Drop weight deflectometer for road surface detection

Abstract

A drop hammer deflectometer for pavement detection belongs to the technical field of pavement detection equipment and comprises a guide rod, a bearing plate and a heavy hammer, the bearing plate is arranged at the bottom end of the guide rod, the heavy hammer is slidably sleeved on the guide rod, a positioning disc is mounted at the top end of the heavy hammer, and the area of the upper surface of the positioning disc is smaller than that of the lower surface of the positioning disc. Compared with a traditional single-point bearing mode, the counter weight bearing device can carry out circumferential equidistant multi-point bearing on the counter weight, can avoid relative inclination caused by single-point bearing of the counter weight on the guide rod, and avoids friction caused by the inclination angle generated by the counter weight and the guide rod, so that the service life of the counter weight is prolonged, and the service life of the counter weight is prolonged. The heavy hammer can normally and freely fall along the guide rod in the subsequent road surface detection link, the accuracy of the road surface detection result is ensured, in addition, the supporting blocks do not need to be driven one by one to rotate, the four groups of supporting blocks are linked at the same time, and locking positioning or locking positioning removal of the heavy hammer is quicker and more convenient.

Description

Technical Field

[0001] This utility model belongs to the technical field of road surface testing equipment, specifically relating to a falling weight deflectometer for road surface testing. Background Technology

[0002] As a key device for road surface testing, the falling weight deflectometer works by dropping a heavy weight from a specific height to impact the road surface and generate an instantaneous load, simulating the effect of traffic load on the road surface, and then measuring the road surface deflection value to quickly obtain road bearing capacity data, providing an important basis for road maintenance, design and construction.

[0003] A related technology (publication number CN212000529U) discloses a beam lifting device for a falling weight deflectometer, including a hydraulic press. A hydraulic column is movably connected to the top of the hydraulic press, and a beam is fixedly connected to the top of the hydraulic column. A cylinder is fixedly connected to one side of the beam, and a cylinder seat is fixedly connected to one side of the cylinder. An air inlet pipe is fixedly connected to the side of the cylinder seat away from the cylinder, and a piston is movably connected to the side of the cylinder away from the cylinder seat. This beam lifting device for a falling weight deflectometer, through the coordinated arrangement of the hydraulic column, beam, cylinder, piston, gripper, falling weight column, and slot, enables complete automation of the deflectometer and has a simple structure, solving the problem of high cost in existing deflectometers. The coordinated arrangement of the beam, piston, gripper, sleeve, falling weight column, and slot improves the reliability of the device and simplifies operation, solving the problem of low reliability in existing devices.

[0004] The structural system of a falling weight deflectometer includes key components such as a guide rod, a weight, and sensors. Currently, the lifting of the weight relies on manual movement along the guide rod. The locking and limiting mechanism for the weight typically employs a single-point positioning mode. In this mode, only a single positioning block provides single-point support for the bottom of the weight. Given the weight's own gravity, under long-term single-point support, the weight will gradually become relatively tilted on the guide rod. This tilting problem adversely affects the free-fall motion of the weight along the guide rod during subsequent road surface testing, causing friction at an angle between the inner wall of the weight and the guide rod. This interferes with the ideal path of the weight's natural fall, ultimately negatively impacting the accuracy of the test results. Utility Model Content

[0005] To address the problems in existing technologies where the hammer of a falling weight deflectometer is supported at a single point for extended periods, leading to a gradual relative tilting of the hammer on the guide rod, this present invention provides a falling weight deflectometer for road testing. This new instrument provides multi-point, equidistant support for the hammer in a circumferential manner. Compared to traditional single-point support, this avoids the relative tilting caused by single-point support, preventing friction between the hammer and guide rod and ensuring the hammer's normal free fall during subsequent road testing, thus guaranteeing the accuracy of the road test results. The specific technical solution is as follows:

[0006] A falling weight deflectometer for road surface testing includes a guide rod, a support plate, and a weight. The support plate is disposed at the bottom end of the guide rod, and the weight is slidably sleeved on the guide rod. A positioning plate is installed at the top of the weight. The area of ​​the upper surface of the positioning plate is smaller than the area of ​​its lower surface, and the centers of the upper and lower surfaces of the positioning plate are located on the same vertical line. The upper and lower surfaces of the positioning plate are connected to form an inclined end face. A fixed seat is fixedly installed at the top of the guide rod. Four slots are equidistantly formed along the circumference of the side wall of the fixed seat. A rotating shaft is rotatably connected in each slot. A positioning arm is fixedly installed on each rotating shaft. A support block is installed at the bottom end of each positioning arm. The end of the support block facing away from the positioning arm is set as an arc shape.

[0007] The position of the support block corresponds to the position of the inclined end face of the positioning disk.

[0008] In the above technical solution, a support seat is vertically and fixedly installed at the top center of the fixed seat, and four sets of springs are equidistantly installed on the side wall of the support seat along the circumference, and the four sets of springs are respectively connected to the four sets of positioning arm side walls.

[0009] In the above technical solution, the top of the support base is provided with a drive assembly for driving the four sets of positioning arms to rotate simultaneously.

[0010] The drive assembly includes a first connecting pin fixedly installed at the top of each of the positioning arms, and a rotating rod rotatably connected to the middle of the top of the support base. A turntable is fixedly installed on the rotating rod, and four sets of second connecting pins are equidistantly installed on the upper surface of the turntable along the circumference. One end of a drive rod is rotatably connected to each of the second connecting pins, and a sliding groove is provided at the other end of the drive rod.

[0011] In the above technical solution, the first connecting pin is slidably embedded in the inner cavity of the groove.

[0012] In the above technical solution, multiple handles are installed circumferentially on the side wall of the fixed seat.

[0013] In the above technical solution, the handle and the groove are positioned correspondingly.

[0014] In the above technical solution, a handwheel is installed at the top of the rotating rod.

[0015] In the above technical solution, the supporting block is perpendicular to the bottom end of the positioning arm.

[0016] The falling weight deflectometer for road surface testing disclosed in this utility model has the following advantages compared with the prior art:

[0017] I. In existing methods for supporting the hammer of a falling weight deflectometer with long-term single-point support, the hammer gradually becomes relatively tilted on the guide rod. This tilting negatively impacts the free-fall motion of the hammer along the guide rod during subsequent road surface testing, causing friction at an angle between the hammer's inner wall and the guide rod. This interferes with the ideal path of the hammer's natural fall, ultimately affecting the accuracy of the test results. This invention addresses this problem by installing four equidistantly spaced support blocks at the hammer, providing circumferential, equidistant multi-point support. Compared to traditional single-point support, this avoids the relative tilting caused by single-point support on the guide rod, preventing friction caused by the tilting angle between the hammer and the guide rod. This ensures the hammer's normal free-fall motion along the guide rod during subsequent road surface testing, guaranteeing the accuracy of the road surface testing results.

[0018] Second, the four sets of support blocks set in this utility model can rotate outward or inward simultaneously, that is, there is no need to drive the support blocks to rotate one by one. The four sets of support blocks are linked at the same time, which makes locking and unlocking the hammer faster and more convenient, with higher operating efficiency, and is more suitable for operating environments where the hammer falls freely for testing repeatedly.

[0019] Third, this utility model can simultaneously drive four sets of drive rods and four sets of positioning arms to rotate by operating the handwheel and rotating rod. This means that the four sets of support blocks at the bottom of the four sets of positioning arms can rotate at the same time, thus achieving synchronous positioning or synchronous release of the four points at the bottom of the hammer. This ensures that the bottom of the hammer receives equal support force when it is supported, and that the released hammer can fall vertically along the guide rod.

[0020] In summary, this invention provides circumferential, equidistant multi-point support for the hammer. Compared to traditional single-point support, it avoids the relative tilting of the hammer caused by single-point support on the guide rod, thus preventing friction caused by the tilting angle between the hammer and the guide rod. This ensures that the hammer undergoes normal free fall motion along the guide rod during subsequent road surface inspection, guaranteeing the accuracy of the inspection results. Furthermore, it eliminates the need to drive each support block individually; the four sets of support blocks move in unison, making locking and unlocking of the hammer faster and more convenient, resulting in higher operational efficiency. It is also more suitable for operating environments where hammers repeatedly fall freely for inspection. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the guide rod of this utility model;

[0022] Figure 2 This is a schematic diagram of the structure of the fixing base of this utility model;

[0023] Figure 3 This is a schematic diagram of the structure of the support base of this utility model;

[0024] Figure 4 This is a schematic diagram of the structure of the positioning disc of this utility model when it is detached from the support block;

[0025] Figures 1 to 4 In the middle, 1. guide rod, 2. bearing plate, 3. counterweight, 4. positioning plate, 5. fixed seat, 6. groove, 7. rotating shaft, 8. positioning arm, 9. spring, 10. support seat, 11. first connecting pin, 12. rotating rod, 13. handwheel, 14. turntable, 15. second connecting pin, 16. drive rod, 17. slide groove, 18. support block, 19. handle. Detailed Implementation

[0026] The following are specific implementation cases and appendices. Figures 1 to 4 The present invention will be further described below, but the present invention is not limited to these embodiments.

[0027] See Figures 1 to 4 As shown, a falling weight deflectometer for road surface testing includes a guide rod 1, a bearing plate 2, and a weight 3. The bearing plate 2 is disposed at the bottom end of the guide rod 1, and the weight 3 is slidably sleeved on the guide rod 1. The guide rod 1, bearing plate 2, and weight 3 are all commonly used components in existing falling weight deflectometers and represent prior art. These components are commercially available models that meet the testing requirements; therefore, no specific model limitations or further details are provided. A positioning disc 4 is mounted on the top of the weight 3. (See also...) Figure 4As shown, the area of ​​the upper surface of the positioning disk 4 is smaller than the area of ​​its lower surface, and the centers of the upper and lower surfaces of the positioning disk 4 are located on the same vertical line. The upper and lower surfaces of the positioning disk 4 are connected to form an inclined end face. A fixed seat 5 is fixedly installed at the top of the guide rod 1. Four slots 6 are equidistantly opened along the circumferential direction on the side wall of the fixed seat 5. A rotating shaft 7 is rotatably connected in each slot 6. A positioning arm 8 is fixedly installed on each rotating shaft 7. A support block 18 is installed at the bottom end of each positioning arm 8. The end of the support block 18 away from the positioning arm 8 is set as an arc shape. The support block 18 is perpendicular to the bottom end of the positioning arm 8. The position of the support block 18 corresponds to the position of the inclined end face of the positioning disk 4. A support seat 10 is vertically and fixedly installed at the middle of the top of the fixed seat 5. Four sets of springs 9 are equidistantly installed along the circumferential direction on the side wall of the support seat 10. The four sets of springs 9 are respectively connected to the side walls of the four sets of positioning arms 8.

[0028] See Figure 4 As shown, when the hammer 3 needs to be repositioned at the four sets of support blocks 18 in this state, an upward thrust is applied to the hammer 3 to make it move upward along the guide rod 1. The inclined end face of the positioning disk 4 at the top of the hammer 3 first contacts the support block 18 and continues to move upward along the arc surface of the support block 18. During this process, the positioning disk 4 causes the four sets of support blocks 18 to be forced to rotate outward about the pivot 7. At this time, the spring 9 is compressed until the positioning disk 4 is completely above the four sets of support blocks 18. With the help of the elastic force of the spring 9, the positioning arm 8 and the pivot 7 are forced to rotate in the opposite direction to return to the initial position, that is, the support block 18 at the bottom of the positioning arm 8 returns to the initial position to support the bottom of the positioning disk 4. The bottom end face of the positioning disk 4 is flat. Under the support of the four sets of support blocks 18, the positioning disk 4 and the hammer 3 can be locked and limited on the guide rod 1.

[0029] Main references Figure 2 As shown, the top of the support base 10 is provided with a drive assembly for driving four sets of positioning arms 8 to rotate simultaneously; the drive assembly includes a first connecting pin 11 fixedly installed on the top of each positioning arm 8, and a rotating rod 12 rotatably connected to the middle of the top of the support base 10 via a bearing. A handwheel 13 is installed on the top of the rotating rod 12, and a turntable 14 is fixedly installed on the rotating rod 12. Four sets of second connecting pins 15 are equidistantly installed on the upper surface of the turntable 14 along the circumferential direction. One end of a drive rod 16 is rotatably connected to each second connecting pin 15, and a groove 17 is opened on the other end of the drive rod 16; the first connecting pin 11 is slidably embedded in the inner cavity of the groove 17.

[0030] The drive handwheel 13 drives the rotating rod 12 and the turntable 14 to rotate clockwise, so that the four sets of second connecting pins 15 on the turntable 14 drive one end of the drive rod 16 to move clockwise synchronously. At this time, the first connecting pin 11 located in the inner cavity of the slide groove 17 moves towards the turntable 14 under the drive of the drive rod 16, and rotates towards the turntable 14 with the rotating shaft 7 as the axis. This causes the positioning arm 8 to rotate in the middle with the rotating shaft 7 as the axis. During this rotation, the spring 9 at the corresponding position is forced to compress, and the support block 18 at the bottom of the positioning arm 8 rotates outward to the position of being separated from the bottom of the positioning plate 4. At this time, the four sets of support blocks 18 simultaneously lose their supporting function on the positioning plate 4. The positioning plate 4 and the weight 3, which lose their limiting function, fall freely downward along the guide rod 1 under the automatic action, completing the drop hammer detection.

[0031] In addition, the main references Figure 2 As shown, multiple handles 19 are installed circumferentially on the side wall of the fixed base 5. By manually holding the handles 19, the guide rod 1 can be made to be perpendicular to the ground so as to control the position of the guide rod 1. The handles 19 are positioned in relation to the groove 6, which can ensure the normal use of the handles 19 and also leave enough room for the rotation of the positioning arm 8 in the inner cavity of the groove 6, so that the two will not interfere with each other.

[0032] The working principle of a falling weight deflectometer for road surface testing in this embodiment is as follows:

[0033] When the hammer 3 is released to allow it to fall freely down the guide rod 1 for detection, the drive handwheel 13 drives the rotating rod 12 and the turntable 14 to rotate clockwise, causing the four sets of second connecting pins 15 on the turntable 14 to drive one end of the drive rod 16 to move clockwise synchronously. At this time, the first connecting pin 11 located in the inner cavity of the slide groove 17 moves towards the turntable 14 under the drive of the drive rod 16, and rotates towards the turntable 14 with the rotating shaft 7 as the axis. This causes the positioning arm 8 to rotate in the middle with the rotating shaft 7 as the axis. During this rotation, the spring 9 at the corresponding position is forced to compress, and the support block 18 at the bottom of the positioning arm 8 rotates outward to the position away from the bottom of the positioning disk 4. At this time, the four sets of support blocks 18 simultaneously lose their supporting function on the positioning disk 4. The positioning disk 4 and the hammer 3, which have lost their limiting function, fall freely down the guide rod 1 under the automatic action, completing the hammer drop detection.

[0034] See Figure 4As shown, when the hammer 3 needs to be repositioned at the four sets of support blocks 18 in this state, an upward thrust is applied to the hammer 3 to make it move upward along the guide rod 1. The inclined end face of the positioning disk 4 at the top of the hammer 3 first contacts the support block 18 and continues to move upward along the arc surface of the support block 18. During this process, the positioning disk 4 causes the four sets of support blocks 18 to be forced to rotate outward about the pivot 7. At this time, the spring 9 is compressed until the positioning disk 4 is completely above the four sets of support blocks 18. With the help of the elastic force of the spring 9, the positioning arm 8 and the pivot 7 are forced to rotate in the opposite direction to return to the initial position, that is, the support block 18 at the bottom of the positioning arm 8 returns to the initial position to support the bottom of the positioning disk 4. The bottom end face of the positioning disk 4 is flat. Under the support of the four sets of support blocks 18, the positioning disk 4 and the hammer 3 can be locked and limited on the guide rod 1.

[0035] This invention provides circumferential, equidistant multi-point support for the hammer 3. Compared to the traditional single-point support method, it avoids the relative tilting caused by single-point support of the hammer 3 on the guide rod 1, thus preventing friction caused by the tilting angle between the hammer 3 and the guide rod 1. This ensures that the hammer 3 can perform normal free fall motion along the guide rod 1 during subsequent road surface inspection, guaranteeing the accuracy of the road surface inspection results. In addition, there is no need to drive the support blocks 18 to rotate individually. The four sets of support blocks 18 can be linked simultaneously, making it faster and more convenient to lock and unlock the hammer 3, resulting in higher operating efficiency. It is also more suitable for operating environments where the hammer 3 is repeatedly dropped for inspection.

[0036] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A falling weight deflectometer for road surface testing, comprising a guide rod (1), a bearing plate (2), and a weight (3), characterized in that: The bearing plate (2) is set at the bottom end of the guide rod (1), the hammer (3) is slidably sleeved on the guide rod (1), the top end of the hammer (3) is equipped with a positioning plate (4), the upper surface area of ​​the positioning plate (4) is smaller than the lower surface area, and the center of the upper and lower surfaces of the positioning plate (4) is located on the same vertical line. The upper and lower surfaces of the positioning plate (4) are connected to form an inclined end face. The top end of the guide rod (1) is fixedly installed with a fixing seat (5). The side wall of the fixing seat (5) is provided with four slots (6) equidistantly along the circumference. Each slot (6) is rotatably connected with a rotating shaft (7). Each rotating shaft (7) is fixedly installed with a positioning arm (8). Each positioning arm (8) is respectively equipped with a support block (18) at the bottom end. The end of the support block (18) away from the positioning arm (8) is set as an arc shape. The position of the support block (18) corresponds to the position of the inclined end face of the positioning disk (4).

2. The falling weight deflectometer for road surface testing according to claim 1, characterized in that: The top center of the fixed seat (5) is vertically and fixedly installed with a support seat (10). The side wall of the support seat (10) is equidistantly installed with four sets of springs (9) along the circumferential direction. The four sets of springs (9) are respectively connected to the side walls of the four sets of positioning arms (8).

3. A falling weight deflectometer for road surface testing according to claim 2, characterized in that: The top of the support base (10) is provided with a drive assembly for driving the four sets of positioning arms (8) to rotate simultaneously. The drive assembly includes a first connecting pin (11) fixedly installed at the top of each of the positioning arms (8), and a rotating rod (12) rotatably connected to the middle of the top of the support base (10). A turntable (14) is fixedly installed on the rotating rod (12). Four sets of second connecting pins (15) are equidistantly installed on the upper surface of the turntable (14) along the circumferential direction. One end of a drive rod (16) is rotatably connected to each of the second connecting pins (15). A groove (17) is provided at the other end of the drive rod (16).

4. A falling weight deflectometer for road surface testing according to claim 3, characterized in that: The first connecting pin (11) is slidably embedded in the inner cavity of the groove (17).

5. A falling weight deflectometer for road surface testing according to claim 1, characterized in that: The fixed base (5) has multiple handles (19) installed circumferentially on its side wall.

6. A falling weight deflectometer for road surface testing according to claim 5, characterized in that: The handle (19) is positioned corresponding to the groove (6).

7. A falling weight deflectometer for road surface testing according to claim 3, characterized in that: A handwheel (13) is installed at the top of the rotating rod (12).

8. A falling weight deflectometer for road surface testing according to claim 1, characterized in that: The support block (18) is perpendicular to the bottom end of the positioning arm (8).

Images