JPS61244912A - Locking device for nut - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an improvement in a locking device for a nut that is screwed onto a bolt to tighten and fix a member to be fastened.

Conventional technology Consists of a pair of nuts, one of which is provided with a protrusion that surrounds a screw hole and has a tapered outer circumferential surface with a truncated conical shape, and the other nut has an inner circumferential surface with a tapered truncated conical surface. A nut loosening device is known, in which a recess is formed on a tapered surface of a shape and is fitted into the protrusion, and either the protrusion or the recess is eccentric with respect to the axis of the screw hole. (Refer to Utility Model Publication No. 50-36123).

The above-mentioned nut loosening device is used to tighten the nut by applying force to the screw fitting part in a direction perpendicular to the axis line by imitation of the truncated conical tapered surfaces of the protrusion and recess that fit eccentrically with respect to the screw hole. Pressure, or shearing force, is applied and exhibits an excellent locking effect.

FIG. 3 shows the above-mentioned nut locking device in use, and consists of a pair of nuts 11, 12 which are screwed into the threaded portion 22 of the bolt 21. Natsu 11 on the other hand
has a protrusion 13 that surrounds the screw hole 15 and is formed into a tapered surface 14 having a truncated conical outer peripheral surface;
The center line A of the screw hole 15 is a small distance e from the axis 0 of the screw hole 15.
Only eccentric. The other nut 12 has a recess 16 into which the protrusion 13 of the nut 11 fits, and the inner circumferential surface of the recess 16 is also formed into a truncated conical tapered surface 17 like the protrusion 13. The tapered surface 17 is provided concentrically with the axis of the screw hole 18. The inclination angles of the tapered surfaces 14 and 17 are equal so that the tapered surface 14 of the protrusion 13 and the tapered surface 17 of the recessed portion 16 completely match and fit together.

Problems to be Solved by the Invention By the way, if the nuts 11 and 12 are hot-dip galvanized, for example, the plating film will be thick and uneven, so the dimensions of the screw holes 15 and 18 will be too large for the bolts 21 to be screwed together. It is larger overall than the threaded part 22, and when the nut 11.12 is screwed into the threaded part 22, a large amount 23 is formed between the threaded hole 15.18 and the threaded part 22, so that the protruding part After tightening and fixing the member 20 to be fastened with the nut 11 equipped with the nut 13, the recess 16 is fitted into the protrusion 13 and the nut 12 is tightened.
When tightened, the nut 12 tilts with respect to the axis O of the threaded portion 22, as shown in FIG.
comes into contact only with the upper edge 13a of the protrusion 13. As a result, the shear force P due to the wedge effect of both tapered surfaces 14.17
The stress is concentrated on the upper edge 13a of the protrusion 13, and the stress concentration causes deformation of the thread 15a near the opening at the tip of the protrusion 13 and the thread 22a of the bolt 21 screwed thereon. . If the thread 15a of the protrusion 13 and the thread 22a screwed thereon are partially deformed in this way, not only will a good locking effect not be obtained, but the nut 11 and bolt 21 will not be able to be reused. was there.

Incidentally, a similar problem occurs when the nuts 11 and 12 are reversed and the member 20 to be fastened is tightened with the nut 12 provided with the recess 16, and the nut 11 provided with the protrusion 13 is used as a loosening means. In addition, the above-mentioned problem is
1.12 occurs not only when hot-dip galvanizing is applied, but also when there is a large dimensional difference due to tolerance between the threaded hole of the nut and the threaded portion of the bolt.

Means for Solving the Problems The present invention has been made to solve the above-mentioned conventional drawbacks, and it is a simple method of making the angle of inclination of the tapered surface of the protrusion larger than the angle of inclination of the tapered surface of the recess. To provide an improved nut loosening device which can obtain an excellent loosening effect even when the threaded portion of the bolt has a large amount by technical means.

Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings. As shown in FIGS. 1 and 2, the device of the present invention includes a nut 1 having a protrusion 3 surrounding a screw hole 5 and having a tapered surface 4 having a truncated conical outer peripheral surface; 3, the recess 6 is formed into a tapered surface 7 having a truncated conical inner peripheral surface.
It is the same as the conventional device in that the center line A of the tapered surface 4 of the protrusion 3 is eccentric by a slight distance e with respect to the axis O of the screw hole 5, but the protrusion 3 The inclination angle α of the tapered surface 4 of the recess 6 is approximately 10 degrees, whereas the inclination angle β of the tapered surface 7 of the recess 6 is designed to be approximately 7 degrees, and the inclination angle α is larger than β. It's different.

With this configuration, when the member 20 to be fastened is tightened and fixed with the nut 1 having the protrusion 3, and then the recess 6 is fitted into the protrusion 3 and the nut 2 is tightened, the result shown in FIG. As shown, even if the nut 2 is inclined with respect to the axis O of the bolt 21, the angle of inclination is usually within 3 degrees, so the tapered surface 7 of the recess 6 extends over a wide range on the tapered surface 4 of the protrusion 3. make surface contact. Therefore, the shearing force P acting in the direction perpendicular to the axis 0 of the bolt 210 due to the wedge effect caused by the engagement of both tapered surfaces 4.7 is applied to the thread 15a to the inside of the protrusion 3.
15G and the threads 22a to 2 of the bolt 21 that are screwed together
2b, and exhibits an excellent locking effect. Further, the screw threads 15a and 22a are not locally deformed.

The above-mentioned loosening prevention effect can be obtained by turning the nut 1.2 in the opposite direction, tightening and fixing the fastened member 20 with the nuts 1 and 2 having the recess 6, and then loosening the nut 1 with the protrusion 3. The same applies when used as a stopping means. Further, the tapered surface 4 of the protrusion 3 may be formed concentrically with the screw hole 5 thereof, and the center line B of the tapered surface 7 of the recess 6 may be eccentric with respect to the axis O of the screw hole 8.

As described in detail, according to the present invention, even if one of the nuts used as the locking means is screwed together at an angle with respect to the axis of the bolt threaded portion, an excellent locking function is exhibited.
In particular, even when there is a large gap in the threaded joint between the nut and bolt, a sufficient locking effect can be obtained, and the thread of the nut and the thread of the bolt screwed into it can be locally deformed. Never. Therefore, even if it is loosened once and then reused, a good locking effect can be obtained, and the practical effect is extremely large.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional front view of a nut loosening device according to the present invention, FIG. 2 is a partially cutaway front view of the same nut in a separated state, and FIG. 3 is a longitudinal sectional front view of a conventional device. 1.2...Nut 3...Protrusion 4.7...
Tapered surface 6... Recess 5.8... Screw hole
α, β... Inclination angle patent applicant Hardrock Industries Co., Ltd. Figure i Figure 2

Claims (2)

[Claims] (1) Consisting of a pair of nuts, one nut is provided with a protrusion that surrounds the screw hole and has a tapered outer peripheral surface with a truncated conical shape, and the other nut has an inner peripheral surface with a truncated conical shape. In the device, the tapered surface 4 of the protrusion 3 is provided with a recess that is formed on a tapered surface of the shape and that fits into the protrusion, and either the protrusion or the recess is eccentric with respect to the axis of the screw hole. The inclination angle α of the recess 6
A nut loosening device characterized in that the inclination angle β of the tapered surface 7 is larger than the inclination angle β of the tapered surface 7. (2) The inclination angle α of the tapered surface 4 of the protrusion 3 is approximately 10
The nut loosening device according to claim 1, wherein the inclination angle β of the tapered surface 7 of the recess 6 is about 7 degrees.