Testing device for detecting friction coefficient of municipal road pavement

Abstract

The invention discloses a test device for detecting a municipal road surface friction coefficient, and relates to the technical field of road surface friction coefficient detection. Comprising a frame, a load frame, a traction fixing piece, a tension meter, a traction rope and a towed object, the traction fixing piece is installed at one end close to the advancing direction of the frame, the load frame is installed at one end far away from the traction fixing piece, the towed object is arranged below the load frame and located at the bottom of the frame, and a tire simulation piece is arranged at the bottom of the towed object. The towed object can be separated from the frame and placed on the road surface. According to the invention, through the modes of weight increment of the standard heavy object, tire simulation by sliding of the tire simulation piece and the like, the tension meter is combined to measure tension, and reliable data is calculated by using a formula, so that the anti-skid performance of the road surface can be effectively evaluated, a scientific basis is provided for road material selection and laying process optimization and maintenance, and the service life of the road is prolonged; therefore, the traction rope can be adaptively adjusted to a horizontal state when detecting a slope road, and data can be accurately collected.

Description

Technical Field

[0001] The present invention relates to the technical field of road surface friction coefficient detection, and particularly to a test device for detecting the friction coefficient of municipal road surfaces. Background Technique

[0002] The friction coefficient is directly related to the braking distance and stability of vehicles. Sufficient friction force is required to enable the vehicle to stop in time during braking and avoid accidents such as rear-end collisions. Especially on rainy, snowy, or slippery road surfaces, the reduction of the friction coefficient will multiply the braking distance and threaten driving safety. By detecting the friction coefficient, the anti-slip performance of the road surface can be evaluated, providing a basis for road material selection and paving process optimization. It can also monitor the wear and aging of the road surface, arrange maintenance and repair in a timely manner, and extend the service life of the road.

[0003] The towing method is a relatively simple way to detect the road surface friction coefficient. The vehicle pulls the friction block to travel on the road surface, and the friction coefficient is calculated based on the mass of the friction block and the pulling force for moving the friction block. In the actual operation process, generally in the form of the vehicle pulling the friction block to move on the road surface, the friction coefficient is calculated based on the mass of the friction block and the pulling force for moving the friction block. However, the stability is poor, and the adjustment is very troublesome when detecting inclined road surfaces. Therefore, in view of this situation, the present invention proposes a new solution to improve the above problems. Summary of the Invention

[0004] The purpose of the present invention is to provide a test device for detecting the friction coefficient of municipal road surfaces to solve the problems raised in the above background technique.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A test device for detecting the friction coefficient of municipal road surfaces, comprising: A vehicle frame, a load frame, a traction fixing member, a tensiometer, a traction rope, and a towing object; The traction fixing member is installed at one end close to the advancing direction of the vehicle frame, the load frame is installed at the end away from the traction fixing member, and a towing object is provided below the load frame and at the bottom of the vehicle frame; The bottom of the towing object is a tire simulation part. The towing object can be separated from the vehicle frame and placed on the road surface. Standard weights are placed in the load frame. When detecting the friction coefficient of the road surface, the standard weights are placed on the towing object to increase the load of the towing object; The traction rope is connected between the traction fixing member and the towing object, and the tensiometer is used to detect the pulling force during the process of pulling the towing object; The traction rope is always horizontally arranged with the road plane under the action of the traction fixing member.

[0006] Regarding this solution, further, the vehicle frame includes a first frame plate and a second frame plate. There is a gap between the first frame plate and the second frame plate, and the first frame plate and the second frame plate are connected by a number of fixing rods. Wheels are installed on both sides of the vehicle frame.

[0007] Regarding this solution, further, the traction fixing member includes a slide rail frame. The slide rail frame is fixed to the bottom of the first frame plate facing the forward route. The slide rail frame is rod-shaped and has chutes on both sides. Sliders are slidably connected to the chutes, and a U-shaped frame is fixedly connected between the two sliders. A rotating shaft block is rotatably connected between the inner walls on both sides of the U-shaped frame.

[0008] Regarding this solution, further, one end of the tensiometer is connected to one end of the traction rope, and the other end of the tensiometer is installed on the rotating shaft block.

[0009] Regarding this solution, further, the towed object includes a sliding bottom plate. The tire simulation member is fixed to the towed object. The tire is simulated by the tire simulation member sliding on the road surface. A limiting frame is fixed to the top of the sliding bottom plate and is a rectangular frame. The length and width of the inner wall of the limiting frame are the same as those of the inner wall of the load frame. A number of standard weights are provided and are all stacked and installed in the load frame.

[0010] Regarding this solution, further, the standard weight is an iron shell with an inverted conical shape and each standard weight has the same mass. A retaining member is provided on the vehicle frame. The fixing member fixes the lowermost standard weight in the load frame.

[0011] Regarding this solution, further, notch openings are provided on both sides of the load frame. The retaining member includes a fixing plate. The fixing plate is fixed to the top of the second frame plate on both sides of the load frame. Two limiting rods are slidably installed on the fixing plate. One end of the limiting rod facing the load frame is fixed with an inclined surface clamping block. The top surface of the inclined surface clamping block is an inclined surface, and a spring is provided between the inclined surface clamping block and the fixing plate. The spring is sleeved on the surface of the limiting rod. The inclined surface clamping block is clamped at the edge of the lowermost standard weight through the elasticity of the spring. The limiting frame is fixed to the sliding bottom plate by a number of screws provided at the bottom.

[0012] Regarding this solution, further, a screw joint is fixed on the surface of the rotating shaft block. One end of the tensiometer is screwed to the screw joint. A positioning frame is fixed to one side of the sliding bottom plate close to the traction fixing member. A screw joint block is provided at the positioning frame. One end of the screw joint block passes through the middle of the positioning frame. One end of the traction rope close to the towed object is fixed with a screw cap. The screw cap is screwed and fixed to the screw joint.

[0013] Regarding this solution, further, the positioning frame is a rectangular frame body and a center of gravity mark is provided on the side facing the traction fixing member. The center of gravity mark is marked according to the center of gravity of different numbers of standard weights on the towed object.

[0014] Furthermore, with regard to this solution, side plates are fixed to both sides of the sliding bottom plate. The top of the side plate is flat. Threaded holes are provided on the second mounting plate, and threaded holes corresponding to the threaded holes of the second mounting plate are also provided on the flat surface of the top of the side plate. A tightening bolt is screwed at the threaded hole to connect the towed object to the vehicle frame through the tightening bolt; An angle measuring instrument is provided at the center of the second mounting plate. A support rod is fixed on the surface of the rotating shaft block. A level is provided on the support rod, and the support rod is coaxially arranged with the screw joint.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: The test device for detecting the friction coefficient of the municipal road surface uses methods such as increasing the weight of the standard weight and simulating the sliding of the tire with the tire simulation part, combines a tensiometer to measure the tension, and calculates reliable data using a formula. It can effectively evaluate the anti-skid performance of the road surface, provide a scientific basis for road material selection, laying process optimization and maintenance, extend the service life of the road. At the same time, the structural design of its traction fixing part enables the traction rope to be adaptively adjusted to a state parallel to the road surface when detecting an inclined road, accurately collect data, solves the problem of difficult adjustment in the detection of inclined road surfaces by the traditional towing method, and improves the accuracy and adaptability of the detection.

[0016] At the same time, the device uses the towing method for detection. The equipment is simple, only basic components such as a vehicle frame, a load box, a traction fixing part, a tensiometer, a traction rope and a towed object are required. The structure is compact, easy to operate and carry, without complex and expensive supporting equipment, reducing the detection cost. Moreover, the vehicle frame has good stability and is convenient to move with the wheels, and can meet the detection requirements of different road sections. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram of the overall structure of the present invention; Figure 2 is a schematic diagram of the structure from the bottom view of the present invention; Figure 3 is a schematic diagram of the overall sectional structure of the present invention; Figure 4 is a schematic diagram of the position state of the traction fixing part and the towed object of the present invention; Figure 5 is a schematic diagram of the state of the traction fixing part and the towed object from another perspective of the present invention.

[0018] In the figure: 1. First shelf board; 2. Second shelf board; 3. Fixed rod; 4. Load frame; 5. Wheel; 6. Angle measuring instrument; 7. Towing fixture; 701. Slide rail frame; 702. C-shaped frame; 703. Slide block; 704. Rotating shaft block; 705. Support rod; 706. Level gauge; 707. Screw rod; 708. Screw joint; 8. Tensile meter; 9. Towing rope; 901. Screw joint nut; 10. Towed object; 1001. Sliding bottom plate; 1002. Side plate; 1003. Tightening bolt; 1004. Limit frame; 1005. Screw; 1006. Positioning frame; 1007. Center of gravity mark; 1008. Screw joint block; 1009. Tire simulation part; 11. Standard weight; 12. Retaining part; 121. Fixed plate; 122. Inclined surface clamping block; 123. Spring; 124. Limit rod; 125. Limit plate; 13. Auxiliary power device. Detailed implementation manners

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0020] As Figure 1 and Figure 2 and Figure 3 shown, the present invention provides a technical solution: a test device for detecting the friction coefficient of the municipal road surface, including a vehicle frame, a load frame 4, a towing fixture 7, a tensile meter 8, a towing rope 9, and a towed object 10.

[0021] The vehicle frame includes a first shelf board 1 and a second shelf board 2. A gap is provided between the first shelf board 1 and the second shelf board 2, and the first shelf board 1 and the second shelf board 2 are connected by a plurality of fixed rods 3. The first shelf board 1, the second shelf board 2, and the fixed rods 3 form a vehicle frame with better stability. Wheels 5 are installed on both sides of the vehicle frame to meet the necessary conditions for the movement of the vehicle frame and the detection of the road surface friction coefficient.

[0022] The test device for the friction coefficient mainly detects the road surface coefficient through the towing method. The towing method is more convenient than other methods available for detecting the road surface coefficient and requires fewer necessary equipment. The traction fixing part 7 is installed at one end close to the advancing direction of the vehicle frame and at the bottom of the vehicle frame. The load frame 4 is installed at the end of the vehicle frame far from the traction fixing part 7. A towing object 10 is arranged below the load frame 4 and at the bottom of the vehicle frame. The bottom of the towing object 10 is a tire simulation part 1009. The towing object 10 can be separated from the vehicle frame and placed on the road surface. Standard weights 11 are placed in the load frame 4. When detecting the road surface friction coefficient, the standard weights 11 are placed on the towing object 10 to increase the load of the towing object 10. A traction rope 9 is connected between the traction fixing part 7 and the towing object 10, and a tensiometer 8 is used to detect the pulling force during the process of pulling the towing object 10. It should be noted that the traction rope 9 is always set horizontally with the road plane. After collecting data, or the road surface friction coefficient is calculated by two groups of formulas. Among them, F is the towing force, that is, the pulling force, m is the mass of the towing object 10, θ is the inclination angle of the road, μ is the calculated friction coefficient, and when detecting an inclined road surface, the towing direction is defaulted to the uphill direction.

[0023] As Figure 3 and Figure 4 shown, regarding the above-mentioned embodiments, it should be noted that the traction fixing part 7 includes a slide rail frame 701. The slide rail frame 701 is fixed to the bottom of the first frame plate 1 along the advancing route. The slide rail frame 701 is in the shape of a rod and has chutes on both sides. Sliders 703 are slidably connected to the chutes, and a U-shaped frame 702 is fixedly connected between the two sliders 703. A rotating shaft block 704 is rotatably connected between the inner walls on both sides of the U-shaped frame 702. That is to say, the rotating shaft block 704 can rotate around its own axis in the U-shaped frame 702; It should be noted that one end of the tensiometer 8 is connected to one end of the traction rope 9, and the other end of the tensiometer 8 is installed on the rotating shaft block 704, while the other end of the traction rope 9 is connected to the towing object 10. That is to say, when the road surface friction coefficient detection device detects an inclined road surface, the traction rope 9 can be adjusted to a state horizontal with the road surface, and the data required for the road surface friction coefficient can be collected relatively accurately.

[0024] As Figure 3 and Figure 4As shown, regarding the above embodiments, it should also be noted that the drag object 10 includes a sliding bottom plate 1001. The tire simulation member 1009 is fixed to the drag object 10 in a manner of being bolted with a square plate. That is to say, the tire simulation member 1009 can be replaced so as to be tested with tires of different materials. The tire simulation member 1009 slides on the road surface to simulate a tire. A limit frame 1004 is fixed on the top of the sliding bottom plate 1001. The limit frame 1004 is a rectangular frame, and the length and width of the inner wall of the limit frame 1004 are the same as those of the inner wall of the load frame 4. Among them, a number of standard weights 11 are provided and are all stacked and installed in the load frame 4.

[0025] Theoretically, the road surface friction coefficient is a material property. Therefore, in fact, the weight of an object will not affect the detection of the road surface friction coefficient. Therefore, by repeatedly performing the friction coefficient detection with standard objects of different weights and repeatedly verifying, the experimental results can be made accurate.

[0026] In this embodiment, the standard weight 11 used is an iron shell with an inverted conical shape and each standard weight 11 has the same mass. In the load frame 4, the four sides of the standard weight 11 abut against the four inner walls of the load frame 4. A retaining member 12 is provided on the vehicle frame. The retaining member 12 limits the position of the lowermost standard weight 11 in the load frame 4 to limit the positions of multiple standard weights 11. The retaining member 12 can lower one standard weight 11 each time through an external force operation, and the operation is relatively simple.

[0027] As Figure 4 and Figure 5 As shown, to implement the above embodiments, it should be noted that notches are provided on both sides of the load frame 4. The retaining member 12 includes a fixing plate 121. The fixing plate 121 is fixed to the top of the second frame plate 2 on both sides of the load frame 4. Two limiting rods 124 are slidably installed on the fixing plate 121. A limiting plate 125 is fixed to the end of the limiting rod 124 away from the load frame 4. An inclined surface clamping block 122 is fixed to the end of the limiting rod 124 facing the load frame 4. The top surface of the inclined surface clamping block 122 is an inclined surface, and a spring 123 is provided between the inclined surface clamping block 122 and the fixing plate 121. The spring 123 is sleeved on the surface of the limiting rod 124. The inclined surface clamping block 122 is clamped at the edge of the lowermost standard weight 11 through the elasticity of the spring 123. During the actual operation process, by manually pressing on the uppermost standard weight 11, the spring 123 can be compressed and pushed outwards, causing the lowermost standard weight 11 to fall. Since the standard weight 11 is in an inverted conical shape and is convenient for stacking. Among them, the limit frame 1004 is fixed to the sliding bottom plate 1001 through a number of screws 1005 provided at the bottom. That is to say, after the test is completed, the standard weights 11 can be recovered by removing the screws 1005.

[0028] As Figure 4And Figure 5 As shown, to ensure the smooth implementation of this embodiment, it should be noted that a screw joint 708 is fixed on the surface of the rotating shaft block 704. A nut is provided at the tension meter 8, and the nut is installed on the tension meter 8 by welding or other fixing methods. The tension meter 8 is fixed to the rotating shaft block 704 through the cooperation of a screw cap 901 and the screw joint 708. A positioning frame 1006 is fixed on one side of the sliding bottom plate 1001 close to the traction fixing member 7. The positioning frame 1006 is a rectangular frame, and a center of gravity mark 1007 is provided on the side facing the traction fixing member 7. The center of gravity mark 1007 is marked according to the center of gravity of different numbers of standard weights 11 on the towed object 10, so as to ensure that under the state of using different standard weights 11, the traction rope 9 can always be connected to the center of gravity plane of the towed object 10 plus the standard weights 11, so as to avoid the situation of generating torque. A screw joint block 1008 is provided at the positioning frame 1006. One end of the screw joint block 1008 passes through the middle of the positioning frame 1006. A screw cap 901 is fixed to one end of the traction rope 9 close to the towed object 10, and is fixed to the screw joint block 1008 by screwing and clamped on the positioning frame 1006.

[0029] It should be understood that side plates 1002 are fixed on both sides of the sliding bottom plate 1001. The top of the side plates 1002 is a plane. Threaded holes are provided on the second support plate 2, and threaded holes are also provided at the positions corresponding to the threaded holes of the second support plate 2 on the top plane of the side plates 1002. Tightening bolts 1003 are screwed at the threaded holes, and the connection between the towed object 10 and the vehicle frame is realized through the tightening bolts 1003.

[0030] As Figure 2 、 Figure 3 And Figure 4 As shown, it should also be noted that an angle measuring instrument 6 is provided at the center of the second support plate 2. A support rod 705 is fixed on the surface of the rotating shaft block 704, and a spirit level 706 is provided on the support rod 705. The angle measuring instrument 6 is used to detect the angle value of the inclined plane, and the spirit level 706 is used to detect the horizontal state of the traction rope 9. Therefore, the support rod 705 and the screw joint 708 are coaxially arranged. In the specific use process, the road surface friction coefficient detection device is placed on a horizontal road surface. The connection position of the traction rope 9 and the positioning frame 1006 is placed at the marked point of the center of gravity plane and fixed. The height of the rotating shaft block 704 is also adjusted to the same horizontal plane as the marked point by rotating the screw rod 707, and it is judged whether the traction rope 9 is horizontal through the spirit level 706. After preparation is complete, tow the vehicle frame, and the vehicle frame realizes the traction of the towed object 10 during the movement. When detecting the friction coefficient of the inclined road surface, due to the setting of the rotating shaft block 704, the rotating shaft block 704 can adaptively adjust the angle in cooperation with the towed object 10, so that the traction rope 9 remains in a state horizontal to the inclined road surface.

[0031] When the municipal road surface friction coefficient detection device is in use, first place the device on a horizontal road surface. Connect the traction rope 9 to the positioning frame 1006 at the center of gravity plane and fix it. Rotate the screw rod 707 to adjust the height of the rotating shaft block 704 and judge the horizontality of the traction rope 9 through the level 706. During the detection, place the standard weight 11 at the drag object 10 to increase the load. Connect the traction rope 9 and the dynamometer 8 through the traction fixing piece 7. The drag vehicle frame moves. At this time, the tire simulation piece 1009 slides on the road surface to simulate the tire. The dynamometer 8 detects the pulling force for pulling the drag object 10. After collecting the data, calculate the road surface friction coefficient using the formula. When detecting an inclined road, the rotating shaft block 704 cooperates with the drag object 10 to adaptively adjust the angle to ensure that the traction rope 9 is horizontal with the inclined road surface, and accurate data can be collected. It should be noted that both the level 706 and the angle measuring instrument 6 can use electronic products, such as an electronic level and an electronic inclinometer, and cooperate with a computer for data collection and calculation.

[0032] Regarding the above embodiments, it should also be noted that two auxiliary power devices 13 are provided at the bottom of the vehicle frame. The auxiliary power device 13 includes a built-in motor and battery. The auxiliary power device 13 is connected to the wheels 5 and can drive the two wheels 5 on both sides. Therefore, the device can be towed by a vehicle to pull the vehicle frame for the road surface friction coefficient test device, and can be moved through the auxiliary power device 13 of the test device by installing auxiliary wheels at one end in the advancing direction of the vehicle frame.

[0033] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A test device for detecting the friction coefficient of municipal road pavement, characterized in that: Including: A vehicle frame, a load box (4), a towing fixing member (7), a dynamometer (8), a towing rope (9), and a towed object (10); The towing fixing member (7) is installed at one end close to the advancing direction of the vehicle frame, the load box (4) is installed at the end far from the towing fixing member (7), and a towed object (10) is arranged below the load box (4) and at the bottom of the vehicle frame; The bottom of the towed object (10) is a tire simulation member (1009), the towed object (10) can be separated from the vehicle frame and placed on the road surface, standard weights (11) are placed in the load box (4), and when detecting the road surface friction coefficient, the standard weights (11) are placed on the towed object (10) to increase the load of the towed object (10); The towing fixing member (7) and the towed object (10) are connected by a towing rope (9), and the dynamometer (8) is used to detect the pulling force during the process of pulling the towed object (10); The towing rope (9) is always horizontally arranged with the road surface through the action of the towing fixing member (7).

2. A test device for detecting the friction coefficient of municipal road pavement according to claim 1, characterized in that: The vehicle frame includes a first frame plate (1) and a second frame plate (2), a gap is provided between the first frame plate (1) and the second frame plate (2), and the first frame plate (1) and the second frame plate (2) are connected by a plurality of fixing rods (3), and wheels (5) are installed on both sides of the vehicle frame.

3. A test device for detecting the friction coefficient of municipal road pavement according to claim 2, characterized in that: The towing fixing member (7) includes a slide rail frame (701), the slide rail frame (701) is fixed to the bottom of the first frame plate (1) facing the advancing route, the slide rail frame (701) is in the shape of a rod and has sliding grooves on both sides, sliders (703) are slidably connected to the sliding grooves, and a U-shaped frame (702) is fixedly connected between the two sliders (703), a rotating shaft block (704) is rotatably connected between the inner walls on both sides of the U-shaped frame (702), a screw rod (707) is rotatably installed at the top of the U-shaped frame (702), and the screw rod (707) is screwed to the second frame plate (2); An angle measuring instrument (6) is provided at the center of the second frame plate (2), a support rod (705) is fixed on the surface of the rotating shaft block (704), and a level (706) is provided on the support rod (705).

4. A test device for detecting friction coefficient of municipal road surface according to claim 3, characterized in that: One end of the dynamometer (8) is connected to one end of the towing rope (9), and the other end of the dynamometer (8) is installed on the rotating shaft block (704).

5. A test device for detecting friction coefficient of municipal road surface according to claim 1, characterized in that: The towed object (10) includes a sliding bottom plate (1001), the tire simulation member (1009) is fixed on the towed object (10), the tire simulation member (1009) slides on the road surface to simulate a tire, a limiting frame (1004) is fixed on the top of the sliding bottom plate (1001), the limiting frame (1004) is a rectangular frame, and the inner length and width of the limiting frame (1004) are the same as the inner length and width of the load box (4), and a plurality of standard weights (11) are provided and are all stacked and installed in the load box (4).

6. A test device for detecting friction coefficient of municipal road surface according to claim 1, characterized in that: The standard weight (11) is an iron shell in the shape of an inverted cone and each standard weight (11) has the same mass, and a retaining member (12) is provided on the vehicle frame, and the retaining member (12) fixes the lowermost standard weight (11) in the load box (4).

7. A test device for detecting friction coefficient of municipal road surface according to claim 4, characterized in that: The load frame (4) is provided with notches on both sides. The retaining member (12) comprises a fixing plate (121). The fixing plate (121) is fixed to the top of the second frame plate (2) and is located on both sides of the load frame (4). Two limiting rods (124) are slidably mounted on the fixing plate (121). An inclined clamping block (122) is fixed to one end of the limiting rod (124) facing the load frame (4). The top surface of the inclined clamping block (122) is an inclined surface. A spring (123) is provided between the inclined clamping block (122) and the fixing plate (121). The spring (123) is sleeved on the surface of the limiting rod (124). The inclined clamping block (122) is clamped at the edge of the lowest standard weight (11) by the elasticity of the spring (123). The limiting frame (1004) is fixed to the sliding bottom plate (1001) by a plurality of screws (1005) provided at the bottom.

8. A test device for detecting friction coefficient of municipal road surface according to claim 3, characterized in that: A screw joint (708) is fixed to the surface of the rotating shaft block (704), one end of the dynamometer (8) is screwed to the screw joint (708), a positioning frame (1006) is fixed to one side of the sliding base plate (1001) close to the traction fixing member (7), a screw block (1008) is provided at the positioning frame (1006), one end of the screw block (1008) passes through the middle of the positioning frame (1006), a screw cap (901) is fixed to one end of the traction rope (9) close to the towed object (10), and the screw cap (901) is screwed and fixed to the screw joint (708).

9. A test device for detecting friction coefficient of municipal road surface according to claim 8, characterized in that: The positioning frame (1006) is in the form of a rectangular frame and is provided with a center of gravity mark (1007) on one side facing the towing fixing member (7). The center of gravity mark (1007) is marked according to the center of gravity of different numbers of standard weights (11) on the towed object (10).

10. A test device for detecting friction coefficient of municipal road surface according to claim 8, characterized in that: Side plates (1002) are fixed on both sides of the sliding bottom plate (1001). The top of the side plate (1002) is a plane. The top of the side plate (1002) is also provided with a threaded hole, and a tightening bolt (1003) is screwed to the threaded hole.

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