JP2003013933A - Fastener - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide bolts and nuts capable of fastening a bolt and a nut, further, preventing the bolt and nut from getting loose and dropping out and imparting safety that they can not easily removed by a spanner or a wrench in markets and mildness which does not hurt human beings and neat appearance. SOLUTION: The fastener is formed of a nut in which a protrusion is provided at one end of a shaft having a male screw part and a wrench groove is formed in a large diameter head provided at the center of the other end of the shaft, and a bolt provided with a decoration part at the outer peripheral edge of the head, a screw groove and an engaging groove are formed at the inner peripheral face of the cylindrical shaft, a wrench groove is formed in the large diameter head provided in the other end of the cylindrical shaft, and a nut provided with a decoration part at the outer peripheral edge constitutes the fastener. The shaft of the bolt is screwed in the cylindrical shaft of the nut, and the protrusion of the shaft is positioned in the engaging groove, to fasten the bolt and the nut. The protrusion is squashed and engaged in the engaging groove by the fastening force of.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fastener for preventing bolts and nuts from falling off, which is used for connecting buildings with severe vibration such as bridges and protective walls for highways.

[0002]

2. Description of the Related Art Conventionally, bolts and nuts used to connect construction members such as bridges and protective walls for highways are used for a long time due to railways and vehicles passing through bridges and highways. In order to prevent the bolts and nuts from loosening or coming off due to the intense vibration or shock applied to them, a wide variety of bolts and nuts with a loosening prevention function and a fall prevention function are used.

For example, in the A bolts and nuts 1 and 5 shown in FIG. 16, a hole 3 is provided in the shaft portion 2 of the bolt 1 in a direction substantially perpendicular to the shaft portion 2, and a split pin 4 can be inserted into the hole. It is formed on. After the object S to be connected is fastened with the A bolts and nuts 1 and 5, the split pin 4 is inserted into the hole 3 of the shaft portion 2 of the bolt 1. Even if the tightened nut 5 loosens due to vibration or shock and moves along the shaft portion 2, the nut 5 is locked by the split pin 4 to prevent the nut 5 from falling off the shaft portion.

However, when connecting the objects S to be connected by using the A bolts and nuts 1 and 5, there are many places where the bolts and nuts are fastened. Forgetting to insert the cotter pin 4 into, and cotter pin 4 coming off due to corrosion due to aging,
It was difficult to completely prevent the nut from falling off using the split pin 4.

B bolts and nuts 10 and 15 shown in FIG.
Has a groove 12 having a diameter smaller than the diameter of the shaft portion formed in the circumferential direction at a substantially tip end of the shaft portion 11 of the bolt 10. After tightening the object to be connected S with these B bolts and nuts 10 and 15,
Even if the nut 15 loosens due to vibration and moves along the shaft portion 11, the thread groove is cut by the groove portion 12, so the nut 15 does not move and is locked in the groove portion 12 to prevent the nut from falling off. is doing.

However, since the bolt 10 constituting the B bolts and nuts 10 and 15 only has the groove portion 12 in the shaft portion 11, the nut 15 loosened by vibration can be temporarily locked, When the loosened connecting portion is greatly shaken due to severe vibration or shock, the nut 15 may pass through the groove portion 12 and fall off.

C bolts and nuts 20 and 2 shown in FIG.
5 is a normal bolt 20 and a nut 25 having a loosening function
After the bolt 20 is inserted through the object S to be connected, the nut 25 is fastened to the shaft portion 21 of the bolt through the spring washer 26 and the washer 27. This C bolt and nut 20,
It is fastened to 25 through a spring washer 26 and a washer 27. Therefore, in the unlikely event that the nut 25 loosens due to vibration, the shaft 2
Even if you try to move in the opposite direction of 1, the spring washer 2
6 always repels the nut 25 to increase the frictional resistance with the thread groove of the shaft portion 21 to prevent the nut 25 from moving and falling off.

However, the C bolts and nuts 20 and 25 which are fastened via the spring washer 26 and the washer 27 are easily loosened by repeated repeated violent vibrations and shocks over time, and once loosened, they are locked to the shaft portion. Since it has no means, it may easily fall off the shaft portion 25.

[0009]

As described above, the various bolts and nuts used for connecting buildings to which severe vibrations and shocks are applied are liable to come loose and fall off, which is dangerous. In addition, the outer peripheral surface of the bolts and nuts is provided with a polygonal chamfered locking part, so it can be easily loosened with a commercially available spanner or wrench, and it is easy to steal or destroy parts. It was dangerous. In addition, since bolts and nuts are exposed on guardrails and balustrades on bridges, it is very dangerous because it is easy to get injured or get caught on clothes by a nut having a sharp locking portion. Since the bolt / nut engaging portion is formed only for the purpose of tightening or loosening the object to be connected, it has no design feature.

According to the present invention, the bolts and nuts are tightened, and at the same time, the bolts and nuts are prevented from being loosened and prevented from falling off.
The purpose is to provide safety that nuts cannot be easily removed with a commercially available spanner or wrench, gentleness that does not hurt people, and beautiful-looking bolts and nuts.

[0011]

SUMMARY OF THE INVENTION The present invention is to solve the above problems. The invention of claim 1 provides a deformable protrusion at one end of a shaft portion having a male screw portion, A wrench groove is provided on a large-diameter head part that is hooked on the other end of the part, and a bolt having a decorative part on the outer surface of the head part and a thread groove on the inner peripheral surface of the cylinder shaft with one end opened A stopper groove is provided, a wrench groove is provided in a large-diameter head formed at the other end of the cylinder shaft, and a nut having a decorative portion is provided on the outer surface of the head, and the nut is provided in the cylinder shaft of the nut. The shaft portion of the bolt is screwed together, the protrusion of the shaft portion is located in the locking groove portion, and the bolt and nut are tightened, and the protrusion portion is locked in the locking groove portion by the tightening force of the bolt and nut. It is characterized by being crushed and locked. Further, the protrusion of the bolt is characterized in that a mortar shape is formed inside the end of the shaft through a neck having a small diameter, and a slit groove is provided on the end face of the protrusion. Furthermore, the locking groove is
It is characterized in that it is formed with a diameter larger than the inner diameter of the thread groove provided in the cylindrical shaft.

Therefore, by simply tightening the bolts and nuts together, the protrusions can be crushed and locked in the locking grooves to prevent the bolts and nuts from loosening and falling off.

According to a fourth aspect of the present invention, a shaft portion having a male screw portion is provided at one end with a projecting portion which is deformable by bending the tip into a trumpet shape, and has a large diameter provided at the other end of the shaft portion. A wrench groove was formed on the head, and a bolt having a decorative portion on the outer surface of the head, a deformable member formed of a flexible member that fits into the protrusion of the bolt, and one end opened A nut having a thread groove and a locking groove portion on the inner peripheral surface of the cylinder shaft, a wrench groove formed on a large-diameter head formed at the other end of the cylinder shaft, and a nut having a decorative portion on the outer surface of the head. The screw shaft portion of the bolt is screwed into the tubular shaft of the nut, the protrusion of the shaft portion and the deformable member are positioned in the locking groove portion, and the bolt and nut are tightened. It is characterized in that the protrusion and the deformable member are crushed and locked in the locking groove by the tightening force of the nut. In addition, the protrusion of the bolt is tubular and has a tip that expands into a trumpet shape and is bent to form a slit groove on the end face of the protrusion, and a deformable member is attached to the protrusion.
Further, the deformable member is characterized by being made of a hard synthetic resin, a hard synthetic rubber, a non-ferrous metal, or a soft metal material.

Therefore, when the bolts and nuts are fastened to each other and the projection is crushed and locked in the locking groove, the deformation member is attached to the peripheral edge of the projection so that the deformation member locks the nut. It is possible to prevent the rattling of the meshing portion of the bolt and the nut, the loosening of the nut, and the dropping of the nut by expanding the groove and eliminating the gap in the locking groove.

According to a seventh aspect of the present invention, a deformable tubular protrusion is provided at one end of a shaft portion having a male screw portion, and an inner peripheral surface is provided on a large-diameter head provided at the other end of the shaft portion. In addition to providing a polygonal wrench groove, a bolt having a decorative portion on the outer surface of the head and a thread groove on the inner peripheral surface of the cylinder shaft having one end opened, and the other end of the cylinder shaft are provided. A wrench groove having a polygonal inner peripheral surface was provided on the large-diameter head, a decorative portion was provided on the outer surface of the head, and a hole communicating with the inside of the cylinder shaft was provided on the inner bottom surface of the wrench groove. It consists of a nut, and the bolt shaft is screwed into the nut's cylinder shaft to tighten the bolt and nut, and the tip of the protrusion inserted through the nut hole into the wrench groove is spread with a jig. It is characterized by caulking. Further, the protrusion of the bolt is formed in a tubular shape having a diameter smaller than the outer diameter of the shaft portion.

Therefore, since the structure of the projecting portion of the bolt is simple and can be manufactured at low cost, the cost is reduced and it is economical, and the projecting portion is surely crushed while visually confirming directly by using a jig. As a result, it is possible to prevent the nut from slackening and falling off, and to form a bolt and nut that has a beautiful appearance and safety that cannot be easily removed with a commercially available spanner or wrench.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a fastener according to the present invention will be described. FIG. 1 is a side view in which a first bolt showing a first embodiment of the present invention is partially broken, and FIG. 1 is a bottom view of FIG. 1, FIG. 3 is a partially cutaway side view of the first nut showing the first embodiment, and FIG. 4 is a front view of the first nut.

In FIGS. 1 and 2, the first bolt 31 is made of a metal material such as steel, stainless steel, and aluminum. The head 32 of the bolt has an outer peripheral edge formed in a substantially arcuate shape and a head. Decorative part 3 with a smooth outer surface
3 is provided. A wrench groove 35 having a polygonal inner surface, preferably a 12-sided inner surface, is provided at the center of a flat portion 34 provided at the center of the upper surface of the head portion 32, and the circumference of a shaft portion 36 connected to the head portion 32 is provided. A male screw portion 37 is formed on the surface, and a protruding portion 38 is formed at the end of the shaft portion so as to have flexibility and elasticity.
Is provided.

The protrusion 38 is formed by forming the neck portion 39 on the shaft side into a small diameter so that the inner surface has a mortar shape and the outer peripheral surface expands into a trumpet shape, and the slit groove 40 is provided at the rear end of the protrusion portion. Is provided. By providing the slit groove 40 at the rear end of the protrusion 38 and forming the outer peripheral edge into the trumpet-shaped surface,
It can be easily crushed and deformed by the pressure applied to the rear end of the protrusion.

In FIGS. 3 and 4, the first nut 41 is made of a metal material such as steel, stainless or aluminum, and has a thread groove 43 on the inner surface of the cylinder shaft 42 with one end opened.
And a locking groove portion 44 are provided through a hooking step portion 44a.
The locking groove portion 44 is formed to have a diameter slightly larger than the inner diameter of the screw groove 43 so that the protrusion portion 38 provided at the end portion of the shaft portion 36 of the first bolt can be crushed and accommodated.

On the outer peripheral edge of a slightly larger diameter head portion 45 provided at the other end of the cylinder shaft 42, a decorative portion 46 is provided which is formed in a substantially arcuate shape and has a smooth outer surface. A wrench groove 48 having a polygonal inner surface, preferably a twelve-sided surface, is formed at the center of a flat portion 47 provided at the center of the upper surface of the portion.

Next, the first bolt / nut 3 according to the present invention.
Explaining the operation of Nos. 1 and 41, for example, as shown in FIG. 5, the cylinder shaft 42 of the first nut 41 is inserted into the hole X of the object S to be connected, and the bolt 31 is inserted from the opposite side of the object S to be connected. The shaft portion 36 is inserted, and the male screw portion 37 and the thread groove 43 of the cylindrical shaft are screwed together. Then, wrenches (not shown) are fitted into the wrench grooves 35 and 48 of the first bolts and nuts 31 and 41, respectively, and rotated in the opposite directions to be tightened.

By the tightening force of the first bolts and nuts 31 and 41 caused by rotating the wrench, the tips of the projections 38 located in the locking groove 44 are pressed against the slit groove 40 while being crushed by the inner wall. When it is expanded and deformed, it is pressure-bonded to the inner peripheral surface of the locking groove portion 44 and is locked and fixed to the locking step portion 44a.

By providing the slit groove 40 on the end face of the protrusion 38, when the protrusion is crushed, since the peripheral surface has a trumpet shape, it can be spread radially. Therefore, the protrusion 38 provided at the end of the shaft portion can be crimped into the locking groove portion 44, and can be locked to the locking step portion 44a to be firmly fixed.

At the same time as the object S to be connected is fastened with the first bolts and nuts 31 and 41, the projection 38 in the cylinder shaft 42 is deformed by the tightening force of the bolts and nuts and is crimped into the locking groove 44. Since it is locked, there is no need to perform work to prevent the bolts and nuts from falling off, and work efficiency can be improved.

As described above, in the first bolts / nuts 31 and 41 to which the object S to be connected is fastened, the protrusion 38 has the engaging groove portion 4 as described above.
Since it spreads in 4 and is crimped and locked, it can be prevented from loosening or falling off even if a strong vibration or shock is applied to the building for a long time.

However, the first bolts and nuts 31, 4 are
The crushing deformation of the protrusion due to the mutual clamping force of
There is a case where a gap 8 is formed between a part of the deformed protrusion 38 and the inner surface of the locking groove 44 without the 8 spread over the entire inner surface of the locking groove 44. If a gap is formed in the locking groove portion 44, rattling occurs between the tightened bolt and the nut, causing slack.

As shown in FIG. 7, in order to prevent the loosening due to the rattling as described above, when the bolt is inserted into the object S to be connected, the object S to be connected and the head of the bolt 31 are
The spring washer 26 and the washer 27 are fastened to each other to prevent rattling between the bolt and the nut due to the elastic force of the spring washer.

A fastener according to a second embodiment of the present invention will be described. FIG. 8 is a partially cutaway side view of the second bolt of the present invention, and FIG. 9 is a side view of the second bolt using the second bolt. It is sectional drawing which shows the state which connected the connection thing.

In FIGS. 8 and 9, the second bolt 51 is made of a metal material such as steel, stainless steel, aluminum or the like, and the head 52 of the bolt has an outer peripheral edge formed in a substantially arcuate portion. A decorative portion 53 having a smooth outer surface of the head is provided. Flat portion 54 provided on the upper surface of this head
A wrench groove 55 having an inner peripheral surface formed in a polygonal shape, preferably a 12-sided shape, is provided at the center of the shaft portion 56 provided in the head portion 52.
A male screw portion 57 is formed on the peripheral surface of and the projection portion 58 is integrally formed at the tip of the shaft portion.

The protrusion 58 is formed in a tubular shape having a diameter slightly smaller than the outer diameter of the shaft portion 56, a tapered tubular trumpet portion is provided at the rear end, and a slit groove 59 is provided on the end face of the protrusion. Has been formed. By providing the trumpet-shaped slit groove 59 provided at the rear end of the protruding portion 58, it is easily deformed by the pressure applied to the end surface of the protruding portion, and the end portion of the protruding portion 58 is flexible. Further, a deformable member 60 formed of a member having elasticity is attached.

The deformable member 60 is formed of a soft iron material having a flexibility and elasticity, a non-ferrous metal material, a hard synthetic resin material, a hard synthetic rubber, etc., and has a diameter slightly smaller than the outer diameter of the shaft portion 56. And is fitted to the protrusion 58.

When the object S to be coupled is connected using the second bolt 51 and the first nut 41, for example, as shown in FIG. 9, the cylinder of the first nut 41 is placed in the hole X of the object S to be coupled. While inserting the shaft 42, the second side from the opposite side of the object S to be connected
The shaft portion 56 of the bolt 51 is inserted, and the male screw portion 57 is screwed into the thread groove 43 of the cylindrical shaft 42.

Next, the second bolt 51 and the first nut 4
Wrench (not shown) in each wrench groove 55, 48
And then rotate in opposite directions to tighten. By the tightening force of the second bolt 51 and the first nut 41 by the wrench, the tips of the deforming member 60 and the protrusion 58 in the locking groove portion 44 are radially deformed and locked while being crushed by the inner wall of the locking groove portion 44. It is crimped to the entire inner surface of the groove portion 44, and the locking step portion 44a
Hang on.

In particular, since the deformable member 60 is flexible and elastic and can be safely deformed, the locking groove portion is formed by the tightening force of the second bolt 51 and the first nut 41. 44
Can be crimped over the entire inner surface of the. By pressing the deformable member 60 against the inner surface of the locking groove portion 44, the gap between the locking groove portion and the protrusion 58 can be closed, so that rattling of the bolts and nuts can be prevented and the deformable member 60 can be prevented.
And the protruding portion 58 spread in the locking groove portion 44 and are crimped,
In addition, since it is locked to the latching step portion 44a, it is possible to prevent the bolts and nuts from loosening or coming off even if the building is subjected to severe vibration or impact for a long period of time.

A third embodiment of the present invention will be described. FIG. 10 is a sectional view of a third bolt of the present invention, FIG. 11 is a bottom view of FIG. 10, and FIG. 12 is a sectional view of a second nut. Thirteen
[Fig. 4] is a plan view of a second nut.

In FIG. 10, the third bolt 61 is formed of a metal material such as steel, stainless steel or aluminum. The head 62 of the bolt has an outer peripheral edge formed in a substantially arcuate shape and a head. A decorative portion 63 having a smooth outer surface is provided, and a wrench groove 65 having a polygonal, preferably dodecagonal inner peripheral surface is provided at the center of a flat portion 64 formed at the center of the upper surface. Shaft 6 provided on the head 62
A male screw portion 67 is formed on the peripheral surface of 6, and a projection 68 is formed at the end of the shaft portion in a tubular shape having a diameter slightly smaller than the outer diameter of the shaft portion.

The second nut 71 is made of steel, stainless steel,
Cylindrical shaft 72 made of metal material such as aluminum material
A thread groove 73 is provided on the inner peripheral surface of the head, the outer peripheral edge of a large-diameter head 75 provided at the end of the cylindrical shaft 72 is formed into a substantially arc-shaped portion, and the outer surface of the head is formed into a smooth surface. A makeup section 76 is provided. A wrench groove 78 having an inner peripheral surface having a polygonal shape, preferably a dodecagonal shape is provided in the center of a flat portion 77 provided on the upper surface, and the inner bottom surface of the wrench groove has a hole 7 communicating with the cylinder shaft.
9 is formed.

Next, the case where the third bolt 61 and the second nut 71 according to the present invention are used for tightening will be described. For example, as shown in FIG.
The cylindrical shaft 72 of the second nut 71 is inserted therein. Then,
The shaft portion 66 of the third bolt 61 is inserted from the side opposite to the connected object S, and the male screw portion 67 and the thread groove 73 of the cylindrical shaft are screwed together. Further, the respective wrenches engaged with the respective wrench grooves 65, 78 of the third bolt 61 and the second nut 71 are rotated in the opposite directions to be tightened.

With a wrench, the third bolt 61 and the second bolt 61
When the object S is fastened with the nut 71, the protrusion 68 of the shaft portion 66 enters the wrench groove 78 from the hole 79 of the second nut 71 and is positioned. Insert the tip of a jig Y such as a punch, a wrench, or a hydraulic tool into the recessed portion provided inside the tip of the protrusion 68 located in the wrench groove 78, push and spread it, and crimp it, and then the inner bottom surface of the wrench groove 78. (Fig. 15).

The operator visually confirms directly with the projection 68
Since it can be crimped and locked in the wrench groove 78 by the jig Y, it is possible to reliably prevent the bolts and nuts from being loosened and from coming off.

The above-mentioned first, second and third bolts 31, 51,
61 and each head 3 such as the first and second nuts 41 and 71
Decorative portions 33, 4 each having a relatively large area provided on the upper surface and the peripheral surface of 2, 45, 52, 62, 75 are smooth surfaces.
6, 53, 63, and 76 can be designed with beautiful heart-shaped or cloud-shaped shapes, and you can enjoy the variations. Furthermore, by eliminating the sharp locking part from the outer peripheral surface of each head, there is no risk of injury or clothes hanging even if it is attached to guardrails or balustrades of bridges in addition to the building. Become kind to

Furthermore, the above-mentioned first, second and third bolts 3
The inner peripheral surface of the wrench groove provided on each head of the first, the first nut 51, the first nut 61, the second nut 41, and the first nut 71 has a polygonal shape, preferably 12
By forming it into a planar shape, commercially available spanners and wrenches do not have a dodecagonal shape, and therefore the nut cannot be easily rotated, making removal difficult and improving safety. .

[0044]

According to the first aspect of the invention, the protrusion provided at the tip of the shaft portion of the first bolt by the tightening force of the first bolt and nut is provided in the locking groove portion provided in the cylindrical shaft of the first nut. Since it can be deformed by being screwed into and crushed, the bolts and nuts can be efficiently tightened and the bolts and nuts can be securely tightened and prevented from falling off simply by tightening the bolts and nuts. According to a fourth aspect of the invention, when the second bolt is attached to the protrusion provided at the tip of the shaft portion with the deformable member formed of a member having flexibility and elasticity, the object to be connected is fastened, Since the projection and the deformable member spread and come into close contact with the locking groove in the cylinder shaft of the first nut, the rattling of the bolt and nut is prevented, and the bolt and nut are securely loosened and prevented from falling off. Can be planned. Claim 7
In the invention, when the object to be connected is fastened with the third bolt and the second nut, the projection provided on the tip of the shaft portion of the third bolt is projected into the wrench groove of the second nut, and the tip of the projection is provided. Since it is spread with a jig such as a punch and caulked in the wrench groove to prevent the bolts and nuts from loosening and from falling off, the structure of the bolt protrusions is simple and inexpensive to manufacture, and the cost is low. Since it is possible to reliably crush the protrusion using a jig, it is possible to prevent the nut from loosening and falling off. By forming the wrench groove of the bolt and nut into an irregular polygonal surface, safety that can not be easily removed with a commercially available spanner or wrench, and by removing the protruding part from the cosmetic part it does not hurt people so it is environmentally friendly It is possible to provide bolts and nuts that are gentle and have a beautiful appearance.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view of a first bolt showing a first embodiment of the present invention.

FIG. 2 is a bottom view of FIG.

FIG. 3 is a partially cutaway side view of a first nut forming a pair with the first bolt shown in FIG.

FIG. 4 is a front view of a first nut.

FIG. 5 is a cross-sectional view showing a state before the protrusion is crushed when the object to be connected is fastened using the first bolt and the first nut.

FIG. 6 is a cross-sectional view showing a tightened state after the protrusion is crushed when the object to be connected is tightened using the first bolt and the first nut.

FIG. 7 is a cross-sectional view showing a state in which a washer and a spring washer are attached to and fastened to a first bolt and a first nut.

FIG. 8 is a side view in which a second bolt is partially broken.

FIG. 9 is a cross-sectional view showing a tightened state after the protrusion and the deformable piece are crushed when the object to be connected is tightened using the second bolt and the first nut.

FIG. 10 is a sectional view of a third bolt.

FIG. 11 is a bottom view of the third bolt.

FIG. 12 is a sectional view of a second nut.

FIG. 13 is a plan view of a second nut.

FIG. 14 is a cross-sectional view showing a tightened state before the protrusion is crushed by the jig when the object to be connected is tightened using the third bolt and the second nut.

FIG. 15 is a cross-sectional view showing a tightened state after the protrusion is crushed by the jig when the object to be connected is tightened using the third bolt and the second nut.

FIG. 16 is an explanatory view showing a usage state of a conventional A bolt / nut having a nut falling prevention function.

FIG. 17 is an explanatory view showing a usage state of a conventional B bolt / nut having a nut falling prevention function.

FIG. 18 is an explanatory diagram showing a usage state of a conventional C bolt / nut having a nut falling prevention function.

[Explanation of symbols]

31 First bolt 32 heads 35 wrench groove 36 Shaft 37 Male thread 38 Projection 39 neck 40 split groove 41 First Nut 42 cylinder shaft 43 thread groove 44 Locking groove 45 heads 48 wrench groove 51 Second bolt 52 head 55 wrench groove 56 Shaft 57 Male thread 58 Projection 59 Gutter 60 Deformable member 61 Third bolt 62 head 65 wrench groove 66 Shaft 67 Male thread 68 Projection 71 Second nut 72 cylinder axis 73 thread groove 75 head 78 wrench groove 79 holes S Connected material

Claims (8)

[Claims] 1. A deformable protrusion is provided at one end of a shaft portion having a male screw portion, a wrench groove is provided in a large-diameter head portion formed at the other end of the shaft portion, and an outer surface of the head portion is provided. A bolt having a decorative portion, a thread groove and a locking groove portion are provided on the inner peripheral surface of the cylinder shaft having one end opened, and a wrench groove is provided on a large-diameter head formed at the other end of the cylinder shaft. A nut having a decorative portion on the outer surface of the head, the shaft portion of the bolt is screwed into the tubular shaft of the nut, and the projection of the shaft portion is positioned in the locking groove portion. A fastening tool characterized in that a bolt and a nut are tightened, and the protrusion is crushed and locked in the locking groove by the tightening force of the bolt and the nut. 2. The protrusion of the bolt is characterized in that a mortar-like shape is formed inside at an end of a shaft through a neck having a small diameter, and a slit groove is provided on an end face of the protrusion. The fastener according to Item 1. 3. The fastener according to claim 1, wherein the locking groove portion is formed to have a diameter larger than an inner diameter of a screw groove provided in the cylinder shaft. 4. A shaft portion having a male screw portion is provided at one end with a protrusion formed by bending the tip into a trumpet shape, and a large diameter head provided at the other end of the shaft portion is provided with a wrench groove. A bolt having a decorative portion on the outer surface of the head, a flexible deformable member that fits into the protrusion of the bolt, and a thread groove on the inner peripheral surface of the cylinder shaft with one end opened. And a locking groove portion, a wrench groove is formed on a large-diameter head portion formed on the other end of the cylinder shaft, and a nut having a decorative portion on the outer surface of the head portion. The shaft portion of the bolt is screwed in, the protrusion portion of the shaft portion and the deformable member are positioned in the locking groove portion, and the bolt and nut are tightened, and the protrusion portion and the nut are tightened by the tightening force of the bolt and nut. A fastening tool characterized in that a deformable member is crushed and locked in a locking groove portion. 5. The protrusion of the bolt has a tubular shape, the tip of which is expanded like a trumpet and bent to form a slit groove on the end face of the protrusion, and a deformable member is attached to the protrusion. The fastener according to claim 4, wherein 6. The fastener according to claim 4, wherein the deformable member is a hard synthetic resin, a hard synthetic rubber, a non-ferrous metal, or a soft metal material. 7. A wrench having a deformable tubular projection provided at one end of a shaft portion having a male screw portion, and having a polygonal inner peripheral surface on a large-diameter head provided at the other end of the shaft portion. A large diameter head provided with a groove and a bolt having a decorative portion on the outer surface of the head, and a thread groove on the inner peripheral surface of a cylinder shaft having one end opened, and the other end of the cylinder shaft. A wrench groove having a polygonal inner peripheral surface is formed, a decorative portion is formed on the outer surface of the head, and the inner bottom surface of the wrench groove is a nut having a hole communicating with the inside of the cylinder shaft. The bolt and nut are tightened by screwing the shaft portion of the bolt into the tubular shaft of the nut, and the tip of the protrusion inserted through the hole of the nut into the wrench groove is spread with a jig to prevent caulking. Characterized fasteners. 8. The fastener according to claim 7, wherein the protrusion of the bolt is formed in a tubular shape having a diameter smaller than the outer diameter of the shaft portion.