JPS6326569Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a bolt that can be tightened and fixed without damaging the surface of the round steel bar, etc., when supporting the round steel bar, etc., via a support, for example.

[Conventional technology]

Conventionally, for example, when welding round steel bars for reinforced concrete by gas pressure welding, etc., in order to temporarily support and fix the round steel bars, the round steel bars were supported on special supports and fixed by tightening with ordinary bolts. .

However, according to such conventional technology, the tip end surface of the bolt rotates while rubbing against the surface of the round steel bar, which causes a problem of damaging the surface of the round steel bar.

As a means to solve this problem, Utility Model 49-127671
No. (Utility Model Publication No. 51-23024) has been disclosed. To explain this outline based on FIG. 6, a recessed hole 102 is bored at the tip of the bolt body 101, a steel ball 103 is inserted deep into the recessed hole 102, and a presser is inserted so as to be in contact with the steel ball 103. 104 is inserted, and the presser 104 is supported by the support flange 105 on the inner edge of the tip opening of the bolt body 101.
The bolt body 101 maintains the same axis with respect to the bolt body 101 and is rotatable. Therefore, when tightening the bolt, presser 1 at the tip of the bolt
When 04 contacts the surface of the round steel bar, the rotation of the pusher 104 is prevented by the frictional resistance of the contact surface, and although the bolt body 101 rotates, the pusher 104 does not rotate, so the surface of the round steel bar is not scraped. It is.

[Problem that the invention attempts to solve]

However, in the above-mentioned prior art, the presser 104 can be inserted only from the opening edge of the tip of the recessed hole 102, so it is not easy to attach or replace the presser 104.
That is, in the prior art, in order to support the presser 104, after inserting the presser 104 into the recessed hole 102, a support collar 105 is created by press molding or the like, but with such a configuration, it is difficult to assemble the bolt. It requires a press machine and takes time to assemble.

If the support flange 105 is formed by bending in this way, firstly, it is not easy to remove the presser 104, and secondly, if the presser 104 is frequently attached and detached, the support flange 105 will be repeatedly bent, and eventually will break at the bend and become unusable.

[Means for solving problems]

Therefore, in the present invention, a through hole 5 is bored through the bolt body 1 in the axial direction. The female threaded portion 6 extends over the head side of the
A presser 7 consisting of a head 9 having approximately the same diameter as the through hole 5 and a tip 8 having approximately the same diameter as the narrow diameter portion 5a of the through hole 5 is rotatably inserted into the through hole 5. Then, the tip part 8 is made to protrude outside from the narrow diameter part 5a, the sphere 10 is brought into contact with the head 9 of the presser 7, and the screw shaft 11 is screwed into the female thread part 6 of the through hole 5. In particular, the problem is solved by enclosing the presser 7 and the sphere 10 in the through hole 5.

[Effect]

When the pusher 7 at the tip of the bolt comes into contact with the surface of the round steel bar when tightening the bolt B, since the pusher 7 is rotatable relative to the bolt body 1, the frictional resistance of the contact surface with the round steel bar causes the pusher 7 to Rotation is prevented, and although the bolt body 1 rotates, the presser 7 does not rotate, so that the surface of the round steel bar is not scraped.

Since the sphere 10 and the pusher 7 are enclosed in the through hole 5 by the screw shaft 11, the pusher 7 can be taken in and out from the head side of the bolt body 1, and the pusher 7 is easy to load and replace.

〔Example〕

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

The bolt body 1 has a hexagonal prism-shaped head 2, a neck 3 of an appropriate length, a threaded portion 4 carved on the outer periphery of the neck 3, and a through hole 5 that penetrates in the axial direction. It becomes. The through hole 5 has a narrow diameter portion 5a on the tip side of the bolt body 1, and further has a female threaded portion 6 extending from a substantially middle portion of the through hole 5 to the head 2 side of the bolt body 1.

The presser 7 to be loaded into the through hole 5 includes a tip portion 8 having approximately the same diameter as the narrow diameter portion 5a of the through hole 5, and a head portion 9 having approximately the same diameter as the through hole 5. The presser 7 is attached to the bolt body 1
The bolt is inserted into the through hole 5 from the head 2 side with the tip 8 first, and the tip 8 projects to the outside of the bolt body 1 through the narrow diameter portion 5a of the through hole 5. The head 9 and tip 8 of the presser 7 are cylindrical in shape and have the same diameter as the through hole 5 and the narrow diameter portion 5a, respectively, and are therefore rotatable within the through hole 5. Then, the sphere 10 is inserted into the through hole 5, and the screw shaft 11 is inserted into the female threaded portion 6 of the through hole 5.
The sphere 10 and the presser 7 are enclosed in the through hole 5 by screwing together the threaded portion 12 of the spherical body 10 and the presser 7. In addition,
The screw shaft 11 has a conical concave arc surface 13 at its tip, and the concave arc surface 13 holds the sphere 10 at the center. A hole 14 is provided.

Next, an example of use of the bolt B of the present invention will be explained.

Figures 4 and 5 illustrate the state in which two round steel bars are butted and temporarily fixed when welding the round steel bars. In this case, the support for holding the round steel bar is a pair of holders D, D provided at a distance on a support base C, and the holder D has bifurcated arms as shown in Fig. 5. The pieces E and E' are set upright, and a screw hole F into which the threaded part 4 of the bolt B is screwed is bored in one arm piece E, and the inner part of the other arm piece E' A contact portion H of round steel bar G is formed on the side surface.

Then, place the round steel bar G between the arm pieces E and E′, screw the bolt B into the screw hole F, and tighten it.
is fixed by pressing the bolt B against the abutting portion H of the arm piece E'.

At this time, the tip 8 of the pusher 7 of the bolt B protrudes, and the pusher 7 comes into contact with the surface of the round steel bar G. This pusher 7 is rotatable within the through hole 5, and since the sphere 10 is interposed between it and the bolt body 1, the frictional resistance between the two is extremely small. The rotation of the presser 7 is prevented by overcoming the frictional resistance caused by the contact between the surface of the presser and the tip of the presser 7, and as a result, the presser 7 moves only in the linear direction without rotating. Therefore, it is possible to fix the round steel bar G with the bolt B without cutting the surface thereof.

In addition, by forming the tip end surface of the tip part 8 of the presser 7 into a concentric uneven surface 8' as shown in FIG. 2, the contact area is reduced and the contact surface of the round steel bar G is not damaged. You can do it like this.

[Effect of idea]

As described above, since the bolt B of the present invention has a rotatable tip, it can be fixed without scraping the surface of the round steel bar G. from the head 2 side of the bolt body 1, and then insert it into the screw shaft 11.
Since it is sealed in the through hole 5 by
Bolts can be assembled without using processes such as pressing, making it extremely efficient. Furthermore, there is no risk of damage to the bolt body 1 no matter how many times the presser 7 and the sphere 10 are replaced, and the protruding length of the presser 7 can be easily adjusted by adjusting the screw shaft 11. , it is highly practical.

[Brief explanation of drawings]

The figures relate to one embodiment of the present invention, and Fig. 1 is an external perspective view, Fig. 2 is an exploded perspective view, Fig. 3 is a vertical sectional view, Fig. 4 is a front view showing an example of use, and Fig. 5 is a front view showing an example of use. The figure is a sectional view of the main part of the same as above, and FIG. 6 is a longitudinal sectional view showing the prior art. DESCRIPTION OF SYMBOLS 1...Bolt body, 2...Head, 5...Through hole, 5a...Small diameter hole, 6...Female thread part, 7...Press element, 8...Tip, 9...Head, 10... …sphere,
11...screw shaft, B...bolt.

Claims (1)

[Scope of utility model registration request] A through hole is bored through the bolt body in the axial direction, and the through hole has a small diameter portion on the tip side of the bolt body and forms a female thread portion extending from approximately the middle portion to the head side of the bolt body. A presser consisting of a head having approximately the same diameter as this through hole and a tip having approximately the same diameter as the narrow diameter portion of the through hole is rotatably inserted into the through hole and the tip is inserted into the narrow diameter portion. The presser and the sphere are sealed in the through hole by protruding outward from the through hole, bringing the sphere into contact with the head of the presser, and further screwing a screw shaft into the female threaded portion of the through hole. Bolt is characterized by the fact that it did.