Mechanical testing device and method for coal rock load

Abstract

The invention belongs to the technical field of coal rock mechanical property testing, particularly relates to a mechanical testing device and method for coal rock loading, and solves the problems that an existing device is single in function, fragments splash, cleaning is inconvenient, and protection and cleaning are not linked. The device comprises a supporting mechanism, and a modular loading mechanism is detachably mounted on the supporting mechanism and comprises a static extrusion loading module and a dynamic impact loading module; the linkage type protection mechanism is provided with two protection half barrels, and fragments can be prevented from splashing when the two protection half barrels are closed; the sweeping mechanism is started when the protective half barrels are unfolded, a rotating ring drives a Z-shaped plate to rotate, an annular inclined panel is driven to vibrate, and fragments are swept; the device integrates a static extrusion function and a dynamic impact function, so that the equipment utilization rate and the application range are improved; protection and cleaning are linked, safety is guaranteed, cross contamination is avoided, and the experiment accuracy and efficiency are improved.

Description

Technical Field

[0001] This invention relates to the field of coal and rock mechanical property testing technology, and in particular to a mechanical testing device and method for coal and rock under load. Background Technology

[0002] Coal is the core of my country's energy supply. In-depth research on the mechanical properties of coal and its dynamic damage evolution under load is crucial for promoting the fine separation of coal and the sustainable development of resources.

[0003] In existing technologies, the mechanical properties of coal and rock are typically tested by applying pressure to the sample using a press. However, such devices generally have the following problems: First, their function is limited and they are difficult to adapt to different experimental requirements such as splitting, shearing, and compression; second, when coal and rock undergo brittle fracture under pressure, fragments will fly at high speed, posing a safety hazard; and finally, after the experiment, the cleaning of the broken samples is cumbersome, requires manual operation, and is inefficient.

[0004] Therefore, there is an urgent need for a detection device that is highly integrated and automated, capable of simultaneously addressing multiple damage modes, dynamic safety protection, and automated debris recycling and cleaning. Summary of the Invention

[0005] The development of this invention stems from practical needs in the field of coal and rock mechanics testing: In coal mine resource development, understanding the mechanical behavior of coal and rock under static compression and dynamic impact is crucial. However, existing devices are often single-function, unable to flexibly switch modes, and the flying debris during testing poses safety hazards. Manual cleaning can easily lead to sample contamination, affecting experimental accuracy and efficiency. A detachable loading mechanism was developed to adapt to different testing scenarios: the static compression module provides continuous pressure through a hydraulic cylinder, while the dynamic impact module uses an electromagnet to control the height and achieve adjustable potential energy. A T-slot and positioning pin snap-fit ​​structure enables quick replacement of the pressure plate, reducing downtime and improving equipment utilization.

[0006] To combat flying debris, two protective semi-buckets are driven together by a worm gear to form a protective barrel that blocks high-speed debris. Tension springs ensure synchronized height adjustment as the base plate moves, preventing protective failure. When the protective barrier unfolds, a drive ring and Z-shaped plate vibrate the annular inclined panel, guiding the debris to the discharge port. Compared to existing technologies (such as single loading devices), this design improves safety and efficiency, avoids contamination caused by human intervention, and ensures the reliability of test data.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A mechanical testing device for coal and rock under load, comprising a support mechanism; It also includes: a modular loading mechanism, which is detachably mounted on the support mechanism for applying loads to the coal and rock samples within the support mechanism; It also includes a linkage protection mechanism and a cleaning mechanism, wherein: the protection mechanism includes two protective half-buckets and a rotating component for driving the two protective half-buckets to open or close, and the two protective half-buckets close to prevent fragments from scattering after the coal and rock sample is broken. The cleaning mechanism is located at the support mechanism and includes an annular inclined plate and a rotating ring; it can drive the cleaning mechanism when the two protective half-buckets are unfolded and reset.

[0008] In one possible design, the support mechanism includes a worktable with two guide rods fixed to the top of the worktable. The top ends of the two guide rods are fixed to the same top seat, and a hydraulic cylinder I is fixedly inserted inside the top seat. An electromagnet is fixed to the output shaft of the hydraulic cylinder I. A control box is provided on the top of the worktable, and a control panel is provided on one side of the worktable. The control box is electrically connected to the control panel, and the control panel is used to control the rotating components and the modular loading mechanism.

[0009] In one possible design, the modular loading mechanism includes a static compression loading module and a dynamic impact loading module; The static extrusion loading module includes a base plate set on the top of the workbench, a pressure plate II on the top of the base plate, and a snap-fit ​​structure between the base plate and the pressure plate II for stably mounting the pressure plate II on the top of the base plate. The top of the pressure plate II is used to place coal and rock samples. A hydraulic cylinder II is fixedly inserted through the workbench, and the output shaft of the hydraulic cylinder II is fixedly connected to the bottom of the base plate for applying static or quasi-static pressure to the coal and rock samples. A displacement sensor is fixedly inserted inside the workbench, and the movable end of the displacement sensor is fixedly connected to the bottom of the base plate for detecting the displacement distance of the base plate. The dynamic impact loading module includes a pressure plate I. The outer walls of the two guide rods are slidably fitted with the same top plate. The pressure plate I is set at the bottom of the top plate through a connecting structure. A connecting block is fixed to the top of the top plate. A pressure sensor is fixedly embedded at the bottom of the connecting block, and the bottom of the pressure sensor abuts against the top of the top plate. A magnetic attraction force is generated between the electromagnet and the iron sheet layer installed on the top of the connecting block. The hydraulic cylinder I can adjust the top plate and the pressure plate I to different heights to obtain the corresponding impact potential energy through the magnetic attraction force between the electromagnet and the connecting block. The control panel is electrically connected to the electromagnet, hydraulic cylinder II and hydraulic cylinder I, and the pressure sensor and displacement sensor are electrically connected to the control box.

[0010] In one possible design, the snap-fit ​​structure includes multiple positioning pins and positioning slots. The multiple positioning pins are fixed to the bottom of the pressure plate II, and the multiple positioning slots are set on the top of the base plate. The positioning pins and positioning slots are inserted and engaged to stably install the pressure plate II on the top of the base plate.

[0011] In one possible design, the connecting structure includes two T-shaped grooves at the bottom of the top plate, each containing a T-shaped block slidably connected to it. Both T-shaped blocks are fixed to the top of the pressure plate I. Each T-shaped block has a retaining groove on its opposite side. The top plate contains two hydraulic grooves I, each containing a piston plate that is slidably and sealed. Each piston plate has a retaining rod fixed on its opposite side. The retaining rods extend slidably and sealed into corresponding T-shaped grooves and engage with corresponding retaining grooves to fix the T-shaped blocks. A tension spring I is fitted onto the outer wall of each retaining rod. The two ends of the tension spring I abut against one side of the piston plate and the inner wall of one side of the hydraulic groove I respectively through spring seats. The top of the top plate is provided with two hydraulic grooves II, and both hydraulic grooves II are connected to the corresponding hydraulic grooves I. The hydraulic grooves II are located on the side of the piston plate near the T-shaped groove. A pressing block is sealed and slidably connected inside the hydraulic groove II. The outer walls of the two guide rods are fixedly fitted with fixing rings, and the fixing rings cooperate with the pressing blocks to press the pressing blocks into the hydraulic grooves II and disengage the clamping rods from the clamping grooves when the top plate moves up. The magnetic attraction between the electromagnet and the connecting block is greater than the tension of the tension spring I and the sum of the weight of the top plate and the pressure plate I.

[0012] In one possible design, the protective mechanism further includes two rotating shafts that rotate on the top of the workbench. The outer walls of the two rotating shafts are fixedly fitted with rotating arms. The ends of the two rotating arms that are far apart from each other are slidably connected to the corresponding protective half-buckets. One side of each of the two protective half-buckets is fixed with a vertical rod through a base. The vertical rod slides through the corresponding rotating arm. The outer wall of the vertical rod is fitted with a tension spring II. The top and bottom ends of the tension spring II are fixedly connected to the outer wall of the vertical rod and the top of the rotating arm, respectively, through spring seats. The two protective half-buckets are closed to form a protective barrel.

[0013] In one possible design, the rotating assembly includes two worm gears, which are respectively fixedly sleeved on the outer walls of two rotating shafts. A worm located between the two worm gears is rotatably connected to the top of the worktable via a base. The worm meshes with the two worm gears and drives them to rotate in opposite directions to drive the two protective half-barrels to close or open. A drive motor is fixed to the top of the worktable via a frame. The output shaft of the drive motor is fixedly connected to one end of the worm via a coupling. The drive motor is electrically connected to the control panel.

[0014] In one possible design, the cleaning mechanism further includes multiple hemispheres, which are fixedly arranged in a ring around the base plate on the top of an annular inclined panel. The bottom of the annular inclined panel is fixed to the top of the worktable, and the top of the annular inclined panel slides against the outer wall of the base plate. A rotating ring rotates on the top of the worktable, forming an annular gap between the rotating ring, the annular inclined panel, and the worktable to store debris rolling off the annular inclined panel. Multiple Z-shaped plates are fixed to the inner wall of the rotating ring and slide within the annular gap. The worktable has a discharge hole communicating with the annular gap. The rotating ring drives the Z-shaped plates to rotate, discharging the debris from the annular gap through the discharge hole. One bottom side of the Z-shaped plate abuts against the top of the annular inclined panel. The spheres are designed to work together to drive the annular inclined plate to vibrate and dislodge fragments when the rotating ring drives the Z-shaped plate to rotate. The top of the base plate has a slope to guide fragments of the coal and rock sample onto the annular inclined plate after they fall from the pressure plate II. The outer wall of the rotating ring has an annular groove, and a bevel gear ring is fixed to the inner top wall of the annular groove. One end of the worm gear is fixed to a fixed shaft, and a one-way bearing is fitted on the outer wall of the fixed shaft. The inner ring of the one-way bearing is fixed to the outer wall of the fixed shaft, and a bevel gear is fixed to the outer ring of the one-way bearing. The bevel gear meshes with the bevel gear ring. When the fixed shaft reciprocates, the one-way bearing allows the bevel gear to rotate in one direction, thereby driving the rotating ring to rotate in one direction.

[0015] In one possible design, residual gears are slidably fitted onto the outer walls of both rotating shafts via grooves and sliders. A protective housing is slidably mounted on the top of the worktable via a slide rod, located below the rotating arm. Both residual gears rotate within the protective housing. The rotating shafts penetrate the protective housing. A collar is slidably fitted onto the outer wall of one of the guide rods, and a moving rod slides through the collar. The moving rod slides through the protective housing. Racks are fixed on both sides of the moving rod, and the two racks intermittently mesh with the two residual gears respectively. A push plate is fixed at one end near the base plate. A tension spring III is sleeved on the outer wall of the moving rod. The two ends of the tension spring III are fixedly connected to the collar and the push plate respectively through spring seats, which is used to reset the moving rod and the push plate. A vertical groove is provided in the guide rod located inside the collar, which is used to allow the moving rod to move up and down. A fixing rod is fixed on the outer wall of the base plate. A sliding ring is fixed on the top of the fixing rod, and the top of the sliding ring abuts against the bottom of the collar, which is used to drive the collar to move synchronously when the base plate moves up to perform static compression. The sliding ring is slidably sleeved on the outer wall of the corresponding guide rod.

[0016] In existing technologies, the loading module, protective mechanism, and cleaning mechanism are mostly designed independently, requiring manual switching of loading modes and activation of protection and cleaning, which is cumbersome and inefficient. This invention achieves rapid switching of loading modes through modular design and automates the testing process through the linkage of protection and cleaning. The organic combination of these three components not only simplifies operation but also avoids waiting time between different stages, thus improving experimental efficiency.

[0017] This application discloses a testing method for a mechanical testing device used for coal and rock under load, comprising the following steps: S1. Module Installation: According to the test objectives, the static extrusion module and dynamic impact module are installed on the base plate and top plate. Specifically, the output shaft of hydraulic cylinder I moves the top plate upwards via the magnetic attraction of the electromagnet and connecting block. The fixing ring extrudes the extrusion block, which injects hydraulic oil from hydraulic groove II into hydraulic groove I. Under the action of the hydraulic oil, hydraulic groove I and the locking rod move away from the T-slot, causing the locking groove to disengage from the T-slot. Then, the two T-blocks on the top of pressure plate I slide into the corresponding T-slots. The output shaft of hydraulic cylinder I pushes the top plate downwards, the collar loses the extrusion force of the fixing ring, and the piston plate resets under the tension of tension spring I. The locking rod extends into the locking groove to fix the T-blocks. Finally, the multiple positioning pins at the bottom of pressure plate II are aligned with the positioning slots and inserted, completing the installation of the base plate and pressure plate II. Furthermore, the static extrusion module or dynamic impact module can be switched as needed. S1.1 During static extrusion, the output shaft of hydraulic cylinder I pushes the top plate and pressure plate I down a certain distance and stops when they are about to contact the coal and rock sample on pressure plate II. The output shaft of hydraulic cylinder II pushes pressure plate II and the coal and rock sample on it upward through the bottom plate. The pressure sensor detects the extrusion force applied by pressure plate II to the coal and rock sample, while the displacement sensor detects the displacement. When the coal and rock sample suffers catastrophic damage or the axial pressure drops sharply, loading stops. The axial pressure is measured by the pressure sensor, and the contact force-displacement curve during the loading process is recorded. Fragments generated during the sample crushing process are collected. S1.2 When dynamic impact is performed, hydraulic cylinder I drives the top plate to rise to different falling heights through the magnetic attraction of the electromagnet to the connecting block to obtain the corresponding impact potential energy. Then the electromagnet is de-energized, releasing the magnetic attraction to the connecting block. The top plate and pressure plate I impact the coal and rock sample downwards under the action of gravity. S1.3 Through the cooperation of T-blocks, T-slots, slots, and rods, as well as the cooperation of positioning slots and positioning pins, it is possible to easily replace pressure plate I and pressure plate II of different shapes to adapt to different crushing modes. Depending on the testing needs, a single toothed pressure plate I can be used to produce splitting crushing, multiple toothed pressure plates I can produce bending crushing, and a flat pressure plate I can produce squeezing crushing, allowing the pressure plates to produce different crushing modes for the sample under test. This allows for testing the stress on coal and rock under different crushing modes. The pressure applying mechanism is connected to the electrical control box, and the control panel of the electrical control box is electrically connected to the pressure applying mechanism. The pressure applying mechanism is started through the control panel, causing pressure plate I to descend and crush the coal and rock sample. S2: Protection and Loading: The control system starts the drive motor, which drives the worm gear to rotate. The worm gear meshes with two worm wheels, driving them to rotate in opposite directions. Meanwhile, the residual gear is not meshed with the rack. The rotation of the rotating shaft causes the two rotating arms to come together, and the two protective half-buckets close to form a protective barrel, protecting the fragmented sample during later experiments. Simultaneously, a high-speed camera (not shown in the diagram) and an acoustic emission monitor (not shown in the diagram) mounted on the top of the workbench are activated to monitor the sample. The control system adjusts the response speed of the protective barrel according to the predicted fragmentation intensity and activates the selected loading module to apply damage to the sample; the fragmented debris is blocked by the protective barrel. S3: Linked cleaning: After the test is completed, the drive motor drives the worm gear, rotating shaft and residual gear to rotate in the opposite direction. The two protective half barrels unfold and reset. At this time, the residual gear meshes with the rack and drives the moving rod and push plate to move towards the pressure plate II. It can discharge the broken coal and rock samples on the pressure plate II onto the annular inclined plate. The slope can guide the debris onto the annular inclined plate. After the push plate finishes discharging the coal and rock sample fragments, the residual gear disengages from the rack and the push plate resets under the tension of the tension spring III. At this time, the protective half barrel and the push plate are in the initial state. S3.1: Because the fixed rod, sliding ring and collar at the top of the base plate are in contact with the bottom of the collar, when the base plate moves the pressure plate II upward for static compression, the base plate pushes the collar and push plate upward, so that the push plate can always discharge the fragments on the pressure plate II; in addition, when the two protective half-buckets are closed for protection, the bottom of the protective half-buckets is in contact with the slope of the base plate. Thus, when the base plate moves upward for static compression, the protective half-buckets move upward synchronously, and the tension spring II is in a stretched state, which can keep the protective half-buckets in a protective state at all times. S4: Debris Recycling: When the drive motor drives the worm gear to rotate in the opposite direction, causing the two protective half-buckets to unfold and the debris on the pressure plate II to be discharged through the push plate, the worm gear drives the fixed shaft to rotate synchronously. The bevel ring drives the one-way bearing to rotate. At this time, the one-way bearing is locked with the bevel gear. The fixed shaft drives the bevel gear to rotate, and the bevel gear drives the rotating ring and Z-shaped plate to rotate through the bevel ring. The Z-shaped plate cooperates with the hemisphere at the top of the annular inclined plate, which can drive the annular inclined plate to vibrate, shaking the debris on it off the annular inclined plate. When the Z-shaped plate rotates, it can push the shaken debris along the annular gap between the rotating ring and the annular inclined plate until it is discharged through the discharge hole and slides into the collection box located below the worktable for easy recycling and analysis.

[0018] Beneficial effects: In this invention, the modular loading mechanism of the device includes a static compression loading module and a dynamic impact loading module, which can flexibly switch loading modes according to different testing requirements. This design can meet the comprehensive testing of the mechanical properties of coal and rock under different loading conditions, providing comprehensive data support for in-depth research on the mechanical properties of coal and rock, and overcoming the limitations of the single loading method of traditional testing devices; In this invention, the two protective half-buckets can effectively prevent fragments from splashing and ensure personnel safety; the rotating ring drives the Z-shaped plate to rotate, which can not only drive the annular inclined plate to vibrate and shake off the fragments on it, but also sweep out the fragments located in the annular gap through the Z-shaped plate, avoiding cross-contamination of different coal and rock samples during the experiment and improving the accuracy of the experiment. In this invention, the protective mechanism and the cleaning mechanism are linked in an original design. The cleaning mechanism can be driven to start the cleaning operation by the two protective half-buckets closing and unfolding and resetting. This realizes the coordinated work of "protection-cleaning", which is fully automated and significantly improves the experimental efficiency. The various mechanisms are well-integrated through mechanical transmission and electrical control. For example, the protective mechanism and the cleaning mechanism are linked through the transmission of components such as worm gears and bevel gears, while the bottom plate lifting and debris cleaning mechanism are linked through components such as fixing rods and collars. This linkage mechanism makes the operation of the device simpler; the entire testing process can be controlled through the control panel, reducing the complexity of operation and the possibility of errors.

[0019] In this invention, the device integrates static extrusion and dynamic impact functions, improving equipment utilization and applicability; the protective half-bucket effectively blocks fragments from splashing, ensuring personnel safety; the rotating ring drives the Z-shaped plate to rotate, which both drives the annular inclined plate to vibrate and shake off fragments, and can also clean up and discharge fragments, avoiding cross-contamination of samples and improving experimental accuracy; the unique protection and cleaning linkage design realizes "protection-cleaning" synergy, fully automating the process and significantly improving experimental efficiency. Attached Figure Description

[0020] Figure 1This is a three-dimensional structural schematic diagram of a mechanical testing device for coal and rock under load provided by the present invention. Figure 2 This is a three-dimensional cross-sectional structural schematic diagram of a mechanical testing device for coal and rock under load provided by the present invention; Figure 3 A three-dimensional exploded structural diagram of the top plate, pressure plate I, and connecting block of a mechanical testing device for coal and rock loading provided by the present invention; Figure 4 This is a partial cross-sectional view of the top plate of a mechanical testing device for coal and rock loading provided by the present invention. Figure 5 A three-dimensional exploded structural diagram of the base plate and pressure plate II of a mechanical testing device for coal and rock loading provided by the present invention; Figure 6 A three-dimensional structural diagram of the protective half-bucket, push plate, and bottom plate of a mechanical testing device for coal and rock loading provided by the present invention. Figure 7 A three-dimensional structural schematic diagram of the protective half-bucket and rotating shaft of a mechanical testing device for coal and rock loading provided by the present invention. Figure 8 A three-dimensional structural schematic diagram of the protective half-bucket and vertical rod of a mechanical testing device for coal and rock loading provided by the present invention; Figure 9 A three-dimensional exploded structural diagram of the worm, rotating ring, and bevel gear ring of a mechanical testing device for coal and rock loading provided by the present invention; Figure 10 A three-dimensional exploded structural diagram of the fixed shaft and bevel gear of a mechanical testing device for coal and rock loading provided by the present invention; Figure 11 A three-dimensional structural schematic diagram of the moving rod, push plate, and rotating shaft of a mechanical testing device for coal and rock loading provided by the present invention; Figure 12 This is a three-dimensional exploded structural diagram of the moving rod, collar, and push plate of a mechanical testing device for coal and rock loading provided by the present invention.

[0021] In the diagram: 1. Workbench; 2. Guide rod; 3. Top seat; 4. Hydraulic cylinder I; 5. Top plate; 6. Connecting block; 7. Pressure sensor; 8. Electromagnet; 9. T-slot; 10. Pressure plate I; 11. T-block; 12. Hydraulic groove I; 13. Piston plate; 14. Locking rod; 15. Tension spring I; 16. Locking groove; 17. Hydraulic groove II; 18. Extrusion block; 19. Base plate; 20. Positioning groove; 21. Pressure plate II; 22. Positioning pin; 23. Coal and rock sample; 24. Hydraulic cylinder II; 25. Displacement sensor; 26. Fixed rod; 27. Sliding rod. 28. Ring; 29. ​​Rotating shaft; 30. Worm gear; 31. Worm; 32. Drive motor; 33. Rotating arm; 34. Protective half-bucket; 35. Vertical rod; 36. Tension spring II; 37. Annular inclined plate; 38. Slope; 39. Discharge hole; 40. Hemisphere; 41. Rotating ring; 42. Annular groove; 43. Bevel ring; 44. Fixed shaft; 45. One-way bearing; 46. Bevel gear; 47. Fixed ring; 48. Z-shaped plate; 49. Collar; 50. Moving rod; 51. Vertical groove; 52. Push plate; 53. Tension spring III; 54. Residual gear; 55. Rack. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0023] In one embodiment: Refer to Figures 1-10 This mechanical testing device relates to the field of coal and rock mechanical property testing technology. It mainly includes a support mechanism, a modular loading mechanism, and a linked protective and cleaning mechanism. Through the coordinated operation of these mechanisms, the device enables mechanical testing of coal and rock samples 23 under different loading modes. Simultaneously, it effectively avoids the splashing of fragments during testing and can automatically clean up fragments, improving the safety and efficiency of the testing.

[0024] Reference Figure 1 and Figure 2The support mechanism, serving as the foundation of the entire device, provides stable support and mounting positions for other mechanisms. Its specific structure is as follows: The workbench 1 is a rectangular flat plate structure made of high-strength steel, possessing sufficient strength and rigidity to withstand various loads during the testing process. Two guide rods 2 are fixed to the top of the workbench 1. The guide rods 2 are cylindrical, made of 45# steel, and chrome-plated to improve wear resistance. The two guide rods 2 are arranged in parallel, with the same top seat 3 fixed to their tops. The top seat 3 is also made of high-strength steel. A hydraulic cylinder I 4 is fixedly inserted through the top seat 3, and an electromagnet 8 is fixed to its output shaft. The electromagnet 8 has a magnetic force range of 500-1000N, sufficient to meet the magnetic attraction requirements with the connecting block 6. A control box is located on the top of the workbench 1, and a control panel is located on one side of the workbench 1. The control box and control panel are electrically connected via wires. The control panel has multiple buttons and a display screen for controlling the operation of the rotating components and the modular loading mechanism, and displaying various parameters during the testing process.

[0025] Reference Figure 1 and Figure 2 The modular loading mechanism is detachably installed on the support mechanism, including a static extrusion loading module and a dynamic impact loading module, which can flexibly switch the loading mode according to the test requirements.

[0026] Reference Figure 2 and Figure 5 The static compression loading module is mainly used to apply static or quasi-static pressure to the coal and rock sample 23. Its structure includes a base plate 19, made of high-strength alloy steel, located on top of the workbench 1. A pressure plate II 21 is located on the top of the base plate 19. A snap-fit ​​structure is provided between the base plate 19 and the pressure plate II 21, including multiple positioning pins 22 and positioning grooves 20. The positioning pins 22 are cylindrical, made of stainless steel, and number 2-6, evenly distributed on the bottom of the pressure plate II 21. The dimensions of the positioning grooves 20 match the positioning pins 22 and are located on the top of the base plate 19. The positioning pins 22 and positioning grooves 20 interlock, allowing the pressure plate II 21 to be stably mounted on top of the base plate 19. The top of the pressure plate II 21 is used to place the coal and rock sample 23, the dimensions of which are determined according to the testing requirements. A hydraulic cylinder II 24 is fixedly inserted through the workbench 1, and its output shaft is fixedly connected to the bottom of the base plate 19. The extension and retraction of hydraulic cylinder II 24 can apply static or quasi-static pressure to the coal and rock sample 23. A displacement sensor 25 is also fixed inside the worktable 1, with its movable end fixedly connected to the bottom of the base plate 19, to detect the displacement distance of the base plate 19, thereby calculating the deformation of the coal and rock sample 23 during the compression process.

[0027] When conducting coal and rock mechanics tests, the loading mode is first selected according to the test requirements. For static compression tests, the coal and rock sample 23 is placed on the pressure plate II 21. The hydraulic cylinder II 24 is extended via the control panel, pushing the base plate 19 and pressure plate II 21 upwards to apply static pressure to the coal and rock sample 23. The displacement sensor 25 detects the displacement distance of the base plate 19 in real time and transmits the data to the control box for processing and display.

[0028] Reference Figure 2 and Figure 3 The dynamic impact loading module is used to apply dynamic impact loads to the coal and rock sample 23. Its structure includes a circular pressure plate I10 made of high-strength alloy steel. The outer walls of the two guide rods 2 are slidably fitted with the same top plate 5, made of aluminum alloy. The pressure plate I10 is positioned at the bottom of the top plate 5 via a connecting structure.

[0029] For dynamic impact testing, the pressure plate I10 is first installed at the bottom of the top plate 5 via a connecting structure. Then, the hydraulic cylinder I4 is extended via the control panel, causing the electromagnet 8 to attract the connecting block 6. The top plate 5 and pressure plate I10 are adjusted to the required height to obtain the corresponding impact potential energy. Afterward, the electromagnet 8 is de-energized, and the top plate 5 and pressure plate I10 fall freely under gravity, applying a dynamic impact load to the coal and rock sample 23. The pressure sensor 7 detects the pressure during the impact process and transmits the data to the control box.

[0030] Reference Figures 2-4 The connecting structure includes two T-shaped grooves 9 at the bottom of the top plate 5, each containing a T-shaped block 11 slidably connected to it. The size of the T-shaped block matches the T-shaped groove 9. Both T-shaped blocks 11 are fixed to the top of the pressure plate I 10. A slot 16 is provided on the side of each T-shaped block 11 that is furthest from each other. The top plate 5 contains two hydraulic grooves I 12. A piston plate 13 is slidably and sealed within each hydraulic groove I 12. The diameter of the piston plate 13 is slightly smaller than the diameter of the hydraulic groove I 12. A locking rod 14 is fixed on the side of each piston plate 13 that is close to each other. The locking rod 14 is cylindrical, and its close-to-each end extends slidably into the corresponding T-shaped groove 9 and engages with the corresponding slot 16 to fix the T-shaped block 11. The outer wall of the lever 14 is fitted with a tension spring I15. The wire diameter of tension spring I15 is 1-2mm, the mean diameter is 8-12mm, the free length is 30-40mm, and the working load range is 50-150N. Its two ends abut against one side of the piston plate 13 and one side of the inner wall of the hydraulic groove I12 through spring seats.

[0031] Depending on the testing requirements, a single toothed pressure plate I10 can be used to generate splitting and fracturing, multiple toothed pressure plates I10 can generate bending and fracturing, and a flat pressure plate I10 can generate compression and fracturing. This allows the pressure plates to produce different fracturing methods for the sample under test, thereby enabling the testing of the stress on coal and rock under different fracturing methods.

[0032] Reference Figure 3 and Figure 4 The top plate 5 has two hydraulic grooves II17, each connected to a corresponding hydraulic groove I12. The hydraulic grooves II17 are located on the piston plate 13 near the T-shaped groove 9. An extrusion block 18 is slidably connected within each hydraulic groove II17. The extrusion block 18 is cylindrical, with a diameter slightly smaller than that of the hydraulic groove II17. A fixing ring 46 is fixedly fitted onto the outer wall of each of the two guide rods 2. The inner diameter of the fixing ring 46 matches the diameter of the guide rod 2, and the fixing ring 46 engages with the extrusion block 18.

[0033] Specifically, when the top plate 5 moves upward, the fixing ring 46 presses the pressing block 18, causing the pressing block 18 to press into the hydraulic groove II 17. The hydraulic oil in the hydraulic groove II 17 enters the hydraulic groove I 12, pushing the piston plate 13 and the locking rod 14 to move, causing the locking rod 14 to disengage from the locking groove 16, thereby disassembling the pressure plate I 10. A magnetic attraction force is generated between the electromagnet 8 and the sheet metal layer installed on the top of the connecting block 6. This magnetic attraction force is greater than the tension of the tension spring I 15 and the sum of the weight of the top plate 5 and the pressure plate I 10, ensuring that the top plate 5 and the pressure plate I 10 can be adjusted to different heights to obtain the corresponding impact potential energy when needed by using the electromagnet 8.

[0034] Reference Figure 1 and Figure 3 A connecting block 6 is fixed to the top of the top plate 5, and a pressure sensor 7 is fixedly embedded in the bottom of the connecting block 6. The pressure sensor 7 has a range of 0-1000kN and an accuracy of 0.1%FS. Its bottom abuts against the top of the top plate 5 and is used to detect pressure during dynamic impact. The control panel is electrically connected to the electromagnet 8, hydraulic cylinder II 24, and hydraulic cylinder I 4, and can control their operation. The pressure sensor 7 and displacement sensor 25 are electrically connected to the control box, transmitting the detected data to the control box for processing and display.

[0035] The interconnected protective and cleaning mechanisms can effectively protect the safety of operators and equipment during testing and automatically clean up debris generated during testing.

[0036] Reference Figure 2 , Figure 6 and Figure 8The protective mechanism includes two protective semi-cylinders 33 and a rotating assembly for driving the two protective semi-cylinders 33 to unfold or close. Two rotating shafts 28 rotate on the top of the workbench 1. The rotating shafts 28 are cylindrical and made of 45# steel. Rotating arms 32 are fixedly fitted onto the outer walls of both rotating shafts 28. The rotating arms 32 are arc-shaped rods. The ends of the two rotating arms 32 that are far apart from each other are slidably connected to the corresponding protective semi-cylinders 33. The protective semi-cylinders 33 are semi-circular and made of high-strength transparent plastic. A vertical rod 34, cylindrical in shape, is fixed to one side of each of the two protective semi-cylinders 33 via a base and slides through the corresponding rotating arm 32. A tension spring II 35 is fitted onto the outer wall of the vertical rod 34. The wire diameter of the tension spring II 35 is 0.8-1.5mm, the mean diameter is 6-10mm, the free length is 100-150mm, and the working load range is 20-80N. Its top and bottom ends are fixedly connected to the outer wall of the vertical rod 34 and the top of the rotating arm 32 respectively through spring seats. The two protective half-buckets 33 are closed to form a protective barrel, which can effectively prevent fragments from scattering after the coal and rock sample 23 is broken.

[0037] Reference Figure 2 and Figure 7 The rotating assembly includes two worm gears 29, which are fixedly sleeved on the outer walls of two rotating shafts 28. A worm 30 located between the two worm gears 29 is rotatably connected to the top of the worktable 1 via a base. The module of the worm 30 matches that of the worm gears 29, and the worm 30 meshes with the two worm gears 29 to drive them to rotate in opposite directions, thereby driving the two protective semi-cylinders 33 to close or open. A drive motor 31 is fixed to the top of the worktable 1 via a frame. The drive motor 31 has a power of 0.5-1kW and a speed of 1000-1500r / min. Its output shaft is fixedly connected to one end of the worm 30 via a coupling. The drive motor 31 is electrically connected to a control panel, which controls the forward and reverse rotation of the drive motor 31 to achieve the opening and closing operations of the protective semi-cylinders 33.

[0038] During the test, the drive motor 31 is controlled to rotate forward via the control panel, which drives the worm gear 30 to rotate. The worm gear 30 drives the two worm wheels 29 to rotate in opposite directions, thereby causing the two protective half-buckets 33 to close together to form a protective barrel, preventing fragments from scattering after the coal and rock sample 23 is broken, and protecting the safety of the operators and surrounding equipment.

[0039] Reference Figure 2 , Figure 5 and Figure 6The cleaning mechanism is located at the support mechanism and includes an annular inclined plate 36 and a rotating ring 40. The annular inclined plate 36 is fixedly mounted on the top of the worktable 1 in a ring shape with the base plate 19 as the center. The top of the annular inclined plate 36 has an inclination angle of 10°-15°. The top of the annular inclined plate 36 is coated with a wear-resistant coating (such as a titanium nitride coating) to reduce sliding wear. Its bottom is fixed to the top of the worktable 1. The top of the annular inclined plate 36 slides in contact with the outer wall of the base plate 19. The top of the base plate 19 has a slope 37 with an inclination angle of 20°-30°, which is used to guide the fragments of the coal and rock sample 23 that fall from the pressure plate II 21 onto the annular inclined plate 36 via the slope 37.

[0040] Reference Figure 2 , Figure 5 and Figure 6 A rotating ring 40 rotates on top of the worktable 1. The inner diameter of the rotating ring 40 is 20-30 mm larger than the outer diameter of the annular inclined plate 36. An annular gap is formed between the rotating ring 40, the annular inclined plate 36, and the worktable 1 to store fragments that roll off the annular inclined plate 36. A discharge hole 38 communicating with the annular gap is provided inside the worktable 1. Multiple Z-shaped plates, 4-6 in number, are fixed to the inner wall of the rotating ring 40 and slide within the annular gap. The bottom of one side of the Z-shaped plate abuts against the top of the annular inclined plate 36, and the Z-shaped plate cooperates with the hemisphere 39. Multiple hemispheres 39 are fixedly arranged in a ring around the base plate 19 on top of the annular inclined plate 36. When the rotating ring 40 drives the Z-shaped plates to rotate, the cooperation between the Z-shaped plates and the hemispheres 39 drives the annular inclined plate 36 to vibrate, shaking off the fragments and discharging them through the discharge hole 38.

[0041] Reference Figure 6 , Figure 9 and Figure 10 The outer wall of the rotating ring 40 is provided with an annular groove 41, and a bevel ring 42 is fixed to the inner top wall of the annular groove 41. One end of the worm gear 30 is fixed with a fixed shaft 43, and a one-way bearing 44 is sleeved on the outer wall of the fixed shaft 43. The inner ring of the one-way bearing 44 is fixed to the outer wall of the fixed shaft 43, and a bevel gear 45 is fixed to the outer ring of the one-way bearing 44. The module of the bevel gear 45 matches that of the bevel ring 42, and the bevel gear 45 meshes with the bevel ring 42. When the fixed shaft 43 reciprocates, the one-way bearing 44 enables the bevel gear 45 to rotate in one direction, thereby driving the rotating ring 40 to rotate in one direction, realizing automatic cleaning of debris.

[0042] After the test, the drive motor 31 is reversed, causing the two protective half-buckets 33 to unfold and reset. During the unfolding and resetting process of the protective half-buckets 33, the worm gear 30 drives the fixed shaft 43 to rotate, which, through the transmission of the one-way bearing 44, bevel gear 45, and bevel ring 42, drives the rotating ring 40 to rotate in one direction. The rotating ring 40 drives the Z-shaped plate to rotate, and the Z-shaped plate cooperates with the hemisphere 39 to vibrate the annular inclined plate 36, shaking the fragments on the annular inclined plate 36 into the annular gap and discharging them through the discharge hole 38, thus achieving automatic cleaning of the fragments.

[0043] In another embodiment: Refer to Figure 3 , Figure 6 , Figure 11 and Figure 12 The structure of this embodiment is basically the same as the previous embodiment, except that: In addition, the outer walls of both rotating shafts 28 are slidably fitted with residual gears 53 via grooves and sliders. A protective box is slidably mounted on the top of the worktable 1 via a slide rod, and is located below the rotating arm 32. Both residual gears 53 rotate within the protective box, and the rotating shafts 28 pass through the protective box. A collar 48 is slidably fitted on the outer wall of one of the guide rods 2, and the inner diameter of the collar 48 matches the diameter of the guide rod 2. A moving rod 49 slides through the collar 48, and the moving rod 49 slides through the protective box. Racks 54 are fixed on both sides of the moving rod 49, and the two racks 54 intermittently mesh with the two residual gears 53 respectively.

[0044] Reference Figure 11 and Figure 12 A push plate 51, which is rectangular, is fixed to one end of the moving rod 49 near the base plate 19. A tension spring III 52 is sleeved on the outer wall of the moving rod 49. The wire diameter of the tension spring III 52 is 1-2 mm, the mean diameter is 8-12 mm, the free length is 80-120 mm, and the working load range is 30-100 N. Its two ends are fixedly connected to the collar 48 and the push plate 51 respectively via spring seats, used to reset the moving rod 49 and the push plate 51. A vertical groove 50 is provided in the guide rod 2 located inside the collar 48 to allow for the raising and lowering of the moving rod 49. A fixing rod 26 is fixed to the outer wall of the base plate 19. A sliding ring 27 is fixed to the top of the fixing rod 26, and the top of the sliding ring 27 abuts against the bottom of the collar 48. This is used to drive the collar 48 to move synchronously when the base plate 19 moves upward for static compression. The sliding ring 27 is slidably sleeved on the outer wall of the corresponding guide rod 2.

[0045] Meanwhile, during the static compression test, when the base plate 19 moves upward, it will drive the collar 48 to move upward synchronously through the fixed rod 26 and the sliding ring 27. The collar 48 drives the moving rod 49 and the push plate 51 to move. The push plate 51 can push the fragments around the base plate 19 onto the annular inclined plate 36, which further facilitates the cleaning of the fragments.

[0046] A testing method for a mechanical testing device for coal and rock under load includes the following steps: S1. Module Installation: According to the test objectives, the static extrusion module and the dynamic impact module are installed on the base plate 19 and the top plate 5. Specifically, the output shaft of hydraulic cylinder I4 moves the top plate 5 upward through the magnetic attraction between the electromagnet 8 and the connecting block 6. The fixing ring 46 extrudes the extrusion block 18, and the extrusion block 18 injects the hydraulic oil in the hydraulic groove II 17 into the hydraulic groove I 12. Under the action of the hydraulic oil, the hydraulic groove I 12 and the clamping rod 14 move away from the T-shaped groove 9, and the clamping groove 16 disengages from the T-shaped groove 9. Then, the pressure plate I... The two T-shaped blocks 11 at the top of the 10 slide into the corresponding T-shaped grooves 9. The output shaft of the hydraulic cylinder I4 pushes the top plate 5 down, the collar 48 loses the squeezing force of the fixing ring 46, the piston plate 13 resets under the tension of the tension spring I15, and the locking rod 14 extends into the locking groove 16 to fix the T-shaped blocks 11. Then, the multiple positioning pins 22 at the bottom of the pressure plate II21 are aligned with the positioning grooves 20 and inserted to complete the installation of the base plate 19 and the pressure plate II21. In addition, the static extrusion module or the dynamic impact module can be switched as needed. S1.1 During static extrusion, the output shaft of hydraulic cylinder I4 pushes the top plate 5 and pressure plate I10 down a certain distance and stops when they are about to contact the coal and rock sample 23 on pressure plate II21. The output shaft of hydraulic cylinder II24 pushes pressure plate II21 and the coal and rock sample 23 on it upward through the bottom plate 19. The pressure sensor 7 detects the extrusion force applied by pressure plate II21 to coal and rock sample 23, while the displacement sensor 25 can detect the displacement. When coal and rock sample 23 is catastrophically damaged or the axial pressure drops sharply, loading stops. The axial pressure is measured by pressure sensor 7, and the contact force-displacement curve during the loading process is recorded. The fragments generated during the sample crushing process are collected. S1.2 When dynamic impact is performed, the hydraulic cylinder I4 drives the top plate 5 to rise to different falling heights through the magnetic attraction of the electromagnet 8 to the connecting block 6 to obtain the corresponding impact potential energy. Then the electromagnet 8 is de-energized, releasing the magnetic attraction of the connecting block 6. The top plate 5 and the pressure plate I10 impact the coal and rock sample 23 downward under the action of gravity. S1.3 The T-shaped block 11, T-shaped groove 9, slot 16 and locking rod 14, as well as the positioning groove 20 and positioning pin 22, can easily replace pressure plates I 10 and II 21 of different shapes to adapt to different crushing modes. According to the test requirements, a single toothed pressure plate I 10 can be replaced to produce splitting crushing, multiple toothed pressure plates I 10 can produce bending crushing, and a flat pressure plate I 10 can produce extrusion crushing, so that the pressure plates produce different crushing modes for the sample to be tested. Thus, the stress of coal and rock under different crushing modes can be tested. The pressure mechanism is connected to the electrical control box, and the control panel of the electrical control box is electrically connected to the pressure mechanism. The pressure mechanism is started through the control panel, which drives the pressure plate I 10 to descend and crush the coal and rock sample 23. S2: Protection and Loading: The control system starts the drive motor 31, which drives the worm 30 to rotate. The worm 30 meshes with two worm wheels 29, driving them to rotate in opposite directions. Meanwhile, the residual gear 53 is not meshed with the rack 54. The rotation of the rotating shaft 28 causes the two rotating arms 32 to come closer together. The two protective half-buckets 33 close together to form a protective barrel, which protects the fragmented sample during later experiments. At the same time, the high-speed camera (not shown in the figure) and acoustic emission monitor (not shown in the figure) installed on the top of the workbench 1 are activated to monitor the sample. The control system can adjust the response speed of the protective barrel according to the predicted fragmentation intensity and activate the selected loading module to apply damage to the sample. The fragments are blocked by the protective barrel. S3: Linked cleaning: After the test is completed, the drive motor 31 drives the worm gear 30, the rotating shaft 28, and the residual gear 53 to rotate in the opposite direction. The two protective half-buckets 33 unfold and reset. At this time, the residual gear 53 meshes with the rack 54 and drives the moving rod 49 and the push plate 51 to move towards the pressure plate II 21. It can discharge the broken coal and rock sample 23 on the pressure plate II 21 onto the annular inclined plate 36, and the slope 37 can guide the debris onto the annular inclined plate 36. After the push plate 51 finishes discharging the broken pieces of coal and rock sample 23, the residual gear 53 disengages from the rack 54, and the push plate 51 resets under the tension of the tension spring III 52. At this time, the protective half-bucket 33 and the push plate 51 are in the initial state. S3.1: Since the fixed rod 26 and sliding ring 27 at the top of the base plate 19 abut against the bottom of the collar 48, when the base plate 19 drives the pressure plate II 21 to move upward for static compression, the base plate 19 pushes the collar 48 and push plate 51 upward, so that the push plate 51 can always discharge the fragments located on the pressure plate II 21; in addition, when the two protective half barrels 33 are closed for protection, the bottom of the protective half barrel 33 abuts against the slope 37 on the base plate 19. Thus, when the base plate 19 moves upward for static compression, the protective half barrel 33 moves upward synchronously, and the tension spring II 35 is in a stretched state, so that the protective half barrel 33 can always be in a protective state. S4: Debris Recycling: When the drive motor 31 drives the worm gear 30 to rotate in the opposite direction, causing the two protective half-buckets 33 to unfold and the debris on the pressure plate II 21 to be discharged through the push plate 51, the worm gear 30 drives the fixed shaft 43 to rotate synchronously, and the bevel ring 42 drives the one-way bearing 44 to rotate. At this time, the one-way bearing 44 is locked with the bevel gear 45. The fixed shaft 43 drives the bevel gear 45 to rotate, and the bevel gear 45 drives the rotating ring 40 and the Z-shaped plate 47 to rotate through the bevel ring 42. The Z-shaped plate 47 cooperates with the hemisphere 39 at the top of the annular inclined plate 36, which can drive the annular inclined plate 36 to vibrate, shaking the debris on it off the annular inclined plate 36. When the Z-shaped plate 47 rotates, it can push the shaken debris along the annular gap between the rotating ring 40 and the annular inclined plate 36 until it is discharged through the discharge hole 38 and slides into the collection box located below the workbench 1 for easy recycling and analysis.

[0047] However, as is well known to those skilled in the art, the working principles and wiring methods of the drive motor 31, hydraulic cylinder II 24, displacement sensor 25, electromagnet 8, pressure sensor 7 and hydraulic cylinder I 4 are commonplace and belong to conventional means or common knowledge. They will not be described in detail here. Those skilled in the art can make any selections according to their needs or convenience.

[0048] The accompanying drawings in this application are for illustrative purposes only. The dimensions and shapes of the components shown are not actual limitations but are merely schematic representations. In actual implementation, the components can be reasonably configured and adjusted according to specific needs and actual conditions.

[0049] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A mechanical testing device for coal and rock under load, characterized in that, Including supporting institutions; It also includes a modular loading mechanism, which is detachably mounted on the support mechanism for applying loads to the coal and rock sample (23) within the support mechanism; It also includes a linkage protection mechanism and a cleaning mechanism, wherein: the protection mechanism includes two protective half barrels (33) and a rotating component for driving the two protective half barrels (33) to open or close, the two protective half barrels (33) close to avoid the fragments of the coal and rock sample (23) from being scattered after being broken; The cleaning mechanism is located at the support mechanism and includes an annular inclined plate (36) and a rotating ring (40); the cleaning mechanism can be driven when the two protective half-buckets (33) are unfolded and reset.

2. The mechanical testing device for coal and rock under load according to claim 1, characterized in that, The support mechanism includes a workbench (1), with two guide rods (2) fixed on the top of the workbench (1). The top ends of the two guide rods (2) are fixed with the same top seat (3). A hydraulic cylinder I (4) is fixedly inserted inside the top seat (3). An electromagnet (8) is fixed to the output shaft of the hydraulic cylinder I (4). A control box is provided on the top of the workbench (1), and a control panel is provided on one side of the workbench (1). The control box is electrically connected to the control panel. The control panel is used to control the rotating components and the modular loading mechanism.

3. The mechanical testing device for coal and rock under load according to claim 2, characterized in that, The modular loading mechanism includes a static extrusion loading module and a dynamic impact loading module; The static extrusion loading module includes a base plate (19) set on the top of the workbench (1). The top of the base plate (19) is provided with a pressure plate II (21). A snap-fit ​​structure is provided between the base plate (19) and the pressure plate II (21) for the pressure plate II (21) to be stably installed on the top of the base plate (19). The top of the pressure plate II (21) is used to place a coal and rock sample (23). A hydraulic cylinder II (24) is fixedly inserted through the workbench (1). The output shaft of the hydraulic cylinder II (24) is fixedly connected to the bottom of the base plate (19) for applying static or quasi-static pressure to the coal and rock sample (23). A displacement sensor (25) is fixedly inserted inside the workbench (1). The movable end of the displacement sensor (25) is fixedly connected to the bottom of the base plate (19) for detecting the displacement distance of the base plate (19). The dynamic impact loading module includes a pressure plate I (10), and the outer walls of the two guide rods (2) are slidably fitted with the same top plate (5). The pressure plate I (10) is set at the bottom of the top plate (5) through a connecting structure. A connecting block (6) is fixed at the top of the top plate (5). A pressure sensor (7) is fixedly embedded at the bottom of the connecting block (6), and the bottom of the pressure sensor (7) abuts against the top of the top plate (5). A magnetic attraction is generated between the electromagnet (8) and the iron sheet layer installed at the top of the connecting block (6). The hydraulic cylinder I (4) can adjust the top plate (5) and the pressure plate I (10) to different heights to obtain the corresponding impact potential energy through the magnetic attraction between the electromagnet (8) and the connecting block (6).

4. The mechanical testing device for coal and rock under load according to claim 3, characterized in that, The snap-fit ​​structure includes multiple positioning pins (22) and positioning grooves (20). The multiple positioning pins (22) are fixed at the bottom of the pressure plate II (21), and the multiple positioning grooves (20) are set at the top of the base plate (19). The positioning pins (22) and positioning grooves (20) are inserted into each other.

5. A mechanical testing device for coal and rock under load according to claim 4, characterized in that, The connection structure includes two T-shaped grooves (9) at the bottom of the top plate (5), and T-shaped blocks (11) are slidably connected in both T-shaped grooves (9). Both T-shaped blocks (11) are fixed to the top of the pressure plate I (10). The two T-shaped blocks (11) are provided with slots (16) on the side away from each other. The top plate (5) is provided with two hydraulic grooves I (12). Both hydraulic grooves I (12) are sealed and slidably connected with piston plates (13). Both piston plates (13) are fixed with locking rods (14) on the side close to each other. The ends of the two locking rods (14) are sealed and slidably extended into the corresponding T-shaped grooves (9) and inserted into the corresponding slots (16) to fix the T-shaped blocks (11). The outer wall of the locking rods (14) is fitted with tension springs I (15). The two ends of the tension springs I (15) are connected by springs. The seat abuts against one side of the piston plate (13) and the inner wall of one side of the hydraulic groove I (12). The top plate (5) is provided with two hydraulic grooves II (17). The two hydraulic grooves II (17) are connected to the corresponding hydraulic groove I (12). The hydraulic grooves II (17) are located on the side of the piston plate (13) near the T-shaped groove (9). The hydraulic grooves II (17) are sealed and slidably connected with a pressing block (18). The outer walls of the two guide rods (2) are fixedly fitted with fixing rings (46), and the fixing rings (46) cooperate with the pressing block (18) to press the pressing block (18) into the hydraulic groove II (17) and make the clamping rod (14) disengage from the clamping groove (16) when the top plate (5) moves up. The magnetic attraction between the electromagnet (8) and the connecting block (6) is greater than the tension of the tension spring I (15) and the sum of the weight of the top plate (5) and the pressure plate I (10).

6. A mechanical testing device for coal and rock under load according to claim 5, characterized in that, The protective mechanism also includes two rotating shafts (28) rotating on the top of the workbench (1). The outer walls of the two rotating shafts (28) are fixedly fitted with rotating arms (32). The ends of the two rotating arms (32) that are far apart from each other are slidably connected to the corresponding protective half-barrels (33). One side of each of the two protective half-barrels (33) is fixed with a vertical rod (34) through a base. The vertical rod (34) slides through the corresponding rotating arm (32). The outer wall of the vertical rod (34) is fitted with a tension spring II (35). The top and bottom ends of the tension spring II (35) are fixedly connected to the outer wall of the vertical rod (34) and the top of the rotating arm (32) respectively through spring seats. The two protective half-barrels (33) are closed to form a protective barrel body.

7. A mechanical testing device for coal and rock under load according to claim 6, characterized in that, The rotating assembly includes two worm gears (29), which are respectively fixedly sleeved on the outer walls of two rotating shafts (28). The top of the workbench (1) is rotatably connected to a worm (30) located between the two worm gears (29) via a base. The worm (30) meshes with the two worm gears (29) to drive the two worm gears (29) to rotate in opposite directions, thereby driving the two protective half-barrels (33) to close or unfold. The top of the workbench (1) is fixed with a drive motor (31) via a frame. The output shaft of the drive motor (31) is fixedly connected to one end of the worm (30) via a coupling. The drive motor (31) is electrically connected to the control panel.

8. A mechanical testing device for coal and rock under load according to claim 7, characterized in that, The cleaning mechanism also includes multiple hemispheres (39), which are fixedly arranged in a ring around the base plate (19) on the top of the annular inclined plate (36). The bottom of the annular inclined plate (36) is fixed to the top of the worktable (1). The top of the annular inclined plate (36) slides in conjunction with the outer wall of the base plate (19). The rotating ring (40) rotates on the top of the worktable (1). An annular gap is formed between the rotating ring (40), the annular inclined plate (36), and the worktable (1) for storing waste rings. The fragments rolling off the inclined plate (36) are distributed by a plurality of Z-shaped plates (47) fixed to the inner wall of the rotating ring (40) and sliding within the annular gap. The worktable (1) is provided with a discharge hole (38) communicating with the annular gap. The rotating ring (40) drives the Z-shaped plates (47) to rotate, which can discharge the fragments in the annular gap through the discharge hole (38). The bottom side of one side of the Z-shaped plate (47) abuts against the top of the annular inclined plate (36). The Z-shaped plate (47) cooperates with the hemisphere (39) for use in the rotating ring (40). When the Z-shaped plate (47) rotates, the Z-shaped plate (47) and the hemisphere (39) drive the annular inclined plate (36) to vibrate, causing the fragments on it to fall off. The top of the bottom plate (19) is provided with a slope (37) to guide the fragments of the coal and rock sample (23) to the annular inclined plate (36) after they fall from the pressure plate II (21). The outer wall of the rotating ring (40) is provided with an annular groove (41), and the inner wall of the top of the annular groove (41) is fixed with a beveled tooth ring (42). The worm gear (3 One end of the fixed shaft (43) is fixed, and a one-way bearing (44) is sleeved on the outer wall of the fixed shaft (43). The inner ring of the one-way bearing (44) is fixed on the outer wall of the fixed shaft (43). A bevel gear (45) is fixed on the outer ring of the one-way bearing (44), and the bevel gear (45) meshes with the bevel ring (42). When the fixed shaft (43) reciprocates, the bevel gear (45) can rotate in one direction through the setting of the one-way bearing (44), thereby driving the rotating ring (40) to rotate in one direction.

9. A mechanical testing device for coal and rock under load according to claim 8, characterized in that, The outer walls of both rotating shafts (28) are fitted with residual gears (53) via grooves and sliders. The top of the workbench (1) is fitted with a protective box via a sliding rod and is located below the rotating arm (32). Both residual gears (53) rotate within the protective box. The rotating shafts (28) pass through the protective box. A collar (48) is fitted on the outer wall of one of the guide rods (2). A moving rod (49) slides through the collar (48). The moving rod (49) slides through the protective box. Racks (54) are fixed on both sides of the moving rod (49). The two racks (54) intermittently mesh with the two residual gears (53). A push plate (51) is fixed at one end of the moving rod (49) near the bottom plate (19). The outer wall of the moving rod (49) is fitted with a tension spring III (52). The two ends of the tension spring III (52) are fixedly connected to the collar (48) and the push plate (51) respectively through spring seats, which is used to reset the moving rod (49) and the push plate (51). The guide rod (2) located in the collar (48) is provided with a vertical groove (50), which is used to make way for the moving rod (49) to rise and fall. The outer wall of the base plate (19) is fixed with a fixing rod (26). The top of the fixing rod (26) is fixed with a sliding ring (27), and the top of the sliding ring (27) abuts against the bottom of the collar (48), which is used to drive the collar (48) to move synchronously when the base plate (19) moves up for static compression. The sliding ring (27) is slidably fitted on the outer wall of the corresponding guide rod (2).

10. A testing method for a mechanical testing device for coal and rock under load, applied to the mechanical testing device for coal and rock under load as described in claim 9, characterized in that, Includes the following steps: S1. Module Installation: According to the test objective, the static extrusion module and the dynamic impact module are installed on the base plate (19) and the top plate (5). Specifically, the output shaft of the hydraulic cylinder I (4) drives the top plate (5) to move upward through the magnetic attraction of the electromagnet (8) and the connecting block (6). The fixing ring (46) extrudes the extrusion block (18), and the extrusion block (18) injects the hydraulic oil in the hydraulic groove II (17) into the hydraulic groove I (12). The hydraulic groove I (12) and the clamping rod (14) move away from the T-groove (9) under the action of the hydraulic oil. The clamping groove (16) disengages from the T-groove (9). Then, the pressure plate I ( 10) The two T-shaped blocks (11) at the top slide into the corresponding T-shaped grooves (9), the output shaft of hydraulic cylinder I (4) pushes the top plate (5) down, the collar (48) loses the squeezing force of the fixing ring (46), the piston plate (13) resets under the tension of tension spring I (15), the locking rod (14) extends into the locking groove (16) to complete the fixing of the T-shaped block (11), then the multiple positioning pins (22) at the bottom of the pressure plate II (21) are aligned with the positioning groove (20) and inserted to complete the installation of the base plate (19) and the pressure plate II (21); in addition, the static extrusion module or the dynamic impact module can be switched as needed; S1.1 When static extrusion is performed, the output shaft of hydraulic cylinder I (4) pushes the top plate (5) and pressure plate I (10) down a certain distance and stops running when they are about to contact the coal and rock sample (23) on pressure plate II (21). The output shaft of hydraulic cylinder II (24) pushes pressure plate II (21) and the coal and rock sample (23) on it to move upward through the bottom plate (19). The pressure sensor (7) detects the extrusion force applied by pressure plate II (21) to coal and rock sample (23), while the displacement sensor (25) can detect the displacement. When the coal and rock sample (23) suffers catastrophic damage or the axial pressure drops sharply, the loading stops. The axial pressure is measured by the pressure sensor (7), and the contact force-displacement curve during the loading process is recorded. The fragments generated during the sample crushing process are collected. S1.2 When dynamic impact is performed, the hydraulic cylinder I (4) drives the top plate (5) to rise to different falling heights through the magnetic attraction of the electromagnet (8) to the connecting block (6) to obtain the corresponding impact potential energy. Then the electromagnet (8) is de-energized, releasing the magnetic attraction of the connecting block (6). The top plate (5) and the pressure plate I (10) impact the coal and rock sample (23) downward under the action of gravity. S1.3, Through the cooperation of T-block (11), T-slot (9), slot (16) and lever (14) and the cooperation of positioning slot (20) and positioning pin (22), it is possible to easily replace pressure plate I (10) and pressure plate II (21) of different shapes to adapt to different destruction modes. According to the test requirements, a single toothed pressure plate I (10) can be replaced to produce splitting and crushing, multiple toothed pressure plates I (10) can produce bending and crushing, and flat pressure plate I (10) can produce squeezing and crushing, so that the pressure plate produces different crushing modes for the sample to be tested, thereby testing the stress of coal and rock under different crushing modes. The pressure mechanism is connected to the electrical control box, and the control panel of the electrical control box is electrically connected to the pressure mechanism. The pressure mechanism is started through the control panel, which drives the pressure plate I (10) to descend and destroy the coal and rock sample (23). S2: Protection and Loading: The drive motor (31) is started by the control system. The drive motor (31) drives the worm (30) to rotate. The worm (30) meshes with the two worm wheels (29) and drives the two worm wheels (29) to rotate. The two worm wheels (29) rotate in opposite directions. At this time, the residual gear (53) is not meshed with the rack (54). The rotation of the rotating shaft (28) can make the two rotating arms (32) come closer to each other. After the two protective half-buckets (33) are closed, they form a protective bucket body, which protects the splattered sample in the later experiment. At the same time, the high-speed camera and acoustic emission monitor installed on the top of the workbench (1) are started to monitor. The control system can adjust the response speed of the protective bucket according to the predicted fragmentation intensity and start the selected loading module to apply damage to the sample. The fragments are blocked by the protective bucket. S3: Linkage cleaning: After the test is completed, the drive motor (31) drives the worm (30) and the rotating shaft (28) and the residual gear (53) to rotate in the opposite direction. The two protective half barrels (33) unfold and reset. At this time, the residual gear (53) meshes with the rack (54) and drives the moving rod (49) and the push plate (51) to move towards the pressure plate II (21). It can discharge the broken coal and rock sample (23) on the pressure plate II (21) onto the annular inclined plate (36). The slope (37) can guide the debris onto the annular inclined plate (36). When the push plate (51) finishes discharging the coal and rock sample (23) fragments, the residual gear (53) disengages from the rack (54). The push plate (51) resets under the tension of the tension spring III (52). At this time, the protective half barrel (33) and the push plate (51) are in the initial state. S3.1: Since the bottom of the fixed rod (26), sliding ring (27) and collar (48) at the top of the base plate (19) is in contact, when the base plate (19) drives the pressure plate II (21) to move upward for static compression, the base plate (19) pushes the collar (48) and push plate (51) to move upward, so that the push plate (51) can always discharge the fragments on the pressure plate II (21); in addition, when the two protective half barrels (33) are closed for protection, the bottom of the protective half barrel (33) is in contact with the slope (37) on the base plate (19). Thus, when the base plate (19) moves upward for static compression, the protective half barrel (33) moves upward synchronously, and the tension spring II (35) is in a stretched state, so that the protective half barrel (33) is always in a protective state. S4: Debris Recycling: When the drive motor (31) drives the worm gear (30) to rotate in the opposite direction, causing the two protective half-buckets (33) to unfold and discharge the debris on the pressure plate II (21) through the push plate (51), the worm gear (30) drives the fixed shaft (43) to rotate synchronously, and the bevel ring (42) drives the one-way bearing (44) to rotate. At this time, the one-way bearing (44) is locked with the bevel gear (45). The fixed shaft (43) drives the bevel gear (45) to rotate, and the bevel gear (45) drives the bevel ring (42) to rotate. The rotating ring (40) and the Z-shaped plate (47) rotate. The Z-shaped plate (47) cooperates with the hemisphere (39) at the top of the annular inclined plate (36) to drive the annular inclined plate (36) to vibrate, causing the fragments on it to fall off the annular inclined plate (36). When the Z-shaped plate (47) rotates, it can push the fallen fragments along the annular gap between the rotating ring (40) and the annular inclined plate (36) until they are discharged through the discharge hole (38) and slide into the collection frame located below the workbench (1) for easy recycling and analysis.

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