JP2002130241A - Dropping-out preventing mechanism of nut for fastening tool consisting of bolt and nut - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dropping-out preventing mechanism of a nut for sure prevention of the possibility of dropping-out of a nut from a bolt due to outside vibration or the like. SOLUTION: The dropping-out prevention mechanism is comprised of the bolt 1 forming a recessed portion 13 on a shaft portion 11, having a screw thread 12 and the nut 2 forming a slant face 20 in one face.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for preventing a nut from falling off in a fastener comprising a bolt and a nut.
In particular, external vibration is added to the frequency, thereby loosening and falling off the nut, which may lead to a major accident. About.

[0002]

2. Description of the Related Art In general, a fastener composed of a number of bolts and nuts is used in a train wire support mechanism and the like, and this support mechanism is frequently used as the train travels or due to wind pressure or the like. Violent external vibrations can cause loosening of the fasteners, eventually causing the nuts to fall off the bolts and cause a major accident.

Therefore, conventionally, a diametrically inserted through hole for a split pin is provided at an end of a bolt, a nut is screwed into the bolt to fasten a member to be fastened, and then the split pin is inserted into the through hole. The lower end of the split pin was then opened through the split groove to prevent the nut from falling off the bolt.

[0004]

However, in the fastening work of the bolt and the nut, the worker often forgets to insert the split pin into the insertion hole, or inserts the split pin into the insertion hole. The operator forgot to open the lower end of the nut, which caused the split pin to come off the bolt, causing the nut to come off.

[0005]

Therefore, in order to solve the above-mentioned conventional inconvenience, a bolt and a nut are provided, and a threaded portion necessary for fastening an object to be fastened to a shaft portion of the bolt is left. A concave portion having a width that allows the intervention of the nut is provided along the periphery of the shaft portion.

[0006] In the above, it is preferable that the fine shaft portion formed by the concave portion is provided eccentrically with respect to the shaft portion, and that the fine shaft portion formed by the concave portion is formed into a conical shape in the longitudinal direction. May be formed.

[0007] More preferably, the nut has an inclined surface on one surface. Also, in order to prevent the nut from falling off more securely, the locking piece, the top piece, and this piece form a downward U-shape so that the plate piece can be bent and the end of the shaft can be sandwiched in the axial direction. The engaging piece is formed into a shape, and engages with the engaging piece to engage the thin shaft portion, and then extends downward and divergently continuously through an opening end having a width slightly smaller than the diameter of the thin shaft portion. , A guide groove which is open at the lower end, and a claw piece which is engaged with an end portion of the shaft portion is provided at the lower end of this piece.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a bolt according to an embodiment of the present invention; FIG.
The top view of the nut 2 is each shown.

The bolt 1 is formed by applying a screw 12 to a shaft 11 having a regular hexagonal head 10 at one end thereof. B
5 (see FIG. 5), a recess 13 having a width t necessary for the nut 2 to intervene is provided, leaving a sufficient threaded portion 12a for fastening with the nut 2.

The concave portion 13 is formed along the periphery of the shaft portion 11, and a narrow shaft portion 14 is formed at the position of the concave portion 13.
Is provided. The fine shaft portion 14 may be provided concentrically with respect to the shaft portion 11, but is preferably provided eccentrically, as apparent from FIGS.

The nut 2 has an inclined surface 20 cut obliquely on one of the front and rear surfaces, and the width t of the concave portion is set so that the thickest portion thereof can be interposed. Is done.

The bolt 1 and the nut 2 constructed as described above
In the conventional method, two objects A and B to be fastened are fastened as shown by a virtual line in FIG.

When the nut 2 is loosened from this state due to the action of external vibration or the like, and then the nut 2 comes off from the threaded portion 12a of the shaft portion 2, as shown by a solid line in FIG. Then, the nut 2 falls into the recess 13.

Therefore, the nut 2 can be stopped at the position of the concave portion 13 and can be prevented from dropping from the bolt 1.

By the way, in the state described above, when the nut 2 is interposed in the recess 13 of the bolt 1, the nut 2 moves extremely complicatedly in the recess 13 due to the action of external vibration or the like.

That is, the nut 2 rotates around the thin shaft portion 14 in the recess 13, swings in a direction perpendicular to the shaft center, or moves in the shaft center direction. Make extremely complex movements that cannot be predicted.

In the above-described configuration, for example, when the fine shaft portion 14 is formed concentrically with respect to the shaft portion 11, the extremely complicated movement of the nut 2 causes the nut 2 Has a possibility of rotating concentrically with respect to the thin shaft portion 14.

The fact that the nut 2 rotates concentrically with respect to the thin shaft portion 14 means that the nut 2 also rotates concentrically with respect to the shaft portion 11, and the nut 2 concentrically rotates. The nut 2 may be screwed into the threaded portion of the end portion 11 a of the shaft portion 11, though extremely rarely, due to the pivotal movement.

The nut 2 is connected to an end portion 11a of the shaft portion 11.
The possibility of screwing into the threaded portion is increased when a nut having a configuration in which both surfaces are opposed to each other with a vertical surface as in the related art is used.

The nut 2 is connected to the end portion 11 of the shaft 11.
When the nut 2 is slightly screwed into the threaded portion a, the nut 2 thereafter forms a sufficient threaded engagement with the threaded portion, and there is a risk that the nut 2 will eventually fall off the end portion 11a.

On the other hand, when the thin shaft portion 14 is provided eccentrically, the nut 2 is moved by the external vibration action.
However, even if the nut 2 is rotated concentrically, the nut 2 is not in a concentric relationship with the shaft 11, so the probability that the nut 2 is screwed into the threaded portion of the end portion 11a of the shaft 11 is extremely low. Therefore, the nut 2 can be more reliably prevented from falling off.

The relationship between the movement of the nut 2 due to the above-described external vibration action and the threaded portion of the end portion 11a of the bolt 1 is the same when a conventional nut in which both surfaces of the nut 2 are vertically opposed to each other is used. It is.

In other words, the bolt 1 having the thin shaft portion 14 formed concentrically with respect to the shaft portion 11 has a thinner shaft portion than the conventional nut having both surfaces opposed to each other with a vertical surface. It can be said that a case where a nut having a conventional configuration is used for the bolt 1 in which the nut 14 is formed in an eccentric shape is more advantageous for preventing the nut from falling off.

According to the present invention, in order to further prevent the nut from falling off, one of the surfaces is formed as an inclined surface 20.
It is a requirement to use the nut 2 to be used.

According to this configuration, the nut 2 is
When external vibration is applied to the nut 2 in the state shown by the solid line in FIG. 4 interposed in the nut 2, the nut 2 has a different mass in a plane of 360 degrees and an end portion 11a of the shaft portion 11.
Since the surface of the nut 2 that is in contact with the vertical wall surface p is an inclined surface, there is little possibility that the nut 2 simply moves in the direction perpendicular to the axis of the thin shaft portion 14, and therefore, the nut 2 The possibility that the nut 11 is screwed into the threaded portion of the end portion 11a is far less than that of a conventional nut whose both surfaces are vertically opposed to each other. Drop prevention can be more reliably achieved.

FIG. 5 shows a configuration of the above-described configuration,
4 shows another embodiment in the case of forming a conical shape in the longitudinal direction, that is, forming the shaft diameter gradually smaller from one end to the other end. According to the method described above, the nut 2 intervening in the recess 13 is, as shown by the phantom line in FIG. In the state in which the nut 2 is interposed, the nut 2 is inclined with respect to the vertical wall surface p of the recess 13, so that even in this configuration, it is possible to more reliably prevent the nut 2 from falling off. .

FIG. 6 shows a fastener comprising a bolt 1 having a concave portion 13 formed in a shaft portion 11 and a nut 2 having an inclined portion 20 on one surface, in order to further prevent the nut 2 from falling off. Next, another embodiment in which the stopper 3 is provided is shown.

As shown in FIG. 7, the stopper 3 is formed by bending a long plate piece 30 made of synthetic resin or steel plate in a downward U-shape at a broken line position shown by a broken line.

Specifically, a locking piece 31 sufficiently longer than the diameter of the shaft 11 of the bolt 1, a top piece 32 having a width adapted to the length of the end portion 11a of the bolt 1, and And a contact piece 33 slightly longer than the diameter of the shaft portion 11 are formed in a downward U-shape.

The locking piece 31 has an engagement hole 34 of a size suitable for fitting the thin shaft portion 14 and the small shaft portion 14.
And a guide groove 36 which extends continuously from the open end 35 slightly smaller than the diameter of the guide groove 36 and is open at the lower end.

A slit 37 extending from the apex position of the engagement hole 34 to the top piece 32 is provided, and a lower edge of the piece 32 is engaged with the outer peripheral surface of the end portion 11a of the shaft portion 11. An inwardly bent rib 38 is provided.

As shown in FIG. 6, the stopper 3 having the above-described structure is arranged so that the end portion 11a of the shaft portion 11 is sandwiched between the locking piece 31 and the contact piece 32, for example, from the top to the top. 3
Press 1.

Then, the thin shaft portion 14 is guided into the guide groove 36, and then the open end 35 of the guide groove 36 is
The narrow shaft portion 14 is temporarily pushed out through the
4 is engaged.

In this manner, by attaching the stopper 3 to the bolt, as shown in FIG.
Is interposed between the nut 2 and the end portion 11a of the shaft portion 11, so that the nut 2
However, even if the nut 2 is screwed into the threaded portion of the end portion 11a due to external vibration or the like, the nut 2 is restrained by the locking piece 31 and the nut 2 is completely prevented from dropping off the bolt 1. . This is the same when a nut having a conventional configuration in which both surfaces face each other with a vertical surface is used.

[0035]

As described above, the present invention is configured as described above, so that the nut can be prevented from falling off from the bolt only by the operation of screwing the nut to the bolt to fasten the two members to be fastened. This has the advantage that it can be reliably prevented.

Further, according to each of the second, third and fourth aspects of the present invention, it is possible to more reliably prevent the nut from falling off.

Further, according to the fifth aspect of the present invention, there is an advantage that the nut can be completely prevented from falling off.

[Brief description of the drawings]

FIG. 1 is a plan view of a bolt.

FIG. 2 is a sectional view taken along line II of FIG. 1;

FIG. 3 is a plan view of a nut.

FIG. 4 is a plan view showing a relationship between a bolt and a nut.

FIG. 5 is a plan view of a bolt according to another embodiment.

FIG. 6 is a plan view showing the relationship between a bolt and a nut in another embodiment.

FIG. 7 is a developed plan view of the stopper.

FIG. 8 is a plan view of a stopper.

FIG. 9 is a sectional view of a stopper.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bolt 2 Nut 3 Stopper 11 Shaft portion 11a End portion 12 Screw 13 Depressed portion 14 Fine shaft portion 20 Inclined surface 31 Locking piece 32 Top piece 33 This piece 34 Engagement hole 35 Open end 36 Guide groove 37 Slit

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tamura 2-2-2-2 Yoyogi, Shibuya-ku, Tokyo East Japan Railway Company (72) Inventor Norio Okumura 1-2-2 Ikenota, Taito-ku, Tokyo No. 3 Nihon Densetsu Kogyo Co., Ltd. (72) Inventor Tsutomu Fujita 1-2-3 Ikenohata, Taito-ku, Tokyo Nihon Densetsu Kogyo Co., Ltd. (72) Inventor Soshiro Hieda One Hiromachi, Shinagawa-ku, Tokyo Chome San-No-San No.3 Japan Overhead Wire Industry Co., Ltd.

Claims (5)

[Claims] 1. A bolt and a nut, and a recessed portion having a width allowing a nut to be interposed is formed around a shaft portion of the bolt while leaving a threaded portion necessary for fastening a body to be fastened to the shaft portion. A nut-preventing mechanism for a fastener comprising a bolt and a nut, the mechanism comprising: 2. A mechanism for preventing a nut from falling off in a fastener comprising a bolt and a nut according to claim 1, wherein the thin shaft formed by the recess is provided eccentrically with respect to the shaft. 3. A mechanism for preventing a nut from falling off in a fastener comprising a bolt and a nut according to claim 1 or 2, wherein the narrow shaft formed by the recess is formed in a conical shape in the longitudinal direction. 4. A mechanism for preventing a nut from falling off in a fastener comprising a bolt and a nut according to claim 1, wherein the nut has an inclined surface on one surface. 5. The locking piece is formed in a downward U-shape by a locking piece, a top piece and a contact piece so that the plate piece is bent so that an end portion of the shaft portion can be sandwiched in the axial direction. An engaging hole for engaging the thin shaft portion, and a guide groove extending downward and continuously divergently through an opening end having a width slightly smaller than the diameter of the thin shaft portion, and opened at the lower end. 5. A mechanism for preventing a nut from falling off in a fastener comprising a bolt and a nut according to claim 1, further comprising a claw piece provided on a lower end of the piece to lock the end portion of the shaft.