JPH11303838A - Nut - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nut which is so hard that the removal of a nut by an outsider is nearly impossible. SOLUTION: This nut is composed of a nut body 1 whose outer periphery is circular and a split ring 2 made by a sheet spring and a ring shape groove 4 is formed on the center of a width direction on the outer periphery surface of the nut body 1 and big diameter parts 5, 6 whose diameter is bigger than the diameter of the groove 4 are formed on both sides of the groove 4 and an engaging hole 7 which can engage the engaged projection of the wrench for nut rotation is formed at the equal interval in the peripheral direction on the bottom of the groove 4 and the split ring 2 has an inner diameter inserted turnably in the groove 4 and its outer diameters 5, 6 are bigger than big diameter parts 5, 6. Thereby, even if it is grasped by a pipe wrench, the split ring 2 is only rotated and the nut body 1 is not rotated. Therefor, the outsider can not remove.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a nut. More specifically, the present invention relates to a nut that is almost impossible to remove by an outsider.

[0002]

2. Description of the Related Art Conventionally, various structures have been developed for preventing nuts from loosening, but all of them are devised so as not to loosen naturally even when vibrations or the like are applied. No attempt has been made to protect the nuts from being removed artificially, and double nuts or split pins are used only because they make the removal somewhat difficult. However, it is a well-known fact that both the double nut and the split pin can be removed using only commercially available tools with a little effort.

[0003]

In recent years, there has been an accident in which a tower of a high-voltage transmission line has been knocked down, but this has been carried out by removing a standard bolt and nut using a standard tool. . As a result, there was a significant effect.
It is not possible to deny the possibility that an accident that threatens the safety of people's lives by removing such nuts can occur not only in steel towers but also in many places such as nuclear power plants and viaducts.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a nut which makes it difficult for an outsider to remove the nut to a level that is almost impossible.

[0005]

According to a first aspect of the present invention, there is provided a nut comprising a nut body having a circular outer periphery and a split ring made of a leaf spring, and an annular groove formed in a central portion in a width direction on an outer peripheral surface of the nut body. Is formed on both sides of the groove, a large-diameter portion having a diameter larger than the diameter of the groove is formed, and at the bottom of the groove, an engagement hole for engaging an engagement protrusion of a nut rotating wrench is formed. The split ring is formed at equal intervals in the circumferential direction, the split ring has an inner diameter that can be fitted to the outer periphery of the groove, and the outer diameter is larger than the large diameter portion. A nut according to a second aspect is characterized in that, in the invention according to the first aspect, a ring end shape of the split ring is a male and female shape of a mountain shape and a valley shape. The nut according to claim 3 is characterized in that, in the invention according to claim 1, one of the large diameter portions of the nut body is formed on a guide slope whose diameter decreases from the inside to the outside. According to a fourth aspect of the present invention, in the first aspect of the present invention, the outer diameter of the groove of the nut body is a diameter that does not fit a commercially available standard nut wrench. According to a fifth aspect of the present invention, in the first aspect of the present invention, the circumferential pitch of the engaging holes of the nut body is a size that does not fit a commercially available standard nut wrench for rotating the nut. .

According to the first aspect of the present invention, it is extremely difficult to remove the split ring of the leaf spring without a special tool. Therefore, if an outsider attempts to remove the nut, the outside circumference is grasped with a pipe wrench. The nut can not be rotated because the split ring rotates in the groove. Further, since the large diameter portion of the nut is smaller in diameter than the split ring, the nut body cannot be directly gripped with a pipe wrench. Therefore, according to the nut of the present invention, it is extremely difficult for an outsider to remove the nut, and it is almost impossible for the outsider to remove the nut while watching the surroundings. According to the second aspect of the present invention, since the end of the split ring has a unique male and female shape, it cannot be removed from the nut body unless a dedicated tool is used. For this reason, removal of the nut by an outsider can be made extremely difficult. According to the third aspect of the present invention, since the guide slope is formed on one of the large-diameter portions, the work of fitting the split ring into the groove can be easily performed.
According to the invention of claim 4, even if the split ring is removed, the nut body cannot be rotated because the outer diameter of the groove does not match the commercially available tool. Therefore, the effect of preventing the nut from being removed by an outsider is high. According to the invention of claim 5,
Even if the split ring is removed, the nut body cannot be rotated because the engaging hole does not match with a commercially available tool, and thus the effect of preventing the nut from being removed by an outsider is enhanced.

[0007]

Next, embodiments of the present invention will be described with reference to the drawings. 1 is a perspective view of a nut A according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of a nut body and a split ring, FIG. 3 is a partially sectional front view of the nut A, and FIG. is there.

In FIGS. 1 and 2, 1 is a nut body and 2 is a split ring. The nut body 1 has a cylindrical shape with a short axial length, and its outer periphery is circular. A female screw 3 is cut at the axial center of the nut body 1. As shown in FIGS. 2 and 3, an annular groove 4 is formed at the center in the width direction on the outer peripheral surface of the nut body 1, and large-diameter portions 5 and 6 are formed on both sides of the groove 4. I have. And, a portion 5 having a larger diameter than the outer diameter D1 of the groove 4,
The outer diameter D2 of No. 6 is slightly larger.

At the bottom of the groove 4, engagement holes 7 are formed at regular intervals in the circumferential direction. In the present embodiment, the circumferential pitch P of the engaging holes 7 is 72 degrees, and the pitch P is 5 degrees.
Individually formed. In the case of a normal nut, six wrench portions are provided at 60-degree intervals so that a standard wrench does not fit. Note that the number may be any number outside the standard, and therefore may be seven or more. The number of the engagement holes 7 may be four or less, or one. In the case of even numbers or more, it is only necessary to shift from the diagonal line. Similarly, the outer diameter D1 of the groove 4 is preferably set to a size that does not fit a standard wrench. The side wall between the groove 4 and the large diameter portions 5 and 6 rises at a right angle. One large-diameter portion 5 decreases in diameter from the inside to the outside, and is formed on the guide slope 5a.

The split ring 2 is made of a leaf spring, and can be bent by the elasticity of the split ring 2 so as to get over one of the large-diameter portions 5 and easily fit into the groove 4. Then, in the fitted state, the split ring 2 is reduced in diameter by its own elasticity and tightens the groove 4. When the split ring 2 is rotated by a tool or the like, it rotates around the groove 4, but does not rotate around with a light force. In addition, there is no possibility of jumping over the large diameter portions 5 and 6 to the outside.

With the split ring 2 fitted in the groove 4 as described above, the outer diameter D3 of the split ring 2 is slightly larger than the outer diameter D2 of the large diameter portions 5 and 6, and even if the split ring 2 is gripped with a pipe wrench or the like. , The outer circumference of the split ring 2 can be grasped,
The nut body 1 cannot be grasped directly. Therefore, even if an outsider uses a commercially available pipe wrench, the nut body 1 cannot be rotated only by rotating the split ring 2.

The ring end shape of the split ring 2 is a chevron 2
a and a valley 2b. The number of the ridges 2a and the valleys 2b may be one at a time, or may be two or three knurls. It is preferable that no gap is formed between both ends. In this case, it is difficult to insert the tip of a screwdriver or the like to pry off the end, and without the dedicated tool, the split ring 2 cannot be easily removed.

Since the insider needs to be able to freely remove the nut A for maintenance and inspection, it is necessary to use a dedicated split ring removing tool and a nut rotating wrench B. The wrench B includes a handle 11, a curved portion 12, and an engagement protrusion 1.
3, and the shape is almost the same as that of a standard commercial wrench, but the inner peripheral curvature d of the curved portion 12 has a peculiar size corresponding to the outer periphery of the groove 4. Therefore, a standard wrench that can be easily obtained by an outsider cannot turn the nut body 1 of the present invention, but only an insider having the special wrench B in FIG. 4 can freely tighten the nut body 1 of the present invention. It can be loosened or loosened.

Next, advantages of the nut A of the present embodiment will be described. Since it is extremely difficult to remove the split ring 2 of the leaf spring without a special tool, if an outsider attempts to remove the nut A, he or she can only turn the outer periphery by gripping the outer circumference with a pipe wrench. Since the nut 2 rotates in the groove 4, the nut A cannot be rotated. Further, since the large diameter portion of the nut A is smaller in diameter than the split ring 2, the nut body 1 cannot be directly gripped with a pipe wrench. Therefore, it is extremely difficult for an outsider to remove the nut A, and it is almost impossible for the outsider to remove the nut A while watching the surroundings. Since the end of the split ring 2 has a unique male and female shape, it cannot be removed from the nut body 1 unless a dedicated tool is used. For this reason, removal of the nut A by an outsider can be made extremely difficult. Since the guide slope 5a is formed on one of the large diameter portions 5, the work of fitting the split ring 2 into the groove 4 can be easily performed.
However, since there is no slope between the groove 4 and the large-diameter portions 5 and 6 and there is a groove side wall which rises at a right angle, it is difficult to remove the split ring 2, so that the effect of preventing removal is high. Even if the split ring 2 is removed, the nut body 1 cannot be rotated because the outer diameter of the groove 4 does not match a commercially available tool. Therefore, the effect of preventing the nut A from being removed by an outsider is high. Even if the split ring 2 is removed, the nut body 1 cannot be rotated because the engaging hole 7 does not match with a commercially available tool, and thus the effect of preventing the nut A from being removed by an outsider is enhanced.

[0015]

According to the first aspect of the present invention, it is extremely difficult to remove the nut by an outsider since the nut body cannot be directly grasped with a pipe wrench. It is almost impossible to remove it. According to the invention of claim 2, since the split ring cannot be removed from the nut body, it is extremely difficult for an outsider to remove the nut. According to the invention of claim 3,
Since the guide slope is formed on one of the large-diameter portions, the work of fitting the split ring into the groove can be easily performed. According to the invention of claim 4, since the outer diameter of the groove does not match that of a commercially available tool, the nut body cannot be rotated. Therefore, the nut removal effect by an outsider is high. According to the invention of claim 5,
Since the engaging hole does not match with a commercially available tool, the nut body cannot be rotated, so that the effect of preventing the nut from being removed by an outsider is enhanced.

[Brief description of the drawings]

FIG. 1 is a perspective view of a nut A according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a nut body and a split ring.

FIG. 3 is a partially sectional front view of a nut A;

FIG. 4 is a plan view of a dedicated wrench.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Nut body 2 Split ring 4 Groove 5, 6 Large diameter part 7 Engagement hole

Claims (5)

[Claims] An annular groove is formed at the center in the width direction on the outer peripheral surface of the nut body, and grooves are formed on both sides of the groove. A large diameter portion having a diameter larger than the diameter of the nut is formed, and at the bottom of the groove, engagement holes for engaging the engagement protrusions of the nut rotating wrench are formed at equal intervals in the circumferential direction, The nut according to claim 1, wherein the split ring has an inner diameter that can be fitted to an outer periphery of the groove, and an outer diameter thereof is larger than the large diameter portion. 2. The nut according to claim 1, wherein the ring end of the split ring has a male and female shape of a mountain shape and a valley shape. 3. The nut according to claim 1, wherein one large-diameter portion of the nut body is formed on a guide slope whose diameter decreases from the inside to the outside. 4. The nut according to claim 1, wherein the outer diameter of the groove of the nut body does not match a commercially available standard nut wrench. 5. The nut according to claim 1, wherein the circumferential pitch of the engaging holes of the nut body is a size that does not match a commercially available standard-rotation nut wrench.