A rotary drill bit for coal mine engineering construction

Abstract

The application discloses a rotary drilling machine drill bit for coal mine engineering construction and relates to the technical field of rotary drilling machines.The rotary drilling machine drill bit comprises a conveying paddle and a drill bit body, an adjusting structure is arranged between the conveying paddle and the drill bit body, the adjusting structure comprises a hollow pipe one, a hollow pipe two, a connecting pipe one and a connecting pipe two, the hollow pipe one is fixedly connected with the drill bit body, the hollow pipe one is connected with the connecting pipe one through a plurality of bolt fasteners one, the hollow pipe two is slidably connected with the connecting pipe one, the connecting pipe two is fixedly connected with the hollow pipe two, and the connecting pipe two is connected with the conveying paddle through a plurality of bolt fasteners two, and the top of the hollow pipe one is provided with an electric telescopic rod one.The rotary drilling machine drill bit can expand the hole according to the use requirement, and can press the inside of the hole to avoid the collapse of the hole.

Description

Technical Field

[0001] This invention relates to the field of rotary drilling rig technology, and in particular to a rotary drilling rig bit for coal mine engineering construction. Background Technology

[0002] Rotary drilling rigs play a crucial role in coal mining operations. The drill bit is extremely important for the rotary drilling rig, as it can perform drilling operations according to the needs of coal mining construction.

[0003] However, traditional drill bits are at risk of hole collapse during drilling, which affects the drilling operation. In addition, traditional drill bits are subjected to great impact during drilling and lack buffering function to protect the drill bit. Therefore, this invention proposes a rotary drilling bit for coal mine engineering construction. Summary of the Invention

[0004] The main objective of this invention is to provide a rotary drilling bit for coal mine engineering construction, which can effectively solve the technical problems mentioned in the background art.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A rotary drilling rig bit for coal mine construction includes a conveyor blade and a drill bit body, wherein an adjustment structure is provided between the conveyor blade and the drill bit body.

[0007] The adjustment structure includes a hollow tube 1, a hollow tube 2, a connecting tube 1, and a connecting tube 2. The hollow tube 1 is fixedly connected to the drill bit body and is connected to the connecting tube 1 by several bolts and fasteners 1. The hollow tube 2 is slidably connected to the connecting tube 1. The connecting tube 2 is fixedly connected to the hollow tube 2 and is connected to the conveyor paddle by several bolts and fasteners 2. An electric telescopic rod 1 is provided at the top of the hollow tube 1, and one end of the electric telescopic rod 1 is fixedly connected to a fixed plate through the top of the hollow tube 1. Four connecting plates 1 are rotatably connected to the bottom of the fixed plate 1, and one end of the connecting plate 1 is rotatably connected to a base plate 1. The base plate 1 is fixedly connected to a base plate 2 by several guide rods. Several soil-breaking cones are fixedly provided on one side of the base plate 2. The hollow tube 1 is penetrated by the guide rods.

[0008] As a preferred embodiment of the present invention, the adjustment structure further includes an electric telescopic rod II, which is disposed at the top of the hollow tube II. The electric telescopic rod II is fixedly connected to a base plate III through the top of the hollow tube II. Four sets of connecting parts are rotatably disposed at the bottom of the base plate III. Each set of connecting parts consists of two connecting plates II. A shelf is rotatably connected between one end of the two connecting plates II. Two fixed tubes are fixedly connected to one side of the shelf. A movable rod is slidably disposed through the inner side of the fixed tube. The two ends of the two movable rods are fixedly connected by a fixed plate and an arc plate, respectively. A fixed block is fixedly disposed at the bottom of the fixed plate. Two springs I are disposed between the shelf and the fixed plate.

[0009] In a preferred embodiment of the present invention, the hollow tube II is penetrated by the fixed tube, the fixed plate is penetrated by the movable rod, and the spring I is located on the periphery of the corresponding movable rod.

[0010] As a preferred technical solution of the present invention, the base plate three is arranged in a "well" shape, one side of the fixing block is inclined in the horizontal direction, the inner side of the hollow tube one is cross-shaped, and the base plate one and the hollow tube one are adaptively matched.

[0011] As a preferred embodiment of the present invention, a buffer structure is provided on the inner side of the hollow tube 2 and the connecting tube 1. The buffer structure includes several springs 2 and a base. The springs 2 are disposed between the bottom of the hollow tube 2 and the inner bottom surface of the connecting tube 1. The base is slidably disposed on the inner side of the hollow tube 2. The base is fixedly connected to the connecting tube 1 by four limiting rods. An electric push rod 1 is disposed on the top of the base. A top plate is fixedly disposed at one end of the electric push rod 1. Four inclined plates are fixedly disposed at the bottom of the top plate. A pressure plate is fixedly connected to one end of the inclined plates.

[0012] In a preferred embodiment of the present invention, the hollow tube is penetrated by a limiting rod, and the pressure plate and the fixing block are adaptively matched.

[0013] As a preferred embodiment of the present invention, the pressure plate consists of two protrusions and a connecting block.

[0014] As a preferred technical solution of the present invention, a stop structure is provided on the outside of the connecting pipe one. The stop structure includes two mounting plates, which are fixedly connected to the connecting pipe one. An electric push rod two is provided on the top of the mounting plate. One end of the electric push rod two is fixedly connected to a limit plate, and the limit plate is composed of two limit posts and a horizontal plate.

[0015] As a preferred embodiment of the present invention, four limiting tubes are fixedly provided at the bottom of the hollow tube II, and the limiting tubes and the limiting posts of the limiting plate are adaptively matched.

[0016] As a preferred embodiment of the present invention, both the bolt fastener one and the bolt fastener two are composed of bolts and nuts.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. By setting an adjustment structure, it is convenient to adjust the diameter of the borehole as needed, so that the rotary drilling rig bit can have the function of enlarging the hole. At the same time, the drill bit body, together with the soil breaking cone, can improve the drilling efficiency.

[0019] 2. By setting up an arc-shaped plate in conjunction with a soil-breaking cone, it is beneficial to rotate and scrape the irregular inner wall of the hole caused by the drill bit body and the soil-breaking cone, making the inner wall of the borehole more regular and reducing the risk of hole collapse.

[0020] 3. By setting up a buffer structure in conjunction with an adjustment structure, the resistance experienced by the drill bit body can be buffered, which can further improve the service life of the drill bit body. At the same time, under the action of spring one, spring two, pressure plate and fixing block, the arc plate can perform intermittent expansion and contraction movements. This is beneficial for the arc plate to rotate and press the inner wall of the borehole after expansion under the action of the rotary drilling machine, so that the inner wall of the hole is compacted and the hole collapse is avoided.

[0021] 4. By setting a stop structure in conjunction with a buffer structure, the drill bit body can be buffered against resistance as needed or not. When the electric push rod 2 moves upward on the limit plate, the distance between the hollow tube 1 and the hollow tube 2 remains constant and does not move. When the electric push rod 2 is in the initial state on the limit plate, the distance between the hollow tube 1 and the hollow tube 2 changes continuously under the action of the spring 2 when the drill bit body is subjected to resistance.

[0022] 5. By setting a limiting tube in conjunction with a limiting plate, the position of the connecting tube can be restricted. When the limiting post of the limiting plate is inserted into the inside of the limiting tube, the drill bit body loses its buffering effect. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall three-dimensional structure of a rotary drilling rig bit for coal mine engineering construction according to the present invention;

[0024] Figure 2 This is a three-dimensional structural diagram of the conveyor blade and connecting pipe 2 of a rotary drilling rig bit for coal mine construction according to the present invention.

[0025] Figure 3 This is a three-dimensional structural diagram of the connecting pipe and the hollow pipe of a rotary drilling rig bit for coal mine construction according to the present invention.

[0026] Figure 4This is a cross-sectional three-dimensional structural diagram of the hollow tube 2 of a rotary drilling rig bit for coal mine engineering construction according to the present invention.

[0027] Figure 5 This is a cross-sectional three-dimensional structural diagram of the fixing pipe of a rotary drilling rig bit for coal mine engineering construction according to the present invention;

[0028] Figure 6 This is a three-dimensional structural diagram of the hollow tube 2 and connecting tube 1 of a rotary drilling rig bit for coal mine engineering construction according to the present invention.

[0029] Figure 7 This is a three-dimensional structural schematic diagram of the electric push rod 2 of a rotary drilling rig bit for coal mine engineering construction according to the present invention;

[0030] Figure 8 This is a schematic diagram of the overall cross-sectional three-dimensional structure of a rotary drilling rig bit for coal mine engineering construction according to the present invention;

[0031] Figure 9 This is a schematic diagram of the overall cross-sectional side view of a rotary drilling rig bit for coal mine engineering construction according to the present invention;

[0032] Figure 10 This is a schematic side view of the overall structure of a rotary drilling rig bit for coal mine construction according to the present invention.

[0033] In the diagram: 1. Conveyor paddle; 2. Drill bit body; 3. Adjustment structure; 4. Buffer structure; 5. Stop structure; 6. Hollow tube one; 7. Hollow tube two; 8. Connecting pipe one; 9. Bolt fastener one; 10. Connecting pipe two; 11. Bolt fastener two; 12. Electric telescopic rod one; 13. Fixing plate; 14. Connecting plate one; 15. Base plate one; 16. Guide rod; 17. Base plate two; 18. Breaking cone; 19. Electric telescopic rod 20. Rod 2; 21. Base Plate 3; 22. Connecting Plate 2; 23. Shelf; 24. Fixing Tube; 25. Movable Rod; 26. Fixing Plate; 27. Curved Plate; 28. Fixing Block; 29. ​​Spring 1; 30. Spring 2; 31. Chassis; 32. Limiting Rod; 33. Electric Push Rod 1; 34. Top Plate; 35. Inclined Plate; 36. Pressure Plate; 37. Mounting Plate; 38. Limiting Tube; 39. Electric Push Rod 2; 30. Limiting Plate. Detailed Implementation

[0034] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0035] like Figures 1-10 As shown, a rotary drilling rig bit for coal mine construction includes a conveyor blade 1 and a drill bit body 2, with an adjustment structure 3 provided between the conveyor blade 1 and the drill bit body 2.

[0036] The adjustment structure 3 includes a hollow tube 6, a hollow tube 7, a connecting tube 8, and a connecting tube 10. The hollow tube 6 is fixedly connected to the drill bit body 2, and the hollow tube 6 is connected to the connecting tube 8 by several bolts and fasteners 9. The hollow tube 7 is slidably connected to the connecting tube 8. The connecting tube 10 is fixedly connected to the hollow tube 7, and the connecting tube 10 is connected to the conveyor paddle 1 by several bolts and fasteners 11. An electric telescopic rod 12 is provided at the top of the hollow tube 6, and a fixed plate 13 is fixedly connected to the top of the hollow tube 6 through one end of the electric telescopic rod 12. Four connecting plates 14 are rotatably connected to the bottom of the fixed plate 13, and a base plate 15 is rotatably connected to one end of the connecting plate 14. A base plate 17 is fixedly connected to the base plate 15 by several guide rods 16. Several soil-breaking cones 18 are fixedly provided on one side of the base plate 17, and the hollow tube 6 is penetrated by the guide rods 16.

[0037] The adjustment structure 3 can adjust the diameter of the borehole as needed, enabling the rotary drilling rig bit to have the function of enlarging the hole. At the same time, the drill bit body 2, together with the soil breaking cone 18, can improve the drilling efficiency.

[0038] In this embodiment, the adjustment structure 3 also includes an electric telescopic rod 19, which is set at the top of the hollow tube 7. The electric telescopic rod 19 passes through the top of the hollow tube 7 and is fixedly connected to a base plate 20. The bottom of the base plate 20 is rotatably provided with four sets of connecting parts. Each set of connecting parts consists of two connecting plates 21. A shelf 22 is rotatably connected between one end of the two connecting plates 21. Two fixed tubes 23 are fixedly connected to one side of the shelf 22. A movable rod 24 is slidably provided through the inner side of the fixed tube 23. The two ends of the two movable rods 24 are fixedly connected by a fixed plate 25 and an arc plate 26, respectively. A fixed block 27 is fixedly provided at the bottom of the fixed plate 25. Two springs 28 are provided between the shelf 22 and the fixed plate 25.

[0039] The arc plate 26, in conjunction with the soil-breaking cone 18, can rotate and scrape the irregular inner wall of the hole caused by the drill bit body 2 and the soil-breaking cone 18, making the inner wall of the borehole more regular and reducing the risk of hole collapse.

[0040] In this embodiment, the hollow tube 27 is penetrated by the fixed tube 23, the fixed plate 25 is penetrated by the movable rod 24, and the spring 28 is located on the periphery of the corresponding movable rod 24.

[0041] Spring 28 provides elastic support to the fixed plate 25.

[0042] In this embodiment, the base plate 20 is arranged in a "well" shape, one side of the fixing block 27 is inclined in the horizontal direction, the inner side of the hollow tube 6 is cross-shaped, and the base plate 15 and the hollow tube 6 are compatiblely matched.

[0043] The base plate 15 slides inside the hollow tube 6 under the action of the electric telescopic rod 12.

[0044] In this embodiment, a buffer structure 4 is provided on the inner side of the hollow tube 2 7 and the connecting tube 1 8. The buffer structure 4 includes several springs 29 and a base 30. The springs 29 are disposed between the bottom of the hollow tube 2 7 and the inner bottom surface of the connecting tube 1 8. The base 30 is slidably disposed on the inner side of the hollow tube 2 7. The base 30 is fixedly connected to the connecting tube 1 8 by four limiting rods 31. An electric push rod 32 is provided on the top of the base 30. A top plate 33 is fixedly disposed at one end of the electric push rod 32. Four inclined plates 34 are fixedly disposed at the bottom of the top plate 33. A pressure plate 35 is fixedly connected to one end of the inclined plate 34.

[0045] The buffer structure 4, together with the adjustment structure 3, can buffer the resistance received by the drill bit body 2, which can further improve the service life of the drill bit body 2. At the same time, under the action of spring 1 28, spring 2 29, pressure plate 35, and fixing block 27, the arc plate 26 can perform intermittent expansion and contraction movements. This is beneficial for the arc plate 26 to rotate and press the inner wall of the borehole after expansion under the action of the rotary drilling machine, so that the inner wall of the hole is compacted and the hole collapse is avoided.

[0046] In this embodiment, the hollow tube 2 7 is penetrated by the limiting rod 31, and the pressure plate 35 and the fixing block 27 are adaptively matched.

[0047] The pressure plate 35 moves up and down in coordination with the spring 28, which acts on the fixed block 27 to move horizontally left and right repeatedly.

[0048] In this embodiment, the pressure plate 35 consists of two protrusions and a connecting block.

[0049] The protrusion of the pressure plate 35 is in contact with the surface of the fixing block 27 in the initial state.

[0050] In this embodiment, a stop structure 5 is provided on the outside of the connecting pipe 8. The stop structure 5 includes two mounting plates 36. The mounting plates 36 are fixedly connected to the connecting pipe 8. An electric push rod 38 is provided on the top of the mounting plate 36. One end of the electric push rod 38 is fixedly connected to a limit plate 39. The limit plate 39 consists of two limit posts and a horizontal plate.

[0051] The stop structure 5, in conjunction with the buffer structure 4, allows the drill bit body 2 to perform resistance buffering or not buffering as needed. When the electric push rod 2 38 acts on the limit plate 39 and moves upward, the distance between the hollow tube 1 6 and the hollow tube 2 7 remains constant and does not move. When the electric push rod 2 38 acts on the limit plate 39 in the initial state, the distance between the hollow tube 1 6 and the hollow tube 2 7 changes continuously under the action of the spring 29 when the drill bit body 2 is subjected to resistance.

[0052] In this embodiment, four limiting tubes 37 are fixedly installed at the bottom of the hollow tube 2 7, and the limiting tubes 37 and the limiting posts of the limiting plate 39 are adaptively matched.

[0053] The limiting tube 37, together with the limiting plate 39, can restrict the position of the connecting tube 8. When the limiting post of the limiting plate 39 is inserted into the inside of the limiting tube 37, the drill bit body 2 loses its buffering effect.

[0054] In this embodiment, both bolt fastener 19 and bolt fastener 21 are composed of bolts and nuts.

[0055] Bolt fastener 19 serves to connect and fix connecting pipe 18 and hollow pipe 16, and bolt fastener 21 serves to connect and fix connecting pipe 210 and conveyor paddle 1.

[0056] It should be noted that this invention is a rotary drilling bit for coal mine engineering construction. Before use, the conveyor blade 1 is installed on the existing rotary drilling rig. The conveyor blade 1 is installed on the connecting pipe 10 using bolt fastener 2 11, and the connecting pipe 8 is installed on the hollow pipe 6 using bolt fastener 9. This will enable it to reach the operating conditions. The initial state is as follows: Figure 1 As shown;

[0057] When the rotary drilling rig is performing normal drilling operations, the conveyor blade 1 is perpendicular to the ground and the drill bit body 2 contacts the ground. The power unit of the rotary drilling rig then rotates the conveyor blade 1 and gradually lowers it. The drill bit body 2 and the ground-breaking cone 18 rotate to drill a hole. During this process, the drill bit body 2 experiences resistance, causing the hollow tube 6 and connecting tube 8 to slide towards the hollow tube 7. The spring 29 compresses the connecting tube 8, which moves the chassis 30 via the limit rod 31. The chassis 30 acts on the electric push rod 32 and the top plate 33 to move synchronously, ultimately causing the pressure plate 35 to press against the fixed block 27. Under the action of the pressure plate 35, the fixed block 27 moves the fixed plate 25 towards the arc plate 26. Since the fixed plate 25 is fixedly connected to the arc plate 26 via the movable rod 24, the arc plate 26 moves with the fixed block 27. As the spring 29 rebounds, the hollow tube 6 moves downwards, and the pressure plate 35 also moves downwards. The spring 28 loses pressure and acts on the fixed plate 25, causing the arc plate 26 to rebound. Under the action of the rotary drilling machine, the drill bit body 2 continues to penetrate deeper into the ground to perform rotary drilling. Under the action of force, the spring 29 continuously compresses and rebounds, which has a buffering effect on the drill bit body 2. At the same time, the pressure plate 35 continuously acts on the fixed block 27. Under the action of the spring 28, the fixed plate 25 causes the arc plate 26 to expand and contract at different times. During the continuous expansion and contraction, the arc plate 26 rotates and presses the inner wall of the hole created by the drill bit body 2 and the soil breaking cone 18, so that the inner wall is compacted under the pressure of the arc plate 26 to prevent collapse. Finally, the generated soil is transported out of the hole through the conveyor paddle 1.

[0058] When the rotary drilling rig is enlarging the hole, the electric telescopic rod 12 is activated, causing the fixed plate 13 to move downwards to the predetermined position and then stop. During this process, the fixed plate 13 moves outwards from the hollow tube 6 via the connecting plate 14 and the bottom plate 15. The bottom plate 15 moves synchronously with the bottom plate 17 and the breaking cone 18 via the guide rod 16 until the breaking cone 18 reaches the predetermined position. At this point, the electric push rod 32 is activated, causing the pressure plate 35 to move downwards, thus releasing the pressure plate 35 from restricting the position of the fixed block 27. Then, the electric telescopic rod 19 is activated, causing the bottom plate 20 to move downwards to the predetermined position and then stop. During this process, the bottom plate 20 moves outwards from the hollow tube 7 via the connecting plate 21 and the shelf 22. The rack 22 moves synchronously with the arc plate 26 through the fixed tube 23. At this time, the positions of the arc plate 26 and the soil-breaking cone 18 are matched. The previous conveyor paddle 1 is removed and a conveyor paddle 1 matching the position of the soil-breaking cone 18 is installed. Then, the pressure plate 35 is moved up to the position matching the fixed block 27 through the electric push rod 32. At this time, the rotary drilling machine acts on the conveyor paddle 1 to rotate and move down. During the process, the drill bit body 2 and the soil-breaking cone 18 rotate and drill as described above. Similarly, the drill bit body 2 is pressure buffered during the drilling process. At the same time, the inner wall of the hole is rotated and pressed through the arc plate 26. Finally, the generated soil is transported out of the hole through the conveyor paddle 1.

[0059] In addition, when the drill bit body 2 is not required to provide pressure buffering, the electric push rod 38 is activated to move the limiting plate 39 toward the limiting tube 37 until the limiting post of the limiting plate 39 is inserted into the inside of the limiting tube 37 and then stops. At this time, the drill bit body 2 will not move toward the hollow tube 7 when it is subjected to resistance, and the expansion of the arc plate 26 is also prohibited.

Claims

1. A rotary drilling rig bit for coal mine construction, comprising a conveyor paddle (1) and a drill bit body (2), characterized in that: An adjustment structure (3) is provided between the conveyor paddle (1) and the drill bit body (2); The adjustment structure (3) includes a hollow tube one (6), a hollow tube two (7), a connecting tube one (8), and a connecting tube two (10). The hollow tube one (6) is fixedly connected to the drill bit body (2), and the hollow tube one (6) is connected to the connecting tube one (8) by several bolt fasteners one (9). The hollow tube two (7) is slidably connected to the connecting tube one (8). The connecting tube two (10) is fixedly connected to the hollow tube two (7), and the connecting tube two (10) is connected to the conveyor paddle (1) by several bolt fasteners two (11). The hollow tube one (6) of the hollow tube one (6) An electric telescopic rod (12) is provided at the top, and one end of the electric telescopic rod (12) passes through the top of the hollow tube (6) and is fixedly connected to a fixed plate (13). The bottom of the fixed plate (13) is rotatably connected to four connecting plates (14), and one end of the connecting plate (14) is rotatably connected to a base plate (15). The base plate (15) is fixedly connected to a base plate (17) through several guide rods (16). Several soil-breaking cones (18) are fixedly provided on one side of the base plate (17). The hollow tube (6) is penetrated by the guide rods (16). The adjustment structure (3) also includes an electric telescopic rod two (19), which is set at the top of the hollow tube two (7). The electric telescopic rod two (19) passes through the top of the hollow tube two (7) and is fixedly connected to a base plate three (20). The bottom of the base plate three (20) is rotatably provided with four sets of connecting parts. Each set of connecting parts consists of two connecting plates two (21). A shelf (22) is rotatably connected between one end of the two connecting plates two (21). Two fixed tubes (23) are fixedly connected to one side of the shelf (22). A movable rod (24) is slidably provided through the inner side of the fixed tube (23). The two ends of the two movable rods (24) are fixedly connected by a fixed plate (25) and an arc plate (26) respectively. A fixed block (27) is fixedly provided at the bottom of the fixed plate (25). Two springs one (28) are provided between the shelf (22) and the fixed plate (25). The inner sides of the hollow tube 2 (7) and the connecting tube 1 (8) are provided with a buffer structure (4). The buffer structure (4) includes several springs 2 (29) and a base plate (30). The springs 2 (29) are located between the bottom of the hollow tube 2 (7) and the inner bottom surface of the connecting tube 1 (8). The base plate (30) is slidably located inside the hollow tube 2 (7). The base plate (30) is fixedly connected to the connecting tube 1 (8) by four limiting rods (31). The top of the base plate (30) is provided with an electric push rod 1 (32). One end of the electric push rod 1 (32) is fixedly provided with a top plate (33). The bottom of the top plate (33) is fixedly provided with four inclined plates (34). One end of the inclined plate (34) is fixedly connected with a pressure plate (35).

2. The rotary drilling bit for coal mine engineering construction according to claim 1, characterized in that: The hollow tube 2 (7) is penetrated by the fixed tube (23), the fixed plate (25) is penetrated by the movable rod (24), and the spring 1 (28) is located on the periphery of the corresponding movable rod (24).

3. The rotary drilling bit for coal mine engineering construction according to claim 1, characterized in that: The base plate three (20) is arranged in a "well" shape, one side of the fixing block (27) is inclined in the horizontal direction, the inner side of the hollow tube one (6) is cross-shaped, and the base plate one (15) and the hollow tube one (6) are compatiblely matched.

4. The rotary drilling bit for coal mine construction according to claim 1, characterized in that: The hollow tube 2 (7) is penetrated by the limiting rod (31), and the pressure plate (35) and the fixing block (27) are adaptively matched.

5. A rotary drilling bit for coal mine construction according to claim 1, characterized in that: The pressure plate (35) consists of two protrusions and a connecting block.

6. A rotary drilling bit for coal mine construction according to claim 1, characterized in that: The outside of the connecting pipe (8) is provided with a stop structure (5). The stop structure (5) includes two mounting plates (36). The mounting plates (36) and the connecting pipe (8) are fixedly connected. The top of the mounting plate (36) is provided with an electric push rod (38). One end of the electric push rod (38) is fixedly connected to a limit plate (39). The limit plate (39) consists of two limit posts and a horizontal plate.

7. A rotary drilling bit for coal mine construction according to claim 6, characterized in that: The bottom of the hollow tube 2 (7) is fixedly provided with four limiting tubes (37), and the limiting tubes (37) and the limiting posts of the limiting plate (39) are adaptively matched.

8. A rotary drilling bit for coal mine construction according to claim 1, characterized in that: Both bolt fastener one (9) and bolt fastener two (11) are composed of bolts and nuts.

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