Negative moment tension hole protection device

Abstract

The present application relates to the technical field of negative bending moment tension hole protection, in particular to a negative bending moment tension hole protection device. The device body in the embodiment can be installed by sequentially rotating and connecting a plurality of plate bodies and finally connecting the first plate body and the fourth plate body by a connecting rod. The whole process is convenient to operate and can be better matched with the protection bottom plate. Each plate body only needs to be rotated to the corresponding protection bottom plate, that is, the protection bottom plate can better serve as a rotation reference to indicate to the operator, so as to avoid a large angle deviation between adjacent plate bodies, which may make it difficult to connect the first plate body and the fourth plate body by the connecting rod.

Description

Technical Field

[0001] This invention relates to the field of negative bending moment tensioning hole protection technology, and more specifically, to a negative bending moment tensioning hole protection device. Background Technology

[0002] The negative bending moment tensioning holes of prestressed small box girders, as reserved holes for the continuous construction of prestressed small box girder bridges, are exposed to the construction site for a long time during the erection of the box girders. If effective measures are not taken to protect them, they will pose a hidden danger to the safety of box girder erection operations and bridge construction workers.

[0003] Traditional construction techniques often use covered waste formwork for protection. This protective measure not only fails to effectively warn construction workers, but also often results in insufficient load-bearing capacity when workers step on it, causing workers to fall into the hole and suffer injuries. Summary of the Invention

[0004] This invention provides a protective device for negative bending moment tensioning holes, which can overcome some or all the defects of the prior art.

[0005] According to the present invention, a protective device for a negative bending moment tensioning hole includes a device body, which includes a first plate, a second plate, a third plate, and a fourth plate. The first plate, the second plate, the third plate, and the fourth plate are connected in pairs and together form a protective ring. The protective ring is used to be placed at the negative bending moment tensioning hole. The first plate and the second plate, as well as the second plate and the third plate, are movably connected in pairs by hinges. A connecting rod is provided between the first plate and the fourth plate for fixing the first plate and the fourth plate together.

[0006] Preferably, the device body also includes a ring-shaped protective base plate, which is used to be placed at the opening of the negative bending moment tensioning hole; the protective base plate includes a first base plate, a second base plate, a third base plate and a fourth base plate connected in pairs.

[0007] Preferably, the first base plate, the second base plate, the third base plate, and the fourth base plate are respectively used to correspond to the first plate body, the second plate body, the third plate body, and the fourth plate body. The first base plate, the second base plate, the third base plate, and the fourth base plate all include a base plate body. The base plate body includes a vertical base plate and a horizontal base plate arranged orthogonally to each other, and a first right angle portion and a second right angle portion are formed between the vertical base plate and the horizontal base plate.

[0008] Preferably, the first right-angled portion is used to abut against the upper edge of the opening of the negative bending moment tensioning hole, and the second right-angled portion is used to abut against the bottom corner of the first plate, the second plate, the third plate, or the fourth plate.

[0009] Preferably, a positioning plate is provided on one side of the first plate away from the negative bending moment tensioning hole, and a clamping mechanism is provided on the outside of the positioning plate to clamp the positioning plate against the protective baffle.

[0010] Preferably, the clamping mechanism includes an arc-shaped plate, the bottom end of which is fixedly connected to the bottom of the positioning pressure plate. Mounting seats are provided on both sides of the arc-shaped plate, and the side walls of the arc-shaped plate are connected to the mounting seats through a pivot. A torsion spring is provided at the pivot, which is used to maintain the tendency of the arc-shaped plate to drive the positioning pressure plate to press the first plate against the protective baffle. A pedal is formed at the top of the arc-shaped plate, which is used for foot pedaling to release the pressure between the first plate and the protective baffle.

[0011] Preferably, the positioning plate has two mounting plates arranged vertically on one side near the second plate. Each mounting plate has an adjustment through hole for mounting an adjustment rod. The lower part of the adjustment rod is threaded to the adjustment through hole located on the lower side. A first side plate is connected to the side wall of the adjustment rod. The first side plate is used to abut against the outer wall of the second plate. The adjustment rod is used to rotate to adjust the angle between the second plate and the first plate.

[0012] Preferably, the top wall of the first plate is provided with a mounting shaft, the first end of the connecting rod is movably connected to the mounting shaft, and the top wall of the fourth plate is provided with a positioning hole for fastening the second end of the connecting rod.

[0013] Preferably, an adjusting sleeve is provided at the middle of the connecting rod, and the portions of the connecting rod located on both sides of the adjusting sleeve form a first rod body and a second rod body respectively. The first rod body and the second rod body are separated, and a first thread and a second thread are formed on the side of the first rod body and the second rod body near the adjusting sleeve respectively. The first thread and the second thread have opposite directions of rotation, and the first thread and the second thread are threadedly connected to both ends of the adjusting sleeve respectively. The adjusting sleeve is used to manually rotate to adjust the included angle between the first plate body and the second plate body.

[0014] The present invention also provides a method for protecting a negative bending moment tensioning hole, which is based on the aforementioned negative bending moment tensioning hole protection device, and specifically includes the following steps:

[0015] Step S1: First, fix the first plate at the negative bending moment tensioning hole.

[0016] Step S2: Rotate the second plate relative to the first plate to form a perpendicular shape;

[0017] Step S3: Rotate the third plate relative to the second plate to make it perpendicular;

[0018] Step S4: Rotate the fourth plate relative to the third plate and fasten the first plate and the fourth plate together using the connecting rod;

[0019] Step S5: The first plate, the second plate, the third plate and the fourth plate together form a protective ring to protect the negative bending moment tensioning hole. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the device body in Example 1;

[0021] Figure 2 This is a schematic diagram of the structure of the device body in Example 2;

[0022] Figure 3 for Figure 2 Schematic diagram of the structure of the protective base plate;

[0023] Figure 4 for Figure 3 Schematic diagram of the structure of the midsole plate body;

[0024] Figure 5 This is a schematic diagram of the structure of the first plate in Example 3;

[0025] Figure 6 This is a schematic diagram of the protective plate section in Example 3;

[0026] Figure 7 This is a schematic diagram of the structure of the device body in Example 4;

[0027] Figure 8 for Figure 7 Enlarged view of point A in the middle;

[0028] Figure 9 This is a schematic diagram of the protective plate section in Example 5;

[0029] Figure 10 This is a schematic diagram of the structure of the device body in Example 6;

[0030] Figure 11 for Figure 10 Enlarged view of point B in the middle;

[0031] Figure 12 This is a structural schematic diagram of the device body from another perspective in Embodiment 6;

[0032] Figure 13 for Figure 12 Enlarged view of point C in the middle;

[0033] Figure 14 This is a schematic diagram of the structure of the device body in Example 7;

[0034] Figure 15 for Figure 14 A schematic diagram of the connecting rod in the middle. Detailed Implementation

[0035] To further understand the content of this invention, the invention will be described in detail with reference to the embodiments. It should be understood that the embodiments are merely illustrative and not limiting of the invention.

[0036] Example 1

[0037] This embodiment provides a protective device, which includes a device body 100. The device body 100 includes a protective plate portion, which includes a first plate 110, a second plate 120, a third plate 130, and a fourth plate 140 connected in sequence. The first plate 110, the second plate 120, the third plate 130, and the fourth plate 140 are connected in pairs and together form a protective ring. In this embodiment, the protective ring can be placed at bridge openings or negative bending moment tensioning holes to protect the openings and effectively prevent workers from stepping into the openings.

[0038] In this embodiment, the first plate 110 and the third plate 130 use 160cm*50cm A-panel. The second plate 120 and the fourth plate 140 use 120cm*50cm B-panel. Each component is welded together from four 3*3cm rectangular steel pipes as the main frame. The A-panel is 160cm long and 50cm high, and the B-panel is 120cm long and 50cm high, meeting the requirement of protecting the largest hole (145cm*110cm) on both sides. A single-sided spray-painted thin iron sheet is installed on the outside of the frame with rivets. The spray-painted content is safety operating procedures and promotional slogans.

[0039] Example 2

[0040] Similar to Embodiment 1, the difference between this embodiment and Embodiment 1 is that the device body 100 in this embodiment also includes a ring-shaped protective base plate 200, which is used to be placed at the opening of the bridge hole; the protective base plate 200 includes a first base plate 210, a second base plate 220, a third base plate 230 and a fourth base plate 240 connected in pairs.

[0041] In this embodiment, the first base plate 210, the second base plate 220, the third base plate 230 and the fourth base plate 240 are respectively used to correspond to the first plate body 110, the second plate body 120, the third plate body 130 and the fourth plate body 140. The first base plate 210, the second base plate 220, the third base plate 230 and the fourth base plate 240 all include a base plate body 400. The base plate body 400 includes a vertical base plate 410 and a horizontal base plate 420 arranged orthogonally to each other. A first right angle portion 430 and a second right angle portion 440 are formed between the vertical base plate 410 and the horizontal base plate 420.

[0042] In this embodiment, the first right-angle portion 430 is used to abut against the upper edge of the opening of the bridge hole, and the second right-angle portion 440 is used to abut against the bottom corner of the first plate 110, the second plate 120, the third plate 130, or the fourth plate 140.

[0043] Specifically, during the use of the device body 100, the operator can choose to first install the protective base plate 200 through the first right angle portion 430 at the hole, so as to facilitate the subsequent installation of the first plate 110, the second plate 120, the third plate 130 and the fourth plate 140. It can be understood that the protective base plate 200 can separate the hole from the protective plate part to prevent the protective plate part from moving and exposing part of the hole. On the other hand, since the protective plate part in this embodiment is composed of the first plate 110, the second plate 120, the third plate 130 and the fourth plate 140, the pre-installed protective base plate 200 can also provide a more accurate installation position for each plate (each plate can be placed directly on the corresponding protective base plate 200), thereby ensuring a stable connection between adjacent plates and ensuring the effective protection of the entire device body 100.

[0044] Example 3

[0045] Similar to Embodiment 2, the difference between this embodiment and Embodiment 2 is that, in this embodiment, steel plates 510 are welded to both side walls of the first plate 110, the second plate 120, the third plate 130 and the fourth plate 140, and round holes 520 are opened in the steel plates 510. The first plate 110, the second plate 120, the third plate 130 and the fourth plate 140 are fastened to each other through the round holes 520 in the steel plates 510 and the use of pins.

[0046] Panel A frame uprights (perpendicular to the panel direction) are welded with 3*3cm, 3mm thick steel plates 510 at the top and bottom thirds. An 8mm diameter round steel upright, 5cm high, is placed at the center of each 510 steel plate. Panel B frame uprights (parallel to the panel direction) are welded with 3*3cm, 3mm thick steel plates 510 at the top and bottom thirds. A 10mm diameter round hole 520 is placed at the center of each 510 steel plate.

[0047] In this embodiment, the protective panels are all made of 3*3cm rectangular steel pipes and thin railway single-sided powder-coated panels, which are lightweight and easy to transport and install. Furthermore, the panels in this device employ a modular design, allowing each panel to be independently disassembled and installed, facilitating transportation and reuse, and reducing damage. Adjacent panels are assembled using snap-fit ​​joints, making installation and disassembly convenient and ensuring good stability. Safety warning slogans can also be sprayed on the outside of the panels for eye-catching safety promotion. Moreover, this device can be manufactured once and used multiple times, is easy to install and disassemble, and provides excellent protection.

[0048] Example 4

[0049] Similar to Embodiment 3, the difference between this embodiment and Embodiment 3 is that in this embodiment, a connecting rod 710 is provided between the first plate 110 and the second plate 120 and between the first plate 110 and the fourth plate 140. The connecting rod 710 is used to cooperate with the round hole 520 and the pin to adjust the included angle between the first plate 110 and the second plate 120.

[0050] The first end of the connecting rod 710 is connected to the top wall of the first plate 110. The top wall of the first plate 110 is provided with a mounting shaft 810. The first end of the connecting rod 710 is movably connected to the mounting shaft 810. The top wall of the second plate 120 is provided with a positioning hole 820, which is used to fasten the second end of the connecting rod 710.

[0051] An adjusting sleeve 830 is provided at the middle of the connecting rod 710. The portions of the connecting rod 710 located on both sides of the adjusting sleeve 830 form a first rod body 711 and a second rod body 712, respectively. The first rod body 711 and the second rod body 712 are separated. A first thread 713 and a second thread 714 are formed on the side of the first rod body 711 and the second rod body 712 near the adjusting sleeve 830, respectively. The first thread 713 and the second thread 714 have opposite directions of rotation. The first thread 713 and the second thread 714 are threadedly connected to both ends of the adjusting sleeve 830, respectively. The adjusting sleeve 830 is used for manual rotation to adjust the included angle between the first plate 110 and the second plate 120 (the fourth plate 140).

[0052] Specifically, when using the device body 100 in this embodiment, the specific steps are as follows:

[0053] Step S1: Install the first plate 110 at the bridge hole;

[0054] Step S2: Then, the second plate 120 and the fourth plate 140 are fastened to the first plate 110 using pins.

[0055] Step S3: Finally, fasten the third plate 130 to the second plate 120 and the fourth plate 140 with pins.

[0056] Step S4: The first plate 110, the second plate 120, the third plate 130 and the fourth plate 140 together form a protective ring and protect the bridge opening.

[0057] Understandably, the operator can first fasten the first plate 110 to the second plate 120 and the fourth plate 140 using the pin in Embodiment 3; and then connect the first plate 110 to the second plate 120 and the fourth plate 140 using the connecting rod 710.

[0058] The function of connecting rod 710 is:

[0059] Firstly, the first plate 110 and the second plate 120 (fourth plate 140) are only connected by a pin, which may cause shaking and other instability. In this embodiment, the first plate 110 and the second plate 120 (fourth plate 140) can be further positioned and connected by the positioning hole 820 at the connecting rod 710 to ensure the stability of the entire protective plate and prevent deformation and displacement at the work site.

[0060] Secondly, in this embodiment, when the device body 100 is in use, after the first plate 110 is connected to the second plate 120 and the fourth plate 140, due to the connection via pins, there is a tendency for angular deviation between the second plate 120 and the fourth plate 140, making it difficult to achieve a good connection with the third plate 130. This results in the steel plate 510 at the third plate 130 being difficult to position and connect with the second plate 120 (fourth plate 140). At this time, the operator can finely adjust the angle between the first plate 110 and the second plate 120 (fourth plate 140) by rotating the sleeve and engaging the thread, thereby enabling the steel plate 510 at the third plate 130 to be better aligned with the second plate 120 (fourth plate 140), thus facilitating the operator to install and position the third plate 130 using the pins.

[0061] Thirdly, after the first plate 110, the second plate 120, the third plate 130, and the fourth plate 140 are all installed, the operator can rotate the adjusting sleeve 830 to pull the first plate 110 and the second plate 120 (fourth plate 140) closer to each other, so as to press each plate onto the vertical base plate 410 of the protective base plate 200, thereby further improving the stability of the entire protective plate section. That is, the protective base plate 200 installed at the hole can not only provide an installation position for each plate, but also serve as a fixing component to cooperate with each plate to be pressed and positioned.

[0062] Example 5

[0063] Similar to Embodiment 2, the difference between this embodiment and Embodiment 2 is that, in this embodiment, the first plate 110 and the second plate 120, as well as the second plate 120 and the third plate 130, are movably connected in pairs by hinges 910; a connecting rod 710 is provided between the first plate 110 and the fourth plate 140, and the connecting rod 710 is used to fix the first plate 110 and the fourth plate 140.

[0064] Specifically, when the device body 100 in this embodiment is used, the following steps are included:

[0065] Step S1: First, fix the first plate 110 at the negative bending moment tensioning hole.

[0066] Step S2: Rotate the second plate 120 relative to the first plate 110 to form a perpendicular position;

[0067] Step S3: Rotate the third plate 130 relative to the second plate 120 to make it perpendicular;

[0068] Step S4: Rotate the fourth plate 140 relative to the third plate 130, and fasten the first plate 110 and the fourth plate 140 together through the connecting rod 710.

[0069] Step S5: The first plate 110, the second plate 120, the third plate 130 and the fourth plate 140 together form a protective ring to protect the hole.

[0070] Understandably, the device body 100 in this embodiment can be installed by sequentially rotating and connecting multiple plates, and finally connecting the first plate 110 and the fourth plate 140 through the connecting rod 710. The whole process is convenient to operate and can be better coordinated with the protective base plate 200. Each plate only needs to be rotated to the corresponding protective base plate 200. That is, the protective base plate 200 can better serve as a reference for rotation to guide the operator, so as to avoid a large deviation in the included angle between adjacent plates, which would make it difficult to connect the first plate 110 and the fourth plate 140 through the connecting rod 710.

[0071] Example 6

[0072] Similar to Embodiment 5, the difference between this embodiment and Embodiment 5 is that: in this embodiment, a positioning pressure plate 1010 is provided on one side of the far hole of the first plate 110, and a pressing mechanism is provided on the outside of the positioning pressure plate 1010. The pressing mechanism is used to press the positioning pressure plate 1010 against the protective baffle.

[0073] The clamping mechanism includes an arc-shaped plate 1020, the bottom end of which is fixedly connected to the bottom of the positioning pressure plate 1010. Mounting seats 1110 are provided on both sides of the arc-shaped plate 1020. The side walls of the arc-shaped plate 1020 are connected to the mounting seats 1110 through a pivot. A torsion spring 1120 is provided at the pivot. The torsion spring 1120 is used to maintain the tendency of the arc-shaped plate 1020 to drive the positioning pressure plate 1010 to press the first plate 110 against the protective baffle. A foot pedal 1130 is formed at the top of the arc-shaped plate 1020. The foot pedal 1130 is used to step on the pedal to release the clamping between the first plate 110 and the protective baffle.

[0074] Specifically, in this embodiment, when using the device body 100, the first plate 110 must be installed first, and then the second plate 120, the third plate 130, and the fourth plate 140 are rotated and connected in sequence. Therefore, the first plate 110 needs to be optimally positioned to ensure the normal progress of the subsequent connection process. In this embodiment, the positioning pressure plate 1010 in the clamping mechanism can cooperate with the protective base plate 200 to clamp and position the first plate 110. When installing the first plate 110, the operator only needs to... The positioning plate 1010 needs to be unscrewed by stepping on the pedal 1130, and then the first plate 110 is pressed against the protective base plate 200. After that, the pedal 1130 is released, and under the action of the torsion spring 1120, the positioning plate 1010 springs back and presses the first plate 110 against the first base plate 210 of the protective base plate 200, thereby better maintaining the accurate and stable position of the first plate 110, so as to ensure that the rotation positions of the subsequent second plate 120, third plate 130 and fourth plate 140 can be aligned in sequence.

[0075] In addition, when it is necessary to dismantle the device, the operator only needs to step on the pedal 1130 to release the first plate 110 from its position and move the entire device body 100 out. The operation is simple and convenient.

[0076] Two mounting plates 1310 are formed on one side of the positioning plate 1010 near the second plate 120, arranged vertically. Each mounting plate 1310 has an adjustment through hole for mounting an adjustment rod 1320. The lower part of the adjustment rod 1320 is threadedly connected to the adjustment through hole located on the lower side. A first side plate 1330 is connected to the side wall of the adjustment rod 1320. The first side plate 1330 is used to abut against the outer wall of the second plate 120. The adjustment rod 1320 is used to rotate to adjust the angle between the second plate 120 and the first plate 110.

[0077] Furthermore, after the first plate 110 is installed, the second plate 120 needs to be rotated and moved. During the rotation of the second plate 120, it can be first placed against the first side plate 1330 (the first side plate 1330 is kept parallel to the first plate 110 at this time) as the first position. Then, it is only necessary to rotate the adjusting rod 1320. The rotation of the adjusting rod 1320 drives the first side plate 1330 to rotate, which in turn drives the second plate 120 to rotate. When the second plate 120 is rotated to the second base plate 220 of the protective base plate 200, it can be confirmed that the rotation is in place. After that, continue to rotate the adjusting rod 1320 so that the second plate 120 is better pressed against the protective base plate 200, so that the position of the second plate 120 can also be better maintained and stable.

[0078] Example 7

[0079] Similar to Embodiment 6, the difference between this embodiment and Embodiment 6 is that, in this embodiment, the top wall of the first plate 110 is provided with a mounting shaft 810, the first end of the connecting rod 710 is movably connected to the mounting shaft 810, and the top wall of the fourth plate 140 is provided with a positioning hole 820, which is used to be fastened to the second end of the connecting rod 710.

[0080] An adjusting sleeve 830 is provided at the middle of the connecting rod 710. The portions of the connecting rod 710 located on both sides of the adjusting sleeve 830 form a first rod body 711 and a second rod body 712, respectively. The first rod body 711 and the second rod body 712 are separated. A first thread 713 and a second thread 714 are formed on the side of the first rod body 711 and the second rod body 712 near the adjusting sleeve 830, respectively. The first thread 713 and the second thread 714 have opposite directions of rotation. The first thread 713 and the second thread 714 are threadedly connected to both ends of the adjusting sleeve 830, respectively. The adjusting sleeve 830 is used for manual rotation to adjust the included angle between the first plate 110 and the second plate 120.

[0081] Specifically, during use, after the second plate 120 and the third plate 130 have both rotated, the fourth plate 140 continues to rotate to connect with the first plate 110. However, since there may be deviations when the second plate 120 and the third plate 130 rotate, the positioning hole 820 at the fourth plate 140 may not be able to be aligned with the second end of the connecting rod 710. At this time, the operator can adjust the position of the second rod 712 near the fourth plate 140 by rotating the adjusting sleeve 830, thereby offsetting the possible deviations that may exist during the rotation of the second plate 120 and the third plate 130, so that the operator can position and connect the first rod 711 and the fourth rod.

[0082] It is readily understood that those skilled in the art can combine, split, or reorganize the embodiments provided in this application to obtain other embodiments, all of which do not exceed the protection scope of this application.

[0083] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the embodiments shown are only part of the embodiments of the present invention. The actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A protective device for negative bending moment tensioning holes, characterized in that, The device includes a main body (100), which includes a first plate (110), a second plate (120), a third plate (130), and a fourth plate (140). The first plate (110), the second plate (120), the third plate (130), and the fourth plate (140) are connected in pairs and together form a protective ring. The protective ring is used to be placed at the negative bending moment tensioning hole. The first plate (110) and the second plate (120) and the second plate (120) and the third plate (130) are movably connected in pairs by hinges (910). A connecting rod (710) is provided between the first plate (110) and the fourth plate (140). The connecting rod (710) is used to fix the first plate (110) and the fourth plate (140). The device body (100) also includes a ring-shaped protective base plate (200), which is used to be placed at the opening of the negative bending moment tensioning hole; the protective base plate (200) includes a base plate body (400), which includes a vertical base plate (410) and a horizontal base plate (420) arranged orthogonally to each other. The first plate (110) is provided with a positioning pressure plate (1010) on the side away from the negative bending moment tensioning hole. The positioning pressure plate (1010) is provided with a clamping mechanism on the outside. The clamping mechanism is used to clamp the positioning pressure plate (1010) against the protective base plate (200). The clamping mechanism includes an arc plate (1020), the bottom end of which is fixedly connected to the bottom of the positioning pressure plate (1010). Mounting seats (1110) are provided on both sides of the arc plate (1020). The side walls of the arc plate (1020) are connected to the mounting seats (1110) via a pivot. A torsion spring (1120) is provided at the pivot. The torsion spring (1120) is used to maintain the tendency of the arc plate (1020) to drive the positioning pressure plate (1010) to press the first plate (110) onto the protective base plate (200). A foot pedal (1130) is formed at the top of the arc plate (1020). The foot pedal (1130) is used to step on the plate to release the clamping between the first plate (110) and the protective baffle.

2. The negative bending moment tensioning hole protection device according to claim 1, characterized in that: The protective base plate (200) includes a first base plate (210), a second base plate (220), a third base plate (230), and a fourth base plate (240) that are connected in pairs.

3. The negative bending moment tensioning hole protection device according to claim 2, characterized in that: The first base plate (210), the second base plate (220), the third base plate (230) and the fourth base plate (240) are respectively used to correspond to the first plate body (110), the second plate body (120), the third plate body (130) and the fourth plate body (140). The first base plate (210), the second base plate (220), the third base plate (230) and the fourth base plate (240) all include a base plate body (400). A first right angle portion (430) and a second right angle portion (440) are formed between the vertical base plate (410) and the horizontal base plate (420).

4. The negative bending moment tensioning hole protection device according to claim 3, characterized in that: The first right-angled part (430) is used to abut against the upper edge of the opening of the negative bending moment tensioning hole, and the second right-angled part (440) is used to abut against the bottom corner of the first plate (110), the second plate (120), the third plate (130), or the fourth plate (140).

5. The negative bending moment tensioning hole protection device according to claim 1, characterized in that: The positioning plate (1010) has two mounting plates (1310) arranged vertically on one side near the second plate (120). Each of the two mounting plates (1310) has an adjustment through hole for mounting an adjustment rod (1320). The lower part of the adjustment rod (1320) is threadedly connected to the adjustment through hole located on the lower side. A first side plate (1330) is connected to the side wall of the adjustment rod (1320). The first side plate (1330) is used to abut against the outer wall of the second plate (120). The adjustment rod is used to rotate to adjust the angle between the second plate (120) and the first plate (110).

6. The negative bending moment tensioning hole protection device according to claim 2, characterized in that: The top wall of the first plate (110) is provided with an installation shaft (810), and the first end of the connecting rod (710) is movably connected to the installation shaft (810). The top wall of the fourth plate (140) is provided with a positioning hole (820), which is used to be fastened to the second end of the connecting rod (710).

7. The negative bending moment tensioning hole protection device according to claim 1, characterized in that: An adjusting sleeve (830) is provided at the middle of the connecting rod (710). The parts of the connecting rod (710) located on both sides of the adjusting sleeve (830) form a first rod body (711) and a second rod body (712), respectively. The first rod body (711) and the second rod body (712) are separated. The first rod body (711) and the second rod body (712) near the adjusting sleeve (830) are respectively formed with a first thread (713) and a second thread (714). The first thread (713) and the second thread (714) have opposite directions of rotation. The first thread (713) and the second thread (714) are respectively threaded to both ends of the adjusting sleeve (830). The adjusting sleeve (830) is used to manually rotate to adjust the included angle between the first plate (110) and the second plate (120).

8. A method for protecting a negative bending moment tensioning hole, characterized in that: It is carried out based on the negative bending moment tensioning hole protection device according to any one of claims 1-7, and specifically includes the following steps: Step S1: First, fix the first plate (110) at the negative bending moment tensioning hole. Step S2: Rotate the second plate (120) relative to the first plate (110) to form a perpendicular shape; Step S3: Rotate the third plate (130) relative to the second plate (120) to make it perpendicular; Step S4: Rotate the fourth plate (140) relative to the third plate (130), and fasten the first plate (110) and the fourth plate (140) together through the connecting rod (710); Step S5: The first plate (110), the second plate (120), the third plate (130) and the fourth plate (140) together form a protective ring to protect the negative bending moment tensioning hole.

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