Involute bottom anchor bolt

Abstract

The utility model discloses an involute bottom anchor bolt which comprises an inner conical rod, an involute pipe and an external bolt, wherein the involute pipe is arranged on the inner conical rod and can rotate in the same direction with the inner conical rod at different rotating speeds, and the external bolt is connected to an external thread section of the inner conical rod through a fixed connecting pipe so as to fix an object. The inner conical rod and the involute pipe are in threaded connection and rotate in the same direction at different speeds, so that the involute cutting part at the front end of the involute pipe is gradually expanded in a rotating mode to cut a hole wall, a conical hole is formed to achieve anchoring, the installation process of the anchor bolt is simplified, taper fit is enhanced, and the anchoring quality is improved. The falling or sliding-out failure caused by the vibration of a fixed object can be avoided; the anchor bolt sinks into a base by arranging the fixed connecting pipe, so that a fixed object is conveniently installed and fixed, and meanwhile potential safety hazards existing in a fixed point position are avoided; the involute bottom anchor bolt is simple in structure and is provided with an expansion in-place immediate stop structure and a sunken mounting structure, and the applicability of the anchor bolt is improved.

Description

Technical Field

[0001] This utility model relates to an anchor bolt, specifically a non-expansion involute anchor bolt. Background Technology

[0002] Expansion anchors, or simply expansion bolts, are components that utilize the relative movement of the cone on the cone rod and the expansion plate to cause the expansion plate to be pressed against the inner wall of the hole. The friction between the pressing surfaces generates frictional force, which is used to temporarily fix the object.

[0003] Existing expansion anchors require secondary drilling using both straight-hole and reaming drill bits during installation, resulting in complex procedures, poor fit of the conical hole surface, and high installation costs. Furthermore, when anchored to the base, the conical rod of the existing expansion anchor often protrudes from the base surface, creating safety hazards or requiring later cutting. Additionally, it is necessary to raise the object to align with the conical rod to meet the connection requirements, which is inconvenient and costly when using large or heavy equipment.

[0004] Furthermore, the existing expansion anchors are installed by hammering or impacting, which makes it difficult to ensure the installation effect. Firstly, the installation may not be in place, and secondly, the expansion stress of the anchor may be too great, causing the concrete to crack and resulting in secondary failure during use. Therefore, multiple periodic maintenance and inspection of the tightening of the nuts are required. Summary of the Invention

[0005] To overcome the above-mentioned defects, this utility model provides an involute bottom anchor bolt, which abandons the existing fixing methods of lateral compression such as hammering, pulling, and impact expansion. Instead, it uses a special tool to rotate at high speed, so that the anchor bolt cuts the hole wall in an involute manner to form a conical hole. This allows the involute tube to be fixed to the hole wall with a conical surface without difference, so there is no need for secondary conical hole expansion. At the same time, this utility model changes the traditional method of fixing objects. It uses a fixed connecting tube to sink the anchoring end of the anchor bolt into the base, eliminating the safety hazard of the screw protruding from the ground and facilitating the installation and fixing of objects.

[0006] The technical solution adopted by this utility model to solve its technical problem is: to provide an involute anchor bolt, comprising:

[0007] An inner tapered rod includes a rod portion and an expansion portion disposed at the front end of the rod portion. The outer peripheral wall of the rod portion is provided with an external threaded section and an external smooth surface section along its longitudinal axis. The expansion portion has an expansion section that expands conically to the maximum diameter at a first conical angle towards the front end along the axial direction of the rod portion.

[0008] An involute tube is rotatably mounted on the inner cone rod and can rotate in the same direction as the inner cone rod at different speeds. The involute tube includes a connecting portion and an involute cutting portion located at the front end of the connecting portion. The inner peripheral wall of the connecting portion is provided with an internal threaded section that engages with the external threaded section of the rod. The involute cutting portion has multiple cutting segments that can be gradually expanded by the expansion section when the involute tube rotates and feeds towards the front end relative to the inner cone rod along the longitudinal axis, and cut the borehole wall to form a tapered hole.

[0009] External bolts are connected to the external threaded section of the inner tapered rod via a fixed connecting tube to fix the object.

[0010] As a further improvement of this utility model, the rod portion of the inner cone rod has a cylindrical structure, and a tool interface is provided at its rear end for mounting the tool at its rear end in a shape lock and in an anti-rotation manner.

[0011] The external threaded section of the rod includes a rear external threaded section and a front external threaded section arranged from back to front along the longitudinal axis; the smooth surface section of the rod includes a rear smooth surface section disposed between the rear external threaded section and the front external threaded section, and a front smooth surface section disposed between the front external threaded section and the expansion portion;

[0012] The rear external thread section extends rearward from the rear external smooth section along the longitudinal axis to the rear end of the inner tapered rod.

[0013] As a further improvement of this utility model, the involute tube is a cylindrical tubular structure coaxially arranged with the inner conical rod, and it is also provided with a tool connection port for mounting the tool on its rear end in a shape-locking anti-rotation manner.

[0014] The internal thread segment is provided on the inner peripheral wall of the connecting part, and the internal thread segment is configured to include:

[0015] The rear internal thread section is provided at one end near the tool connection port and can engage with the rear external thread section.

[0016] The front internal thread section is provided at one end near the expansion portion and can engage with the front external thread section.

[0017] As a further improvement of this utility model, an inner smooth surface section is formed on the inner peripheral wall of the connecting part between the rear internal thread section and the front internal thread section. When the rear internal thread section moves to the rear outer smooth surface section of the rod and the front internal thread section moves to the front outer smooth surface section of the rod, the inner cone rod no longer feeds to the rear end. At this time, the involute tube and the inner cone rod are in a non-meshing connection state.

[0018] As a further improvement of this utility model, the involute cutting section is cantilevered and arranged at the front end of the involute tube through an annular section;

[0019] The cutting segments are provided in multiples, which are separated from each other by slits along the circumferential direction and connected to each other by the annular section, and the wall thickness of the annular section is less than the wall thickness of the involute cutting part.

[0020] As a further improvement of this utility model, the front end of the expansion section of the expansion part is connected to an auxiliary section through an arc-shaped part. The auxiliary section is a cylindrical structure formed by extending along the longitudinal axis from the maximum diameter of the expansion section to the front end.

[0021] As a further improvement of this utility model, the angle between the first cone angle and the longitudinal axis is in the range of 20° to 30°; the thickness dimension of the auxiliary section in the longitudinal direction is smaller than the thickness dimension of the expansion section in the longitudinal direction.

[0022] As a further improvement of this utility model, the involute tube is made of cemented carbide.

[0023] As a further improvement of this utility model, the surface of the cutting segment is coated with diamond grit by an electroplating process.

[0024] As a further improvement of this utility model, the fixed connecting tube is a cylindrical tubular structure, and its outer diameter is consistent with the maximum diameter of the inner conical rod.

[0025] The inner circumferential wall of the fixed connecting pipe is provided with a first connecting section that engages with the rear external thread section of the rod, a second connecting section for fixing and connecting external bolts, and a smooth extension section between the first connecting section and the second connecting section.

[0026] The beneficial effects of this utility model are:

[0027] ① By setting the inner cone rod and the involute tube to be threadedly connected and rotating in the same direction but at different speeds, the involute cutting part at the front end of the involute tube gradually expands to cut the hole wall, forming a tapered hole for anchoring. This simplifies the installation process of the anchor bolt, strengthens the tapered fit, and prevents it from falling off or slipping out due to vibration of the fixed object; ② By setting the connection between the inner cone rod and the involute tube to a multi-segment threaded connection, the involute tube feeding process is stabilized, and expansion can be automatically stopped when expansion is complete, effectively protecting the safety and reliability of the driving tool and the base; ③ By setting a fixed connecting pipe, the anchor bolt is sunk into the base, which facilitates the installation and fixation of the fixed object while avoiding the safety hazards of the fixing point; ④ The involute bottom anchor bolt of this utility model has a simple structure and has a structure that stops expansion when it is in place and a sunken installation structure, which improves the applicability of the anchor bolt. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the anchor bolt of this utility model;

[0029] Figure 2 This is an exploded structural diagram of the inner cone rod and involute tube of this utility model;

[0030] Figure 3 This is a cross-sectional structural diagram of the involute tube and the fixed connecting tube of this utility model;

[0031] Figure 4 This is a schematic diagram showing the usage state of this utility model.

[0032] Referring to the accompanying drawings, the following explanations are provided:

[0033] 1. Internal tapered rod; 11. Rod section; 111. Tool interface; 112. Rear external thread section; 113. Front external thread section; 114. Rear smooth surface section; 115. Front smooth surface section; 12. Expansion section; 121. Expansion zone; 122. Arc-shaped section; 123. Auxiliary zone; 2. Involute tube; 21. Connecting part; 211. Rear internal thread section; 212. Front internal thread section; 213. Smooth surface section; 22. Involute cutting part; 221. Cutting segment; 222. Slit; 23. Tool connection port; 24. Annular zone; 3. External bolt; 4. Fixed connecting tube; 41. First connecting zone; 42. Second connecting zone; 43. Extension zone; α. First cone angle; 5. Drill hole; D. Maximum diameter. Detailed Implementation

[0034] The preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[0035] See Figures 1 to 3 This utility model provides an embodiment of an involute bottom anchor bolt, used to anchor an object in a fixed base made of concrete.

[0036] The involute anchor bolt provided in this embodiment includes an inner cone rod 1 and a fixed connecting tube 4 disposed at the rear end of the inner cone rod 1. The involute tube 2 is rotatably mounted on the inner cone rod 1, and an external bolt 3 for fixing an object is mounted on the fixed connecting tube 4. This allows the entire structure of the anchor bolt to sink to the base surface, facilitating the fixed installation of the object. Furthermore, in this embodiment, the longitudinal length of the pre-drilled straight hole in the base is greater than the overall longitudinal length of the inner cone rod 1 after it mates with the fixed connecting tube 4. Figure 4 As shown, the space reserved at the front end of the inner cone rod 1 in the straight hole is used to receive concrete fragments generated by the base during the expansion and cutting of the inner wall of the straight hole by the involute tube 2.

[0037] In this embodiment, the involute tube 2 and the inner tapered rod 1 are connected by a movable connection. During operation, a differential speed tool drives the inner tapered rod 1 and the involute tube 2 to rotate around the same axis (longitudinal axis) at different speeds. Conversely, the inner tapered rod 1 moves rearward during operation, while the involute tube 2 remains stationary along its longitudinal axis, cutting the hole wall in place to form a tapered hole, thereby ensuring the accuracy of the anchoring depth to a certain extent.

[0038] Specifically, the inner tapered rod 1 includes a rod portion 11 and an expansion portion 12 located at the front end of the rod portion 11. The outer peripheral wall of the rod portion 11 is provided with an external thread section and an external smooth surface section along its longitudinal axis. The expansion portion 12 has an expansion section 121 that expands conically to the maximum diameter D at a first conical angle α towards the front end along the axial direction of the rod portion 11. The involute tube 2 includes a connecting portion 21 and an involute cutting portion 22 located at the front end of the connecting portion 21. The inner peripheral wall of the connecting portion 21 is provided with an internal thread section that meshes with the external thread section of the rod portion 11. The involute cutting portion 22 has multiple cutting segments 221, which can be gradually expanded by the expansion section 121 when the inner tapered rod 1 rotates and feeds towards the rear end along the longitudinal axis, so as to realize the cutting expansion of the hole wall, that is, the tapered hole expansion operation.

[0039] Conveniently, the involute tube 2 and the inner cone rod 1 are connected by threads. Under the action of a special differential tool, the inner cone rod 1 and the involute tube 2 are driven to rotate at different speeds. The speed of the inner cone rod 1 is set to be small and the speed of the involute tube 2 is set to be large. The threaded connection allows the inner cone rod 1 to be fed steadily to the rear end, which can prevent the rotation axis of the involute tube 2 from deviating from the longitudinal axis. This ensures that the cutting section 221 at the front end of the involute tube 2 is gradually expanded by the expansion section 121 and stably cuts the hole wall to form a tapered enlarged hole inside the straight hole. At the same time, the expansion part 12 of the inner cone rod 1 moves to the rear end and enters the expansion space formed by the cutting section 221, and is stopped by the connecting part 21 to realize the fixation of the anchor bolt.

[0040] In this embodiment, to facilitate the connection of the differential tool, the rod portion 11 of the inner cone rod 1 has a cylindrical structure, and its rear end is provided with a tool interface 111 for connecting to one drive shaft of the differential tool through a shape lock and anti-rotation. The involute tube 2 is a cylindrical tubular structure coaxial with the inner cone rod 1, and its rear end is also provided with a tool connection port 23 for connecting to another drive shaft of the differential tool through a shape lock and anti-rotation. This allows the inner cone rod 1 and the involute tube 2 to be rotated by the tool.

[0041] Furthermore, since most of the straight holes on the base are blind holes, to a certain extent, whether the cutting segment 221 of the involute tube 2 has expanded to the correct position is affected by the torque of the differential tool or the randomness of the installer. Therefore, at the beginning of the anchoring operation, it is impossible to determine whether the involute tube has expanded too much, which may damage the differential tool; or the continuous rotation of the involute tube 2 may cause the differential tool to overload. Therefore, this embodiment has a foolproof design for the threaded connection on the inner cone rod 1 and the involute tube 2.

[0042] Specifically, the external threaded section of the rod 11 includes a rear external threaded section 112 and a front external threaded section 113 arranged from rear to front along the longitudinal axis; the smooth outer surface section of the rod 11 includes a rear smooth outer surface section 114 disposed between the rear external threaded section 112 and the front external threaded section 113, and a front smooth outer surface section 115 disposed between the front external threaded section 113 and the expansion portion 12. The rear external threaded section 112 extends rearward from the rear smooth outer surface section 114 along the longitudinal axis to the rear end of the inner tapered rod 1 to achieve connection with the fixed connecting tube 4.

[0043] Correspondingly, the inner peripheral wall of the connecting part 21 is provided with an internal thread section, which is configured to include a rear internal thread section 211 provided at one end near the tool connection port 23 and capable of engaging with the rear external thread section 112; and a front internal thread section 212 provided at one end near the expansion part 12 and capable of engaging with the front external thread section 113. An inner smooth surface section 213 is formed on the inner peripheral wall of the connecting part 21 between the rear internal thread section 211 and the front internal thread section 212. That is, this embodiment adopts a two-stage threaded connection. When the rear internal thread section 211 moves to the rear external smooth surface section 114 of the rod part 11 and the front internal thread section 212 moves to the front external smooth surface section 115 of the rod part 11, the involute tube 2 loses its threaded connection with the inner cone rod 1, so that the inner cone rod will no longer feed to the rear end (i.e., it will idle under the drive of the tool), thereby ensuring the safety of the driving tool and the base.

[0044] Furthermore, the involute cutting section 22 is cantilevered at the front end of the involute tube 2 via an annular section 24. In this embodiment, there are six cutting sections 221, which are spaced apart from each other along the circumferential direction by slits 222 and connected to each other by annular sections 24. The wall thickness of the annular section 24 is less than the wall thickness of the involute cutting section 22, so that when the cutting section 221 is gradually opened, the thinner annular section 24 can reduce the stress generated by bending. In addition, this structure can also ensure that the involute cutting section 22 forms a complete tapered cutting surface in its circumferential direction when rotating, so as to realize the tapered hole expansion operation of the anchor hole on the base.

[0045] Furthermore, the front end of the expansion section 121 of the expansion portion 12 is connected to an auxiliary section 123 via an arc-shaped portion 122. The auxiliary section 123 is a cylindrical structure formed by extending along the longitudinal axis from the maximum diameter D of the expansion section 121 towards the front end. That is, when the involute tube 2 is fed towards the front end and reaches its maximum diameter D, its maximum expansion diameter D will not change. Under the action of the inner cone rod and the anchor hole, its front end is tightened and covers the auxiliary section 123 of the inner cone rod, thereby fixing the inner cone rod. This ensures that even when the inner cone rod loses its threaded connection with the involute tube, it remains stable and prevents it from loosening.

[0046] Furthermore, the angle between the first cone angle α on the inner cone rod 1 and the longitudinal axis ranges from 20° to 30°, and the longitudinal thickness of the auxiliary section 123 is smaller than the longitudinal thickness of the expansion section 121, so that the cutting segment expands into place. The first cone angle α is preferably 26°. This cone angle setting allows the cutting segment 221 of the involute tube 2 to be rotated open in a sliding state in the feed direction. That is, the annular section 24 of the involute tube 2 gradually and smoothly bends, thereby ensuring the effective connection and expansion of the cutting segment 221.

[0047] Furthermore, the involute 2 is made of hard alloy, such as tungsten carbide. Alternatively, the surface of the cutting segment 221 may be coated with diamond particles through an electroplating process. For example, diamond particles may be attached to the entire surface of the cutting segment 221 of the involute 2 to form a very sharp cutting edge, thereby enabling the simultaneous cutting of harder materials such as reinforcing steel bars in concrete.

[0048] Furthermore, in this embodiment, instead of the traditional method of using an inner cone rod protruding from the base and connecting bolts to fix the object, a fixed connecting pipe 4 with a cylindrical tubular structure is set on the inner cone rod 1, and the external bolt 3 is connected to the fixed connecting pipe 4 to fix the object, so that the anchor bolt sinks into the base, which facilitates the installation and fixing of the object.

[0049] Specifically, the outer diameter of the fixed connecting tube 4 is consistent with the maximum diameter D of the inner cone rod 1, meaning the fixed connecting tube 4 can be embedded in the anchor hole. The inner circumferential wall of the fixed connecting tube 4 is provided with a first connecting section 41 that engages with the rear external thread section 112 of the rod 11, a second connecting section 42 for fixing and connecting the external bolt 3, and a smooth extension section 43 located between the first connecting section 41 and the second connecting section 42. The first connecting section and the second connecting section are internal threads that match the inner cone rod and the external bolt. The extension section enables the connection of the external bolt to be flexible and adaptable. At the same time, fixed connecting tubes 4 of different lengths can be selected according to different scenario requirements to improve the applicability of the anchor bolt.

[0050] The method for anchoring involute anchors in a base provided in this embodiment includes the following steps:

[0051] a) Measure the longitudinal dimension of the inner cone rod 1 and the fixed connecting pipe 4 after they are fitted together, and define it as the anchor bolt length;

[0052] b) Drill a hole 5 on the base with a diameter consistent with the maximum diameter D, and the depth of the hole 5 is greater than the length of the anchor bolt;

[0053] c) Insert the inner cone rod 1, which has an involute tube 2, deep into the borehole 5 until the distance between the rear end of the inner cone rod 1 and the borehole opening is the distance at which the fixed connecting pipe 4 is installed (see attached diagram). Figure 4 (See left-hand illustration);

[0054] d) The inner cone rod 1 and the involute tube 2 are driven synchronously but at different speeds by a differential drill, thereby shortening the axial distance between the inner cone rod 1 and the involute tube 2 and gradually expanding the cutting segment 221 radially. At the same time, the cutting hole wall is rotated until the involute tube 2 is spinning freely in the borehole, thereby fixing the position of the inner cone rod 1 and the involute tube 2 in the borehole. Meanwhile, the debris generated from cutting the hole wall falls into the bottom of the borehole.

[0055] e) Rotate the fixed connecting tube 4 to the rear end of the inner cone rod 1 until the rear end of the fixed connecting tube 4 is flush with the borehole opening (see attached). Figure 4 (See diagram on the right);

[0056] f) Use external bolts 3 to fix the object (not shown) to the anchor bolt and lock it relative to the fixed connecting pipe 4 to complete the anchoring of the object.

[0057] In summary, the involute bottom anchor bolt provided by this utility model simplifies the installation process by setting the inner cone rod and the involute tube to be threadedly connected and rotating in the same direction but at different speeds. This allows the involute cutting part at the front end of the involute tube to gradually expand and cut the hole wall, forming a tapered hole for anchoring. This strengthens the tapered fit and prevents the anchor bolt from falling off or slipping out due to vibration of the fixed object. By setting the connection between the inner cone rod and the involute tube to a multi-segment threaded connection, the involute tube feeding process is stabilized while automatically stopping expansion upon completion, effectively protecting the safety and reliability of the driving tool and the base. By setting a fixed connecting pipe, the anchor bolt is sunk into the base, facilitating the installation and fixing of the fixed object while avoiding safety hazards at the fixing point. The involute bottom anchor bolt of this utility model has a simple structure and features an expansion-to-stop structure and a sunken installation structure, improving the applicability of the anchor bolt.

[0058] Many specific details have been set forth in the above description to provide a full understanding of this utility model. However, the above description is only a preferred embodiment of this utility model, and this utility model can be implemented in many other ways different from those described herein. Therefore, this utility model is not limited to the specific embodiments disclosed above. Furthermore, any person skilled in the art can make many possible variations and modifications to the technical solution of this utility model using the methods and techniques disclosed above, or modify it into equivalent embodiments with equivalent changes, without departing from the scope of the technical solution of this utility model. Any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this utility model, without departing from the content of the technical solution of this utility model, shall still fall within the protection scope of the technical solution of this utility model.

Claims

1. An involute bottom anchor bolt, characterized in that, include: The inner tapered rod (1) includes a rod portion (11) and an expansion portion (12) provided at the front end of the rod portion (11). The outer peripheral wall of the rod portion (11) is provided with an external thread section and an external smooth surface section along its longitudinal axis. The expansion portion (12) has an expansion section (121) that expands conically to the maximum diameter at a first cone angle (α) towards the front end along the axial direction of the rod portion (11). An involute tube (2) is rotatably mounted on the inner cone rod (1) and can rotate in the same direction with the inner cone rod (1) at different speeds. The involute tube (2) includes a connecting part (21) and an involute cutting part (22) provided at the front end of the connecting part (21). The inner peripheral wall of the connecting part (21) is provided with an internal thread section that meshes with the external thread section of the rod part (11). The involute cutting part (22) has multiple cutting segments (221), which can be gradually opened by the expansion section (121) when the involute tube (2) rotates and feeds towards the front end along the longitudinal axis relative to the inner cone rod (1), and cut the borehole wall to form a tapered hole. An external bolt (3) is connected to the external thread section of the inner cone rod (1) through a fixed connecting tube (4) to fix the object.

2. The involute anchor bolt according to claim 1, characterized in that: The rod portion (11) of the inner cone rod (1) has a cylindrical structure, and a tool interface (111) is provided at its rear end for mounting the tool at its rear end in a shape lock and in an anti-rotation manner. The external threaded section of the rod (11) includes a rear external threaded section (112) and a front external threaded section (113) arranged from back to front along the longitudinal axis; the smooth surface section of the rod (11) includes a rear smooth surface section (114) disposed between the rear external threaded section (112) and the front external threaded section (113), and a front smooth surface section (115) disposed between the front external threaded section (113) and the expansion portion (12); The rear external thread section (112) extends rearward from the rear external smooth section (114) along the longitudinal axis to the rear end of the inner tapered rod (1).

3. The involute anchor bolt according to claim 2, characterized in that: The involute tube (2) is a cylindrical tubular structure coaxial with the inner cone rod (1), and it is also provided with a tool connection port (23) for mounting the tool on its rear end in a shape-locking anti-rotation manner. The internal thread segment is provided on the inner peripheral wall of the connecting part (21), and the internal thread segment is configured to include: The rear internal thread section (211) is provided at one end near the tool connection port (23) and can engage with the rear external thread section (112); The front internal thread section (212) is provided at one end near the expansion portion (12) and can engage with the front external thread section (113).

4. The involute anchor bolt according to claim 3, characterized in that: An inner smooth section (213) is formed on the inner peripheral wall of the connecting part (21) between the rear inner thread section (211) and the front inner thread section (212). When the rear inner thread section (211) moves to the rear outer smooth section (114) of the rod (11) and the front inner thread section (212) moves to the front outer smooth section (115) of the rod (11), the inner tapered rod (1) no longer feeds to the rear end. At this time, the involute tube (2) and the inner tapered rod (1) are in a non-meshing connection state.

5. The involute anchor bolt according to claim 1, characterized in that: The involute cutting section (22) is cantilevered at the front end of the involute tube (2) via an annular section (24); The cutting segments (221) are provided in multiples, which are separated from each other by slits (222) along the circumferential direction and connected to each other by the annular segments (24), and the wall thickness of the annular segments (24) is less than the wall thickness of the involute cutting portion (22).

6. The involute anchor bolt according to claim 1, characterized in that: The front end of the expansion section (121) of the expansion portion (12) is connected to an auxiliary section (123) via an arc-shaped portion (122). The auxiliary section (123) is a cylindrical structure formed by extending along the longitudinal axis from the maximum diameter of the expansion section (121) to the front end.

7. The involute anchor bolt according to claim 6, characterized in that: The angle between the first cone angle (α) and the longitudinal axis ranges from 20° to 30°; the longitudinal thickness of the auxiliary section (123) is smaller than the longitudinal thickness of the expansion section (121).

8. The involute anchor bolt according to claim 1, characterized in that: The involute tube (2) is made of hard alloy.

9. The involute anchor bolt according to claim 2, characterized in that: The surface of the cutting segment (221) is coated with diamond grit by an electroplating process.

10. The involute anchor bolt according to claim 2, characterized in that: The fixed connecting tube (4) is a cylindrical tubular structure, and its outer diameter is consistent with the maximum diameter of the inner conical rod (1); The inner circumferential wall of the fixed connecting pipe (4) is provided with a first connecting section (41) that engages with the rear external thread section (112) of the rod (11), a second connecting section (42) for fixing the external bolt (3), and a smooth extension section (43) between the first connecting section (41) and the second connecting section (42).

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