JP2003194033A - Locking structure and locking method for check screw - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a check screw locking structure and a locking method for surely securing a check screw screwed in a threaded hole. <P>SOLUTION: The locking structure A for the check screw is constructed to engage a leading end 31 (one end) of a helix 30 or a helical wire screwed in the threaded hole 4 with the check screw 20 screwed in the threaded hole 4 so that, when torque in a direction of loosening is caused on the check screw 20, the torque in the loosening direction acts on the leading end 31 of the helix 30 and the helix 30 makes to increase in diameter to prevent turning of the helix 30 and the check screw 20. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a set screw slack prevention structure and a slack prevention method for fixing a set screw in a screw hole.

[0002]

2. Description of the Related Art Conventionally, in the manufacture of products by casting,
In order to form a hole portion such as a screw hole in a product, as shown in FIG. 4, the casting pin 2 is inserted into the mold 1 to project into the cavity 3, and the casting pin 2 is cast out. By that,
The product has holes. At this time, in order to fix the casting pin 2 to the mold 1, a back block 5 through which a screw hole 4 corresponding to the casting pin 2 penetrates is provided on the outside of the mold 1, and the screw hole is inserted from the outside of the back block 5. After inserting the spacer pin 40 into 4, set screws 20 ', 30'
Are sequentially screwed in and fastened. That is, after fastening the first set screw 20 'to the screw hole 4, the second set screw 3
By fastening 0'to the first set screw 20 ',
There is a set screw loosening prevention structure A'which tries to fix the first set screw 20 'and the second set screw 30' to each other by fixing them in the screw hole 4.

[0003]

However, in the conventional set screw loosening prevention structure A ', the fastening force between the set screw 20' and the set screw 30 'cannot be said to be sufficient, and therefore the following problems exist. Was. The heat of the high-temperature molten metal filled in the cavity 3 is transferred to the casting pin 2 and the spacer pin 40, so that the casting pin 2 and the spacer pin 40 are thermally expanded and reduced when cooled after casting. By repeating expansion and contraction of the cast pin 2 and the spacer pin 40, the first set screw 20 ′ and the spacer pin 4 are
A gap occurs between 0. Also, a gap is generated by pressure or vibration when the molten metal is injection molded. That is, a gap is generated in the tightening direction of the first set screw 20 '. Then, the first set screw 20 'is loosened toward the gap side, the fastening force between the first set screw 20' and the second set screw 30 'is reduced, and the set screw 20', due to the vibration of the mold 1 or the like, 30 '
There is a problem that slack occurs in the.

Therefore, the present invention has been made to solve the above problems, and provides a slack preventing structure and a slack preventing method for a set screw, which can surely fix a set screw screwed into a screw hole. The challenge is to provide.

[0005]

The present invention is constructed to solve the above-mentioned problems, and the invention according to claim 1 is a structure for preventing loosening of a set screw, which is screwed into a screw hole. One end of the spiral, which is a spiral wire rod, is engaged with the set screw screwed into the screw hole, and when torque in the slack direction is generated in the set screw, one end of the spiral is The torque is generated in the slack direction, and the spiral body tries to expand its diameter, so that the spiral body and the set screw are prevented from rotating.

Here, the shape and material of the wire material forming the spiral is not limited, such as the cross-sectional shape and the number of turns. Further, as the spiral body, an existing helisert in which a wire rod having a rhombic cross-section is spirally formed and a groove formed on the inner peripheral surface thereof is used as a female screw may be used.

Further, the spiral body screwed into the screw hole is stationary within the screw hole due to the frictional force between the outer peripheral surface of the spiral body and the inner peripheral surface of the screw hole, and the spiral body is loosened at one end of the spiral body. When torque is generated, one end side rotates ahead of the other end side where torque is not generated and rotates in the slack direction, and one end of the spirally formed wire rod moves outward. The spiral body tries to expand in the screw hole because it deforms so as to expand.

According to the present invention, when the set screw screwed into the screw hole rotates in the loosening direction, the spiral body engaged with the set screw is pressed against the inner peripheral surface of the screw hole in order to expand the diameter.
Since the frictional force between the outer peripheral surface of the spiral body and the inner peripheral surface of the screw hole is increased, it is possible to prevent the set screw from loosening.

Further, the invention according to claim 2 is a set screw loosening prevention structure using a set screw and a spiral body for preventing the set screw from loosening by being screwed into the screw hole together with the set screw. Then, the spiral body is formed in a spiral shape so that the wire rod is screwed into the screw hole, and both ends of the wire rod are bent inside the spiral body so as to be perpendicular to the axial direction of the spiral body, and face each other. The other end of the wire rod is configured to be out of phase with the one end of the wire rod in the tightening direction, and the set screw has a spiral body engagement with which one end of the spiral body can engage. Is formed, and the spiral body and the set screw are screwed into the screw hole in a state where one end portion of the spiral body is engaged with the spiral body engaging portion.

Here, when a torque in the slack direction is generated at the other end of the spiral body, the spirally formed wire rod is deformed so as to be narrowed inward and the entire spiral body is reduced in diameter.

According to the present invention, by rotating the other end portion, which is out of phase with the one end portion in the tightening direction, in the slack direction to be in a parallel state, one end portion of the spiral body is formed. Since a torque is generated in the slack direction and the diameter of the entire spiral body is reduced, the outer diameter of the spiral body can be easily adjusted.

The invention described in claim 3 is the same as claim 1
Alternatively, the set screw loosening prevention structure according to claim 2 is characterized in that the wire rod is elastically deformable, and the outer diameter of the spiral body is formed larger than the inner diameter of the screw hole.

According to the present invention, since the spiral body that has been reduced in diameter and screwed into the screw hole tries to expand the diameter by its elastic force, the spiral body is always pressed against the inner peripheral surface of the screw hole. The rotation of the spiral body screwed into the screw hole can be reliably prevented.

The invention according to claim 4 is the same as claim 1.
The structure for preventing loosening of a set screw according to any one of claims 1 to 3, wherein the spiral body is screwed into the screw hole while being fitted onto a part of the set screw.

According to the present invention, the overall length in the axial direction of the set screw and the spiral body screwed into the screw hole can be shortened.

According to a fifth aspect of the present invention, a set screw, a spiral body for preventing the set screw from loosening by being screwed into the screw hole together with the set screw, and the set screw and the spiral body are attached to the screw hole. A method for preventing loosening of a set screw using an installation tool and an auxiliary installation tool, wherein a spiral body is formed in a spiral shape so that an elastically deformable wire rod is screwed into a screw hole, and both ends of the wire rod are spiral members. It is bent inside the spiral so as to be perpendicular to the axial direction of
The other end of the wire rod is configured to be out of phase with the one end of the wire rod in the tightening direction, and the set screw has a spiral body engagement with which one end of the spiral body can engage. A part is formed, and an auxiliary tool engaging part capable of engaging with a mounting auxiliary tool is formed at the other end, and the mounting tool has a shaft part having an outer diameter smaller than the inner diameter of the spiral body. An engaging groove is formed at the tip of the so that both ends of the wire of the spiral body can be engaged, and (1) one end of the wire of the spiral body is connected to the spiral body of the set screw. First step of engaging the mating portion, and (2) engaging the mounting auxiliary tool with the auxiliary tool engaging portion of the set screw, and engaging the engaging groove of the mounting tool with the other end of the wire rod of the spiral body. Then, while the rotation of the set screw is locked by the mounting auxiliary tool, stop the mounting tool while twisting the mounting tool in the loosening direction of the set screw. The second step of pushing it toward the screw and engaging one end of the wire rod of the spiral with the engaging groove of the mounting tool, and (3) using the mounting tool, rotate the set screw and the spiral integrally to form a screw hole. It is characterized by including a third step of screwing in, and (4) a fourth step of pulling out and removing the mounting tool from the spiral body.

According to the present invention, both ends of the wire rod of the spiral body are engaged in parallel with each other in the engaging groove of the mounting tool, and in this state, the mounting tool is engaged with the set screw to rotate. The spiral body can be easily screwed together with the set screw in a reduced diameter state. Also, after the set screw and the spiral body are screwed in, by pulling out and removing the mounting tool from the spiral body, the parallel state of both ends of the wire is released, and the elastic force of the wire expands the diameter of the spiral body. Can be pressed against the inner surface of the.

Therefore, according to the loosening prevention structure and the loosening prevention method of the set screw of the present invention, the spiral body screwed into the screw hole is pressed against the inner peripheral surface of the screw hole to expand the diameter, and the frictional force causes the spiral body to rotate. By preventing the locking screw from loosening, the locking screw engaged with the spiral body can be prevented, so that the locking screw can be securely fixed in the screw hole.

[0019]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

The set screw loosening prevention method and set screw according to the embodiment of the present invention can be applied to set screws screwed into various screw holes, but in this embodiment, a hole is formed in a product during casting. An example will be described in which the cast pin to be formed is applied to a set screw for fixing to the mold.

FIG. 1 is a side sectional view showing a loosening prevention structure for a set screw according to an embodiment of the present invention. 2A and 2B are views showing respective constituent elements in the loosening prevention structure of a set screw according to the embodiment of the present invention, FIG. 2A is a perspective view showing a set screw, and FIG. 2B is a perspective view showing a spiral body, (C) is a perspective view showing a mounting tool. 3A and 3B are views showing a method for preventing loosening of a set screw according to an embodiment of the present invention, in which FIG. 3A is a side view showing a helical diameter reducing step, and FIG. 3B is a deformed state of the helical body in the helical diameter reducing step. FIG. 6C is a side view showing a screwing step, and FIG. 8D is a view showing a deformed state of the spiral body after the attaching tool removing step. In this embodiment,
The left side of FIG. 1 is the front and the right side is the rear.

[Structure of Mold] First, as shown in FIG. 1, the mold 1 to which the set screw loosening prevention structure A according to the embodiment of the present invention is applied is such that molten metal is filled in the cavity 3 formed by the mold 1. The product is injection-molded by filling, and in order to form a hole portion that becomes a screw hole or the like in the product, the casting pin 2 is inserted into the mold 1 to project into the cavity 3, and the casting pin 2 A hole is formed in the product by casting. Note that the mold 1 is not limited in its material and structure such as a mold or a plaster mold. Further, a back block 5 is provided outside the mold 1, and a screw hole 4 penetrates through the back block 5 at a position corresponding to the casting pin 2. The inner diameter of the screw hole 4 is formed larger than the outer diameter of the cast pin 2, the spacer pin 40, which is a columnar member, is inserted into the screw hole 4, and the front end surface 4 of the spacer pin 40 is inserted.
1 is in contact with the cast pin 2. Further, the set screw 20 is screwed into the screw hole 4 from the rear side of the spacer pin 40 and pressed against the rear end surface 42 of the spacer pin 40, whereby the spacer pin 40 is fixed in the screw hole 4. As a result, the movement of the casting pin 2 in contact with the spacer pin 40 is restricted, and the spacer pin 40 is fixed to the mold 1. Therefore, it is necessary to securely fix the set screw 20 in the screw hole 4.

[Set Screw Loosening Prevention Structure] Next, as shown in FIG. 1, a set screw loosening prevention structure A according to an embodiment of the present invention is located behind a set screw 20 screwed into a screw hole 4. A spiral member 30 formed in a spiral shape so that a wire is screwed into the screw hole 4 is externally fitted to the portion 22, and the front end portion 3 of the spiral member 30.
1 engages the set screw 20.

Next, each component will be described. As shown in FIGS. 1 and 2A, the set screw 20 is a columnar member having an external thread formed on the outer peripheral surface thereof and capable of being screwed into the screw hole 4, and a front portion 21 having the external thread formed thereon. And spiral 3
0 is composed of a rear portion 22 having an outer peripheral shape that can be externally fitted. A mounting auxiliary hole portion 25, which is a hexagonal hole having a regular hexagonal cross section, is provided at the axial center of the front end surface 23 of the set screw 20.
(Auxiliary tool engaging portion) is formed, and a mounting hole portion 26 (mounting tool engaging portion), which is a hexagonal hole having a regular hexagonal cross section, is formed at the axial center of the rear end surface 24. Further, the rear end face 24 is provided with an engagement groove 27 into which the wire material forming the spiral body 30 can be engaged.
The (helical body engaging portion) is formed across the mounting hole portion 26 so as to pass through the axis.

As shown in FIGS. 1 and 2 (b), the spiral member 30 is formed by spirally forming an elastically deformable wire having a circular cross section into the screw hole 4. Is formed in a spiral shape of approximately 2.5 turns. A front end portion 31 and a rear end portion 32, which are bent and faced each other inside the spiral body 30 so as to be perpendicular to the axial direction of the spiral body 30, are formed at both ends of the wire forming the spiral body 30,
The rear end portion 32 is configured to be out of phase with the front end portion 31 in the tightening direction.

Here, the diameter reduction of the spiral body 30 will be described. When the rear end portion 32 of the spiral body 30 is rotated so as to be parallel to the front end portion 31, a torque in the slack direction is generated at the rear end portion 32, and the spirally formed wire rod is moved inward. Since the spiral body 30 is deformed to be narrowed, the entire diameter of the spiral body 30 is reduced. The outer diameter of the spiral body 30 is formed larger than the inner diameter of the screw hole 4, and can be screwed into the screw hole 4 by reducing the diameter. The reduced inner diameter of the spiral body 30 is of a size that can be externally fitted to the rear portion 22 of the set screw 20.

Further, as shown in FIG. 2C, the mounting tool 50 for mounting the set screw 20 and the spiral body 30 in the screw hole 4 has a mounting hole portion 26 of the rear end surface 24 of the set screw 20.
Is a hexagonal wrench that can be engaged with the front end portion 51 and the rear end portion 32 of the spiral body 30 with the front end portion 51.
2 is formed so as to pass through the axis.

[Set Screw Loosening Prevention Method] Next, a set screw loosening prevention method according to the embodiment of the present invention will be described. (1) Helical Body Engaging Step First, as shown in FIG. 3A, the front end portion 3 of the spiral body 30.
1 is engaged with the engagement groove 27 of the rear end surface 24 of the set screw 20. Since the engagement groove 27 is formed across the mounting hole portion 26, the front end portion 31 is engaged in a state of traversing the inside of the mounting hole portion 26.

(2) Helical Body Diameter Reduction Step Next, as shown in FIG. 3A, the auxiliary mounting tool 60, which is a hexagon wrench, is engaged with the auxiliary mounting hole portion 25 of the fixing screw 20, and the fixing screw 20 is also engaged. The engaging groove 52 of the mounting tool 50 is engaged with the rear end portion 32 of the spiral body 30 engaged with the mounting tool 50 and the rotation of the set screw 20 is locked by the mounting auxiliary tool 60. While twisting in the slack direction, it is pushed toward the set screw 20 to engage the tip 51 of the mounting tool 50 with the mounting hole 26. Then, the front end portion 31 of the spiral body 30 that traverses the inside of the mounting hole portion 26 is engaged with the engagement groove 52 of the mounting tool 50, and both ends 31, 32 of the spiral body 30 are made to face each other in parallel. As a result, as shown in FIG. 3B, the rear end portion 32 of the spiral body 30.
Torque in the slack direction is generated in the wire, and the wire formed in a spiral shape is deformed so as to be narrowed inward, so that the entire diameter of the spiral body 30 is reduced.

(3) Threading Step Next, as shown in FIG. 1, the spacer pin 4 is inserted into the screw hole 4.
After inserting 0 into contact with the front end surface 41 of the spacer pin 40 against the die-cast pin 3, as shown in FIG. 3 (c), the set screw 20 and the spiral body 30 are integrally rotated by the mounting tool 50. Screw into the screw hole 4. At this time, the spiral body 30
Since the diameter is reduced, the spiral body 30 can be easily screwed together with the set screw 20.

(4) Removal process of mounting tool Next, the front end face 23 of the set screw 20 screwed in is pressed against the rear end face 42 of the spacer pin 40 to fix the spacer pin 40 in the screw hole 4, and thus the spacer The casting pin 2 with which the pin 40 is in contact is fixed to the mold 1. Finally, the mounting tool 50 is attached to both ends 31, 3 of the set screw 20 and the spiral body 30.
Pull out from 2 and separate. As a result, the spiral body 30 is screwed into the screw hole 4 while being fitted onto the rear portion 22 of the set screw 20.

[Loosening prevention action] In the attaching tool detaching step, by detaching the attaching tool 50 from the spiral body 30, the parallel state of both end portions 31 and 32 of the spiral body 30 is released, and the elastic force of the spiral body 30 causes the entire spiral body 30 to be released. Expands.
As a result, the entire spiral body 30 is pressed against the inner peripheral surface of the screw hole 4, and the frictional force between the outer peripheral surface of the spiral body 30 and the inner peripheral surface of the screw hole 4 is increased. Rotation is prevented. That is, loosening of the set screw 20 with which the spiral body 30 is engaged is prevented.

Even if the set screw 20 is not prevented from being loosened by the loosening prevention action and the set screw 20 rotates in the loosening direction, as shown in FIG. 3D, the set screw 20 rotates. By this, torque in the slack direction is generated at the front end portion 31 of the spiral body 30, and the front end portion 31 rotates ahead of the rear end portion 32 in which no torque is generated in the slack direction, and the front end of the spirally formed wire rod is formed. Since the portion 31 is deformed so as to expand outward, the spiral body 30 tries to expand the diameter in the screw hole 4. As a result, the spiral body 30 is pressed against the inner peripheral surface of the screw hole 4 with a high pressure, and the outer peripheral surface of the spiral body 30 and the screw hole 4 are pressed.
Since the frictional force between the inner peripheral surface of the
Slack of 0 is surely prevented.

Therefore, in the loosening prevention structure A and the loosening prevention method for the set screw according to the embodiment of the present invention, the spiral member 3 is used.
0 is expanded and pressed against the inner peripheral surface of the screw hole 4, and the frictional force prevents the spiral body 30 from rotating, so that the set screw 20 engaged with the spiral body 30 is prevented from loosening. The set screw 20 is securely fixed in the screw hole 4.

An example of the preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment, and design changes can be appropriately made without departing from the spirit of the present invention. For example, as the spiral body 30, a wire rod having a rhombic cross-section may be formed in a spiral shape, and an existing helisert that uses a groove formed on the inner peripheral surface thereof as a female screw may be used.
In this configuration, since the groove formed on the outer peripheral surface of the helisert is screwed into the female screw of the screw hole 4 as a male screw, the frictional force between the outer peripheral surface of the helisert and the inner peripheral surface of the screw hole 4 is increased. The slack of the set screw 20 can be prevented more reliably. Further, the number of turns of the spiral body 30 is not limited, and it is preferable to appropriately set the number of turns in accordance with the sizes of the set screw 20 and the screw hole 4. Further, the front end portion 3 of the spiral body 30 can be fitted without externally fitting the spiral body 30 on the set screw 20.
1 may be engaged with the rear end surface 24 of the bolt 20 and the spiral body 30 may be provided behind the set screw 20. Also, the spiral body 30
The method for engaging the front end portion 31 of the above with the set screw 20 may be a joining method such as welding and is not limited. In addition, as a method of integrally rotating the set screw 20 and the spiral body 30 in the screwing step, for example, the tip portion 51 of the mounting tool 50 and the mounting hole portion 26 of the set screw 20 have a circular cross section, and the mounting tool 50 is stopped. The engaging tool 50 is engaged with the both ends 31, 32 of the spiral body 30 without engaging with the screw 20, and the torque of the attaching tool 50 is stopped.
The set screw 20 and the spiral body 30 may be integrally rotated by transmitting them to the set screw 20 via the front end portion 31 of the spiral body 30 engaged with the engagement groove 27. Further, in the spiral diameter reducing step, when the mounting tool 50 is pushed toward the set screw 20 while twisting in the loosening direction of the set screw 20, the rotation of the set screw 20 can be locked by the hand of the worker. For example, it is not necessary to engage the mounting auxiliary tool 60 with the set screw 20.

[0036]

According to the slack preventing structure and the slack preventing method of the present invention, when the set screw rotates in the screw hole, the slack direction is applied to one end of the spiral body screwed into the screw hole. When the torque is generated to try to expand the diameter, the spiral body is pressed against the inner peripheral surface of the screw hole, and the frictional force prevents the spiral body from rotating, preventing the set screw engaged with the spiral body from loosening. Thus, the set screw can be securely fixed in the screw hole. Further, in the configuration in which the outer diameter of the spiral body made of elastically deformable wire is formed larger than the inner diameter of the screw hole,
By reducing the diameter, the spiral body screwed into the screw hole is always in pressure contact with the inner peripheral surface of the screw hole, so that the rotation of the spiral body can be reliably prevented. Further, by generating a torque in the slack direction at the other end of the spiral body, it is possible to reduce the diameter of the entire spiral body and easily screw the spiral body into the screw hole. This is effective when the outer diameter of the spiral body is larger than the inner diameter of the screw hole. Further, in the configuration in which the spiral body is fitted onto a part of the bolt, the entire length in the axial direction of the set screw and the spiral body screwed into the screw hole can be shortened.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a loosening prevention structure for a set screw according to an embodiment of the present invention.

2A and 2B are diagrams showing respective constituent elements in the loosening prevention structure for a set screw according to the embodiment of the present invention, FIG. 2A is a perspective view showing a set screw, and FIG. 2B is a perspective view showing a spiral body;
(C) is a perspective view showing a mounting tool.

3A and 3B are views showing a method for preventing loosening of a set screw according to an embodiment of the present invention, in which FIG. 3A is a side view showing a spiral diameter reduction step, and FIG. 3B is a deformed state of the spiral element in the spiral diameter reduction step. FIG. 6C is a side view showing the screwing process, FIG.
FIG. 6 is a diagram showing a deformed state of the spiral body after the attaching tool detaching step.

FIG. 4 is a side sectional view showing a conventional bolt loosening prevention structure.

[Explanation of symbols]

A ... ・ Sag prevention structure 1 ... Mold 2 ... · Cast pin 3 ... Cavity 4 ... Screw hole 5 ... Back block 20 ... Set screw 21 ... Front part (set screw) 22 ··· Rear part (set screw) 23 ... Front end face (set screw) 24 ··· Rear end face (set screw) 25 ··· Mounting auxiliary hole (set screw) 26 ··· Mounting hole (set screw) 27 ··· Engagement groove (set screw) 30 ... Spiral 31 ... Front end (spiral) 32 ··· Rear end (spiral) 40 ... Spacer pin 41 ... Front end face (spacer pin) 42 ··· Rear end face (spacer pin) 50 ... Installation tool 51 ··· Tip (mounting tool) 52 ··· Engagement groove (installation tool) 60 ... ・ Auxiliary installation tool

Claims (5)

[Claims] 1. A set screw screwed into the screw hole is engaged with one end of a spiral body that is a spiral wire member screwed into the screw hole, and a torque in a slack direction is applied to the set screw. When generated, a torque in a slack direction is generated at one end of the spiral body, and the spiral body tries to expand its diameter, so that the rotation of the spiral body and the set screw is prevented. A structure that prevents loosening of the set screw. 2. A set screw loosening prevention structure using a set screw and a spiral body that is screwed together with the set screw into a screw hole to prevent the set screw from loosening, wherein the spiral body is a wire rod. Is formed in a spiral shape so as to be screwed into the screw hole, and both ends of the wire are bent and faced inside the spiral body so as to be perpendicular to the axial direction of the spiral body, The other end of the wire is configured to be out of phase with the one end of the wire in the tightening direction, and the set screw is engageable with one end of the spiral body. A spiral engagement portion is formed, and the spiral body and the set screw are screwed into the screw hole in a state where one end of the spiral body is engaged with the spiral body engagement portion. Screw loosening prevention structure. 3. The set screw according to claim 1, wherein the wire rod is elastically deformable, and an outer diameter of the spiral body is formed larger than an inner diameter of the screw hole. Slack prevention structure. 4. The screw according to claim 1, wherein the spiral body is screwed into the screw hole in a state of being externally fitted to a part of the set screw. Structure to prevent loosening of set screws. 5. A set screw, a spiral body that is screwed together with the set screw into a screw hole to prevent the set screw from loosening, a mounting tool and a mounting tool for mounting the set screw and the spiral body in the screw hole. A method for preventing loosening of a set screw using an auxiliary tool, wherein the spiral body is formed in a spiral shape so that an elastically deformable wire rod is screwed into the screw hole, and both ends of the wire rod are the spiral body. Is bent inwardly of the spiral body so as to be perpendicular to the axial direction of the wire rod, and the other end portion of the wire rod is out of phase with the one end portion of the wire rod in the tightening direction. The set screw is formed with a spiral body engaging portion capable of engaging the end portion of the spiral body at one end portion, and at the other end portion, an auxiliary member capable of engaging the mounting auxiliary tool. A tool engagement portion is formed, and the mounting tool is , A shaft portion having an outer diameter smaller than the inner diameter of the spiral body, and an engaging groove at the tip of the shaft portion, with which both ends of the wire of the spiral body can be engaged, passes through the shaft center of the shaft portion. And is characterized by including at least the following steps. (1) A first step in which one end of the wire rod of the spiral body is engaged with the spiral body engaging portion of the set screw. (2) The attachment auxiliary tool is engaged with the auxiliary tool engaging portion of the set screw, and the engagement groove of the attachment tool is engaged with the other end portion of the wire rod of the spiral body so as to assist the attachment. With the rotation of the set screw locked by a tool, the set tool is pushed toward the set screw while twisting the set tool in the loosening direction of the set screw, and the spiral body is inserted into the engagement groove of the set tool. A second step of engaging one end of the wire rod. (3) A third step in which the set screw and the spiral body are integrally rotated by the mounting tool and screwed into the screw hole. (4) A fourth step of pulling out and removing the mounting tool from the spiral body.