JPH10246215A - Insert bolt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent occurrence of looseness, caused by the co-rotation of an inert bolt when a bolt or a nut screwed in the insert bolt is unscrewed under a condition that the insert bolt is attached to a soft board and the like. SOLUTION: Threads 4 are formed around the periphery of a shaft body 1 which has a screw hole 2 in its head part and whose this is narrowed. Projected pieces 5 deformed by resistance at the time of screwing are arranged among the adjacent threads 4. In screwing when this insert bolt is screwed into a soft board, the projected pieces 5 are inclined to the following side of a screwing direction, and rotation in the loosening direction of the insert bolt is prevented by the engaging force of the projected pieces 5 inclined.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insert bolt screwed into a soft board such as ALC.

[0002]

2. Description of the Related Art When mounting various articles on soft boards, insert bolts are screwed into the boards, and bolts or nuts are screwed into screw holes or screw shafts formed in the heads of the insert bolts. The parts are fixed by tightening bolts or nuts.

[0003]

The insert bolt known in the prior art has a structure in which a thread is formed on the outer periphery of a shaft body that is tapered, so that the engaging force with soft boards is weak. When the bolts or nuts for mounting articles, which are screwed to the insert bolts, are loosened, they may loosen due to twisting, and there is a problem in the stability of mounting to soft boards.

[0004] It is an object of the present invention to prevent loosening due to twisting when a bolt or nut for attaching an article is removed in a state of attachment to a soft board. It is to provide an insert bolt.

[0005]

In order to solve the above-mentioned problems, according to the present invention, an outer periphery of a shaft body having a tapered end and a head portion provided with a screw engaging portion and a wrench engaging portion is provided. A thread is formed from the leading end to the trailing end, and between the adjacent threads, a plurality of thin-walled protruding pieces that fall down on the trailing side in the rotational direction due to resistance during screwing are adopted. I have.

The insert bolt having the above configuration is
When the protruding piece is screwed into the soft boards, the protruding piece is caused to fall, and loosening due to engagement of the protruding piece with the internal tissue of the soft board is prevented.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, the shaft body 1 has a thin tip, a screw hole 2 is formed in the head portion as a screw engaging portion, and a wrench engaging portion 3 formed of a square hole on the bottom surface. Is provided.

A thread 4 is provided on the outer periphery of the shaft 1, and a plurality of thin-walled protruding pieces 5 are formed in the circumferential direction between the adjacent threads 4 so as to be linearly arranged in the axial direction of the shaft 1. I have.

Here, as shown in FIG. 4 (I), the thread 4 may have a triangular cross-section in which the leading flank 6a and the trailing flank 6b have the same flank angle during screwing. As shown in FIG. 4 (II), the flank angle of the leading flank 6a may be larger than the flank angle of the trailing flank 6b, and the cross-sectional shape may be trapezoidal. In the trapezoidal thread 4, when a pull-out force acts on the insert bolt, the pull-out force is received by the follower flank 6b having a small flank angle, so that an insert bolt with excellent pull-out resistance can be provided.

The protruding piece 5 is so strong that it falls down on the trailing side in the rotational direction due to resistance when the insert bolt is screwed.

The protruding piece 5 may be provided so as to protrude from a screw groove bottom surface between the adjacent screw threads 4, as shown in FIG.
You may make it protrude from the intersection part of the screw thread 4 and the screw groove bottom face.
Further, as shown in FIG. 5 (II), the length may extend between adjacent screw threads 4.

The protruding piece 5 shown in FIG. 1 and FIG. 5 (I) is formed by press forming after the formation of the screw thread 4, while the protruding piece 5 shown in FIG. The insert bolt is formed at the same time as die casting.

[0014] The mounting of the insert bolt having the above structure is performed by rotating a wrench by engaging a wrench with the wrench engaging portion 3.
Screw directly into the soft board without forming a pilot hole.

When the insert bolt is screwed into the soft board, the protruding piece 5 provided between the adjacent screw threads 4 has a weak stiffness, so that the protruding piece 5 falls inside the soft board in a state of falling backward in the rotation direction. invade.

For this reason, the rotational resistance due to the insertion of the insert bolt is relatively small, and the insertion of the insert bolt is smooth. Further, since the protruding piece 5 that has fallen is raised when the insert bolt is rotated in the loosening direction and strongly engages with the internal structure of the soft boards, it is possible to prevent the insert bolt from becoming loose.

Therefore, when removing the bolt screwed into the screw hole 2, there is no inconvenience that the insert bolt is turned around.

FIGS. 3 (I) and (II) show other examples of the head shape of the insert bolt. In FIG. 1I, a flange 7 is provided on the head of the shaft body 1. (II) is the shaft 1
A screw shaft 8 as a screw engaging portion is provided on a flange 7 formed on the head of the screw shaft 8, and a wrench engaging portion 9 formed of a square hole is provided on a tip end surface of the screw shaft 8.

In the insert bolt shown in FIG. 3 (II), an article is mounted on a soft board by a nut which is screw-engaged with the screw shaft 1.

[0020]

As described above, according to the present invention, the projecting piece provided between the screw threads falls down in the rotating direction at the time of installation by screwing in the insert bolt, and the projecting piece that has fallen is inserted bolt. In order to engage with the internal structure of the soft board at the time of rotation in the loosening direction, there is no inconvenience that the insert bolt is twisted and loosened when removing the bolt or nut screwed to the insert bolt. A strong and stable attachment state can be obtained.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of an insert bolt according to the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 shows another example of the head shape of the insert bolt, in which (I) is a front view and (II) is a partially cutaway front view.

FIG. 4 (I) is a cross-sectional view showing an enlarged part of the insert bolt, and FIG. 4 (II) is a cross-sectional view showing another example of the thread.

FIGS. 5 (I) and (II) are front views showing another example of a protruding piece of the same insert bolt.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shaft 3 Wrench engagement part 4 Thread 5 Protrusion

Claims (1)

[Claims] 1. A tip is thinned, a screw engaging portion is provided on a head,
A thin wall is formed on the outer periphery of the shaft body provided with the wrench engaging portion, from the leading end to the trailing end, and between the adjacent threads, falling on the trailing side in the rotational direction due to resistance at the time of screwing. Insert bolt with multiple thick protrusions.