JP2000046027A - Bolt and nut having shape difficult to fasten and loosen without use of proprietary tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bolt and nut which can be handled for fastening and loosening by only such a restricted operator as possessing a proprietary tool by introducing shapes of bolt and nut which do not allow use of any conventional tool. SOLUTION: The fastening and loosening parts 1 and 6 of a bolt and nut are given a circular section when cut perpendicularly to the center line of their threads, and the cut is shaped so that the section area decreases as going in a certain direction along the center line of the threads. Dimples in hemi-spherical form are provided in 3, 5, 7 or 9 places in accordance with the size of the bolt and nut from the periphery toward the thread center line of their fastening and loosening part 1 and 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bolt and a nut which are one of means for firmly connecting separately existing objects to each other and connecting them as if they were an integral structure.

[0002]

2. Description of the Related Art Currently used bolts and nuts are often tightened and loosened in a cross section cut at right angles to a screw center line, and are generally square, regular hexagonal, regular octagonal. Most of them are regular hexagons. An existing tool, for example, pliers, pliers, a spanner, a monkey spanner, a wrench, etc., can be easily tightened and loosened on the opposite parallel surfaces of the polygon.

[0003]

[0009] The round surface of the bolt and nut according to the present invention, which has been tightened and loosened, has a circular shape, so that the parallel surface is eliminated and a tool for working using the parallel surface can be used. Disappears.

[0004] Next, since the area of the cut surface is made to decrease as the cutting is performed in a certain direction along the center line of the screw, the appearance is not a columnar shape but a frustoconical or hemispherical shape. As a result, the shape becomes not parallel to the screw center line, but becomes inclined. The greater the inclination of the existing tool, the more the existing tool tries to grip, and the more the gripping force is applied, the more the sliding force along the slope is generated, and the more difficult it is to grip.

[0005] By quenching the surface of the tightening and loosening portions of the bolts and nuts according to the present invention, the sliding effect can be further enhanced, and the tightening and loosening work with existing tools becomes difficult.

According to the present invention, a hemispherical recess is formed at right angles from the outer peripheral direction of the bolt and nut to the center line of the screw from the outer circumferential direction of the loosened portion to the size of the bolt and cut in accordance with the size of the bolt and cut. Odd-numbered places are provided to use these parts to tighten and loosen bolts and nuts.

[0007] The purpose of forming the hemispherical recess is to prevent the use of existing tools by not forming protrusions on the outer periphery.

The purpose of making the number of the hemispherical dents odd is that if there is a dent at a position symmetrical with respect to the center line of the screw, it becomes easy to make a hand-made tightening and loosening tool. Even when used, it is slippery and hard to transmit power.

[0009]

As the bolts and nuts according to the present invention cannot be used with existing tools, anyone cannot easily tighten or loosen them unless special tools are used. Since this increases inconvenience, it seems at first glance that this is the opposite direction from the line of inventions and ideas pursuing convenience and simplicity. However, by restricting the use of bolts and nuts according to the present invention except for a limited number of persons with special tools, it is possible to secure the joints between rails and railroad ties, railway towers and bridges, etc. The probability of mischievous mischief by the general outsider, who is not directly related, can be kept low, so that even if there are some inconveniences and restrictions, it will be useful for the safety and security of many people's lives. I think that it may be possible to partially contaminate the last seat of the invention.

[Brief description of the drawings]

Fig. 1 shows a bolt with a frusto-conical shape with tightened and loosened parts. Fig. 2 shows a nut that has been tightened and loosened into a truncated cone. FIG.
Is a bolt that has been tightened and loosened. Fig. 4 shows a nut with a hemispherical tightened and loosened part. 1 Tighten and loosen bolts. 2 Hemispherical dent for tightening and loosening. 3 Male thread. 4 Female thread part. 5 Hemispherical dent for tightening and loosening. 6 Tightening and loosening nuts 7 Tightening and loosening bolts 8 Semi-spherical hollow for tightening and loosening. 9 Male thread. 10 Female thread part. 11 Hemispherical dent for tightening and loosening. 12 Tighten and loosen nuts.

Claims (2)

[Claims] 1. A bolt and a nut are tightened and loosened so that a cross-sectional shape obtained by cutting at right angles to a center line of a screw is circular, and a cut is formed in a predetermined direction along the center line of the screw. The shape is such that the cross-sectional area decreases as it proceeds. 2. A hemispherical recess from the outer periphery toward the screw center line of the tightening and loosening of the bolts and nuts is adjusted to 3, 5, 7, 9 according to the size of the bolts and nuts. A shape that can be made in several places, tightened, and loosened.