KR101848262B1 - apparatus for bone profile drill - Google Patents

Abstract

Provided is a bone profile drilling device which is designed to improve accuracy in drilling an insertion path of an abutment while preventing planted fixture from being damaged. To this end, the bone profile drilling device comprises: a shank part having a mounting part which is coupled to a dental handpiece on an upper part; a drill body part connected to a lower portion of the shank part so to be rotated by rotational force of the handpiece, and having a plurality of cutting blades along an outer circumferential surface and a lower side portion; and a slip body coupled to a lower portion of the drill body part to be rotated independently so as to support rotation of the drill body part.

Description

[0001] This invention relates to an apparatus for drilling,

The present invention relates to a profile drilling apparatus, and more particularly, to a profile drilling apparatus that improves drilling accuracy with respect to an insertion path of an abutment while preventing damage to the fixture.

Generally, an implant refers to a substitute for replacing a human tissue when the original tissue is lost, and refers to implanting an artificial tooth in a dentist.

At this time, the implant may be installed in the oral cavity through a process of forming a perforation in the alveolar bone, placing the fixture, and bonding the abutment and the crown to the fixture.

Specifically, when the implant treatment position is determined, the gingival portion corresponding to the implant treatment position is removed from the inside of the mouth of the patient, and a perforation for fixing the fixture is formed in the exposed alveolar bone.

At this time, when the fixture serving as the root of the artificial tooth is inserted into the perforation, temporary teeth such as a heel abutment for preventing gums and other foreign substances from entering into the fixture when the fixture and the alveolar bone are fusion- And is coupled to a fixture.

And, when the osseointegration period of 3 ~ 6 months after the healing abutment is passed, the healing abutment is removed and the abutment is combined. At this time, the orientation of the fixture may be changed finely during the osseointegration process with the alveolar bone, and the insertion path of the abutment may be shielded by the alveolar bone and gums regenerated during the osseointegration period.

Accordingly, after the removal of the healing abutment, a process of removing the gums and alveolar bone located in the coupling path of the abutment and the fixture using the profile drill is required.

However, conventionally, the rim portion of the coupling groove on which the lower surface of the thread or abutment formed on the inner periphery of the coupling groove of the fixture is seated is damaged during the subsequent drilling through the profile drill, There is a problem that the coupling force is lowered and the combined abutment can not be accurately supported.

Further, as the profile drill is in direct contact with the fixture placed on the alveolar bone, the rotational force of the profile drill is loaded on the fixture, causing serious damage of the alveolar bone contacted with the outer surface of the fixture.

Korean Patent No. 10-1066987

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a profile drilling apparatus for improving accuracy of drilling with respect to an insertion path of an abutment while preventing the fixture from being damaged.

To achieve the above object, according to the present invention, there is provided a dental handpiece comprising: a shank portion having a mounting portion coupled to a dental handpiece at an upper end; And a plurality of cutting blades connected to a lower portion of the shank portion to be rotated by the rotational force of the handpiece, A drill body portion; And a slip body coupled to a lower portion of the drill body to be rotatable independently to support rotation of the drill body, wherein the slip body is formed of a polyether ether ketone The slip body is inserted into a guide hole of the tool body to be drilled when the drill body rotates, so that the slip body is protruded downward so as to be abutted against the inner circumference of the guide hole. And a rotary guider unit having a plurality of friction reducing grooves formed on an outer periphery thereof and protruding radially outwardly on the outer periphery of the slip body so as to be seated on an edge of the guide hole, And a guard ring portion protruding downward from a lower end of the main body portion A file drilling device is provided.

The lower surface of the drill body and the upper surface of the slip body may include a fastening protrusion and a fastening protrusion which are axially inserted and slid in the circumferential direction.

It is preferable that a tapered portion for line contact is provided on the opposed surfaces of the coupling groove portion and the coupling projection portion so that frictional force between the drill body portion and the slip body portion is reduced.

At this time, the drill body portion is provided with a support groove portion to be inserted to support the outer periphery of the guard ring portion, and the outer periphery of the upper end of the guard ring portion is radially inward so as to reduce frictional resistance between the drill body portion and the slip body portion As shown in Fig.

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Through the above solution, the present invention provides the following effects.

First, since the slip body inserted into the guide hole such as the coupling groove of the fixture and supporting the rotation of the drill body is rotated independently, the cutting position is precisely aligned with the direction and position of the guide hole at the time of drilling, The damage to the fixture and the alveolar bone can be prevented.

Secondly, since the tapered portions are formed on the opposed faces of the fastening projections and the fastening grooves, the frictional force is reduced through the line contact between the fastening protrusions and the fastening grooves, so that the rotational force transmitted to the slip body is minimized, Damage to the fixture and the alveolar bone caused by the drill can be prevented and drilling safety can be improved.

Third, when the guard ring portion having the lower end portion protruding downward from the lower end of the cutting edge forms a clearance gap between the cutting edge and the fixture when drilling, abrasion damage to the upper end portion of the fixture is prevented, The butt can be combined to be precisely matched to the top of the fixture.

1 is a perspective view of a profile drilling apparatus according to an embodiment of the present invention;
2 is a side view of the profile drilling apparatus according to an embodiment of the present invention.
3 is a rear view of the profile drilling apparatus according to an embodiment of the present invention;
4 is a cross-sectional view of the profile drilling apparatus according to an embodiment of the present invention;
5A and 5B are views illustrating a drilling process of the profile drilling apparatus according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a profile drilling apparatus according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view showing a profile drilling apparatus according to an embodiment of the present invention, FIG. 2 is a side view showing a profile drilling apparatus according to an embodiment of the present invention, FIG. 3 is a cross- FIG. 4 is a cross-sectional view of the profile drilling apparatus according to an embodiment of the present invention. FIGS. 5A and 5B are views showing the profile drilling apparatus according to an embodiment of the present invention. FIG. 7 is an exemplary view showing a drilling process. FIG.

1 to 5B, the profile drilling apparatus 100 according to the preferred embodiment of the present invention includes a shank portion 10, a drill body portion 20, and a slip body portion 30.

Herein, the profile drilling apparatus 100 of the present invention removes the healing abutment from the fixture (f) placed on the alveolar bone 1 and cuts off the abutment insertion route in the process of fastening the final abutment To remove the regenerated alveolar bone or gingival portion.

Of course, the profile drilling apparatus 100 may be used in the case of removing a gingival portion covering the upper side of the perforation (b) on the basis of a perforation (b) formed by drilling or tooth separation according to an implant procedure plan.

1 and 2, the shank portion 10 is formed in a cylindrical or hexagonal column shape to prevent warping and twisting at high speed rotation, and has a mounting portion (not shown) coupled to a dental handpiece (11) is formed.

In this case, the mounting portion 11 is provided in a D-cut shape to prevent a diaphragm from being coupled when receiving the rotational force of the dental handpiece, and a locking groove portion 11a is formed on the lower side of the mounting portion 11, The portion 11 can be securely fastened to the dental handpiece.

The drill body 20 is connected to the lower portion of the shank 10 to be rotated by the rotational force of the dental handpiece.

Here, the shank portion 10 and the drill body portion 20 may be integrally formed by cutting or the like, and each may be formed as a separate member, but may be integrally rotated.

The drill body 20 is provided in a cylindrical shape extending radially outward from the center of rotation of the shank portion 10 and has a plurality of cutting edges 21 along the outer and lower surfaces thereof.

That is, one cutting edge 21 protrudes continuously along the lower and outer circumferences of the drill body 20, and a plurality of cutting edges 21 extend in the circumferential direction of the drill body 20 Are arranged in multiple stages.

Meanwhile, the slip body 30 is coupled to the lower portion of the drill body 20 so as to rotate independently. Here, the lower part of the drill body 20 means a part opposed to the part to be drilled.

That is, in the following description, the upper and lower directions will be described with reference to the drilling state in the case where the subject to be drilled is the gingival section 2 of the mandibular alveolar ridge. When the subject to be drilled is a gingival section of the maxillary alveolar ridge, Understanding is desirable.

The slip body 30 is rotated independently of the slip body 30. The slip body 30 may be freely rotatable from the drill body 20.

That is, the slip body 30 can be rotated by the frictional force with the drill body 20 in the absence of any external force when the shank 10 rotates. However, when the external force is applied to the slip body 30, Can be maintained at a stationary state or rotated at a different speed in a direction different from the drill body 20 regardless of the rotation of the drill body 20. [

At this time, the rotation axis of the slip body 30 and the rotation axis of the drill body 20 are preferably provided in a straight line.

The slip body 30 may be coupled to a predetermined space or protrusion formed at the center of the lower surface of the drill body 20 in various manners such as magnetic coupling and hook coupling. As long as they can be independently rotated without being separated, there is no restriction on the manner of coupling each other.

At this time, when the slip body 30 is contacted with one point, the drill body 20 can be rotated with respect to the slip body 30.

That is, when the slip body 30 is inserted into the engaging groove a of the fixture f formed in the alveolar bone or the perforation b formed in the alveolar bone, Can be rotatably supported by the slip body 30. Accordingly, the cutting position by the drill body 20 can be precisely matched to the position of the fixture (f) or the hole (b).

2 to 3, the cutting edge 21 is formed at an edge of the slit body 30, which is inclined upwards in a radially outward direction along the lower surface of the drill body 20 corresponding to the outer edge of the slip body 30, A cutting edge 21a and a side cutting edge 21b extending upward from the radially outer end of the cutting edge 21a along the outer periphery of the drill body 20 and sloping radially inward toward the upper side, .

Specifically, the cutting edge 21a is formed on a lower surface of the drill body 20 and is formed to extend from a peripheral edge of the slip body 30 toward a bottom edge of the drill body 20 .

At this time, the plurality of end cutting edges 21a are radially arranged with respect to the rotation center point in the lower part of the drill body 20, and are formed to be upward slanted toward the radially outward side so as to reduce resistance upon entry to the part to be drilled desirable.

The side cutting edge 21b is formed along the outer periphery of the drill body 20 and the lower end of the side cutting edge 21b is connected to the outer edge of the cutting edge 21a.

At this time, the side cutting edge 21b has an outer profile that narrows radially inward toward the upper side from the lower end connected to the front cutting edge 21a, and has a maximum outer diameter portion to be inserted into the object to be drilled, That is, to correspond to the maximum outer diameter portion such as an abutment.

Accordingly, when drilling through the drill body 20, the contact friction area between the inner surface of the portion cut by the front cutting edge 21a and the side cutting edge 21b and the side cutting edge 21b is reduced And necrosis of living tissue such as the gingival region due to frictional heat can be minimized.

4, the lower surface of the drill body 20 and the upper surface of the slip body 30 are inserted in the axial direction and are coupled to slip in the circumferential direction, and a fastening protrusion .

Here, the fastening groove may be formed on one of the lower surface of the drill body 20 and the upper surface of the slip body 30, and the fastening protrusion may be formed on the opposite surface of the fastening groove Do.

That is, when the coupling groove 20a is formed on the lower surface of the drill body 20, the coupling protrusion 30a is formed on the upper surface of the slip body 30, The positions of the fastening protrusions can be mutually reversed.

At this time, the fastening protrusion 30a is provided in the shape of a rotating body with respect to the center line of rotation of the drill body 20 and the slip body 30, and the fastening groove 20a is formed in the fastening protrusion 30a from the outer surface profile thereof.

Accordingly, the coupling protrusion 30a can be slid in a state of being inserted into the coupling groove 20a, and the drill body 20 and the slip body 30 can rotate independently of each other.

The slip body 30 may be made of a resin material having a predetermined strength and elasticity and a high heat resistance and a low coefficient of friction and may be made of polyether ether ketone .

Accordingly, the drill body 20 can be smoothly rotated at a high speed even when the slip body 30 is fixed. When the drill body 20 rotates at high speed, the drill body 20 and / The friction heat generated between the slip body portions 30 or the distortion damage of the slip body portion 30 can be minimized.

Hereinafter, an example will be described in which the coupling groove 20a is formed on the lower surface of the drill body 20 and the coupling protrusion 30a is formed on the upper surface of the slip body 30.

The coupling groove 20a includes a hook groove 23 formed in the center of the lower surface of the drill body 20 and a support groove 22 formed in the lower end of the hook groove 23 in a radially outwardly stepped manner, .

The fastening protrusion 30a preferably includes a guard ring 32 inserted into the support slot 22 and a hook protrusion 33 protruding upward from the center of the upper surface of the guard ring 32 Do.

It is preferable that a tapered portion for line contact is provided on the opposed surfaces of the fastening groove 20a and the fastening protrusion 30a so as to reduce the frictional force between the drill body 20 and the slip body 30 Do.

Here, the tapered portion refers to a portion that is tapered or sloped such that a portion where the fastening groove 20a and the fastening protrusion 30a are in contact with each other forms a line contact.

That is, the tapered portion is understood to include the inner peripheral lower end portion 23b of the latching protrusion 23a described later, the outer peripheral upper end portion 33b of the hook projection 33a, and the outer peripheral upper end portion 32b of the guard ring portion 32 desirable.

A hook groove 23 and a hook protrusion 33 are formed on the lower surface of the drill body 20 and the upper surface of the slip body 30 to be slid in the circumferential direction. .

A hook protrusion 33 may be formed on the upper surface of the slip body 30. The hook protrusion 33 may be formed on the lower surface of the slit body 30. [

The hook protrusion 33 has an inner diameter exceeding an outer diameter of the hook protrusion 33 for smooth rotation of the hook protrusion 33 inserted in the hook protrusion 33, It is preferable that the recess is formed at a depth that is equal to the depth of the recess.

At this time, the inner periphery of the hook groove portion 23 and the outer periphery of the hook projection 33 may be provided with hooking protrusions 23a and hook protrusions 33a protruding from each other and facing each other.

The hook protrusion 23a and the hook protrusion 33a protrude from the inner circumference of the hook groove 23 and the outer circumference of the hook protrusion 33, It is preferable to straddle over the gap to the opposite surface.

In detail, the hook protrusion 33 is formed in a ring-shaped section having a hollow inside for elastic deformation, and a hook protrusion 33a protrudes radially outward from the outer circumference. A hooking protrusion 23a protrudes radially inward from the inner periphery of the hook groove 23.

At this time, the inner diameter of the hook protrusion 23a is larger than the outer diameter of the hook protrusion 33 but less than the outer diameter of the hook protrusion 33a, and the hook protrusion 33 is formed inside the groove 23 The hook protrusion 23a and the hook protrusion 33a are brought into contact with each other.

The outer peripheral upper end portion 33b of the hook projection 33a is tapered so as to be inclined upwards toward the radially inward direction. The inner peripheral lower end portion 23b of the hook projection 23a is tapered downward toward the outer side in the radial direction.

At this time, when the hook protrusion 33 is inserted into the hook groove 23, the tapered portion of the hook protrusion 33a and the tapered portion of the hook protrusion 23a come into contact with each other, And is elastically deformed radially inward.

When the hook protrusion 33a passes the hook protrusion 23a, the hook protrusion 33 is radially outwardly restored and the lower end of the hook protrusion 33a is engaged with the upper end of the hook protrusion 23a. The hook protrusion 33 and the hook groove 23 can be hooked to each other.

The distance between the radially inward end of the locking protrusion 23a and the outer circumference of the hook protrusion 33 and the distance between the radially outer end of the hook protrusion 33a and the inner circumference of the hook groove 23, (23a) and the hook projection (33a).

This minimizes the frictional force between the hook protrusion 33 and the hook groove 23 and prevents the hook protrusion 33 and the hook groove 23 from being separated from each other, .

In addition, since the tapered portions are formed at the end portions of the hook protrusion 23a and the hook protrusion 33a, hook engagement between the hook protrusion 33 and the hook groove 23 can be smoothly performed.

Further, even when the inner circumference of the hook projection 33a and the inner circumference of the hook groove 23, the outer periphery of the hook projection 23a, and the hook projection 23 are in close contact with each other, the contact portion can form a line contact, Can be minimized.

Of course, the hook protrusion 33a and the hook protrusion 23a may have a rectangular cross section in the present embodiment. However, the hook protrusion 33a may have a circular or rounded section.

The drill body 20 is provided at its lower surface with a support groove 22 into which the maximum outer diameter portion of the slip body 30 is inserted and supported.

The hook groove portion 22 is formed along the lower end of the hook groove portion 23 or the lower end portion of the hook protrusion 23a and is formed so as to have an inner diameter exceeding the inner diameter of the hook groove portion 23, desirable.

The maximum outer diameter of the slip body portion 30 means the guard ring portion 32. The guard ring portion 32 is rotatably supported on the side portion of the support groove portion 22, Lateral movement of the slip body 30 during independent rotation can be prevented without direct contact between the hook protrusions 33. [

The slip body 30 and the drill body 20 can be rotated in the same axis and the drill body 20 can be accurately rotated with respect to the slip body 30 have.

It is preferable that a tapered portion is formed on the outer peripheral upper end portion 32b of the guard ring portion 32 so as to reduce frictional force when the guard portion 22 is rotationally supported.

That is, the outer peripheral upper end portion 32b of the guard ring portion 32 is tapered so as to be spaced apart from the side portion of the support groove portion 22 and inclined radially inward toward the upper side.

At this time, the tapered portion of the guard ring portion 32 reduces the frictional force between the outer periphery of the guard ring portion 32 and the side surface portion of the support groove portion 22 as well as the frictional force between the upper end surface of the guard ring portion 32 and the upper surface of the support groove portion 22 The frictional force between the upper side step surfaces 22a can be reduced.

The distance from the upper end of the guard ring portion 32 to the lower end of the hook projection 33a is smaller than the distance from the upper end of the locking projection 23a to the upper step side surface 22a of the support groove portion 22 Preferably set.

As a result, the slip body portion 30 can be micro-flowed in the axial direction of the drill body portion 20, and the frictional resistance between the guard ring portion 32 and the support groove portion 22 can be further increased Can be reduced.

The lower part of the slip body 30 is formed to protrude downward to be inserted into guide holes a and b having no mechanism in the drilling target portion when the drill body 20 rotates, (b) is provided with a rotary guider part (31) which is held in contact with the inner periphery of the rotary guider part (b).

Here, the portion to be drilled is preferably understood to mean the upper gingival portion of the fixture (f) or the upper gingival portion of the formed perforation (b).

That is, the guide holes (a) and (b) are formed such that the engaging groove (a) in the fixture (f) formed in the alveolar bone 1 or the fixture, And a perforation (b) formed in the alveolar bone (1).

5a, at least a portion 31a of the outer periphery of the rotary guider 31 is provided in close contact with the inner circumference of the coupling groove a of the fixture f, As shown in Fig.

More specifically, when a healing abutment (not shown) is detached from the fixture f formed in the alveolar bone 1, a portion corresponding to the upper portion of the engaging groove a of the fixture f is removed The reconstructed alveolar bone or gingival region is located.

At this time, when the rotary guider 31 is inserted into the inner circumference of the coupling groove a, the drill body 20 rotates about the slip body 30 supported by the coupling groove a .

Since the drill body 20 is rotated with reference to the position of the coupling groove a of the fixture f so that the position of the alveolar bone or the gingival portion cut by the cutting edge 21 is adjusted by the fixture f, As shown in FIG.

That is, since the slip body portion 30 coupled to the lower portion of the drill body portion 20 to be independently rotated supports the rotation of the drill body portion 20 in the state where the guide holes a and b are inserted into the guide holes a and b, The cutting position through the body portion 20 is precisely matched with the position / direction of the guide holes a, b, drilling accuracy can be remarkably improved.

Accordingly, the abutment to be fastened after the removal of the healing abutment can be combined with the engaging groove (a) of the fixture (f) so that the abutment between the abutment and the fixture can be improved.

The slip body portion 30 and the drill body portion 30 are provided with tapered portions so that the slip body portion 30 is independently rotated from the drill body portion 20 and the facing surfaces of the fastening protrusion portion and the fastening groove portion are in line contact. 20 can be minimized.

Thus, the rotational force transmitted from the drill body 20 through the slip body 30 can be minimized.

That is, when the contact between the slip body 30 and the fixture f, the slip body 30, and the bore b is transmitted through the slip body 30 to the fixture f or the bore b, Can be minimized.

This can prevent damage to the inner engaging groove a or the thread s of the fixture f to which the slip body 30 is supported and damage of the alveolar bone in which the fixture f is placed, The safety can be improved and the abutment can be precisely fitted and fixed to the fixture (f) by preventing deformation of the fixture (f).

Of course, as shown in FIG. 5B, the rotary guider 31 may be directly contacted with the inside of the hole b.

Accordingly, the removal position of the gingival section for placing the integral implant or the like integrally provided with the fixture or abutment into the perforation b formed in the alveolar bone 1 is precisely matched with the formation direction / position of the perforation (b) .

It is preferable that a plurality of friction reducing grooves are formed on the outer circumference of the rotary guider 31 for line contact with the inner circumference of the guide holes a and b.

The friction reducing groove may be formed in a stepped shape or rounded. The outer periphery of the rotary guider 31 may be provided with stepped surfaces 31b and 31c by the friction reducing groove. .

At this time, it is preferable that the friction reducing groove portion is formed in consideration of the outer surface profile of the object to be implanted, such as an abutment / integral implant to be fastened or placed on the guide hole (a, b).

4 to 5A, the guard ring portion 32 is formed on the outer periphery of the slip body 30 so as to be seated on the rim of the coupling groove (a) of the fixture f, It is preferable to protrude outward in the direction. That is, the guard ring portion 32 can be formed to protrude in a size that can be seated on the rim of the guide holes a and b.

At this time, the guard ring portion 32 may protrude from the upper surface of the guard ring 21 so as to face the lower end of the cutting edge 21, but may be directly protruded from the lower edge of the cutting edge 21, It is more preferable to be provided so as not to face each other.

That is, it is preferable that the guard ring portion 32 is provided inside the radially inward end of the front cutting edge 21a, and the lower end portion protrudes downward from the lower end of the cutting edge 21.

This makes it possible to prevent the contact between the fixture (f) and the cutting edge (21) while the guard ring (32) is not in direct contact with the cutting edge (21).

In detail, the guard ring portion 32 is provided at the upper end of the rotary guider portion 31 and has an outer diameter exceeding the inner diameter of the coupling groove (a) of the fixture f.

At this time, the drill body 20 is provided with a support groove portion 22 to be inserted into the lower portion of the drill body 20 so as to support the outer periphery of the guard ring portion 32. Here, the guard ring portion 32 has a thickness exceeding a distance from the height of the upper stepped surface 22a of the support groove portion 22 to the lower end of the cutting edge 21, that is, the lowermost height of the front cutting edge 21a Respectively.

The lower end portion of the guard ring portion 32 protruded downward from the cutting edge 21 is first brought into contact with the fixture f in advance by drilling through the drill body 20, (f).

In this way, abrasion damage to the upper end of the fixture (f) can be prevented, and the subsequent fastened abutment can be coupled to accurately match the upper end of the fixture (f).

5B, in the case of removing the upper side gingival portion of the preformed bore b, the guard ring portion 32 prevents direct contact between the alveolar bone 1 and the cutting edge 21, Only the portion of the gum that is to be drilled can be accurately removed without changing the size or depth of the gum.

As described above, the slip body 30 is made of a material having a low coefficient of friction, but the frictional force of the slip body 30 and the drill body 20 to the engagement portion can be significantly reduced through the tapered portion.

The slip body 30 can be smoothly and independently rotated from the drill body 20 and the transmission of rotational force from the drill body 20 toward the slip body 30 can be blocked have.

Thus, damage to the fixture (f) due to the slave rotation of the slip body (30) when the drill body (20) is rotated can be prevented, and drilling safety and accuracy can be improved.

As described above, the present invention is not limited to the above-described embodiments, and variations and modifications may be made by those skilled in the art without departing from the scope of the present invention. And these modifications fall within the scope of the present invention.

1: alveolar bone 2: gums
10: shank portion 20: drill body portion
30: Slip body part 100: Profile drilling device

Claims (5)

A shank portion provided at an upper end thereof with a mounting portion coupled to the dental handpiece;
And a plurality of cutting blades connected to a lower portion of the shank portion to be rotated by the rotational force of the handpiece, A drill body portion; And
And a slip body coupled to the lower portion of the drill body to be independently rotated to support rotation of the drill body,
The slip body is made of polyether ether ketone (PEEK) so as to reduce frictional heating during high-speed rotation of the drill body,
And a plurality of friction reduction grooves formed on the outer circumference of the slip body so as to be in line contact with the inner circumference of the guide hole so as to be contacted and supported by the guide hole of the tool to be drilled when the drill body rotates A rotary guider unit is provided,
And a guard ring portion protruding radially outward to be seated on an edge of the guide hole and protruding downward from a lower end of the cutting edge to prevent contact between the fixture and the cutting edge, Profile drilling device. The method according to claim 1,
Wherein the drill body portion and the slip body portion have a coupling groove portion and a coupling projection portion which are inserted in the axial direction and slip in the circumferential direction, respectively. 3. The method of claim 2,
Wherein a tapered portion for line contact is provided on an opposing surface of the coupling groove portion and the coupling projection so that frictional force between the drill body portion and the slip body portion is reduced. delete The method according to claim 1,
The drill body has a support groove portion to be inserted into a lower portion of the drill body to support the outer periphery of the guard ring portion,
Wherein the outer periphery of the upper end of the guard ring portion is radially inwardly tapered so as to reduce frictional resistance between the drill body and the slip body.

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