JP2000087944A - Protection device for fastening part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protection device for a fastening part capable of certainly preventing detachment of a nut member in time of fastening. SOLUTION: Fastened members 1, 2 are fastened to each other with a screw member 3 and a nut member 6. In this state, a nut detachment preventing tool 7 is screwed onto the screw member 3 so as to prevent detachment of the nut member 6. This nut detachment preventing tool 7 mainly comprises a ring body 7b, which accommodates a coil-like spring member 8 of one or more turns toward its inside face with axial movement of the spring member 8 restricted within a prescribed range and has an engaging part 7c detachably engaging with an end part of the spring member 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to protection of a fastening portion of a steel tower or the like in which an iron plate or the like is fastened with a screw member and a nut member so as to protect the nut member in a non-removable state. It concerns the device.

[0002]

2. Description of the Related Art Generally, in order to connect iron plates in a steel tower or the like, a screw member such as a bolt member is inserted into a through hole of both iron plates, a nut is screwed from a tip of the screw member, and a lock nut is further connected. The screw member is screwed and fastened.

However, since the nut and the lock nut are exposed on the surface, the lock nut is loosened by mischief or the like, and the nut is removed from the screw member to release the fastening state between the iron plates. I have.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems and to provide a protection device for a fastening portion capable of reliably preventing the fastening state of the fastening portion from being released by mischief or the like. It is intended to provide.

[0005]

To achieve the above object, a first aspect of the present invention is to prevent the nut member from being removed at a fastening portion where the member to be fastened is fastened by a screw member and a nut member. A protection device for a fastening portion, wherein one or more turns of a coil-shaped spring member are axially moved within a predetermined range on an inner surface side of a ring body in a state where the member to be fastened is fastened with the screw member and a nut member. Regulated and included
A nut removal prevention tool, which is formed by providing an engagement portion detachably engaged with an end of the spring member on the ring body, is rotated in the forward direction while pressing the nut against the end of the screw member, thereby rotating the spring member. , While the end is engaged with the engagement portion, the screw member is advanced while being screwed into the screw portion of the screw member,
In a state where the ring body is in contact with the nut member or the member to be fastened, the ring body is further rotated in the forward direction to further advance only the spring member, and the end of the spring member is moved from the engagement portion. By detaching the ring member, the ring member is freely rotatable in both the forward and reverse directions, and the nut removal preventing device is set in an unremovable state to protect the nut member.

According to a second aspect of the present invention, there is provided a protection device for a fastening portion in which a nut member is prevented from being removed at a fastening portion where a member to be fastened is fastened with a screw member and a nut member. An outer ring body, and a support that is screwed into the screw portion of the screw member and that supports the outer ring body in a rotatable and axially immovable state, wherein the outer ring body and the support A unidirectional rotation transmitting means for transmitting the rotation of the outer ring body only in the screwing direction to the support member and freely rotating the outer ring body in the opposite direction is disposed between the two.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an embodiment of a device for protecting a fastening portion according to the present invention.

FIG. 1 shows a use state of a protection device for a fastening member according to a first embodiment of the present invention. FIG. 1 (a) shows a cap member which is screwed to a bolt member (screw member) to fasten iron plates. FIG. 4B is a cross-sectional view showing a state in which the nut is prevented by the nut removal preventing tool provided with the nut member. FIG. FIG. 2 is a cross-sectional view of the preventive device, and FIG. 3 is a nut member screwed to a bolt member and fastening an iron plate together with the preventive device. FIG. 7 is an explanatory cross-sectional view showing a process of reaching a state in which the screw is freely rotatable in a screwing direction and a direction opposite thereto.

In FIGS. 1A and 1B, reference numerals 1, 2
Is an iron plate used for a steel tower or the like.
2 are fastened to each other by a nut member 6 including a bolt member 3 and a nut 4 and a lock nut 5. That is, iron plates 1 and 2
In a state where the opposing surfaces are in contact with each other, the screw portion 3a of the bolt member 3 is inserted into the bolt insertion holes 1a and 2a of the iron plates 1 and 2, and then the nut 4 is screwed. The iron plates 1 and 2 are screwed together and fastened between the head 3b of the bolt member 3 and the nut member 6.

In the protection device for the fastening portion of the first embodiment, the nut member 6 screwed to the screw portion 3a of the bolt member 3 for fastening the iron plates 1 and 2 as described above, and the through hole 7 in the center portion.
a, and is covered with a nut removal prevention tool (hereinafter, sometimes simply referred to as a prevention tool) 7 having a ring body 7b as a main component, which is integrally formed with a cylindrical cap portion 7p. As shown in FIG. 2, a small protruding edge 7 is provided on the front and rear edges of the inner side of the ring 7b of the preventer 7.
c and 7d are protruded, and approximately 2 are provided on the inner surface side of the ring body 7b.
A coiled spring member 8 is provided. The spring member 8 has a diameter in its natural state,
Is slightly smaller than the diameter of the screw 3a and screwed into the screw portion 3a so as to embrace it. The axial movement of the spring member 8 is restricted within a predetermined range by the small projecting edges 7c and 7d. Further, at a position near the rear edge of the inner surface of the ring body 7b,
A protruding portion 7e abutting on the rear end of the spring member 8 is provided. The projection 7e may be formed integrally with the ring 7b, or may be formed by implanting a pin in the ring 7b.

As shown in FIG. 3 (a), the preventer 7 first covers the nut member 6 screwed to the screw portion 3a of the bolt member 3 in the direction of the arrow so as to cover the nut member 6 with the cap portion 7p. As shown in FIG. 3 (b), when the prevention member 7 is rotated in the screwing direction as shown by the arrow while being pressed, the spring member 8 becomes a portion of the screw portion 3a of the bolt member 3 protruding from the lock nut 5. The screw portion 3a is screwed so as to fit into the screw portion 3a, and the rear end portion of the spring member 8 is pushed by the projection portion 7e. Forward while rotating to the left).

Further, as shown in FIG. 3 (c), the ring member 7b provided with the cap portion 7p and the spring member 8 are advanced in the screwing direction until the tip of the preventer 7 comes into close contact with the iron plate 2. When the preventer 7 is further rotated in a state of being in close contact with the iron plate 2, the ring body 7 b having the cap portion 7 p is restrained from moving in the screwing direction by the iron plate 2,
Only the rotational force is transmitted to the spring member 8, and FIG.
As shown in (1), only the spring member 8 advances further along the screw portion 3a.

By continuing to rotate further, FIG.
As shown in FIG. 7, the rear end of the spring member 8 separates from the projection 7e. In this state, the ring body 7b provided with the cap portion 7p freely rotates in both the forward and reverse directions and idles.

As a result, the ring member 7b having the cap portion 7p is restrained from moving in the axial direction by the small protruding edge 7c engaging with the spring member 8 fixed so as to be embraced by the screw portion 3a. In addition, the ring body 7b rotates idle in any direction, and cannot rotate. Therefore, it is impossible to remove the preventive member 7, and the ring member 7b is covered with the preventive member 7. The nut member 6 cannot be removed.

Therefore, the nut member 6 screwed to the bolt member 3 to fasten the iron plates 1 and 2 cannot be removed from the bolt member 3 due to mischief or the like, and the fastening state of the iron plates 1 and 2 is released. Can be prevented, and the tower can be prevented from becoming dangerous.

FIG. 4 is a sectional view of a principal part showing a protection device for a fastening part according to a second embodiment, and FIG. 5 is a sectional view of a principal part showing a protection device for a fastening part of another example. Note that the same members and the same portions in the protection device for the fastening portion according to the first embodiment described above are denoted by the same reference numerals.

The basic structure of the protection device for the fastening portion of the second embodiment and another example is the same as that of the first embodiment, and the operation for protecting the fastening portion is basically the same. The difference is
As shown in FIGS. 4 and 5, the sliding spacer 1 is attached to the lock nut 5 side of the ring body 7 b of the nut removal preventing tool 7.
4 and 14A are attached, so that the ring member 7b at the time of reverse rotation surely idles with respect to the spring member 8.

That is, in the protection device for the fastening portion according to the second embodiment shown in FIG. 4, a ring-shaped sliding spacer 14 is attached to the inner surface of the ring body 7b on the lock nut 5 side by a retaining ring 15. In the protection device for the fastening portion shown in FIG. 5, the lock nut 5 on the inner surface of the ring portion 7b on the screw portion 3a side is provided.
A ring-shaped sliding spacer 14A is disposed along the annular protrusion 7c protruding inward toward the side.

FIG. 6 shows a protection device for a fastening portion according to a third embodiment. Nut removal prevention tool 7 of the third embodiment
D does not have a function corresponding to the cap part 7p of the first embodiment, and does not have a function of covering the nut member 6. However, also in the third embodiment, the prevention tool 7D is configured to include the same ring body 7b, small protruding edges 7c and 7d, a spring member 8, and a projection 7e as in the first embodiment. As shown in FIG.
When the ring body 7b is further rotated while the tip end surface of the ring member 7 is in contact with the lock nut 5, the rear end of the spring member 8 is separated from the protrusion 7e, and the ring body 7b freely rotates in both forward and reverse directions. The nut members 5, 6
Can not be removed. That is, when the nut members 5 and 6 are rotated in the loosening direction, the nut members 5 and 6 come into contact with the ring body 7b, and the screw portion 3a has a double nut effect, so that the nut members 5 and 6 cannot be further rotated in the loosening direction. The nut members 5 and 6 cannot be removed.

FIG. 7 shows a protection device for a fastening portion according to a fourth embodiment. FIG. 7A shows a case where a nut member screwed to a bolt member to fasten iron plates is covered with a nut removal prevention tool provided with a cap portion. FIG. 8B is a cross-sectional view illustrating a state in which the nut member is covered with the preventive member and the preventive member is freely rotatable in the screwing direction of the nut member and the opposite direction, and FIG. FIG. 9 is a front sectional view of a spring member used for a protection device of a fastening portion according to a fourth embodiment, and FIG. 9 is a partial cross-sectional view of the preventer showing a cutout recess into which an outwardly bent protrusion of the spring member is engaged. Note that the same members and the same portions in the first embodiment described above are denoted by the same reference numerals, and description thereof will be omitted.

In the protection device for the fastening portion according to the fourth embodiment, as shown in FIGS.
A part of the inner surface of the ring body 7b is formed with a notch recess 7m into which an outwardly bent protrusion 8a (see FIG. 8) formed at the end of the spring member 8A can be engaged. On the front side, the spring member 8A
An annular concave portion 7n in which the outwardly bent protrusion 8a is rotatably accommodated is formed (see FIG. 9).

According to the device for protecting a fastening portion of the fourth embodiment, as shown in FIG. 7A, the cap portion 7p of the preventive device 7A is put on the nut member 6 composed of the nut 4 and the lock nut 5. The spring member 8A
The outwardly bent projection 8a is formed by a notch recess 7m of the ring body 7b.
And the spring member 8A is
When the ring body 7b provided with p is rotated in the screwing direction, it rotates integrally with the ring body 7b.

When the ring member 7b provided with the cap portion 7p is in close contact with the iron plate 2 and the ring member 7b is further rotated in the same direction, as shown in FIGS. 7 (a) and 7 (b), the spring member 8A Since the outwardly bent projecting portion 8a is engaged with the notch recess 7m, it advances forward in the screwing direction (leftward in the figure) along the screw portion 3a and is bent outwardly. The protruding portion 8a moves away from the notch recess 7m and moves to the annular recess 7n.

In this state, the ring body 7b provided with the cap portion 7p freely rotates in both the forward and reverse directions and idles. As a result, the ring member 7b is
A is engaged with the small protruding edge 7c to restrict the movement in the axial direction, and the ring body 7b rotates idle in any direction, so that it is impossible to remove the ring body 7b. It becomes possible, and the nut member 6 covered with the cap portion 7p cannot be removed.

Therefore, the nut member 6 screwed to the bolt member 3 to fasten the iron plates 1 and 2 cannot be removed from the bolt member 3 due to mischief or the like, and the fastening state of the iron plates 1 and 2 is released. Can be prevented, and the tower can be prevented from becoming dangerous.

FIG. 10 is a sectional view showing a protection device for a fastening portion according to a fifth embodiment, and FIG. 11 is a sectional view taken along the line AA in FIG. 10. FIG. (B) shows a state when the outer ring body is rotated in the opposite direction. still,
The same members and the same parts in the protection device for the fastening part of the first embodiment described above are denoted by the same reference numerals, and description thereof will be omitted.

In the protection device for a fastening portion according to the fifth embodiment, a disk-shaped support 9 for screwing a nut removal preventing tool 7B to a portion of the screw portion 3a of the bolt member 3 protruding from the lock nut 5; An outer ring body 90 integrally provided with a cylindrical cap portion 90a that covers a nut member 6 composed of a nut 4 and a lock nut 5. Support 9
Supports the outer ring body 90 in a rotatable and axially immovable state. In addition, between the support 9 and the outer ring 90, a one-way rotation that transmits rotation of the outer ring 90 only in the screwing direction to the support 9 and freely rotates the outer ring 90 in the opposite direction. Transmission means is provided.

As shown in FIGS. 10 and 11, the preventing member 7B has an outer ring body 9 having an annular recess 91 formed on the inner periphery.
0, a support 9 which is screwed to the screw portion 3a of the bolt member 3 and has an annular recess 9a on the outer periphery thereof; an annular recess 9a of the support 9 and an annular recess 91 of the outer ring body 90. Bent portion 10a which is disposed inside and is bent outward at one end.
Is a hole 7 formed in the annular recess 91 of the outer ring body 90.
s, and the other end 10b side is bent inwardly. The outer ring body 90 is rotated in the screwing direction. The other end 10b of the body 10 is locked so that the end substantially circular spring body 1
A locking projection 11 is provided on the inner surface of the annular concave portion 9a of the support 9 so as to project outward to rotate the support 9 and the support 9 integrally with the outer ring body 90. The locking projection 11 may be formed by a pin planted on the support 9 as shown in the figure, or may be formed integrally with the support 9.

In the protection device for a fastening portion according to the fifth embodiment, as shown in FIG. 11A, when the outer ring body 90 is rotated in a screwing direction (clockwise in the figure), a substantially circular ended circle is formed. Since the other end 10b of the spring body 10 is bent inward, it is locked to the locking projection 11 projecting outward from the inner surface of the annular recess 9a of the support 9, so that the support 9 is formed of an outer ring. Body 90
And rotate together. The support 9 is a screw 3 of the bolt member 3.
Since it is screwed into a, it advances integrally with the outer ring body 90.

As shown in FIG. 11 (b), when the outer ring body 90 is rotated in the screwing direction (counterclockwise in the figure), the other end 10b of the substantially circular spring body 10 with the end is rotated. Since the locking state of the locking projection 11 is released and the other end 10b of the end-shaped substantially circular spring body 10 rides on the locking projection 11 and rotates, the outer ring body 90 freely rotates. Idle.

Since the outer ring body 90 and the support body 9 are restrained from moving in the axial direction by the end-shaped substantially circular spring bodies 10 interposed in the annular concave portions 91 and 9a, It becomes impossible to remove the ring body 90,
The nut member 6 covered by the cap portion 90a of the outer ring body 90 cannot be removed.

Therefore, the nut member 6 screwed to the bolt member 3 to fasten the iron plates 1 and 2 cannot be removed from the bolt member 3 due to mischief or the like, and the fastening state of the iron plates 1 and 2 is released. Can be prevented, and the tower can be prevented from becoming dangerous.

FIGS. 12A and 12B show a protection device for a fastening portion according to a sixth embodiment, wherein FIG. 12A is a longitudinal sectional view, FIG. 12B is a front sectional view taken along the line BB in FIG. FIG. 14 is a diagram showing the front surface of a retaining ring as a member and the side surface of a backward-facing bent piece;
FIG. 3 is a front view of a support which is a main member. In addition, the same members in the protection device of the fastening portion of the first embodiment described above,
The same portions are denoted by the same reference numerals and description thereof will be omitted.

In the protection device for a fastening portion according to the sixth embodiment, as shown in FIGS. 12 (a) and 12 (b), the nut removal prevention tool 7C is projected from the lock nut 5 of the screw portion 3a of the bolt member 3. And an outer ring body 93 integrally provided with a cap 93a for covering the nut member 6 composed of the nut 4 and the lock nut 5.

The cylindrical outer ring body 93 has an inward flange 7t at the rear end and an annular recess 94 on the inner surface. The support 12 has a small diameter portion 12a at the front portion of the outer peripheral portion and a large diameter portion 12b at the rear portion, and a notch recess 12c for locking is formed at a part of the large diameter portion 12b. (See FIG. 14). The annular concave portion 94 of the outer ring body 93 has a substantially ring-shaped end ring 13 having a rearwardly bent piece 13a (see FIG. 13) which can be engaged with the notch 12c for locking at the outer end. Is rotatably fitted. Further, a projection 14 with which the rear end of the retaining ring 13 abuts is formed in an annular concave portion 94 of the outer ring body 93. In addition, as shown in FIG.
The outer ring body 93 may be formed of a pin or may be formed by integrally projecting a projection on the inner surface of the outer ring body 93.

In the protection device for the fastening portion according to the sixth embodiment, the support 1 is provided between the retaining ring 13 and the inward flange 7t.
Since the second large-diameter portion 12b is arranged in a constrained state, the outer ring body 93 and the support 12 always have the same axial position. When the outer ring body 93 is rotated in the screwing direction, the retaining ring 13 is pushed and rotated by the projections 14, and the rearward bent piece 13 a of the retaining ring 13 is
And the support 12 is rotated in the same direction by being engaged in the locking notch recess 12c of the outer ring body 93.
And rotate together. Conversely, when the outer ring body 93 is rotated in the retreating direction, the rearward bent piece 13a separates from the locking notch recess 12c, and the outer ring body 93 idles.

As a result, the outer ring body 93 can only move forward, but cannot move backward.
The nut member 6 covered by 3 cannot be removed.

Therefore, the nut member 6 screwed to the bolt member 3 to fasten the iron plates 1 and 2 cannot be removed from the bolt member 3 due to mischief or the like, and the fastening state of the iron plates 1 and 2 is released. Can be prevented, and the tower can be prevented from becoming dangerous.

In the fifth and sixth embodiments, the outer ring members 7B and 93 are replaced with cap portions 7p and 7p for covering the nut member 6 like the ring member 7b of the third embodiment shown in FIG. 93a may be omitted.

FIGS. 15A and 15B show a protection device for a fastening portion according to a seventh embodiment, in which FIG. 15A is a longitudinal sectional view and FIG. 15B is a front view showing a spring member as a main part.

In the seventh embodiment, a nut removal preventing tool 7E is provided with a support 12A made of a coil-shaped spring member screwed into a screw portion 3a of a bolt member 3, and an end of the spring member (support) 12A. Outer ring body 93A provided on its peripheral surface with an engagement projection 51 which is detachably engaged with the portion 12m
It is composed of

The coil-shaped spring member 12A comprises:
The bolt member 3 is formed into a plurality of turns that are screwed so as to fit into the screw portion 3a, and its axial movement is regulated by small projecting edges 93c and 93d provided on the outer ring body 93A. Rear end 12m of spring member 12A
Are deformed radially outward as shown in FIG. The end 12m can freely rotate in an annular groove 93n that is recessed on the inner surface rear side of the outer ring member 12A. The outer ring member 12A is provided with a pin-shaped engaging projection 51 so as to face the inside of the annular groove 93n.

When the outer ring body 93A is rotated in the screwing direction, that is, when the outer ring body 93A is rotated in the direction of the arrow in FIG.
And rotates the spring member 12A in the circumferential direction. On the other hand, when the outer ring body 93A is rotated in a direction opposite to the above, the engagement protrusion 51 only deforms the end 12m of the spring member 12A inward in the radial direction, and the engagement protrusion 51 is different from the end 12m. Without engagement, the outer ring body 93A idles while the spring member 12A remains stationary. That is, the engagement projection 51 functions as a one-way rotation transmitting means, and similarly to the fifth and sixth embodiments, in the seventh embodiment, the outer ring body 93A can only move forward, and cannot move backward. And nut removal prevention tool 7
It is a protection device for the fastening portion in which E cannot be removed, and thus the nut member 6 cannot be removed.

The present invention can be configured in various modes in addition to the embodiments described above. For example, as shown in FIG. 16, the head 1 of the bolt member 103 for fastening the iron plates 1 and 2 to each other
The screw shaft 100 protrudes from the screw shaft 03b, and the nut removal preventing tool 7 used in the first embodiment is screwed to the screw shaft 100 to protect the head portion 103b of the bolt member 103. In such a case, the present invention can be applied. In this case, the screw shaft 100 and the head 103
b corresponds to a screw member and a nut member in the claims.

[0045]

As described above, according to the present invention,
The nut member at the time of fastening can be made to be in a non-removable state and can be protected reliably.

[Brief description of the drawings]

FIGS. 1A and 1B show a use state of a protection device for a fastening portion according to a first embodiment of the present invention, wherein FIG. 1A is a cross-sectional view showing a state in which a nut member is covered with a nut removal prevention tool, and FIG. FIG. 9 is a cross-sectional view showing a state in which the ring body is freely rotatable in the screwing direction and the opposite direction while the nut member is covered with the tool.

FIG. 2 is a cross-sectional view of a nut removal preventing tool in the fastening device according to the first embodiment;

FIG. 3 is an explanatory sectional view showing the operation of the protection device for the fastening portion of the first embodiment in order of (a) to (e).

FIG. 4 is a sectional view of a main part showing a protection device for a fastening part according to a second embodiment.

FIG. 5 is a sectional view of a main part showing a protection device for a fastening part according to another example of the second embodiment.

FIG. 6 is a cross-sectional view illustrating a protection device for a fastening portion according to a third embodiment.

7A and 7B are views showing a use state of the protection device for a fastening portion according to the fourth embodiment, in which FIG. 7A is a cross-sectional view showing a state in which a nut member is covered with a nut removal prevention tool, and FIG. It is sectional drawing which shows the state which made the ring body free to rotate in the screwing direction and the opposite direction in the state which covered the member.

FIG. 8 is a front view of a spring member used for a protection device for a fastening portion according to a fourth embodiment.

FIG. 9 is a partial cross-sectional view of a ring body showing a cutout recess into which an outwardly bent projection of a spring member is engaged in the protection device for a fastening part according to the fourth embodiment.

FIG. 10 is a sectional view showing a protection device for a fastening portion according to a fifth embodiment.

FIG. 11 is a sectional view taken along line AA in FIG.
(A) shows a state when the outer ring body is rotated in the screwing direction, and (b) shows a state when the outer ring body is rotated in the opposite direction.

FIG. 12 shows a protection device for a fastening part according to a sixth embodiment,
(A) is a longitudinal sectional view, and (b) is a front sectional view showing a structure of a main part.

FIG. 13 is a front view of a retaining ring, which is a main component of the protection device for a fastening part according to the sixth embodiment.

FIG. 14 is a front view of a support which is a main part of a protection device for a fastening part according to a sixth embodiment.

FIG. 15 shows a protection device for a fastening part according to a seventh embodiment,
(A) is a longitudinal sectional view of the main part, and (b) is a front view of a spring member which is a main part member.

FIG. 16 is a sectional view showing another application example of the present invention.

[Explanation of symbols]

1, 2 Iron plate 3 Bolt member (screw member) 3a Screw part 4 Nut 5 Lock nut 6 Nut member 7, 7A, 7B, 7C, 7D, 7E Nut removal prevention tool 7b Ring body 7e Projection part 7p, 90a Cap part 8, 8A Spring member 7m Notch recess 7n Annular recess 8a Outwardly bent projection 7s Hole 9, 12, 12A Support 9a, 91, 94 Annular recess 10 Ended substantially circular spring body 10a Bend 10b Other end 11 Stop projection 7t Inward flange 12a Small diameter portion 12b Large diameter portion 12c Notch recess for locking 12m End 13 Retaining ring 13a Backward bent piece 14 Projection 51 Engagement projection 90, 93, 93A Outer ring body

Claims (7)

[Claims] 1. A protection device for a fastening portion, wherein a nut member is prevented from being removed at a fastening portion where the member to be fastened is fastened by a screw member and a nut member, wherein the member to be fastened is connected to the screw member. In the state of being fastened by the nut member, one or more coil-shaped spring members are contained on the inner surface side of the ring body by restricting the axial movement within a predetermined range and can be disengaged from the ends of the spring members. A nut removal prevention tool formed by providing an engaging portion to be engaged with the ring body is rotated in the forward direction while pressing against the end of the screw member, and the end of the spring member is engaged with the engaging portion. In the mating state, the screw member is advanced while being screwed into the screw portion of the screw member, and the ring member is further rotated in the forward direction while the ring member is in contact with the nut member or the member to be fastened, so that only the spring member More By screwing, the end of the spring member is disengaged from the engagement portion, so that the ring body is freely rotatable in both forward and reverse directions, so that the nut removal preventing device cannot be removed to protect the nut member. A protection device for a fastening portion, wherein the protection device is configured. 2. The protection device according to claim 1, wherein the ring body integrally includes a cylindrical cap portion that covers the nut member. 3. The engagement portion according to claim 1, wherein the engagement portion is formed by a projection that projects inward from an inner surface of the ring body and abuts on a rear end of the spring member. Protective device for fastening parts. 4. The engaging portion includes a notch recess formed on an inner surface of the ring body and an annular recess continuously located in front of the notch recess, and is formed at an end of the spring member. When the outward bent protrusion is engaged in the notched recess, the spring member rotates integrally with the ring body, and the outward bent protrusion of the spring member is located in the annular recess. The protection device for a fastening part according to claim 1, wherein the ring body is configured to be freely rotatable in both forward and reverse directions when the ring member is turned on. 5. A protection device for a fastening portion, wherein a nut member is prevented from being removed at a fastening portion where a member to be fastened is fastened by a screw member and a nut member, wherein the nut removal preventing tool is provided with an outer ring body. And a support that is screwed to the screw portion of the screw member and supports the outer ring body in a rotatable and axially immovable state, and between the outer ring body and the support body. And a one-way rotation transmitting means for transmitting rotation of the outer ring body only in the screwing direction to the support member and freely rotating the outer ring body in the opposite direction. 6. The protection device for a fastening part according to claim 5, wherein the outer ring body is integrally provided with a cylindrical cap part covering the nut member. 7. The supporting member is constituted by a coil-shaped spring member screwed into a screw portion of a screw member, and the outer ring is supported by the spring member in a rotatable and axially immovable state. The outer ring body is deformed radially outward, and the outer ring body is provided with an engagement projection which engages the rotation of the outer ring body only in the screwing direction with the end portion and transmits the rotation to the spring member, thereby rotating the outer ring body in one direction. The protection device for a fastening part according to claim 5 or 6, wherein the protection means comprises a transmission means.