JP3103067B2 - Nut removal prevention structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nut removal prevention structure that disables effective rotation of a nut after tightening and prohibits disassembly and disengagement of an object to be fixed.

[0002]

2. Description of the Related Art There has been reported an unrest situation in which an installation bolt of a power transmission tower or a rail fixing bolt of a shinkansen is removed by a person other than an authorized administrator. This occurs because in the conventional bolted joint structure, the nut fitted to the head of the bolt or the shaft of the bolt is unprotected and exposed, making it easier for an outsider to attach the bolt or nut. Because it can be turned.

[0003]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a nut removal preventing structure in which an effective rotation operation of a nut cannot be performed after the nut has been tightened with a certain force or more.

[0004]

Means for Solving the Problems Hereinafter, a description will be given using reference numerals in the accompanying drawings. In the nut removal prevention structure according to the first aspect of the present invention, the nut 2 into which the bolt 1 penetrates is fitted to the outer case 3 And the inner fastening part 4 constitutes a double structure, and the shaft part 1b of the bolt 1 projects outside.
An inner peripheral flange 3b is formed at the opening on the distal end side of the case 3,
The flange 3b abuts on the end face 4e of the tip of the inner fastening part 4.
Then, fit the outer case 3 to the inner fastening part 4
The outer case 3 does not come off from the inner fastening part 4
Assembled as shown in FIG.
When the nut 2 is tightened with a certain force or more, a part 4b of the inner tightening part 4 is broken, and the outer case 3 is formed to idle with respect to the remaining part 4a of the inner tightening part 4.

[0005] In this nut removal preventing structure, when the nut 2 is tightened with a certain force or more, the inner tightening part 4 is tightened.
Is cut off from the remaining portion 4a, so that the outer case 3 shifts to the idling state. Therefore, after this, no matter how much you try to turn the nut 2 in the direction to loosen the nut 2 by fitting a rotary operation tool such as a wrench or torque wrench into the outer case,
The rotation torque is not transmitted from the outer case 3 to the remaining portion 4a of the inner fastening part 4, and the initial threaded state of the remaining part 4a of the inner fastening part 4 and the shaft 1b of the bolt 1 is accurately maintained. You.

According to the second aspect of the present invention, the nut 2 into which the bolt 1 penetrates is formed in a double structure by the outer case 3 and the inner fastening part 4, and the shaft 1b of the bolt 1 is provided.
The inner peripheral flange 3b is provided at the tip end side opening of the outer case 3 from which
And forming the inner peripheral flange 3b at the tip of the inner fastening part 4.
A part for fastening the outer case 3 to the inside by abutting the end face 4e.
4 and the outer case 3 is the inner fastening part 4
Assembly not to Luo pulled out, when tightening the nut 2 with a constant force or more to the inner clamping part 4 is fitted a shaft portion 1b of the bolt, the outer casing 3 clamping inner part 4b of the inner clamping part 4 with broken In the nut removal prevention structure formed so as to rotate with respect to the remaining portion 4a of the component 4, a part 4b of the broken inner tightening component is fitted to the outer case 3 so as to be relatively non-rotatable while the inner tightening component 4 is fitted. Of the inner fastening part to be broken and the remaining part 4a of the inner fastening part are connected to each other via the weak part 4c, and the weak part 4c is formed. To break.

In this nut removal preventing structure, when the nut 2 is tightened with a certain force or more, the inner tightening part 4 is tightened.
Is cut off from the remaining portion 4a in the fragile portion 4c, so that the outer case 3 shifts to the idling state. Therefore, after that, even if a rotary operation tool such as a wrench or a torque wrench is fitted into the outer case and the nut 2 is turned in a loosening direction, the outer case 3 and the part 4b of the broken inner fastening part 4 are integrated. , And the rotational torque is not transmitted from the outer case 3 to the remaining portion 4 a of the inner fastening part 4. Therefore, the initial threaded state of the remaining portion 4a of the inner fastening part 4 and the shaft portion 1b of the bolt 1 is firmly maintained.

[0008]

In the embodiment shown in FIG. 1, the shaft portion 1b of the bolt 1 is inserted into the through hole 8 of the fixing object 6 and the through hole 9 of the fixing object 7, and the fixing objects 6, Reference numeral 7 denotes a tightening joint between the tightening nut 5 screwed to the shaft portion 1b of the bolt 1 and the head 1a of the bolt 1. The nut removal preventing structure of the present invention is applied to a nut screwed next to the tightening nut 5. The outer peripheral shape of the broken part 4b of the inner fastening part 4 and the inner peripheral shape of the corresponding part 3d of the outer case 3 into which the part 4b is fitted are regular hexagons.
The outer peripheral shape of the remaining portion 4a of the inner fastening portion 4 and the inner peripheral shape of the corresponding portion 3c of the outer case 3 into which the remaining portion 4a is fitted are circular. An annular groove having a V-shaped cross section is provided between a part 4b and the remaining part 4a of the inner fastening part 4 to be broken, thereby forming a weak part 4c. When a rotational torque equal to or greater than a certain value is applied, the threading force acts on the fragile portion 4c in a concentrated manner, so that the inner fastening part 4 is broken and divided at the fragile portion 4c.

In order to fulfill the function as a nut member, the inner fastening part 4 is formed with a thread on the inner peripheral surface. The inner fastening part 4 and the outer case 3 are fitted coaxially, and the outer case 3 is assembled so as not to come off from the inner fastening part 4 in order to fulfill the function as a case. In the embodiment of FIG. 1, the inner peripheral edge 3 a of the proximal opening of the outer case 3 is pressed to be engaged with the outer peripheral step 4 d at the proximal end of the inner fastening part 4, while the distal end of the outer case 3 is engaged. By bringing the inner peripheral flange portion 3b of the opening into contact with the end face 4e of the distal end portion of the inner fastening component 4, the outer case 3 is prevented from coming off from the inner fastening component 4.

In the embodiment shown in FIG.
Is inserted through the through hole 8 of the fixing object 6, the through hole 9 of the fixing object 7, and the through hole 11 of the washer 10, and the fixing objects 6 and 7 are screwed into the shaft 1 b of the bolt 1. The fastening nut 2 and the head 1 a of the bolt 1 are fastened and joined via a washer 10. The nut removal preventing structure of the present invention is applied to the tightening nut 2 itself. The outer peripheral shape of the broken part 4b of the inner fastening part 4 and the inner peripheral shape of the corresponding part 3d of the outer case 3 into which the part 4b is fitted are regular hexagons. The outer peripheral shape of the remaining portion 4a of the inner fastening portion 4 and the inner peripheral shape of the corresponding portion 3c of the outer case 3 into which the remaining portion 4a is fitted are circular. An annular groove having a V-shaped cross section is provided between a part 4b and the remaining part 4a of the inner fastening part 4 to be broken, thereby forming a weak part 4c. When a rotational torque equal to or greater than a certain value is applied, the threading force acts on the fragile portion 4c in a concentrated manner, so that the inner fastening part 4 is broken and divided at the fragile portion 4c.

In order to fulfill the function as a nut member, the inner tightening part 4 is formed with a thread on the inner peripheral surface. The inner fastening part 4 and the outer case 3 are fitted coaxially, and the outer case 3 is assembled so as not to come off from the inner fastening part 4 in order to fulfill the function as a case. In the embodiment of FIG. 3, the inner peripheral edge 3 a of the proximal end opening of the outer case 3 is pressed to engage with the outer peripheral step 4 d at the proximal end of the inner fastening part 4, while the distal end of the outer case 3 is engaged. By bringing the inner peripheral flange portion 3b of the opening into contact with the end face 4e of the distal end portion of the inner fastening component 4, the outer case 3 is prevented from coming off from the inner fastening component 4. As the washer 10, a spring washer can be used in addition to the normal flat washer,
Further, the washer can be omitted.

In the embodiment shown in FIG.
Is inserted through the through hole 8 of the fixing object 6, the through hole 9 of the fixing object 7, and the through hole 11 of the washer 10, and the fixing objects 6 and 7 are screwed into the shaft 1 b of the bolt 1. The fastening nut 2 and the head 1 a of the bolt 1 are fastened and joined via a washer 10. The nut removal preventing structure of the present invention is applied to the tightening nut 2 itself. The outer peripheral shape of the broken part 4b of the inner fastening part 4 and the inner peripheral shape of the corresponding part 3d of the outer case 3 into which the part 4b is fitted are regular hexagons. The outer peripheral shape of the remaining portion 4a of the inner fastening portion 4 and the inner peripheral shape of the corresponding portion 3c of the outer case 3 into which the remaining portion 4a is fitted are circular. An annular groove having a V-shaped cross section is provided between a part 4b and the remaining part 4a of the inner fastening part 4 to be broken, thereby forming a weak part 4c. When a rotational torque equal to or greater than a certain value is applied, the threading force acts on the fragile portion 4c in a concentrated manner, so that the inner fastening part 4 is broken and divided at the fragile portion 4c.

In order to fulfill the function as a nut member, the inner tightening part 4 is formed with a thread on the inner peripheral surface. The inner fastening part 4 and the outer case 3 are fitted coaxially, and the outer case 3 is assembled so as not to come off from the inner fastening part 4 in order to fulfill the function as a case. In the embodiment of FIG. 5, a C-shaped retaining ring 3f fitted in an annular groove 3e in the inner peripheral portion of the proximal end opening of the outer case 3 is connected to the outer peripheral step portion 4 of the proximal end portion of the inner fastening component 4.
d, while the inner peripheral flange 3b of the opening on the distal end side of the outer case 3 is brought into contact with the end face 4e of the distal end of the inner tightening part 4, so that the outer case 3 can be removed from the inner tightening part 4. Has been blocked. As the washer 10, a spring washer may be used in addition to a normal flat washer, and the washer may be omitted.

In the embodiment shown in FIG.
Is inserted through the through hole 8 of the fixing object 6, the through hole 9 of the fixing object 7, and the through hole 11 of the washer 10.
7 is a fastening nut 2 screwed to the shaft 1b of the bolt 1.
And the head 1 a of the bolt 1 are fastened and joined via a washer 10. The nut removal preventing structure of the present invention is applied to the tightening nut 2 itself. The outer peripheral shape of the broken part 4b of the inner fastening part 4 and the inner peripheral shape of the corresponding part 3d of the outer case 3 into which the part 4b is fitted are regular hexagons. The outer peripheral shape of the remaining portion 4a of the inner fastening portion 4 and the inner peripheral shape of the corresponding portion 3c of the outer case 3 into which the remaining portion 4a is fitted are circular. An annular groove having a V-shaped cross section is provided between a part 4b and the remaining part 4a of the inner fastening part 4 to be broken, thereby forming a weak part 4c. When a rotational torque equal to or greater than a certain value is applied, the threading force acts on the fragile portion 4c in a concentrated manner, so that the inner fastening part 4 is broken and divided at the fragile portion 4c.

In order to fulfill the function as a nut member, the inner fastening part 4 is formed with a thread on the inner peripheral surface. The inner fastening part 4 and the outer case 3 are fitted coaxially, and the outer case 3 is assembled so as not to come off from the inner fastening part 4 in order to fulfill the function as a case. In the embodiment shown in FIG. 7, the inner peripheral edge 3 a of the proximal opening of the outer case 3 is pressed to be engaged with the outer peripheral step 4 d at the proximal end of the inner fastening part 4, while the distal end of the outer case 3 is engaged. The C-shaped retaining ring 3h fitted in the annular groove 3g on the inner peripheral portion of the opening is brought into contact with the end face 4e of the tip portion of the inner fastening component 4, thereby preventing the outer case 3 from being pulled out of the inner fastening component 4. ing.
As the washer 10, a spring washer may be used in addition to a normal flat washer, and the washer may be omitted.

In the embodiment shown in FIG.
Is inserted through the through hole 8 of the fixing object 6, the through hole 9 of the fixing object 7, and the through hole 11 of the washer 10, and the fixing objects 6 and 7 are screwed into the shaft 1 b of the bolt 1. The fastening nut 2 and the head 1 a of the bolt 1 are fastened and joined via a washer 10. The nut removal preventing structure of the present invention is applied to the tightening nut 2 itself. A part 4b of the inner fastening portion 4 to be broken is constituted by a pin-like body which is fitted and fixed in a receiving hole 4f of an end face 4e of the tip of the remaining portion 4a.
Is fitted into the through hole 3i of the inner peripheral flange portion 3b at the opening on the distal end side. The outer peripheral shape of the remaining portion 4a of the inner fastening portion 4 and the inner peripheral shape of the corresponding portion 3c of the outer case 3 into which the remaining portion 4a is fitted are circular. An annular groove having a V-shaped cross section is provided at an intermediate portion of the broken part 4b of the inner fastening part 4 formed of a pin-like body, thereby forming a fragile portion 4c. When a rotational torque equal to or more than a certain value is applied, the threading force acts on the fragile portion 4c in a concentrated manner, so that the pin-shaped body is broken and divided at the portion. A plurality of the pin-shaped members may be provided, or may be provided not on the end face but on the side face of the inner fastening part 4, and further, a plurality of pin-shaped bodies may be provided on the end face or side face. Instead of fitting a separate pin-shaped body, the part 4b to be broken may be integrally formed as a projection from the base material of the inner fastening member 4.

In order to fulfill the function as a nut member, the inner fastening part 4 is formed with a thread on the inner peripheral surface. The inner fastening part 4 and the outer case 3 are fitted coaxially, and the outer case 3 is assembled so as not to come off from the inner fastening part 4 in order to fulfill the function as a case. In the embodiment of FIG. 9, the inner peripheral edge 3 a of the proximal opening of the outer case 3 is pressed to be engaged with the outer peripheral step 4 d at the proximal end of the inner fastening part 4, while the distal end of the outer case 3 is engaged. By bringing the inner peripheral flange 3b of the opening into contact with the end face 4g of the tip of the remaining portion 4a of the inner tightening part 4, the outer case 3 is prevented from coming off from the inner tightening part 4. As the washer 10, a spring washer may be used in addition to a normal flat washer, and the washer may be omitted.

In each of the above-described embodiments, the cross-sectional shape of the outer case 3 and a part of the inner fastening part 4 to be broken is a regular hexagonal shape. This is because torque is transmitted from the outer case 3 to the portion 4b. Any shape is acceptable,
Another cross-sectional shape such as a square or an ellipse can be appropriately selected.

[0019]

As described above, in the nut removal preventing structure according to the first aspect of the present invention, the part 4b of the inner tightening part 4 is separated from the remaining part 4a by tightening the nut 2 with a certain force or more. even if Mawaso in the direction of loosening the nuts 2, only a portion 4b and the outer casing 3 of the inner clamping part 4 is broken idles, the inner
The outer cable assembled so that it does not come off from the fastening part 4
The inner peripheral flange 3b of the screw 3 is the end face of the tip of the inner fastening part 4.
4e abuts on the inner fastening part 4
Since the tool cannot be hung, an effective rotation operation of the remaining portion 4a of the inner fastening part 4 is impossible. Therefore, the remaining portion 4a of the inner fastening part 4 is left at the initial screwing position with the shaft portion 1b of the bolt 1, and the nut 2 is properly protected from being unremoved.

In the nut removal preventing structure according to the second aspect of the present invention, when the nut 2 is tightened with a certain force or more, a part 4b of the inner tightening part 4 is cut off from the remaining part 4a in the weak part 4c, and the outer case 3 Is shifted to the idling state, so that the rotational torque is not transmitted from the outer case 3 to the remaining portion 4a of the inner fastening component 4, and the effective rotation operation of the remaining portion 4a of the inner fastening component 4 is impossible. It is. For this reason, the remaining portion 4a of the inner fastening part 4 is firmly maintained in the initial screwed state with the shaft portion 1b of the bolt 1, and the nut 2 is properly protected from unauthorized removal.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a bolt-nut joint to which a nut removal prevention structure according to an embodiment of the present invention is applied.

FIG. 2 is a right side view of the bolt / nut joint of FIG.

FIG. 3 is a longitudinal sectional view of a bolt / nut joint to which a nut removal prevention structure according to another embodiment of the present invention is applied.

FIG. 4 is a right side view of the bolt / nut joint shown in FIG. 3;

FIG. 5 is a longitudinal sectional view of a bolt / nut joint to which a nut removal prevention structure according to another embodiment of the present invention is applied.

FIG. 6 is a right side view of the bolt / nut joint of FIG. 5;

FIG. 7 is a longitudinal sectional view of a bolt / nut joint to which a nut removal prevention structure according to still another embodiment of the present invention is applied.

8 is a right side view of the bolt / nut joint shown in FIG. 7;

FIG. 9 is a longitudinal sectional view of a bolt / nut joint to which a nut removal prevention structure according to still another embodiment of the present invention is applied.

FIG. 10 is a right side view of the bolt / nut joint of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bolt 2 Nut 3 Nut outer case 4 Nut inner tightening part 5 Nut 6 Fixing object 7 Fixing object 8 Through hole 9 Through hole 10 Washer

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16B 41/00 F16B 31/02

Claims (2)

(57) [Claims] 1. A nut through which a bolt is inserted and fitted,
Opening on the tip side of the outer case, which is formed into a double structure by the outer case and the inner fastening parts, and from which the shaft of the bolt projects.
The inner peripheral flange is formed on the inner peripheral flange, and the inner peripheral flange is
A part for fastening the outer case to the inner side by abutting the end surface of the tip
And the outer case comes out of the inner fastening parts.
When assembling so that the bolt of the bolt is inserted into the inner tightening part and the nut is tightened with a certain force or more, a part of the inner tightening part breaks and the outer case idles against the remaining part of the inner tightening part Nut removal prevention structure formed as above. 2. A nut through which a bolt is inserted and fitted,
Opening on the tip side of the outer case, which is formed into a double structure by the outer case and the inner fastening parts, and from which the shaft of the bolt projects.
The inner peripheral flange is formed on the inner peripheral flange, and the inner peripheral flange is
A part for fastening the outer case to the inner side by abutting the end surface of the tip
And the outer case comes out of the inner fastening parts.
When assembling so that the bolt of the bolt is inserted into the inner tightening part and the nut is tightened with a certain force or more, a part of the inner tightening part breaks and the outer case idles against the remaining part of the inner tightening part In the nut removal prevention structure formed as described above, a part of the inner tightening part to be broken is fitted into the outer case so as not to rotate relative thereto, while a remaining part of the inner tightening part is fitted to the outer case so as to rotate relative to the outer case. A nut removal prevention structure, wherein a part of an inner fastening portion to be broken and joined and a remaining portion of the inner fastening component are continuously connected via a fragile portion to break at the fragile portion.