JP4259688B2 - Bolt / nut locking structure - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a bolt / nut loosening prevention structure that is attached to a tip of a bolt and temporarily fixes a nut or prevents the nut from loosening or dropping.
[0002]
[Prior art]
For fixing structures, bolts and nuts are often used in various fields. For example, it is widely used from steel-framed buildings, steel towers, road installations to automobiles and electrical appliances.
Since the nut 2 fastened to the bolt 1 is easily loosened by vibration, external force, etc., simply attaching it, the spring washer 3 is usually sandwiched when the nut 2 is mounted as shown in FIG. Yes, but often not enough in some situations. For this reason, as shown in FIG. 7B, a method (double nut method) in which another nut 2 is screwed onto the bolt 1 on which the nut 2 is mounted and the nuts are fastened and fixed together is employed. In some cases, application and fixing are performed with rock paint or the like.
However, with the double nut method, it is surely fixed immediately after tightening, but once the nut is loosened by an impact such as vibration or something hits for a long time, the two nuts can rotate freely. As a result, the nut may fall off the bolt at the end. There is also the inconvenience that a box wrench cannot be used when tightening the nut on the back side.
With the rock paint method, there was a possibility of falling off due to insufficient adhesion and strength of the dried paint and deterioration over time.
[0003]
[Problems to be solved by the invention]
The present invention has been devised to solve such problems, and can be easily attached to the leg of a bolt screwed with a nut to reliably prevent loosening over a long period of time. An object of the present invention is to provide bolts and nuts that are not likely to deteriorate with time.
[0004]
[Means for Solving the Problems]
In order to achieve the above object, the bolt / nut loosening prevention structure of the present invention has a bolt, a nut screwed into the bolt, and a coil spring fitted in a screw groove of a leg portion of the bolt protruding from the nut. The rotation of the nut in the removing direction is restricted by the coil spring. A part of the outside of the wire of the coil spring fitted in the screw groove of the bolt protrudes from the screw thread of the bolt, and if a cap that restricts the radial extension of the protruding portion is attached, a stronger locking is obtained. A coil spring may be attached by fixing at least one end of the coil spring to the inside of the cap.
[0005]
[Action]
When the coil spring 7 having an inner diameter slightly smaller than the screw outer diameter of the leg portion 4 of the bolt 1 is fitted into the screw groove of the leg portion 4 of the bolt 1, the element wire 7a of the coil spring 7 is as shown in FIG. The wire 7a is fitted so as to fill the screw groove, and each part of the strand 7a is pressed toward the axial center of the bolt by the elastic force of the strand 7a. As a result, as shown in FIG. 1B, the contact portion C between the wire 7a and the inside of the screw groove is pressed, and a strong frictional force is generated, and the coil spring 7 is firmly attached to the screw groove of the leg portion 4 of the bolt 1. Fixed. For this reason, if the coil spring 7 is attached to the leg portion 4 at a position adjacent to the nut 2 to be prevented from loosening, the nut 2 is prevented from rotating at this portion and is not loosened. When the tip of the wire 7a of the coil spring 7 enters the gap between the nut and the bolt, the rotation of the nut is effectively restricted. For this reason, for example, as shown in FIG. 1 (d), the tip of the strand 7a is preferably tapered so as to easily enter the gap between the nut and the bolt.
Further, as shown in FIG. 1 (c), the strand 7a that is thick enough to protrude from the thread groove is used, and the cap 8 touches and covers the outer periphery of the coil spring 7, thereby preventing the strand 7a from being lifted from the thread groove. .
[0006]
Embodiment
An example of the locking 10 using the bolt / nut locking structure of the present invention is shown in FIG. The locking stopper 10 is made of an elastic metal or resin and has a knob portion 11 and a coil spring portion 12. In order to fit this into the leg 4 of the bolt 1 to which the nut 2 is screwed, the knob 11 is rotated in the direction A as shown in FIG. Screw in so that the strand 14 may penetrate along a thread groove from a part. Since the coil spring portion 12 has an inner diameter slightly smaller than the outer diameter of the screw portion 5 of the bolt 1, when the element wire 14 enters the screw groove, it is pressed against the slopes on both sides of the screw groove and is restrained by the frictional force. However, when the knob portion 11 is turned in the mounting direction (A direction) of the coil spring portion 12, the coil spring portion 12 is deformed in a direction in which the diameter is enlarged. Is reduced and can be screwed in smoothly.
[0007]
On the contrary, when the knob portion 11 is turned in the direction of removal (reverse to the A direction), the coil spring portion 12 is pulled in the direction in which the diameter is reduced, so that the wire 14 of the coil spring portion 12 is stronger than the screw groove. Pressed against the slope and prevented from rotating. That is, when the knob portion 11 is turned and the coil spring portion 12 is attached to the bolt, it is easy to turn in the forward direction (mounting direction: A direction) but difficult to turn in the reverse direction (detachment direction). It does not return in the direction of separation due to unexpected impact. As shown in FIG. 2C, the knob portion 11 is turned until the wire tip 13 enters the gap between the bolt 1 and the nut 2 to complete the mounting. In order to firmly restrict the movement of the nut 2, it is preferable to push the wire tip 13 deeply into the gap between the bolt 1 and the nut 2. When the nut 2 tries to turn in the loosening direction (direction B), the wire tip 13 is deeply caught in the gap between the bolt 1 and the nut 2, and the nut 2 is fixed more and more firmly.
[0008]
The required number of turns of the coil spring portion 12 is set according to design conditions such as the diameter of the coil spring portion 12, the diameter and strength of the wire 14. The knob portion 11 may be provided sideways as shown in FIG. In addition, as shown in FIG.
The hardness of the spring wire 14 is determined in consideration of the material of the bolt and nut. A somewhat soft material may be used so that the bolt and nut are not damaged when the wire tip 13 is bitten.
Even if the coil spring portion 12 is too long, the effect of preventing loosening can be obtained, but the length of the coil spring portion 12 of the loosening stop 10 is set corresponding to the length of the leg portion 4 of the bolt 1 to be mounted. Is preferred.
[0009]
If a spring with relatively weak elasticity is used as necessary, it can be attached by simply pushing it in without turning the knob part 11, and attachment / detachment becomes easy. In this case, if the cap 20 that covers the outer periphery of the loosening stopper 10 is attached, the loosening stopper 10 is more reliably attached. The cap 20 has, for example, a shape as shown in FIG. 4A, is made of an elastic metal or resin, and is attached from the axial direction of the bolt 1. The inner surface of the attached cap 20 presses a portion protruding from the groove of the strand 14 of the locking member 10 fitted in the groove of the screw portion 5 of the bolt 1. Therefore, in this state, the locking stopper 10 is most reliably fixed. The shape of the cap 20 can be as shown in FIG. 4B, and is used by inserting it in the direction of the arrow.
The loosening stopper 10 and the cap 20 do not necessarily have to be separate bodies, and may be integrated in advance. FIG. 5 shows an example of the cap-integrated loosening stopper 30. In (a), the resin-made cap part 31 with a certain degree of flexibility is in contact with the outer periphery of the spring part 32 on the inside, and one end of the spring passes through the inside of the cap part 31 and reaches the knob part 33. This is mounted by turning the knob portion 33 on the leg portion 4 of the bolt 1 protruding from the nut 2 for preventing loosening. At the time of checking the tightening state of the nut 2, a jig or the like is hooked on the knob portion 33 and pulled out to be removed. At this time, since the spring portion 32 cannot be rotated in the detaching direction, the cap portion 31 and the spring portion 32 are destroyed and removed, and a new locking member 30 is attached. The cap portion 31 (b) in the shape of a nut is used in the same manner, but is suitable when the leg portion 4 of the bolt 1 is long.
By using the colored cap 20 or cap part 31, information such as the mounting / construction time of the part can be added according to the type of color. Further, for example, even if there is an unexpected situation such as a steel tower using many bolts and nuts, it can be confirmed at a glance from a relatively remote position even if the loosening stopper has dropped.
Although the above has been described with a right-hand thread, it is needless to say that the present invention can be similarly applied to a left-hand thread.
Moreover, the cross-sectional shape of the strand 7a can consider an ellipse (a), a trapezoid (b), etc., as shown in FIG.
[0010]
【The invention's effect】
As described above, the loosening prevention structure according to the present invention has a structure in which the wire of the coil spring portion having an inner diameter slightly smaller than the outer diameter of the bolt is fitted into the thread groove of the bolt leg portion. For this reason, a strand is firmly fixed to a screw groove by frictional force.
When installing the locking mechanism, the thread is smoothly fed in the mounting direction, but the locking mechanism cannot be turned in the removal direction, and the wire enters the gap between the bolt and nut, ensuring that the nut Can be prevented from loosening or falling off. In addition, it is possible to prevent loosening that can be easily mounted at a very low cost compared to, for example, a double nut system. If a cap that restricts the lifting of the spring or a cap-integrated type is used, it is more reliable.
[Brief description of the drawings]
FIG. 1 is a loosening prevention structure (a) of the present invention, a thread cross section (b), (c), and a wire tip shape (d).
[Fig. 2] An example of the locking device of the present invention [Fig. 3] Another example of the locking device of the present invention [Fig. 4] An example (a) and another example (b) of the cap of the present invention.
FIG. 5 shows an example (a) and another example (b) of the cap-integrated type locking device of the present invention.
[Fig. 6] Example of cross-sectional shape of spring wire [Fig. 7] Conventional washer (a) and double nut (b)
[Explanation of symbols]
1: Bolt 2: Nut 3: Spring washer 4: Leg part 5: Screw part 7: Coil spring 7a: Wire 8: Cap 10: Locking prevention 11: Knob part 12: Coil spring part 13: Wire tip 14: Wire 20 : Cap 30: Locking prevention 31: Cap part 32: Spring part 33: Knob part

Claims (3)

A coil spring portion fitted into a thread groove of a leg portion of the bolt protruding from a nut screwed to the bolt;
A knob portion extending from the element wire of the coil spring portion at least in a direction away from the coil spring portion and bent so as to cross a substantially central axis of the coil spring portion,
A bolt / nut loosening prevention device in which rotation of the nut in the removing direction is restricted by the coil spring portion. The bolt / nut loosening prevention tool according to claim 1, wherein at least a part of the tip of the wire of the coil spring portion on the opposite side of the knob portion is fitted into a screw groove. The bolt / nut loosening prevention tool according to claim 1 or 2, wherein the coil spring portion is wound at an equal pitch.

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