JPH09280235A - Locking structure of screw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screw locking structure the manufacturing of which is facilitated by a method wherein an elastic member having an elastic force in the penetrating direction is mounted in a mounting hole, pierced with a screw shaft, in such a state that the end part thereof is protruded from a hole port. SOLUTION: A mounting hole 21 is formed in a screw shaft 2 such that it extends therethrough and an elastic member 3 is arranged therein. The elastic member 3 is a compression spring made of a metal, the central part of a coil has a large diameter (b), and two end parts have a small diameter (c). The outside diameter of the large part 31 has size enough to allow close fitting of it in a mounting hole 21 and an overall length during non-compression is slightly longer than the hole length of the mounting hole 21. When the elastic member 3 is pressed in the mounting hole 21 and fixed through close fitting-in of large part 31, a small part 32 is slightly protruded from a hole part. When a bolt is joined in a screwed-in state with a female screw part, the tip part of the elastic member 3 is pressed in the mounting hole 21 and through the repulsion force thereof, frictional resistance between the tip part and a female screw surface is increased and forms locking protection of the shaft part 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw locking structure for use in a place where it is necessary to maintain a loosely tightened state.

[0002]

2. Description of the Related Art In a structure in which a male screw and a female screw are formed in advance like a bolt and nut, and the screws are screwed together to connect or clamp members, the screw is prevented from loosening. As a conventional means, a nut member is double screwed, a spring washer is interposed, a blocking member such as an insertion pin or a wire hook for blocking the rotation of the screw member is attached,
It is known to use a split pin type bolt having a repulsive force against a compressive force generated when the taper shaft portion of the bolt itself is vertically divided. However, the above-mentioned loosening prevention means is also the loosening prevention means in the state where the screw is firmly tightened,
It may also be required to prevent loosening when loosely tightened.

Therefore, an elastic member is formed on one of the screw surfaces of the screw portion to be screwed first, which is approximately coincident with the screw advancing direction, and the other screw surface projects from the screw surface in correspondence with the recess. Was proposed (Japanese Patent Laid-Open No. 6-22941).
No. 2).

[0004]

A vertical groove groove is formed in the loosening prevention screw shaft, and when the groove groove portion approaches due to an external force, the screw shaft has a smaller outer diameter and the screw fits. May not be effective, and it is troublesome to manufacture the grooved groove on the screw shaft and to mount the elastic member in the grooved groove, which is a complicated work. Therefore, the present invention proposes a screw locking structure that is easier to manufacture.

[0005]

A screw loosening preventive structure according to the present invention has an elastic hole having a mounting hole penetrating the screw shaft and having elasticity in the mounting hole in the hole penetrating direction. The member is characterized in that the elastic member is mounted such that the end portion of the elastic member projects from the hole opening.

Further, a metal coil is adopted as the elastic member, the central portion of the coil has an outer diameter for tightly fitting in the mounting hole, and both end portions have a smaller diameter than the central portion, and the entire length is the hole length of the mounting hole. It is characterized in that it is made slightly longer and the metal coil is press-fitted into the mounting hole.

Therefore, when the screw shaft is screwed into the female screw portion, the elastic member projects from the hole opening of the mounting hole, so that the projecting tip end portion of the elastic member is naturally pushed into the hole and the elastic member. Repulsive force serves as a resistance force for the screwing rotation of the screw, and this resistance force acts as a loosening stopper.

[0008]

Next, an embodiment of the present invention will be described. 1 to 4 show a first embodiment of the present invention. In this embodiment, the present invention is applied to a bolt, and the bolt has a head portion 1 and a shaft portion 2 as in a general bolt. The head portion 1 is provided with a shape to which the rotation is applied, for example, a driver groove 11, and the shaft portion 2 is naturally engraved with a screw a. In order to apply the present invention to the above bolt, a mounting hole 21 penetrating the shaft portion (screw shaft) 2 is bored, and the elastic member 3 is provided in the mounting hole 21.

The elastic member 3 is a compression coil spring made of metal. The central portion of the coil has a large diameter b, and both end portions have a small diameter c.
Then, the whole is made into a vial shape, and the outer diameter of the large-diameter portion 31 is set to a size that can be tightly fitted in the mounting hole 21. Further, its entire length (when not compressed) is slightly longer than the hole length of the mounting hole 21. The elastic member 3 is mounted on the shaft portion 2 by press-fitting the elastic member 3 into the mounting hole 21, and the elastic member 3 is fixed by tightly fitting the mounting hole 21 and the large diameter portion 31, and the small diameter portion 32. Will be mounted slightly protruding from the hole mouth.

When the bolt is screwed into an appropriate female screw portion, the tip portion (small diameter portion 32) of the elastic member 3 is pushed into the mounting hole 21, and the repulsive force of the elastic member 3, that is, the tip portion ( The frictional resistance between the small-diameter portion 32) and the female screw surface becomes sufficiently large, which serves as rotation resistance of the shaft portion 2 and prevents the shaft portion 2 from loosening.

Further, as shown in FIGS. 5 to 7, the elastic member 3a is made of vertically long rubber at both ends of the body portion 33 which is tightly fitted in the mounting hole 21 without using the metal coil as in the above embodiment. A projecting elastic portion 34 may be adopted, and the mounting hole 21
Body part 33 so that the elastic part 34 slightly protrudes from the hole opening of
Is fixed in the mounting hole 21, and the bolt A advances into the female screw hole 41 of the nut 4 screwed with the bolt A as illustrated in FIG. 7 corresponding to the bolt provided with the elastic member 3a. When an appropriate number of recessed ridges 42 are formed in the same direction and the two are screwed together, the tip end of the elastic member 34 of the elastic member 3a causes the recessed ridges 4
The bolt A is fitted into the bolt 2, and this fitting becomes a click feeling of the bolt A, and the loosening of the bolt A is realized in the fitted state.

[0012]

As described above, the present invention has a screw locking structure in which a mounting hole is formed in a screw shaft portion to be screwed, and an elastic member protruding from the screw shaft is attached to the mounting hole. The compression repulsive force of the elastic member at the time of screwing rotation by the shaft serves as a resistance force for the screwing rotation of the screw shaft to prevent the loosening, and not only the tightening state but also the loose tightening state. Even if it is screwed, it can effectively prevent loosening.

[Brief description of drawings]

FIG. 1 is a perspective view of a bolt according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the bolt.

FIG. 3 is a front view of the elastic member.

FIG. 4 is a cross-sectional view of the mounting hole portion.

FIG. 5 is a perspective view of an elastic member according to another embodiment of the present invention.

FIG. 6 is a partially cut front view of a bolt using the elastic member.

FIG. 7 is a plan view of a nut screwed with the bolt.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Head part 11 Driver groove 2 Shaft part (screw shaft) 21 Mounting hole 3,3a Elastic member 31 Large diameter part 32 Small diameter part 33 Body part 34 Elastic part 4 Nut 41 Screw hole 42 Recessed line

Claims (2)

[Claims] 1. A screw shaft is provided with a mounting hole penetrating the screw shaft, and an elastic member having elasticity in a hole penetrating direction is provided in the mounting hole such that an end of the elastic member projects from a hole opening. A structure that prevents the screws from loosening by being attached. 2. The screw loosening preventive structure according to claim 1, wherein a metal coil is adopted as the elastic member, and a central portion of the coil has an outer diameter for tightly fitting in the mounting hole, and both end portions are central. A screw locking structure, wherein the diameter is smaller than that of the portion and the overall length is slightly longer than the hole length of the mounting hole, and the metal coil is press-fitted into the mounting hole.