WO2012070272A1

WO2012070272A1 - Bolt

Info

Publication number: WO2012070272A1
Application number: PCT/JP2011/064812
Authority: WO
Inventors: 長谷川　賢司
Original assignee: 株式会社ハマ・システム
Priority date: 2010-11-25
Filing date: 2011-06-28
Publication date: 2012-05-31
Also published as: JP2012127494A; JP5413995B2

Abstract

Provided is a loosening prevention bolt having a simple and novel configuration and capable of reliably preventing loosening and of being repeatedly used in a wide range of construction processes. This bolt comprises: a bolt body; a diameter expanding member; and a fastening shaft portion. The bolt body includes a shaft hole in a shaft core portion, and also includes a space in the shape of a circular truncated cone. A plurality of slits for expanding the diameter is formed in the circumferential direction of a cylindrical portion in which the space is formed. The diameter expanding member is disposed in the space. The axial rotation of the diameter expanding member is prevented by a rotation prevention means. The diameter expanding member comes into contact with the inner wall of the cylindrical portion and includes a communication hole. The fastening shaft portion is inserted into the shaft hole of the bolt body and the communication hole of the diameter expanding member. A thread portion is formed on at least part of the outer periphery of the fastening shaft portion. With this configuration, the fastening shaft portion moves the diameter expanding member inside the space at the time of axial rotation and imparts the diameter expanding force to the bolt body.

Description

bolt

The present invention relates to a bolt having a locking function.

Between the female thread part engaged with the thread part of the bolt, the spiral thread / groove surface is generated based on the reaction in the longitudinal direction acting between the spiral thread / groove provided around the longitudinal axis. The mutual rotation is stopped by the component force of the friction force between them, and the fixed relationship is maintained. However, since the frictional force generated between the spiral strip and the groove surface is only generated between the smooth sloped surfaces, the tightening member expands and contracts due to temperature changes, and the vibration is repeated for a long time. The above-mentioned fixing condition between the bolt and nut may be broken based on slippage between the inclined surfaces, and the bolt may loosen or fall off, causing an accident.

Therefore, in order to prevent this type of accident, various methods for preventing loosening of bolts and nuts have been proposed.

Patent Document 1 also discloses a locking bolt. As shown in FIG. 11A, the locking bolt of Patent Document 1 includes a headed bolt 201 having a frustoconical convex portion 202 concentric with the bolt shaft core on the lower surface of the tip, It comprises a disc-shaped receiving member 204 having a convex portion 202 and a symmetrical concave portion on the upper surface. The disc-shaped receiving member 204 is inserted into a bottomed screw hole in advance, and a frustoconical convex portion provided at the tip of the bolt. By engaging the portion 202 eccentrically with the disc-shaped receiving member 204, a large shearing stress in a direction orthogonal to the axial direction is applied to the bolt, so that the bolt is securely locked.
In FIG. 11B, an outer screw having the same pitch as that of the bolt 201 is formed on the outer peripheral surface of the disc-shaped receiving member 204 ′, and a box wrench is formed on the upper surface of the convex portion of the disc-shaped receiving member 204 ′. An engaging portion with which a rotating tool (not shown) such as the like is engaged is provided, and the disc-shaped receiving member 204 ′ is screwed to a predetermined position of the bottomed screw hole 205 with a predetermined rotating tool. ing.

Japanese Patent Laid-Open No. 10-37936

The bolts of this type that have been known so far have a complicated anti-loosening member and structure, which may increase costs, require too much work, or have a narrow scope of anti-loosening construction (existing). There is a difficulty such as only corresponding to the bottom screw hole or conversely only to the through screw hole.
In addition, in the disclosed technique of Patent Document 1, since the prevention of looseness is uniformly determined by the amount of eccentricity between the concave portion of the disk-shaped receiving member and the convex portion of the bolt tip, depending on the hardness or tolerance of the fastened object, it is possible to give a loosening prevention force. Excessive or insufficient may not be able to prevent the slack reliably.
Accordingly, an object of the present invention is to provide a slack prevention bolt having a new structure that can reliably prevent slack with a simple structure, has a wide construction range, and can be used repeatedly.

In order to solve the problem, the bolt of the present invention has a frustum-like space that has a shaft hole in the shaft core portion and is widened so that at least one end portion in the shaft core direction of the shaft hole is closer to the end. A bolt body in which a plurality of slits for expanding the diameter are formed at positions in the circumferential direction with respect to the cylindrical portion in which the space is formed, and the bolt body disposed in the space by the rotation preventing means The shaft is prevented from rotating with respect to the frustoconical side surface contacting the inner wall of the space and a diameter-expanding member having a connection hole, and inserted into the shaft hole of the bolt body and the connection hole of the diameter-expansion member. At least a portion of the shaft hole is provided with a threaded portion that engages with a threaded portion on the inner surface side of the shaft hole, so that the diameter-expanding member is moved in the space when the shaft is rotated, and a diameter expansion force is applied to the bolt body. And a fastening shaft portion.

The bolt according to the present invention has a horizontal component force inside the bolt after final tightening and exhibits a rotation-inhibiting effect and can surely prevent the bolt from loosening.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the volt | bolt of 1st Embodiment of this invention, (a) is a top view, (b) is a partial cross section side view, (c) is a bottom view, (d) is a top view of a subbolt alone, e) is a side view of the diameter-expanding member. The subbolt in 1st Embodiment is shown, (a) is a top view, (b) is a front view, (c) is a bottom view. (A)-(d) is explanatory drawing which shows the example of the diameter expansion member which concerns on this invention. (A), (b) is a figure which shows the use condition which attached the volt | bolt to the to-be-fastened object, (a) is the state screwed to the bottomed screw hole, (b) was screwed to the penetration screw hole. Indicates the state. The bolt of 2nd Embodiment of this invention is shown, (a) is a fragmentary sectional view of the axial direction of a volt | bolt, (b) is a front view of a subbolt independent, (c) is a nut as a latching body. FIG. It is a figure which shows the other use condition in 1st, 2nd embodiment, (a) shows the state screwed in the bottomed screw hole, (b) shows the state screwed by the penetration screw hole. It is a figure which shows the structure of the volt | bolt of 3rd Embodiment in a use condition. It is a figure which shows the structure of the volt | bolt of 4th Embodiment in a use condition. It is a figure which shows the structure of the volt | bolt of 5th Embodiment in use condition. It is a figure which shows the structure of the volt | bolt of 6th Embodiment in use condition. (A), (b) is a figure explaining a known locking bolt.

[First Embodiment]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a bolt 10 according to a first embodiment of the present invention, where (a) is a top view, (b) is a partially sectional side view, (c) is a bottom view, and (d) is a sub-bolt alone. A top view and (e) are side views of the diameter-expanding member.
The bolt 10 includes a bolt main body (first bolt) 11, a sub bolt (second bolt) 21, and a diameter-expanding member (so-called top) 31.
2A and 2B show the bolt main body 11, where FIG. 2A is a top view, FIG. 2B is a side view, and FIG. 2C is a bottom view.

The bolt body 11 will be described with reference to FIGS. 1 and 2. A bolt body 11 shown in FIGS. 1 and 2 is a hexagonal head type head fastening bolt in which a cylindrical shaft portion 11a protrudes from a hexagonal body head 12 and is integrally formed. A side surface of the main body head 12 serves as a tool engaging portion 12a. In addition, a concave portion 11f is formed in the center of the main body head 12 of the bolt main body 11 to accommodate a locking head 21a of the sub bolt 21 described later (see FIG. 1B).
The bolt main body 11 has a shaft hole 11b in the shaft core portion, and at least the tip portion of the outer peripheral surface of the shaft portion 11a is formed with a spiral groove (male screw) 11c to form a screw portion. A space 11d having a frustoconical shape (hereinafter referred to as a truncated cone shape) is formed in the shaft core portion (inside the bolt) at the tip end portion of the threaded portion so as to increase greatly toward the bolt tip side. Moreover, it extends to the middle of the threaded portion from the distal end toward the main body head portion 12 at the distal end portion of the shaft portion 11a formed with a space 11d, and has a distal end surface (annular surface) in the circumferential direction. A radial slit 11e that is divided into four (for example, equally divided) is formed.

In the space 11d, a diameter-expanding member 31 having a truncated cone-shaped side surface (conical truncated cone portion) 31a that contacts the inner wall of the space is disposed (see FIG. 1).

The diameter-expanding member 31 will be described with reference to a top view, a front view, and a bottom view shown in FIG.
The frustoconical diameter expanding member 31 has an outer shape of a truncated cone in which the apex of a cone having an apex angle of 8 degrees (the angle is exaggerated in the drawing) is eliminated, for example. Here, the apex angle means a fan-shaped inner angle obtained by developing the side surface of the cone. A connecting hole 31 b is screwed in the shaft core portion of the diameter-expanding member 31 as a screw hole that is screwed with the tip screw portion 21 c (see FIG. 1D) of the sub bolt 21.
Further, the side peripheral surface (conical truncated side surface) 31a functions as a rotation preventing means for extending in the axial direction (length direction) and preventing circumferential rotation corresponding to the slit 11e of the bolt body 11. A plate-like blade member 31c is formed to serve as a protrusion (locking protrusion). In this embodiment, the blade member 31c is formed separately and is fitted and fixed to a slit extending in the axial direction that is formed in the radially expanding member main body at four equal positions in the circumferential direction. Of course.
In the embodiment, the four blade members 31c are provided corresponding to all the slits 11e. However, the blade members 31c may be provided only at two axially symmetric positions according to the application of the slack prevention bolt. The diameter-expanding member 31 expands the tip threaded portion of the bolt body 11 outward by moving upward in the space 11d.
The ratio of the diameter expansion to the movement amount of the diameter expansion member 31 at this time is determined by the shape of the diameter expansion member 31, particularly the apex angle of the truncated cone side surface 31a. As shown in FIG. 3D, when the length (axial dimension) of the diameter-expanding member 31 is increased, the ratio of the diameter expansion with respect to the unit movement amount can be reduced, adjustment is easy, and a finer diameter expansion (slack prevention force). Is possible). Further, when it is desired to increase the diameter expansion range, it is preferable to increase the length of the diameter expansion member 31 in this way.

As the above-mentioned diameter-expanding member, at least a part has a truncated cone portion, and the truncated cone-shaped side surface 31a of this truncated cone-shaped portion comes into contact exclusively with the side surface of the space 11d for diameter expansion. In addition, if an upward stress is applied to the diameter-expanding member 31, it is sufficient if the tip end portion of the spiral groove 11c of the bolt main body can be pressed to the radially outer peripheral side.

As shown in FIG. 3 (b), instead of the protrusion as the rotation preventing means, a pin is provided at a position corresponding to the slit as a locking means that engages with the slit 11e and prevents the rotation on the side surface of the diameter expanding member 31. (Locking protrusion) 31c may be erected.
Further, in place of such a locking projection, in order to prevent rotation of the diameter-expanding member 31 inserted into the space 11d, a knurl extending in the axial direction on the truncated cone-shaped side surface 31a as shown in FIG. Processing may be performed. An anti-rotation effect can be obtained by a simple method. In this case, the unevenness due to the knurling process is the rotation preventing means.

A secondary bolt (second bolt) 21 shown in FIG. 1 (d) has a fastening shaft portion 21b slidably inserted into and removed from a shaft hole 11b formed in the shaft portion 11a, and an upper end of the fastening shaft portion 21b. It is comprised by the locking head (top rotation drive body) 21a formed integrally. The length of the fastening shaft portion 21b of the sub bolt 21 is substantially the same as or slightly shorter than the length of the shaft hole 11b of the bolt body 11.

The auxiliary bolt 21 has a locking head portion 21a in a flat cylindrical shape with a large diameter, and a fastening shaft portion 21b extends from the center of the flat surface. A spiral groove (male thread) 21c of a screw part is engraved at the tip of the fastening shaft part 21b. The fastening shaft portion 21b is inserted into the shaft hole 11b provided in the bolt main body 11, and is screwed to the diameter-expanding member 31 by the screw portion 21c at the tip.
In this example, the locking head 21a functions as a locking body that makes contact with the upper surface on the head side of the bolt body 11 (here, the bottom surface of the recess 11f for storing the head) as a seating surface. A tension for pulling up the diameter-expanding member 31 screwed at the tip of the portion 21b through the fastening shaft portion 21b is generated. That is, in this example, the fastening shaft portion 21b functions as a connecting shaft having a screw portion screwed to the tip portion. In addition, a hexagonal engagement recess is formed in the center of the upper surface of the locking head 21a of the sub bolt 21 as a tool engagement portion 21d that engages with an appropriate rotary tool.

A frustoconical diameter-expanding member 31 corresponding to the space 11d is coaxially attached to the lower end of the above-described sub bolt 21 (the tip opposite to the locking head 21a side). The distal end portion of the shaft portion 11a can be expanded from the inner side to the outer peripheral side to increase the diameter (giving a diameter expansion force).

In the present invention, the shaft portion 11a, the auxiliary bolt 21, and the diameter-expanding member 31 can be made of a metal such as iron or stainless steel. In addition, it can be made of hard plastic with sufficient rigidity. In addition, although the direction of the screw of the spiral groove 21c of the sub bolt 21 is the same general right screw as that of the bolt body 11, it may be a reverse screw at all.

In the assembly of the bolt 10 of the embodiment, the auxiliary bolt 21 is passed through the shaft hole 11b of the bolt main body 11, the diameter-expanding member 31 is screwed into the distal end portion of the fastening shaft portion 21b, and is lightly screwed to be temporarily fixed ( (Refer FIG.1 (b)). In this state, the tip threaded portion of the bolt body 11 does not bulge radially outward (does not expand), maintains the normal dimensions, and can be handled in the same way as a normal bolt.

In order to couple two objects to be fastened A and B with the bolt 10 of this embodiment, as shown in FIG. 4A, a base having a spiral groove cut into a spiral groove 11c of the bolt body 11 is cut. The bolt main body 11 is screwed into the spiral groove of the article B to be fastened (the right side in the figure). Although not shown, in principle, a spring washer is used. When screwing, the bolts are tightened with a wrench or the like, the lower part of the bolt head is brought into contact with the surface of the object A to be fastened, and the objects A and B are fastened with a normal tightening strength.

Then, to further prevent loosening, the auxiliary bolt 21 is rotated by inserting and turning, for example, a hexagonal wrench (not shown) into a hexagonal hole (FIG. 1A) provided in the head of the auxiliary bolt 21 to rotate the auxiliary bolt 21. The bolt 21 is engaged with a diameter-expanding member 31 that is screwed to the tip of the bolt 21 and is tightened so that a stress that draws the diameter-expanding member 31 toward the locking head 21a is always applied. As a result, stress in the direction perpendicular to the axial direction is applied to the inner wall of the space that contacts the frustoconical side surface 31a of the diameter-expanding member 31 to expand the diameter of the tip threaded portion of the bolt body 11 (expand the width). The lock effect is demonstrated. As a result, loosening of the bolt can be reliably prevented. Thereafter, even if strong vibration is applied, the connection of the bolt main body 11 is loosened and does not rotate in the direction of disengagement.

If the worker wants to loosen, first loosen the secondary bolt 21. As a result, the holding force of the bolt main body 11 is reduced. In this state, a general-purpose tool (driver, wrench, etc.) that enables the bolt main body to rotate is engaged, and the direction in which the bolt main body 11 is removed (attachment direction) The bolt 10 can be removed from the object to be fastened. If necessary, the removed bolt 10 can be used again.

The use example shown in FIG. 4B is an example in which the hole provided with the spiral groove of the article to be fastened B is a through hole. In this case as well, the bolt main body 11 is the same as described above. When the

bolts

21 and 21 are tightened in order, the tip of the bolt body 11 expands in diameter and is in an open state, so that a slack prevention effect can be obtained. The bolt will not float. In the case of an application intended for the through screw hole of FIG. 4B, a more appropriate loosening prevention effect can be obtained by using the diameter-expanding member 31 having the shape shown in FIG. In the diameter-expanding member 31 of FIG. 3 (d), for example, a truncated cone having, for example, a truncated cone having an apex angle of 30 degrees, which is continuously connected to the lower base of the truncated cone having an apex angle of 8 degrees eliminated. A blade member 31c is fixed to a frustoconical main body portion (the angle is exaggerated in the drawing) on the side peripheral surface having a constriction formed with an upper bottom. The diameter-expanding member 31 is passed through the shaft hole 11b of the bolt body 11, and the diameter-expanding member 31 is screwed into the tip portion of the shaft portion 21a and lightly screwed and temporarily fixed (assembled).

In addition, the slack prevention bolt 10 of this embodiment has the advantage of reducing the cost because it can be firmly screwed without using a nut even for a portion where it is difficult to attach the nut from the back side. In addition, it can be reused and is economical.

In the above-described embodiment, the tool engaging portion 21d of the sub bolt 21 has a hexagonal recess, but a polygonal hole that fits a polygonal wrench, a minus or a Phillips screwdriver is inserted as the tool engaging portion. It may be a negative or positive groove or the like. Needless to say, the locking head 21a of the sub bolt 21 may be configured such that its outer periphery is formed in a hexagonal shape and can be rotated by a box spanner or the like. In any case, the tool engaging portion may have any shape as long as the auxiliary bolt 21 can be rotated. Also, the bolt main body 11 may have a shape other than the hexagonal shape as the tool engaging portion 12a for rotating the bolt main body 11.

[Second Embodiment]
A bolt 10A capable of preventing slack according to the second embodiment will be described with reference to FIG. 5A and 5B show a bolt 10A of the second embodiment, in which FIG. 5A is a partially sectional side view, FIG. 5B is a side view of a fastening shaft portion 31e alone to which a diameter-expanding member 31A is attached, and FIG. FIG.
In the second embodiment, the spiral groove is not formed on the side of the diameter-expanding member 31A, but a fastening shaft in which a spiral groove (male thread) is screwed at the tip on the side opposite to the side on which the diameter-expanding member 31A is attached. This is part 31e. The diameter-expanding member 31A and the fastening shaft portion 31e may be formed integrally or separately.
More specifically, in this embodiment, the connecting shaft combined with the bolt body 11 described above is integrated from the upper bottom surface side of the truncated cone portion of the diameter-expanding member (FIG. 3C) already described in the first embodiment. The fastening shaft portion 31e is formed. The fastening shaft portion 31e functions as a connecting shaft that can be inserted into the shaft hole 11b of the bolt main body 11, and has a spiral groove 31g (male screw) of a screw portion screwed to the tip portion (upper end). The diameter-expanding member 31A is fixed to the other end portion (lower end portion) where the screw portion of the fastening shaft portion 31e is not formed. The diameter-expanding member 31A has a knurled groove in the length direction (axial direction) on the side surface (the truncated cone-shaped side surface 31a) of the truncated cone portion 31f in order to prevent rotation. The bolt body 11 is exactly the same as in the first embodiment.

The fastening shaft portion 31e to which the diameter expanding member 31A is fixed is inserted into the shaft hole 11b from the side opposite to the head of the bolt body 11, and the truncated cone portion 31f is applied to the inner wall of the truncated cone space 11d. Push in.
A nut 41 corresponding to the spiral groove 31g is accommodated in the concave portion 11f of the main body head of the bolt main body 11. The inner hole of the nut 41 communicates with the shaft hole 11b of the bolt body 11 and constitutes a part of the “bolt body shaft hole” in the present invention.

The spiral groove 31g of the fastening shaft portion 31e is screwed with the inward spiral groove of the nut 41, and lightly screwed and temporarily fixed (assembled).
In use, the bolt body 11 is screwed to the object to be fastened in the same manner as in the first embodiment, and then the nut 41A is tightened from the head side of the bolt body 11 so that the diameter-expanding member 31A is within the space 11d at the tip of the bolt body. It is configured to add a pulling tension. The bolt 10A for preventing slack according to the second embodiment can be used similarly to the case of the first embodiment described above to obtain the same action and effect, and can surely prevent slack.

In the example of use in FIG. 4, the bolt head protrudes from the surface of the object A to be fastened. When it is desired to avoid the protrusion of the bolt head, as shown in FIG. 6, a recess Aa in which the head fits on the surface of the article A to be fastened may be formed in advance. The bolt that can be used in this example may be either the bolt 10 of the first embodiment or the bolt 10A of the second embodiment. FIG. 6 differs from FIG. 4 in that a concave portion Aa in which the head fits is provided on the surface of the article A to be fastened, but the bolt itself is as described above.

[Third Embodiment]
FIG. 7 is a partial cross-sectional view of the bolt 10B according to the third embodiment of the present invention in use.
The bolt 10 B includes a bolt body 11 B, a sub bolt 21, and a diameter-expanding member 31 (or 31 A). Among these, the bolt main body 11B is different from the bolt main body 11 of the first and second embodiments, and its head is a dish-shaped head 12B. Other configurations are the same as those of the bolt 10 (or 10A) used in the usage example of FIG. In addition, as a matter of course, the head may be the head 12B even in the use example with the bottomed shaft hole as shown in FIG.
In addition, when the head is a dish shape, it is generally not possible to use the side surface as a tool engaging portion. Therefore, it is preferable to form a groove or the like having a “+” or “−” top view as a tool engaging portion on the upper surface of the head. Or the recessed part in which the head of the subbolt 21 is accommodated can be made into polygonal shapes, such as a hexagon, for example, and this can be used as a tool engaging part.

[Fourth Embodiment]
FIG. 8 is a partial cross-sectional view of the bolt 10C according to the fourth embodiment of the present invention in use.
This embodiment is suitable when the hole provided with the spiral groove of the article B to be fastened is a through hole.
The bolt 10 C includes a bolt body 11 C, a sub bolt 21, and a diameter-expanding member 31 (or 31 A). Among these, the bolt main body 11C is different from the bolt main body 11 of the first and second embodiments, and the shaft hole 11b is a bottomed screw hole that opens at the front end surface of the shaft portion 11a and extends toward the main body head 12 side. It has become.

At the time of attachment, first, the bolt body 11 is inserted into the through holes of the objects A and B to be fastened from the surface side of the object A to be fastened. In this example, a thread portion is formed on the inner peripheral wall of the through hole of the fastened object B. Therefore, the main body head 12 is rotated with a hand or a tool, the bolt main body 11 is inserted, and temporary fixing is performed.
The auxiliary bolt 21 is inserted not from the inside of the main body head 12 (the surface side of the object A to be fastened) but from the surface side of the object B to be fastened as in the first to third embodiments. At this time, after the diameter-expanding member 31 (or 31A) is inserted into the truncated cone-shaped space 11d formed at the tip of the shaft portion 11a, the connecting hole (through hole) of the diameter-expanding member 31 (or 31A) ), The connecting shaft portion of the sub bolt 21 is inserted into the shaft hole 11 b of the bolt body 11. Then, the spiral groove provided at least at the tip end of the connecting shaft portion is screwed with the spiral groove on the inner peripheral wall of the shaft hole 11b, and the locking head portion 21a of the sub bolt 21 is rotated with a jig or the like to be strong or moderate. Tighten to. At this time, as described above, the diameter-expanding member 31 moves in the space 11d, and the movement is mainly performed by being pushed by the locking head 21a of the sub bolt 21. That is, the sub bolt 21 gives a pressing force to the diameter-expanding member 31 instead of the tension that draws toward the locking head. Thereby, like other embodiment, the front-end | tip part (cylindrical part in which the space 11d was formed) of the volt | bolt main body 11 expands outside, and slack prevention is given.

In addition, you may form previously the recessed part which accommodates the main body head 12 of the bolt main body 11 in the surface of the to-be-fastened object A similarly to FIG. Further, the main body head 12 may have a dish shape similar to that shown in FIG. The diameter-expanding member 31 only needs to be prevented from rotating. In addition to having a slit, the diameter-expanding member 31 may have a truncated cone shape having a through-hole by performing a knurling process on the outer peripheral wall as shown in FIG. Note that the bolt 10 C of the present embodiment cannot be used when the object to be fastened B is a wall or the like as shown in FIG.

[Fifth Embodiment]
FIG. 9 is a partial cross-sectional view of the bolt 10D according to the fifth embodiment of the present invention in use.
The bolt 10D of the present embodiment is worn and strong even if the through holes of the fastened objects A and B are larger than the outer diameter of the bolt body, or the inner peripheral wall of the through hole cannot be threaded. Even if tightening is not possible, it is possible to prevent loosening.

The bolt 10 D is the same as the first embodiment (FIG. 1) in that it has a bolt body 11 that can accommodate the auxiliary bolt 21 and a diameter-expanding member 31. In the first embodiment (FIG. 1), the diameter-expanding member 31 is disposed in advance in the tip portion of the bolt body 11.
When the bolt 10 of the first embodiment is applied to the fastened objects A and B having through holes larger than the outer diameter of the bolt body 11 as shown in FIG. Sufficient clamping force may not be obtained.

Therefore, in the fifth embodiment, the diameter-expanding member 31, the nut 13, and the washer 14 inserted from the outside of the article B to be fastened are used.
The nut 13 is not a normal nut, but has a truncated cone-shaped through hole whose width is increased as the distance from the surface of the fastened object B increases, thereby forming a part of the truncated cone-shaped space. .

In mounting, first, the bolt body 11 in which the sub bolt 21 is inserted until the locking head 21 a of the sub bolt 21 is received in the recess of the main body head 12 is inserted into the through holes of the fastened objects A and B. To do. In this state, the washer 14 and then the nut 13 are temporarily fixed from the surface of the fastened object B to the projecting tip of the bolt body 11. Then, the diameter-expanding member 31 is inserted from the outside of the nut 13 so that each of the blade members engages with a slit (not shown) formed at the tip of the bolt body 11. In this state, while holding the nut 13 with a tool or the like so as not to rotate, the locking head 21a of the sub bolt 21 is rotated with another tool such as a hexagon wrench. Then, the tension that draws the diameter-expanding member 31 toward the locking head side of the sub bolt 21 acts, and the diameter-expanding member 31 moves inwardly in the truncated cone space. For this reason, the force which presses against the surface of the to-be-fastened object B acts also on the nut 13, and the force which expands the front-end | tip part of the bolt main body 11 is provided simultaneously. As a result, the fastened objects A and B are tightened and the bolts themselves are firmly fixed so as not to loosen.

[Sixth Embodiment]
FIG. 10 is a partial cross-sectional view of the bolt 10E according to the sixth embodiment in use.
The bolt 10E is greatly different from the other first to fifth embodiments in the configuration of the bolt body 51. Although the bolt body of the first to fifth embodiments has a single shaft hole 11b, the bolt body 51 of this embodiment has two shaft holes 51b formed at both ends in the axial direction. Each of the two shaft holes 51b is greatly opened at the end face of the bolt main body, and the diameter gradually decreases in the axial direction from the opening to form a truncated cone-shaped space 51d. A bottomed hole which is smaller in diameter and forms a part of the shaft hole 51b is formed on the circular bottom surface of the reduced diameter of the space 51d, and a spiral groove is formed on the inner peripheral wall of the bottomed hole. Yes.

As shown in FIG. 10, the bolt body 51 having such a configuration is passed through the through holes of the objects A and B to be fastened, and both end portions (spiral grooves are formed from the surfaces of the objects A and B to be fastened). The protruding part is almost the same.
At each protruding end portion of the bolt body 51, a ring member 13E having a spiral groove on the inner peripheral surface that engages with the spiral groove on the outer peripheral surface is mounted together with the washer 14.
In this state, the diameter-expanding member 31 (for example, the same shape as FIG. 3D) is inserted into the frustoconical space 51d at both ends of the bolt body 51 from the outside. Further, the auxiliary bolt 21 is inserted through the connecting hole of the diameter expanding member 31 and rotated with a tool or the like. The sub-bolt 21 is smaller than that shown in FIG. 1 (d), but includes a locking head 21a and a fastening shaft portion 21b, and is the first in that a spiral groove is formed at least at the tip of the fastening shaft portion 21b. Similar to that used in one embodiment.

When the auxiliary bolt 21 is rotated and screwed into the shaft hole 51b, the diameter-expanding member 31 is prevented from rotating by the rotation preventing means such as the blade member 31c engaged with the slit of the bolt main body 51 as in the first embodiment. Is done. Further, the diameter-expanding member 31 is pushed inward by the locking head 21a of the sub bolt 21 and moves inward in the truncated cone-shaped space 51d. Therefore, the end of the bolt main body 51 is expanded in diameter and strongly pressed against the inner peripheral wall of the ring member 13E, and a force that presses the ring member 13E against the fastened object A or B side acts.
By performing the operation of tightening the sub bolt 21 simultaneously or alternately on the fastened object A side and the fastened object B side, the fastened objects A and B are tightened, and the bolt itself is firmly tightened without loosening. Fixed.

In the fifth embodiment shown in FIG. 9, since the outer peripheral surface (tool engaging surface) of the main body head 12 and the nut 13 needs to be held by a tool, the material itself needs to be made of a hard material, and a space for applying the tool is necessary. It is.
On the other hand, in the sixth embodiment of FIG. 10, the end of the bolt main body is enlarged by the diameter-expanding member 31 pushed by the sub bolt 21, so that the ring member 13 E is difficult to rotate and is held by a tool or the like. There is no need. Therefore, since it is not necessary to use a hard material such as a nut, it is possible to use the ring member 13E made of a material that can be slightly elastically deformed to maintain the tightening force more firmly. Even if there is no space for hitting the tool, the sub bolt 21 can be tightened with a smaller force.

As described above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the above-described embodiment, and various modifications can be made without changing the gist of the invention.

10, 10A to 10E ...

Bolt

11, 11B to 11C, 51 ... Bolt body 11a ... Shaft portion 11b ... Shaft hole 11c ... Spiral groove (screw portion)
11d, 51d ... conical space 11e ... slit 11f ... recess 12 ... main body head 12a ... tool engaging portion 12b ... recess 13 ... nut 13E ... ring member 14 ... washer 21 ... sub bolt 21a ... sub bolt head ( Locking head)
21b, 31e ... Sub-bolt shaft (fastening shaft)
21c ... Tip screw portion 21d ...

Tool engaging portion

31, 31A ... Diameter-expanding member 31a ... Frustum-shaped side surface 31b ... Connection hole 31c ... Blade member (locking projection, rotation prevention means)
31f ... truncated cone part 31g ... spiral groove (screw part)
41 ... Nut

Claims

The shaft core portion has a shaft hole, and has a frustoconical space that is widened so that at least one end portion in the shaft core direction of the shaft hole is closer to the end, and the cylindrical portion in which the space is formed On the other hand, a bolt body in which a plurality of slits for diameter expansion are formed at positions in the circumferential direction;
A diameter-enlarging member that is disposed in the space and is prevented from rotating with respect to the bolt body by the rotation preventing means, and has a truncated cone-shaped side surface that contacts the inner wall of the space and a connecting hole;
A screw part that is inserted into the shaft hole of the bolt main body and the connecting hole of the diameter-expanding member and is screwed to the screw part on the inner surface side of the shaft hole is provided on at least a part of the outer peripheral surface. A fastening shaft that moves a diameter member in the space and applies a diameter expansion force to the bolt body;
With bolts.
The bolt according to claim 1, wherein as the rotation preventing means, a locking projection that engages with the slit to prevent rotation is provided on a side surface of the diameter-expanding member.
The bolt according to claim 2, wherein the locking protrusion is a protrusion formed on a side surface of the diameter-expanding member and extending in parallel with the axis.
The bolt body, the shaft hole penetrates the shaft core portion, a body head is provided on one side portion of the penetrating shaft hole, and a sub bolt can be accommodated therein.
The secondary bolt is
The fastening shaft portion inserted into the shaft hole from the body head side with respect to the bolt body,
A locking head provided on one side of the fastening shaft in the axial direction, housed in the main body of the bolt body and locked in the axial direction;
The threaded portion on the distal end side of the fastening shaft portion not provided with the locking head is screwed and coupled with the threaded portion on the inner peripheral surface of the coupling hole of the diameter-expanding member, and accommodated in the bolt body The distal end portion is configured to be able to expand the diameter by each slit provided at the distal end portion of the fastening shaft portion by the movement of the diameter-expanding member in the space when the sub bolt is rotated. The bolt according to any one of 3 above.
The bolt according to claim 4, wherein a recess is formed in the head of the bolt main body to receive the locking head of the auxiliary bolt.
The bolt body has the bottomed shaft hole in which a thread portion is formed on an inner peripheral wall in at least one of both end portions in the axial direction.
With respect to the bottomed shaft hole, the auxiliary bolt having the fastening shaft portion in which the screw portion is formed on the outer peripheral surface can be screwed and inserted by rotating the shaft.
The frustoconical shape on the opening side of the bolt body opposite to the bottom of the shaft hole, wherein the expanding member having the connecting hole penetrating in the axial direction is formed on the inner peripheral wall with a threaded portion. And the plurality of slits are formed,
The secondary bolt has a locking head on one side of the fastening shaft portion, and when the shaft rotates, the locking head presses the diameter-expanding member, and the diameter-expanding member is pushed into the bottom of the shaft hole in the space. The bolt according to any one of claims 1 to 3, wherein the bolt is configured to be movable in a side direction.