JPH0874827A - High strength bolt - Google Patents

Abstract

PURPOSE: To provide a high strength bolt which necessitates neither friction treatment nor rust removal in connection of connection members. CONSTITUTION: A number of uneven portions 20 are formed on a rear surface 12a of a flange-like head 12 formed on one end of a high strength bolt 10. The uneven portion is prepared by collecting small projections. By fastening, the rear surface 12a of the head 12 is in press contact with a connection member 16. A frictional coefficient therebetween is remarkably increased by the presence of the uneven portions 10, thereby co-rotation of the high strength bolt 10 is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-strength bolt which transmits stress by a bearing joint method with increased frictional force.

[0002]

2. Description of the Related Art In recent years, in building structures and civil engineering structures, the joint structure of steel members has been replaced by high-strength bolt joints instead of rivet joints because of problems such as noise, fire, and skill. There is. This high-strength bolted joint generally means frictional joint, but there are joint types called tensile joint and bearing joint. The high-strength bolt is entirely rust-proof (black skin) treated, and an electric wrench is usually used to tighten the high-strength bolt.

[0003]

However, in such a conventional high-strength bolt, due to the rustproofing treatment applied to the high-strength bolt, the bolt head that comes into contact with the joint member surface and the joint The coefficient of friction with the painted surface of the member is low (0.2
When tightening with a high torque electric wrench,
In many cases, slippage occurs between the head of the bolt and the surface of the joining member with which the head is locked, and co-rotation of the bolt occurs. Therefore, conventionally, it has been necessary to intentionally increase the friction coefficient by removing the black skin of the joining member surface by shot blasting or the like.

Therefore, in the conventional high-strength bolt, in order to avoid co-rotation, it is necessary to perform friction treatment on the joint member surface by shot blasting, and after the bolt tightening work is completed, rust removal of this unpainted portion, coating, etc. It took a lot of trouble and time because it was necessary to do extra work.

In view of the conventional problems, it is therefore an object of the present invention to provide a high-strength bolt which does not require friction treatment and rust removal of a joining member.

[0006]

In order to achieve such an object, the present invention has a collar-shaped head formed at one end and a threaded portion formed at the other end, so that a rust preventive treatment can be applied to the whole. In the high-strength bolt used, a large number of concave and convex portions are formed on the contact surface of the head with the joining member to increase the frictional force between the head and the joining member.

[0007]

In the high-strength bolt of the present invention having the above-described structure, since a large number of uneven portions are formed on the contact surface of the head with the joining member, the friction coefficient of the contact portion with the joining member is formed by these uneven portions. Can be significantly increased. Therefore, even if the joining member is coated, it is possible to prevent the high-strength bolt from rotating together when tightening.

[0008]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. 1 and 2 show an embodiment of a high-strength bolt according to the present invention, FIG. 1 is an overall front view, and FIG. 2 is an enlarged view of a main part of a head.

That is, in the high-strength bolt 10 of this embodiment, as shown in FIG. 1, a flange-shaped head 12 is formed at one end and a threaded portion for screwing a nut (not shown) at the other end. 14 is formed. The back surface 12a of the head portion 12 is adapted to come into contact with a joining member 16 shown by a two-dot chain line in the figure. Also,
The surface of the high-strength bolt 10 is entirely rust-proofed.

The high-strength bolt 10 of this embodiment is constructed as a torcia type, and a torque control portion 18 with a break neck 18a is integrally provided at the tip of the screw portion 14 so as to project. Then, the torque control unit 1
8, the nut rotation torque of the electric wrench is controlled, and the tightening force can be controlled by the breaking torque of the break neck 18a.

Here, in this embodiment, a large number of concave and convex portions 20 are formed on the back surface 12a of the head portion 12. As shown in FIG. 2, the uneven portion 20 is integrally provided on the head 12 as an assembly of small protrusions 20 a.
The tip of the contact member is brought into contact with the joining member 16. Of course, the surface of the uneven portion 20 is also subjected to rust prevention treatment.

The high-strength bolt 1 of the present embodiment having the above-mentioned structure
In No. 0, when joining the joining members 16 and 16a to each other, the high-strength bolt 10 is inserted through the joining members 16 and 16a, and the nut 22 is screwed into the screw portion 14 and tightened. By this tightening, the back surface 1 of the head 12
2a is gradually pressed against the joining member 16. At this time, since a large number of uneven portions 20 are formed on the back surface 12a of the head 12, that is, the contact surface with the joining member 16, the uneven portions 20 greatly increase the friction coefficient with the joining member 16. be able to.

Therefore, even if the head portion 12 is rustproofed or the joint members 16 and 16a are further coated, the space between the head portion 12 and the joint member 16 is tightened when the high-strength bolt 10 is tightened. Can sufficiently secure the frictional force of the joining member 16, and further prevent the high-strength bolt 10 from rotating together when tightening with an electric wrench.
A sufficient tightening force of 16a can be secured. If the frictional force is still insufficient, it is sufficient to use the washer 24 having the uneven surface on the contact surface 24a with the joining member 16a.

As described above, in this embodiment, since the concavo-convex portion 20 is formed on the back surface 12a of the head 12, it is possible to prevent co-rotation when the high-strength bolt 10 is tightened. It is possible to eliminate the rubbing process and the extra work such as rust removal after the rubbing process. Therefore, the joining work of the joining members 16 and 16a can be greatly simplified, and the work can be speeded up and the labor can be saved.

[0015]

As described above, in the high-strength bolt of the present invention, since a large number of concave and convex portions are formed on the contact surface of the head with the joint member, the concave and convex portions make contact with the joint member. The coefficient of friction of can be significantly increased. Therefore, when tightening the high-strength bolts, it is possible to prevent the high-strength bolts from rotating together even if the entire coating process is performed, and to perform extra work such as friction treatment and rust removal on the joining members. It is not necessary to perform the above, and the work of joining the joining members can be greatly simplified, and the excellent effects that the work can be speeded up and the labor can be saved can be achieved.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a high-strength bolt of the present invention.

FIG. 2 is an enlarged view of a main part of an embodiment of the high-strength bolt of the present invention.

[Explanation of symbols]

 10 High-strength bolt 12 Head 12a Back surface (contact surface) 14 Threaded portion 16 and 16a Joining member 20 Uneven portion 24 Washer

Claims (1)

[Claims] 1. A high-strength bolt in which a flange-shaped head portion is formed at one end and a screw portion is formed at the other end, and a rust-proof treatment is applied to the entire joint of the head portion. A high-strength bolt characterized in that a large number of concavo-convex portions are formed on the contact surface thereof to increase the frictional force between the head and the joining member.