A core bit

Abstract

The present invention discloses a core drill bit, belonging to the technical field of core drills, which includes a hollow drill barrel with an opening at one end. A number of ramp grooves with a sloping bottom surface are circumferentially arranged on the inner wall of the hollow drill barrel. A rolling body that can roll from the bottom end of the slope surface towards the top end of the slope surface and gradually change from hidden to exposed is arranged in the ramp groove. The rolling body is held at the top end of the slope surface of the ramp groove through an elastic reset mechanism. The rolling body includes a circumferential cutting disc that can be pushed by the core block as the hollow drill barrel rotates and a clamping column that can clamp the core block in the exposed state. The circumferential cutting disc is coaxially fixed to one end of the clamping column close to the opening. The ramp groove and the rolling body cooperate with each other to form the characteristic of "loosening when rotating forward and tightening when rotating backward". When rotating forward, the clamping column and the circumferential cutting disc will be hidden in the ramp groove under the push of the core block, without affecting normal core extraction. When rotating backward, the circumferential cutting disc and the clamping column will be exposed in sequence, gradually realizing the functions of "circumferential cutting - clamping - twisting off", ensuring that the core block breaks and detaches from the parent body relatively completely.

Description

Technical Field

[0001] The present invention relates to the technical field of core drills, and particularly to a core drill bit. Background Art

[0002] Core drill bits are mainly tools for drilling and sampling products such as rocks or concrete. However, existing core drill bits generally have the problem of "drilling in but not taking out", that is, under the drive of the motor of the core drilling machine, the core drill bit can only cut an annular groove on the parent body, but the core block in the annular groove cannot be taken out together with the core drill bit because its root is connected to the parent body. Therefore, a stick needs to be inserted into the gap between the core block and the parent body to pry it off before it can be taken out, resulting in a significant reduction in construction efficiency. For this reason, a utility model patent with the patent number "202122390289.0" and the patent name "A hydraulic core drill bit" discloses a core drill bit that can break the core block after drilling. It includes a cylinder body and a splitter. An accommodation cavity is arranged in the cylinder body along its axial direction. An opening communicating with the accommodation cavity is arranged at the bottom of the cylinder body. The splitter is arranged on the side wall of the cylinder body. The splitter includes a splitter ejector post, and the splitter ejector post can expand and contract radially along the accommodation cavity. After grooving is completed, the splitter ejector post extends out to break the root of the core block, so that the core block can be separated from the parent body. Then, by clamping the core with the splitter ejector post, the core can be taken out together with the core drill bit. However, in the above patent, since rocks and concrete are brittle materials, the method of using the splitter ejector post to squeeze and break the root of the core block easily causes the entire core block to crack from the inside out. When the splitter ejector post presses tightly against the core block later, it is even easier to squeeze and break the cracked core block into countless small pieces, unable to maintain good integrity of the core, which is not conducive to observation and research. In addition, if there are cracks, holes and other damages inside the rock and concrete itself, whether it is the existing core drill bit or the mechanical vibration during drilling in the above patent is also likely to cause the core to break and be damaged during forming. Summary of the Invention

[0003] The object of the present invention is to solve the above technical problems and provide a core drill bit. The ramp groove on the inner wall of the hollow drill cylinder and the rolling body cooperate with each other to form a "loosening when rotating forward and tightening when rotating backward" characteristic. When taking core by rotating forward, the clamping posts and the circumferential cutting disc on the rolling body will be hidden in the ramp groove under the push of the core block, without affecting normal core taking. When the hollow drill cylinder is rotated backward, the circumferential cutting disc and the clamping posts will be successively exposed from the ramp groove under the push of the elastic reset mechanism and the core block, gradually realizing the functions of "circumferential cutting - clamping - twisting off" the core block, ensuring the function of the core block breaking from the root and separating from the parent body relatively intact.

[0004] To achieve the above object, the present invention provides the following solutions: The present invention discloses a core drill bit, which includes a hollow drill barrel with an opening at one end. A number of ramp grooves with a sloping bottom surface are circumferentially arranged on the inner wall of the hollow drill barrel. A rolling body capable of rolling from the bottom end of the slope surface towards the top end of the slope surface and gradually transitioning from a hidden state to a revealed state during the rolling process is provided in the ramp groove. The rolling body is parallel to the axis of the hollow drill barrel and is held at the top end of the slope surface of the ramp groove by an elastic reset mechanism. The rolling body includes a circumferential cutting disc that can be pushed by a core block as the hollow drill barrel rotates and a clamping column that can clamp the core block in the revealed state. The circumferential cutting disc is coaxially fixed to one end of the clamping column close to the opening.

[0005] Preferably, guiding grooves with the same inclination direction and inclination degree as the slope surface are provided at both ends of the ramp groove extending along the axis of the hollow drill barrel. Rolling shafts that are coaxially fixed to both ends of the clamping column and are rollingly connected in the guiding grooves are provided.

[0006] Preferably, the elastic reset mechanism includes a reset compression spring provided between the bottom end of the slope surface of the guiding groove and the rolling shaft.

[0007] Preferably, a pushing ball that abuts against the rolling shaft is fixed to the end of the reset compression spring, and the pushing ball is slidably connected in the guiding groove.

[0008] Preferably, the ramp groove includes a first groove section and a second groove section that are respectively in constant contact with the clamping column and the circumferential cutting disc.

[0009] Preferably, the cross-section of the circumferential cutting tool is elliptical.

[0010] Preferably, the surface of the clamping column is a rough surface.

[0011] Preferably, a telescopic ejector rod is provided on the inner wall of the hollow drill barrel at the end far from the opening. The end of the telescopic ejector rod is rotatably connected to a top head for pressing tightly against the core block. A compression spring that constantly presses tightly against the top head is sleeved on the telescopic ejector rod.

[0012] Preferably, anti-slip teeth are provided on the pressing surface of the top head for pressing tightly against the core block.

[0013] Preferably, the top head is rotatably connected to the telescopic ejector rod through a bearing.

[0014] The present invention has achieved the following technical effects compared with the prior art:

[0015] 1. In the core bit of the present invention, the ramp grooves on the inner wall of the hollow drill barrel and the rolling elements cooperate with each other to form the "loosen when rotating forward and tighten when rotating backward" characteristic. When taking a core by rotating forward, the clamping columns and the circumferential cutting disks on the rolling elements will be hidden in the ramp grooves under the push of the core block, thus not affecting normal core taking. When it is necessary to break the core block, just reverse the hollow drill barrel. The clamping columns and the circumferential cutting disks will be exposed from the ramp grooves under the push of the elastic reset mechanism and the core block. The circumferential cutting disk will first contact the root of the core block. Due to its small contact surface and being relatively "sharp", it will produce a "circumferential cutting" effect on the surface of the core block, performing a circumferential cut on the end of the core block to create a weak zone on the core block. For brittle materials, the weak position is the fracture position. Subsequently, the clamping columns contact the core block and clamp it. As the hollow drill barrel rotates in reverse, the core block is thus twisted off from the weak position, realizing the functions of "circumferential cutting - clamping - twisting off" the core block, and ensuring the function of the core block being broken and separated from the parent body relatively intact at the root.

[0016] 2. In the core bit of the present invention, a push rod device is added inside the hollow drill barrel. The telescopic push rod and the compression spring cooperate to always tightly push against the core block, applying an axial pressure to the core block to increase the friction between the fragments inside the broken core block, thereby effectively alleviating the fragmentation of the core. Since the push head and the telescopic push rod are rotatably connected, the telescopic push rod is a device that can only transmit axial pressure and cannot transmit rotational torque, and will not rotate together with the hollow drill barrel. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 Schematic structural diagram of a core drill equipped with the present core bit;

[0019] Figure 2 Schematic internal structure diagram when the core bit is performing circumferential cutting and clamping;

[0020] Figure 3 Partial enlarged view of the internal structure of the core bit;

[0021] Figure 4 Cross-sectional view of the core bit from the bottom view angle;

[0022] Figure 5 Front sectional view when the rolling element is at the bottom of the slope;

[0023] Figure 6 Front sectional view when the rolling element is at the top of the slope;

[0024] Figure 7 Schematic diagram of the guiding groove when the rolling element is at the bottom of the slope;

[0025] Figure 8 Schematic diagram of the guiding groove when the rolling element is at the top of the slope;

[0026] Figure 9 Schematic diagram of the slope groove when the rolling element is at the bottom of the slope;

[0027] Figure 10 Schematic diagram of the slope groove when the rolling element is at the top of the slope;

[0028] Figure 11 Schematic diagram of structures such as the telescopic ejector rod inside the hollow drill barrel.

[0029] Explanation of reference numerals: 1, hollow drill barrel; 2, rolling element; 3, clamping column; 4, circumferential cutting disc; 5, rolling shaft; 6, slope groove; 7, guiding groove; 8, return compression spring; 9, pushing ball; 10, first groove section; 11, second groove section; 12, telescopic ejector rod; 13, ejector head; 14, pressing spring; 15, anti-slip teeth; 16, bi-directional bearing; 17, drive motor; 18, core block. Specific implementation manners

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0031] This embodiment provides a core drill bit, as Figures 1 to 11As shown in the figure, it includes a hollow drill barrel 1. One end of the hollow drill barrel 1 is open, and the other end can be installed on the output shaft of the driving motor 17 of the core sampler, so that the hollow drill barrel 1 can be driven by the driving motor 17 to rotate forward or backward. A number of ramp grooves 6 are circumferentially arranged on the inner wall of the hollow drill barrel 1. The bottom of the ramp groove 6 is a slope surface. Because the bottom of the ramp groove 6 is a slope surface, the groove depth at the bottom end of the groove is deeper than that at the top end of the slope. A rolling body 2 is arranged in the ramp groove 6. The rolling body 2 can roll from the bottom end of the slope at the bottom of the ramp groove 6 to the top end of the slope, or from the top end of the slope to the bottom end of the slope. The groove depth at the bottom end is greater than the diameter of the rolling body 2, and at the same time, the groove depth at the top end is less than the diameter of the rolling body 2, so that the rolling body 2 originally hidden at the bottom end of the slope gradually reveals itself during the rolling process to the top end of the slope. The rolling body 2 is parallel to the axis of the hollow drill barrel 1 and is held at the top end of the slope surface of the ramp groove 6 through an elastic reset mechanism. That is, before the hollow drill barrel 1 is used, the rolling body 2 is in a revealed state. The rolling body 2 includes a clamping column 3 and a circumferential cutting disc 4. The circumferential cutting disc 4 is coaxially fixed at one end of the clamping column 3 close to the opening. When the hollow drill barrel 1 rotates forward for core drilling, under the friction force of the core block 18, the circumferential cutting disc 4 will overcome the elastic force of the elastic reset mechanism, and then drive the clamping column 3 to roll from the top end of the slope surface of the ramp groove 6 to the bottom end, so that the circumferential cutting disc 4 and the clamping column 3 are hidden in the ramp groove 6. When the hollow drill barrel 1 rotates reversely, under the action of the elastic reset mechanism and the friction force of the core block 18, the circumferential cutting disc 4 will drive the clamping column 3 to roll from the bottom end of the slope surface of the ramp groove 6 to the top end, so that the circumferential cutting disc 4 and the clamping column 3 will protrude from the ramp groove 6 to reach the revealed state. At this time, the revealed circumferential cutting disc 4 will rotate with the hollow drill barrel 1 to cut the root of the core block 18, cutting out a circumferential cutting seam, so as to achieve the circumferential cutting effect and reduce the connection between the root of the core block 18 and the parent body. Then the revealed clamping column 3 will clamp the core block 18 and twist the core block 18 as the hollow drill barrel 1 rotates reversely. Because of the existence of the circumferential cutting seam, the core block 18 will be disconnected from the parent body at the circumferential cutting seam, and then lift the hollow drill barrel 1 in the reverse rotation state, and the core block 18 can be taken out.

[0032] Working process:

[0033] First, install the hollow drill cylinder 1 onto the drive motor 17 of the core sampler; then, adjust the height of the drive motor 17 so that the hollow drill cylinder 1 is aligned with the position where coring is to be performed; then, start the drive motor 17 to make the hollow drill cylinder 1 rotate forward, and at the same time, move the drive motor 17 as a whole downward for drilling. During the drilling process, the circumferential cutting disc 4 is pushed by the core block 18, and the circumferential cutting disc 4 drives the clamping column 3 to move from the top of the slope at the bottom of the slope groove 6 to the bottom of the slope. The reset elastic mechanism will be gradually compressed until the circumferential cutting disc 4 is hidden in the bottom of the slope of the slope groove 6 and "rotates in place". After drilling in place, stop the drive motor 17; then, start the drive motor 17 again to make the hollow drill cylinder 1 rotate in reverse. At this time, under the pushing force of the reset elastic force of the reset elastic mechanism on the rolling body 2 and the pushing force of the friction of the circumferential cutting disc 4 on the core block 18, the circumferential cutting disc 4 will drive the clamping column 3 to move from the bottom of the slope at the bottom of the slope groove 6 to the top of the slope, and the circumferential cutting disc 4 and the clamping column 3 will gradually be revealed. The circumferential cutting disc 4 performs circumferential cutting on the root of the core block 18, and the clamping column 3 clamps the core block 18 and breaks it off from the root to separate it from the parent body; finally, while keeping the hollow drill cylinder 1 rotating in reverse, move the drive motor 17 upward, thereby lifting the hollow drill cylinder 1. Under the clamping action of the clamping column 3 and the supporting action of the circumferential cutting disc 4 on the bottom of the core block 18, the core block 18 is lifted out of the parent body to achieve coring.

[0034] In this embodiment, as Figures 1 to 11 shown, guiding grooves 7 are provided at both ends of the slope groove 6 extending along the axis of the hollow drill cylinder 1. The guiding grooves 7 are elongated grooves arranged obliquely. The inclination direction and inclination degree of the guiding grooves 7 are the same as the inclination direction and slope of the bottom of the slope groove 6. Rolling shafts 5 are coaxially fixed at both ends of the clamping column 3, and the rolling shafts 5 are in rolling connection with the guiding grooves 7. Under the combined action of the guiding grooves 7 and the rolling shafts 5, on the one hand, it can guide the movement of the clamping column 3 and the circumferential cutting disc 4, and on the other hand, it can keep the clamping column 3 and the circumferential cutting disc 4 within the slope groove 6.

[0035] In this embodiment, as Figures 1 to 11 shown, the elastic reset mechanism includes a reset compression spring 8. The reset compression spring 8 is arranged between the top of the slope of the guiding groove 7 and the rolling shaft 5. One end of the reset compression spring 8 is fixedly connected to the top of the slope of the guiding groove 7, and the other end abuts against the rolling shaft 5.

[0036] Furthermore, in order to prevent the reset compression spring 8 from being wound into the rolling shaft 5, in this embodiment, as Figures 1 to 11 shown, a pushing ball 9 is fixed at the end of the reset compression spring 8. The pushing ball 9 is in sliding connection with the guiding groove 7 and always abuts against the rolling shaft 5. The diameter of the pushing ball 9 matches the width of the guiding groove 7.

[0037] In this embodiment, as Figures 1 to 11As shown, the ramp groove 6 includes a first groove section 10 and a second groove section 11. The groove depths of both the first groove section 10 and the second groove section 11 gradually increase from the bottom end of the slope to the top end of the slope, so as to be in contact with the clamping column 3 and the circumferential cutting disc 4 at all times, thereby providing sufficient supporting force for the clamping column 3 and the circumferential cutting disc 4 when the clamping column 3 and the circumferential cutting disc 4 contact the core block 18, so that the clamping column 3 can clamp the core block 18 and the circumferential cutting disc 4 can effectively cut into the core block 18. The overall groove depth of the second groove section 11 is greater than that of the first groove section 10 to ensure that the second groove section 11 can effectively accommodate the circumferential cutting disc 4 with a diameter larger than that of the clamping column 3.

[0038] In this embodiment, as Figures 1 to 11 shown, the cross-section of the circumferential cutting knife 4 is oval, and the end faces on both sides of the circumferential cutting knife 4 with an oval cross-section are arc surfaces, which is beneficial for the core block 18 to push the circumferential cutting knife 4 to both sides along the arc surface during the initial core taking, so as to push the circumferential cutting knife 4 into the second groove section 11, and the circumferential cutting knife 4 will not be damaged by being pressed against the end of the core block 18.

[0039] In this embodiment, as Figures 1 to 11 shown, the surface of the clamping column 3 is a rough surface, which can increase the friction with the core block 18, ensure that the core block 18 can be clamped, and avoid the problem of "slipping", so that the core block 18 does not break away from the clamping column 3 during core taking. Preferably, the bottom of the first groove section 10 can also be set as a rough surface, so as to increase the friction between the first groove section 10 and the clamping column 3, thereby avoiding the problem of "slipping" between the clamping column 3 and the first groove section 10.

[0040] In this embodiment, as Figures 1 to 11 shown, a telescopic ejector rod 12 is provided on the inner wall of the end of the hollow drill cylinder 1 far away from the opening. The end of the telescopic ejector rod 12 is rotatably connected with a top head 13 for pressing the core block 18, and a compression spring 14 for pressing the top head 13 at all times is sleeved on the telescopic ejector rod 12. The length of the telescopic ejector rod 12 will change according to the depth of the hollow drill cylinder 1. The compression spring 14 can ensure that the top head 13 presses the core block 18 at all times, so as to apply an axial pressure to the core block 18 and increase the friction between the fragments inside the core block 18 to effectively relieve the fragmentation of the core block 18.

[0041] Furthermore, in this embodiment, as Figures 1 to 11 shown, anti-slip teeth 15 are provided on the pressing surface of the top head 13 for pressing the core block, so as to increase the friction between the top head 13 and the core block 18, avoid the "slipping" phenomenon, and ensure the pressing effect.

[0042] Furthermore, in this embodiment, as Figures 1 to 11 shown, the top head 13 is rotatably connected with the telescopic ejector rod 12 through a bearing. The bearing adopts a two-way bearing 16, and the two-way bearing 16 only transmits axial force and does not transmit torsional force.

[0043] Specific examples are used in the invention to illustrate the principles and implementation manners of the invention. The description of the above embodiments is only used to help understand the method and its core idea of the invention; at the same time, for those of ordinary skill in the art, according to the idea of the invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the invention.

Claims

1. A core bit, characterized in that, it includes a hollow drill barrel with an opening at one end. A number of ramp grooves with a sloping bottom surface are circumferentially arranged on the inner wall of the hollow drill barrel. A rolling body that can roll from the bottom end of the slope surface towards the top end of the slope surface and gradually change from being hidden to being exposed during the rolling process is provided in the ramp groove. The rolling body is parallel to the axis of the hollow drill barrel and is held at the top end of the slope surface of the ramp groove by an elastic reset mechanism. The rolling body includes a circumferential cutting disc that can be pushed by a core block as the hollow drill barrel rotates and a clamping column that can clamp the core block in the exposed state. The circumferential cutting disc is coaxially fixed to one end of the clamping column close to the opening; both ends of the ramp groove extending along the axis of the hollow drill barrel are provided with guide grooves with the same inclination direction and inclination as the slope surface. Rolling shafts that are coaxially fixed at both ends of the clamping column and are in rolling connection in the guide grooves are provided; an expansion and contraction push rod is provided on the inner wall of the hollow drill barrel at the end away from the opening. The end of the expansion and contraction push rod is rotatably connected to a top head for tightly pressing the core block. A compression spring that always tightly presses the top head is sleeved on the expansion and contraction push rod.

2. The core bit according to claim 1, characterized in that, the elastic reset mechanism includes a reset compression spring provided between the bottom end of the slope surface of the guide groove and the rolling shaft.

3. The core bit according to claim 2, characterized in that, a pushing ball that abuts against the rolling shaft is fixed at the end of the reset compression spring. The pushing ball is slidably connected in the guide groove.

4. The core bit according to claim 1, characterized in that, the ramp groove includes a first groove section and a second groove section that are respectively in constant contact with the clamping column and the circumferential cutting disc.

5. The core bit according to claim 4, characterized in that, the cross-section of the circumferential cutting disc is elliptical.

6. The core bit according to claim 5, characterized in that, the surface of the clamping column is a rough surface.

7. The core bit according to claim 1, characterized in that, anti-slip teeth are provided on the top surface of the top head for tightly pressing the core block.

8. The core bit according to claim 7, characterized in that, the top head is rotatably connected to the expansion and contraction push rod through a bearing.

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