Pile foundation rotary drilling hole cleaning drill bit

Abstract

The utility model relates to rotary digging hole cleaning drill bit technical field especially a pile foundation rotary digging hole cleaning drill bit, including cylinder, its inner wall is provided with a plurality of longitudinal extension limit slot along the circumference, movable bottom plate is set up in the bottom of cylinder, and the movable bottom plate is fixed with a plurality of slide bars that correspond with limit slot one to one and can slide along it, annular scraper, fixedly connected in the upper end of a plurality of slide bars, and its outer edge and the inner wall of cylinder are inlaid. The linkage slag cleaning mechanism that limit slot of slide bar, annular scraper and cylinder inner wall constitute, in the process of pulling out the drill, the self weight of residual drill slag in the cylinder and its friction with the hole wall will drive movable bottom plate to produce the displacement downward relative to the cylinder, and this displacement is accurately transmitted to the annular scraper fixed on the top of the slide bar through the slide bar, forces the scraper to adhere to the cylinder inner wall to move from top to bottom, converts the conventional pulling out the drill action to the cleaning power, thereby can automatically, thoroughly scrape off the drill slag adhered in the cylinder inner wall.

Description

Technical Field

[0001] This utility model relates to the field of rotary drilling and hole cleaning drill bits, and in particular to a rotary drilling and hole cleaning drill bit for pile foundations. Background Technology

[0002] Existing rotary drilling bits for pile foundations typically employ a cylindrical drill body combined with a bottom cutting mechanism. Specifically, the drill bit is a hollow cylinder with a bottom plate. Several cutting teeth or bucket teeth are mounted on the bottom plate. During drilling, the power head drives the drill body to rotate, causing the bottom teeth to cut and break the rock and soil. The broken rock and soil (or "drill cuttings") are guided into and temporarily stored in the upper cylinder cavity under the continuous rotation and pressure of the drill bit. As the drilling depth increases, the drill cuttings accumulate in the cylinder and are discharged from the drill bit through the upper end of the cylinder. Combined with the drill lifting process, the drill cuttings are continuously discharged from the pile hole, thus achieving continuous drilling depth.

[0003] However, the aforementioned traditional rotary drilling bits exhibit a significant drawback in actual construction: after drilling to the current hole position and retrieving the drill bit, or during work breaks, some drill cuttings remain inside the drill bit barrel due to their adhesion, friction, or dead zones in the internal structure. The handling of these residual drill cuttings is typically passive: either relying on manual cleaning, which increases worker workload, reduces construction efficiency, and poses safety hazards; or leaving them for the next drilling operation, relying on newly arriving drill cuttings to "squeeze" them out. The latter method is particularly unreliable, as it can lead to the mixing and compaction of old and new drill cuttings, increasing drill bit load and reducing drilling efficiency. More seriously, the residual drill cuttings may form a non-dense fill at the bottom of the drill bit, affecting the initial stability of the drill bit and the vertical accuracy of the borehole when opening new holes, and may even cause premature drill bit damage. Therefore, how to effectively and automatically remove residual drill cuttings from the drill bit after shutdown has become an urgent technical problem to be solved. Utility Model Content

[0004] Therefore, the technical problem to be solved by this utility model is that after the traditional rotary drilling bit stops, drilling slag remains in its cylinder, and there is a lack of an effective automatic cleaning mechanism, which makes cleaning difficult and affects the efficiency and quality of subsequent drilling operations.

[0005] The above-mentioned technical problems are solved by the following technical solution: This utility model proposes a rotary drilling and cleaning drill bit for pile foundations, including a cylinder with multiple longitudinally extending limiting grooves arranged circumferentially on its inner wall; a movable base plate disposed at the bottom of the cylinder, with multiple sliding rods fixed on the movable base plate corresponding one-to-one with the limiting grooves and slidable along them; and an annular scraper fixedly connected to the upper end of the multiple sliding rods, with its outer edge fitting against the inner wall of the cylinder; wherein, the movable base plate has a notch for soil to enter, and the lower surface of the movable base plate is provided with cutting teeth corresponding to the notch.

[0006] In a preferred embodiment of the rotary drilling and hole cleaning drill bit for pile foundations described in this utility model: the upper surface of the movable base plate is a conical surface that gradually decreases from its center to its edge.

[0007] In a preferred embodiment of the rotary drilling and hole cleaning drill bit for pile foundations of this utility model: the bottom surface of the cylinder is provided with multiple recesses, and the upper surface of the movable base plate is provided with multiple protrusions that are adapted to the recesses.

[0008] In a preferred embodiment of the rotary drilling and hole cleaning drill bit for pile foundations described in this utility model: the cross-sections of the notch and the protrusion are non-circular and mutually complementary.

[0009] In a preferred embodiment of the rotary drilling and hole clearing drill bit for pile foundations of this utility model: each notch is located on the front side of the rotational forward direction corresponding to one of the cutting teeth.

[0010] In a preferred embodiment of the rotary drilling and hole cleaning drill bit for pile foundations described in this utility model: the annular scraper is fixed to the upper end of all the slide bars by welding or fasteners.

[0011] In a preferred embodiment of the rotary drilling and hole cleaning drill bit for pile foundations of this utility model: the limiting groove is a T-shaped groove or a dovetail groove, and the sliding rod has a head that cooperates with the limiting groove.

[0012] In a preferred embodiment of the rotary drilling and hole cleaning drill bit for pile foundations described in this utility model: the sliding rod and the movable base plate are integrally formed or connected by threads.

[0013] In a preferred embodiment of the rotary drilling and hole cleaning drill bit for pile foundations of this utility model: the cutting teeth are fixed to the lower surface of the movable base plate by welding or detachment.

[0014] In a preferred embodiment of the rotary drilling and hole cleaning drill bit for pile foundations described in this utility model: the cutting edge of the annular scraper is in line contact or surface contact with the inner wall of the cylinder.

[0015] The beneficial effects of this invention are as follows: First, it achieves efficient and automatic internal slag removal, effectively improving construction efficiency and operational safety. This effect is attributed to the linked slag removal mechanism composed of a sliding rod, an annular scraper, and a limiting groove on the inner wall of the cylinder. During the drilling process, the weight of the residual drill cuttings inside the cylinder and the friction between them and the borehole wall drive the movable base plate to move downward relative to the cylinder. This displacement is precisely transmitted to the annular scraper fixed to its top via the sliding rod, forcing the scraper to move from top to bottom while adhering closely to the inner wall of the cylinder. This mechanical linkage process transforms the conventional drilling action into a cleaning power source, thereby automatically and thoroughly scraping away the drill cuttings adhering to the inner wall of the cylinder. This fundamentally solves the problems of low efficiency, high labor intensity, and high risk of high-altitude operations caused by traditional drill bits relying on manual cleaning.

[0016] Secondly, it ensures a smooth and thorough cleaning process and significantly enhances the structural rigidity and stability of the drill bit during operation. Firstly, the scraped-off drill cuttings can be quickly and completely discharged thanks to the conical surface design on the upper surface of the movable base plate. This conical surface provides an ideal guiding slope for the falling cuttings, allowing them to slide smoothly under gravity and be discharged through the gap between the base plate and the cylinder, effectively preventing secondary accumulation and blockage above the base plate. Secondly, during drilling operations, the overall rigidity and torque transmission efficiency of the drill bit are guaranteed. This is achieved through the interlocking fit of a non-circular protrusion and recess between the bottom surface of the cylinder and the upper surface of the movable base plate. When the protrusion is inserted into the recess, its non-circular mating side effectively resists huge torsional loads, preventing relative rotation between the base plate and the cylinder, and ensuring the reliability of power transmission and the accuracy of the drilling trajectory under heavy-load cutting conditions. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings of the embodiments of this utility model will be briefly described below. Obviously, the drawings described below only relate to some embodiments of this utility model and are not intended to limit the scope of this utility model. Wherein:

[0018] Figure 1 3D diagram of a rotary drilling bit for pile foundation cleaning Figure 1 ;

[0019] Figure 2 3D diagram of a rotary drilling bit for pile foundation cleaning Figure 2 ;

[0020] Figure 3 A cross-sectional schematic diagram of a rotary drilling bit for cleaning holes in pile foundations;

[0021] Figure 4 for Figure 3 Enlarged schematic diagram of the structure at point A in the middle;

[0022] Figure 5 A schematic diagram of the connection of a rotary drilling and hole cleaning drill bit for pile foundations;

[0023] Figure 6 This is a schematic diagram of the overall structure of the rotary drilling and hole cleaning device for pile foundations.

[0024] In the picture:

[0025] 1. Cylinder body; 11. Limiting groove; 12. Notch;

[0026] 2. Movable base plate; 21. Notch; 22. Conical surface; 23. Protrusion;

[0027] 3. Slide bar;

[0028] 4. Circular scraper;

[0029] 5. Cutting teeth. Detailed Implementation

[0030] To enable those skilled in the art to better understand this utility model, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0031] The terminology used in this invention refers to those general terms currently widely used in the art in consideration of the functionality of this invention; however, these terms may vary according to the intent, precedent, or new technology of those skilled in the art. Furthermore, specific terms may be chosen by the applicant, and in such cases, their detailed meanings will be described in the detailed description of this invention. Therefore, the terminology used in this specification should not be construed as simple names, but rather based on the meaning of the terms and the overall description of this invention.

[0032] Reference Figures 1-6 This embodiment provides a rotary drilling and cleaning drill bit for pile foundations, including a cylinder 1 with multiple longitudinally extending limiting grooves 11 arranged circumferentially on its inner wall; a movable base plate 2, disposed at the bottom of the cylinder 1, with multiple sliding rods 3 fixed on the movable base plate 2 corresponding one-to-one with the limiting grooves 11 and slidable along them; and an annular scraper 4, fixedly connected to the upper end of the multiple sliding rods 3, with its outer edge fitting against the inner wall of the cylinder 1; wherein, the movable base plate 2 has a notch 21 for soil to enter, and the lower surface of the movable base plate 2 is provided with cutting teeth 5 corresponding to the notch 21.

[0033] A rotary drilling and cleaning drill bit for pile foundations aims to solve the technical problems of easy drilling slag residue and difficult cleaning inside the cylinder 1 of traditional drill bits. It achieves automatic cleaning of the inner wall of the cylinder 1 during drilling, without the need for additional power or manual intervention. Specifically, it includes a cylinder 1, a movable base plate 2, a slide bar 3, an annular scraper 4, and cutting teeth 5. The cylinder 1 is the main structure of this drill bit, typically a cylindrical steel component. Its inner wall has multiple longitudinally extending limiting grooves 11 arranged circumferentially and at equal intervals. These limiting grooves 11 provide a precise guiding trajectory for the slide bar 3, ensuring that the movable base plate 2 can only slide axially (up and down) relative to the cylinder 1, without relative rotation or detachment.

[0034] The movable base plate 2 is located at the bottom of the cylinder 1, and its shape is adapted to the bottom opening of the cylinder 1. The movable base plate 2 is connected to the cylinder 1 by multiple sliding rods 3. The sliding rods 3 are fixed (e.g., by welding or threaded connection) to the movable base plate 2, and their number and position correspond one-to-one with the limiting grooves 11 on the inner wall of the cylinder 1. Each sliding rod 3 extends into a corresponding limiting groove 11 and can slide freely along the limiting groove 11. This sliding connection relationship constitutes the basis for the relative movement between the movable base plate 2 and the cylinder 1.

[0035] An annular scraper 4 is fixedly connected to the upper end of all the sliding rods 3. The outer edge of the scraper is machined to ensure that it can fit tightly against the inner wall of the cylinder 1. The annular scraper 4 moves synchronously with the sliding rods 3. When the sliding rods 3 descend under the guidance of the limiting groove 11, the scraper scrapes across the inner wall of the cylinder 1 from top to bottom, completely removing the adhering drill cuttings.

[0036] On the movable base plate 2, there are multiple openings 21 for soil to enter. At the same time, multiple cutting teeth 5 are fixedly installed on the lower surface of the movable base plate 2. Each cutting tooth 5 corresponds to a notch 21. This layout allows the rock and soil broken off by the cutting teeth 5 to be smoothly guided and enter the upper cylinder 1 for temporary storage through the notch 21.

[0037] In a preferred embodiment of this invention, the upper surface of the movable base plate 2 is specifically designed as a tapered surface 22 that gradually decreases in height from its center to its edge. The structure of this tapered surface 22 is similar to an inverted truncated cone or an umbrella-shaped structure, with its highest point located at or near the geometric center of the movable base plate 2. Starting from this point, the surface smoothly and continuously extends outwards towards the periphery of the movable base plate 2. The core function of this geometric design is to guide and discharge drill cuttings.

[0038] Specifically, during the drilling and cuttings removal process, when the annular scraper 4 scrapes off the cuttings adhering to the inner wall of the cylinder 1, these cuttings will naturally fall to the upper surface of the movable base plate 2. At this time, the conical surface 22 provides a natural guiding slope for the falling cuttings. Under the action of gravity, the cuttings will automatically and smoothly slide along this slope to the annular gap created by the relative separation between the cylinder 1 and the movable base plate 2, and finally be completely discharged from the outside of the drill bit through this gap. This design effectively avoids the accumulation or caking of the removed cuttings on the upper surface of the movable base plate 2, ensuring the continuity and thoroughness of the cuttings removal process, thereby significantly improving the self-cleaning efficiency of the drill bit. The conical surface 22 can be integrally formed by casting or machined onto the base plate substrate.

[0039] In a key implementation of the drill bit, a notch 21 on the movable base plate 2 is positioned in front of the corresponding cutting pawl 5 in the direction of rotation. When the drill bit is driven and rotates along its preset drilling direction, in the trajectory of any cutting pawl 5, its corresponding notch 21 always passes through and contacts the rock and soil working surface to be cut first. Subsequently, the cutting pawl 5 follows and performs concentrated and effective crushing operations on the area that has been partially disturbed by the notch 21. This "notch 21 in front, pawl behind" layout constitutes an efficient material flow guiding system. Thus, when the notch 21 on the front side cuts into the soil layer first, it not only creates favorable conditions for the cutting of the pawl but also directly provides an immediate and unobstructed entry channel for the drill cuttings generated after crushing. The rock and soil crushed by the cutting pawl 5 is naturally and almost synchronously "fed" or "sweeped" into the notch 21 in front of it under the combined action of the centrifugal force of the drill bit's rotation and the subsequent propulsion force, thereby quickly entering the interior of the upper cylinder 1. This structural design significantly improves chip removal efficiency, effectively preventing the accumulation, blockage, or repeated cutting of broken drill cuttings in front of and at the bottom of the cutting teeth 5. This reduces the rotational resistance and energy loss of the drill bit, ensuring the continuity and efficiency of the drilling process.

[0040] In a preferred embodiment of the drill bit, multiple notches 12 are formed on the bottom surface of the cylinder 1. Simultaneously, multiple protrusions 23, matching the number, position, and shape of these notches 12, are provided on the upper surface of the movable base plate 2. These notches 12 and protrusions 23 are designed in cross-section as non-circular structures that interlock. Here, "non-circular" means that, viewed from a perspective perpendicular to the drill bit's axis, the outline shape of the notches 12 and protrusions 23 is not circular; their specific shapes can include, but are not limited to, rectangles, polygons, ellipses, or irregular shapes with keyways. The core function of this non-circular mating design is to effectively resist relative rotation between the protrusions 23 and the notches 12 around the drill bit's axis when the protrusions 23 are embedded in the notches 12. During drilling operations, when a large torque is transmitted from the cylinder 1 to the movable base plate 2, this structure transmits the torsional load through surface contact between the non-circular sidewalls, thereby greatly enhancing the torsional rigidity and overall structural strength of the connection between the base plate and the cylinder 1, ensuring the drill bit's operational stability and reliability under heavy-load cutting conditions.

[0041] In a key implementation of the drill bit, the annular scraper 4 is securely fixed to the upper end of all the slide rods 3 by welding or fasteners, thus forming an integrated linkage slag removal mechanism. When welding is used, continuous or intermittent full welding can be performed at the connection between the scraper and each slide rod 3 to ensure the strength and rigidity of the connection. When fasteners are used, bolts are preferred for connection, that is, through holes are provided at corresponding positions of the scraper and slide rod 3, and detachable fixing is achieved by the cooperation of bolts and nuts. This multi-point fixing method ensures that the annular scraper 4 can move synchronously and smoothly with the slide rods 3, and will not deviate or jam due to uneven force.

[0042] Furthermore, the cutting edge of the annular scraper 4 is configured to make either line contact or surface contact with the inner wall of the cylinder 1. Line contact means that the cutting edge of the scraper adheres to the inner wall of the cylinder 1 in a continuous, sharp annular line. This method can scrape away tightly adhered drill cuttings with extremely high local pressure, resulting in thorough cleaning and relatively low resistance. Surface contact means that the cutting edge of the scraper adheres to the inner wall of the cylinder 1 in an annular guide surface of a certain width. This method enhances the guidance and stability of the scraper during its up-and-down movement, improves the wear life of the scraper, and can simultaneously scrape away a layer of drill cuttings. Whether it is line contact or surface contact, the core purpose is to ensure a continuous, uniform, and effective interaction between the scraper and the cylinder wall, thereby ensuring that the residual drill cuttings on the inner wall of the cylinder 1 can be completely and smoothly scraped off and guided downwards during the drilling process, achieving a reliable self-cleaning function.

[0043] In a preferred embodiment of the drill bit, the limiting groove 11 provided on the inner wall of the cylinder 1 is a T-groove or a dovetail groove; correspondingly, the end of the slide rod 3 is machined with a head that precisely matches the shape and size of the T-groove or dovetail groove. This T-groove or dovetail groove-head mating structure constitutes an effective anti-detachment mechanism. Its working principle is that after the head of the slide rod 3 is inserted into the limiting groove 11 from the side, its size is larger than the neck of the groove opening, thus being mechanically constrained in the groove in the radial direction. This design can reliably prevent the slide rod 3 from accidentally detaching from the limiting groove 11 when subjected to complex working conditions such as drill cuttings weight, vibration, or inclined operation, ensuring the effectiveness and safety of the sliding connection between the movable base plate 2 and the cylinder 1. In addition, this large contact area mating form, compared with the simple rectangular groove mating with the slide rod 3, can more evenly distribute the contact stress, improve the durability of the guide component, and make the sliding of the slide rod 3 in the groove more stable, further ensuring the smooth execution of the cuttings removal action.

[0044] In one specific implementation of the drill bit, the slide rod 3 and the movable base plate 2 are securely connected through one of two preferred methods: First, an integral molding structure, where the slide rod 3 and the movable base plate 2 are cast or forged into a single metal component. This manufacturing method achieves optimal structural strength and rigidity, avoiding potential loosening or fatigue failure at the connection point, and is particularly suitable for harsh working conditions subjected to severe impacts and heavy loads. Second, a threaded connection, where external threads are machined at the end of the slide rod 3, and corresponding mounting holes with internal threads are provided at the corresponding positions on the movable base plate 2. By screwing in the threads, the slide rod 3 can be reliably fixed to the movable base plate 2. The advantage of this method is that it facilitates the individual machining, replacement, and maintenance of each component. To ensure reliable connection under vibration, thread-locking adhesive can be applied during assembly, or anti-loosening washers can be added under the nuts. Both connection methods effectively ensure the reliability of force transmission between the slide rod 3 and the movable base plate 2, thereby ensuring the stable operation of the entire slag removal linkage mechanism during repeated drilling and hoisting cycles.

[0045] In one specific implementation of the drill bit's fixing of the cutting jaws 5, two reliable connection methods are provided to adapt to different working conditions and maintenance needs. The first method involves fixing the cutting jaws 5 to the lower surface of the movable base plate 2 by welding. Specifically, the jaw base and the pre-defined mounting position on the movable base plate 2 are fused together using high-temperature welding (such as manual arc welding or gas shielded welding). This method creates a connection joint with extremely high structural strength and connection rigidity, reliably transmitting the enormous impact and vibration loads generated during drilling, making it particularly suitable for long-term use in harsh conditions such as hard rock formations. The second method involves fixing the cutting jaws 5 in a detachable manner. This connection method allows for independent replacement of individual jaws when they wear or are damaged, without scrapping the entire movable base plate 2, significantly improving the maintainability and economy of the drill bit. The specific implementation structure can include, but is not limited to, the following forms: A through hole is provided on the cutting jaw 5, and a threaded hole is machined at the corresponding position on the movable base plate 2. A high-strength bolt is inserted from the back of the jaw and screwed into the base plate, thereby pressing and fixing the two together; or, a mechanical locking structure combining wedges and pins is used, where the jaw is embedded into a slot on the base plate and locked with a transverse pin or wedge. Welding ensures the permanence and reliability of the connection; detachable design provides convenience for maintenance and flexibility in use. Both fixing methods ensure that the cutting jaw 5 remains firmly positioned when subjected to complex cutting forces, thus guaranteeing continuous and efficient drilling operations.

[0046] Reference Figures 1-6 The working process of this utility model drill bit is mainly divided into two stages: drilling operation and drill bit removal and slag cleaning.

[0047] Drilling operation stage: When the drill bit is lowered to start drilling, the movable base plate 2 first contacts the ground. As the drill bit continues to apply downward pressure, the cylinder 1 continues to move downward relative to the base plate. At this time, each sliding rod 3 fixed on the movable base plate 2 slides upward along the corresponding limiting groove 11, driving the annular scraper 4 to move upward synchronously. Finally, the bottom surface of the cylinder 1 is tightly attached to the upper surface of the movable base plate 2, and all sliding rods 3 are completely retracted into the limiting groove 11. At the same time, the protrusion 23 on the movable base plate 2 and the recess 12 on the bottom surface of the cylinder 1 are interlocked and engaged. This state realizes the effective sealing of the bottom of the cylinder 1 by the base plate and reliably transmits the driving torque from the cylinder 1 to the base plate and the cutting tooth 5.

[0048] Subsequently, the drill bit is driven to rotate to drill a hole, and the cutting teeth 5 break the rock and soil. The drill cuttings produced are continuously introduced into the cylinder 1 through the notch 21 on the movable base plate 2 and temporarily stored under the centrifugal force of the rotating drill bit and the subsequent drilling cuttings. As the drilling depth increases, the drill cuttings accumulated in the cylinder 1 rise continuously and are eventually discharged from the top of the cylinder 1, thereby achieving the drilling depth.

[0049] Drill bit removal and slag removal stage: When it is necessary to stop or move the machine, the drill bit is lifted out of the hole. Under the weight of the drill slag in the cylinder 1, the friction with the hole wall, and the inertia of the drill bit being lifted, the movable bottom plate 2 and the cylinder 1 are relatively displaced. That is, the bottom plate lags behind the cylinder 1 in moving downward. This action causes the slide bar 3 to slide downward along the limiting groove 11, thereby driving the annular scraper 4 to scrape the entire inner wall of the cylinder 1 from top to bottom.

[0050] During this process, the annular scraper 4, which fits tightly against the cylinder wall, effectively removes the drill cuttings adhering to the inner wall. The scraped-off drill cuttings fall onto the upper surface of the conical movable base plate 2 and are then completely discharged from the outside of the drill bit through the annular gap between the movable base plate 2 and the cylinder 1, falling to the bottom of the hole or into a collection point. This achieves automatic and efficient cuttings removal inside the drill bit.

[0051] This invention transforms the conventional "drill lifting" action in operation into a power source for cleaning slag, achieving automatic cleaning without additional power or manual intervention. This not only significantly improves construction efficiency and avoids the impact of drill slag caking on subsequent drilling quality, but also fundamentally eliminates the safety hazards of manual cleaning.

[0052] Finally, it should be noted that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways as long as they do not depart from the scope of this utility model.

Claims

1. A rotary drilling bit for cleaning holes in pile foundations, characterized in that: It includes a cylindrical body (1), whose inner wall is provided with multiple longitudinally extending limiting grooves (11) along the circumferential direction; A movable base plate (2) is provided at the bottom of the cylinder (1). Multiple sliding rods (3) are fixed on the movable base plate (2) and correspond one-to-one with the limiting groove (11) and can slide along it. The annular scraper (4) is fixedly connected to the upper end of the multiple sliding rods (3), and its outer edge is in contact with the inner wall of the cylinder (1); The movable base plate (2) has a notch (21) for soil to enter, and the lower surface of the movable base plate (2) is provided with a cutting claw (5) corresponding to the notch (21).

2. The rotary drilling bit for cleaning pile foundation holes according to claim 1, characterized in that: The upper surface of the movable base plate (2) is a tapered surface (22) that gradually decreases from its center to its edge.

3. The rotary drilling bit for cleaning pile foundation holes according to claim 1, characterized in that: The bottom surface of the cylinder (1) is provided with a plurality of recesses (12), and the upper surface of the movable base plate (2) is provided with a plurality of protrusions (23) that are adapted to the recesses (12).

4. The rotary drilling bit for cleaning pile foundation holes according to claim 3, characterized in that: The cross-sections of the notch (12) and the protrusion (23) are non-circular and fit together.

5. The rotary drilling bit for cleaning pile foundation holes according to claim 1, characterized in that: Each of the notches (21) is located on the front side of the rotational forward direction of the corresponding cutting tooth (5).

6. The rotary drilling bit for cleaning pile foundation holes according to claim 1, characterized in that: The annular scraper (4) is fixed to the upper end of all the slide bars (3) by welding or fasteners.

7. The rotary drilling bit for cleaning pile foundation holes according to claim 1, characterized in that: The limiting groove (11) is a T-shaped groove or a dovetail groove, and the slide rod (3) has a head that cooperates with the limiting groove (11).

8. The rotary drilling bit for cleaning pile foundation holes according to claim 1, characterized in that: The slide bar (3) and the movable base plate (2) are integrally formed or connected by threads.

9. The rotary drilling bit for cleaning pile foundation holes according to claim 1, characterized in that: The cutting claw (5) is fixed to the lower surface of the movable base plate (2) by welding or detachment.

10. The rotary drilling bit for cleaning pile foundation holes according to claim 1, characterized in that: The cutting edge of the annular scraper (4) is in line contact or surface contact with the inner wall of the cylinder (1).

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