Rock sample cutting device for testing

Abstract

The utility model relates to the technical field of rock mechanics testing, and discloses a rock sample cutting device for testing, which comprises a workbench, a translation feeding mechanism and a cutting mechanism, the translation feeding mechanism comprises a bearing table, the bearing table is in sliding connection with the workbench, and the cutting mechanism comprises a supporting seat, a double-thread screw, a transmission shaft and two cutting components. The cutting assembly comprises a sliding seat, a supporting arm and a cutting motor which are sequentially connected, cutting cutterheads are connected to an output shaft of the cutting motor, the distance between the two cutting cutterheads can be adjusted when the double-thread screw is rotated, and the height of the cutting cutterheads can be adjusted when the transmission shaft is rotated; according to the rock sample cutting device for testing, crack processing on a standard rock sample can be rapidly completed with high precision, and a rock tensile test can be completed on the processed rock sample in a pressure and tension conversion mode.

Description

Technical Field

[0001] The utility model relates to the technical field of rock mechanics testing, in particular to a rock sample cutting device for testing. Background Technique

[0002] When studying the mechanical properties of rocks, the tensile test is one of the more commonly used test methods, which can detail the behavior of rocks under tensile loads, including their strength, deformation characteristics, and failure modes, etc.

[0003] Traditional tensile tests mainly have two forms: indirect tests and direct tests. Among them, indirect test methods (such as the Brazilian splitting test and the three-point bending test) have a relatively wide range of applications and can simulate the stress conditions of rocks in actual engineering. However, indirect test methods also have some limitations. For example, the non-uniform stress distribution during the test and the requirements for the geometric shape of the test specimens limit the scope of application, etc. The direct test is to clamp both ends of the test specimen and then apply a tensile load until failure. However, traditional direct tensile test methods also have some challenges. For example, limited by the shape and size of the test specimens, it may lead to inaccurate test results and poor repeatability.

[0004] In response, we have studied a method for conducting a tensile test on a rock sample by converting pressure into tension. This method is to first prepare a rock sample 1 as shown in Figure 1 Two upper cracks 2 are symmetrically machined along the center line on the upper surface of the standard rock sample, and two lower cracks 3 are symmetrically machined along the center line on the lower surface of the standard rock sample. The depths of the upper cracks 2 and the lower cracks 3 are equal and greater than half of the height of the standard rock sample. The distance between the two upper cracks 2 is less than the distance between the two lower cracks 3, thereby forming a tension part 4 between the upper crack 2 and the lower crack 3 on the same side; then the prepared rock sample 1 is placed on the test bench. When placed, as shown in Figure 2 Two pads 5 are installed at both ends of the lower surface and the middle part of the upper surface as shown. When pressure is applied to the test bench, it can be converted into tension on the tension part 4 to complete the tensile test of this part of the rock. This method overcomes the difficulties in clamping the direct tensile test and the influence of pressure concentration at the pressure bar on the test results in the indirect test, and simplifies the test operation.

[0005] In the above method for conducting a tensile test on a rock specimen by converting pressure to tensile force, the prepared rock specimen 1 is required to be a symmetric model. This is to ensure that although the pressure and tensile force are not in the same straight line during the test, due to the symmetry of the specimen, there is no bending moment in the tensile part 4, and the tensile part 4 is only damaged by pure tensile force. Therefore, there are relatively high precision requirements for the processing of the upper crack 2 and the lower crack 3. Currently, when processing the upper crack 2 and the lower crack 3, a hacksaw or a cutting machine tool is used to process each crack one by one. During the processing, it is necessary to repeatedly measure and confirm the processing position and depth, the processing process is relatively complex, and it is difficult to ensure the processing precision due to the influence of measurement errors. Summary of the Invention

[0006] The purpose of the present utility model is to overcome the deficiencies of the prior art and provide a cutting device for a rock specimen for testing, which can quickly complete the processing of cracks on a standard rock specimen. The prepared rock specimen can complete the rock tensile test through the pressure-tensile force conversion method, and it is convenient to operate and has high processing precision.

[0007] The purpose of the present utility model is achieved through the following technical solutions:

[0008] A cutting device for a rock specimen for testing includes a workbench, a translation feeding mechanism, and a cutting mechanism; the translation feeding mechanism includes a bearing table, and the bearing table is slidably connected to the workbench; the cutting mechanism includes a support seat, a double-threaded screw rod, a transmission shaft, and two cutting components. The support seat is fixedly connected to the workbench, the transmission shaft is rotatably arranged on the support seat, the transmission shaft is perpendicular to the sliding direction of the bearing table, the double-threaded screw rod is arranged parallel to the transmission shaft, both ends of the transmission shaft are fixedly sleeved with connecting rods, and both ends of the double-threaded screw rod are respectively rotatably connected to the two connecting rods. The double-threaded screw rod includes a left-handed thread section and a right-handed thread section. The cutting component includes a sliding seat, a support arm, a cutting motor, and a cutting tool disc. One end of the support arm is connected to the sliding seat, the cutting motor is fixedly installed at the other end of the support arm, the cutting tool disc is fixedly installed on the output shaft of the cutting motor, the two sliding seats are respectively threadedly connected to the left-handed thread section and the right-handed thread section, and both sliding seats are slidably connected to the transmission shaft.

[0009] Furthermore, one end of the support arm is slidably connected to the sliding seat, the sliding direction of the support arm on the sliding seat is parallel to the transmission shaft, and a positioning screw rod is rotatably arranged on the sliding seat, and the positioning screw rod is threadedly connected to the support arm.

[0010] Furthermore, the cutting mechanism further includes a distance adjustment motor, and the distance adjustment motor is used to drive the double-threaded screw rod to rotate.

[0011] Further, a depth adjustment motor and a worm and worm gear reducer are fixedly arranged on the workbench. The output shaft of the depth adjustment motor is fixedly connected to the input shaft of the worm and worm gear reducer, and the output shaft of the worm and worm gear reducer is fixedly connected to one end of the transmission shaft.

[0012] Further, the translation and feeding mechanism further includes a feeding motor and a feeding lead screw. The feeding motor is fixedly connected to the workbench, the feeding lead screw is rotatably connected to the workbench, the output shaft of the feeding motor is fixedly connected to one end of the feeding lead screw, and the feeding lead screw is in threaded connection with the bottom of the bearing table.

[0013] Further, clamping assemblies are symmetrically arranged on both sides of the bearing table. The clamping assembly includes a vertical plate. The bottom end of the vertical plate is fixedly connected to the bearing table. A plurality of clamping screws are in threaded connection with the vertical plate, and one end of the clamping screw extending above the bearing table is rotatably connected to a pressing plate.

[0014] The beneficial effects of the present utility model are:

[0015] The rock sample cutting device for testing includes a workbench, a translation and feeding mechanism, and a cutting mechanism. The cutting mechanism includes a support seat, a double-threaded lead screw, a transmission shaft, and two cutting assemblies. The cutting assembly includes a sliding seat, a support arm, a cutting motor, and a cutting cutter head. The translation and feeding mechanism includes a bearing table. The bearing table is slidably connected to the workbench, and the bearing table is used for carrying and clamping a standard rock sample to be cut. After adjusting the heights of the two cutting cutter heads and the distance between the two cutting cutter heads, when the bearing table moves forward and slides, two cracks on one side of the rock sample can be processed simultaneously.

[0016] The double-threaded lead screw includes a left-handed thread section and a right-handed thread section. The sliding seats of the two cutting assemblies are respectively in threaded connection with the left-handed thread section and the right-handed thread section. Combined with the guiding action of the transmission shaft, it constitutes a lead screw and nut mechanism. By rotating the double-threaded lead screw, the two sliding seats can be controlled to approach or move away from each other, so as to adjust the distance between the two cutting cutter heads to correspondingly process two cracks at different distances; rotating the transmission shaft can drive the double-threaded lead screw and the sliding seat to rotate, so as to adjust the height of the cutting cutter head to meet the processing requirements of cracks with different depths.

[0017] The provided distance adjustment motor can automatically adjust the distance between the two cutting cutter heads, the depth adjustment motor can automatically adjust the height of the cutting cutter head, and the feeding motor can automatically adjust the feeding action of the bearing table. While ensuring the cutting accuracy, it can also complete the automatic cutting process of cracks with deeper depths or wider widths as required through multiple step-by-step cutting forms, and the applicable size processing range is relatively wide. Description of the Drawings

[0018] Figure 1The structural schematic diagram of the rock specimen to be processed and prepared for a rock specimen cutting device for testing of the present utility model;

[0019] Figure 2 is Figure 1 The schematic diagram of the principle when the shown rock specimen is subjected to a tensile test by applying pressure;

[0020] Figure 3 The overall structural schematic diagram of a rock specimen cutting device for testing of the present utility model;

[0021] Figure 4 The structural schematic diagram of the cutting mechanism in a rock specimen cutting device for testing of the present utility model;

[0022] Figure 5 The structural schematic diagram of the translation feeding mechanism in a rock specimen cutting device for testing of the present utility model;

[0023] In the figure, 1 - rock specimen, 2 - upper crack, 3 - lower crack, 4 - tension part, 5 - backing plate, 6 - workbench, 10 - translation feeding mechanism, 11 - bearing platform, 12 - vertical plate, 13 - clamping screw, 14 - pressing plate, 15 - feeding motor, 16 - feeding lead screw, 20 - cutting mechanism, 21 - support seat, 22 - double-threaded screw, 23 - transmission shaft, 24 - connecting rod, 25 - centering and positioning seat, 26 - sliding seat, 27 - support arm, 28 - cutting motor, 29 - cutting tool disc, 30 - one-word laser lamp, 31 - positioning screw, 32 - distance adjusting motor, 33 - gear A, 34 - gear B, 35 - depth adjusting motor, 36 - worm and worm gear reducer. Specific embodiments

[0024] The technical solution of the present utility model will be further described in detail below with reference to the accompanying drawings, but the protection scope of the present utility model is not limited to the following.

[0025] As Figures 3 to 5 shown, a rock specimen cutting device for testing includes a workbench 6, a translation feeding mechanism 10 and a cutting mechanism 20.

[0026] As Figure 5 shown, the translation feeding mechanism 10 includes a bearing platform 11. The bearing platform 11 is slidably connected to the workbench 6, and the bearing platform 11 is used for bearing and clamping a standard rock specimen to be cut.

[0027] As Figure 4As shown, the cutting mechanism 20 includes a support base 21, a double-threaded screw 22, a transmission shaft 23, and two cutting assemblies. There are two support bases 21, which are fixedly installed at one end on the top surface of the workbench 6; both ends of the transmission shaft 23 are rotatably connected to the two support bases 21 respectively, and the transmission shaft 23 is perpendicular to the sliding direction of the bearing table 11; the double-threaded screw 22 is arranged parallel to the transmission shaft 21, and both ends of the transmission shaft 21 are fixedly sleeved with connecting rods 24, and both ends of the double-threaded screw 22 are rotatably connected to the two connecting rods 24 respectively. When the transmission shaft 23 rotates, the double-threaded screw 22 can be driven to rotate together through the connecting rods 24.

[0028] The above-mentioned cutting assembly includes a sliding seat 26, a support arm 27, a cutting motor 28, and a cutting tool disc 29. One end of the support arm 27 is connected to the sliding seat 26, the cutting motor 28 is fixedly installed at the other end of the support arm 27, the cutting tool disc 29 is fixedly installed on the output shaft of the cutting motor 28, and the cutting motor 28 can drive the cutting tool disc to rotate for cutting the standard rock sample. The double-threaded screw 23 includes a left-handed thread section and a right-handed thread section. The two sliding seats 26 are respectively threadedly connected to the left-handed thread section and the right-handed thread section, and both sliding seats 26 are slidably connected to the transmission shaft 23. Thus, the two sliding seats 26 form a screw-nut mechanism on the double-threaded screw 22 and the transmission shaft 23, and the transmission shaft 23 serves as a sliding limit guide rod. When the double-threaded screw 22 is driven to rotate, the two sliding seats 26 can approach or move away from each other.

[0029] When the rock sample cutting device for testing is in use, the standard rock sample to be cut is clamped on the bearing table 11, and the central plane of the standard rock sample to be cut is aligned with the center point between the two tool discs 29 and kept parallel to the sliding direction of the bearing table 11. By rotating the double-threaded screw 23, the two sliding seats 26 can approach or move away from each other, and further, the two cutting tool discs 29 can approach or move away from each other, so as to adjust the distance between the two cutting tool discs 29, that is, corresponding to adjusting the distance between the two cracks to be processed; by rotating the transmission shaft 21, the cutting assembly can be driven to rotate integrally around the transmission shaft 21, and further adjust the height of the cutting tool disc 29, that is, corresponding to adjusting the processing depth of the crack to be processed. After the adjustment is completed, the bearing table 11 is slid forward, and when the standard rock sample passes through the positions of the two tool discs 29, the cutting of the two cracks is completed simultaneously, and the processed cracks are symmetric about the central plane of the standard rock sample.

[0030] During specific implementation, a centering and positioning seat 25 can be fixedly connected to the middle of the transmission shaft 23. The centering and positioning seat 25 is rotatably connected to the middle of the double-threaded screw rod 23. The left-handed thread section and the right-handed thread section are respectively arranged on both sides of the centering and positioning seat 25. Two sliding seats 26 are symmetrically arranged on both sides of the centering and positioning seat 25. When the double-threaded screw rod 23 is rotated to make the two sliding seats 26 slide, the moving distances of the two sliding seats 26 relative to the centering and positioning seat 25 are the same. The centering and positioning seat 25 can be used as a positioning reference. An L-shaped laser lamp 30 is rotatably arranged on the centering and positioning seat 25. The L-shaped laser lamp 30 is used to project a straight indicating line in front of its lamp head. The rotation axis of the L-shaped laser lamp 30 on the centering and positioning seat 25 is parallel to the transmission shaft 23. The L-shaped laser lamp 30 is arranged above and in front of the center line of the bearing table 11. Rotating the L-shaped laser lamp 30 can keep the straight indicating line projected by its lamp head irradiating on the standard rock sample on the bearing table 11.

[0031] When the rock sample cutting device for testing cuts two cracks, it can be processed according to the following steps:

[0032] S1. Measure the standard rock sample, determine the central plane on the standard rock sample (this central plane is the symmetry plane between the two upper cracks 2 to be processed and between the two lower cracks 3), and draw positioning lines at the positions where the central plane intersects the four faces of the standard rock sample.

[0033] S2. Place the standard rock sample with the drawn positioning lines on the bearing table 11, adjust the position of the standard rock sample until the straight indicating line projected when the L-shaped laser lamp 30 is rotated always coincides with the drawn positioning lines, and complete the clamping. During specific implementation, as Figure 5 shown, clamping components are symmetrically arranged on both sides of the bearing table 11. The clamping components include vertical plates 12. The bottom ends of the vertical plates 12 are fixedly connected to the bearing table 11. A number of clamping screw rods 13 are threadedly connected to the vertical plates 12. One end of the clamping screw rod 13 extending into the upper part of the bearing table 11 is rotatably connected to a pressing plate 14. When in use, the standard rock sample to be processed is placed between the two vertical plates 12 on the bearing table. Rotating the clamping screw rods 13 can drive the vertical plates 12 to extend inwards until they abut against the side surface of the standard rock sample, which can push the standard rock sample to be adjusted left and right on the bearing table 11. After the adjustment is completed, tightening the clamping screw rods 13 on the two vertical plates 12 can complete the clamping of the standard rock sample. After the clamping is completed, slide the bearing table 11 and observe whether the straight indicating line always coincides with the drawn positioning lines to judge whether the rock sample on the bearing table 11 is adjusted in place.

[0034] S3. Rotate the double-threaded screw rod 22 to make the two sliding seats 26 approach or move away from each other synchronously until the two cutting discs 29 are adjusted to the set distance of the two cracks to be processed; rotate the transmission shaft 23 to drive the whole two cutting assemblies to rotate so as to adjust the height of the two cutting discs 29 until the height is adapted to the set processing depth of the two cracks to be processed.

[0035] S4. Slide the bearing table 11 forward to make the standard rock sample pass through the positions of the two cutting discs 29, thus completing the cutting of the two cracks.

[0036] The above is the cutting process of the two cracks on one side of the standard rock sample. Since the positioning lines have been drawn in the above step S1, when cutting the other two cracks, retract the bearing table 11 to turn the rock sample over, and directly repeat steps S2 to S4 to complete the cutting process of the two cracks on the other side. Thus, it can be seen that when the rock sample cutting device for testing cuts cracks in the rock sample, it can cut two cracks on the same side simultaneously, with high processing accuracy, which is beneficial to ensuring the symmetry of the processed rock sample, ensuring that the tensile part 4 is only damaged by pure tension, making the tensile test results of the pressure conversion more accurate, and the operation is convenient.

[0037] Considering factors such as the replacement of the cutting disc 29, in specific implementation, the above cutting assembly is designed as an adjustable structure. Specifically, one end of the support arm 27 far from the cutting disc 29 is slidably connected to the sliding seat 26. The sliding direction of the support arm 27 on the sliding seat 26 is parallel to the transmission shaft 23. A positioning screw rod 31 is rotatably arranged on the sliding seat 26. The positioning screw rod 31 is threadedly connected to the support arm 27. By rotating the positioning screw rod 31, the installation position of the support arm 27 on the sliding seat 26 can be finely adjusted, and further the distance between the cutting disc 29 and the center line of the bearing table 11 can be adjusted to keep the distances between the two cutting discs 29 and the center line of the bearing table 11 consistent.

[0038] Furthermore, the above cutting mechanism further includes a distance adjustment motor 32, and the distance adjustment motor 32 is used to drive the double-threaded screw rod 22 to rotate. In specific implementation, the distance adjustment motor 32 can be installed on the centering positioning seat 25. A gear A 33 is fixedly sleeved on the output shaft of the distance adjustment motor 32, and a gear B 34 is fixedly sleeved in the middle of the double-threaded screw rod 22. The gear A 33 meshes with the gear B 34. The distance adjustment motor 32 is selected as a servo motor. When it rotates, it can drive the gear B 34 to rotate through the gear A 33, and further drive the double-threaded screw rod 22 to rotate to realize the automatic adjustment of the distance between the two cutting discs 29. Since the double-threaded screw rod 22, the transmission shaft 23 and the two sliding seats 26 form a lead screw-nut mechanism, the above distance adjustment can be accurately controlled by the number of rotation turns of the distance adjustment motor 32, and the stability of the subsequent cutting process can also be maintained by self-locking after the adjustment is completed.

[0039] Further, a depth adjustment motor 34 and a worm and worm gear speed reducer 35 are also fixedly arranged on the workbench 6. The output shaft of the depth adjustment motor 34 is fixedly connected to the input shaft of the worm and worm gear speed reducer 35, and the output shaft of the worm and worm gear speed reducer 35 is fixedly connected to one end of the transmission shaft 23. By driving the worm of the worm and worm gear speed reducer 35 to rotate through the depth adjustment motor 34, the transmission shaft 23 can be driven to rotate through the worm wheel of the worm and worm gear speed reducer 35, so as to drive the cutting assembly to rotate to realize the automatic adjustment of the height of the cutting cutter head 29; the provided worm and worm gear speed reducer 35 has good self-locking characteristics, which is beneficial to maintaining the stability of the cutting process after the adjustment is completed.

[0040] Further, the above-mentioned translation and feeding mechanism further includes a feeding motor 15 and a feeding lead screw 16. The feeding motor 15 is fixedly connected to the workbench 6, the feeding lead screw 16 is rotatably connected to the workbench 6, and the feeding lead screw 16 is threadedly connected to the bottom of the bearing platform 11. The output shaft of the feeding motor 15 is fixedly connected to one end of the feeding lead screw 16. The feeding lead screw 16 and the bearing platform 11 form a lead screw and nut mechanism, and the forward and backward sliding of the bearing platform 11 can be accurately and automatically controlled by the rotation of the feeding motor 15.

[0041] The settings of the above-mentioned distance adjustment motor 32, depth adjustment motor 34 and feeding motor 15 can automatically complete the subsequent cutting process after the rock sample to be processed is clamped on the bearing platform 11, and various automatic cutting conditions can also be completed as required during the automatic cutting process. For example, when the size of the rock sample to be processed is large and the depth of the crack to be cut is deep, in order to avoid the cutting cutter head 29 from breaking, it can be cut several times in a gradually deepening form, that is, first, the depth adjustment motor 34 is used to control and adjust the cutting cutter head 29 to a relatively high height, then the feeding motor 15 controls the bearing platform 11 to feed to complete the cutting and return, then the depth adjustment motor 34 controls and adjusts the cutting cutter head 26 to descend a set distance, and the feeding motor 15 controls the bearing platform 11 to feed forward and return, and the above operations are repeatedly executed until the specified depth is cut. Another example is that considering that standard rock samples of different specifications and compositions often require cracks of different widths to be processed. When the width of the crack to be processed is greater than the cutting thickness of the cutting cutter head 29, it can be cut several times in a gradually widening form, that is, first, the distance adjustment motor 32 is used to control and adjust the distance between the cutting cutter heads 29 on the adjacent or opposite sides of the two cracks, then the feeding motor 15 controls the bearing platform 11 to feed to complete the cutting and return, then the distance adjustment motor 32 controls and adjusts the cutting cutter heads 29 to move away from or close to each other to a set distance, and the feeding motor 15 controls the bearing platform 11 to feed forward and return, and the above operations are repeatedly executed until the crack of the specified width is cut. The above entire process can be realized under automatic control. At the same time, the two cutting cutter heads 29 are always symmetrical about the central plane of the standard rock sample, and the cutting accuracy can still be effectively guaranteed under multiple step-by-step cuttings.

[0042] The above are only the preferred embodiments of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be changed within the scope of the concept described herein through the above teachings or the technology or knowledge in related fields. Any changes and modifications made by those skilled in the art without departing from the spirit and scope of the present invention shall fall within the protection scope of the appended claims of the present invention.

Claims

1. A rock sample cutting device for testing, characterized in that: It includes a workbench, a translation feeding mechanism and a cutting mechanism; The translation feeding mechanism comprises a bearing platform, and the bearing platform is slidably connected to the workbench; The cutting mechanism includes a support seat, a double-threaded screw, a transmission shaft and two cutting components. The support seat is fixedly connected to the workbench, the transmission shaft is rotatably arranged on the support seat, the transmission shaft is perpendicular to the sliding direction of the bearing platform, the double-threaded screw is arranged parallel to the transmission shaft, the two ends of the transmission shaft are fixedly sleeved with connecting rods, the two ends of the double-threaded screw are rotatably connected to the two connecting rods respectively, and the double-threaded screw includes a left-handed thread section and a right-handed thread section. The cutting assembly includes a slide, a support arm, a cutting motor and a cutting disc, one end of the support arm is connected to the slide, the cutting motor is fixedly mounted on the other end of the support arm, and the cutting disc is fixedly mounted on the output shaft of the cutting motor. The two slide seats are respectively threadedly connected to the left-handed thread section and the right-handed thread section, and the two slide seats are both slidably connected to the transmission shaft.

2. A rock sample cutting device for testing according to claim 1, characterized in that: One end of the support arm is slidably connected to the slide seat, and the sliding direction of the support arm on the slide seat is parallel to the transmission shaft. A positioning screw is rotatably provided on the slide seat, and the positioning screw is threadedly connected to the support arm.

3. A rock sample cutting device for testing according to claim 1, characterized in that: The cutting mechanism also includes a pitch-adjusting motor, and the pitch-adjusting motor is used to drive the double-threaded screw to rotate.

4. A rock sample cutting device for testing according to claim 1, characterized in that: A depth adjustment motor and a worm gear reducer are also fixedly arranged on the workbench, the output shaft of the depth adjustment motor is fixedly connected to the input shaft of the worm gear reducer, and the output shaft of the worm gear reducer is fixedly connected to one end of the transmission shaft.

5. A rock sample cutting device for testing according to claim 1, characterized in that: The translation feeding mechanism also includes a feeding motor and a feeding screw. The feeding motor is fixedly connected to the workbench, the feeding screw is rotatably connected to the workbench, the output shaft of the feeding motor is fixedly connected to one end of the feeding screw, and the feeding screw is threadedly connected to the bottom of the supporting platform.

6. A rock sample cutting device for testing according to claim 1, characterized in that: Clamping assemblies are symmetrically arranged on both sides of the supporting platform, and the clamping assemblies include a vertical plate, the bottom end of which is fixedly connected to the supporting platform, a plurality of clamping screws are threadedly connected to the vertical plate, and one end of the clamping screw extending into the top of the supporting platform is rotatably connected to a pressure plate.

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