A self-calibration type soil liquid-plastic limit tester

Abstract

The application relates to the technical field of geotechnical test detection equipment, and discloses a self-calibration type soil liquid-plastic limit tester which comprises an equipment rack, a detection top needle and a self-adaptive contraction calibration device. The self-adaptive contraction calibration device is matched with a lifting bearing table, and automatic centering correction is realized by relying on a correction device assembled in a base. The correction device drives vertical displacement of an upper and lower connecting plate through a cylinder, forms a fixed-point swing transmission structure in cooperation with a supporting block, a triangular movable plate and an elliptical rod, drives a plurality of arc-shaped clamping structures to be synchronously contracted or expanded, adaptively clamps the outer walls of test cups of different specifications, automatically completes centering calibration, and eliminates the problem of eccentric offset of the test cup. Meanwhile, the working height can be flexibly adjusted through a lifting column to adapt to different test working conditions. The application can realize automatic and accurate alignment of the test cup, ensure that the cone is vertically inserted into the soil, effectively eliminate detection errors, and improve test precision and test efficiency.

Description

Technical Field

[0001] This invention relates to the field of geotechnical testing equipment technology, specifically a self-calibrating soil liquid and plastic limit tester. Background Technology

[0002] Soil liquid and plastic limit testing is a core test item in geotechnical engineering investigation and roadbed construction testing. Its testing accuracy directly determines the accuracy of soil classification and foundation construction parameters.

[0003] Existing soil liquid and plastic limit testers have significant drawbacks in use. Conventional equipment lacks a dedicated adaptive centering and correction structure, and test cups often rely on manual placement and positioning, which easily leads to offset and eccentricity issues. Test cup offset directly causes the testing cone to tilt into the soil, disrupting the standard vertical insertion condition and resulting in large errors in soil depth detection and poor test repeatability.

[0004] Meanwhile, traditional equipment has a fixed clamping structure, which cannot adaptively adapt to test cups of different outer diameters. After changing the test cup, repeated manual alignment and calibration are required, which is cumbersome and prone to errors due to human intervention. In addition, the height adjustment of the conventional bearing platform is poorly adaptable and cannot match the requirements of different sample thicknesses and testing strokes, further affecting the standardization and accuracy of the test, making it difficult to meet the current needs of high-precision, automated, and standardized geotechnical testing. Summary of the Invention

[0005] The purpose of this invention is to provide a self-calibrating soil liquid and plastic limit tester to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a self-calibrating soil liquid and plastic limit tester, comprising an equipment frame, a detection pin, and an adaptive shrinkage calibration device. The detection pin is vertically fixed to the upper part of the equipment frame, and the adaptive shrinkage calibration device is correspondingly arranged directly below the detection pin for adaptive centering correction and fixing of the test cup.

[0007] The adaptive shrinkage calibration device includes a base, a correction device, and a lifting support platform;

[0008] The base has a hollow mounting cavity in the middle, and the correction device is assembled inside the hollow mounting cavity of the base to realize the self-adaptive correction and centering fixation of the test cup.

[0009] The correction device includes a drive device and a movable displacement device. The drive device is fixedly installed inside the hollow mounting cavity of the base, and the movable displacement device is connected to the drive device in a transmission manner.

[0010] The drive device is used to provide power to drive the movable displacement device to perform radial telescopic displacement motion.

[0011] The movable displacement device is a telescopic clamp arranged on all four sides, which can simultaneously retract inward and expand outward. By fitting and clamping the outer surface of the test cup, it adaptively limits and fixes test cups of different specifications, and automatically calibrates the position of the test cup, so that the center of the test cup is precisely aligned with the bottom of the detection pin, completely eliminating the problem of test cup placement being off-center or offset.

[0012] The bottom of the lifting support platform corresponds to the outside of the correction device and is located directly below the detection pin.

[0013] As a preferred embodiment of the present invention, the driving device includes a first connecting plate, a cylinder is fixedly connected to the bottom center of the first connecting plate, the output shaft of the cylinder vertically passes through the center of the first connecting plate, and a second connecting plate is fixedly connected to the top of the output shaft of the cylinder, the second connecting plate being arranged parallel above the first connecting plate.

[0014] As a preferred embodiment of the present invention, a first support block is fixedly connected to each of the four top corners of the first connecting plate, and a second support block is fixedly connected to each of the four bottom corners of the second connecting plate. The first support block and the second support block are vertically aligned in a one-to-one correspondence, and both the first support block and the second support block are connected to the movable displacement device for transmission.

[0015] As a preferred embodiment of the present invention, the movable displacement device includes four triangular movable plates, each of which has a groove at its bottom. A rotating shaft is movably connected inside each groove, and the center of the rotating shaft is fixedly connected to the second support block.

[0016] As a preferred embodiment of the present invention, a fixed plate is hinged to the top inner side of each of the four triangular movable plates, and an elliptical rod is hinged to both sides of each fixed plate. The bottom end of the elliptical rod is hinged to the top two sides of the corresponding first support block.

[0017] As a preferred embodiment of the present invention, a semi-circular arc plate is fixedly connected to the top of each of the four fixing plates, and anti-slip bonding texture is provided on the inner side of each of the four semi-circular arc plates. The four semi-circular arc plates surround to form a variable diameter clamping cavity, which is used to fit and clamp the outer wall of test cups with different outer diameters.

[0018] As a preferred embodiment of the present invention, the lifting support platform includes four lifting columns, which are respectively arranged on the outside of the first support block, and the top of the four lifting columns are fixedly connected to a placement platform.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] (1) A self-calibrating soil liquid and plastic limit tester, which precisely drives the second connecting plate fixed at the top to move vertically up and down by extending and retracting the cylinder output shaft. During the movement, the second connecting plate can simultaneously drive the second support block fixed at the four corners to move as a whole, providing a stable and uniform power input for the swinging and shrinking of the subsequent clamping structure.

[0021] (2) A self-calibrating soil liquid and plastic limit tester, wherein the first and second connecting plates are arranged symmetrically in parallel, and the first and second support blocks at the four corners form a frame support structure, which has strong overall rigidity and uniform stress distribution. During the vertical drive of the cylinder, the upper and lower support structures can effectively offset the lateral stress, avoid deformation and displacement of the transmission structure, and ensure that the second support block only makes precise vertical displacement without lateral swaying, which greatly improves the long-term stability and service life of the equipment and reduces equipment failure and calibration error.

[0022] (3) A self-calibrating soil liquid and plastic limit tester, which achieves fixed-point swing transmission by relying on the hinged connection between the bottom groove of the triangular movable plate and the rotating shaft, and utilizing the connection relationship between the center of the rotating shaft and the second support block. When the second support block is pulled vertically, only one end of the bottom of the triangular movable plate moves with the rotating shaft, while the other end of the bottom of the triangular movable plate and the bottom end of the elliptical rod are hinged and fixed to the first support block to form a fixed fulcrum. Only the end of the rotating shaft can move, while the rest of the structure swings at a fixed point, completely eliminating the misalignment and offset of the clamping structure, ensuring that the trajectory of each contraction and expansion is completely consistent, and the calibration accuracy is stable and controllable.

[0023] (4) A self-calibrating soil liquid and plastic limit tester, which, through the action of four triangular movable plates swinging at a fixed point, can synchronously drive the fixed plate on the inner side of the top and the semi-circular arc plate to synchronously retract or expand. The four semi-circular arc plates enclose to form a variable diameter clamping cavity, which, together with the anti-slip texture on the inner side, can tightly fit and clamp the outer wall of test cups of different outer diameter specifications. Through four-way synchronous equidistant contraction, the test cup is automatically centered and positioned, completely solving the problem of eccentricity and offset when manually placing the test cup, so that the center of the test cup is always accurately aligned with the bottom of the testing pin, and the phenomenon of the cone tilting into the soil is eliminated.

[0024] (5) A self-calibrating soil liquid and plastic limit tester, which can stably drive the fixedly connected placement platform at the top to make precise adjustments to multiple positions and different heights through the synchronous telescopic movement of four lifting columns. It can flexibly adjust the working height of the overall bearing platform according to the height of the test cups of different specifications, the thickness of the soil sample filling, and the requirements of the conical detection stroke. The multi-column synchronous support lifting structure has uniform force distribution and smooth lifting without tilting, which can always ensure the levelness of the placement platform and the coaxial calibration accuracy of the test cup. Attached Figure Description

[0025] Figure 1 This is a front view of the present invention.

[0026] Figure 2 This is a schematic diagram of the overall adaptive shrinkage calibration device of the present invention;

[0027] Figure 3 This is a schematic diagram of the overall corrective device of the present invention;

[0028] Figure 4 This is a schematic diagram of the driving device of the present invention;

[0029] Figure 5 This is a schematic diagram of the movable displacement device of the present invention;

[0030] Figure 6 This is a schematic diagram showing the connection relationship between the triangular movable plate and the first support block of the present invention;

[0031] Figure 7 This is a schematic diagram of the lifting support platform of the present invention.

[0032] In the diagram: 1. Equipment frame; 2. Detection pin; 3. Adaptive shrinkage calibration device; 31. Base; 32. Correction device; 321. Drive device; 3211. First connecting plate; 3212. Cylinder; 3213. Second connecting plate; 3214. First support block; 3215. Second support block; 322. Movable displacement device; 3221. Triangular movable plate; 3222. Groove; 3223. Rotating shaft; 3224. Fixed plate; 3225. Elliptical rod; 3226. Semi-circular arc plate; 33. Lifting support platform; 331. Lifting column; 332. Placement platform. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Example: Please refer to Figure 1-2 A self-calibrating soil liquid and plastic limit tester includes an equipment frame 1, a detection pin 2, and an adaptive shrinkage calibration device 3. The detection pin 2 is vertically fixed to the upper part of the equipment frame 1, and the adaptive shrinkage calibration device 3 is correspondingly arranged directly below the detection pin 2 for adaptive centering correction and fixing of the test cup.

[0035] The adaptive shrinkage calibration device 3 includes a base 31, a correction device 32, and a lifting support platform 33;

[0036] The base 31 has a hollow mounting cavity in the middle, and the correction device 32 is assembled inside the hollow mounting cavity of the base 31 to realize the self-adaptive correction and centering fixation of the test cup.

[0037] The correction device 32 includes a drive device 321 and a movable displacement device 322. The drive device 321 is fixedly installed inside the hollow mounting cavity of the base 31, and the movable displacement device 322 is connected to the drive device 321 in a transmission manner.

[0038] The drive device 321 is used to provide power to drive the movable displacement device 322 to perform radial telescopic displacement motion.

[0039] The movable displacement device 322 is a telescopic clamp arranged on all four sides. It can simultaneously retract inward and expand outward. By fitting and clamping the outer surface of the test cup, it adaptively limits and fixes test cups of different specifications, and automatically calibrates the position of the test cup, so that the center of the test cup is precisely aligned with the bottom of the detection pin 2, completely eliminating the problem of test cup placement being off-center or offset.

[0040] The bottom of the lifting support platform 33 corresponds to the outer side of the correction device 32 and is located directly below the detection pin 2.

[0041] Example 2: Based on Example 1, as follows Figure 3-7 As shown, the driving device 321 includes a first connecting plate 3211. A cylinder 3212 is disposed at the bottom center of the first connecting plate 3211, and the bottom center of the first connecting plate 3211 is fixedly connected to the outer surface of the cylinder 3212. The output shaft of the cylinder 3212 vertically penetrates the center of the first connecting plate 3211. A second connecting plate 3213 is disposed at the top of the output shaft of the cylinder 3212, and the top of the output shaft of the cylinder 3212 is fixedly connected to the bottom center of the second connecting plate 3213. The second connecting plate 3213 is disposed parallel to the top of the first connecting plate 3211. By vertically extending and retracting the output shaft of the cylinder 3212, the second connecting plate 3213 fixed at the top is precisely driven to move vertically up and down. During the movement, the second connecting plate 3213 can simultaneously drive the second support blocks 3215 fixed at the four corners to move as a whole, providing a stable and uniform power input for the subsequent swinging and contraction of the clamping structure.

[0042] Each of the four top corners of the first connecting plate 3211 is provided with a first support block 3214, and the four top corners of the first connecting plate 3211 are fixedly connected to the bottom of the first support block 3214. Each of the four bottom corners of the second connecting plate 3213 is provided with a second support block 3215, and the four bottom corners of the second connecting plate 3213 are fixedly connected to the bottom of the second support block 3215. The first support blocks 3214 and the second support blocks 3215 are vertically aligned in a one-to-one correspondence, and both the first support blocks 3214 and the second support blocks 3215 are connected to the movable displacement device 322 for transmission. The first connecting plate 3211 and the second connecting plate 3213 are arranged in parallel and symmetrical arrangement, and together with the corresponding first support blocks 3214 and second support blocks 3215 at the four corners, they form a frame-type support structure with high overall structural rigidity and uniform stress distribution. During the vertical drive of cylinder 3212, the upper and lower support structures can effectively offset lateral stress, prevent deformation and displacement of the transmission structure, and ensure that the second support block 3215 only makes precise vertical displacement without left and right swaying. This greatly improves the long-term stability and service life of the equipment and reduces equipment failure and calibration errors.

[0043] The movable displacement device 322 includes four triangular movable plates 3221. Each of the four triangular movable plates 3221 has a groove 3222 at its bottom. Each set of grooves 3222 has a rotating shaft 3223 inside, and each set of grooves 3222 is movably connected to both ends of the rotating shaft 3223. The center of the rotating shaft 3223 is fixedly connected to the second support block 3215.

[0044] Each of the four triangular movable plates 3221 has a fixed plate 3224 on its top inner side, and the top inner side of each of the four triangular movable plates 3221 is hinged to the bottom end of the fixed plate 3224. Each fixed plate 3224 has an elliptical rod 3225 on both sides, and the top inner side of the top of each fixed plate 3224 is hinged to the bottom of the elliptical rod 3225. The bottom end of the elliptical rod 3225 is hinged to the top two sides of the corresponding first support block 3214. By relying on the hinged connection between the bottom groove 3222 of the triangular movable plate 3221 and the rotating shaft 3223, and utilizing the connection relationship between the center of the rotating shaft 3223 and the second support block 3215, fixed-point swing transmission is achieved. When the second support block 3215 is pulled vertically, only one end of the bottom of the triangular movable plate 3221 moves with the rotation shaft 3223. At the same time, the other end of the bottom of the triangular movable plate 3221 and the bottom end of the elliptical rod 3225 are hinged and fixed to the first support block 3214, forming a fixed fulcrum. Only the end of the rotation shaft 3223 can move, while the rest of the structure swings at a fixed point, completely eliminating the misalignment and offset of the clamping structure, ensuring that the trajectory of each contraction and expansion is completely consistent, and the calibration accuracy is stable and controllable.

[0045] Each of the four fixing plates 3224 has a semi-circular arc plate 3226 at its top, and the top of each fixing plate 3224 is fixedly connected to the bottom of the semi-circular arc plate 3226. The inner side of each of the four semi-circular arc plates 3226 has anti-slip textured surfaces. The four semi-circular arc plates 3226 together form a variable-diameter clamping cavity for clamping test cups of different outer diameters. Through the fixed-point swinging action of the four triangular movable plates 3221, the top inner fixing plate 3224 and the semi-circular arc plate 3226 can be simultaneously moved to retract or expand. The four semi-circular arc plates 3226 together form a variable-diameter clamping cavity, which, combined with the inner anti-slip textured surfaces, can tightly clamp test cups of different outer diameters. By using four-way synchronous equidistant contraction, the test cup is automatically centered and positioned, completely solving the problem of eccentricity and offset when manually placing the test cup. This ensures that the center of the test cup is always accurately aligned with the bottom of the testing pin 2, eliminating the phenomenon of the cone tilting into the soil.

[0046] The lifting platform 33 includes four lifting columns 331, which are respectively arranged on the outside of the first support block 3214. The top of the four lifting columns 331 is fixedly connected to the placement platform 332. Through the synchronous extension and retraction of the four lifting columns 331, the placement platform 332 fixedly connected to the top can be stably driven to make precise adjustments to multiple positions and different heights. The overall working height of the platform can be flexibly adjusted according to the height of the test cups of different specifications, the thickness of the soil sample filling, and the requirements of the conical test stroke. The multi-column synchronous support lifting structure has uniform force distribution and smooth lifting without tilting, which can always ensure the levelness of the placement platform 332 and the coaxial calibration accuracy of the test cups.

[0047] The working principle of this invention is as follows:

[0048] During operation, the entire equipment relies on the equipment frame 1 as the supporting base. The detection pin 2 is vertically fixed on the upper part of the equipment frame 1 as a coaxial detection reference. The adaptive shrinkage calibration device 3 is set directly below the detection pin 2. Before the test begins, the operator places the test cup containing the soil sample at the center of the placement platform 332 of the lifting support platform 33. Then, the equipment is started, and the drive device 321 inside the correction device 32 starts to work. The cylinder 3212 fixed at the bottom center of the first connecting plate 3211 in the drive device 321 is started. The output shaft of the cylinder 3212 extends and retracts vertically and drives the second connecting plate 3213 fixed at the top to move vertically up and down. The second connecting plate 3213, which is parallel to the first connecting plate 3211, drives the second support block 3215 fixed at the four corners of its bottom to move up and down in sync during the vertical displacement.

[0049] The second support block 3215 forms a transmission connection with the triangular movable plate 3221 in the movable displacement device 322 through the rotating shaft 3223. Since the bottom of the triangular movable plate 3221 is movably connected to both ends of the rotating shaft 3223 through the groove 3222 and the center of the rotating shaft 3223 is fixedly connected to the second support block 3215, and the fixed plate 3224 hinged to the inner side of the top of the triangular movable plate 3221 is hinged to the top two sides of the first support block 3214 fixed at the top four corners of the first connecting plate 3211 through the elliptical rod 3225, the triangular movable plate 3221 can only swing at a fixed point with one end of the rotating shaft 3223, while the rest of the structure remains fixed and unsupported.

[0050] When the second support block 3215 pulls or pushes the bottom of the triangular movable plate 3221 vertically, the four triangular movable plates 3221 swing inward or outward at fixed points simultaneously, thereby simultaneously driving the top fixed plate 3224 and the semi-circular arc plate 3226 fixed at the top of the fixed plate 3224 to retract or expand simultaneously. The four semi-circular arc plates 3226 with anti-slip texture on the inner side enclose to form a variable diameter clamping cavity, which adaptively fits and clamps the outer wall of test cups with different outer diameter specifications.

[0051] The automatic centering calibration of the test cup is achieved by using four-way synchronous equidistant contraction, ensuring that the center of the test cup is always precisely aligned with the bottom of the testing pin 2, completely eliminating the problem of test cup eccentricity and offset. At the same time, the lifting support platform 33 can be synchronously extended and retracted by four lifting columns 331 arranged outside the first support block 3214, stably driving the fixed placement platform 332 at the top to perform multi-level height adjustment. The working height can be flexibly adjusted according to the height of the test cup, the thickness of the sample, and the testing stroke requirements. Moreover, the multi-column synchronous lifting structure can always ensure the levelness of the placement platform 332. Combined with the coaxial alignment function of the adaptive contraction calibration device 3, it ensures that the conical testing component is always vertically aligned with the center of the test cup and vertically inserted into the soil, effectively avoiding the testing deviation caused by the cone tilting into the soil. Finally, the displacement detection module accurately collects the soil penetration depth data, completing the standardized and high-precision testing of the soil liquid limit and plastic limit.

[0052] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A self-calibrating soil liquid and plastic limit tester, comprising a frame (1), a detection pin (2), and an adaptive shrinkage calibration device (3), characterized in that: The detection pin (2) is vertically fixed to the upper part of the equipment frame (1), and the adaptive shrinkage calibration device (3) is correspondingly set directly below the detection pin (2). The adaptive shrinkage calibration device (3) includes a base (31), a correction device (32), and a lifting support platform (33). The base (31) has a hollow mounting cavity in the middle, and the correction device (32) is assembled inside the hollow mounting cavity of the base (31); The correction device (32) includes a drive device (321) and a movable displacement device (322). The drive device (321) is fixedly installed inside the hollow mounting cavity of the base (31), and the movable displacement device (322) is connected to the drive device (321) in a transmission manner. The drive device (321) is used to provide power to drive the movable displacement device (322) to perform radial telescopic displacement movement; The movable displacement device (322) is a telescopic clamp arranged on all four sides, which can simultaneously retract inward and expand outward, so that the center of the test cup is precisely aligned with the bottom of the detection pin (2), completely eliminating the problem of test cup placement being off-center or offset; The bottom of the lifting support platform (33) corresponds to the outside of the correction device (32) and is located directly below the detection pin 2.

2. The self-calibrating soil liquid and plastic limit tester according to claim 1, characterized in that: The driving device (321) includes a first connecting plate (3211), a cylinder (3212) is fixedly connected to the bottom center of the first connecting plate (3211), the output shaft of the cylinder (3212) vertically passes through the center of the first connecting plate (3211), and a second connecting plate (3213) is fixedly connected to the top of the output shaft of the cylinder (3212), the second connecting plate (3213) is arranged parallel above the first connecting plate (3211).

3. The self-calibrating soil liquid and plastic limit tester according to claim 2, characterized in that: The first connecting plate (3211) has a first support block (3214) fixedly connected to each of the four top corners, and the second connecting plate (3213) has a second support block (3215) fixedly connected to each of the four bottom corners. The first support block (3214) and the second support block (3215) are arranged vertically in a one-to-one correspondence, and the first support block (3214) and the second support block (3215) are both connected to the movable displacement device (322) in a transmission connection.

4. The self-calibrating soil liquid and plastic limit tester according to claim 3, characterized in that: The movable displacement device (322) includes four triangular movable plates (3221). The bottom of each of the four triangular movable plates (3221) is provided with a groove (3222). A rotating shaft (3223) is movably connected inside each groove (3222). The center of the rotating shaft (3223) is fixedly connected to the second support block (3215).

5. A self-calibrating soil liquid and plastic limit tester according to claim 4, characterized in that: Each of the four triangular movable plates (3221) has a fixed plate (3224) hinged to its top inner side. Each fixed plate (3224) has an elliptical rod (3225) hinged to both sides. The bottom end of the elliptical rod (3225) is hinged to the top two sides of the first support block (3214) at the corresponding position.

6. A self-calibrating soil liquid and plastic limit tester according to claim 5, characterized in that: The top of each of the four fixed plates (3224) is fixedly connected to a semi-circular arc plate (3226). The inner side of each of the four semi-circular arc plates (3226) is provided with anti-slip bonding texture. The four semi-circular arc plates (3226) together form a variable diameter clamping cavity.

7. The self-calibrating soil liquid and plastic limit tester according to claim 1, characterized in that: The lifting support platform (33) includes four lifting columns (331), which are respectively arranged on the outside of the first support block (3214). The top of the four lifting columns (331) are fixedly connected to the placement platform (332).

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