A retractable construction trestle main beam lifting mechanism

Abstract

This invention belongs to the field of bridge engineering technology, specifically disclosing a retractable construction trestle main beam lifting mechanism, including a main bridge frame and two retractable bridge frames. Main beams are provided at both ends of the bottom of the main bridge frame. The two main beams are connected to the two retractable bridge frames respectively via a retractable mechanism on their outer sides. Two lifting hydraulic cylinders are symmetrically arranged on both sides of the bottom of the two main beams. Dustproof and moisture-proof components are provided on the exterior of the two lifting hydraulic cylinders on the same side. Support columns are provided at both ends of the exterior of the two main beams. A connecting shaft is rotatably inserted into one end of each support column. A rotating seat is sleeved on the outside of the connecting shaft. An adjusting hydraulic cylinder is fixedly installed on the outside of the rotating seat. This invention transfers part of the vertical load through a suspension reinforcement structure, reducing the load-bearing pressure of the lifting hydraulic cylinders. Simultaneously, a multi-layer labyrinth seal effectively isolates moisture and mud, ensuring the stable and reliable lifting of the trestle in harsh construction environments.

Description

Technical Field

[0001] This invention belongs to the field of bridge engineering technology, and specifically discloses a telescopic construction trestle main beam lifting mechanism. Background Technology

[0002] In tunnel excavation or open-cut foundation pit construction, retractable steel trestle bridges with lifting functions are often laid to facilitate the passage of transport trolleys and other vehicles on the surface of the construction trestle. A hydraulic lifting mechanism is installed under the main beam of the trestle bridge to adjust the bridge deck elevation to accommodate ground undulations or settlement of the support system at different construction stages. However, the following technical problems have been found in practical applications: The existing trestle bridge's vertical loads (structural self-weight, construction live load, and dynamic load from the transfer trolley) are almost entirely borne by the hydraulic lifting system beneath the main beam. Even after the lifting mechanism has been adjusted to the correct height and mechanically locked, the hydraulic cylinders and columns remain under high pressure for extended periods. Under construction dynamic loads, vibrations, or continuous settlement of the supporting foundation, the hydraulic cylinder seals are prone to fatigue leakage, causing additional settlement in the columns and leading to bridge deck instability. Especially when the transfer trolley moves frequently, the impact load exacerbates the damage to the underlying hydraulic system, making maintenance difficult and impacting the construction schedule. The interior of foundation pits or tunnels is often damp, containing stagnant water, mud, sprayed curing water, and construction dust. The piston rod expansion joint (dynamic seal) of the hydraulic cylinder beneath the main beam is exposed for extended periods. During lifting and lowering, water film and sediment are easily drawn into the cylinder, leading to hydraulic oil emulsification, cylinder corrosion, and seal failure. Conventional dust seals are insufficient to withstand repeated expansion and contraction, as well as the capillary action in humid environments. Once the seal fails, the lifting mechanism cannot maintain pressure, causing the bridge deck to tilt or even collapse, seriously threatening the safety of the transport trolley and construction personnel.

[0003] Therefore, there is an urgent need for a retractable construction trestle main beam lifting mechanism that can reduce the burden on the lower hydraulic cylinder by reinforcing it from above, effectively seal the hydraulic cylinder telescopic joint, and not affect construction or the passage of trolleys. Summary of the Invention

[0004] The purpose of this invention is to solve the problems existing in the background art, and to propose a telescopic construction trestle main beam lifting mechanism, including a main bridge frame and two telescopic bridge frames. Main beams are provided at both ends of the bottom of the main bridge frame. The two main beams are connected to the two telescopic bridge frames respectively through telescopic mechanisms on their outer sides, with two lifting hydraulic cylinders symmetrically arranged on both sides of the bottom of each of the two main beams. Dustproof and moisture-proof components are provided on the exterior of the two lifting hydraulic cylinders on the same side. Support columns are provided at both ends of the exterior of each of the two main beams. A connecting shaft is rotatably inserted into one end of each support column. A rotating seat is sleeved on the exterior of the connecting shaft. An adjusting hydraulic cylinder is fixedly installed on the exterior of the rotating seat. A tensioning shell is connected to the telescopic end of the adjusting hydraulic cylinder through a multi-section connecting mechanism. Screws are threaded through both ends of the tensioning shell, and hooks are provided at the outer ends of the two screws that are far apart from each other.

[0005] Preferably, the telescopic mechanism includes two telescopic hydraulic cylinders, which are respectively disposed on one side of the main beam. A base is fixedly disposed at the bottom of the telescopic bridge frame, and a load-bearing beam is disposed at the bottom of the telescopic bridge frame and in the middle of the base. The telescopic ends of the two telescopic hydraulic cylinders are connected to the outside of the load-bearing beam. A reinforcing compensation shell is disposed above the main bridge frame, and a compensation plate is slidably connected inside the reinforcing compensation shell. One bottom side of the compensation plate is fixedly connected to the upper surface of the telescopic bridge frame.

[0006] Preferably, the dustproof and moisture-proof component includes a first sealing shell and a second sealing shell, wherein the edge of the first sealing shell extends outward to form an external sealing frame, and the edge of the second sealing shell is embedded in the external sealing frame.

[0007] Preferably, a telescopic bellows is provided above both the first and second sealing shells. Multiple inner plates are provided on the inner wall of the telescopic bellows inside the first sealing shell, and multiple insert plates are provided on the inner wall of the second sealing shell. The insert plates and inner plates are equidistantly arranged from top to bottom along the inner wall of the telescopic bellows. Each insert plate has slots at both ends to accommodate the telescopic movement of the lifting hydraulic cylinder's telescopic joint. Each insert plate also has grooves for insertion into the inner plates. The first and second sealing shells are connected on both sides by symmetrically installed double-headed bolts. The inner edges of the telescopic bellows above the first and second sealing shells are connected by externally coated adhesive. The top of the telescopic bellows is sealed to the bottom of the main beam.

[0008] Preferably, the multi-section connecting mechanism includes a U-shaped seat, a ball joint is provided inside the U-shaped seat, the telescopic end of the adjusting hydraulic cylinder is connected to the ball joint, and a pressure seat is fixedly connected to one side of the outside of the U-shaped seat.

[0009] Preferably, both ends of the pressure seat are provided with rotating sleeves, and a shaft is rotatably inserted between the two rotating sleeves. A connecting seat is rotatably sleeved on the outside of the shaft. A reinforcing shaft seat is fixedly installed on one side of the connecting seat. The reinforcing shaft seat is connected to the inside of the tensioning shell through an internally provided rotating component.

[0010] Preferably, the rotating component includes a swivel joint, one end of which is connected to the interior of the tensioning shell, and the other end of which is rotatably connected to the interior of the reinforcing shaft seat.

[0011] Preferably, each of the lifting hydraulic cylinders is equipped with a pressure sensor, the outer surface of the telescopic corrugated pipe is processed with a hydrophobic layer, and both ends of the bottom of the main bridge frame and the side close to the main beam are equipped with sliding beams, with a sleeve slidably connected below the sliding beams.

[0012] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention forms a suspended reinforcement structure above the trestle bridge by setting support columns, adjusting hydraulic cylinders, tension shells, and hooks at both ends of the main beam. The adjusting hydraulic cylinders can drive the hooks to hook onto the top of the tunnel or other external support structures. By adjusting the tension force through the screw, part of the vertical load is transferred to the external support system, thereby significantly reducing the long-term load pressure on the lower lifting hydraulic cylinders, avoiding fatigue leakage of the lifting hydraulic cylinders due to long-term high-pressure loads, reducing the risk of additional settlement, and greatly improving the elevation stability of the trestle bridge under construction dynamic loads, vibrations, and foundation settlement conditions.

[0013] 2. This invention employs a dustproof and moisture-proof assembly consisting of a first sealing shell, a second sealing shell, and a telescopic bellows. The edge of the first sealing shell extends outward to form an external sealing frame, and the edge of the second sealing shell is embedded within this sealing frame, forming a reliable shell seal. Simultaneously, insert plates and inner plates are evenly spaced from top to bottom on the inner wall of the telescopic bellows. The insert plates have grooves that interlock with the inner plates, and also have slots to accommodate the telescopic movement of the lifting hydraulic cylinder, forming a multi-stage labyrinth seal structure. This design not only accommodates the telescopic movement of the lifting hydraulic cylinder but also effectively prevents external water films, mud, and dust from entering the cylinder, preventing hydraulic oil emulsification and cylinder corrosion, and ensuring the long-term reliable pressure-holding capacity of the lifting mechanism in humid and harsh environments.

[0014] 3. This invention features a reinforced compensation shell above the main bridge frame, with a compensation plate slidably connected inside. One bottom side of the compensation plate is fixedly connected to the upper surface of the telescopic bridge frame. When the telescopic hydraulic cylinder drives the telescopic bridge frame to extend outward, the compensation plate simultaneously slides out from the reinforced compensation shell, always covering the telescopic bridge frame, forming a continuous bridge deck support and reinforced compensation structure. This prevents sudden changes in bridge deck stiffness or flexural deformation due to telescopic movement, ensuring the smoothness and safety of the transfer trolley when traveling on the telescopic section.

[0015] 4. This invention incorporates a multi-section connecting mechanism between the adjusting hydraulic cylinder and the tensioning shell, including a ball joint, a U-shaped seat, a pressure seat, a rotating sleeve, a insert shaft, a connecting seat, a reinforcing shaft seat, and a swivel joint. This mechanism allows for multiple degrees of freedom of rotation and angle adjustment, enabling the hook to flexibly adjust its posture according to the actual position of the tunnel top or support point. This ensures that the suspension force is always transmitted in the optimal direction, avoiding additional bending moments or eccentric loads, and further enhancing the adaptability and stability of the suspension reinforcement system. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is another schematic diagram of the overall structure of the present invention; Figure 3 This is a schematic diagram of a partial connection structure between the telescopic cable tray and the telescopic mechanism of the present invention; Figure 4 This is a schematic diagram of a partial connection structure between the first sealing shell and the second sealing shell of the present invention; Figure 5 This is a schematic diagram showing the connection structure between the first sealing shell and the outer sealing frame of the present invention. Figure 6 This is a schematic diagram of the connection structure between the insert plate and the inner plate of the present invention; Figure 7 This is a schematic diagram of the connection structure between the main beam and the multi-section connection mechanism of the present invention; Figure 8 For the present invention Figure 4 Enlarged structural diagram at point A in the middle.

[0017] In the diagram: 1. Main cable tray; 2. Telescopic cable tray; 3. Reinforcing compensation shell; 4. Adjusting hydraulic cylinder; 5. Tensioning shell; 6. Hook; 7. Main beam; 8. Sleeve; 9. First sealing shell; 10. Load-bearing beam; 11. Sliding beam; 12. Second sealing shell; 13. Telescopic bellows; 14. Support column; 15. Telescopic hydraulic cylinder; 16. Compensation plate; 17. Insert plate; 18. Inner plate; 19. Insert shaft; 20. Pressure sensor; 21. Lifting hydraulic cylinder; 22. Rotating seat; 23. Rotary joint; 24. Ball joint; 25. U-shaped seat; 26. Rotating sleeve; 27. Connecting seat; 28. Pressing seat; 29. ​​Connecting shaft; 30. Embedded groove; 31. Outer sealing frame; 32. Reinforcing shaft seat; 33. Screw; 34. Groove; 35. Base; 36. Double-ended bolt fastener. Detailed Implementation

[0018] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] Numerous specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the invention is not limited to the specific embodiments disclosed below.

[0020] like Figures 1-8 The telescopic construction trestle main beam lifting mechanism shown includes a main bridge frame 1 and two telescopic bridge frames 2. Main beams 7 are provided at both ends of the bottom of the main bridge frame 1. The two main beams 7 are connected to the two telescopic bridge frames 2 respectively through telescopic mechanisms on their respective outer sides. Two lifting hydraulic cylinders 21 are symmetrically arranged on both sides of the bottom of the two main beams 7. Dustproof and moisture-proof components are provided on the exterior of the two lifting hydraulic cylinders 21 on the same side. Support columns 14 are provided at both ends of the exterior of the two main beams 7. A connecting shaft 29 is rotatably inserted into one end of the support column 14. A rotating seat 22 is sleeved on the exterior of the connecting shaft 29. An adjusting hydraulic cylinder 4 is fixedly installed on the exterior of the rotating seat 22. A tensioning shell 5 is connected to the telescopic end of the adjusting hydraulic cylinder 4 through a multi-section connecting mechanism. Screws 33 are threaded through both ends of the tensioning shell 5. Hooks 6 are provided at the ends of the two screws 33 that are far apart from each other.

[0021] like Figure 1 and Figure 2 As shown, during operation, the piston rod of the lifting hydraulic cylinder 21 extends or retracts synchronously, pushing the main beam 7 and the main bridge frame 1 to rise or fall as a whole, thereby achieving precise adjustment of the bridge deck elevation to adapt to ground undulations or support system settlement at different stages of tunnel excavation or foundation pit construction.

[0022] The telescopic mechanism includes two telescopic hydraulic cylinders 15, which are respectively set on one side of the outside of the main beam 7. A base 35 is fixedly set at the bottom of the telescopic bridge 2. A load-bearing beam 10 is set at the bottom of the telescopic bridge 2 and in the middle of the base 35. The telescopic ends of the two telescopic hydraulic cylinders 15 are connected to the outside of the load-bearing beam 10. A reinforcing compensation shell 3 is set on the top of the main bridge 1. A compensation plate 16 is slidably connected inside the reinforcing compensation shell 3. One bottom side of the compensation plate 16 is fixedly connected to the upper surface of the telescopic bridge 2.

[0023] like Figure 2 and Figure 3 As shown, when the length of the trestle needs to be adjusted, the telescopic hydraulic cylinder 15 drives the load-bearing beam 10 and the entire telescopic bridge frame 2 to move away from or closer to the main bridge frame 1. To ensure the rigidity and continuity of the bridge deck in the telescopic section, a reinforcing compensation shell 3 is installed above the main bridge frame 1. A compensation plate 16 is slidably connected inside the reinforcing compensation shell 3, and one bottom side of the compensation plate 16 is fixedly connected to the upper surface of the telescopic bridge frame 2. When the telescopic bridge frame 2 extends outward, the compensation plate 16 slides out synchronously from the reinforcing compensation shell 3, always covering the top of the telescopic bridge frame 2, forming a seamless bridge deck support, effectively avoiding bridge deck deflection or sudden stiffness changes caused by expansion and contraction, and ensuring the smooth movement of the transfer trolley.

[0024] The dustproof and moisture-proof component includes a first sealing shell 9 and a second sealing shell 12. The edge of the first sealing shell 9 extends outward to form an external sealing frame 31, and the edge of the second sealing shell 12 is embedded in the external sealing frame 31. A telescopic bellows 13 is provided above both the first sealing shell 9 and the second sealing shell 12. Multiple inner plates 18 are provided on the inner wall of the telescopic bellows 13 located inside the first sealing shell 9, and multiple insert plates 17 are provided on the inner wall of the second sealing shell 12. The multiple insert plates 17 and multiple inner plates 18 extend along the inner wall of the telescopic bellows 13. The plates are evenly spaced from top to bottom, and both ends of the plates 17 have slots 34 that move with the telescopic joints of the lifting hydraulic cylinder 21. The plates 17 also have slots 30 that are inserted into the plates 18. The first sealing shell 9 and the second sealing shell 12 are connected on both sides by symmetrically installed double-headed bolt fasteners 36. The inner edges of the telescopic bellows 13 located above the first sealing shell 9 and the second sealing shell 12 are connected by externally coated glue, and the top of the telescopic bellows 13 is sealed to the bottom of the main beam 7.

[0025] like Figures 3-6 As shown, when the lifting hydraulic cylinder 21 extends or retracts, the telescopic bellows 13 extends or retracts accordingly. The inner plate 18 is always inserted into the groove 30 of the insert plate 17. The multi-layered staggered insert plates 17 and the inner plate 18 form a complex labyrinthine channel, effectively trapping moisture and silt in the tortuous path, preventing them from entering the dynamic seal of the telescopic joint of the lifting hydraulic cylinder 21. The design of the slot 34 ensures that the telescopic joint does not interfere with the insert plate 17 during movement. This dustproof and moisture-proof component can adapt to the harsh environment of high humidity and abundant mud in tunnels, significantly reducing the risk of hydraulic oil emulsification and cylinder corrosion, and extending the service life of the lifting hydraulic cylinder 21.

[0026] It should be noted that both the inner plate 18 and the insert plate 17 are fixed to the inner wall of the telescopic bellows 13, and their fixing positions are located in the trough region between two adjacent crests of the telescopic bellows 13. Since the radial deformation of the trough is minimal during axial expansion and contraction, and the main deformation occurs at the crest, the fixing positions of the inner plate 18 and the insert plate 17 always remain relatively stable and will not exhibit significant swaying or misalignment with the radial expansion or contraction of the crest. In summary, the pleated structure of the telescopic bellows 13 will not cause any obstruction or risk of disengagement to the insertion and mating of the inner plate 18 and the insert plate 17, thus ensuring the integrity of the multi-layer labyrinth seal in any expansion or contraction position.

[0027] The double-ended bolt fastener 36 consists of a bolt body and nuts with threads at both ends.

[0028] The multi-section connecting mechanism includes a U-shaped seat 25, inside which is a ball joint 24. The extension end of the adjusting hydraulic cylinder 4 is connected to the ball joint 24. A pressing seat 28 is fixedly connected to one side of the U-shaped seat 25. Both ends of the pressing seat 28 are provided with rotating sleeves 26. A shaft 19 is rotatably inserted between the two rotating sleeves 26. A connecting seat 27 is rotatably sleeved on the outside of the shaft 19. A reinforcing shaft seat 32 is fixedly installed on one side of the connecting seat 27. The reinforcing shaft seat 32 is connected to the inside of the tensioning shell 5 through a rotating component. The rotating component includes a rotating joint 23. One end of the rotating joint 23 is connected to the inside of the tensioning shell 5, and the other end of the rotating joint 23 is rotatably connected to the inside of the reinforcing shaft seat 32.

[0029] like Figure 1 , Figure 2 and Figure 7 As shown, the telescopic end of the adjusting hydraulic cylinder 4 is connected to the ball joint 24, which is located inside the U-shaped seat 25. The ball joint 24 allows the telescopic end to rotate omnidirectionally relative to the U-shaped seat 25 in multiple directions. The U-shaped seat 25, through the pressing seat 28 and the rotating sleeve 26, allows the U-shaped seat 25 to rotate around its own axis on the outer surface of the insert shaft 19. A connecting seat 27 is rotatably sleeved on the outer middle of the insert shaft 19, and the connecting seat 27 can rotate independently relative to the insert shaft 19 about its axis.

[0030] The ball joint 24 is a multi-degree-of-freedom universal joint component used to adjust the universal deflection between the telescopic end of the hydraulic cylinder 4 and the U-shaped seat 25. It includes a ball head, a ball socket, a retaining ring, and a lubrication bushing. The ball head connects to the telescopic end of the hydraulic cylinder 4. The ball socket has a spherical groove that matches the ball head, enclosing it. The retaining ring is located at the end of the ball socket to prevent the ball head from dislodging under force, ensuring reliable hinge connection. The lubrication bushing is fitted between the ball head and the ball socket to reduce friction and ensure flexible rotation.

[0031] The tension shell 5 is rotatably engaged with the reinforcing shaft seat 32 outside the connecting seat 27 through the internally embedded rotating joint 23. It is connected to the prefabricated hanging parts on the side wall of the foundation pit or the crown beam set inside the foundation pit to achieve multi-angle suspension.

[0032] When the hook 6 needs to be suspended from the top of the tunnel or other external support structures, the support points at the top of the tunnel may be located at different heights, angles, or even have inclined surfaces. A single degree of freedom connection cannot ensure that the hook 6 fits smoothly. This invention provides multiple rotational degrees of freedom in series, so that the adjusting hydraulic cylinder 4 and the tensioning structure can meet the usage requirements.

[0033] Rotation 1: The ball joint 24 allows the tension shell 5 and the hook 6 to deflect in multiple directions relative to the axis of the adjusting hydraulic cylinder 4.

[0034] Rotational degree 2: The insert shaft 19 rotates within the rotating sleeve 26, providing rotational freedom about the insert shaft 19 as the axis.

[0035] Rotational degree three: The rotating connection between the connecting seat 27 and the insert shaft 19 provides another degree of rotational freedom around the same horizontal axis but relatively independent, which facilitates centering adjustment during installation.

[0036] Rotation degree four: Rotary joint 23 allows tension shell 5 to rotate about the axis of rotating joint 23 relative to reinforcing shaft seat 32.

[0037] The above structure enables the hook to tilt, swing, and rotate.

[0038] Pressure sensors 20 are installed on the outside of the lifting hydraulic cylinder 21. A hydrophobic layer is processed on the outer surface of the telescopic corrugated pipe 13. Slide beams 11 are installed at both ends of the bottom of the main bridge frame 1 and on the side close to the main beam 7. A sleeve 8 is slidably sleeved under the slide beam 11.

[0039] like Figure 7 As shown, the pressure sensor 20 monitors the load pressure of each lifting hydraulic cylinder 21 in real time. When the pressure on one side rises abnormally, the extension of the regulating hydraulic cylinder 4 on the same side and the screw depth of the screw 33 are adjusted according to the pressure signal to keep the bridge deck balanced. At this time, the staff can check it and adjust the corresponding structure.

[0040] A hydrophobic layer is processed on the outside of the telescopic corrugated pipe 13 to prevent water droplets from adhering.

[0041] Working Principle: The telescopic construction trestle's main beam lifting mechanism is installed at the tunnel or foundation pit construction site. The main bridge frame 1 serves as a fixed central section, with telescopic bridge frames 2 connected to both sides via telescopic mechanisms, allowing for trestle length adjustment. The lifting hydraulic cylinder 21 at the bottom of the main beam 7 bears the vertical load of the bridge deck and performs height adjustments. When the bridge deck elevation needs adjustment, the control device supplies oil to the lifting hydraulic cylinder 21, causing the piston rod to extend and retract, pushing the main beam 7 and main bridge frame 1 to rise and fall as a whole.

[0042] The telescopic hydraulic cylinder 15 drives the load-bearing beam 10 at the bottom of the telescopic cable tray 2 to move. When the telescopic hydraulic cylinder 15 extends, it pushes the telescopic cable tray 2 away from the main cable tray 1, while the compensation plate 16 slides outward from inside the reinforcing compensation shell 3. The bottom side of the compensation plate 16 is fixedly connected to the upper surface of the telescopic cable tray 2, thus always covering the telescopic cable tray 2 to form continuous bridge deck support. The reverse is true when it retracts. The sleeve 8 under the sliding beam 11 slides with the telescopic movement, providing auxiliary guidance.

[0043] A first sealing shell 9 and a second sealing shell 12, along with telescopic bellows 13, are installed on the outside of the two lifting hydraulic cylinders 21 on the same side to protect the cylinder barrels and telescopic joints. Specifically, the first sealing shell 9 is sleeved on the outside of the two lifting hydraulic cylinders 21, with one edge abutting against the outer sealing frame 31 inside the second sealing shell 12, which reduces the ingress of moisture. It is then locked by double-headed bolt fasteners 36 symmetrically arranged on both sides. Then, the two sets of separate telescopic bellows 13 above the first sealing shell 9 and the second sealing shell 12 are abutted together, and the inner plate 18 is inserted into the corresponding groove 30 to form a multi-layered staggered sealing structure. This not only prevents dust but also water vapor. Finally, sealant is applied to the inner edge of the telescopic bellows 13 above the first sealing shell 9 and the second sealing shell 12 to achieve a sealed connection between them. When the lifting hydraulic cylinder 21 extends or retracts, the telescopic bellows 13 extends or retracts accordingly. The insert plate 17 and the inner plate 18 always remain in the plugged state, effectively blocking external water vapor, mud, and dust from entering the cylinder. The telescopic bellows 13 is connected to the bottom of the main beam 7. When the main beam 7 moves up or down, the telescopic bellows 13 extends accordingly.

[0044] To alleviate the long-term load on the lifting hydraulic cylinder 21, this invention provides a suspension reinforcement structure consisting of a support column 14, an adjusting hydraulic cylinder 4, a multi-section connecting mechanism, a tensioning shell 5, a screw 33, and a hook 6. The support column 14 is fixed to both ends of the main beam 7. A connecting shaft 29 is rotatably inserted into one end of the support column 14, and a rotating seat 22 is sleeved on the connecting shaft 29. The rotating seat 22 can rotate around the axis of the connecting shaft 29. The cylinder body of the adjusting hydraulic cylinder 4 is fixed outside the rotating seat 22, thus allowing the adjusting hydraulic cylinder 4 to swing within a certain angle with the rotating seat 22. The multi-section connecting mechanism works by providing multiple independent degrees of rotational freedom, enabling the hook 6 to adapt to suspension points at multiple spatial angles: First, the ball joint 24 allows the extension end of the adjusting hydraulic cylinder 4 to deflect in all directions relative to the rear component; second, the engagement of the insert shaft 19 and the rotating sleeve 26 provides rotation about the horizontal axis; third, the rotating engagement of the connecting seat 27 and the insert shaft 19 provides another coaxial but relatively independent rotation; finally, the swivel joint 23 allows the tensioning shell 5 to rotate about another direction relative to the front component. This combination of degrees of freedom allows the hook 6 to adjust its pitch, swing, and rotation in space, ensuring stable contact and uniform force application regardless of the angle of the connection support points on the tunnel sidewall and the foundation pit cap beam.

[0045] Once the hook 6 is in place, rotating the screw 33 changes the extension length of the hook 6, thereby adjusting the preload. At this time, part of the vertical load is transmitted to the main beam 7 via the hook 6, tensioning shell 5, multi-section connecting mechanism, adjusting hydraulic cylinder 4, rotating seat 22, connecting shaft 29, and support column 14, forming a force flow path that transfers upward to the upper support system, thereby reducing the direct pressure on the lifting hydraulic cylinder 21. The pressure sensor 20 monitors the load of each lifting hydraulic cylinder 21 in real time. When the load exceeds the set range or the bridge deck needs to be rebalanced, the control device automatically adjusts the extension and retraction of the adjusting hydraulic cylinder 4 and the screw depth of the corresponding screw 33, dynamically distributing the suspension force and support force to maintain the bridge deck's stable level.

[0046] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A telescopic construction trestle main beam lifting mechanism, comprising a main bridge frame (1) and two telescopic bridge frames (2), characterized in that, The main bridge (1) is provided with main beams (7) at both ends of the bottom. The two main beams (7) are connected to the two telescopic bridges (2) respectively through the telescopic mechanism on the side away from each other. Two lifting hydraulic cylinders (21) are symmetrically arranged on both sides of the bottom of the two main beams (7). Dustproof and moisture-proof components are provided on the outside of the two lifting hydraulic cylinders (21) on the same side. Support columns (14) are provided at both ends of the outside of the two main beams (7). A connecting shaft (29) is rotatably inserted into one end of the support column (14). A rotating seat (22) is sleeved on the outside of the connecting shaft (29). An adjusting hydraulic cylinder (4) is fixedly arranged on the outside of the rotating seat (22). A tensioning shell (5) is connected to the telescopic end of the adjusting hydraulic cylinder (4) through a multi-section connecting mechanism. A screw (33) is threaded through both ends of the tensioning shell (5). A hook (6) is provided at the end of the two screws (33) away from each other.

2. The telescopic construction trestle main beam lifting mechanism according to claim 1, characterized in that, The telescopic mechanism includes two telescopic hydraulic cylinders (15), which are respectively set on one side of the main beam (7). A base (35) is fixedly set at the bottom of the telescopic bridge (2). A load-bearing beam (10) is set at the bottom of the telescopic bridge (2) and in the middle of the base (35). The telescopic ends of the two telescopic hydraulic cylinders (15) are connected to the outside of the load-bearing beam (10). A reinforcing compensation shell (3) is set above the main bridge (1). A compensation plate (16) is slidably connected inside the reinforcing compensation shell (3). The bottom of one side of the compensation plate (16) is fixedly connected to the upper surface of the telescopic bridge (2).

3. The telescopic construction trestle main beam lifting mechanism according to claim 1, characterized in that, The dustproof and moisture-proof component includes a first sealing shell (9) and a second sealing shell (12). The edge of the first sealing shell (9) extends outward to form an embedded sealing frame (31), and the edge of the second sealing shell (12) is embedded in the embedded sealing frame (31).

4. The telescopic construction trestle main beam lifting mechanism according to claim 3, characterized in that, Both the first sealing shell (9) and the second sealing shell (12) are provided with telescopic bellows (13). The inner wall of the telescopic bellows (13) inside the first sealing shell (9) is provided with multiple inner plates (18), and the inner wall of the second sealing shell (12) is provided with multiple insert plates (17). The multiple insert plates (17) and the multiple inner plates (18) are arranged at equal intervals from top to bottom along the inner wall of the telescopic bellows (13), and the two ends of the multiple insert plates (17) are provided with a hydraulic cylinder (21) for lifting. The expansion joint has a slot (34) for movement. Each of the multiple insert plates (17) has a groove (30) for insertion into multiple insert plates (18). The first sealing shell (9) and the second sealing shell (12) are connected on both sides by symmetrically installed double-headed bolt fasteners (36). The inner edge of the expansion bellows (13) located above the first sealing shell (9) and the second sealing shell (12) is connected by externally coated glue. The top of the expansion bellows (13) is sealed to the bottom of the main beam (7).

5. The telescopic construction trestle main beam lifting mechanism according to claim 1, characterized in that, The multi-section connecting mechanism includes a U-shaped seat (25), a ball joint (24) is provided inside the U-shaped seat (25), the extension end of the adjusting hydraulic cylinder (4) is connected to the ball joint (24), and a pressure seat (28) is fixedly connected to the outside side of the U-shaped seat (25).

6. The telescopic construction trestle main beam lifting mechanism according to claim 5, characterized in that, Both ends of the pressure seat (28) are provided with rotating sleeves (26), and a shaft (19) is rotatably inserted between the two rotating sleeves (26). A connecting seat (27) is rotatably sleeved on the outside of the shaft (19). A reinforcing shaft seat (32) is fixedly installed on one side of the connecting seat (27). The reinforcing shaft seat (32) is connected to the inside of the tensioning shell (5) through a rotating component provided inside.

7. The telescopic construction trestle main beam lifting mechanism according to claim 6, characterized in that, The rotating component includes a rotating joint (23), one end of which is connected to the inside of the tension shell (5), and the other end of which is rotatably connected to the inside of the reinforcing shaft seat (32).

8. The telescopic construction trestle main beam lifting mechanism according to claim 4, characterized in that, Pressure sensors (20) are provided on the outside of each lifting hydraulic cylinder (21). A hydrophobic layer is processed on the outer surface of the telescopic corrugated pipe (13). Slide beams (11) are provided at both ends of the bottom of the main bridge frame (1) and on the side close to the main beam (7). A sleeve (8) is slidably sleeved under the slide beam (11).

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