JP3105878B2 - bolt - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bolt, and more particularly, to a method of loosening a bolt that has been excessively tightened or removing a fixed bolt without using any special technique or tool, and using a bolt head. The present invention relates to a bolt that can be easily loosened without deforming a seat surface of a fastening member.

[0002]

2. Description of the Related Art Conventionally, a method of loosening a bolt that has been excessively tightened or removing a bolt that has been fixed has been hit by directly hitting the head of the bolt with a hammer or the like to give an impact to the bolt. . In this method, when the head of the bolt is hit with a hammer or the like, the head of the bolt or the seating surface of the workpiece may be deformed. Further, merely applying an impact to the bolt head does not sufficiently transmit the impact to a portion where the fastening member and the bolt are screwed, and the bolt may not be loosened.

When the bolt cannot be sufficiently loosened by hitting the head of the bolt, a method of shaving off the bolt using a drill having a size larger than the outer diameter of the bolt is used. However, in this method, the thread (female screw) provided on the workpiece is also broken. For this reason, when fastening the fastening member again using bolts or the like, it is necessary to newly cut a screw having a size larger than the broken screw.

[0004] As a method of not destroying the material to be fastened, a hole smaller than the bolt axis is provided by using a tool such as a drill in the axial direction of the bolt from the center of the head of the bolt. Then, there is known a method in which a reverse thread tapping process is performed to form a thread, and a reverse threaded bolt is screwed into the thread to take out a bolt shaft. However, this method is very time-consuming and requires special processing techniques and special processing tools.

As an example of a technique for extracting a bolt, there is known a method described in "Japanese Patent Laid-Open No. 57-144306: Method for extracting a reamer bolt". In the method described in this publication, as shown in FIG. 3, a cooling gas is blown into a hole 61 formed in the axial direction of the bolt 60 to cool the bolt 60 and shrink the bolt 60 so that the bolt 60 can be easily pulled out. . However, this method requires a preparation of a cooling gas and requires a special technique, so that it is not a method that can be easily adopted.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and uses a special technique or a special tool when loosening a bolt that has been excessively tightened or when a bolt that has been fixed is not removed. It is an object of the present invention to provide a bolt which can be easily loosened without deforming the head of the bolt or the seat surface of the material to be fastened.

[0007]

The object of the present invention is to provide a cylindrical shaft having a first thread provided on an outer peripheral surface thereof, and a cylindrical shaft provided at one end of the shaft. a body having a diameter composed of a large head, a second screw thread is provided on the outer peripheral surface, and a small cylindrical shaft member outer diameters than the shaft portion, wherein
The main body has an open end face on the head side and an end face on the shaft side.
Forming a mouth, penetrating through the shaft and the head,
A bearing hole positioned at the shaft center of the shaft portion is provided;
A third thread is formed on the inner wall of the third thread to be screwed with the second thread.
And the bearing hole forms the third thread.
To the opening formed in the shaft-side end face of the main body.
The inner diameter of the lower bearing hole is smaller than that of the lower bearing hole.
Thus, the opening formed in the end face on the head side of the main body is
The shaft member comprises an upper part of a bearing hole that extends.
2 threads are formed and can be screwed to the lower part of the bearing hole.
The lower part of the shaft member and the upper part of the bearing hole can be inserted freely.
And the shaft member is inserted into the bearing hole.
And the shaft member is screwed on the shaft member.
Part into the upper part of the bearing hole, and the lower part of the shaft member
Do not screw into the lower part of the bearing hole and insert it into the bearing hole.
It can be solved by a bolt, characterized in that that. Also,
In the above-mentioned bolt, the head is desirably hexagonal. Further, in the bolt, any one of a + groove, a-groove, and a hexagonal hole for receiving a tool for turning the main body may be formed on the end face on the head side. Further, in the above-mentioned bolt, it is preferable that at least one end face of the shaft member is formed with any of a + groove, a-groove, and a hexagonal hole for receiving a tool for turning the shaft member.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram for explaining an example of the bolt of the present invention, and FIG. 2 is a diagram illustrating the bolt shown in FIG.
FIG. In FIG. 1, reference numeral 1 denotes
A bolt is shown, reference numeral 4 indicates a first workpiece, and reference numeral 5 indicates a second workpiece.

The bolt 1 includes a main body 2 and a shaft member 3. The main body 2 has a cylindrical shaft portion 22 having a first thread (male screw) 22N provided on an outer peripheral surface thereof, and a head having an outer diameter larger than the shaft portion 22 provided on the shaft portion 22. And part 21. The shape of the head 21 as viewed from above in FIG. 1 is a hexagon as shown in FIG. As shown in FIGS. 1 and 2, the main body 2 is provided with a bearing hole 23 penetrating through the shaft portion 22 and the head portion 21 and located at the axis of the shaft portion 22. The bearing hole 23 has a third screw 2 on the inner wall.
Bearing hole lower part 23d in which 3N (female screw) is formed
When the bearing hole bottom 23d inside diameter smaller bearing on the hole than
It is made from a part 23c. An opening 23a of the bearing hole 23 is formed on the upper end surface 2a of the main body 2, and an opening 23b is formed on the lower end surface 2b.

Further, the shaft member 3 is provided on the outer peripheral surface with the third member.
The second shaft member lower 32 provided screw threads 32N (the male screw), the shaft member which is freely inserted into the bearing hole upper 23c by reducing the outer diameter than the shaft member lower 32 to the screw threads 23N and screwed
It consists of an upper part 31. The shaft member 3 is screwed into a bearing hole 23 of the main body 2. And the shaft member 3
By turning, the shaft member 3 can be moved to an arbitrary position in the length direction (vertical direction in the drawing).
As shown in FIG. 2, a hexagonal hole 3 for receiving a tool for turning the shaft member 3 is provided on an upper end surface 3a of the shaft member 3.
3 are formed.

The first fastening member 4 is provided with a hole having a fourth screw (female screw) 4N that is screwed with a first screw 22N provided on the shaft portion 22 of the main body 2. Have been. Also, the second fastening material 5 includes a shaft portion 2 of the bolt 1.
2, a hole 5a larger than the outer diameter of the head 21 is provided. The first fastening member 4 and the second fastening member 5 rotate the main body 2 of the bolt 1,
A first screw 22 provided on the shaft 22 of the main body 2
N is fastened by screwing a fourth thread (female screw) 4 </ b> N provided on the first workpiece 4.

To loosen such a bolt 1, first,
A hexagonal wrench or the like is inserted into a hexagonal hole 33 provided in the upper end surface 3a of the shaft member 3, and the shaft member 3 is turned by a method of rotating the hexagonal wrench, as shown in FIG. The shaft member 3 is moved upward as shown in FIG. 1 so that the upper end surface 3a of the shaft member 3 projects from the upper end surface 2a of the main body 2. And it is performed by the method of hitting the upper end surface 3a of the protruded shaft member 3 with a hammer or the like. At this time, the outer diameter of the shaft member lower part 32 is larger than the outer diameter of the shaft member upper part 31, and the bearing hole lower part 23d is located above the bearing hole.
Because the inner diameter is larger than the portion 23c, the shaft member
The portion 32 does not move to the position of the bearing hole upper portion 23c.

[0013] Such a bolt 1 comprises a main body 2 and a shaft member 3.
And the main body 2 is provided with a bearing hole 23,
Since the shaft member 3 is screwed into the bearing hole 23, the shaft member 3 is made to protrude by setting the position of the upper end surface 3a of the shaft member 3 to a position protruding from the upper end surface 2a of the main body 2. The bolt 1 can be loosened by hitting the upper end surface 3a of the shaft member 3 with a hammer or the like. That is, when an impact is applied to the upper end surface 3a of the shaft member 3 by a hammer or the like, the impact force is transmitted not only to the head 21 of the main body 2 but also to the entire shaft portion 22 via the shaft member 3, and The frictional force and the fixing force between the first screw 22N of the second member 22 and the fourth screw 4N of the first workpiece 4 are reduced, and the bolt 1 is loosened. Thus, bolt 1
Does not require special technology or special tools,
The head 21 of the bolt 1 and the seat surface of the second fastening member 5 can be easily loosened without being deformed.

Since the head 21 has a hexagonal shape, the bolt 1 can be easily turned with a general tool such as a spanner or an eyeglass wrench.

Further, the upper end surface 3a of the shaft member 3
A hexagonal hole 3 for receiving a tool for turning the shaft member 3
Since the shaft member 3 is formed, the shaft member 3 can be easily turned with a general tool such as a hexagon wrench, and the vertical position of the shaft member 3 can be easily moved.

Further, the lower shaft member 32 is connected to the upper shaft member 31.
Larger outer diameter than the bearing hole bottom 23d is on the bearing hole
Since the inner diameter is larger than the portion 23c, the shaft member lower part 32
Does not move to the position of the bearing hole upper part 23c,
Since the shaft member 3 does not come out of the bearing hole 23,
Loss of the shaft member 3 and entry of dust and the like into the bearing hole 23 can be prevented. Further, since no thread is provided in the upper shaft member 31 and the upper bearing hole 23c, the upper shaft member 31 and the upper bearing hole 23c
Also, the time required for tapping can be reduced as compared with the case where a thread is formed.

The head 21 may be formed with a + groove, a-groove, a hexagonal hole, or the like for receiving a tool for turning the main body 2. By using such a bolt 1, it becomes possible to turn the main body 2 using a tool such as a hexagon wrench, a Phillips screwdriver, or a flathead screwdriver, and use a tool such as a spanner or an eyeglass wrench around the head 21. It can be used as a bolt 1 that is preferably used in places where no space is available for mounting. Furthermore, the head 2
The shape of 1 may be hexagonal as in the above-described example, but may be polygonal such as quadrilateral, hexagonal, octagonal, or circular, and is not particularly limited.

In the above bolt, the shaft member 3
A hexagonal hole 33 for receiving a tool for turning the shaft member 3 is formed in the upper end face 3a of the
-It can also be a groove. Furthermore, the lower end surface 3b of the shaft member 3 may be formed with a hexagonal hole 33, a + groove, and a-groove for receiving a tool for turning the shaft member 3. With such a bolt 1, when the shaft member 3 is screwed into the main body 2 to form the bolt 1, the shaft member 3 is turned using a tool such as a hexagon wrench, a Phillips screwdriver, or a flathead screwdriver. And the shaft member 3 can be easily
Can be turned.

[0019]

[0020]

[0021]

As described above, the bolt of the present invention comprises a main body including a head and a shaft, an upper portion of the shaft member, and a lower portion of the shaft member.
A shaft member comprising:
A bearing hole comprising a portion and a lower portion of the bearing hole is provided, and a shaft member is provided.
The upper part is inserted into the upper part of the bearing hole, and the lower part of the shaft member is the bearing hole
Screwed into the lower part, the shaft member is screwed into the bearing hole
Therefore, the position of the upper end surface of the upper part of the shaft member is set to a position protruding from the end surface on the head side of the main body, and the bolt can be loosened by hitting the protruded upper end surface of the upper part of the shaft member with a hammer or the like. . That is, when an impact is applied to the upper end surface of the upper portion of the shaft member by a hammer or the like, the impact force is transmitted not only to the head portion of the main body but also to the entire shaft portion via the shaft member, and the first screw of the shaft portion Reducing the frictional force and the fixing force between the thread and the fourth thread of the first fastening member,
Bolts are loosened. Therefore, the bolt can be easily loosened without using a special technique or a special tool, and without deforming the head of the bolt or the bearing surface of the second workpiece.

[Brief description of the drawings]

FIG. 1 is a view for explaining an example of a bolt of the present invention.

FIG. 2 is a view of the bolt shown in FIG. 1 as viewed from above in FIG.

FIG. 3 is a sectional view showing an example of a conventional bolt.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Bolt 2 Main body 2a Upper end face 2b Lower end face 21 Head 22 Shaft part 22N First screw 23 Bearing hole 23a Opening 23b Opening 23c Bearing hole upper part 23d Bearing hole lower part 23N Third screw 3 Shaft member 3a Upper end face 3b Lower end surface 31 Upper shaft member 32 Lower shaft member 32N Second screw 33 Hexagon hole 4N Fourth screw 4 First fastening member 5 Second fastening member 5a Hole

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-159314 (JP, A) JP-A-8-277825 (JP, A) JP-A 7-29306 (JP, U) JP-A 4-29325 88512 (JP, U) JP 3-7515 (JP, U) JP 6-20890 (JP, Y2) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16B 35/00 B25B 27 / 18

Claims (4)

(57) [Claims] 1. A cylindrical shaft having a first thread provided on an outer peripheral surface thereof, and a head provided at one end of the shaft and having a larger outer diameter than the shaft. A main body, a second thread is provided on an outer peripheral surface, and a cylindrical shaft member having an outer diameter smaller than the shaft portion. The main body includes an end surface on the head side and the shaft portion side. With the end face of
Forming an opening in the shaft portion and the head portion,
A bearing hole positioned at the axis of the shaft portion;
A third screw threadedly engaged with the second screw thread is formed on the inner wall of the drill hole.
And the bearing hole forms the third thread, and
Under the bearing hole leading to the opening formed in the end face on the shaft side of the
Part and an inner diameter smaller than the lower part of the bearing hole,
Bearing hole leading to the opening formed in the end face on the head side of the body
The shaft member is formed with the second thread and the bearing
A shaft member lower portion which can be screwed to a hole lower portion, and the bearing hole;
An upper shaft member that can be inserted into the upper portion, the shaft member is screwed into the bearing hole, and the shaft member inserts the upper shaft member into the upper bearing hole.
Through, screw the lower shaft member into the lower bearing hole,
The bolt is inserted into the bearing hole.
G. 2. The bolt according to claim 1, wherein the head is hexagonal. 3. The head-side end face is formed with one of a + groove, a -groove, and a hexagonal hole for receiving a tool for turning the main body. 2
Bolt described. 4. A groove for receiving a tool for rotating the shaft member, at least on an end surface on the head side of the shaft member.
The bolt according to any one of claims 1 to 3, wherein any one of a groove and a hexagonal hole is formed.