the rack 705, so that the power input end of the reminder component 6 and the power output end of the synchronization component 7 form a mechanical linkage. That is, when the operator turns the turning block 603 to drive the stud 601 to rotate, not only is the trigger alarm bell 609 triggered to issue a limit alarm prompt, but the threaded moving block 708 also drives the rack 705 to move, thereby driving the clamping block 707 to move. This achieves synchronous linkage between alarm prompt and clamping lock, avoiding the safety hazards caused by the asynchronous prompt and action, and greatly improving the overall coordination and safety of hoisting operations.

[0029] Please see Figure 1 , Figure 2 , Figure 3 and Figure 4 A suspension rope 2 is fixedly installed on the upper surface of the top plate 1. The suspension rope 2 is a high-strength steel wire rope or synthetic fiber rope. Its lower end is fixed in the lifting lug on the upper surface of the top plate 1 by compression sleeve or casting. A hanging ring 3 is fixedly installed on one end of the suspension rope 2. The hanging ring 3 is a circular or elliptical forged lifting ring. It is fixedly connected to the upper end of the suspension rope 2 by ring pressing or braiding. Connecting ropes 4 are fixedly installed on all four sides of the lower surface of the top plate 1. One end of each of the four sets of connecting ropes 4 is fixedly installed on the upper surface of the suspension plate 5. The four sets of connecting ropes 4 are symmetrically distributed, and the included angle between adjacent connecting ropes 4 is 90 degrees.

[0030] Specifically, by setting up lifting ropes 2 and hanging rings 3, the lifting ropes 2 are fixedly installed on the upper surface of the top plate 1, and the hanging rings 3 serve as a standard lifting interface connected to the hook of the lifting equipment. The structure is simple and reliable, and the force transmission path during lifting is clear and direct. That is, the lifting force of the lifting equipment is transmitted to the top plate 1 sequentially through the hanging rings 3 and the lifting ropes 2, and then evenly distributed to the connecting ropes 4 below through the top plate 1. This ensures the effective transmission and even distribution of the lifting force and avoids the risk of structural damage caused by local stress concentration. By setting up four sets of connecting ropes 4 evenly distributed around the lower surface of the top plate 1, and fixing the other end of each of the four sets of connecting ropes 4 to the upper surface of the hanging plate 5, a stable support structure with four-point suspension is formed. This ensures that the hanging plate 5 remains horizontally balanced during the lifting process, effectively preventing the tilting and swaying of the hanging plate 5 caused by single-point or two-point suspension. This ensures the stability of the steel box girder body 8 during lifting, transportation, and positioning, and significantly improves the stability and safety of the lifting operation.

[0031] Working principle: During use, the hook of the lifting equipment is connected to the hanging ring 3 above the top plate 1. The entire lifting device is lifted to the top of the steel box girder body 8 to be lifted via the lifting rope 2 and four sets of connecting ropes 4. The position of the lifting device is adjusted so that the four connecting blocks 701 below the lifting plate 5 are aligned with the pre-set clamping positions on both sides of the steel box girder body 8. Then, the lifting device is slowly lowered so that the side of the steel box girder body 8 enters the gap between the two clamping blocks 707 in each connecting block 701. The operator rotates the turning block 603, which drives the connecting rod 602 to rotate. The connecting rod 602 drives the stud 601 to rotate. The stud 601 drives the threaded moving block 708, which is threadedly installed with it, to move axially along the stud 601. The threaded moving block 708 is fixedly installed on the upper surface of the rack 705, so the rack 705 moves synchronously. The rack 705 maintains linear motion under the guidance of the limiting block 706 and drives the gear 704 meshing with it to rotate. Gear 704 drives bidirectional screw 702 to rotate within connecting block 701 via connecting shaft 703. The two clamping blocks 707 on bidirectional screw 702 then move synchronously towards or away from each other, thus clamping and limiting the upper and lower flanges of the steel box girder body 8. During clamping, connecting rod 602 simultaneously drives cam 604 to rotate. Cam 604 pushes roller 605, which is in contact with its outer surface. A connecting spring 606 and a guide telescopic rod 607 are installed at the bottom of the roller 605's outer shell, both fixed to the fixing block 610. As cam 604 rotates, roller 605 is periodically lifted or released. When bidirectional screw 702 drives clamping block 707 to the position where it truly presses against the metal base material of the steel box girder body 8, the clamping resistance reaches a preset value. The rotational torque applied by the operator increases accordingly, and cam 604 rotates precisely to a specific angle, pushing roller 605 to its lowest point. The trigger block 608, fixedly mounted on the right side of the roller 605 housing, descends and touches the trigger alarm bell 609. The trigger alarm bell 609 sounds, informing the operator that the clamping block 707 is truly clamped in place, rather than being a false clamping due to paint or welding slag. The connecting spring 606 and the guide telescopic rod 607 ensure that the roller 605 can return to its original position and maintain continuous contact with the cam 604. After the clamping indication is given, the operator confirms that all clamping points are truly locked. Subsequently, the lifting equipment slowly lifts the steel box girder body 8 through the four connection points. Due to the synchronous clamping at four points and the uniform clamping force, the beam will not twist, sway, or tilt during the lifting process. After the steel box girder body 8 is lifted above the design position, rough positioning and temporary connection are performed.If fine-tuning of the beam segment's posture is required to meet docking accuracy, the operator can slightly loosen the clamping block 707 by reversing the fine-tuning block 603. This, combined with the lifting equipment, allows for posture adjustment until the alignment accuracy of the circumferential joint between the main body 8 of the steel box girder and the adjacent beam segment meets the requirements for welding or bolted connection. After the main body 8 of the steel box girder is finally fixed, the reversing screw block 603 is rotated, driving the bidirectional screw 702 to rotate in the opposite direction via the synchronous component 7. This causes the clamping blocks 707 to move synchronously in opposite directions, completely releasing their grip on the main body 8 of the steel box girder. Simultaneously, during the reverse rotation, the trigger block 608 disengages from the trigger-type alarm bell 609, stopping the alarm. Finally, the lifting equipment lifts the entire lifting device away, completing one full lifting cycle.

[0032] The trigger-type alarm bell 609, specifically used in the lifting equipment for the steel box girder of this suspension bridge, adopts a mechanical impact bell structure. Its components include a hollow copper bell body, a built-in metal hammer, and a return spring. It does not contain any electronic components. The top plate 1, lifting plate 5, connecting rope 4, and lifting rope 2 should be made of high-strength alloy structural steel to withstand the heavy loads during the lifting of the steel box girder of the long-span suspension bridge and possess good low-temperature toughness. The bidirectional screw 702 and clamping block 707 are recommended to be made of 42CrMo material and... For heat treatment, the threaded surface needs to be quenched to improve wear resistance and prevent thread wear or plastic deformation caused by repeated clamping; gear 704 and rack 705 should be made of 20CrMnTi and carburized and quenched to ensure high hardness and fatigue resistance of the meshing surface. At the same time, the sliding contact surface between rack 705 and limit block 706 should be inlaid with copper alloy liner or treated with wear-resistant coating to reduce friction; it is recommended that cam 604 and roller 605 in the reminder component 6 be made of GCr15 bearing steel and quenched to HRC 60-62; trigger block 608 and trigger alarm bell 609 can be made of brass or cast copper, which have a crisp impact sound and are corrosion resistant; connecting spring 606 should be made of 50CrVA oil-quenched spring steel wire; the surface of guide telescopic rod 607 needs to be plated with hard chrome for rust prevention; fixing block 610 can be made of ordinary carbon structural steel and welded to the side of hanging plate 5.

[0033] Before each hoisting operation, it is essential to check whether the gears 704 and racks 705 in the four sets of synchronization components 7 are meshing properly. Sufficient extreme pressure lithium-based grease should be applied to the sliding surface inside the limit block 706, and any welding slag or dust should be cleaned to prevent jamming and synchronization failure. It is strictly forbidden to forcibly lift the machine before all the trigger alarm bells 609 have sounded to prevent false clamping and slippage of the main body 8 of the steel box girder. Before lifting, it is also necessary to visually confirm that all limit screws 709 are tightened to prevent the connecting block 701 from loosening relative to the lifting plate 5. If abnormal impact is found between the cam 604 and the roller 605 during the hoisting process, it should be disassembled and inspected in time and lubricated. Severely worn cams 604 or rollers 605 should be replaced immediately. After each use, the exposed threads of the bidirectional screw 702 should be cleaned and coated with anti-rust oil. When not in use for a long time, the clamping block 707 should be adjusted to the loosened state to release the preload of the bidirectional screw 702 and avoid permanent creep deformation of the threads.

[0034] A method for hoisting a steel box girder of a suspension bridge, using the hoisting equipment for steel box girders of suspension bridges as described above, includes the following steps: S1: Lift the lifting equipment to the top of the main body 8 of the steel box girder to be lifted and align it, so that the four connecting blocks 701 under the lifting plate 5 are respectively aligned with the clamping positions on both sides of the main body 8 of the steel box girder. S2: Slowly lower the lifting device so that the side of the main body 8 of the steel box girder enters the gap between the two clamping blocks 707 in each connecting block 701; S3: Rotating the screw block 603 causes the stud 601 to rotate via the connecting rod 602. The stud 601 drives the threaded moving block 708 to move, which in turn drives the rack 705 to slide. The rack 705 drives the gear 704 to rotate. The gear 704 drives the bidirectional screw 702 to rotate via the connecting shaft 703, causing the two clamping blocks 707 on the bidirectional screw 702 to move synchronously towards each other, thus clamping the upper and lower flange plates of the steel box girder body 8. S4: Continue to rotate the screwing block 603 until the clamping block 707 truly presses the metal base material of the steel box girder body 8. At this time, the connecting rod 602 drives the cam 604 to rotate to a specific angle. The cam 604 pushes the roller 605 to the lowest point. The trigger block 608 on the right side of the roller 605 housing touches the trigger alarm bell 609 to issue an alarm, indicating that the clamping has been truly in place. After confirming that all clamping points have issued alarms, the lifting equipment slowly lifts and smoothly raises the steel box girder body 8 to the design position. S5: After completing the positioning and connection of the main body 8 of the steel box girder, rotate the screw block 603 in the opposite direction to drive the bidirectional screw 702 to rotate in the opposite direction, so that the clamping block 707 moves synchronously in opposite directions and completely releases the clamping of the main body 8 of the steel box girder; lift the lifting device as a whole to complete one lifting cycle.

[0035] It should be noted that the scope of protection of this invention does not involve improvements to the internal structure and methods; furthermore, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0036] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A lifting device for steel box girders of suspension bridges, characterized in that: It includes a top plate (1) and a hanging plate (5), wherein a limit indicator mechanism is installed on the hanging plate (5); The power input end of the limit indicator mechanism is equipped with a reminder component (6) that converts rotational force into tactile force, and the other end of the power output of the limit indicator mechanism is equipped with a synchronization component (7) that converts rotational force into meshing force. The reminder component (6) includes a stud (601), a connecting rod (602), a screw block (603), a cam (604), a roller (605), a connecting spring (606), and a guide telescopic rod (607). The synchronization component (7) includes a connecting block (701), a bidirectional screw (702), a connecting shaft (703), a gear (704), a rack (705), and a limiting block (706). The limit indication mechanism consists of an indication component (6) and a synchronization component (7).

2. The lifting device for a steel box girder of a suspension bridge according to claim 1, characterized in that: The outer surface of the stud (601) is rotatably mounted to the inner wall of the hanging plate (5), one end of the connecting rod (602) is fixedly mounted to one end of the stud (601), the left side of the screwing block (603) is fixedly mounted to the other end of the connecting rod (602), the inside of the cam (604) is fixedly mounted to the outer surface of the connecting rod (602), the outer surface of the roller (605) is in contact with the outer surface of the cam (604), one end of the connecting spring (606) is fixedly mounted to the bottom of the outer shell of the roller (605), and one end of the guide telescopic rod (607) is fixedly mounted to the bottom of the outer shell of the roller (605).

3. The lifting device for a steel box girder of a suspension bridge according to claim 1, characterized in that: The back of the connecting block (701) is fixedly installed with the front of the hanging plate (5). The outer surface of the bidirectional screw (702) is rotatably installed with the inner wall of the connecting block (701). One end of the connecting shaft (703) is fixedly installed with one end of the bidirectional screw (702). The inside of the gear (704) is fixedly installed with the outer surface of the connecting shaft (703). The front of the rack (705) meshes with the outer surface of the gear (704). The inside of the limiting block (706) is slidably connected with the outer surface of the rack (705). The lower surface of the limiting block (706) is fixedly installed with the upper surface of the hanging plate (5).

4. The lifting device for a steel box girder of a suspension bridge according to claim 2, characterized in that: A fixing block (610) is fixedly installed on the right side of the hanging plate (5), and the upper surface of the fixing block (610) is fixedly installed with one end of the connecting spring (606) and the guide telescopic rod (607).

5. The lifting device for a steel box girder of a suspension bridge according to claim 2, characterized in that: A trigger block (608) is fixedly installed on the right side of the outer shell of the roller (605). A trigger alarm bell (609) is installed on the lower surface of the trigger block (608). The left side of the trigger alarm bell (609) is fixedly installed on the right side of the hanging plate (5).

6. The lifting device for a steel box girder of a suspension bridge according to claim 3, characterized in that: The outer surface of the bidirectional screw (702) is threaded with a clamping block (707), and the surface of the clamping block (707) is clamped with a steel box girder body (8). The upper surface of the rack (705) is fixedly installed with a threaded moving block (708), and the bottom inner wall of the threaded moving block (708) is threaded with the outer surface of the stud (601).

7. The lifting device for a steel box girder of a suspension bridge according to claim 3, characterized in that: The inner wall of the connecting block (701) is threaded with a limiting screw (709), and the outer surface of the limiting screw (709) is threaded with the inner thread of the hanging plate (5).

8. The lifting device for a steel box girder of a suspension bridge according to claim 1, characterized in that: A suspension rope (2) is fixedly installed on the upper surface of the top plate (1), and a hanging ring (3) is fixedly installed at one end of the suspension rope (2).

9. The lifting device for a steel box girder of a suspension bridge according to claim 1, characterized in that: Connecting ropes (4) are fixedly installed around the lower surface of the top plate (1), and one end of each of the four sets of connecting ropes (4) is fixedly installed to the upper surface of the hanging plate (5).

10. A method for hoisting a steel box girder of a suspension bridge, comprising using the hoisting equipment for steel box girders of suspension bridges as described in any one of claims 1 to 10, characterized in that, Includes the following steps: S1: Lift the lifting equipment to the top of the main body (8) of the steel box girder to be lifted and align it so that the four connecting blocks (701) under the lifting plate (5) are aligned with the clamping positions on both sides of the main body (8) of the steel box girder. S2: Slowly lower the lifting device so that the side of the main body of the steel box girder (8) enters the gap between the two clamping blocks (707) in each connecting block (701); S3: Rotate the screwing block (603), which drives the stud (601) to rotate through the connecting rod (602). The stud (601) drives the threaded moving block (708) to move, which in turn drives the rack (705) to slide. The rack (705) drives the gear (704) to rotate. The gear (704) drives the bidirectional screw (702) to rotate through the connecting shaft (703), so that the two clamping blocks (707) on the bidirectional screw (702) move synchronously towards each other, forming a clamp on the upper and lower flange plates of the main body of the steel box girder (8). S4: Continue to rotate the screwing block (603) until the clamping block (707) truly presses the metal base of the steel box girder body (8). At this time, the connecting rod (602) drives the cam (604) to rotate to a specific angle. The cam (604) pushes the roller (605) to the lowest point. The trigger block (608) on the right side of the roller (605) housing touches the trigger alarm bell (609) to issue an alarm, indicating that the clamping has been truly in place. After confirming that all clamping points have issued alarms, the lifting equipment slowly lifts and smoothly raises the steel box girder body (8) to the design position. S5: After completing the positioning and connection of the main body (8) of the steel box girder, rotate the screw block (603) in the opposite direction to drive the bidirectional screw (702) to rotate in the opposite direction, so that the clamping block (707) moves synchronously in opposite directions and completely releases the clamping of the main body (8) of the steel box girder; lift the lifting device as a whole to complete one lifting cycle.

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