Reverse counter boring cutter handle

Abstract

The reverse counter boring cutter handle comprises a main shaft sleeve, a telescopic shaft sleeve and a counter boring shaft, the main shaft sleeve is fixedly arranged on the counter boring shaft in a sleeving mode, the telescopic shaft sleeve is movably arranged on the counter boring shaft in a sleeving mode, and a locking mechanism is arranged between the main shaft sleeve and the telescopic shaft sleeve. The locking mechanism is suitable for being locked or unlocked through relative movement of the main shaft sleeve and the telescopic shaft sleeve in the axial direction of the countersinking shaft, a movable tool bit is arranged on the countersinking shaft, a tool edge is formed in the telescopic shaft sleeve, when the locking mechanism is unlocked, the tool bit is suitable for stretching out of the tool edge, and the telescopic shaft sleeve is suitable for limiting the tool bit to retract from the tool edge. When the locking mechanism is changed from unlocking to locking, the telescopic shaft sleeve is suitable for enabling the tool bit to retract into the tool edge, and when the locking mechanism is locked, the telescopic shaft sleeve is suitable for limiting the tool bit to stretch out of the tool edge, and the reverse countersinking device has the advantages of being compact in size and convenient to operate, and reverse countersinking can be conducted on small hole sites through automatic stretching and retracting of the tool bit.

Description

Technical Field

[0001] The present application relates to the field of cutting processing technology, and in particular to a reverse countersinking tool holder. Background Art

[0002] Countersinking refers to machining cylindrical countersunk holes, tapered countersunk holes, and boss end faces on already machined holes. When the countersink is located on the back of the hole, reverse countersinking is required.

[0003] However, the existing reverse countersinking tools have the following defects: At present, common reverse countersinking tools are generally tool holders for manual installation and adjustment of the cutter head depth, and tool holders that use centrifugal force to extend and retract the cutter head. These two types of tool holders are either inconvenient to operate and have a limited countersinking range, or have requirements for the minimum rotation speed of the tool holder, and both have their limitations in usage scenarios. Summary of the Invention

[0004] One purpose of the present application is to provide a reverse countersinking tool holder that is compact and easy to operate.

[0005] To achieve the above objectives, the technical solution adopted in the present application is: a reverse countersinking tool holder, comprising a main shaft sleeve, a telescopic sleeve and a countersinking shaft, the main shaft sleeve being fixedly sleeved on the countersinking shaft, the telescopic sleeve being movably sleeved on the countersinking shaft, a locking mechanism being provided between the main shaft sleeve and the telescopic sleeve, the locking mechanism being suitable for locking or unlocking through the relative movement of the main shaft sleeve and the telescopic sleeve along the axial direction of the countersinking shaft, a movable cutter head being provided on the countersinking shaft, a cutting edge being provided on the telescopic sleeve, when the locking mechanism is unlocked, the cutter head being suitable for extending from the cutting edge, and the telescopic sleeve being suitable for limiting the cutter head from being retracted from the cutting edge, when the locking mechanism changes from unlocking to locking, the telescopic sleeve being suitable for retracting the cutter head into the cutting edge, and when the locking mechanism is locked, the telescopic sleeve being suitable for limiting the cutter head from extending out of the cutting edge.

[0006] In some embodiments, the cutter head is rotatably connected to the countersinking shaft, and a blocking portion is provided on the countersinking shaft. The cutter head is suitable for rotating close to the blocking portion to extend the cutting edge, and the cutter head is suitable for rotating away from the blocking portion to be retracted into the cutting edge. When the telescopic sleeve and the countersinking shaft move relative to each other, the blocking portion is suitable for approaching one side of the cutting edge and cooperating with one side of the cutting edge on both sides of the cutter head to limit the rotation of the cutter head. The blocking portion is suitable for approaching the other side of the cutting edge and causing the other side of the cutting edge to push the cutter head away from the blocking portion.

[0007] In some embodiments, a pop-up mechanism is provided on the countersinking shaft. When the locking mechanism is unlocked, the pop-up mechanism is suitable for rotating the cutter head close to the blocking portion, and at least makes the rotation of the cutter head suitable for being continued by the telescopic sleeve.

[0008] In some embodiments, the locking mechanism includes a lock, a first resetter and a second resetter. The lock is telescopically arranged on the main shaft sleeve, and a locking portion is provided on the telescopic sleeve. The first resetter is arranged between the main shaft sleeve and the telescopic sleeve. The first resetter is suitable for resetting so that the main shaft sleeve and the telescopic sleeve are away from each other. The lock is suitable for extending out of the main shaft sleeve and cooperating with the locking portion to limit the resetting of the first resetter. The second resetter is arranged on the telescopic sleeve, and the second resetter is suitable for cooperating with the lock to release the cooperation between the lock and the locking portion.

[0009] In some embodiments, the second resetter includes a disengagement member and a reset member, the disengagement member is slidably arranged on the telescopic sleeve, the reset member is arranged between the disengagement member and the locking portion, a guide portion is provided on the disengagement member, the locker is suitable for being engaged with the guide portion and suitable for making the disengagement member close to the locking portion, and when the disengagement member is in contact with the locking portion, the guide portion is suitable for making the locker pass through the locking portion.

[0010] In some embodiments, a locking section and a disengagement section are sequentially formed on the upper edge of the lock close to the telescopic sleeve, the length of the locking section along the axial direction of the countersinking shaft is not greater than the maximum distance between the disengagement piece and the locking portion, and the length of the disengagement section along the axial direction of the countersinking shaft is greater than the minimum distance between the disengagement piece and the locking portion.

[0011] In some embodiments, the outermost end of the guide portion protrudes from the outermost end of the locking portion; and the elastic modulus of the first resetter is smaller than the elastic modulus of the reset member.

[0012] In some embodiments, there are multiple lockers, and the lockers are arranged along the circumference of the countersinking shaft.

[0013] In some embodiments, a step portion is provided on the telescopic sleeve, and the blade is provided on the lower side of the step portion.

[0014] In some embodiments, a positioning groove is provided on the telescopic sleeve, and a locator is provided on the countersinking shaft. The locator and the positioning groove are axially slidably matched with each other along the countersinking shaft. The locator and the positioning groove are suitable for cooperating to limit the movement of the telescopic sleeve in the circumferential direction of the countersinking shaft. The locator and the positioning groove are suitable for cooperating to limit the relative movement stroke of the main sleeve and the telescopic sleeve along the axial direction of the countersinking shaft.

[0015] Compared with the prior art, the beneficial effects of the present application are: the reverse countersinking tool holder of the present application is provided with an automatic telescopic structure, which can actively control the extension or retraction of the cutter head, and is more flexible in use. The automatic telescopic structure can be used to design the part of the tool holder that extends into the hole to be more compact, so as to cope with penetrating into holes with smaller apertures and achieve higher difficulty hole processing. Moreover, the automatic telescopic structure is stable and easy to trigger, and has sufficient stability during the countersinking processing of the reverse countersinking tool holder. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is an overall structural view according to a preferred embodiment of the present application.

[0017] Figure 2 It is a schematic diagram of the structure in the locked state according to a preferred embodiment of the present application.

[0018] Figure 3 According to a preferred embodiment of the present application Figure 2 Magnified view at point a.

[0019] Figure 4 It is a structural diagram of the unlocking process according to a preferred embodiment of the present application.

[0020] Figure 5 According to a preferred embodiment of the present application Figure 4 Magnified view at point b.

[0021] Figure 6 It is a structural diagram of the unlocked state according to a preferred embodiment of the present application.

[0022] In the figure: 1. main shaft sleeve; 2. telescopic sleeve; 21. cutting edge; 22. locking portion; 23. step portion; 24. positioning groove; 3. countersinking shaft; 31. cutter head; 32. accommodating cavity; 321. blocking portion; 33. ejection mechanism; 34. positioner; 4. locking mechanism; 41. lock; 411. locking section; 412. disengagement section; 42. first resetter; 43. second resetter; 431. disengagement member; 4311. guide portion; 432. reset member. DETAILED DESCRIPTION

[0023] Below, the present application is further described in conjunction with specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0024] In the description of this application, it should be noted that for directional words, such as the terms "center", "horizontal", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and so on, the directions and positional relationships indicated are based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and cannot be understood as limiting the specific scope of protection of this application.

[0025] It should be noted that the terms "first", "second", etc. in the description and claims of this application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0026] The terms "comprises" and "having" and any variations thereof in the specification and claims of this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus that includes a series of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, product or apparatus.

[0027] The present application will be further described below with reference to the accompanying drawings:

[0028] like Figures 1 to 6 As shown, the present application provides a reverse countersinking tool holder, comprising a main shaft sleeve 1, a telescopic shaft sleeve 2 and a countersinking shaft 3. The main shaft sleeve 1 is fixedly sleeved on the countersinking shaft 3, and the telescopic shaft sleeve 2 is movably sleeved on the countersinking shaft 3. The telescopic shaft sleeve 2 is suitable for sliding along the axial direction of the countersinking shaft 3. When the telescopic shaft sleeve 2 slides along the axial direction of the countersinking shaft 3, relative movement occurs between the main shaft sleeve 1 and the telescopic shaft sleeve 2. A locking mechanism 4 is provided between the main shaft sleeve 1 and the telescopic shaft sleeve 2. The locking mechanism 4 is suitable for locking or unlocking through the relative movement of the main shaft sleeve 1 and the telescopic shaft sleeve 2 along the axial direction of the countersinking shaft 3. The operation form of triggering the locking mechanism 4 in this way is relatively simple, which is in line with the traditional use of the reverse countersinking tool holder. It only needs to extend and expand the process of the reverse countersinking tool holder inserting into the hole position, without additional operation, and the operation difficulty is relatively low.

[0029] A movable cutter head 31 is provided on the countersinking shaft 3, and a cutting edge 21 is opened on the telescopic sleeve 2. When the locking mechanism 4 is unlocked, the cutter head 31 is suitable for extending from the cutting edge 21, and the telescopic sleeve 2 is suitable for limiting the cutter head 31 from being retracted from the cutting edge 21. When the locking mechanism 4 changes from unlocking to locking, the telescopic sleeve 2 is suitable for retracting the cutter head 31 into the cutting edge 21. When the locking mechanism 4 is locked, the telescopic sleeve 2 is suitable for limiting the cutter head 31 from extending out of the cutting edge 21.

[0030] like Figure 2 and 6 The cam 321 is provided with a stopper 321 to move the tool 31 closer to the stopper 321 so as to extend the tool 31 and retract the tool 31 into the workpiece 31. The cam 321 is provided with a stopper 321 to move the tool 31 closer to the stopper 321 so as to extend the tool 31 and retract the tool 31 into the workpiece 31. When the cam 321 is in the workpiece 31, the stopper 321 is provided with a stopper 321 to move the tool 31 closer to the stopper 321 so as to retract the tool 31 into the workpiece 31.

[0031] In some embodiments, the rotation plane of the cutter head 31 is parallel to the axis of the countersinking shaft 3, so that the cutter head 31 can have higher structural strength and stability when countersinking with the countersinking shaft 3 in forward or reverse rotation, making the tool holder run more stably.

[0032] In some embodiments, the rotation and folding direction of the cutter head 31 is set to be close to the back direction of the hole position. After opening, the cutter head 31 can be restricted by the blocking portion 321 when countersinking. Compared with being restricted by the blade 21, it can have higher stability. At the same time, the cutter head 31 will not be accidentally folded during the countersinking process, thereby improving the stability of the countersinking.

[0033] like Figure 2 、 4 In the embodiment shown in Figure 6, a cavity 32 is provided on the countersink shaft 3, and the blocking portion 321 is a side wall of the cavity 32. The cutter head 31 is suitable for rotating and retracting into the cavity 32. When the cutter head 31 is rotated and extended, it can interfere with the side wall of the cavity 32.

[0034] In some embodiments, a pop-up mechanism 33 is provided on the countersinking shaft 3. When the locking mechanism 4 is unlocked, the pop-up mechanism 33 is suitable for rotating the cutter head 31 close to the blocking portion 321, and at least makes the rotation of the cutter head 31 suitable for being continued by the telescopic sleeve 2, that is, when the pop-up mechanism 33 moves to the extreme position, the cutter head 31 will not continue to rotate, but as the telescopic sleeve 2 slides, the blade 21 can reach the protruding part of the cutter head 31, and then as the blade 21 moves, it can drive the cutter head 31 to continue to rotate as a whole until the cutter head 31 reaches the blocking portion 321, thus completing the entire pop-up process of the cutter head 31.

[0035] like Figure 2In the embodiment shown, the pop-up mechanism 33 preferably uses a bent spring sheet, one end of which is fixed on the countersinking shaft 3 and located on the retracted side of the cutter head 31, and the other end of the bent spring sheet is suitable for contacting the cutter head 31. It has a simple structure, is easy to install, and saves space.

[0036] like Figure 2 In the illustrated embodiment, the ejection mechanism 33 is accommodated in the cavity 32 , and the embedded structure can improve compactness and stability.

[0037] It is understandable that by designing the size of the cavity 32, the specifications of the cutter head 31, the size of the blade 21, etc., different countersinking specifications can be achieved without changing the minimum aperture into which the tool handle can be inserted, which has higher applicability.

[0038] In some embodiments, the locking mechanism 4 includes a locker 41, a first resetter 42 and a second resetter 43. The locker 41 is telescopically arranged on the main shaft sleeve 1. The telescopic sleeve 2 is provided with a locking portion 22. The first resetter 42 is arranged between the main shaft sleeve 1 and the telescopic sleeve 2. The first resetter 42 is suitable for resetting so that the main shaft sleeve 1 and the telescopic sleeve 2 are away from each other. The locker 41 is suitable for extending out of the main shaft sleeve 1 and cooperating with the locking portion 22 to limit the resetting of the first resetter 42. The second resetter 43 is arranged on the telescopic sleeve 2. The second resetter 43 is suitable for cooperating with the locker 41 to release the cooperation between the locker 41 and the locking portion 22.

[0039] In some embodiments, the locker 41 is extended and retracted on the main shaft sleeve 1 by a spring.

[0040] In some embodiments, the first resetter 42 is a spring. The first resetter 42 is sleeved on the countersinking shaft 3 , and two ends of the first resetter 42 respectively abut against the main shaft sleeve 1 and the telescopic shaft sleeve 2 .

[0041] like Figures 2 to 6 In the illustrated embodiment, the second resetter 43 includes a disengagement member 431 and a reset member 432. The disengagement member 431 is slidably arranged on the telescopic sleeve 2, and the reset member 432 is arranged between the disengagement member 431 and the locking portion 22. A guide portion 4311 is provided on the disengagement member 431. The locker 41 is suitable for being engaged with the guide portion 4311 and for making the disengagement member 431 close to the locking portion 22. When the disengagement member 431 and the locking portion 22 are in contact, the locker 41 can overcome the engagement with the guide portion 4311. At this time, the guide portion 4311 is suitable for making the locker 41 pass through the locking portion 22.

[0042] In some embodiments, the side of the lock 41 close to the guide portion 4311 is designed with an inclined surface, which can contact the guide portion 4311 and help the lock 41 move and slide onto the guide portion 4311.

[0043] In some embodiments, the disengagement member 431 is an annular structure, and the disengagement member 431 is sleeved on the telescopic sleeve 2 . The annular design of the disengagement member 431 can improve the matching stability between the locker 41 and the disengagement member 431 .

[0044] like Figure 3 and 5 In the embodiment shown, a locking section 411 and a disengagement section 412 are sequentially formed on the lock 41 in the direction close to the telescopic sleeve 2. The axial length of the locking section 411 along the countersinking shaft 3 is not greater than the maximum distance between the disengagement piece 431 and the locking portion 22, ensuring that the lock 41 can be correctly engaged with the locking portion 22 between the disengagement piece 431 and the locking portion 22, thereby improving the engagement stability. The axial length of the disengagement section 412 along the countersinking shaft 3 is greater than the minimum distance between the disengagement piece 431 and the locking portion 22, ensuring that the lock 41 can be completely pushed out after the disengagement piece and the locking portion 22 are close to each other, thereby releasing the engagement between the lock 41 and the locking portion 22.

[0045] In some embodiments, the guide portion 4311 is designed with an inclined surface at the contact portion with the lock 41. The inclined surface can contact the lock 41 and give the guide portion 4311 and the lock 41 a force to maintain the engagement. This force must be greater than the force of the elastic deformation of the reset member 432 overcome by the contact between the guide portion 4311 and the locking portion 22. When the guide portion 4311 and the locking portion 22 interfere with each other, the lock 41 will overcome and adapt to the engagement force between the guide portion 4311 by telescoping. When the lock 41 moves to the top of the guide portion 4311, it can smoothly utilize the interference between the guide portion 4311 and the locking portion 22 for transition and movement. When the locking portion 22 moves in the opposite direction, the lock 41 can pass over the locking portion 22 to achieve unlocking.

[0046] In some embodiments, the outermost end of the guide portion 4311 protrudes from the outermost end of the locking portion 22, ensuring that the lock 41 can move from the outermost end of the guide portion 4311 to the outermost end of the locking portion 22 without being stuck with the locking portion 22, thereby passing through the locking portion 22 more smoothly.

[0047] In some embodiments, the elastic modulus of the first resetter 42 is smaller than the elastic modulus of the reset member 432. The elastic moduli of the first resetter 42 and the reset member 432 are used to distinguish between the unlocked and locked states of the knife handle, ensuring that the unlocked state of the locker 41 can be correctly triggered and operated.

[0048] In some embodiments, there are multiple lockers 41 , and the lockers 41 are arranged circumferentially along the countersinking shaft 3 . The more lockers 41 there are, the better the locking effect of the telescopic sleeve 2 is, and the higher the stability is.

[0049] In some embodiments, when there are multiple lockers 41 , the lockers 41 can be arranged at equal intervals along the circumference of the countersinking shaft 3 to improve the uniformity of the locking force of the telescopic sleeve 2 in the circumferential direction, thereby improving the locking stability.

[0050] In some embodiments, a step portion 23 is provided on the telescopic sleeve 2, and the blade 21 is provided on the lower side of the step portion 23. It can be understood that by designing the higher side of the step portion 23 to be located outside the hole, when locking and unlocking the handle, it is only necessary to push the higher side of the step portion 23 of the telescopic sleeve 2 against the periphery of the hole (such as Figure 4 As shown), the telescopic sleeve 2 and the main sleeve 1 can move with each other.

[0051] like Figure 1 、 2 In the embodiments shown in , 4 and 6, a positioning groove 24 is provided on the telescopic sleeve 2, and a positioner 34 is provided on the countersinking shaft 3. The positioner 34 and the positioning groove 24 are axially slidably matched with the countersinking shaft 3. The positioner 34 and the positioning groove 24 are suitable for cooperating to limit the movement of the telescopic sleeve 2 in the circumferential direction of the countersinking shaft 3, that is, they can limit the relative movement of the telescopic sleeve 2 and the main shaft sleeve 1 in the circumferential direction of the countersinking shaft 3, so as to improve stability and prevent the telescopic sleeve 2 from contacting the cutter head 31, thereby protecting the cutter head 31.

[0052] The locator 34 and the locating groove 24 are suitable for cooperating to limit the relative movement of the main shaft sleeve 1 and the telescopic sleeve 2 along the axial direction of the countersinking shaft 3. By setting the locking and unlocking strokes within the relative movement strokes of the main shaft sleeve 1 and the telescopic sleeve 2, the stability of unlocking and locking can be improved and the probability of structural interference and jamming can be reduced.

[0053] The above describes the basic principles, main features, and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above-described embodiments. The above-described embodiments and the specification merely illustrate the principles of the present application. Various changes and improvements may be made to the present application without departing from the spirit and scope of the present application. These changes and improvements fall within the scope of the present application for which protection is sought. The scope of protection claimed by the present application is defined by the appended claims and their equivalents.

Claims

1. A reverse countersinking toolholder, characterized by: The invention comprises a main shaft sleeve, a telescopic sleeve and a countersinking shaft, wherein the main shaft sleeve is fixedly mounted on the countersinking shaft, and the telescopic sleeve is movably mounted on the countersinking shaft. A locking mechanism is arranged between the main shaft sleeve and the telescopic sleeve, and the locking mechanism is suitable for locking or unlocking by relative movement of the main shaft sleeve and the telescopic sleeve along the axial direction of the countersinking shaft. A movable cutter head is arranged on the countersinking shaft, and a cutting edge is provided on the telescopic sleeve. When the locking mechanism is unlocked, the cutter head is suitable for extending from the cutting edge, and the telescopic sleeve is suitable for limiting the cutter head from being retracted from the cutting edge. When the locking mechanism changes from unlocking to locking, the telescopic sleeve is suitable for retracting the cutter head into the cutting edge. When the locking mechanism is locked, the telescopic sleeve is suitable for limiting the cutter head from extending from the cutting edge.

2. A reverse countersinking tool holder according to claim 1, characterized in that: The cutter head is rotatably connected to the countersinking shaft, and a blocking portion is provided on the countersinking shaft. The cutter head is suitable for rotating close to the blocking portion to extend the cutting edge, and the cutter head is suitable for rotating away from the blocking portion to be retracted into the cutting edge. When the telescopic sleeve and the countersinking shaft move relative to each other, the blocking portion is suitable for approaching one side of the cutting edge and cooperating with one side of the cutting edge on both sides of the cutter head to limit the rotation of the cutter head. The blocking portion is suitable for approaching the other side of the cutting edge and causing the other side of the cutting edge to push the cutter head away from the blocking portion.

3. The reverse countersinking tool holder according to claim 2, characterized in that: The countersinking shaft is provided with a pop-up mechanism. When the locking mechanism is unlocked, the pop-up mechanism is suitable for rotating the cutter head close to the blocking portion, and at least makes the rotation of the cutter head suitable for being continued by the telescopic sleeve.

4. The reverse countersinking tool holder according to claim 1, characterized in that: The locking mechanism includes a locker, a first resetter and a second resetter. The locker is telescopically arranged on the main shaft sleeve. A locking portion is provided on the telescopic sleeve. The first resetter is arranged between the main shaft sleeve and the telescopic sleeve. The first resetter is suitable for resetting so that the main shaft sleeve and the telescopic sleeve are away from each other. The locker is suitable for extending out of the main shaft sleeve and cooperating with the locking portion to limit the resetting of the first resetter. The second resetter is arranged on the telescopic sleeve. The second resetter is suitable for cooperating with the lock to release the cooperation between the locker and the locking portion.

5. The reverse countersinking tool holder according to claim 4, characterized in that: The second resetter includes a disengagement member and a reset member, the disengagement member is slidably arranged on the telescopic sleeve, the reset member is arranged between the disengagement member and the locking portion, the disengagement member is provided with a guide portion, the locker is suitable for being engaged with the guide portion and suitable for making the disengagement member close to the locking portion, and when the disengagement member and the locking portion are in contact, the guide portion is suitable for making the locker pass through the locking portion.

6. A reverse countersinking tool holder according to claim 5, characterized in that: A locking section and a disengagement section are sequentially formed on the upper edge of the lock close to the telescopic sleeve. The length of the locking section along the axial direction of the countersinking shaft is not greater than the maximum distance between the disengagement piece and the locking portion, and the length of the disengagement section along the axial direction of the countersinking shaft is greater than the minimum distance between the disengagement piece and the locking portion.

7. The reverse countersinking tool holder according to claim 5, characterized in that: The outermost end of the guide portion protrudes from the outermost end of the locking portion; and the elastic modulus of the first resetter is smaller than the elastic modulus of the reset member.

8. The reverse countersinking tool holder according to claim 4, characterized in that: There are multiple lockers, and the lockers are arranged along the circumference of the countersinking shaft.

9. The reverse countersinking tool holder according to claim 1, characterized in that: The telescopic sleeve is provided with a step portion, and the knife edge is provided on the lower side of the step portion.

10. The reverse countersinking tool holder according to claim 1, characterized in that: A positioning groove is provided on the telescopic sleeve, and a locator is provided on the countersinking shaft. The locator and the positioning groove are slidably matched along the axial direction of the countersinking shaft. The locator and the positioning groove are suitable for limiting the movement of the telescopic sleeve in the circumferential direction of the countersinking shaft. The locator and the positioning groove are suitable for limiting the relative movement stroke of the main sleeve and the telescopic sleeve along the axial direction of the countersinking shaft.

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