JP2000120646A - Removal preventive cap for bolt and nut - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make difficult for a bolt and nut to be removed by mounting a cap on the tip of the bolt. SOLUTION: A large diameteric sleeve 4 is put on a nut 3 fastened to the tip of a bolt 2. A wrench is fitted on a ring member 7 put on a small diameteric sleeve 5, and the sleeve 5 is rotated together with the ring member 7 so that threads on the internal circumferential surface of the sleeve 5 are driven onto the tip of the bolt 2. At this time, the sleeve 5 is driven by a minor torque until a bottom flange 6 abuts to the top face of the nut 3 secured to the tip of the bolt 2, and when the flange 6 abuts to the nut 3, a torque is gradually increased to apply to a coupling member 8 installed between the flange 6 and the ring member 7. When the coupling member 8 is ruptured, the wrench is fitted on the ring member 7, and even if the ring member 7 is rotated in the direction of loosening, the ring member 7 remains idling with respect to the sleeve 5, so that it is not possible for the sleeve 5 to be rotated in the direction of loosening.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cap for preventing the removal of a bolt and a nut attached to the tip of a bolt in order to make it difficult to remove a bolt and a nut fixing a power transmission tower or the like. .

[0002]

2. Description of the Related Art An incident occurred in Sakaide City, Kagawa Prefecture, in which bolts and nuts fixing a power transmission tower were removed by someone and the power transmission tower was collapsed.

An object of the present invention is to provide a bolt / nut removal preventing cap which can make it difficult to remove the bolt / nut by mounting it on the tip of the bolt in order to prevent such incidents from reoccurring. It is.

[0004]

According to the present invention, there is provided a bolt and a bolt.
The nut removal prevention cap is a large-diameter cylindrical cylinder that is rotatably placed on the nut from the tip side of the bolt with a predetermined space around the nut that is tightened and fixed with the tip of the bolt protruding. A sleeve, a cylindrical small-diameter sleeve having a thread threaded to a bolt on an inner peripheral surface, a flange formed on an outer surface of a lower end of the small-diameter sleeve, and an outer periphery of the small-diameter sleeve, which is rotated with respect to the small-diameter sleeve. It is covered as possible, and the outer surface shape is made of the same ring member as the outer surface shape of the nut, and the flange portion and the ring member are joined between the opposing surfaces, and when the rotational torque of a certain degree or more is applied, it is broken. And a connecting member for releasing the connection between them is provided.

[0005] Since the bolts installed on the power transmission tower or the like are fastened so that the tips project from the nuts, the nuts fastened to the bolt tips are covered with a large-diameter sleeve, and are covered over the outer periphery of the small-diameter sleeve. A wrench is fitted on the outer surface of the ring member, and the small-diameter sleeve is rotated together with the ring member, so that the thread on the inner peripheral surface of the small-diameter sleeve is screwed into the tip of the bolt.

[0006] The small-diameter sleeve is screwed into the bolt tip with a relatively small rotating torque until the flange at the lower end contacts the outer surface of the nut fastened and fixed to the bolt tip. A large rotating torque is gradually applied to the connecting member provided between the flange portion and the ring member on the outer periphery of the small-diameter sleeve, and when the rotating torque of a certain level or more is applied, the connecting member is broken.

In this way, when the small-diameter sleeve is screwed into the end of the bolt to break the connecting member, the ring member can be moved relative to the small-diameter sleeve even if the wrench is fitted into the ring member and the ring member is rotated in the loosening direction. Since it runs idle, the small diameter sleeve cannot be rotated in the loosening direction.

In this state, the periphery of the nut is covered by the large-diameter sleeve, and the wrench cannot be fitted to the nut, so that the nut cannot be removed.

[0009]

FIG. 1 shows a fixing portion of a flange B of a power transmission tower A to which a cap 1 for preventing removal of bolts and nuts according to the present invention is attached.

The bolt 2 has a head and a shaft, and is inserted through the flange B such that the head is located on the lower surface side of the flange B of the power transmission tower A.

Two nuts 3 are fastened and fixed to the bolt 2, and the tips thereof protrude from the upper nut 3.

The bolt / nut removal prevention cap 1 according to the present invention comprises a large-diameter sleeve 4 which covers the two nuts 3 with a predetermined space, and a bolt 2 on the inner peripheral surface.
A cylindrical small-diameter sleeve 5 having a thread which is screwed into
Flange 6 formed on outer surface of lower end of small diameter sleeve 5
And a ring member 7 rotatably mounted on the outer periphery of the small diameter sleeve 5 with respect to the small diameter sleeve 5 and having the same outer surface shape as the outer surface shape of the nut 3.

The flange 6 and the ring member 7
A connecting member 8 which connects the two and breaks when a rotational torque of a certain degree or more is applied to release the connection between them.
Is provided. The connecting member 7 can be configured by inserting a pin that breaks with a certain force or more into a through hole formed in the ring member 7 and the flange portion 6.

The ring member 7 is rotatably connected to the small-diameter sleeve 5 by expanding the upper end edge of the small-diameter sleeve 5 outward.

The bolt / nut removal prevention cap 1 according to the present invention is made of metal and formed by forging or the like.

As shown in FIGS. 2 and 3, the small-diameter sleeve 5, the flange portion 6, and the large-diameter sleeve 4 may be integrally formed. Alternatively, the large-diameter sleeve 4 below the flange portion 6 may be formed as follows. As shown in FIGS. 6 and 7, they may be formed separately.

The method of using the bolt / nut removal preventing cap 1 according to the present invention is as follows.

First, a large-diameter sleeve 4 is put on a nut 3 fastened to the tip of a bolt 2. Then, a wrench is fitted on the outer surface of the ring member 7 covered on the outer periphery of the small-diameter sleeve 5, and the small-diameter sleeve 5 is rotated together with the ring member 7, and the thread on the inner peripheral surface of the small-diameter sleeve 5 is screwed into the tip of the bolt 2. Go out. At this time, the small-diameter sleeve 5 is screwed into the distal end of the bolt 2 with a relatively small rotating torque until the flange 6 at the lower end contacts the upper end surface of the nut 3 fastened to the distal end of the bolt 2. 6
When the nut contacts the nut 3, the flange 6 and the small-diameter sleeve 5
A large rotation torque is gradually applied to the connecting member 8 provided between the outer ring member 7 and the ring member 7. And the connecting member 8
When the wrench is broken, even if the wrench is fitted to the ring member 7 and the ring member 7 is rotated in the loosening direction, the ring member 7 idles with respect to the small-diameter sleeve 5, so that the small-diameter sleeve 5 is rotated in the loosening direction. Can not be done.

As described above, when the connecting member 8 is broken,
Since the ring member 7 idles and the nut 3 is also covered by the large-diameter sleeve 4, the wrench cannot be fitted to the nut 3 and the removal of the nut 3 can be prevented.

[0020]

As described above, the bolt according to the present invention
The nut removal prevention cap can be prevented from being removed by screwing into the tip of the bolt and breaking the connecting member.

Further, the outer shape of the ring member of the cap for preventing the removal of the bolt and nut is the same as the outer shape of the nut, so that a wrench having the same size as the tightening of the nut can be used. Good nature.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a use state of a bolt / nut removal prevention cap according to the present invention.

FIG. 2 is a perspective view showing an example of a bolt / nut removal prevention cap according to the present invention.

FIG. 3 is a longitudinal sectional view of the example of FIG. 2;

FIG. 4 is a longitudinal sectional view showing a state before a connecting member is broken in the example of FIG. 2;

FIG. 5 is a perspective view showing a state in which a connecting member is broken in the example of FIG. 2;

FIG. 6 is a perspective view showing another example of the bolt / nut removal prevention cap according to the present invention.

FIG. 7 is a longitudinal sectional view of the example of FIG. 6;

[Explanation of symbols]

 1 Cap to prevent removal of nuts and bolts 2 Bolt 3 Nut 4 Large diameter sleeve 5 Small diameter sleeve 6 Flange 7 Ring member 8 Connecting member

Claims (3)

[Claims] A cylindrical large-diameter sleeve rotatably mounted on the nut from the tip end side of the bolt with a predetermined space around a nut fixedly fastened with the tip end of the bolt protruding; A cylindrical small-diameter sleeve having a screw thread to be screwed into a bolt on an inner peripheral surface, a flange formed on an outer surface of a lower end of the small-diameter sleeve, and an outer periphery of the small-diameter sleeve rotatable with respect to the small-diameter sleeve. It is covered, and the outer surface shape is made of the same ring member as the outer surface shape of the nut. Between the opposed surfaces of the flange portion and the ring member, the two are joined, and when a rotation torque of a certain degree or more is applied, the two are broken and both are broken. A bolt for preventing removal of bolts and nuts, comprising a connecting member for releasing the connection between the bolt and the nut. 2. The bolt / nut removal prevention cap according to claim 1, wherein the flange portion and the small diameter sleeve are provided separately from the large diameter sleeve. 3. The bolt / nut removal prevention cap according to claim 1, wherein the flange portion and the small diameter sleeve are provided integrally with the large diameter sleeve.