Temperature-sensing fireproof structure with bridge main cable over-fire temperature monitoring function and construction device of temperature-sensing fireproof structure

Abstract

The invention discloses a temperature-sensing fireproof structure with a bridge main cable over-fire temperature monitoring function and a construction device of the temperature-sensing fireproof structure, and relates to the technical field of bridge main cable fireproofing. The temperature-sensing fireproof structure is composed of an outer fireproof layer, an inner fireproof layer, an irreversible thermochromic alloy sheet and a sealant layer; the inner fireproof layer is provided with a window to form a mounting groove, an alloy sheet is embedded to realize permanent recording of fire temperature, and a sealant layer guarantees sealing and bonding. The construction device comprises a first arc-shaped frame, a rotating seat and a second arc-shaped frame which are combined into a semicircular frame body for hooping the main cable, a fireproof structure is attached through a roller part, and the frame body is kept stable through a locking part. The structure solves the problem that a traditional temperature monitoring device fails in a fire, reliable temperature records are provided, the construction efficiency and quality are improved through the construction device, and safety evaluation of a bridge main cable in the fire is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of fire protection technology for bridge main cables, and more specifically to a temperature-sensing fireproof structure and its construction device that monitors the fire temperature of bridge main cables. Background Technology

[0002] As a crucial component of modern bridge structures, bridge cables directly impact the safety and stability of bridges in extreme conditions such as fires. Traditional temperature monitoring methods, such as thermocouples or resistance temperature-changing elements, rely on external power supplies and real-time data acquisition systems. However, power outages or damage to monitoring devices are common during fires, leading to the failure of temperature recording systems. In recent years, temperature-indicating coatings have been introduced into the field of cable fire protection, visually reflecting fire temperatures through color changes. However, they have a serious drawback: dense smoke generated during a fire can penetrate the inner layer through cable gaps, blackening the temperature-indicating coating and causing it to fail.

[0003] To address the shortcomings of existing technologies, this invention proposes a novel structure that incorporates an irreversible thermochromic alloy material as a temperature-indicating element. Irreversible thermochromic alloy materials are smart materials capable of undergoing permanent color changes at specific temperatures, offering the following advantages: 1. Compared to temperature-indicating coatings, irreversible thermochromic alloy materials are based on metal substrates and have extremely strong anti-pollution capabilities. Even if the surface is blackened by thick smoke, the temperature-indicating function can be restored by simple wiping.

[0004] 2. The discoloration process of the alloy is permanent and does not depend on the chemical stability of the coating, enabling it to adapt to the extreme environment in bridge fires and providing more reliable temperature monitoring.

[0005] This invention aims to solve the problem of temperature-indicating coatings failing due to dense smoke in existing technologies. By applying irreversible thermochromic alloy materials, it enables accurate recording and intuitive reading of the fire temperature of cables after a fire, providing a reliable basis for post-disaster assessment. Summary of the Invention

[0006] In view of this, the present invention provides a temperature-sensing fireproof structure and its construction device for monitoring the fire temperature of the main cable of a bridge, aiming to solve the above-mentioned technical problems.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A temperature-sensitive fireproof structure with fire-resistant monitoring capability for bridge main cables includes: an outer fireproof layer; and further includes: An inner fireproof layer is compositely attached to the inner surface of the outer fireproof layer. The inner fireproof layer has a window, which forms an installation groove with the inner surface of the outer fireproof layer. An irreversible thermochromic alloy sheet is embedded in the installation groove. The inner surface of the inner fireproof layer is coated with a sealant layer. The sealant layer is used to seal the irreversible thermochromic alloy sheet in the installation groove and to bond and position it when wrapping the main cable.

[0008] Through the above technical solution, the present invention solves the problem that the temperature-indicating coating is prone to failure due to dense smoke by compositely attaching inner and outer fireproof layers, opening a window on the inner fireproof layer to form an installation groove, embedding an irreversible thermochromic alloy sheet, and then sealing and bonding it with a sealant layer. This enables accurate recording and intuitive reading of the fire temperature of the cable after a fire, providing a reliable basis for post-disaster assessment.

[0009] Preferably, in the above-mentioned temperature-sensing fireproof structure with monitoring of the fire temperature of the main cable of a bridge, the outer fireproof layer and the inner fireproof layer are basalt cloth layers, and the sealant layer is epoxy resin sealant.

[0010] Preferably, in the above-mentioned temperature-sensing fireproof structure with bridge main cable fire temperature monitoring, the thickness of the inner fireproof layer is greater than or equal to the thickness of the irreversible thermochromic alloy sheet.

[0011] The present invention also provides a construction device for implementing the wrapping construction of the aforementioned temperature-sensing fireproof structure with bridge main cable fire temperature monitoring on the bridge main cable, comprising: A first arc-shaped frame, one end of which is provided with a first roller portion; A rotating seat is rotatably connected to the other end of the first arc-shaped frame, and a second roller portion is provided on the rotating seat; The second arc-shaped frame has one end fixedly connected to the rotating seat, and the other end of the second arc-shaped frame is provided with a third roller. The second arc-shaped frame and the first arc-shaped frame are combined to form a semi-circular frame. The semi-circular frame is fitted around the outside of the main cable, and by rotating around the circumference of the main cable, the first roller, the second roller and the third roller are used to attach the temperature-sensing fireproof structure to the outer surface of the main cable. A locking part is connected between the first arc-shaped frame and the rotating seat, and is used to restrict the first arc-shaped frame and the second arc-shaped frame from rotating to an opening angle during construction, so as to maintain the state of the semi-circular frame.

[0012] Through the above technical solution, the present invention uses a semi-circular frame formed by the combination of a first arc-shaped frame, a rotating seat, and a second arc-shaped frame to be fitted around the outside of the main cable. The temperature-sensitive fireproof structure is attached to the outer surface of the main cable using the first roller, second roller, and third roller sections. The operation is simple and can ensure that the temperature-sensitive fireproof structure is tightly attached to the main cable, improving construction efficiency and quality. The design of the locking part can effectively limit the opening angle of the arc-shaped frame, maintaining the state of the semi-circular frame during construction and ensuring the stability and reliability of the construction.

[0013] Preferably, in the above-mentioned construction device, the first roller section includes a bracket, a first roller seat, a first support shaft, and a first roller; the bracket is fixed to the end of the first arc-shaped frame, the first roller seat is rotatably connected to the bracket via a rotating shaft, the number of first support shafts is two, and the middle parts of the two first support shafts are respectively connected to both sides of the first roller seat; the number of first rollers is four, and the four first rollers are respectively rotatably connected to both sides of the two first support shafts.

[0014] Preferably, in the above-mentioned construction device, the end of the first arc-shaped frame away from the first roller portion has a U-shaped frame, and the rotating seat is rotatably connected to the opening of the U-shaped frame via a rotating shaft; the locking portion includes a sliding groove, a locking tongue, a spring, and a locking block; the sliding groove is provided on both sides inside the U-shaped frame, the two sides of the locking tongue are slidably connected to the two sliding grooves, the spring is provided in the sliding groove and connected between the locking tongue and the bottom of the sliding groove; the locking block is fixed on the rotating seat, and when the first arc-shaped frame and the second arc-shaped frame are combined to form the semi-circular frame, the locking block presses against the upper part of the locking tongue.

[0015] Preferably, in the above-mentioned construction device, a pull rope is connected to the locking tongue, the pull rope passes through the inner cavity of the first arc-shaped frame, and exits from the end of the first arc-shaped frame away from the rotating seat.

[0016] Preferably, in the above-mentioned construction device, the second roller section includes a second support shaft and a second roller. The middle part of the second support shaft is fixedly connected to the rotating seat. There are two second rollers, which are rotatably connected to both sides of the second support shaft, respectively.

[0017] Preferably, in the above-mentioned construction device, the third roller section includes a second roller seat, a third support shaft, and a third roller; the second roller seat is fixed to one end of the second arc frame away from the second roller section, the middle part of the third support shaft is connected to the second roller seat, and there are two third rollers, which are rotatably connected to both sides of the third support shaft respectively.

[0018] Preferably, in the above-mentioned construction device, both the first arc-shaped frame and the second arc-shaped frame have outwardly curved handles at their opposite ends.

[0019] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a temperature-sensing fireproof structure and its construction device with fire temperature monitoring of bridge main cables, which has the following beneficial effects: High reliability of temperature monitoring: An irreversible thermochromic alloy sheet is used as the temperature sensing element. This sheet, with a metal substrate, has strong resistance to contamination; even if blackened by dense smoke, it can regain its temperature-indicating function through wiping. The color-changing process is permanent and does not depend on the chemical stability of the coating, enabling it to adapt to the extreme environment of bridge fires and providing reliable fire temperature records for post-disaster assessment. Both the outer and inner fireproof layers use basalt fabric, a material with excellent heat insulation, high-temperature resistance, and other fire-resistant properties, effectively preventing direct damage to the main cable from fire. The sealant layer uses epoxy resin sealant, which has high bonding strength and good sealing performance, further enhancing the integrity and stability of the fireproof structure. Reasonable structural design: The thickness of the inner fireproof layer is greater than or equal to the thickness of the irreversible thermochromic alloy sheet. This not only fully protects the alloy sheet and prevents it from being damaged during construction or use, but also ensures the integrity of the fireproof structure, making the structure more stable and durable. High construction efficiency: The construction device uses a semi-circular frame formed by the combination of the first arc frame, the rotating seat, and the second arc frame to fit around the outside of the main cable. The roller part is used to attach the temperature-sensitive fireproof structure to the main cable. The operation is simple and can achieve rapid construction. The design of the locking part can effectively limit the opening angle of the arc frame, maintain the stability of the frame, and ensure the smooth progress of construction. The construction device is easy to operate: the structural design of the locking part enables stable locking and unlocking of the construction device, making operation convenient; the pull rope facilitates quick unlocking by construction personnel, enabling the opening and disassembly of the arc frame, and the device is reusable; the multiple designs of the roller part ensure that the temperature-sensitive fireproof structure fits tightly against the main cable, improving construction quality; the handle makes it easy for construction personnel to operate, making construction more labor-saving and convenient. High adaptability: The temperature-sensitive fireproof structure and its construction device are suitable for main cables of different diameters. By adjusting the size of the arc frame or the spacing of the rollers, it can meet the construction requirements of various bridge main cables. It has strong versatility and adaptability and can be widely used in various bridge projects. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0021] Figure 1 The attached figure is an exploded view of the structure of the temperature-sensing fireproof structure with fire temperature monitoring of the main cable of a bridge provided by the present invention. Figure 2 The attached figure is a structural schematic diagram of the construction device provided by the present invention; Figure 3 The attached figure is a cross-sectional view of the construction device provided by the present invention; Figure 4 The attached figure is a structural schematic diagram of the first arc-shaped frame and the rotating seat provided by the present invention; Figure 5 The attached figure is an exploded view of the structure of the first roller section provided by the present invention; Figure 6 The attached figure is a schematic diagram of the structure of the first arc-shaped frame provided by the present invention; Figure 7 The attached figure is a schematic diagram of the locking part provided by the present invention; Figure 8 The attached figure is an exploded view of the structure of the second roller section provided by the present invention; Figure 9 The attached figure is a partial structural schematic diagram of the second arc-shaped frame provided by the present invention; Figure 10 The attached figure is a schematic diagram of the structure of the second arc-shaped frame provided by the present invention; Figure 11 The attached figure is a schematic diagram of the structure of the construction device provided by the present invention, which unlocks the locking part to open the first arc-shaped frame and the second arc-shaped frame; Figure 12 The attached figure is a schematic diagram of the construction device provided by the present invention, in which a heat-sensitive fireproof structure is pasted on the main cable.

[0022] in: External fireproof layer; Inner fireproof layer; 21-Window; Irreversible thermochromic alloy sheet; Sealant layer; First arc frame; 51-First roller section; 511-Bracket; 512-First roller seat; 513-First support shaft; 514-First roller; 52-U-shaped frame; 53-Handle; Rotating seat; 61-Second roller section; 611-Second support shaft; 612-Second roller; 62-Plug; Second arc-shaped frame; 71-Third roller section; 711-Second roller seat; 712-Third support shaft; 713 Third roller; 72-Reinforcing spring; 73-Socket; Locking part; 81-Slide groove; 82-Lock tongue; 83-Spring; 84-Lock block; 85-Pull rope; Main cable. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0024] See appendix Figure 1 This invention discloses a temperature-sensing fireproof structure with fire-resistant monitoring capability for bridge main cables, comprising: an outer fireproof layer 1; and further comprising: An inner fireproof layer 2 is compositely attached to the inner surface of the outer fireproof layer 1. The inner fireproof layer 2 has a window 21. The window 21 on the inner fireproof layer 2 and the inner surface of the outer fireproof layer 1 form an installation groove. An irreversible thermochromic alloy sheet 3 is embedded in the installation groove. The inner surface of the inner fireproof layer 2 is coated with a sealant layer 4. The sealant layer 4 is used to seal the irreversible thermochromic alloy sheet 3 in the installation groove and to bond and position it when covering the main cable 9.

[0025] To further optimize the above technical solution, the outer fireproof layer 1 and the inner fireproof layer 2 are basalt fabric layers, and the sealant layer 4 is epoxy resin sealant. The basalt fabric layers of the outer fireproof layer 1 and the inner fireproof layer 2 have good fire resistance and durability, effectively protecting the main cable; the epoxy resin sealant layer 4 has high bonding strength and good sealing performance, ensuring the stability of the irreversible thermochromic alloy sheet and the integrity of the temperature-sensitive fireproof structure.

[0026] To further optimize the above technical solution, the thickness of the inner fireproof layer 2 is greater than or equal to the thickness of the irreversible thermochromic alloy sheet 3. This allows the inner fireproof layer 2 to better protect the alloy sheet, preventing damage during construction or use, while ensuring the integrity and fire resistance of the temperature-sensitive fireproof structure.

[0027] In this embodiment, the irreversible thermochromic alloy sheet 3, such as Ti, forms a TiO2 film with a thickness of about 30-80 nm at 250-300 degrees Celsius, which appears as blue-purple or brownish-yellow. Example

[0028] See appendix Figure 2 and attached Figure 3To facilitate the construction of the temperature-sensitive fireproof structure in Embodiment 1, this embodiment provides a construction device for covering the main cable 9 of the bridge with the temperature-sensitive fireproof structure equipped with bridge main cable fire temperature monitoring, as described in Embodiment 1. The device includes: The first arc-shaped frame 5 has a first roller portion 51 at one end; Rotary seat 6 is rotatably connected to the other end of the first arc frame 5, and a second roller part 61 is provided on the rotating seat 6; The second arc-shaped frame 7 has one end fixedly connected to the rotating seat 6, and the other end of the second arc-shaped frame 7 is provided with a third roller part 71. The second arc-shaped frame 7 and the first arc-shaped frame 5 are combined to form a semi-circular frame. The semi-circular frame is fitted around the outside of the main cable 9, and by rotating around the circumference of the main cable 9, the temperature-sensing fireproof structure is attached to the outer surface of the main cable 9 using the first roller part 51, the second roller part 61, and the third roller part 71. Figure 12 As shown; The locking part 8 is connected between the first arc frame 5 and the rotating seat 6, and is used to restrict the first arc frame 5 and the second arc frame 7 from rotating to the opening angle during construction, so as to keep them in the state of a semi-circular frame.

[0029] See appendix Figure 4 and attached Figure 5 The first roller section 51 includes a bracket 511, a first roller seat 512, a first support shaft 513, and first rollers 514. The bracket 511 is fixed to the end of the first arc-shaped frame 5. The first roller seat 512 is rotatably connected to the bracket 511 via a rotating shaft. There are two first support shafts 513, with their middle parts connected to both sides of the first roller seat 512. There are four first rollers 514, which are rotatably connected to both sides of the two first support shafts 513. This structural design of the first roller section 51 allows the rollers to evenly attach the heat-sensitive fireproof structure to the surface of the main cable 9, improving construction accuracy, reducing problems such as loose adhesion of the heat-sensitive fireproof structure due to uneven roller force, and ensuring construction quality.

[0030] See appendix Figure 6 To be continued Figure 8The first arc-shaped frame 5 has a U-shaped frame 52 at the end away from the first roller part 51. The rotating seat 6 is rotatably connected to the opening of the U-shaped frame 52 via a rotating shaft. The locking part 8 includes a sliding groove 81, a locking tongue 82, a spring 83, and a locking block 84. The sliding groove 81 is located on both sides inside the U-shaped frame 52. The two sides of the locking tongue 82 are slidably connected to the two sliding grooves 81. The spring 83 is located inside the sliding groove 81 and is connected between the locking tongue 82 and the bottom of the groove 81. The locking block 84 is fixed on the rotating seat 6, and when the first arc-shaped frame 5 and the second arc-shaped frame 7 are combined to form a semi-circular frame, the locking block 84 presses against the upper part of the locking tongue 82. This achieves stable locking and unlocking functions for the first arc-shaped frame 5 and the second arc-shaped frame 7 during construction. The operation is convenient and can effectively prevent the arc-shaped frame from accidentally opening during construction, leading to construction failure or damage to the temperature-sensitive fireproof structure, thus improving the safety and reliability of construction.

[0031] To further optimize the above technical solution, a pull rope 85 is connected to the locking tongue 82. The pull rope 85 passes through the inner cavity of the first arc-shaped frame 5 and exits from the end of the first arc-shaped frame 5 away from the rotating seat 6. This allows construction personnel to quickly unlock the locking tongue 82 from the outside by pulling the rope 85, thereby opening the first arc-shaped frame 5 and the second arc-shaped frame 7. This facilitates the disassembly and reuse of the construction device, improving the convenience and efficiency of construction.

[0032] To further optimize the above technical solution, the second roller section 61 includes a second support shaft 611 and a second roller 612. The middle part of the second support shaft 611 is fixedly connected to the rotating seat 6. There are two second rollers 612, which are rotatably connected to both sides of the second support shaft 611. This structural design of the second roller section 61 enables the second roller 612 to rotate stably and provides good support and guidance for the temperature-sensitive fireproof structure during construction, ensuring the adhesion of the temperature-sensitive fireproof structure to the surface of the main cable 9. Together with the first roller section 51 and the third roller section 71, it improves the construction quality and efficiency.

[0033] See appendix Figure 10 The third roller section 71 includes a second roller seat 711, a third support shaft 712, and a third roller 713. The second roller seat 711 is fixed to the end of the second arc-shaped frame 7 away from the second roller section 61. The middle part of the third support shaft 712 is connected to the second roller seat 711. There are two third rollers 713, which are rotatably connected to both sides of the third support shaft 712. This structural design of the third roller section 71, with the third roller 713, further ensures the uniformity and tightness of the heat-sensitive fireproof structure attached to the surface of the main cable 9. Working in conjunction with the first roller section 51 and the second roller section 61, it allows the heat-sensitive fireproof structure to better adapt to the shape and surface characteristics of the main cable 9, improving the precision of construction.

[0034] To further optimize the above technical solution, both ends of the first arc-shaped frame 5 and the second arc-shaped frame 7 have outwardly curved handles 53. This facilitates the operation and control of the construction equipment by construction personnel during construction, making construction more labor-saving and convenient. It also facilitates the installation, disassembly, and transportation of the construction equipment, thereby improving construction efficiency.

[0035] When the pull rope 85 is pulled to unlock the locking tongue 82, the first arc-shaped bracket 5 and the second arc-shaped bracket 7 open, enabling disassembly. Figure 11 As shown.

[0036] The second arc-shaped frame 7 can be made into a split structure, connected by reinforced springs 72 to achieve elastic cushioning.

[0037] To enable detachability, one end of the second arc-shaped frame 7 has a socket 73, and the rotating seat 6 has a plug 62 that mates with it. After the plug 62 and the socket 73 are plugged in, they are fastened together by bolts.

[0038] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0039] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A temperature-sensing fireproof structure with fire-sensing temperature monitoring capability for bridge main cables, comprising: The outer fireproof layer (1) is characterized in that it further includes: An inner fireproof layer (2) is compositely attached to the inner surface of the outer fireproof layer (1). The inner fireproof layer (2) has a window (21). The window (21) on the inner fireproof layer (2) and the inner surface of the outer fireproof layer (1) form an installation groove. An irreversible thermochromic alloy sheet (3) is embedded in the installation groove. The inner surface of the inner fireproof layer (2) is coated with a sealant layer (4). The sealant layer (4) is used to seal the irreversible thermochromic alloy sheet (3) in the installation groove and to bond and position the main cable (9) when it is wrapped.

2. A temperature-sensing fireproof structure with fire-sensing temperature monitoring for bridge main cables according to claim 1, characterized in that, The outer fireproof layer (1) and the inner fireproof layer (2) are basalt cloth layers, and the sealant layer (4) is epoxy resin sealant.

3. A temperature-sensing fireproof structure with fire-sensing temperature monitoring for bridge main cables according to claim 1, characterized in that, The thickness of the inner fireproof layer (2) is greater than or equal to the thickness of the irreversible thermochromic alloy sheet (3).

4. A construction device for covering the main cable (9) of a bridge with a temperature-sensing fireproof structure equipped with bridge main cable fire temperature monitoring as described in any one of claims 1-3, characterized in that, include: The first arc frame (5) has a first roller part (51) at one end. Rotary seat (6), which is rotatably connected to the other end of the first arc frame (5), and the rotating seat (6) is provided with a second roller part (61). The second arc frame (7) has one end fixedly connected to the rotating seat (6), and the other end of the second arc frame (7) is provided with a third roller part (71). The second arc frame (7) and the first arc frame (5) are combined to form a semi-circular frame. The semi-circular frame is fitted around the outside of the main cable (9), and by rotating around the circumference of the main cable (9), the first roller part (51), the second roller part (61) and the third roller part (71) are used to attach the temperature-sensing fireproof structure to the outer surface of the main cable (9). The locking part (8) is connected between the first arc frame (5) and the rotating seat (6) and is used to restrict the first arc frame (5) and the second arc frame (7) from rotating to the opening angle during construction, so as to maintain the state of the semi-circular frame.

5. A construction device according to claim 4, characterized in that, The first roller section (51) includes a bracket (511), a first roller seat (512), a first support shaft (513), and a first roller (514). The bracket (511) is fixed to the end of the first arc frame (5). The first roller seat (512) is rotatably connected to the bracket (511) through a rotating shaft. There are two first support shafts (513), and the middle parts of the two first support shafts (513) are respectively connected to the two sides of the first roller seat (512). There are four first rollers (514), and the four first rollers (514) are rotatably connected to the two sides of the two first support shafts (513).

6. A construction device according to claim 4, characterized in that, The first arc frame (5) has a U-shaped frame (52) at one end away from the first roller part (51). The rotating seat (6) is rotatably connected to the opening of the U-shaped frame (52) through a rotating shaft. The locking part (8) includes a sliding groove (81), a locking tongue (82), a spring (83), and a locking block (84). The sliding groove (81) is located on both sides inside the U-shaped frame (52). The two sides of the locking tongue (82) are slidably connected to the two sliding grooves (81). The spring (83) is located in the sliding groove (81) and connected between the locking tongue (82) and the bottom of the sliding groove (81). The locking block (84) is fixed on the rotating seat (6). When the first arc frame (5) and the second arc frame (7) are combined to form the semi-circular frame, the locking block (84) presses against the upper part of the locking tongue (82).

7. A construction device according to claim 6, characterized in that, A pull rope (85) is connected to the latch (82), the pull rope (85) passes through the inner cavity of the first arc frame (5) and exits from the end of the first arc frame (5) away from the rotating seat (6).

8. A construction device according to claim 4, characterized in that, The second roller section (61) includes a second support shaft (611) and a second roller (612). The middle part of the second support shaft (611) is fixedly connected to the rotating seat (6). There are two second rollers (612), which are rotatably connected to both sides of the second support shaft (611).

9. A construction device according to claim 4, characterized in that, The third roller section (71) includes a second roller seat (711), a third support shaft (712), and a third roller (713); the second roller seat (711) is fixed to one end of the second arc frame (7) away from the second roller section (61), the middle part of the third support shaft (712) is connected to the second roller seat (711), and there are two third rollers (713), which are rotatably connected to both sides of the third support shaft (712).

10. A construction device according to claim 4, characterized in that, The first arc frame (5) and the second arc frame (7) each have outwardly curved handles (53) at their opposite ends.

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