Bottom-holding protection balancing device of bridge fabrication machine

Abstract

The invention provides a bottom-holding protection balancing device of a bridge fabrication machine, which belongs to the technical field of continuous beam construction and is mounted on a truss of the bridge fabrication machine, and the bridge fabrication machine is positioned on a non-overline construction side and comprises a truss connecting part, a clamping part and a counterweight connecting part. Wherein the truss connecting part is arranged on the truss in a sleeving manner. The clamping part is vertically arranged on the truss connecting part in a sliding mode and located below the truss, and a space used for containing the truss is defined by the truss connecting part and the clamping part. And the counterweight connecting part is connected with the clamping part through a counter-force assembly and is used for hanging a counterweight. When the counter-weight object generates downward acting force on the counter-weight connecting part, the counter-force assembly generates upward acting force on the clamping part, so that the clamping part ascends and abuts against the truss. According to the bottom-holding protection balancing device of the bridge fabrication machine, the balance force generated by the counter weight is utilized, the requirement for balanced and symmetrical construction of cantilever sections can be met, and meanwhile a complete bottom-holding protection device does not need to be additionally installed.

Description

Technical Field

[0001] The invention belongs to the technical field of continuous beam construction, and more specifically, relates to a bottom protection balancing device for a bridge-building machine. Background Art

[0002] The suspended pouring method is a construction process used in bridge construction. Its main principle is to use a movable bridge-building machine as a working platform to symmetrically pour concrete beam sections on both sides of the pier. First, pour the starting section on the top of the pier, then install the bridge-building machine in place, and move the bridge-building machine to advance the construction section by section. Construction workers perform a series of operations such as steel bar binding, formwork installation, and concrete pouring in the bridge-building machine. The suspended pouring method is an open high-altitude operation and there is a risk of falling objects from high altitudes. When construction is carried out across the ground road, it will seriously endanger the safety of vehicles and pedestrians on the ground. Therefore, when suspended pouring is carried out above the ground road, a bottom protection device is often installed on the truss of the bridge-building machine to ensure the safety of vehicles and pedestrians on the ground.

[0003] During the construction of existing bridges, bridge-building machines are used in pairs for cantilever symmetrical casting. When the bridge-building machine on one side needs to install a bottom protection device when crossing the ground road, the bridge-building machine on the other side needs to install the same bottom protection device even if it does not cross the line for construction, to meet the needs of balanced and symmetrical construction of the cantilever segments. This requires an additional bottom protection device to be occupied during implementation, resulting in idleness and waste of the bottom protection device on the side that does not cross the line for construction. Summary of the invention

[0004] The object of the present invention is to provide a bottom protection balancing device for a bridge-building machine, aiming to meet the needs of balanced and symmetrical construction of cantilever segments.

[0005] To achieve the above object, the technical solution adopted by the present invention is: to provide a bottom protection balance device for a bridge-building machine, which is installed on the truss of the bridge-building machine, and the bridge-building machine is located on the non-crossing construction side, comprising: A truss connecting portion, sleeved on the truss; A clamping portion is vertically slidably disposed on the truss connecting portion and is located below the truss, wherein the truss connecting portion and the clamping portion enclose a space for accommodating the truss; A counterweight connecting portion, connected to the clamping portion via a reaction force assembly, and used for hanging a counterweight object; Wherein, when the counterweight object generates a downward force on the counterweight connecting portion, the reaction force assembly generates an upward force on the clamping portion, so that the clamping portion rises and presses against the truss.

[0006] In a possible implementation, the reaction force component includes: A sliding rod, horizontally fixedly disposed on the truss connecting portion and located below the clamping portion; Two sliding blocks are respectively slidably sleeved on the sliding rod; Two connecting rods, one end of which is hinged to the clamping portion and the other end of which is hinged to the slider, and which correspond to the slider one by one; Two connecting ropes, one end of which is fixed to the slider and the other end of which is fixed to the counterweight connecting part, correspond to the sliders one by one.

[0007] In a possible implementation, a limiting portion is fixedly provided on each of the two sliding blocks, and the limiting portion is horizontally slidably connected to the truss connecting portion; When the clamping portion abuts against the truss, the two limiting portions approach each other and abut against two sides of the truss respectively; When the clamping portion is separated from the truss, the two limiting portions move away from each other and separate from the truss.

[0008] In a possible implementation, side rollers are provided on both sides of the truss connection portion for vertical rotation; When the clamping portion is disengaged from the truss, the side rollers can abut against the truss so that the truss connecting portion is adapted to move along the length direction of the truss; When the clamping portion abuts against the truss, the limiting portion abuts against the truss, so that a gap exists between the side roller and the truss.

[0009] In a possible implementation, an upper roller is horizontally rotatably arranged above the truss, the upper roller is vertically slidably connected to the truss connecting part through an upper roller connecting part, and the upper roller connecting part abuts against the limiting part; When the two limiting parts are away from each other, the upper roller extends from the inner top wall of the truss connecting part and abuts against the upper surface of the truss; When the two limiting portions are close to each other, the upper roller is retracted into the truss connecting portion, so that the inner top wall of the truss connecting portion overlaps the upper surface of the truss.

[0010] In a possible implementation, the limiting portion has a push-up inclined surface, an extension portion is fixedly provided on the upper roller connecting portion, and a matching portion suitable for abutting against the push-up inclined surface is fixedly provided on the extension portion; When the two limiting parts move away from each other, the matching part slides along the pushing inclined surface and descends; When the two limiting portions are close to each other, the matching portion slides and rises along the pushing inclined surface.

[0011] In a possible implementation, the push inclined surface is located on a side of the limiting portion away from the truss, the limiting portion is provided with a notch for the extension portion to pass through laterally and slide up and down, and the matching portion abuts against the outer side of the limiting portion.

[0012] In a possible implementation, the reaction force assembly further includes an elastic member for pushing the two sliders away from each other, and the elastic member is disposed between the two sliders and sleeved on the slide rod.

[0013] In a possible implementation, two fixed pulleys are rotatably provided on the bottom surface of the truss connecting portion, and the connecting ropes correspond to the fixed pulleys one by one and are wound around the circumferential surfaces of the fixed pulleys.

[0014] In a possible implementation, a safety hook is fixedly provided at the bottom end of the counterweight connecting portion.

[0015] Compared with the prior art, the bottom protection balancing device of a bridge-building machine provided by the present invention has the following beneficial effects: first, the truss connection part is mounted on the truss to preliminarily connect the truss connection part with the truss. Then, a counterweight is hung on the counterweight connection part so that the counterweight exerts a downward force on the counterweight connection part. At this time, the reaction force assembly converts this downward force into an upward force on the clamping part, so that the clamping part rises and presses against the truss, so that the non-cross-line construction side can meet the requirements of balanced and symmetrical construction of the cantilever segment by only installing the bottom protection balancing device and utilizing the balancing force generated by the counterweight, without the need to install a complete bottom protection device, thereby effectively avoiding the idleness and waste of the bottom protection device on the non-cross-line construction side, saving equipment costs, and improving the rational utilization of resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A schematic diagram of a structure in which a bottom protection and balancing device for a bridge-building machine provided by an embodiment of the present invention is installed on a truss; Figure 2 A schematic diagram of the overall structure of a bottom protection and balancing device for a bridge-building machine provided in an embodiment of the present invention; Figure 3 A front view of a bottom protection and balancing device for a bridge-building machine provided by an embodiment of the present invention; Figure 4A cross-sectional view of a bottom protection and balancing device for a bridge-building machine provided by an embodiment of the present invention; Figure 5 A cross-sectional view from another angle of the bottom protection and balancing device of the bridge-building machine provided in an embodiment of the present invention.

[0018] In the figure: 1. truss connection part; 2. clamping part; 3. counterweight connection part; 31. safety hook; 41. sliding rod; 42. sliding block; 43. connecting rod; 44. connecting rope; 45. elastic member; 5. limiting part; 51. pushing inclined surface; 52. notch; 6. side roller; 71. upper roller; 72. upper roller connection part; 73. extension part; 74. matching part; 8. fixed pulley; 9. truss. DETAILED DESCRIPTION

[0019] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0020] See also Figure 1 , Figure 2 and Figure 3 , a bottom protection and balancing device for a bridge-building machine provided by the present invention is now described. A bottom protection and balancing device for a bridge-building machine is installed on the truss 9 of the bridge-building machine. The bridge-building machine is located on the side of the non-cross-line construction, and includes a truss connection part 1, a clamping part 2 and a counterweight connection part 3. Among them, the truss connection part 1 is sleeved on the truss 9. The clamping part 2 is vertically slidably arranged on the truss connection part 1 and is located below the truss 9. The truss connection part 1 and the clamping part 2 form a space for accommodating the truss 9. The counterweight connection part 3 is connected to the clamping part 2 through a reaction force component, which is used to hang a counterweight. When the counterweight generates a downward force on the counterweight connection part 3, the reaction force component generates an upward force on the clamping part 2, so that the clamping part 2 rises and presses against the truss 9.

[0021] Specifically, the truss connection part 1 is sleeved on the truss 9, providing a stable connection foundation for the entire bottom protection balance device, ensuring that the device can be firmly attached to the truss 9 of the bridge-building machine and will not easily loosen or fall off. At the same time, the sleeve connection method also facilitates construction personnel to adjust the position of the truss connection part 1 on the truss 9. According to actual needs, construction personnel can hang a counterweight of corresponding weight on the counterweight connection part 3, and the counterweight will exert a downward force on the counterweight connection part 3 due to its own gravity. Through the action of the reaction force component, this downward force is converted into an upward force on the clamping part 2, so that the clamping part 2 can rise in the vertical direction and finally press against the truss 9, thereby achieving a stable connection of the truss connection part 1 on the truss 9.

[0022] By installing the truss connection part 1 on the non-crossing construction side and utilizing the balancing force generated by the counterweight, it is possible to meet the mechanical requirements of balanced and symmetrical construction of the cantilever segment without installing a complete bottom protection device. This not only effectively avoids the idleness and waste of the bottom protection device on the non-crossing construction side, but also improves the rational utilization rate of resources in the entire construction process, making the configuration of construction resources more reasonable.

[0023] Exemplarily, the reaction force assembly includes a gear horizontally rotatably arranged on the truss connection part 1, a first rack fixedly arranged on the lower surface of the clamping part 2, and a second rack fixedly arranged on the upper surface of the counterweight connection part 3. The first rack and the second rack are respectively located on both sides of the gear and mesh with the gear. The first rack and the second rack are both vertically slidably connected to the truss connection part 1. When the second rack moves downward with the counterweight connection part 3, the gear rotates, thereby driving the first rack to move upward, so that the clamping part 2 rises. When the counterweight is not hung, the clamping part 2 naturally descends under the action of gravity, so that the counterweight connection part 3 rises.

[0024] In some embodiments, see Figure 2 , Figure 3 and Figure 4 The reaction force assembly includes a slide bar 41, two sliders 42, two connecting rods 43 and two connecting ropes 44. The slide bar 41 is horizontally fixed on the truss connection part 1 and is located below the clamping part 2. The two sliders 42 are slidably sleeved on the slide bar 41. One end of the two connecting rods 43 is hinged to the clamping part 2 and the other end is hinged to the slider 42. The connecting rods 43 correspond to the sliders 42 one by one. One end of the two connecting ropes 44 is fixed to the slider 42 and the other end is fixed to the counterweight connection part 3. The connecting ropes 44 correspond to the sliders 42 one by one.

[0025] Specifically, when the counterweight is hung on the counterweight connection part 3 and generates a downward force, the connecting rope 44 is subjected to tension and pulls the corresponding slider 42 to slide on the slide rod 41. The slider 42 transmits the force to the clamping part 2 through the connecting rod 43, so that the clamping part 2 can move upward, realizing the conversion of the weight of the counterweight into an effective clamping force on the truss 9, ensuring that the truss connection part 1 can be firmly connected to the truss 9.

[0026] Based on the above embodiments, further see Figure 2 , Figure 3 and Figure 4 The two sliders 42 are both fixed with a limit portion 5, and the limit portion 5 is horizontally slidably connected to the truss connecting portion 1. When the clamping portion 2 is against the truss 9, the two limit portions 5 are close to each other and respectively against the two sides of the truss 9. When the clamping portion 2 is separated from the truss 9, the two limit portions 5 are separated from each other and separated from the truss 9.

[0027] Specifically, when the clamping portion 2 is against the truss 9, the two limiting portions 5 will approach each other and respectively against the two sides of the truss 9. At this time, not only does the clamping portion 2 itself tightly against the truss 9, exerting a clamping force on the truss 9 from the top and bottom directions, but the limiting portions 5 also horizontally limit the truss 9 from both sides. The inner top wall of the truss connecting portion 1, the clamping portion 2 and the two limiting portions 5 are jointly attached to the outer peripheral surface of the truss 9, thereby forming a tight connection relationship with the truss 9, which can effectively prevent shaking or loosening when subjected to external forces, thereby improving safety during the construction process.

[0028] When the position of the truss connection part 1 needs to be moved, the counterweight is removed from the counterweight connection part 3, and the clamping part 2 will naturally fall under the action of gravity without the support of the connecting rod 43, thereby separating from the truss 9. At the same time, the two sliders 42 will move away from each other under the pushing action of the connecting rod 43, so that the two limit parts 5 will also move away from each other and separate from the truss 9, thereby facilitating the construction personnel to move the truss connection part 1.

[0029] In some embodiments, see Figure 2 , Figure 3 and Figure 4 , both sides of the truss connection part 1 are provided with side rollers 6 for vertical rotation. When the clamping part 2 is separated from the truss 9, the side rollers 6 can abut against the truss 9, so that the truss connection part 1 is suitable for moving along the length direction of the truss 9. When the clamping part 2 abuts against the truss 9, the limiting part 5 abuts against the truss 9, so that there is a gap between the side rollers 6 and the truss 9.

[0030] When the clamping part 2 is separated from the truss 9, the two limiting parts 5 also move away from each other and separate from the truss 9. At this time, when the truss connecting part 1 is moved along the truss 9, the side rollers 6 can contact and roll with the truss 9, reducing the friction force, making the truss connecting part 1 move more smoothly. When the clamping part 2 is against the truss 9, the limiting part 5 is also against the truss 9, so that there is a gap between the side rollers 6 and the truss 9. In this state, the side rollers 6 are prevented from interfering with the stability of the device.

[0031] Based on the above embodiments, further see Figure 2 , Figure 4 and Figure 5 , an upper roller 71 is horizontally rotatably arranged above the truss 9, and the upper roller 71 is vertically slidably connected to the truss connection part 1 through an upper roller connection part 72, and the upper roller connection part 72 abuts against the stopper 5. When the two stoppers 5 move away from each other, the upper roller 71 extends from the inner top wall of the truss connection part 1 and abuts against the upper surface of the truss 9. When the two stoppers 5 move closer to each other, the upper roller 71 is retracted into the truss connection part 1, so that the inner top wall of the truss connection part 1 overlaps the upper surface of the truss 9.

[0032] Specifically, when the truss connection part 1 needs to be moved, the clamping part 2 and the limiting part 5 are both separated from the truss 9. At this time, the upper roller connection part 72 extends from the inner top wall of the truss connection part 1, so that the upper roller 71 is against the upper surface of the truss 9, and the side roller 6 can be against the side wall of the truss 9, so that the truss connection part 1 moves more smoothly on the truss 9, greatly reducing the friction resistance.

[0033] When the two limiting parts 5 are close to each other, the upper roller 71 is retracted into the truss connecting part 1, so that the inner top wall of the truss connecting part 1 overlaps the upper surface of the truss 9. At this time, the device mainly relies on the close fit between the clamping part 2 and the truss 9 and the limiting effect of the limiting part 5 to achieve stability on the truss 9. After the upper roller 71 is retracted into the truss connecting part 1, it will not interfere with this stable connection, further enhancing the overall stability of the device.

[0034] In some embodiments, see Figure 2 , Figure 3 and Figure 4 The limiting part 5 has a push-up inclined surface 51, an extension part 73 is fixedly provided on the upper roller connecting part 72, and a matching part 74 suitable for contacting with the push-up inclined surface 51 is fixedly provided on the extension part 73. When the two limiting parts 5 move away from each other, the matching part 74 slides and descends along the push-up inclined surface 51. When the two limiting parts 5 move toward each other, the matching part 74 slides and ascends along the push-up inclined surface 51.

[0035] Specifically, when the two limiting parts 5 move away from each other, the matching part 74 will descend along the pushing inclined surface 51 under the pushing action of the pushing inclined surface 51, the matching part 74 drives the extending part 73, and the extending part 73 drives the upper roller connecting part 72, so that the upper roller 71 extends from the inner top wall of the truss connecting part 1.

[0036] When the two limiting parts 5 are close to each other, the matching part 74 loses the pushing effect of the pushing inclined surface 51, so that the truss connecting part 1 naturally drops and overlaps the truss 9. At this time, the upper roller connecting part 72 can be retracted into the truss connecting part 1, thereby realizing the retraction of the upper roller 71.

[0037] Based on the above embodiments, further see Figure 2 , Figure 4 and Figure 5 The pushing inclined surface 51 is located on the side of the limiting portion 5 away from the truss 9 , and a notch 52 is provided on the limiting portion 5 for the extending portion 73 to pass through horizontally and slide up and down, and the matching portion 74 is against the outer side of the limiting portion 5 .

[0038] The setting of the notch 52 provides a clear path and space limitation for the upward and downward sliding of the extension portion 73, so that the extension portion 73 and the matching portion 74 thereon can remain within a predetermined trajectory during the movement, further enhancing the stability of the entire matching structure.

[0039] In some embodiments, see Figure 3 The reaction force assembly also includes an elastic member 45 for pushing the two sliders 42 away from each other. The elastic member 45 is arranged between the two sliders 42 and sleeved on the slide rod 41.

[0040] Exemplarily, the elastic member 45 is a spring, and both ends of the spring are fixedly connected to the two sliders 42 respectively. At the same time, the spring is also sleeved on the slide rod 41, which guides the expansion and contraction of the spring, so that the spring is not easily over-twisted.

[0041] When the device is not equipped with a counterweight, the force of the elastic member 45 keeps the two sliders 42 away from each other, thereby keeping the clamping portion 2 in a position where it does not press against the truss 9. The automatic reset function of the elastic member 45 ensures that the device can be restored to a relatively stable initial state before and after each use, which is convenient for the next installation and use.

[0042] In some embodiments, see Figure 4 Two fixed pulleys 8 are rotatably arranged on the bottom surface of the truss connecting portion 1 , and the connecting ropes 44 correspond to the fixed pulleys 8 one by one and are wound around the circumferential surface of the fixed pulleys 8 .

[0043] In the process of transmitting force to the slider 42 through the connecting rope 44, the fixed pulley 8 plays a role in changing the direction of the force and reducing friction. On the one hand, the fixed pulley 8 enables the connecting rope 44 to change the direction of the force, ensuring that the reaction force component can work normally. On the other hand, the fixed pulley 8 reduces the friction of the connecting rope 44 during movement, prolongs the service life of the connecting rope 44, and improves the reliability of the device.

[0044] In some embodiments, see Figure 2 , Figure 4 and Figure 5 A safety hook 31 is fixedly provided at the bottom end of the counterweight connection part 3, and the safety hook 31 provides a convenient and safe way to hang the counterweight. Construction personnel can conveniently hang the counterweight on the safety hook 31 through a suitable connection device such as an iron chain, a rope, etc., and the operation is simple and quick. At the same time, the design of the safety hook 31 can ensure that the counterweight will not fall off accidentally during use, ensure construction safety, avoid safety accidents caused by the falling of the counterweight, and improve the safety of the entire bottom protection balance device.

[0045] In summary, compared with the prior art, the bottom protection balancing device of the bridge-building machine provided by the present invention is installed on the truss 9 of the bridge-building machine on the non-cross-line construction side. The non-cross-line construction side only relies on this bottom protection balancing device and utilizes the balancing force generated by the counterweight to meet the mechanical requirements of the balanced and symmetrical construction of the cantilever segment without the need to install a complete bottom protection device. It not only effectively avoids the idleness and waste of the bottom protection device on the non-cross-line construction side, greatly saves the cost of equipment procurement, installation and maintenance, but also improves the reasonable utilization rate of resources in the entire construction process, making the configuration of construction resources more reasonable.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A bottom protection balancing device for a bridge-building machine, installed on a truss (9) of the bridge-building machine, wherein the bridge-building machine is located on a non-crossing construction side, and is characterized in that: include: A truss connecting portion (1) sleeved on the truss (9); A clamping portion (2) is vertically slidably arranged on the truss connecting portion (1) and is located below the truss (9); the truss connecting portion (1) and the clamping portion (2) enclose a space for accommodating the truss (9); A counterweight connecting portion (3) connected to the clamping portion (2) via a reaction force component and used for hanging a counterweight; When the counterweight generates a downward force on the counterweight connection portion (3), the reaction force assembly generates an upward force on the clamping portion (2), so that the clamping portion (2) rises and presses against the truss (9).

2. A bridge-building machine bottom protection and balancing device as claimed in claim 1, characterized in that: The reaction force component comprises: A sliding rod (41) is horizontally fixedly disposed on the truss connecting portion (1) and is located below the clamping portion (2); Two sliding blocks (42) are respectively slidably mounted on the sliding rod (41); two connecting rods (43), one end of which is hinged to the clamping portion (2) and the other end of which is hinged to the slider (42), and which correspond one to one with the slider (42); Two connecting ropes (44) have one end fixed to the slider (42) and the other end fixed to the counterweight connecting portion (3), and correspond one to one with the sliders (42).

3. A bottom protection and balancing device for a bridge-building machine as claimed in claim 2, characterized in that: A limiting portion (5) is fixedly provided on each of the two sliding blocks (42), and the limiting portion (5) is horizontally slidably connected to the truss connecting portion (1); When the clamping portion (2) abuts against the truss (9), the two limiting portions (5) approach each other and abut against two sides of the truss (9) respectively; When the clamping portion (2) is separated from the truss (9), the two limiting portions (5) move away from each other and are separated from the truss (9).

4. A bottom protection and balancing device for a bridge-building machine as claimed in claim 3, characterized in that: Side rollers (6) are arranged on both sides of the truss connection part (1) for vertical rotation; When the clamping portion (2) is disengaged from the truss (9), the side roller (6) can abut against the truss (9) so that the truss connecting portion (1) is suitable for moving along the length direction of the truss (9); When the clamping portion (2) abuts against the truss (9), the limiting portion (5) abuts against the truss (9) so that a gap exists between the side roller (6) and the truss (9).

5. The bottom protection and balancing device for a bridge-building machine as claimed in claim 3 is characterized in that: An upper roller (71) is horizontally rotatably arranged above the truss (9), the upper roller (71) being vertically slidably connected to the truss connecting portion (1) via an upper roller connecting portion (72), the upper roller connecting portion (72) being in contact with the limiting portion (5); When the two limiting portions (5) move away from each other, the upper roller (71) extends from the inner top wall of the truss connecting portion (1) and abuts against the upper surface of the truss (9); When the two limiting portions (5) are brought closer to each other, the upper roller (71) is retracted into the truss connecting portion (1) so that the inner top wall of the truss connecting portion (1) overlaps the upper surface of the truss (9).

6. A bottom protection and balancing device for a bridge-building machine as claimed in claim 5, characterized in that: The limiting portion (5) has a push-up inclined surface (51), an extension portion (73) is fixedly provided on the upper roller connecting portion (72), and a matching portion (74) suitable for abutting against the push-up inclined surface (51) is fixedly provided on the extension portion (73); When the two limiting portions (5) move away from each other, the matching portion (74) slides along the pushing inclined surface (51) and descends; When the two limiting portions (5) approach each other, the matching portion (74) slides and rises along the pushing inclined surface (51).

7. A bottom protection and balancing device for a bridge-building machine as claimed in claim 6, characterized in that: The pushing inclined surface (51) is located on a side of the limiting portion (5) away from the truss (9), the limiting portion (5) is provided with a notch (52) for the extension portion (73) to pass through horizontally and slide up and down, and the matching portion (74) abuts against the outer side of the limiting portion (5).

8. The bottom protection and balancing device for a bridge-building machine as claimed in claim 2 is characterized in that: The reaction force assembly further comprises an elastic member (45) for pushing the two sliders (42) away from each other; the elastic member (45) is arranged between the two sliders (42) and sleeved on the slide rod (41).

9. A bridge-building machine bottom protection and balancing device as claimed in claim 2, characterized in that: Two fixed pulleys (8) are rotatably provided on the bottom surface of the truss connection portion (1); the connection ropes (44) correspond to the fixed pulleys (8) one by one and are wound around the circumferential surfaces of the fixed pulleys (8).

10. The bottom protection and balancing device for a bridge-building machine according to claim 1, characterized in that: A safety hook (31) is fixedly provided at the bottom end of the counterweight connecting portion (3).

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