Automatic Rock Positioning and Fragment Screening Method Applicable to Split Hopkinson Pressure Bar

Abstract

The present invention discloses a method for automatic positioning and fragment screening of rocks applicable to a Hopkinson bar, comprising the following steps: S1: Using a specimen positioning device to accurately position and impact-crush the specimen; the specimen positioning device includes a hollow housing, and mounting through-holes matching the incident bar and the transmission bar are respectively formed on the front and rear sides of the housing; an electromagnetic impact device and an arm for clamping the specimen are provided inside the housing, the electromagnetic impact device is located on the left side wall or the rear side wall of the housing, the arm is rotatably arranged between the front and rear side walls of the housing, and the end of the arm close to the specimen is located below the electromagnetic impact device; S2: Automatically collecting the fragments after crushing the specimen into an automatic screening device for screening, and the automatic screening device is located below the specimen positioning device. The present invention can not only improve the accuracy and scientificity of the test of the dynamic mechanical properties of the specimen under the action of impact load, but also avoid the potential threat caused by the high-speed splashing of the fragments.

Description

Technical Field

[0001] The present invention relates to a dynamic impact mechanics experimental test method for rock-like materials, and particularly to an automatic positioning and fragment screening method for rocks applicable to a Hopkinson pressure bar. Background Art

[0002] Exploring the dynamic impact mechanical response of rocks has always been an important direction in the field of rock dynamics. Among them, after decades of development, the split Hopkinson pressure bar device has been widely used in the test of the dynamic mechanical properties of various materials under impact loads. However, in the traditional split Hopkinson pressure bar test for rocks, there are the following several typical problems that directly affect the accuracy and effectiveness of the test: (1) How to accurately co-align a cylindrical rock specimen with an incident bar, a transmission bar, etc.; (2) How to ensure the one-dimensional stress state of the specimen during the impact loading process; (3) The distribution law of the fragments of the rock after impact compression and fragmentation is crucial for studying the impact mechanical properties of rocks and is a key index directly reflecting the degree of rock fragmentation. However, the fragments of the rock after impact fragmentation are easily splashed and lost, and there is no effective solution to how to completely collect the fragmented pieces for screening tests. Summary of the Invention

[0003] Aiming at the above existing problems, the present invention aims to provide an automatic positioning and fragment screening method for rocks of a Hopkinson pressure bar, which can not only achieve precise positioning among a rock specimen, an incident bar, and a transmission bar, but also achieve a one-dimensional stress state during the impact compression loading process of the specimen, and solve the problem of difficult collection of the fragments after impact compression and fragmentation; it improves the accuracy and scientific nature of the test, and greatly increases the safety of the instruments and equipment and the operators in the test, avoiding potential threats caused by the high-speed splashing of fragments.

[0004] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0005] An automatic positioning and fragment screening method for rocks applicable to a Hopkinson pressure bar, characterized by including the following steps,

[0006] S1: Using a specimen positioning device to accurately position and impact-fragment a specimen;

[0007] Wherein, the specimen positioning device includes a hollow housing, and through holes matching the incident bar and the transmission bar are respectively opened on the front and rear sides of the housing; an electromagnetic impact device and an arm for clamping the specimen are provided inside the housing, the electromagnetic impact device is located on the left side wall or the rear side wall of the housing, the arm is rotatably arranged between the front and rear side walls of the housing, and the end of the arm close to the specimen is located below the electromagnetic impact device;

[0008] S2: Automatically collect the fragments after the specimen is broken into an automatic screening device for screening. The automatic screening device is located below the specimen positioning device.

[0009] Further, the specific operations of step S1 include the following steps:

[0010] S101: Use the protective arm to clamp and fix the specimen, and make the protective arm swing freely in the housing.

[0011] S102: When the protective arm rotates to align the specimen with the incident rod and the transmission rod, use the electromagnetic impact device to strike the protective arm to release the specimen from the protective arm.

[0012] S103: While the protective arm releases the specimen, use the incident rod to strike the specimen to break it.

[0013] Further, the electromagnetic impact device includes a mounting shell. A first mounting groove is opened at the bottom of the mounting shell, and an electromagnet is provided at the top of the first mounting groove. A hammer made of metal is provided in the first mounting groove. A plurality of groups of first springs are fixedly provided at the top of the hammer, and the ends of the first springs away from the hammer are fixedly connected to the top of the first mounting groove.

[0014] Further, the protective arm includes a swing rod and a clamping component for clamping the specimen. A mounting shaft is fixedly provided between the front and rear side walls of the housing. A rotating hole is opened at one end of the swing rod away from the clamping component. The mounting shaft passes through the rotating hole, and the swing rod is rotationally connected to the mounting shaft through the rotating hole.

[0015] Further, the clamping component includes an upper semi-circular clamping ring and a lower semi-circular clamping ring. One end of the lower semi-circular clamping ring corresponding to the upper semi-circular clamping ring is movably connected by a tenon and a buckle. The other ends of the lower semi-circular clamping ring and the upper semi-circular clamping ring corresponding to each other are respectively provided with a first connecting arm and a second connecting arm. The first connecting arm and the second connecting arm are rotationally connected, and an adsorption magnet is fixedly provided at one end of the first connecting arm away from the lower semi-circular clamping ring. The end of the adsorption magnet away from the first connecting arm is fixedly connected to the swing rod.

[0016] Further, two connecting columns are provided at one end of the lower semi-circular clamping ring close to the first connecting arm. A second mounting groove is opened on each connecting column. A second spring is installed in the second mounting groove. A short column is fixedly provided at the free end of the second spring. The short column passes through the second mounting groove. Two connecting plates matching the short column are fixedly provided at one end of the upper semi-circular clamping ring close to the second connecting arm.

[0017] Further, a discharge port is opened at the bottom of the housing. The automatic screening device is located below the discharge port.

[0018] The automatic screening device includes an installation frame, which is of an L-shaped structure. Sliding through holes are symmetrically formed on the front side wall and the rear side wall of the installation frame. A hydraulic rod is installed on the inner side wall of one end of the installation frame away from the vertical section. The output end of the hydraulic rod is connected to a screening component. Positioning pins are fixedly provided on the front side and the rear side of the screening component. The positioning pins penetrate through the corresponding sliding through holes, and a limiting plate is fixedly provided at one end of the positioning pin located outside the installation frame.

[0019] Furthermore, the screening component includes a housing. A first cover plate is detachably provided at the top of the housing. The center of the first cover plate is of an opening structure, and a second cover plate is detachably connected to the center opening of the first cover plate. Inside the housing, a first screen, a second screen, and a third screen are sequentially sleeved from the inside to the outside. The second cover plate is matched with the first screen. A driving component for simultaneously driving the first screen, the second screen, and the third screen to rotate is provided at the bottom of the housing.

[0020] Furthermore, the driving component includes a driving motor. A first rotating shaft is connected to the output shaft of the driving motor. A first gear, a second gear, and a third gear are sequentially and fixedly sleeved on the first rotating shaft from top to bottom. The outer diameter of the second gear is different from the outer diameters of the first gear and the third gear.

[0021] A second rotating shaft is fixedly provided at the bottom of the third screen. A third rotating shaft is fixedly provided at the bottom of the second screen. The third rotating shaft is sleeved inside the second rotating shaft, and the bottom end of the third rotating shaft is located outside the second rotating shaft. A fourth rotating shaft is fixedly provided at the bottom of the first screen. The fourth rotating shaft is sleeved inside the third rotating shaft, and the bottom of the fourth rotating shaft is located outside the third rotating shaft. A fourth gear is fixedly sleeved outside the second rotating shaft. A fifth gear is fixedly sleeved on the part of the third rotating shaft located outside the second rotating shaft. A sixth gear is fixedly sleeved on the part of the fourth rotating shaft located outside the third rotating shaft. The fourth gear meshes with the first gear. The fifth gear meshes with the second gear. The sixth gear meshes with the third gear.

[0022] Furthermore, a protection cylinder is fixedly provided at the bottom of the housing. The first gear, the second gear, the third gear, the fourth gear, the fifth gear, and the sixth gear are all located inside the protection cylinder. A third cover plate is provided at the bottom of the protection cylinder. The first rotating shaft penetrates through the third cover plate. The output end of the hydraulic rod is connected to the bottom of the cover plate.

[0023] The beneficial effects of the present invention are: Compared with the prior art, the improvements of the present invention lie in

[0024] 1. In the present invention, the automatic rock positioning and fragment screening method applicable to the Hopkinson bar can not only achieve precise positioning among the rock specimen, the incident bar, and the transmission bar through the mutual cooperation of the swing of the protective arm and the laser emission device, but also the protective arm disengages from the specimen during the specimen impact process, avoiding the influence of the confining pressure of the protective arm on the experimental results, thereby realizing the one-dimensional stress state during the specimen impact compression loading process; in addition, the present invention also solves the problem of difficult collection of impact compression broken fragments; it improves the accuracy and scientific nature of the test, greatly increases the safety of the instruments and equipment and the operators in the test, and avoids the potential threat caused by the high-speed splashing of fragments.

[0025] 2. In the specimen positioning device of the present invention, the protective arm can swing freely around the mounting shaft without external power drive. The housing can not only serve as the mounting basis for other components, but also prevent the fragments after specimen crushing from flying out. The fragments after specimen crushing can be collected through the discharge port at the bottom of the housing and then screened; the upper semi-circular clamp ring and the lower semi-circular clamp ring in the protective arm structure can be automatically separated under the action of the electromagnetic impact device.

[0026] 3. The automatic screening device in the present invention drives the gear set to rotate through the driving motor, so as to drive the first screen, the second screen, and the third screen to rotate at different speeds, improving the screening efficiency while realizing automatic screening. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the external structure of the specimen positioning device in Embodiment 1 of the present invention.

[0028] Figure 2 It is an axonometric drawing of the internal structure of the specimen positioning device in Embodiment 1 of the present invention.

[0029] Figure 3 It is a sectional view of the internal structure of the specimen positioning device in Embodiment 1 of the present invention.

[0030] Figure 4 It is a schematic diagram of the installation position of the laser emission device in Embodiment 1 of the present invention.

[0031] Figure 5 It is a schematic diagram of the structure of the electromagnetic impact device in Embodiment 1 of the present invention.

[0032] Figure 6 It is an axonometric drawing of the protective arm structure in Embodiment 1 of the present invention.

[0033] Figure 7 It is an exploded view of the protective arm structure in Embodiment 1 of the present invention.

[0034] Figure 8 It is a schematic diagram of the structure of the upper semi-circular clamp ring in Embodiment 1 of the present invention.

[0035] Figure 9 This is a schematic diagram of the lower semi-circular clamping ring structure in the first embodiment of the present invention.

[0036] Figure 10 This is a schematic diagram of the overall structure of the sample positioning device and the automatic screening device in the second embodiment of the present invention.

[0037] Figure 11 This is an axonometric view of the structure of the automatic screening device in the second embodiment of the present invention.

[0038] Figure 12 This is an exploded view of the structure of the automatic screening device in the second embodiment of the present invention.

[0039] Figure 13 This is a sectional view of the structures of the first screen, the second screen, and the third screen in the second embodiment of the present invention.

[0040] Figure 14 This is a bottom view of the structure of the screening assembly in the second embodiment of the present invention.

[0041] Figure 15 This is a schematic diagram of the positional relationship among the first screen, the second screen, and the third screen in the second embodiment of the present invention.

[0042] Figure 16 This is a schematic diagram of the structure of the drive assembly in the second embodiment of the present invention.

[0043] Wherein: 1 - housing, 101 - discharge port, 2 - support leg, 3 - incident rod, 4 - transmission rod, 5 - mounting through hole, 6 - electromagnetic impact device, 601 - mounting shell, 602 - first mounting groove, 603 - hammer, 604 - first spring, 7 - protective arm, 701 - swing rod, 702 - rotation hole, 703 - upper semi-circular clamping ring, 7031 - connecting plate, 704 - lower semi-circular clamping ring, 7041 - connecting column, 7042 - second mounting groove, 7043 - second spring, 7044 - short column, 705 - tenon, 706 - buckle, 707 - first connecting arm, 708 - second connecting arm, 709 - adsorption magnet, 8 - laser emission device, 9 - mounting shaft, 10 - mounting frame, 11 - sliding through hole, 12 - hydraulic rod, 13 - positioning pin, 14 - limiting plate, 15 - outer shell, 16 - first cover plate, 17 - second cover plate, 18 - first screen, 19 - second screen, 20 - third screen, 21 - drive motor, 22 - first rotating shaft, 23 - first gear, 24 - second gear, 25 - third gear, 26 - second rotating shaft, 27 - third rotating shaft, 28 - fourth rotating shaft, 29 - fourth gear, 30 - fifth gear, 31 - sixth gear, 32 - protective cylinder, 33 - third cover plate. Detailed implementation manners

[0044] To enable those of ordinary skill in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0045] Embodiment 1:

[0046] A method for automatic positioning and fragmentation screening of rocks applicable to a Hopkinson bar, comprising the following steps:

[0047] S1: Using a specimen positioning device to accurately position and impact-crush the specimen;

[0048] S2: Automatically collecting the fragments after the specimen is broken into an automatic screening device for screening, and the automatic screening device is located below the specimen positioning device.

[0049] Among them, the specimen positioning device is as shown in the attached Figures 1-10 figure, and specifically includes a hollow housing 1. Installation through holes 5 matching the incident bar 3 and the transmission bar 4 are respectively opened on the front and rear sides of the housing 1; during the experiment, the incident bar 3 and the transmission bar 4 are inserted into the corresponding installation through holes 5; an electromagnetic impact device 6 and an arm 7 for clamping the specimen are provided in the housing 1. The electromagnetic impact device 6 is located on the left side wall or the rear side wall of the housing 1. The arm 7 is rotatably arranged between the front and rear side walls of the housing 1, and the end of the arm 7 close to the specimen is located below the electromagnetic impact device 6; a discharge port 101 is opened at the bottom of the housing 1, and the automatic screening device is located below the discharge port 101; after the specimen is positioned and impact-crushed in the housing 1, the generated fragments fall out of the housing 1 through the discharge port 101, and the fragments after the specimen is broken are collected into the automatic screening device for screening, and the proportion of fragments of different particle sizes can be counted.

[0050] Specifically, the electromagnetic impact device 6 includes a mounting shell 601 fixedly arranged on the inner side wall of the shell 1. A first mounting groove 602 is formed at the bottom of the mounting shell 601, and an electromagnet is provided at the top of the first mounting groove 602. A hammer 603 made of metal is arranged in the first mounting groove 602. A plurality of first springs 604 are fixedly arranged at the top of the hammer 603, and one end of the first spring 604 away from the hammer 603 is fixedly connected to the top of the first mounting groove 602. When the electromagnet at the top of the first mounting groove 602 is energized, it generates magnetism to adsorb the hammer 603, keeping the hammer 603 at a relatively high position. A laser emitting device 8 is also mounted on the inner side wall of the shell 1. The laser emitting device 8 can locate the specimen to be flush with the incident bar 3 and the transmission bar 4. It only needs to ensure that when the protective arm 7 swings to the horizontal position, it just blocks the laser to ensure that the specimen is flush with the incident bar 3 and the transmission bar 4. When the protective arm 7 clamping the specimen blocks the laser emitted by the laser emitting device 8, the specimen is flush with the incident bar 3 and the transmission bar 4. The power supply of the electromagnet at the top of the first mounting groove 602 is disconnected, and the hammer 603 falls under the action of gravity, hitting the protective arm 7 to make the protective arm 7 release the specimen. At this time, the specimen is not under any confining pressure. At the same time, the incident bar 3 starts to impact the specimen, and the shell 1 can prevent the fragments generated after the specimen breaks from splashing.

[0051] More specifically, the protective arm 7 includes a swing rod 701 and a clamping assembly for clamping the specimen. A mounting shaft 9 is fixedly arranged between the front and rear side walls of the shell 1. A rotating hole 702 is formed at one end of the swing rod 701 away from the clamping assembly. The mounting shaft 9 penetrates through the rotating hole 702, and the swing rod 701 is rotationally connected to the mounting shaft 9 through the rotating hole 702. In order to prevent the swing rod 701 from moving along the axial direction of the mounting shaft 9, the center of the mounting shaft 9 can be set as a section with a smaller diameter, and the end of the swing rod 701 is stuck on the small-diameter section, so as to ensure that the swing rod 701 can swing freely and will not move along the axial direction of the mounting shaft 9 during the swinging process.

[0052] The clamping assembly includes an upper semi-circular clamping ring 703 and a lower semi-circular clamping ring 704. One end of the lower semi-circular clamping ring 704 corresponding to the upper semi-circular clamping ring 703 is movably connected through a tenon 705 and a buckle 706. The tenon 705 and the buckle 706 are engaged with each other, and the tenon 705 is located directly below the hammer 603. Without external force, the tenon 705 and the buckle 706 can be engaged together, so that the upper semi-circular clamping ring 703 and the lower semi-circular clamping ring 704 are fixed together. A cylindrical specimen is clamped and fixed between the upper semi-circular clamping ring 703 and the lower semi-circular clamping ring 704. When the hammer 603 strikes the tenon 705, the tenon 705 releases the buckle 706, and the corresponding ends of the upper semi-circular clamping ring 703 and the lower semi-circular clamping ring 704 are separated. A spring is also provided between the tenon 705 and the lower semi-circular clamping ring 704. One end of the spring is connected to the tenon 705, and the other end is connected to the lower semi-circular clamping ring 704, aiming to reset the tenon 705 under the action of the spring after being struck by the hammer 603.

[0053] The other ends of the lower semi-circular clamping ring 704 corresponding to the upper semi-circular clamping ring 703 are respectively provided with a first connecting arm 707 and a second connecting arm 708. The first connecting arm 707 and the second connecting arm 708 are rotatably connected. Specifically, a protrusion is provided upward on the first connecting arm 707, and a rotating hole is provided at the protrusion. The second connecting arm 708 adopts a structure of two cross bars and one longitudinal bar, and the longitudinal bar is inserted into the rotating hole of the protrusion on the first connecting arm 707, so as to ensure that the first connecting arm 707 and the second connecting arm 708 can rotate.

[0054] An adsorption magnet 709 is fixedly provided at one end of the first connecting arm 707 away from the lower semi-circular clamping ring 704. One end of the adsorption magnet 709 away from the first connecting arm 707 is fixedly connected to the swing rod 701, that is, the lower semi-circular clamping ring 704, the first connecting arm 707, the adsorption magnet 709 and the swing rod 701 are fixedly connected to form an integral structure.

[0055] One end of the lower semi-circular clamping ring 704 close to the first connecting arm 707 is provided with two connecting columns 7041. Each connecting column 7041 is provided with a second installation groove 7042. A second spring 7043 is installed in the second installation groove 7042. A short column 7044 is fixedly arranged at the free end of the second spring 7043. That is, one end of the second spring 7043 is fixedly connected to the end of the second installation groove 7042, and the other end of the second spring 7043 is fixedly connected to the short column 7044. The short column 7044 penetrates through the second installation groove 7042. Two connecting plates 7031 matching the short column 7044 are fixedly arranged at one end of the upper semi-circular clamping ring 703 close to the second connecting arm 708. When the lower semi-circular clamping ring 704 and the upper semi-circular clamping ring 703 are fixedly combined together, the second spring 7043 is compressed. One end of the short column 7044 away from the second spring 7043 is also located in the second installation groove 7042, and the connecting column 7041 is attached to the connecting plate 7031. When one end of the lower semi-circular clamping ring 704 and the upper semi-circular clamping ring 703 provided with the tenon 705 and the buckle 706 are separated, the second spring 7043 resumes deformation. The short column 7044 pushes the connecting plate 7031 under the action of the second spring 7043, further separating the lower semi-circular clamping ring 704 from the upper semi-circular clamping ring 703. At the same time, the adsorption magnet 709 adsorbs the upper semi-circular clamping ring 703. On the one hand, it can promote the separation of the lower semi-circular clamping ring 704 from the upper semi-circular clamping ring 703. On the other hand, it can prevent the upper semi-circular clamping ring 703 from shaking back and forth.

[0056] Based on the sample positioning device in this embodiment, the specific operations of step S1 include the following steps

[0057] S101: Clamp and fix the sample between the lower semi-circular clamping ring 704 and the upper semi-circular clamping ring 703, and the tenon 705 and the buckle 706 can be engaged together; lower the protective arm 7 from the highest point and let it swing freely;

[0058] S102: When the protective arm 7 blocks the laser emitted by the laser emitting device 8, disconnect the power supply of the electromagnet at the top of the first installation groove 602. The hammer 603 falls under the action of gravity and strikes the tenon 705 on the protective arm 7. The tenon 705 releases the buckle 706, and the corresponding ends of the upper semi-circular clamping ring 703 and the lower semi-circular clamping ring 704 are separated; at the same time, the second spring 7043 resumes deformation. The short column 7044 pushes the connecting plate 7031 under the action of the second spring 7043, further separating the lower semi-circular clamping ring 704 from the upper semi-circular clamping ring 703. The adsorption magnet 709 adsorbs the upper semi-circular clamping ring 703; the sample is released and is not clamped by the protective arm 7

[0059] S103: While the protective arm 7 releases the sample, use the incident rod 3 to strike the sample to break the sample.

[0060] Furthermore, after the sample is impact-crushed within the housing 1, the generated fragments fall out of the housing 1 through the discharge port 101. The fragments after crushing the sample are collected into an automatic screening device for screening, and the proportion of fragments with different particle sizes can be counted. In this embodiment, an existing automatic screening device can be used for the automatic screening device.

[0061] Embodiment 2:

[0062] Based on Embodiment 1, the automatic screening device used in this embodiment is as shown in the appendix Figures 10-16 As shown, the automatic screening device specifically includes a mounting frame 10. The mounting frame 10 is of an L-shaped structure, and the front side and the rear side are arranged in parallel. Sliding through holes 11 are symmetrically formed in the front side wall and the rear side wall of the mounting frame 10. A hydraulic rod 12 is installed on the inner side wall of one end of the mounting frame 10 away from the vertical section. The output end of the hydraulic rod 12 is hinged to a screening component. Positioning pins 13 are fixedly provided on both the front side and the rear side of the screening component. The positioning pins 13 penetrate through the corresponding sliding through holes 11, and a limiting plate 14 is fixedly provided at one end of the positioning pin 13 located outside the mounting frame 10. The hydraulic rod 12 is hinged to the bottom of the screening component. Under the action of the hydraulic rod 12, the positioning pins 13 and the limiting plate 14, the screening component can first move along the horizontal section of the L-shaped sliding through hole 11. When the screening component enters the arc section of the sliding through hole 11, an included angle is generated by the relative rotation between the bottom of the screening component and the end of the hydraulic rod 12. At this time, the horizontal thrust generates an upward component force on the screening component, and the screening component enters the vertical section of the L-shaped sliding through hole 11.

[0063] More specifically, the screening component includes a housing 15. The top of the housing 15 is detachably provided with a first cover plate 16 through a buckle. The center of the first cover plate 16 is of an open structure, and a second cover plate 17 is detachably connected to the center opening of the first cover plate 16 through a buckle. A first screen 18, a second screen 19 and a third screen 20 are sequentially sleeved inside the housing 15 from the inside to the outside. The second cover plate 17 is matched with the first screen 18. The function of the second cover plate 17 is to seal the top of the first screen 18 to prevent sample fragments from entering other screens. The function of the first cover plate 17 is to seal the second screen 19 and the third screen 20, also to prevent sample fragments from entering other screens. A driving component for simultaneously driving the first screen 18, the second screen 19 and the third screen 20 to rotate is provided at the bottom of the housing 15.

[0064] The driving assembly includes a driving motor 21 which is located outside the housing 15. A first rotating shaft 22 is connected to the output shaft of the driving motor 21. A first gear 23, a second gear 24 and a third gear 25 are fixedly sleeved on the first rotating shaft 22 in sequence from top to bottom. The outer diameter of the second gear 24 is larger than the outer diameters of the first gear 23 and the third gear 25, and the outer diameters of the first gear 23 and the third gear 25 are the same.

[0065] A second rotating shaft 26 is fixedly provided at the bottom of the third screen 20. A third rotating shaft 27 is fixedly provided at the bottom of the second screen 19. The third rotating shaft 27 is sleeved inside the second rotating shaft 26, and the bottom end of the third rotating shaft 27 is located outside the second rotating shaft 26. A fourth rotating shaft 28 is fixedly provided at the bottom of the first screen 18. The fourth rotating shaft 28 is sleeved inside the third rotating shaft 27, and the bottom of the fourth rotating shaft 28 is located outside the third rotating shaft 27. The second rotating shaft 26, the third rotating shaft 27 and the fourth rotating shaft 28 all penetrate through the bottom of the housing 15.

[0066] A fourth gear 29 is fixedly sleeved outside the second rotating shaft 26. A part of the third rotating shaft 27 located outside the second rotating shaft 26 is fixedly sleeved with a fifth gear 30. A part of the fourth rotating shaft 28 located outside the third rotating shaft 27 is fixedly sleeved with a sixth gear 31. The fourth gear 29, the fifth gear 30 and the sixth gear 31 are all located outside the housing 15. The fourth gear 29 meshes with the first gear 23, the fifth gear 30 meshes with the second gear 24, and the sixth gear 31 meshes with the third gear 25, forming a gear set which rotates synchronously under the action of the driving motor 21, thereby driving the first screen 18, the second screen 19 and the third screen 20 to rotate synchronously. Since the outer diameters of the fourth gear 29, the fifth gear 30 and the sixth gear 31 are different, the rotation speeds of two adjacent screens among the first screen 18, the second screen 19 and the third screen 20 are different, improving the screening efficiency.

[0067] Further, a protection cylinder 32 is fixedly provided at the bottom of the housing 15. The first gear 23, the second gear 24, the third gear 25, the fourth gear 29, the fifth gear 30 and the sixth gear 31 are all located inside the protection cylinder 32. A third cover plate 33 is provided at the bottom of the protection cylinder 32. The first rotating shaft 22 penetrates through the third cover plate 33. The output end of the hydraulic rod 12 is connected to the bottom of the cover plate 33. The protection cylinder 32 and the third cover plate 33 can protect the gear set. The output end of the hydraulic rod 12 is hingedly connected to the bottom of the third cover plate 33.

[0068] Further, pressure sensors (not shown in the figure) are provided at the bottoms of the first screen 18, the second screen 19, and the third screen 20, which can directly and quickly read out the mass of the fragments remaining in each screen, facilitating statistics.

[0069] When the automatic screening device in this embodiment is in use, the hydraulic rod 12 drives the entire screening assembly to move along the sliding through-hole 11, so that the first screen 20 is located below the discharge port 101 at the bottom of the housing of the sample positioning device. The second cover plate 17 is opened, and all the sample fragments are collected into the first screen 20. After the collection is completed, the second cover plate 17 is covered, and then the entire screening assembly is moved to the horizontal section of the mounting frame 10 by the hydraulic rod 12. The drive motor 21 is started to drive the gear set to rotate, thereby driving the first screen 18, the second screen 19, and the third screen 20 to rotate to screen the sample fragments. After the screening is completed, the mass of the fragments remaining in each screen can be directly and quickly read out by the pressure sensors at the bottoms of the first screen 18, the second screen 19, and the third screen 20.

[0070] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification is only to illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and all these changes and improvements fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. A method for automatic positioning of rocks and screening of fragments applicable to a Hopkinson bar, characterized in that, it includes the following steps, S1: Use a specimen positioning device to accurately position and impact-crush the specimen; Among them, the specimen positioning device includes a hollow housing (1), and mounting through holes (5) matching the incident bar (3) and the transmission bar (4) are respectively opened on the front and rear sides of the housing (1); an electromagnetic impact device (6) and an arm (7) for clamping the specimen are provided inside the housing (1), the electromagnetic impact device (6) is located on the left side wall or the rear side wall of the housing (1), the arm (7) is rotatably arranged between the front and rear side walls of the housing (1), and the end of the arm (7) close to the specimen is located below the electromagnetic impact device (6); S2: Automatically collect the fragments after crushing the specimen into an automatic screening device for screening, and the automatic screening device is located below the specimen positioning device; Among them, the specific operation of step S1 includes the following steps, S101: Use the arm (7) to clamp and fix the specimen, and make the arm (7) swing freely inside the housing (1); S102: When the arm (7) rotates to align the specimen with the incident bar (3) and the transmission bar (4), use the electromagnetic impact device (6) to strike the arm (7) to release the specimen from the arm (7); S103: While the arm (7) releases the specimen, use the incident bar (3) to strike the specimen to crush the specimen; The electromagnetic impact device (6) includes a mounting shell (601), a first mounting groove (602) is opened at the bottom of the mounting shell (601), and an electromagnet is provided at the top of the first mounting groove (602); a hammer (603) made of metal is provided in the first mounting groove (602), and a plurality of groups of first springs (604) are fixedly arranged at the top of the hammer (603), and the end of the first spring (604) away from the hammer (603) is fixedly connected to the top of the first mounting groove (602); The arm (7) includes a swing rod (701) and a clamping component for clamping the specimen. The clamping component includes an upper semi-circular clamping ring (703) and a lower semi-circular clamping ring (704). The corresponding ends of the lower semi-circular clamping ring (704) and the upper semi-circular clamping ring (703) are movably connected by a tenon (705) and a buckle (706). When the hammer (603) strikes the tenon (705), the tenon (705) releases the buckle (706), and the corresponding ends of the upper semi-circular clamping ring (703) and the lower semi-circular clamping ring (704) are separated.

2. The method for automatic positioning of rocks and screening of fragments applicable to a Hopkinson bar according to claim 1, characterized in that: A mounting shaft (9) is fixedly arranged between the front and rear side walls of the housing (1). A rotating hole (702) is opened at the end of the swing rod (701) away from the clamping component. The mounting shaft (9) penetrates through the rotating hole (702), and the swing rod (701) is rotatably connected to the mounting shaft (9) through the rotating hole (702).

3. The automatic rock positioning and fragment screening method applicable to a Hopkinson bar according to claim 2, characterized in that: at the other ends of the lower semi-circular clamping ring (704) and the upper semi-circular clamping ring (703) corresponding to each other, a first connecting arm (707) and a second connecting arm (708) are respectively provided. The first connecting arm (707) is rotatably connected to the second connecting arm (708). And at the end of the first connecting arm (707) far from the lower semi-circular clamping ring (704), an adsorption magnet (709) is fixedly provided. The end of the adsorption magnet (709) far from the first connecting arm (707) is fixedly connected to the swing rod (701).

4. The automatic rock positioning and fragment screening method applicable to a Hopkinson bar according to claim 3, characterized in that: at one end of the lower semi-circular clamping ring (704) close to the first connecting arm (707), two connecting columns (7041) are provided. A second installation groove (7042) is formed in each connecting column (7041). A second spring (7043) is installed in the second installation groove (7042). The free end of the second spring (7043) is fixedly provided with a short column (7044). The short column (7044) penetrates through the second installation groove (7042). At one end of the upper semi-circular clamping ring (703) close to the second connecting arm (708), two connecting plates (7031) matching the short column (7044) are fixedly provided.

5. The automatic rock positioning and fragment screening method applicable to a Hopkinson bar according to claim 1, characterized in that: a discharge port (101) is formed at the bottom of the housing (1), and the automatic screening device is located below the discharge port (101); the automatic screening device includes an installation frame (10). The installation frame (10) has an L-shaped structure. And sliding through holes (11) are symmetrically formed in the front side wall and the rear side wall of the installation frame (10). A hydraulic rod (12) is installed on the inner side wall of the end of the installation frame (10) far from the vertical section. The output end of the hydraulic rod (12) is connected to a screening assembly. Positioning pins (13) are fixedly provided on the front side and the rear side of the screening assembly. The positioning pins (13) penetrate through the corresponding sliding through holes (11). And a limiting plate (14) is fixedly provided at the end of the positioning pin (13) located outside the installation frame (10).

6. The automatic rock positioning and fragment screening method applicable to a Hopkinson bar according to claim 5, characterized in that: The screening assembly includes a housing (15). A first cover plate (16) is detachably provided at the top of the housing (15). The center of the first cover plate (16) is an opening structure, and a second cover plate (17) is detachably connected to the opening at the center of the first cover plate (16). Inside the housing (15), a first screen (18), a second screen (19), and a third screen (20) are sequentially sleeved from the inside out. The second cover plate (17) matches the first screen (18). A driving assembly is provided at the bottom of the housing (15) for simultaneously driving the first screen (18), the second screen (19), and the third screen (20) to rotate.

7. The automatic rock positioning and fragment screening method applicable to a Hopkinson bar according to claim 6, characterized in that: The driving assembly includes a driving motor (21). A first rotating shaft (22) is connected to the output shaft of the driving motor (21). A first gear (23), a second gear (24), and a third gear (25) are sequentially and fixedly sleeved on the first rotating shaft (22) from top to bottom. The outer diameter of the second gear (24) is different from the outer diameters of the first gear (23) and the third gear (25). A second rotating shaft (26) is fixedly provided at the bottom of the third screen (20). A third rotating shaft (27) is fixedly provided at the bottom of the second screen (19). The third rotating shaft (27) is sleeved inside the second rotating shaft (26), and the bottom end of the third rotating shaft (27) is located outside the second rotating shaft (26). A fourth rotating shaft (28) is fixedly provided at the bottom of the first screen (18). The fourth rotating shaft (28) is sleeved inside the third rotating shaft (27), and the bottom of the fourth rotating shaft (28) is located outside the third rotating shaft (27). A fourth gear (29) is fixedly sleeved outside the second rotating shaft (26). A fifth gear (30) is fixedly sleeved on the part of the third rotating shaft (27) located outside the second rotating shaft (26). A sixth gear (31) is fixedly sleeved on the part of the fourth rotating shaft (28) located outside the third rotating shaft (27). The fourth gear (29) meshes with the first gear (23), the fifth gear (30) meshes with the second gear (24), and the sixth gear (31) meshes with the third gear (25).

8. The automatic rock positioning and fragment screening method applicable to a Hopkinson bar according to claim 7, characterized in that: A protection cylinder (32) is fixedly provided at the bottom of the housing (15). The first gear (23), the second gear (24), the third gear (25), the fourth gear (29), the fifth gear (30), and the sixth gear (31) are all located inside the protection cylinder (32). A third cover plate (33) is provided at the bottom of the protection cylinder (32). The first rotating shaft (22) penetrates through the third cover plate (33). The output end of the hydraulic rod (12) is connected to the bottom of the third cover plate (33).

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