Fixing frame for detecting anti-sliding coefficient of high-strength bolt

Abstract

The utility model provides a fixing frame for anti-slip coefficient detection of a high-strength bolt, which relates to the technical field of anti-slip coefficient detection and comprises a fixing table, two first U-shaped frames are symmetrically arranged on the upper surface of the fixing table front and back, and two second U-shaped frames are symmetrically arranged at the upper ends of the first U-shaped frames left and right. The lower surfaces of the front and rear ends of the second U-shaped frame are connected with the upper ends of the first U-shaped frames on the front and rear sides, a fixing assembly is arranged at the upper end of the second U-shaped frame, and a mounting groove is formed in the upper surface of the lower end of the second U-shaped frame. According to the utility model, the mounting grooves are formed in the upper surface of the lower end of the second U-shaped frame, when the anti-slip coefficient of the high-strength bolt is detected, the two ends of a test piece are respectively placed in the two mounting grooves, then the test piece is pressed in the mounting grooves through the fixing assemblies, and the front side and the rear side of the test piece are limited through the mounting grooves; the test piece is prevented from shifting due to front-back sliding on the second U-shaped frame, and the mounting stability of the test piece is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of anti-slip coefficient detection, in particular to a fixing frame for detecting the anti-slip coefficient of a high-strength bolt. Background Art

[0002] The anti-slip test mainly evaluates the ratio of the external force that causes the friction surface of the connection to slide in the high-strength bolt connection to the sum of the pre-tension of the high-strength bolts perpendicular to the friction surface, that is, the anti-slip coefficient. The determination of this coefficient is crucial for the design of high-strength bolt connections in steel structures. It is a key parameter for judging whether the connection meets the design requirements and ensuring the safety of steel structures.

[0003] For example, the Chinese patent with the authorization announcement number CN220650420U discloses a torque device for detecting the anti-slip coefficient of high-strength bolts, which belongs to the technical field of anti-slip coefficient detection. The torque device for detecting the anti-slip coefficient of high-strength bolts includes a fixing component and a connecting component, the fixing component includes a fixing frame and a clamping member, the clamping member is arranged on the top of the fixing frame, the connecting component includes an intermediate plate, a side plate, a high-strength bolt, a pressure sensor and a nut, the intermediate plate is overlapped on the top of the fixing frame, the side plate is provided with two and arranged on both sides of the intermediate plate, the high-strength bolt passes through the intermediate plate and the side plate, by setting the fixing frame and the clamping member, the preliminarily assembled connecting component can be clamped and fixed, by setting the intermediate plate, the side plate, the high-strength bolt, the pressure sensor and the nut, a component for detecting the anti-slip coefficient of the high-strength bolt can be formed, and the nut can be tightened on the high-strength bolt by using a hand-cranked pneumatic gun, the structure is simple and practical, and the cost is low.

[0004] However, the above-mentioned connecting component is placed horizontally on the fixed frame. When the connecting component is pressed, the front and rear sides of the connecting component are not fixed. Therefore, there is a problem of poor stability in the process of pressing the connecting component. The connecting component is easy to slide along the upper surface of the fixed frame, causing the connecting component to be offset and unable to be accurately pressed. Utility Model Content

[0005] The utility model provides a fixing frame for detecting the anti-slip coefficient of a high-strength bolt, which is used to solve the technical problems raised in the above-mentioned background technology.

[0006] In order to solve the above technical problems, the utility model discloses a fixing frame for detecting the anti-slip coefficient of high-strength bolts, comprising: a fixing platform, two first U-shaped frames are symmetrically arranged on the upper surface of the fixing platform, two second U-shaped frames are symmetrically arranged on the upper end of the first U-shaped frame, the lower surfaces of the front and rear ends of the second U-shaped frame are respectively connected to the upper ends of the first U-shaped frames on the front and rear sides, a fixing component is arranged on the upper end of the second U-shaped frame, and a mounting groove is arranged on the upper surface of the lower end of the second U-shaped frame.

[0007] Preferably, the fixing assembly includes a threaded hole passing through the upper end of the second U-shaped frame, a screw rod is threadedly connected to the threaded hole, the lower end of the screw rod extends above the mounting groove, and the upper end of the screw rod extends above the second U-shaped frame and is provided with a nut.

[0008] Preferably, an adjusting rod is arranged above the second U-shaped frame, and one end of the adjusting rod is fixedly connected to the outer wall of the screw rod.

[0009] Preferably, a pressing plate is provided at the lower end of the screw, and the cross-sectional area of ​​the pressing plate is larger than the cross-sectional area of ​​the screw.

[0010] Preferably, a first opening is provided on the upper side of the first U-shaped frame.

[0011] Preferably, the second U-shaped frame is provided with a second opening toward the front side.

[0012] Preferably, a reinforcing plate is arranged between the first U-shaped frame and the fixing platform, one side of the reinforcing plate is connected to the upper surface of the fixing platform, and the other side of the reinforcing plate is connected to the side wall of the first U-shaped frame.

[0013] Preferably, four supporting legs are arranged at the bottom of the fixed platform, and a cross bar is arranged between two adjacent supporting legs.

[0014] Preferably, a through hole is vertically arranged in the installation groove, a sliding column is slidably arranged in the through hole, the lower end of the sliding column extends to the bottom of the second U-shaped frame and a horizontal plate is arranged, a buffer spring is sleeved on the outside of the sliding column, one end of the buffer spring is connected to the upper surface of the horizontal plate, and the other end of the buffer spring is connected to the lower surface of the second U-shaped frame, the upper end of the sliding column extends into the installation groove and a support plate is arranged, and an anti-slip pad is arranged on the upper surface of the support plate.

[0015] Preferably, anti-skid holes are symmetrically arranged on the front and rear sides of the mounting groove, a rotating plate is arranged in the anti-skid hole, a rotating shaft is arranged in the center of the rotating plate, the left and right ends of the rotating shaft are rotatably connected to the left and right inner walls of the anti-skid hole respectively, a protrusion is arranged on the side where the upper ends of the two rotating plates are close to each other, a connecting spring is arranged on the side of the rotating plate away from the protrusion, one end of the connecting spring is connected to the side wall of the upper end of the rotating plate, and the other end of the connecting spring is connected to the inner wall of the anti-skid hole, a contact block is arranged on the side where the lower ends of the two rotating plates are close to each other, and the upper surface of the two contact blocks on the side where they are close to each other is arranged as an inclined surface.

[0016] The technical solution of the utility model has the following advantages: the utility model provides a fixing frame for detecting the anti-slip coefficient of high-strength bolts, which relates to the technical field of anti-slip coefficient detection, and includes a fixing table, two first U-shaped frames are symmetrically arranged on the upper surface of the fixing table, two second U-shaped frames are symmetrically arranged on the upper end of the first U-shaped frame, the lower surfaces of the front and rear ends of the second U-shaped frame are respectively connected to the upper ends of the first U-shaped frames on the front and rear sides, a fixing component is arranged on the upper end of the second U-shaped frame, and a mounting groove is arranged on the upper surface of the lower end of the second U-shaped frame. In the utility model, a mounting groove is provided on the upper surface of the lower end of the second U-shaped frame, and when the anti-slip coefficient of the high-strength bolt is detected, the two ends of the specimen are first placed in the two mounting grooves respectively, and then the specimen is pressed in the mounting groove by the fixing component, and the front and rear sides of the specimen are limited by the mounting groove to avoid the specimen from being offset due to sliding forward and backward on the second U-shaped frame, thereby improving the stability of the specimen installation.

[0017] Other features and advantages of the utility model will be described in the following description, and partly become apparent from the description, or understood by implementing the utility model. The purpose and other advantages of the utility model can be realized and obtained by the devices specifically pointed out in the written description and the drawings of the description.

[0018] The technical solution of the utility model is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0020] Figure 1 This is a schematic diagram of the overall structure of a fixing frame for detecting the anti-slip coefficient of a high-strength bolt according to the utility model;

[0021] Figure 2 This is a front view of a fixing frame for detecting the anti-slip coefficient of high-strength bolts of the utility model;

[0022] Figure 3 It is a side view of a fixing frame for detecting the anti-slip coefficient of a high-strength bolt of the utility model;

[0023] Figure 4 For this utility model Figure 3 A magnified view of the structure in the middle.

[0024] In the figure: 1. fixed platform; 2. first U-shaped frame; 3. second U-shaped frame; 4. mounting groove; 5. screw; 6. nut; 7. adjusting rod; 8. pressure plate; 9. first opening; 10. second opening; 11. reinforcing plate; 12. supporting leg; 13. cross bar; 14. sliding column; 15. cross plate; 16. buffer spring; 17. supporting plate; 18. anti-skid pad; 19. anti-skid hole; 20. rotating plate; 21. rotating shaft; 22. bump; 23. connecting spring; 24. contact block; 25. test piece. DETAILED DESCRIPTION

[0025] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0026] In addition, in the present utility model, the descriptions of "first", "second", etc. are only used for descriptive purposes, and do not specifically refer to the order or sequence, nor are they used to limit the present utility model. They are only used to distinguish components or operations described with the same technical terms, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions and technical features between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0027] Embodiment 1:

[0028] The utility model embodiment provides a fixing frame for detecting the anti-slip coefficient of high-strength bolts, such as Figure 1-Figure 4 As shown, it includes: a fixed platform 1, two first U-shaped frames 2 are symmetrically arranged on the upper surface of the fixed platform 1, two second U-shaped frames 3 are symmetrically arranged on the upper end of the first U-shaped frame 2, the lower surfaces of the front and rear ends of the second U-shaped frame 3 are respectively connected to the upper ends of the first U-shaped frames 2 on the front and rear sides, a fixing component is arranged on the upper end of the second U-shaped frame 3, and a mounting groove 4 is arranged on the upper surface of the lower end of the second U-shaped frame 3.

[0029] The working principle and beneficial effects of the above technical solution are as follows: the fixed platform 1 is used to support the first U-shaped frame 2, the two first U-shaped frames 2 are fixedly arranged on the upper surface of the fixed platform 1, two second U-shaped frames 3 are arranged on the upper end of the first U-shaped frame 2, the second U-shaped frame 3 is perpendicular to the first U-shaped frame 2, and the front and rear ends of the second U-shaped frame 3 are respectively fixedly connected to the upper ends of the first U-shaped frames 2 on the front and rear sides, and a mounting groove 4 is provided on the upper surface of the lower end of the second U-shaped frame 3, and the mounting groove 4 is used to place the test piece 25. When in use, the two ends of the test piece 25 are first placed on the two ends of the test piece 25 respectively. The test piece 25 is then pressed into the installation groove 4 by the fixing assembly, and the anti-slip coefficient test of the high-strength bolt can be carried out. The front and rear sides of the test piece 25 are limited by the installation groove 4 to prevent the test piece 25 from deviating due to front and rear sliding on the second U-shaped frame 3, thereby improving the installation stability of the test piece 25. The two ends of the test piece 25 are respectively placed in the installation groove 4. During the process of fixing the test piece 25 by the fixing assembly, the fixing assembly can be aligned with the test piece 25, thereby accurately pressing the test piece 25, and further improving the stability of the test piece 25.

[0030] Example 2

[0031] On the basis of the above-mentioned embodiment 1, Figure 1 As shown, the fixing assembly includes a threaded hole passing through the upper end of the second U-shaped frame 3, a screw rod 5 is threadedly connected in the threaded hole, the lower end of the screw rod 5 extends above the mounting groove 4, and the upper end of the screw rod 5 extends above the second U-shaped frame 3 and is provided with a nut 6.

[0032] The working principle and beneficial effects of the above technical solution are as follows: after placing the specimen 25 in the mounting groove 4, the nut 6 is rotated to drive the screw 5 to rotate, and the screw 5 moves toward the specimen 25 through thread transmission until the specimen 25 is pressed, thereby fixing the specimen 25 on the second U-shaped frame 3.

[0033] Example 3

[0034] On the basis of Example 2, Figure 3 As shown, an adjusting rod 7 is arranged above the second U-shaped frame 3 , and one end of the adjusting rod 7 is fixedly connected to the outer wall of the screw rod 5 .

[0035] The working principle and beneficial effects of the above technical solution are as follows: the length of the adjusting rod 7 is greater than the radius of the nut 6. When the test piece 25 is pressed, the screw 5 is first rotated by the adjusting rod 7, which is more labor-saving, can speed up the pressing speed, and improve the detection efficiency.

[0036] Example 4

[0037] On the basis of any one of Examples 1-3, Figure 3 As shown, a pressing plate 8 is arranged at the lower end of the screw rod 5 , and the cross-sectional area of ​​the pressing plate 8 is larger than the cross-sectional area of ​​the screw rod 5 .

[0038] The working principle and beneficial effects of the above technical solution are as follows: the pressure plate 8 can be made of anti-slip material, the pressure plate 8 contacts the upper surface of the specimen 25 and presses the specimen 25 into the mounting groove 4. By setting the pressure plate 8, the contact area can be increased, the friction force can be increased, and the specimen 25 can be prevented from sliding left and right in the mounting groove 4, thereby further improving the stability of the specimen 25 and ensuring the accuracy of the test results.

[0039] Example 5

[0040] On the basis of any one of Examples 1-4, Figure 1 As shown, the first U-shaped frame 2 is provided with a first opening 9 on the upper side.

[0041] The working principle and beneficial effects of the above technical solution are as follows: the first opening 9 of the first U-shaped frame 2 is arranged upward. By setting the first opening 9, the overall weight of the fixed frame can be reduced, which is convenient for carrying. Moreover, by setting the first opening 9 upward, the operating space of the staff can be increased, which is convenient for the staff to work. At the same time, it can reduce the bumps during the operation of the staff, thereby improving the safety of the operation.

[0042] Example 6

[0043] On the basis of any one of Examples 1-5, Figure 1 As shown, the second U-shaped frame 3 is provided with a second opening 10 toward the front side.

[0044] The working principle and beneficial effects of the above technical solution are as follows: the second opening 10 of the second U-shaped frame 3 is arranged forward, and the test piece 25 can be placed horizontally into the second U-shaped frame 3 through the second opening 10, so as to facilitate the installation and removal of the test piece 25.

[0045] Example 7

[0046] On the basis of any one of Examples 1-6, Figure 3 As shown, a reinforcing plate 11 is arranged between the first U-shaped frame 2 and the fixing platform 1 , one side of the reinforcing plate 11 is connected to the upper surface of the fixing platform 1 , and the other side of the reinforcing plate 11 is connected to the side wall of the first U-shaped frame 2 .

[0047] The working principle and beneficial effects of the above technical solution are as follows: the reinforcing plate 11 is arranged between the first U-shaped frame 2 and the fixing platform 1, which can enhance the stability of the reinforcing plate 11 and extend the service life of the fixing frame.

[0048] Example 8

[0049] On the basis of any one of Examples 1-7, Figure 1 As shown, four supporting legs 12 are arranged at the bottom of the fixing platform 1 , and a cross bar 13 is arranged between two adjacent supporting legs 12 .

[0050] The working principle and beneficial effects of the above technical solution are as follows: four support legs 12 are arranged at the bottom of the fixed platform 1, and the support legs 12 can provide support for the fixed platform 1, while increasing the overall height of the fixed frame, eliminating the need for workers to bend over to work, making inspection more convenient, and the cross bars 13 between the support legs 12 can enhance the stability of the support legs 12 and prevent the support legs 12 from shaking at the bottom of the fixed platform 1.

[0051] Example 9

[0052] On the basis of any one of Examples 1-8, Figure 3 , Figure 4 As shown, a through hole is vertically arranged in the mounting groove 4, a sliding column 14 is slidably arranged in the through hole, the lower end of the sliding column 14 extends to the bottom of the second U-shaped frame 3 and a cross plate 15 is arranged, a buffer spring 16 is sleeved on the outside of the sliding column 14, one end of the buffer spring 16 is connected to the upper surface of the cross plate 15, and the other end of the buffer spring 16 is connected to the lower surface of the second U-shaped frame 3, the upper end of the sliding column 14 extends into the mounting groove 4 and a support plate 17 is arranged, and an anti-slip pad 18 is arranged on the upper surface of the support plate 17.

[0053] The working principle and beneficial effects of the above technical solution are as follows: when the test piece 25 is placed in the installation groove 4, the lower surface of the test piece 25 first contacts the anti-skid pad 18. The anti-skid pad 18 is made of anti-skid material, which can increase the friction force to prevent the test piece 25 from sliding left and right in the installation groove 4. After the test piece 25 contacts the anti-skid pad 18, it drives the anti-skid pad 18 to move downward, and the anti-skid pad 18 drives the support plate 17 to slide downward synchronously. The support plate 17 drives the sliding column 14 to slide downward in the through hole, and drives the cross plate 15 to move downward, and the buffer spring 16 is gradually stretched. The elastic force of the buffer spring 16 can slow down the falling speed of the test piece 25, so as to prevent the test piece 25 from falling too fast and damaging the installation groove 4, thereby extending the service life of the entire fixing frame.

[0054] Example 10

[0055] On the basis of any one of Examples 1-9, Figure 3 , Figure 4 As shown, anti-skid holes 19 are symmetrically arranged on the front and rear sides of the mounting groove 4, a rotating plate 20 is arranged in the anti-skid hole 19, a rotating shaft 21 is arranged at the center of the rotating plate 20, and the left and right ends of the rotating shaft 21 are rotatably connected to the inner walls of the left and right sides of the anti-skid hole 19 respectively, a protrusion 22 is arranged on the side where the upper ends of the two rotating plates 20 are close to each other, and a connecting spring 23 is arranged on the side where the rotating plate 20 is away from the protrusion 22, one end of the connecting spring 23 is connected to the side wall of the upper end of the rotating plate 20, and the other end of the connecting spring 23 is connected to the inner wall of the anti-skid hole 19, a contact block 24 is arranged on the side where the lower ends of the two rotating plates 20 are close to each other, and the upper surface of the side where the two contact blocks 24 are close to each other is arranged as an inclined surface.

[0056] The working principle and beneficial effects of the above technical solution are as follows: in the process of the specimen 25 sliding down into the installation groove 4, the specimen 25 drives the cross plate 15 to slide downward, and the lower surface of the cross plate 15 contacts the inclined surface of the contact block 24 and pushes the contact block 24 to move into the anti-slip hole 19, and the contact block 24 drives the rotating plate 20 to rotate with the rotating shaft 21 as the center, and the protrusion 22 at the upper end of the rotating plate 20 moves toward the outside of the anti-slip hole 19 and gradually presses the outer wall of the specimen 25, and the connecting spring 23 is stretched. The protrusion 22 is made of elastic anti-slip material. The protrusion 22 squeezes the front and rear side walls of the specimen 25, which can further improve the stability of the specimen 25 in the installation groove 4, not only can it prevent the specimen 25 from sliding back and forth, but also can prevent the specimen 25 from sliding left and right in the installation groove 4, so that the fixing component accurately presses the specimen 25, improves the reliability of the installation of the specimen 25, and makes the detection result more accurate.

[0057] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0058] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0059] Although the implementation scheme of the utility model has been disclosed as above, it is not limited to the applications listed in the specification and implementation modes. It can be fully applied to various fields suitable for the utility model. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the utility model is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A fixing frame for detecting the anti-slip coefficient of high-strength bolts, characterized in that: include: A fixed platform (1), wherein two first U-shaped frames (2) are symmetrically arranged on the upper surface of the fixed platform (1), two second U-shaped frames (3) are symmetrically arranged on the upper ends of the first U-shaped frames (2), the lower surfaces of the front and rear ends of the second U-shaped frames (3) are respectively connected to the upper ends of the first U-shaped frames (2) on the front and rear sides, a fixing component is arranged on the upper end of the second U-shaped frames (3), and a mounting groove (4) is arranged on the upper surface of the lower end of the second U-shaped frames (3).

2. The fixing frame for detecting the anti-slip coefficient of high-strength bolts according to claim 1 is characterized in that: The fixing assembly comprises a threaded hole penetrating the upper end of the second U-shaped frame (3), a screw rod (5) being threadedly connected in the threaded hole, the lower end of the screw rod (5) extending to above the mounting groove (4), and the upper end of the screw rod (5) extending to above the second U-shaped frame (3) and provided with a nut (6).

3. The fixing frame for detecting the anti-slip coefficient of high-strength bolts according to claim 2 is characterized in that: An adjusting rod (7) is arranged above the second U-shaped frame (3), and one end of the adjusting rod (7) is fixedly connected to the outer wall of the screw rod (5).

4. The fixing frame for detecting the anti-slip coefficient of high-strength bolts according to claim 2, characterized in that: A pressing plate (8) is arranged at the lower end of the screw rod (5), and the cross-sectional area of ​​the pressing plate (8) is larger than the cross-sectional area of ​​the screw rod (5).

5. The fixing frame for detecting the anti-slip coefficient of high-strength bolts according to claim 1, characterized in that: The first U-shaped frame (2) is provided with a first opening (9) on the upper side.

6. The fixing frame for detecting the anti-slip coefficient of high-strength bolts according to claim 1, characterized in that: The second U-shaped frame (3) is provided with a second opening (10) on the front side.

7. The fixing frame for detecting the anti-slip coefficient of high-strength bolts according to claim 1, characterized in that: A reinforcing plate (11) is arranged between the first U-shaped frame (2) and the fixing platform (1); one side of the reinforcing plate (11) is connected to the upper surface of the fixing platform (1), and the other side of the reinforcing plate (11) is connected to the side wall of the first U-shaped frame (2).

8. The fixing frame for detecting the anti-slip coefficient of high-strength bolts according to claim 1, characterized in that: Four supporting legs (12) are arranged at the bottom of the fixed platform (1), and a crossbar (13) is arranged between two adjacent supporting legs (12).

9. The fixing frame for detecting the anti-slip coefficient of high-strength bolts according to claim 1, characterized in that: A through hole is vertically arranged in the installation groove (4), a sliding column (14) is slidably arranged in the through hole, the lower end of the sliding column (14) extends to the bottom of the second U-shaped frame (3) and a horizontal plate (15) is arranged, a buffer spring (16) is sleeved on the outside of the sliding column (14), one end of the buffer spring (16) is connected to the upper surface of the horizontal plate (15), and the other end of the buffer spring (16) is connected to the lower surface of the second U-shaped frame (3), the upper end of the sliding column (14) extends into the installation groove (4) and a support plate (17) is arranged, and an anti-slip pad (18) is arranged on the upper surface of the support plate (17).

10. The fixing frame for detecting the anti-slip coefficient of high-strength bolts according to claim 1, characterized in that: Anti-skid holes (19) are symmetrically arranged on the front and rear sides of the mounting groove (4), a rotating plate (20) is arranged in the anti-skid hole (19), a rotating shaft (21) is arranged at the center of the rotating plate (20), and the left and right ends of the rotating shaft (21) are respectively rotatably connected with the inner walls of the left and right sides of the anti-skid hole (19), a protrusion (22) is arranged on the upper ends of the two rotating plates (20) close to each other, and a connecting spring (23) is arranged on the side of the rotating plate (20) away from the protrusion (22), one end of the connecting spring (23) is connected to the side wall of the upper end of the rotating plate (20), and the other end of the connecting spring (23) is connected to the inner wall of the anti-skid hole (19), a contact block (24) is arranged on the lower ends of the two rotating plates (20) close to each other, and the upper surfaces of the two contact blocks (24) close to each other are arranged as inclined surfaces.

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