Limiting counter bore drill

Abstract

According to the technical scheme, the limiting counter bore drill is characterized by comprising a drill body, a twist drill, a tool bit body and a locking structure. A limiting ring is fixed to the head of the drill body, a center channel and a tool bit body are arranged in the drill body, the tool bit body is matched with the twist drill through a mounting through groove, and the tool bit body and the twist drill are locked with the drill body through the same locking structure. The locking structure comprises a locking hole in the drill body, a set screw and a key groove or a notch in the side face of the tool bit body, and the set screw penetrates through the locking hole to press the twist drill, so that the tool bit body is tightly attached to the inner wall of the center channel, and locking is completed. Meanwhile, a measuring scale is arranged on the periphery of the extension part of the tool bit body, and an observation opening is formed in the periphery of the limiting ring, so that the depth is convenient to adjust. Counter bore parts with different diameters are arranged at the two ends of the tool bit body, and diversified machining requirements are met. According to the design, synchronous locking of the twist drill and the tool bit body is achieved through an independent locking structure, the adjusting operation process is simplified, the adjusting efficiency is improved, the twist drill is particularly suitable for the scene where the drilling depth is frequently switched, and the machining efficiency and accuracy are remarkably improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to drill bit technical field, concretely relates to a limit counterbore drill. BACKGROUND

[0002] The limit counterbore drill is a commonly used drill bit in wood processing, which is mainly used for drilling a central hole and a counterbore of a certain depth on wood, so as to be used for installing screws or mortise and tenon connection, and the counterbore is used to ensure that the top of the screw does not protrude from the surface of the wood, thereby ensuring the aesthetic degree of wood processing.

[0003] However, in the existing limit counterbore drill, the position of the twist drill and the position of the limiting structure are locked by two independent locking structures, and when the user needs to adjust the drilling depth and the counterbore depth, the user needs to operate the locking screw and the screw respectively to adjust the positions of the two components, which is very cumbersome, and in some scenarios where the drilling depth needs to be frequently switched, especially in the process of furniture manufacturing, it is very troublesome to frequently adjust the drilling depth and the counterbore depth, which greatly affects the production efficiency of the user. SUMMARY

[0004] The utility model provides a limit counterbore drill, which solves the problem that in the existing limit counterbore drill, the twist drill and the limiting structure are locked by two independent locking structures, which makes the adjustment of the positions of the twist drill and the limiting structure very cumbersome and affects the work efficiency.

[0005] To achieve the above-mentioned purpose, the utility model adopts the technical scheme of a limit counterbore drill, which comprises a drill body, a limiting ring is fixedly arranged on the head of the drill body, a central passage is arranged in the drill body, one end of the central passage corresponding to the limiting ring is open, a cutter body is arranged inside the central passage, an installation slot is formed in one end of the cutter body corresponding to the limiting ring, and a twist drill is arranged in the installation slot.

[0006] The utility model further sets up, the locking structure includes setting on the drill body locking hole, tight screw and setting on the keyway or the notch of the side of the tool bit body and with the position of locking hole correspondence, the keyway communicates with the installation through the groove, the tight screw one end passes through the locking hole and the keyway or the notch and compresses the twist drill in the installation through the groove, and the tool bit body is close to the inner wall of the center channel when the twist drill is pressed to realize position locking.

[0007] The utility model further sets up, when setting on the side of the tool bit body is the keyway, it is rectangular or oval, the tight screw one end is arranged in the keyway.

[0008] The utility model further sets up, the twist drill includes the plug-in part and the working part, the plug-in part is arranged in the installation through the groove, and its circumferential side is provided with the limiting surface that is combined with the end face of tight screw, the limiting surface is the planar shape that is combined with the end of tight screw.

[0009] The utility model further sets up, the tool bit body includes the extension part that sets up in the center channel, one end of the extension part is provided with the counterbore part with cutting edge, the keyway is arranged in the circumferential side of the extension part.

[0010] The utility model further sets up, the extension part circumferential side is provided with the measuring scale, and the limiting ring circumferential side is provided with the observation port that is combined with the position of measuring scale.

[0011] The utility model further sets up, the installation through the groove is set up and is passed through the tool bit body, the counterbore part is provided with two, and it is arranged respectively in the both ends of the extension part, and the counterbore diameter that two counterbores process is different.

[0012] The utility model further sets up, the drill body is provided with the handle that is integrally formed with the drill body or is split combination with the tail of one end far from the head.

[0013] The utility model further sets up, when the handle is split combination with the drill body, the tail end surface of the drill body is provided with the plug-in hole that is inserted and cooperates with the handle, the handle one end is inserted in the plug-in hole, and one end inserted in the plug-in hole is provided with screwdriver head.

[0014] The utility model further sets up, the handle portion and the plug -in hole are through quick -witted structure realizes detachable connection between, the quick -witted structure includes the assembly hole of setting in the tail of the drill body and the ring groove of setting in the handle portion one end with the assembly hole position correspondence, the assembly hole with plug -in hole vertical and intercommunication, the assembly hole is rolled in and is provided with the ball bearing, still include the connecting bushing of setting in the tail of the drill body outside, the connecting bushing drill body between setting has reset spring, the connecting bushing inside setting has the drive ring, when the drive ring of connecting bushing drives reset spring compression, the clearance for the ball bearing to move outward between the connecting bushing inner wall and assembly hole to remove the engagement of handle portion and plug -in hole, when reset spring drive connecting bushing reset slip, the drive ring in the connecting bushing will extrude the ball bearing and move inwards to realize the engagement of plug -in hole and handle portion.

[0015] To sum up, the beneficial effects of the utility model:

[0016] The utility model discloses a limiting counterbore drill, which is innovatively designed with a locking structure, so that the twist drill and the tool head body can be jointly locked through the same locking structure, the operation process is simplified, and the working efficiency is greatly improved. Unlike the prior art in which the twist drill and the limiting structure use independent locking mechanisms respectively, the utility model fastens the twist drill and the tool head body in the same structure, and simultaneously adjusts the two components. Specifically, the locking hole and the key groove are designed in cooperation, so that when the depth of the twist drill is adjusted, the tool head body can also be adjusted accordingly, without the need to operate multiple structural components respectively, and time delay and operation complexity that may occur in the adjustment process are avoided. This simplified adjustment mechanism can effectively improve the adjustment speed of the user to the drilling depth and the counterbore depth during the machining process, especially in application scenarios where the drilling depth needs to be frequently switched, the overall production efficiency can be significantly improved; the traditional double-locking structure thinking is broken through, and the problem of adjusting the counterbore depth by adjusting the limiting ring is solved, so that the problem of complicated operation of the prior art is solved by the unique single-locking structure and the fixed limiting ring design. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is the three-dimensional structure diagram of the utility model.

[0018] Figure 2 is the explosion decomposition diagram of the utility model.

[0019] Figure 3 is the perspective view of the tool head body of the utility model.

[0020] Figure 4 is the perspective view of the twist drill of the utility model.

[0021] Figure 5 is the cooperation section view of the twist drill and the tool head body of the utility model.

[0022] Figure 6 is the assembly diagram of the handle part and the drill body.

[0023] Figure 7 is the perspective view of the second embodiment of the utility model.

[0024] Figure 8 is the structural diagram of the third embodiment of the utility model.

[0025] Figure 9 is the structural diagram of the fourth embodiment of the utility model.

[0026] Reference signs: 1, drill body; 2, limiting ring; 3, handle part; 4, tool bit body; 41, extension part; 42, counterbore part; 43, cutting edge; 44, measurement scale; 45, observation port; 5, twist drill; 51, plug-in part; 52, working part; 53, limiting surface; 6, central passage; 7, installation through slot; 8, locking structure; 81, locking hole; 82, locking screw; 83, key groove; 9, plug-in hole; 10, screwdriver bit; 11, assembly hole; 12, ring groove; 13, ball; 14, connecting bush; 15, return spring; 16, driving ring; 17, notch; 18, connecting rod; 19, chamfering and edging tool bit; 20, limiting plate. DETAILED DESCRIPTION

[0027] The technical scheme in the embodiments of the utility model will be described clearly and completely below in conjunction with the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor are involved in the scope of the utility model.

[0028] As shown in Figures 1-9 The application discloses a limiting counterbore drill, compared with a traditional limiting counterbore drill, the design idea that the traditional counterbore drill adopts two sets of locking structures 8 to respectively lock the positions of a limiting ring 2 and a twist drill 5, and the depth of the counterbore is adjusted by adjusting the position of the limiting ring 2 is broken through.

[0029] Embodiment one

[0030] As shown in Figures 1-2As shown, including drill body 1, the head of the drill body 1 is fixedly provided with a limiting ring 2, the tail is provided with a handle 3 connected with the external drilling machine; the drill body 1 is provided with a central channel 6, the central channel 6 is opened at one end corresponding to the limiting ring 2, the inside is provided with a cutter head body 4, the cutter head body 4 is opened with an installation through slot 7 at one end corresponding to the limiting ring 2, the installation through slot 7 is provided with a twist drill 5; wherein, the twist drill 5 and the cutter head body 4 can slide relative to each other, the cutter head body 4 and the drill body 1 can slide relative to each other, and the twist drill 5 can slide relative to each other through the cutter head body 4 and the drill body 1; through the above structure, the relative position between the twist drill 5 and the cutter head body 4 can be adjusted to adjust the length of the twist drill 5 extending out of the cutter head body 4, and then the depth of the counterbore drill hole is controlled.

[0031] By adjusting the relative position between the cutter head body 4 and the drill body 1, the distance between the counterbore cutter at the end of the cutter head body 4 and the limiting ring 2 is adjusted, and finally the adjustment of the counterbore depth is realized.

[0032] And, through the same locking structure 8 provided on the drill body 1, the position locking between the twist drill 5 and the cutter head body 4, the cutter head body 4 and the drill body 1 is realized at the same time.

[0033] Further, as shown in the figure, Figures 2-5 The locking structure 8 includes a locking hole 81 provided on the drill body 1, a tight screw 82 and a key groove 83 or a notch 17 provided on the side of the cutter head body 4 and corresponding to the locking hole 81, the key groove 83 communicates with the installation through slot 7; one end of the tight screw 82 passes through the locking hole 81 and the key groove 83 to press the twist drill 5 in the installation through slot 7, and the cutter head body 4 is in close contact with the inner wall of the central channel 6 when the twist drill 5 is pressed to realize the position locking.

[0034] As shown in the figure, Figure 3 In this embodiment, the key groove 83 on the cutter head body 4 is in the form of a long strip such as a rectangle or an ellipse, which makes the end of the tight screw 82 screwed in the locking hole 81 of the drill body 1 pass through the key groove 83 when the relative position between the cutter head body 4 and the drill body 1 changes in the length direction, so as to press the twist drill 5 in the installation through slot 7 from the side, make the twist drill 5 tightly fit the inner wall of the installation through slot 7 under the action of external force, and realize the position locking between the twist drill 5 and the cutter head body 4. At the same time, the twist drill 5 is arranged in the installation through slot 7 of the cutter head body 4, the pressure applied by the tight screw 82 to the twist drill 5 is transmitted to the cutter head body 4, so that the cutter head body 4 is tightly fitted with the inner wall of the central channel 6 of the drill body 1, thereby generating friction between the outer wall of the cutter head body 4 and the inner wall of the central channel 6 of the drill body 1, and realizing the position locking between them.

[0035] Through experiments, it is found that the pressure applied by the clamping screw 82 to the twist drill 5 and the tool head body 4 is sufficient to enable the twist drill 5 to complete the drilling work on the wood board and other materials without slipping, thereby for the field of home, which does not require high drilling accuracy and needs to adjust the drilling depth according to the processed product or position change, the simultaneous locking of the positions of the twist drill 5 and the tool head body 4 by only one clamping screw 82 can effectively reduce the parts of the counterbore drill, thereby simplifying the structure of the counterbore drill, and the simultaneous locking or unlocking of the twist drill 5 and the tool head body 4 by controlling the tightness of one clamping screw 82 can enable the worker to simultaneously adjust the drilling depth and the counterbore depth, thereby avoiding the time delay and operation complexity that may occur in the adjustment process, saving the adjustment time of the worker in the work scene that needs to be frequently adjusted, and finally improving the work production efficiency.

[0036] In the embodiment, the key groove 83 enables the user to prevent the end of the clamping screw 82 from exiting the key groove 83 when the clamping screw 82 is loosened, thereby enabling the user to avoid the rotation of the tool head body 4 in the central passage 6 when adjusting the length direction positions of the twist drill 5 and the tool head body 4, and playing a limiting role.

[0037] Further, as shown in Figure 4 , the twist drill 5 includes a plug-in part 51 and a working part 52, the plug-in part 51 is slidingly arranged in the mounting slot 7, and a limiting surface 53 abutting the end surface of the clamping screw 82 is arranged on the peripheral side of the plug-in part 51, the limiting surface 53 is in a planar shape, on this basis, the clamping screw 82 is a flat-end screw, and the end thereof is in a plane abutting the limiting surface 53, thereby in the locking process, the contact area between the end surface of the clamping screw 82 and the limiting surface 53 can be increased, the friction between the twist drill 5 and the screw can be improved, the pressing area of the screw on the twist drill 5 can be increased, and the acting force between the twist drill 5 and the tool head body 4 can be enhanced, thereby ensuring that the positions of the twist drill 5 and the tool head body 4 will not be easily changed in the locked state, and the working stability is improved.

[0038] Further, as shown in Figure 3 , the tool head body 4 includes an extension part 41 slidingly arranged in the central passage 6, the extension part 41 is provided with a counterbore part 42 with a cutting edge 43 at one end, and the key groove 83 is arranged on the peripheral side of the extension part 41; specifically, the counterbore part 42 with the cutting edge 43 can form a counterbore for accommodating the head of a screw at the opening of a hole when the twist drill 5 drills, thereby ensuring that the screw is flush with the surface of the material after installation, and improving the appearance of the material after drilling. By adjusting the relative position of the extension part 41 in the central passage 6, the relative distance between the cutting edge 43 and the limiting ring 2 can be adjusted, and the adjustment of the counterbore depth to adapt to different sizes of screws is completed.

[0039] Further, as shown in Figure 3 , the extension part 41 is provided with a measuring scale 44 on the side, and the limiting ring 2 is provided with an observation hole 45 corresponding to the position of the measuring scale 44, and the measuring scale 44 can be observed through the observation hole 45 to realize the measurement of the distance between the cutting edge 43 and the limiting ring 2, so that the depth of the counterbore can be more accurately controlled.

[0040] Further, as shown in Figure 3 , the installation slot 7 can be provided through the drill bit body 4, and the counterbore part 42 is provided with two, which are respectively arranged at both ends of the extension part 41, and the counterbores processed by the two counterbore parts 42 are different in diameter; The setting of the double-head counterbore part 42 can make the staff more convenient and fast to replace different end parts according to the size of the screw head, so that the staff does not need to carry too many counterbore drills, and the product is more convenient to carry; At the same time, the setting of the double-head drill bit body 4 effectively reduces the cost of the product, and one drill bit body 4 can replace the traditional two-size drill bit body 4, so that the production and sales cost is lower.

[0041] Further, as shown in Figure 2 , Figure 7 , the tail of the drill body 1, that is, the end of the drill body 1 away from the limiting ring 2 is provided with a handle 3 combined with the drill body 1, when the handle 3 is combined with the drill body 1, the tail end surface of the drill body 1 is provided with a plug-in hole 9 matched with the handle 3, one end of the handle 3 is clamped in the plug-in hole 9, and the end inserted into the plug-in hole 9 is provided with a screwdriver bit 10; Through the handle 3 combined in parts, the user can control the rotation of the whole limiting counterbore drill by connecting the handle 3 with the electric drill; At the same time, after the limiting counterbore drill completes the drilling and counterboring operation, the user can disassemble and separate the drill body 1 from the handle 3, so that the electric drill is only connected with the handle 3, and the end of the handle 3 away from the electric drill is provided with a screwdriver bit 10, so that the user can directly screw the screw into the hole through the screwdriver bit 10 of the handle 3, so that it is not necessary to replace the connecting part of the electric drill repeatedly, which improves the work efficiency and reduces the cost of additional purchase of the screwdriver bit 10, thereby reducing the cost.

[0042] Further, as shown in Figure 6As shown, the detachable connection between the shank 3 and the insertion hole 9 is achieved through a quick connection structure; the quick connection structure comprises an assembly hole 11 arranged on the tail side of the drill body 1 and a ring groove 12 arranged on one end of the shank 3 corresponding to the position of the assembly hole 11, the assembly hole 11 is perpendicular to and communicates with the insertion hole 9, and the assembly hole 11 is arranged with a ball 13 rolling therein; further comprising a connecting bush 14 sleeved on the outer tail of the drill body 1, the connecting bush 14 is arranged with a reset spring 15 between the drill body 1, and the inner side of the connecting bush 14 is arranged with a driving ring 16; when the driving ring 16 of the connecting bush 14 drives the reset spring 15 to compress, a gap is generated between the inner wall of the connecting bush 14 and the assembly hole 11 for the outward movement of the ball 13 to release the clamping of the shank 3 and the insertion hole 9; when the reset spring 15 drives the connecting bush 14 to reset and slide, the driving ring 16 in the connecting bush 14 will extrude the ball 13 to move inward to achieve the clamping of the insertion hole 9 and the shank 3.

[0043] Through the arrangement of the quick connection structure, the user can easily complete the connection and disassembly between the shank 3 and the drill body 1. Figure 6 As shown, in the initial state, the connecting bush 14 is driven by the reset spring 15, the driving ring 16 in the connecting bush 14 is at the outer end of the assembly hole 11, and the ball 13 is limited in the assembly hole 11; and the ring groove 12 is arranged on the side of the one end of the shank 3 with a screw head.

[0044] When the shank 3 is connected with the drill body 1; first, the connecting bush 14 is pushed towards the reset spring 15, so that the reset spring 15 is compressed and the driving ring 16 moves away from the assembly hole 11 to release the limitation of the ball 13; at this time, the shank 3 is inserted into the insertion hole 9, and as the one end of the shank 3 gradually penetrates into the insertion hole 9, the ring groove 12 on the side of the shank 3 gradually approaches the assembly hole 11, until the ball 13 is clamped into the ring groove 12 when reaching the position of the assembly hole 11; then, the connecting bush 14 is loosened, and the driving ring 16 is slid to the outside of the assembly hole 11 under the driving of the reset spring 15, so as to limit and extrude the ball 13, so that the ball 13 cannot be separated from the ring groove 12 of the shank 3, thereby achieving the clamping locking of the position of the shank 3, and completing the connection of the shank 3 and the drill body 1.

[0045] Similarly, when the separation between the shank 3 and the drill body 1 needs to be completed, first, the driving ring 16 on the connecting bush 14 is driven to release the limitation of the ball 13, at this time, the ball 13 can slide in the assembly hole 11, then the shank 3 is pulled out of the insertion hole 9, and during the pulling-out process, since the ball 13 can move freely, the ball 13 will be separated from the ring groove 12, so that the shank 3 can be separated from the insertion hole 9, and finally the disassembly and separation of the shank 3 and the drill body 1 are completed.

[0046] Example Two

[0047] Based on example one, as shown in Figure 7As shown, at the tail of the drill body 1, that is, at the end away from the limiting ring 2, there is a handle 3 integrally formed with the tail of the drill body 1. The handle 3 is configured as a hexagonal handle, a square handle, or a square interface, which can be connected to an external electric drill to realize the driving drilling operation of the limiting countersunk drill.

[0048] Example 3

[0049] like Figure 8 As shown, the keyway 83 on the cutter head body 4 can be configured as a notch 17 that connects to the mounting slot 7. The notch 17 is used to allow the end of the set screw 82 to better press against the twist drill 5. Meanwhile, the cutting edge 43 of the countersunk hole 42 can be an alloy cutting edge integrally formed with the cutter head body 4.

[0050] Example 4

[0051] like Figure 9 As shown in Embodiment 1, since the limiting countersink drill has a relatively simple function and can only realize the function of limiting countersinking, in this embodiment, the cutter head body 4 and twist drill 5 on the drill body 1 can also be disassembled by controlling the set screw 82 and replaced as needed to realize other operating functions.

[0052] In this embodiment, a cutting head that matches the drill bit is provided. It is a trimming and chamfering cutting head, but not limited to this type of cutting head. The cutting head provided in this embodiment includes a connecting rod 18 that is inserted into the central channel 6 of the drill body 1. A hole corresponding to the locking hole 81 is provided on the periphery of the connecting rod 18. The set screw 82 can pass through the locking hole 81 and be threaded into the hole to achieve a locking connection of the connecting rod 18. A chamfering and trimming cutting head 19 and a limiting plate 20 are fixedly connected to the end of the connecting rod 18 away from the drill body 1. The chamfering and trimming cutting head 19 passes through the limiting plate 20 and is located below the limiting plate 20.

[0053] In use, the user can connect the chamfering and trimming cutter head 19 to the drill body 1 via the connecting rod 18. The drill body 1 is then connected to the electric drill, which allows the electric drill to drive the chamfering and trimming cutter head 19 to rotate, thereby chamfering and repairing the edge corners of the material. The limiting plate 20 can fit against the material surface to ensure the horizontal movement of the cutter head. The chamfering and trimming cutter head is existing technology, and its specific structure will not be described in detail.

[0054] With the above-described chamfering and trimming cutter structure, users can achieve chamfering and trimming functions or drilling functions by replacing the cutter head on the drill body 1, which improves the practicality of the limiting countersunk drill, makes it easier for users to carry, and reduces the cost of the tool.

[0055] The above merely describes preferred embodiments of the present application and is not intended to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the design concept of the present application shall be included in the protection scope of the present application.

Claims

1. A limiting countersink drill, comprising a drill body (1), characterized in that, The head of the drill body (1) is fixedly provided with a limiting ring (2). A central channel (6) is provided inside the drill body (1). The central channel (6) is open at one end corresponding to the limiting ring (2). A cutter head body (4) is provided inside the central channel (6). A mounting slot (7) is opened at one end corresponding to the limiting ring (2). A twist drill (5) is provided in the mounting slot (7). The drill body (1) also includes a locking structure (8) provided on the drill body (1). The cutter head body (4) and the twist drill (5) are connected and locked to the drill body (1) through the common locking structure (8).

2. The limiting countersink drill according to claim 1, characterized in that, The locking structure (8) includes a locking hole (81) and a set screw (82) on the drill body (1) and a keyway (83) or notch (17) on the side of the cutter head body (4) corresponding to the position of the locking hole (81). The keyway (83) is connected to the mounting through groove (7). One end of the set screw (82) passes through the locking hole (81) and the keyway (83) or notch (17) to press the twist drill (5) tightly into the mounting through groove (7). When the twist drill (5) is pressed, the cutter head body (4) is in close contact with the inner wall of the central channel (6) to achieve position locking.

3. A limiting countersink drill according to claim 2, characterized in that, When the keyway (83) is provided on the side of the cutter head body (4), it is rectangular or elliptical, and one end of the set screw (82) is slidably disposed in the keyway (83).

4. A limiting countersink drill according to claim 1, characterized in that, The twist drill (5) includes a plug part (51) and a working part (52). The plug part (51) is slidably disposed in the mounting through groove (7), and a limiting surface (53) is provided on its periphery to fit with the end face of the set screw (82). The limiting surface (53) is a plane that fits with the end of the set screw (82).

5. A limiting countersink drill according to claim 3, characterized in that, The cutter head body (4) includes an extension (41) disposed in the central channel (6), one end of the extension (41) is provided with a countersunk hole (42) with a cutting edge (43), and the keyway (83) is disposed on the periphery of the extension (41).

6. A limiting countersink drill according to claim 5, characterized in that, The extension (41) is provided with a measuring scale (44) around its periphery, and the limiting ring (2) is provided with an observation port (45) corresponding to the position of the measuring scale (44) around its periphery.

7. A limiting countersink drill according to claim 6, characterized in that, The mounting groove (7) is provided through the cutter head body (4), and there are two countersunk holes (42), which are respectively provided at both ends of the extension (41). The countersunk holes processed by the two countersunk holes (42) have different diameters.

8. A limiting countersink drill according to any one of claims 1-4, characterized in that, The drill body (1) has a shank (3) at the end furthest from the head, which is integrally formed or separately assembled with the drill body (1).

9. A limiting countersink drill according to claim 8, characterized in that, When the shank (3) and the drill body (1) are assembled separately, the end face of the tail of the drill body (1) is provided with a plug hole (9) that is engaged with the shank (3). One end of the shank (3) is inserted into the plug hole (9), and the end inserted into the plug hole (9) is provided with a screwdriver head (10).

10. A limiting countersink drill according to claim 9, characterized in that, The shank (3) and the insertion hole (9) are detachably connected by a quick-connect structure. The quick-connect structure includes an assembly hole (11) on the periphery of the tail of the drill body (1) and an annular groove (12) on one end of the shank (3) corresponding to the position of the assembly hole (11). The assembly hole (11) is perpendicular to and communicates with the insertion hole (9). A ball bearing (13) is rolled inside the assembly hole (11). The quick-connect structure also includes a connecting bushing (14) sleeved on the tail of the drill body (1). A return spring (15) is provided between the connecting bushing (14) and the drill body (1). A drive ring (16) is provided on the inner side of the connecting bushing (14). When the drive ring (16) of the connecting bushing (14) drives the return spring (15) to compress, a gap is generated between the inner wall of the connecting bushing (14) and the assembly hole (11) to allow the ball (13) to move outward so as to release the engagement between the handle (3) and the insertion hole (9). When the return spring (15) drives the connecting bushing (14) to return to its original position and slide, the drive ring (16) inside the connecting bushing (14) will squeeze the ball (13) to move inward so as to achieve the engagement between the insertion hole (9) and the handle (3).

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