KR20110118021A - Removal driver for post screw to remove post screw - Google Patents

Abstract

A post screw and a remover driver for a post screw for removing it are disclosed. A post screw remover driver for removing the post screw of the present invention comprises: a driver body; And a coupling tool provided at one side of the driver body and partially engaged with an engagement groove formed in the screw head portion of the post screw to release the post screw from the fixture, wherein a portion of the coupling tool distributes the stress. It is characterized in that the area of the cross section intersecting the longitudinal direction of the coupling tool is formed to gradually increase toward the driver body. According to the present invention, it is possible to fit the post screw and the remover driver tightly to each other when the post screw for removing the abutment from the fixture using the remover driver to separate the abutment from the fixture, and to the remover driver. By distributing the transmitted stress, the stress can be reduced, thereby preventing the breaker driver from being broken, and the abutment can be quickly separated.

Description

Removal driver for post screw to remove post screw}

According to the present invention, it is possible to fit the post screw and the remover driver tightly to each other when the post screw is removed from the fixture by using the remover driver to separate the abutment from the fixture, and to the remover driver. The present invention relates to a post screw remover driver for removing the abutment and a post screw for removing the abutment, while preventing stress breakage by dispersing the stresses.

Implants are originally meant to be a substitute for recovery when tissue is lost, but in dentistry, implants are made of artificial teeth. In order to replace the lost root (root), a tooth root made of titanium (titanium), which is not rejected by the human body, is planted in the alveolar bone where the tooth falls out, and the artificial tooth is fixed to restore the function of the tooth.

In the case of general prosthetics or dentures, the surrounding teeth and bones are damaged over time, but the implants do not damage the surrounding dental tissues, and they have the advantage that they can be used semi-permanently because they have the same function or shape as natural teeth and do not cause tooth decay.

Implants also enhance the function of dentures and improve the aesthetic aspects of dental prosthetic restorations, as well as in single brace restorations, as well as in partial and complete teeth. Furthermore, it disperses excessive stress on surrounding supportive bone tissue and helps stabilize teeth.

Briefly, the implant procedure is determined in the alveolar bone where the tooth is lost, and after fixing the implant to replace the root (root), abutment is applied to the fixture. After bonding, the artificial tooth is fixed to the abutment with adhesive.

On the other hand, the abutment bonded to the fixture may be fractured after a certain amount of time after the implant procedure or after the implant procedure.If the abutment is broken during the implant procedure, it is difficult to fix the artificial tooth. If the abutment fractures after a period of time, the abutment will break away and the abutment needs to be replaced quickly.

Briefly describing the process of replacing the broken abutment, the abutment is coupled to the fixture by a post screw. A part of the post screw is fastened to the inside of the fixture and the other part is fastened to the abutment so that the post screw is not apparent in appearance. A remove driver is required to remove the post screw.

When the operator inserts the remover driver into the abutment part and engages with the post screw, and then rotates the remover driver, the post screw fastened to the fixture is released from the fixture and the abutment can be detached from the fixture.

Looking at the conventional method of combining the remover driver and the post screw, first of all adopts a screw fastening method for fastening the remover driver and the post screw. In this case, a male thread is formed on one side of the remover driver, and the remover driver is combined. A female thread corresponding to one side of the post screw is formed on the inner wall surface of the fastening groove, and is coupled to each other by screwing them.

However, in the case of such a coupling method, if the fastening direction of the remover driver and the post screw are fastened to the fixture, the remover driver cannot release the post screw. Therefore, the fastening direction of the remover driver and the post screw should be designed to be reversed. Mistakes in the direction of tightening in the design or manufacturing process may increase manufacturing costs or reduce productivity.

Secondly, when a wrench portion is formed on one side of the remover driver in the form of a hexagon wrench, and a wrench groove corresponding to the above-described wrench portion is formed on the post screw to which one side of the remover driver is coupled, they are engaged to release the post screw. Can be.

However, this coupling method is not easy to fit the remover driver and the post screw, and there is no force to fix them except the screwdriver and the wrench combination of the remover screwdriver, so the remover driver when rotating the remover driver to release the post screw The wrench part is constantly stressed, which causes a problem that the remover driver is broken, which causes additional problems such as an increase in cost due to the additional manufacture of the remover driver and a rapid replacement of the abutment.

An object of the present invention is to use a remover screwdriver to remove the post screw to fasten the abutment and the fixture to separate the abutment from the fixture, the interference fit between the post screw and the remover driver is possible, the remover driver The present invention provides a post screw remover driver for removing the abutment and a post screw to remove the abutment while preventing the breaker driver from being damaged by dispersing the stress transmitted to the remover.

The object is, according to the present invention, a driver body; And a coupling tool provided at one side of the driver body and partially engaged with an engagement groove formed in the screw head portion of the post screw to release the post screw from the fixture, wherein a portion of the coupling tool is provided. The area of the cross section intersecting the longitudinal direction of the coupling tool is distributed by the remover driver for post screw, characterized in that it is formed gradually increasing toward the driver body.

The coupling tool, the wrench portion is formed along the longitudinal direction of the coupling tool at the front end, the cross section intersecting the longitudinal direction is formed in the shape of a polygonal wrench; And a tapered portion connected to the wrench portion and having a taper formed to gradually increase an area of a cross section crossing the longitudinal direction toward the driver body.

The coupling tool may further include a threaded portion spaced apart from the tapered portion and having a thread formed along a length direction of the coupling tool.

The tapered portion may be formed between an angle of 3 ° to 7 ° inclination angle of one side of the longitudinal section of the tapered portion.

The inclination angle of the tapered portion may be 5 °.

The wrench portion may have a hexagonal cross section.

It may further include a handle provided on the other side of the driver body opposite to the coupling tool to rotate the driver body and the coupling tool.

The handle may further include a coupling protrusion protruding from one side opposite to the driver body to be coupled to a separate tool.

The object is, according to the present invention, a screw body; And a screw head provided on one side of the screw body and having an engaging groove formed to partially engage with a coupling tool of a remover driver, wherein the screw head is disposed on an inner circumferential surface of the engaging groove toward the screw body at a front end surface thereof. A screw taper portion having a taper formed therein so as to gradually reduce an area of a cross section crossing the longitudinal direction of the engagement groove; And a wrench groove portion connected to the screw taper portion and engaged with the wrench portion of the remover driver coupling tool.

The inclination angle of the screw taper may be formed between an inclination angle of one side of the cross section in the longitudinal direction of the screw taper between 3 ° and 7 °.

The angle of inclination of the screw taper may be 5 °.

The wrench groove portion may have a polygonal cross section that crosses the wrench groove portion in a longitudinal direction.

The cross section may be hexagonal.

A screw thread may be formed along the longitudinal direction of the screw body on the outer circumferential surface of one side of the screw body opposite to the screw head.

In order to fully understand the present invention, the operational advantages of the present invention, and the objects achieved by the practice of the present invention, reference should be made to the accompanying drawings which illustrate preferred embodiments of the present invention and the contents described in the accompanying drawings.

According to the present invention, it is possible to fit the post screw and the remover driver to be in close contact with the remover driver when removing the post screw which fastens the abutment and the fixture together to remove the abutment from the fixture. By distributing the transmitted stress, the stress can be reduced, thereby preventing the breaker driver from being broken, and the abutment can be quickly separated.

1 is a perspective view of a remover driver for a post screw according to an embodiment of the present invention.
FIG. 2 is a front view of the remover driver for the post screw according to FIG. 1. FIG.
3 is a perspective view of a post screw according to an embodiment of the present invention.
4 is a cross-sectional view of the post screw according to FIG. 3.
5 and 6 is a detailed view of the coupling of the post screw and the post screw remover according to an embodiment of the present invention.

In order to fully understand the present invention, the operational advantages of the present invention, and the objects achieved by the practice of the present invention, reference should be made to the accompanying drawings which illustrate preferred embodiments of the present invention and the contents described in the accompanying drawings.

Hereinafter, the present invention will be described in detail by explaining preferred embodiments of the present invention with reference to the accompanying drawings. Like reference numerals in the drawings denote like elements.

1 is a perspective view of a remover driver for a post screw according to an embodiment of the present invention, Figure 2 is a front view of the remover driver for a post screw according to Figure 1, Figure 3 is a post screw according to an embodiment of the present invention 4 is a cross-sectional view of a post screw according to FIG. 3, and FIGS. 5 and 6 are detailed views of a post screw and a post screw remover according to an embodiment of the present invention.

1 and 2, as shown in these drawings, the remover driver 100 for a post screw according to the present embodiment is provided on the driver body 110 and on one side of the driver body 110 and is a fixture. Coupling tool 130 and the coupling tool 130 is partially engaged with the engaging groove 231 formed in the screw head 230 of the post screw 200 to release the post screw 200 from the (F); It is provided on the other side of the driver body 110 that is opposite to the driver body 110 and a handle 150 for rotating the coupling tool 130.

First, looking at the driver body 110, the driver body 110 is formed in a relatively long cylindrical shape than the coupling tool 130. In this embodiment, the driver body 110 is provided in a cylindrical shape, but the shape of the driver body 110 is not limited thereto, but may be formed in various forms, considering that the remover driver 100 is used in a human mouth. Cylindrical without corners is preferred.

The coupling tool 130 and the handle 150 are provided on both sides of the cylindrical driver body 110. The coupling tool 130 provided adjacent to one side of the driver body 110 is also formed in a cylindrical shape similar to the driver body 110. The size of the cross section crossing in the longitudinal direction of the coupling tool 130 is the length of the driver body 110. It is formed smaller than the size of the cross section that crosses the direction, the length of the coupling tool 130 is formed relatively short to the length of the driver body (110).

Looking at the coupling tool 130 in more detail, the coupling tool 130 is a wrench portion 131 formed from the tip of the coupling tool 130 opposite to the driver body 110, the tapered portion 133 and the screw portion 135 ).

Here, the wrench portion 131 and the taper portion 133 of the coupling tool 130 may be a wrench groove portion 231b and a screw taper portion of the engaging groove 231 formed in the screw head 230 of the post screw 200 to be described later. 231a).

As described above, the coupling tool 130 and the post screw 200 may be coupled by screwing. In this case, the thread is formed on the coupling tool 130 and the post screw 200 is also fastened to the fixture F. The thread may be formed, but in the case of such screw fastening, confusion may occur in the fastening direction of the coupling tool 130 and the fastening direction of the post screw 200. The wrench portion 131 and the tapered portion 133 are formed to be engaged with the post screw 200 so that the interference fit between the 130 and the post screw 200 is possible.

First, the wrench part 131 is formed by a predetermined length along the longitudinal direction of the coupling tool 130 from the distal end of the coupling tool 130 opposite to the driver body 110 and crosses the longitudinal direction of the coupling tool 130. The cross section is formed in the shape of a wrench having a polygon. Wrench portion 131 in the present embodiment has a hexagonal cross section, but the shape of the cross section is not limited to this may be provided in the form of various polygons, such as square or octagon, depending on the operator or procedure characteristics.

Next, the tapered portion 133 is connected to the wrench portion 131 and has a tapered shape in which the area of the cross section that crosses the longitudinal direction of the coupling tool 130 toward the driver body 110 gradually increases.

When the inclination angle θ 'of the tapered portion 133 is determined by the longitudinal cross section of the coupling tool 130, the inclination angle θ ′ of one side is formed between an angle of 3 ° to 7 °. The taper portion 133 enables an interference fit where the post screw 200 and the remover driver 100 are in close contact with each other when the post screw 200 is removed by using the remover driver 100, and the remover driver 100 is attached to the remover driver 100. By distributing the stress to be transmitted can reduce the stress is provided to prevent breakage of the remover driver (100).

However, when the inclination angle θ 'of the tapered portion 133 is greater than the aforementioned angle 7 °, the thickness of the top of the screw head 230 of the post screw 200 becomes thin, so that the screw head 230 is raised or the taper is tapered. If the inclination angle θ 'of the tapered portion 133 is smaller than the above-described angle 3 °, there is a problem in that the machining becomes difficult, so the inclination angle θ' is increased. In this embodiment, the inclination angle θ 'of the tapered portion 133 is 5 °, and the sum of the inclination angles θ' of both sides is 10 °. To form.

Next, on one side of the tapered portion 133, that is, the side opposite to the wrench portion 131, a screw 135 having a thread formed in the longitudinal direction of the coupling tool 130 is provided to be spaced apart from the tapered portion 133.

Screw portion 135 is a fastening portion formed in the abutment (A) the screw portion 135 formed in the remover driver 100 as shown in detail in Figure 6 when the operator is difficult to separate the abutment (A) by hand directly The abutment A can be separated from the fixture F by engaging with A1.

On the other hand, the other side of the driver body 110, that is, one side of the driver body 110 opposite to the side on which the coupling tool 130 is provided is provided with a handle 150 that allows the operator to rotate the remover driver 100. . The handle 150 has a cross section that is relatively larger than the cross section of the driver body 110 and its length is formed in a cylindrical shape that is relatively shorter than the driver body 110.

And the handle 150 has a non-slip protrusion 153 to prevent the handle 150 from slipping in the operator's hand when the operator grasps the handle 150 and rotates the remover driver 100 of the handle 150 A plurality of the outer peripheral surface is formed along the radial direction of the handle 150.

In addition, one side of the handle 150, which is opposite to the driver body 110, is further formed with a coupling protrusion 151 protruding from the surface, the coupling protrusion 151 to rotate the remover driver 100 Where the operator is difficult to directly rotate the remover driver 100 is a separate tool, for example a separate tool such as a wrench is combined.

In this embodiment, the shape of the cross section intersecting the longitudinal direction of the coupling protrusion 151 is formed in a square, the shape of the cross section of the coupling protrusion 151 is similar to the wrench portion 131 of the coupling tool 130 described above. The shape of the cross section is not limited to the rectangle but may be provided in the form of various polygons.

3 and 4 illustrate a post screw 200 that can engage the coupling tool 130 of the remover driver 10 to selectively release it from the fixture F. The post screw 200 is fixed. It is disposed between the chew (F) and the abutment (A) to serve to fasten the fixture (F) and the abutment (A).

3 and 4, as shown in these drawings, the post screw 200 is provided at one side of the screw body 210 and the screw body 210, and at least a portion of the remover driver 100 is engaged. It includes a screw head 230 is formed that the engaging groove 231 can be.

First, referring to the screw body 210 of the post screw 200, the screw body 210 in the present embodiment is formed in the same cylindrical shape as the driver body 110 of the remover driver 100 of the screw body 210 The shape is not limited to the cylindrical shape in the present embodiment and may be formed in various shapes.

The screw body 210 is a post screw 200 is disposed between the fixture (F) and the abutment (A) to fasten the fixture (F) and the abutment (A) when the post screw 200 is a fixture ( A thread 211 that can be fastened to a thread formed in the inside of F) is formed along the longitudinal direction of the screw body 210 on one side of the outer circumferential surface of the screw body 210.

In addition, the screw head 230 having an engaging groove 231 to which at least a portion of the remover driver 100 is engaged may be engaged on the side opposite to the one side on which the screw 211 is formed in the screw body 210. Prepared.

The screw head 230 is formed in a cylindrical shape similar to the screw body 210, and the size of the cross section crossing in the longitudinal direction of the screw head 230 is relatively larger than the size of the cross section crossing in the longitudinal direction of the screw body 210. It is formed in a cylindrical shape, the length of the screw head 230 is formed relatively shorter than the length of the screw body 210.

An engagement groove 231 is formed on one side of the screw head 230, that is, the upper end of the screw head 230, as described above, and the engagement groove 231 is a screw body 210 along a central axis of the screw head 230. Toward a predetermined depth.

In addition, the engaging groove 231 has a screw taper portion 231a which may be engaged with the wrench groove portion 231b and the tapered portion 133 that are engaged with the wrench portion 131 of the remover driver coupling tool 130. Prepared.

As the area of the cross section of the engaging groove 231 crossing the longitudinal direction of the screw head 230 downwards by a predetermined length from the upper surface of the screw head 230 in which the engaging groove 231 is formed is directed toward the screw body 210. A taper-shaped screw taper portion 231a that gradually decreases is formed.

Subsequently, a wrench groove portion 231b connected to the screw taper portion 231b and having a polygonal cross section of the engagement groove 231 is formed.

The screw taper portion 231a is a portion that is engaged with the taper portion 133 of the coupling tool 130 when the coupling tool 130 of the remover driver 100 is engaged with the engagement groove 231. 231a and the taper portion 133 are engaged with each other, thereby allowing an interference fit in which the post screw 200 and the remover driver 100 are in close contact with each other, and distributing the stress transmitted to the remover driver 100 to stress the stress. Can be reduced.

The inclination angle θ ″ of the screw taper portion 231a is formed to be the same as the inclination angle θ ′ of the taper portion 133 of the remover driver 100. The inclination angle θ ″ of the screw taper portion 231a. ) Is determined from the longitudinal cross section of the screw taper 231a so that one side tilt angle θ ″ is formed between 3 ° and 7 ° angle. In this embodiment, the one side tilt angle θ ″ is particularly preferable. ) Is set to 5 ° so that the sum of the inclination angles θ " on both sides is 10 °.

As such, when the inclination angle θ ″ of the screw taper 231a is formed to be the same as the inclination angle θ ′ of the taper 133 of the remover driver 100, the engagement tool 130 and the engagement groove 231 are formed. The taper portion 133 is forcibly fitted to the screw taper portion 231a when the coupling is engaged, thereby increasing the coupling force between the remover driver 100 and the post screw 200.

The wrench groove portion 231b connected to the screw taper portion 231a has a polygonal cross section that crosses the longitudinal direction of the engagement groove 231 similarly to the wrench portion 131 of the remover driver coupling tool 130.

Since the wrench groove 231b is engaged with the wrench 131 of the remover driver 100, the cross section of the wrench groove 231b is formed to correspond to the shape of the cross section of the wrench 131.

Therefore, in the present embodiment, since the wrench portion 131 of the remover driver 100 has a hexagonal cross section, the wrench groove portion 231b of the post screw 200 is also formed in a hexagonal cross section.

Hereinafter, a method of using a post screw and a post screw remover driver according to the present embodiment will be described with reference to the accompanying drawings.

5 and 6, after forming a hole in the alveolar bone, a fixture F installed to replace the root may be combined with the abutment A capable of fixing the artificial tooth. At this time, it is provided to fasten the fixture (F) with the abutment (A) as a post screw 200, the post screw 200 is disposed between the fixture (F) and the abutment (A) to fix the fixture (F) ) And abutment (A).

On the other hand, one side of the fixture (F) is formed with an insertion groove (F1) so that a portion of the abutment (A) can be inserted into the fixture (F), the insertion groove (F1) is one side line of the fixture (F) Is formed along the longitudinal direction of the fixture (F) from the cross-section, the area of the cross section that crosses the longitudinal direction of the fixture (F) is formed while gradually decreasing, the insertion groove (F1) in the interior of the fixture (F) Is connected to the screw fastening portion (F2) is further formed that the thread 211 of the post screw 200 can be fastened.

On the other hand, when the abutment (A) is broken for the fixture (F) and the abutment (A) as described above and the replacement is necessary, the abutment (A) is not easily removed from the fixture (F). There is a need for a remover driver 100 to separate it from the fixture F.

When the remover driver 100 of the present embodiment needs to be replaced due to the fracture of the abutment A, a part of the remover driver 100, that is, the coupling tool 130 of the remover driver 100 is posted through the abutment A. Engagement coupling to the engagement groove 231 formed in the screw head 230 of the screw 200.

Here, the wrench portion 131 of the coupling tool 130 is engaged with the wrench groove portion 231a of the engagement groove 231, and the tapered portion 133 formed by being connected to the wrench portion 131 is connected to the wrench groove portion 231a. It is engaged with the screw taper portion 231b formed by being connected.

At this time, the inclination angle θ ″ of the screw taper 231b is formed at 10 °, and the inclination angle θ ′ of the tapered part 133 is also formed at 10 ° so that the inclination angle θ of the tapered part 133 is formed. ') Is formed to be equal to the inclination angle θ " of the screw taper portion 231b, so that the taper portion 133 is engaged with the screw taper portion 231b by an interference fit, thereby providing a greater coupling force than a general engagement coupling force. Will have

As such, when the coupling tool 130 of the remover driver 100 is engaged with the engagement groove 231 formed in the screw head 230 of the post screw 200, the operator may handle the handle 150 provided in the remover driver 100. The remover driver 100 is rotated to release the thread 211 of the post screw 200 fastened to the screw fastening portion F2 of the fixture F.

The post screw 200 may be removed using the coupling force of the remover driver 100 and the post screw 200, and the abutment A may be separated from the fixture F. FIG.

During this process, the wrench part 131 formed on the coupling tool 130 of the remover driver 100 is subjected to stress, and the taper part 133 connected to the wrench part 131 is transmitted to the remover driver 100. By dispersing the stress, an effect of reducing the stress received by the wrench unit 131 may be obtained.

In addition, the remover driver 100 may directly rotate the operator using the handle 150, but if the operator is difficult to directly rotate the remover driver 100, the remover driver 100 may be additionally provided to the coupling protrusion 151 provided in the remover driver 100. The remover driver 100 may be rotated by connecting a tool.

When the post screw 200 and the post screw remover driver 100 are used, the remover 100 is removed from the fixture F to replace the broken abutment A. The formed taper portion 133 and the screw taper portion 231a of the post screw 200 enable an interference fit in which the remover driver 100 and the post screw 200 are in close contact with each other, and are transferred to the remover driver 100. Since the stress is dispersed, it is possible to reduce the stress of the remover driver 100, in particular, the wrench 131, thereby preventing breakage of the remover driver 100, thereby increasing the service life and further replacing the abutment A. You can get the effect quickly.

In addition, as shown in FIG. 6, when the abutment A is detached from the fixture F after the post screw 200 is released from the fixture F, the operator directly removes the abutment A by the fixture ( When it is difficult to separate from the F), the screw portion 135 formed on the coupling tool 130 of the remover driver 100 is directly coupled to the fastening portion A1 formed in the abutment A, and then the abutment ( A) can be separated from the fixture (F).

As described above, the present invention is not limited to the described embodiments, and various modifications and changes can be made without departing from the spirit and scope of the present invention, which will be apparent to those skilled in the art. Therefore, such modifications or variations will have to be belong to the claims of the present invention.

F: fixture A: renter
100: remover driver for the post screw 110: driver body
130: coupling tool 131: wrench
133: taper portion 135: screw portion
150: handle 151: engaging projection
153: non-slip protrusion 200: post screw
210: screw body 211: thread
230: screw head 231: engagement
231a: screw taper portion 231b: wrench groove portion

Claims (14)

Driver body; And
A coupling tool provided on one side of the driver body and partially engaged with an engaging groove formed in the screw head of the post screw to release the post screw from the fixture,
And a portion of the coupling tool is formed with a gradual increase in area of the cross section intersecting the longitudinal direction of the coupling tool toward the driver body to disperse stress. The method of claim 1,
The coupling tool,
A wrench portion formed at a distal end along the longitudinal direction of the coupling tool and having a cross section crossing the longitudinal direction in the shape of a polygonal wrench; And
And a tapered portion connected to the wrench portion and having a tapered portion to gradually increase an area of a cross section crossing in the longitudinal direction toward the driver body. The method of claim 2,
The coupling tool,
And a threaded portion provided spaced apart from the tapered portion, the threaded portion being formed along the longitudinal direction of the coupling tool. The method of claim 2,
The taper portion is a post screw remover driver, characterized in that the inclination angle of one side of the longitudinal section of the tapered portion is formed between the angle of 3 ° to 7 °. The method of claim 5,
The tilt angle of the tapered portion is a post screw remover driver, characterized in that 5 °. The method of claim 2,
The wrench unit is a post screw remover driver, characterized in that the cross section is formed in a hexagon. The method of claim 1,
And a handle provided on the other side of the driver body opposite to the coupling tool to rotate the driver body and the coupling tool. The method of claim 7, wherein
The handle of the post screw remover driver, characterized in that the handle is further formed to protrude from one side opposite to the driver body to be coupled to a separate tool. Screw body; And
It includes a screw head is provided on one side of the screw body is formed in the engaging groove is partially engaged with the coupling tool of the remover driver,
The screw head,
A screw taper portion formed on an inner circumferential surface of the engagement groove toward the screw body at a front end surface thereof, the taper being tapered to gradually reduce an area of a cross section crossing in the longitudinal direction of the engagement groove; And
And a wrench groove portion connected to the screw taper portion and engaged with the wrench portion of the remover driver coupling tool. 10. The method of claim 9,
The inclination angle of the screw taper portion is a post screw, characterized in that the inclination angle of one side of the longitudinal cross section of the screw taper portion is formed between the angle of 3 ° to 7 °. The method of claim 10,
The inclination angle of the screw taper portion is a post screw, characterized in that 5 °. 10. The method of claim 9,
The wrench groove portion is a post screw, characterized in that the cross section that crosses the longitudinal direction of the wrench groove portion is formed in a polygon. The method of claim 12,
The cross section is a post screw, characterized in that the hexagon. 10. The method of claim 9,
Post screw, characterized in that the thread is formed along the longitudinal direction of the screw body on the outer circumferential surface of one side of the screw body opposite to the screw head.

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