A stress buffer device for bridge expansion joint

Abstract

This invention provides a stress buffer device for bridge expansion joints, relating to the field of bridge engineering technology. It includes a pair of comb-tooth plates, which are interlocked and fixedly installed on box girders on both sides of the expansion joint. A pair of load-bearing blocks are fixed to vertical plates below the corresponding comb-tooth plates, with the blocks facing each other and each having an arched contact surface on its opposite side. An elastic plate with a spiral structure is arranged along the length of the load-bearing blocks and positioned between them, with its outer side in contact with the arched contact surface. A first adjusting member is mounted on the box girder to adjust a portion of the spiral gap of the elastic plate in the axial direction. A second adjusting member is mounted on the box girder to drive the elastic plate to rotate axially and fix it at the rotated angular position. This invention effectively adapts to differential deformation between bending box girders, significantly improving the overall stability and long-term durability of the expansion joint structure.

Description

Technical Field

[0001] This invention relates to the field of bridge engineering technology, and more specifically, to a stress buffering device for bridge expansion joints. Background Technology

[0002] Currently, in bridge engineering, expansion joints are typically installed between adjacent box girders to accommodate structural length changes caused by temperature variations, vehicle loads, and concrete shrinkage, thus mitigating the overall linear deformation of the bridge. However, in existing technologies, for adjacent box girders with a certain curvature, the stress state and deformation patterns in the width direction differ. When the bridge structure expands or contracts due to thermal expansion and contraction or load changes, the amount of expansion and contraction deformation in each box girder segment is often inconsistent, leading to uneven horizontal displacement at the expansion joint. Traditional expansion joint structures are mostly based on straight bridge designs and cannot adequately accommodate the differential deformation between curved box girders. This can easily lead to localized stress concentration during bridge operation, affecting the stability and durability of the structure.

[0003] Meanwhile, existing expansion joint structures mostly use rubber strips, rubber sheets, or rubber filler materials for gap filling and buffering. However, these materials are prone to aging, hardening, or detachment under long-term temperature cycling and horizontal compression, making it difficult to continuously absorb and release the horizontal deformation energy generated by the approach or departure of box girders. When deformation accumulates to a certain extent, the rubber material is prone to shear failure, causing the expansion joint to lose its stress buffering function, leading to gap failure or structural damage, and reducing the operational safety and service life of the bridge. Summary of the Invention

[0004] The purpose of this invention is to provide a stress buffer device for bridge expansion joints, which can effectively adapt to the differential deformation between curved box girders and significantly improve the overall stability and long-term durability of the expansion joint structure.

[0005] This invention is achieved through the following technical solution: A stress buffer device for use at bridge expansion joints, comprising: A pair of comb plates are provided, and the pair of comb plates are interlocked and fixedly installed on the box beams on both sides of the expansion joint. A pair of force-bearing blocks are provided, which are respectively fixed on the vertical plate below the corresponding comb plate. The pair of force-bearing blocks are arranged opposite each other, and each of the opposite sides is provided with an arched contact surface. An elastic plate, having a spiral structure, is arranged along the length of the force-bearing blocks and positioned between a pair of force-bearing blocks. The outer side of the elastic plate is in contact with the arched contact surface. The first adjusting component is disposed on the box girder and is used to adjust part of the pitch clearance of the elastic plate in the axial direction; The second adjusting component is disposed on the box girder and is used to drive the elastic plate to rotate in the axial direction and fix it at the angular position after rotation.

[0006] Furthermore, the inner side of the elastic plate is provided with an arc-shaped inner groove and an arc-shaped outer protrusion at the inner vertical position near the pair of force-bearing blocks. The arc-shaped inner groove and the arc-shaped outer protrusion are provided in pairs, and their respective arrangements are axially symmetrical about the axis of the elastic plate.

[0007] Furthermore, the second adjusting component includes a connecting frame, a rotating shaft, a slider, and a second adjusting motor. The connecting frame is arranged along the length direction of the elastic plate, and a pair of connecting frames are provided and symmetrically fitted onto the elastic plate. The outer wall of the elastic plate is provided with a protrusion, and the protrusion has a slot for engaging the connecting frame. The rotating shaft is arranged along the axis of the elastic plate and fixed to the connecting frame by a support rod. An outer frame is fixedly provided on both sides of the box girder in the width direction. The outer frame includes a positioning plate, and the plane of the positioning plate is perpendicular to the rotating shaft. The positioning plate has a sliding groove in the transverse direction, and the slider is slidably engaged in the sliding groove. The second adjusting motor is fixedly mounted on the slider, and the shaft of the second adjusting motor passes through the slider and is coaxially and fixedly connected to the rotating shaft. The second adjusting motor is a self-locking motor.

[0008] Furthermore, the outer frames on each side of the box girder in the width direction are arranged in pairs and fixedly installed on the box girder on both sides of the expansion joint. The positioning plates of the pair of outer frames overlap each other and are slidably arranged. The slider is simultaneously slidably engaged with the sliding groove of the pair of positioning plates.

[0009] Furthermore, the first adjusting member is disposed on both sides of the box girder. Each first adjusting member includes a rotating plate and a winch. The rotating plate is coaxially fixedly connected to the rotating shaft, and the winch is fixedly connected to the rotating plate. The movable end of the wire rope of the winch passes through the rotating plate and through a portion of the elastic plate and is fixed to one of the plates. The motor of the winch is a self-locking motor.

[0010] Furthermore, a pair of winches are provided on each side of the box girder in the width direction and are arranged symmetrically with the axis of the elastic plate as the center.

[0011] Furthermore, the wire ropes of the winches on both sides of the width direction of the box girder have overlapping portions.

[0012] Furthermore, the winch wire rope is not threaded through the middle of the elastic plate, and the winch wire rope is distributed on both sides of the elastic plate along the axial direction.

[0013] Furthermore, a pair of rubber blocks are symmetrically arranged on the rotating shaft. The rubber blocks are arranged in strip shape and along the length of the rotating shaft. The angle between the pair of rubber blocks and the pair of connecting frames is a right angle. The side of the rubber block away from the rotating shaft abuts against the inner side of the elastic plate.

[0014] Furthermore, an elastic folding plate is fixedly disposed below the pair of comb plates, the elastic folding plate being arranged along the length direction of the comb plates.

[0015] The technical solution of the present invention has at least the following advantages and beneficial effects: 1. This invention utilizes a spiral-shaped metal elastic plate positioned between a pair of comb-tooth plates, with its outer side conforming to the arched contact surface of the load-bearing block. This effectively buffers and absorbs the differential deformation along the horizontal direction caused by thermal expansion and contraction or load changes between adjacent box girders of a bridge. Compared to traditional rubber-filled structures, the main load-bearing component of this structure is a metal plate, which possesses higher shear resistance and anti-aging properties, making it less prone to fatigue, hardening, or detachment, significantly improving the service life and long-term stability of the expansion joint. Simultaneously, the linear contact between the arched contact surface and the spiral elastic plate ensures more uniform stress transmission, effectively preventing structural damage caused by localized stress concentration.

[0016] 2. This invention adjusts the pitch gap of the elastic plate in the axial direction using a first adjusting component, allowing the density between the spiral coils to be optimized according to the stress requirements of different areas. When the pitch is denser, the elastic plate needs to withstand greater pressure in that area to deform; when the pitch is sparser, deformation is more sensitive, thus achieving adaptive coordination of differential deformation at the horizontal expansion joints between curved box girders. The second adjusting component further optimizes the overall stiffness distribution by fine-tuning and locking the spiral angle, achieving differentiated deformation absorption and precise buffering. Therefore, this invention can achieve high durability and multi-segment differential energy absorption without relying on rubber materials, significantly improving the adaptability and service life of the expansion joint area. Attached Figure Description

[0017] Figure 1 A schematic diagram of the overall structure of a stress buffer device for bridge expansion joints provided by the present invention; Figure 2 for Figure 1 Enlarged view of section A; Figure 3 A top view of a stress buffer device for bridge expansion joints provided by the present invention; Figure 4 for Figure 3 Enlarged view of section B; Figure 5A cross-sectional view of a stress buffer device for bridge expansion joints provided by the present invention; Figure 6 This is a schematic diagram illustrating the structure of the elastic plate of this invention; Figure 7 This is a schematic diagram illustrating the structure of the first and second adjusting members of this invention; Figure 8 This is a schematic diagram illustrating the structure of the second adjusting member and the rubber block. Figure 9 This invention aims to show an exploded view of the wire rope of a winch distributed on both sides of an elastic plate along the axial direction. Figure 10 This invention aims to show an exploded view of the overlapping wire ropes of the winches on both sides of the box girder in the width direction; Reference numerals: 100-comb plate, 110-vertical plate, 200-stress block, 210-arched contact surface, 300-elastic plate, 310-arc-shaped inner groove, 320-arc-shaped outer convex ridge, 330-protrusion, 331-slot, 400-first adjusting component, 410-rotating plate, 420-winner, 421-wire rope, 4211-moving end, 500-second adjusting component, 510-connecting frame, 520-rotating shaft, 521-support rod, 522-rubber block, 530-slider, 540-second adjusting motor, 600-outer frame, 610-positioning plate, 611-sliding groove, 620-connecting frame, 700-bolt, 800-elastic folding plate, 900-box girder. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0020] The following is for reference Figures 1-10As shown in the figure, and further explained with reference to specific embodiments, this embodiment provides a stress buffer device for bridge expansion joints, including a comb plate 100. The comb plate 100 has a toothed structure and a pair of comb plates 100 are provided. The pair of comb plates 100 are interlocked with each other. Through this interlocking method, a stable meshing connection structure can be formed on both sides of the bridge expansion joint, which can ensure the lateral alignment accuracy and maintain a good sliding fit relationship when affected by thermal expansion and contraction.

[0021] A pair of comb plates 100 are fixedly installed on the box girder 900 on both sides of the expansion joint using high-strength bolts 700. Elastic washers can be used during installation to reduce vibration and prevent loosening. The comb plates 100 and vertical plates 110 are connected in a T-shape, with the vertical plates 110 fitting against the side wall of the box girder 900. The T-shaped arrangement allows the vertical plates 110 to provide stronger vertical support to the comb plates 100, thereby improving the overall bending and shear stability of the connection. In different embodiments, the comb plates 100 can be made of corrosion-resistant stainless steel or galvanized steel to enhance their durability and long-term rust resistance in complex climatic environments.

[0022] A pair of load-bearing blocks 200 are symmetrically installed. Each pair of load-bearing blocks 200 is welded or connected to the vertical plate 110 below the corresponding comb plate 100 by bolts 700. Reinforcing ribs can be provided at the connection between the load-bearing block 200 and the vertical plate 110 to prevent localized stress concentration. The pair of load-bearing blocks 200 are arranged opposite each other, and each opposite side has an arched contact surface 210. The arched contact surface 210 is arc-shaped, and this curved contact form makes the stress distribution more uniform, reducing localized wear or stress peaks caused by line contact. The arched contact surface 210 can be customized with different radii according to the span or bending radius of the box girder 900 to adapt to different bridge structural forms. The load-bearing blocks 200 can be made of high-strength alloy steel or heat-treated structural steel to ensure stable load-bearing capacity under long-term repeated expansion and contraction deformation.

[0023] The elastic plate 300 has a spiral structure, arranged along the length of the force-bearing blocks 200, and positioned between a pair of force-bearing blocks 200. The outer side of the elastic plate 300 is in contact with the arched mating surface 210. Through the structural fit between the arc surfaces, multi-point force transmission can be achieved, dispersing horizontal expansion and contraction deformation during contact. The elastic plate 300 is made of a highly elastic metal spring sheet, such as spring steel or shape memory alloy, to maintain stable recovery performance under long-term cyclic deformation. In some embodiments, a wear-resistant gasket can be placed between the elastic plate 300 and the force-bearing blocks 200 to reduce friction and extend the structural life. By replacing rubber fillers with this metal elastic plate 300, the overall shear resistance and durability can be significantly improved, effectively avoiding the problems of aging, hardening, or detachment of traditional rubber under alternating temperatures.

[0024] The first adjusting component 400 is mounted on the box girder 900 and is used to adjust a portion of the pitch clearance of the elastic plate 300 in the axial direction. This structure allows for changes in the pitch density at different positions of the elastic plate 300 to accommodate the differential deformation of the curved box girder 900 in the horizontal expansion and contraction direction. In different embodiments, the first adjusting component 400 can be driven by multiple small pneumatic or electric cylinders, enabling precise control of the pitch clearance variation range. Pneumatic cylinder drive is suitable for applications requiring flexible adjustment, while electric cylinder drive is suitable for bridge structures requiring high positioning accuracy. The control of the adjusting component can be linked with a bridge temperature monitoring system or strain monitoring system to achieve automated adjustment, maintaining optimal buffering performance of the device under different environments.

[0025] The second adjusting component 500 is mounted on the box girder 900 and is used to drive the elastic plate 300 to rotate axially and fix it at the rotated angular position. Rotation changes the contact points on the inner and outer sides of the elastic plate 300, thereby adjusting the elastic response characteristics. In different embodiments, the second adjusting component 500 can be directly driven by a motor. The motor can be a servo motor or stepper motor with a self-locking function to ensure that the adjusted angular position can be stably maintained. The motor drives the rotating shaft 520 to rotate through a reduction mechanism, thereby achieving high-precision angle control.

[0026] Furthermore, on the inner side of the elastic plate 300, near the inner vertical position of the pair of force-bearing blocks 200, there are arc-shaped inner grooves 310 and arc-shaped outer protrusions 320, respectively. The arc-shaped inner grooves 310 and arc-shaped outer protrusions 320 are arranged in pairs, and each is axially symmetrical about the axis of the elastic plate 300. To ensure fitting accuracy, the radius of curvature, width, and height of the grooves and protrusions should be designed and registered according to the elastic modulus of the elastic plate 300 material and the stress requirements. During manufacturing, they can be CNC machined or stamped, and wear-resistant treatment or wear-resistant strips can be applied to the contact surfaces to reduce contact wear. The paired and axially symmetrical arrangement of the grooves and protrusions facilitates manufacturing symmetry and also makes it easy to achieve force balance during assembly through concentricity adjustment.

[0027] Through this symmetrical arrangement, when the elastic plate 300 rotates in the forward or reverse direction along the axial direction, the local cross-sectional configuration of the elastic plate 300 and its relative position with the arched contact surface 210 of the force-bearing block 200 can be changed, thereby substantially altering the deformation position and working cross-section of the elastic plate 300. When the arc-shaped inner groove 310 is close to the center position of the elastic plate 300 in the vertical direction, the effective cross-section of the elastic plate 300 in that region decreases, and the local stiffness and elastic restoring force decrease, making it easier to produce bending and compressive deformation under the same load. Conversely, when the arc-shaped outer convex ridge 320 is close to the vertical center position, the effective cross-section at that location increases, and the local stiffness and elastic force increase, requiring greater pressure to produce the same degree of deformation. Therefore, through rotational adjustment, a zoned stiffness distribution can be achieved in the axial direction. The dense pitch region combined with the convex ridge provides higher stiffness, while the sparse pitch region combined with the groove provides lower stiffness, forming a gradient response to differential deformation along the horizontal direction.

[0028] The dynamic working mechanism of this structure is also reflected in the alternating force and the migration of the contact surface: during bridge operation, as the displacement on both sides of the expansion joint changes, the elastic plate 300 continuously switches the main deformation position through the force-bearing block 200 and the concave-convex cooperation, realizing the rotational distribution of load between the spiral rings and avoiding local fatigue damage caused by long-term bearing on a single ring. Combined with the precise positioning of the rotation angle by the second adjusting component 500, the stiffness distribution of the elastic plate 300 can be optimized during construction and installation or regular maintenance.

[0029] Reference Figure 5 and Figure 6 As shown, specifically, the second adjusting component 500 includes a connecting frame 510, a rotating shaft 520, a slider 530, and a second adjusting motor 540. The connecting frame 510 is arranged along the length of the elastic plate 300, and a pair of frames are symmetrically fitted onto the elastic plate 300 to form a stable rotational linkage structure. The outer wall of the elastic plate 300 has a protrusion 330, and the protrusion 330 has a slot 331 for engaging the connecting frame 510, ensuring synchronization during rotation. The rotating shaft 520 is arranged along the axis of the elastic plate 300 and is fixedly connected to the connecting frame 510 via a support rod 521. The support rod 521 adopts a detachable connection structure or a welded structure for easy maintenance and replacement. When the second adjusting motor 540 drives the rotating shaft 520 to rotate, the connecting frame 510 can drive the elastic plate 300 to rotate synchronously, ensuring the coordination and accuracy of the rotational transmission.

[0030] The outer frames 600 on each side of the box girder 900 in the width direction are arranged in pairs and fixed to the box girder 900 on both sides of the expansion joint. The positioning plates 610 of one pair of outer frames 600 overlap and slide together, and the plane of the positioning plates 610 is perpendicular to the rotation axis 520. The positioning plates 610 have sliding grooves 611 in the transverse direction. The slider 530 slides and engages in the sliding grooves 611 of the pair of positioning plates 610, so that the slider 530 can slide freely in the sliding grooves 611 during the deformation of the box girder 900 expansion joint. This ensures that the axis of the elastic plate 300 always coincides with the axis of the arched contact surface 210 of the force block 200 when deformed under force, preventing jamming. The second adjusting motor 540 is fixedly mounted on the slider 530. Its shaft passes through the slider 530 and is coaxially fixedly connected to the rotation axis 520. A self-locking motor is used to achieve rotational locking. The motor integrates a worm gear structure, which can maintain the angular position stability after power failure, thereby ensuring system safety.

[0031] The external scaffold 600 also includes a connecting frame 620. The positioning plate 610 is connected to the connecting frame 620 by bolts 700. The connecting frame 620 is a rectangular frame structure and is fixed to the box girder 900 by high-strength bolts 700. This connection method facilitates installation and disassembly and can be modularly arranged according to the actual width of the bridge's expansion joints, ensuring that the overall structure has sufficient anti-slip capacity and stability under bridge temperature changes and loads.

[0032] Reference Figure 7 and Figure 8 As shown, the first adjusting member 400 is disposed on both sides of the box girder 900. Each first adjusting member 400 includes a rotating plate 410 and a winch 420. The rotating plate 410 is coaxially fixedly connected to the rotating shaft 520. When the rotating shaft 520 rotates, it drives the rotating plate 410 and the winch 420 to rotate synchronously, thereby keeping the tension direction of the wire rope 421 consistent with the output axis and preventing uneven force caused by winding deviation. The winch 420 is fixedly connected to the rotating plate 410. The movable end 4211 of its wire rope 421 passes through the rotating plate 410 and through a part of the elastic plate 300 before being fixed to one of the plates. The motor of the winch 420 adopts a self-locking motor structure, which can automatically lock the output shaft after stopping operation, ensuring the stable and reliable state after adjustment.

[0033] In some embodiments, the winches 420 on each side of the box girder 900 in the width direction can be configured as a pair and arranged symmetrically with the axis of the elastic plate 300 as the center to ensure uniform tension distribution and prevent pitch adjustment deviation caused by unilateral force.

[0034] As an optional embodiment, the wire ropes 421 of the winches 420 on both sides of the box girder 900 have a partially overlapping area. By controlling the tension and relaxation of the wire ropes 421 on both sides respectively, the pitch of the middle of the elastic plate 300 can be adjusted within a wider range, achieving fine adjustment in multiple areas.

[0035] In another alternative embodiment, the steel wire rope 421 is not threaded through the middle of the elastic plate 300, and the steel wire rope 421 of the winch 420 is distributed on both sides of the elastic plate 300, so that the pitch at both ends can be adjusted independently, making the force state of the spiral elastic plate 300 more balanced.

[0036] Furthermore, a pair of rubber blocks 522 are symmetrically arranged on the rotating shaft 520. The rubber blocks 522 are strip-shaped and arranged along the length of the rotating shaft 520. The angle between the pair of rubber blocks 522 and the connecting frame 510 is a right angle. The side of the rubber block 522 away from the rotating shaft 520 abuts against the inner side of the elastic plate 300. The elasticity of the rubber block 522 can limit the offset range of the elastic plate 300, so that its deformation is concentrated in the area close to the vertical center line. At the same time, the rubber block 522 has resilience and cushioning properties, and will not cause jamming, thereby improving the overall fatigue resistance and service life.

[0037] In addition, an elastic folding plate 800 is fixedly installed below a pair of comb plates 100 and above a pair of load-bearing blocks 200. The elastic folding plate 800 is a metal spring plate and is arranged along the length of the comb plates 100. The elastic folding plate 800 is fixed to the bottom of the comb plates 100 by bolts 700 or welding. It can not only protect the expansion joint and block water, but also provide additional buffering and energy absorption capacity when the bridge deforms. Its material can be stainless steel spring sheet or composite metal spring sheet, which is both corrosion resistant and flexible, thereby further improving the overall protection and stability of the device.

[0038] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A stress buffer device for use at bridge expansion joints, characterized in that, include: A pair of comb plates (100) are provided, and the pair of comb plates (100) are interlocked and fixedly installed on the box beams (900) on both sides of the expansion joint; A pair of force-bearing blocks (200) are provided, which are respectively fixed on the vertical plate (110) below the corresponding comb plate (100). The pair of force-bearing blocks (200) are arranged opposite to each other, and each of them has an arched contact surface (210) on the opposite side. The elastic plate (300) has a spiral structure and is arranged along the length of the force-bearing block (200) and is disposed between a pair of force-bearing blocks (200). The outer side of the elastic plate (300) is in contact with the arched contact surface (210). The first adjusting member (400) is disposed on the box girder (900) and is used to adjust part of the pitch clearance of the elastic plate (300) in the axial direction; The second adjusting member (500) is disposed on the box girder (900) and is used to drive the elastic plate (300) to rotate in the axial direction and fix it at the angular position after rotation.

2. The stress buffer device for bridge expansion joints according to claim 1, characterized in that, The inner side of the elastic plate (300) is provided with an arc-shaped inner groove (310) and an arc-shaped outer protrusion (320) respectively at the inner vertical position near the pair of force-bearing blocks (200). The arc-shaped inner groove (310) and the arc-shaped outer protrusion (320) are provided in pairs, and each is arranged symmetrically about the axis of the elastic plate (300).

3. The stress buffer device for bridge expansion joints according to claim 1, characterized in that, The second adjusting component (500) includes a connecting frame (510), a rotating shaft (520), a slider (530), and a second adjusting motor (540). The connecting frame (510) is arranged along the length of the elastic plate (300). A pair of connecting frames (510) are provided and symmetrically fitted onto the elastic plate (300). The outer wall of the elastic plate (300) is provided with a protrusion (330), and the protrusion (330) has a slot (331) for engaging the connecting frame (510). The rotating shaft (520) is arranged along the axis of the elastic plate (300) and fixed to the connecting frame (510) by a support rod (521). An outer frame (600) is fixedly installed on both sides of the box girder (900) in the width direction. The outer frame (600) includes a positioning plate (610). The plane of the positioning plate (610) is perpendicular to the rotating shaft (520). The positioning plate (610) has a sliding groove (611) in the transverse direction. The slider (530) is slidably engaged in the sliding groove (611). The second adjusting motor (540) is fixedly installed on the slider (530). The shaft of the second adjusting motor (540) passes through the slider (530) and is coaxially fixedly connected to the rotating shaft (520). The second adjusting motor (540) is a self-locking motor.

4. The stress buffer device for bridge expansion joints according to claim 3, characterized in that, The outer frame (600) on each side of the box girder (900) in the width direction is arranged in pairs and fixedly installed on the box girder (900) on both sides of the expansion joint. The positioning plates (610) of the pair of outer frames (600) overlap each other and are slidably arranged. The slider (530) is simultaneously slidably engaged in the sliding groove (611) of the pair of positioning plates (610).

5. The stress buffer device for bridge expansion joints according to claim 3, characterized in that, The first adjusting member (400) is disposed on both sides of the box girder (900). Each first adjusting member (400) includes a rotating plate (410) and a winch (420). The rotating plate (410) is coaxially fixedly connected to the rotating shaft (520). The winch (420) is fixedly connected to the rotating plate (410). The movable end (4211) of the wire rope (421) of the winch (420) passes through the rotating plate (410) and through a portion of the elastic plate (300) and is fixed to one of the plates. The motor of the winch (420) is a self-locking motor.

6. The stress buffer device for bridge expansion joints according to claim 5, characterized in that, A pair of winches (420) are provided on each side of the box girder (900) in the width direction and are arranged symmetrically with the axis of the elastic plate (300) as the center.

7. The stress buffer device for bridge expansion joints according to claim 5, characterized in that, The wire ropes (421) of the winches (420) on both sides of the width direction of the box girder (900) have overlapping portions.

8. The stress buffer device for bridge expansion joints according to claim 5, characterized in that, The elastic plate (300) is not equipped with a wire rope (421) of a winch (420) in the middle position, and the wire rope (421) of the winch (420) is distributed on both sides of the elastic plate (300) in the axial direction.

9. The stress buffer device for bridge expansion joints according to claim 3, characterized in that, A pair of rubber blocks (522) are symmetrically arranged on the rotating shaft (520). The rubber blocks (522) are arranged in strip shape and along the length direction of the rotating shaft (520). The angle between the pair of rubber blocks (522) and the pair of connecting frames (510) is a right angle. The side of the rubber block (522) away from the rotating shaft (520) abuts against the inner side of the elastic plate (300).

10. The stress buffer device for bridge expansion joints according to any one of claims 1-9, characterized in that, An elastic folding plate (800) is fixedly disposed below a pair of comb plates (100), the elastic folding plate (800) being arranged along the length direction of the comb plates (100).

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