JPH0694019A - High strength bolt - Google Patents

Abstract

PURPOSE:To provide a high strength bolt available at a narrow space, by forming a weak part smaller than the cross section of a screw part, between the head part and protruded part of a bolt main body. CONSTITUTION:A protruded part 16, protruded in the right angle direction of the axis of a bolt main body 15, is formed between a screw part 12 to which a nut 11 is threadably attached, and a head part 14 with which a tool 13 such as a nut runner or a spanner is engaged; and a weak part 17 smaller than the cross section of the screw part 12 is formed between the head part 14 and protruded part 16 of the bolt main body 15. A high strength bolt is inserted in a bolt hole to threadably attach a nut 11 to the screw part 12, and is used by rotatingly fastening the head part 14 protruded on the inserted side by a normal nut runner 13 or a motor-driven wrench.

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 capable of controlling a tightening torque for uniformizing a tightening axial force.

[0002]

2. Description of the Related Art A conventional high-strength bolt 38 has a head portion 37.
Has a pin tail 35 protruding from the tip of a screw portion 36 on the opposite side of the screw portion 36, and a fracture groove 34 is formed between the screw portion 36 and the pin tail 35. The cross-sectional area of the fracture groove 34 is the cross-sectional area of the screw portion 36. Is smaller than. This high-strength bolt 38 is a bolt hole 32 formed in a building member 33 or the like.
It is used by inserting the screw part 36 into the nut and screwing the nut 31, and inserting the pin tail 35 into the inner sleeve 40 of the electric wrench (high-strength bolt tightening machine) and grasping it, and inserting the outer sleeve 41 into the nut 31. At that time, when the outer sleeve 41 is rotationally driven, the nut 31 is tightened.

This electric wrench has an inner sleeve 40.
Receives a reaction force from the outer sleeve 41, and when the tightening torque of the nut 31 reaches a certain torque, the inner sleeve 40 receives a reaction force to shear the breaking groove 34 and the pin tail 35.
As a result, the inner sleeve 40 is separated from the high-strength bolt 38, the reaction force that has been acting up to that point disappears, and the rotation of the outer sleeve 41 stops.

Therefore, the maximum tightening torque of the nut 31 is equalized to a constant torque when the pin tail 35 is cut off.

[0005]

In the conventional high-strength bolt 38, the nut 31 is rotated by an electric wrench on the opposite side to which the high-strength bolt 38 is inserted as described above.

By the way, in a building member such as a corner post or a T-shaped post 28 which is designed to be drawn to the outside of the outer peripheral beam 29, a high strength bolt is inserted into the bolt hole 32 from the inside of the corner post or the T-shaped post 28. In some cases, there is no space 30 for inserting 38, and in such a case, the pin tail 35 cannot be projected outward, and therefore the nut 31 cannot be turned and tightened by the electric wrench.

Therefore, in such a case, the high strength bolt 3
8 cannot be used, and the general bolt must be used.

However, for that purpose, a torque meter must be attached to the power source of the electric wrench to control the torque of the electric wrench, but such an operation complicates the nut tightening work.

Therefore, according to the present invention, a sufficient space 30 is provided on the side opposite to the side on which the nut 31 of the conventional high-strength bolt 38 is screwed.
The present invention seeks to provide a high strength bolt 18 that can be used even in the absence of the above.

[0010]

A high-strength bolt 18 according to the present invention includes a bolt main body 15 between a screw portion 12 to which a nut 11 is screwed and a head portion 14 which engages with a tool 13 such as a nut runner or a spanner. Has a projecting portion 16 protruding in a direction perpendicular to the axis of the, and a fragile portion 17 having a cross-sectional area smaller than that of the screw portion 12 is formed between the head portion 14 of the bolt body 15 and the projecting portion 16. It is characterized by that.

The high-strength bolt 18 is used by inserting it into the bolt hole 32, screwing the nut 11 into the screw portion 12, and rotating the head 14 protruding from the inserted side with a normal nut runner 13 or electric wrench. To be done.

In this case, when the head 14 is further rotated and torque is applied when the constant tightening axial force is reached, the bolt body 1
5 is sheared by the fragile portion 17 having a small cross-sectional area, and as a result, the head portion 14 is cut off and the torque by the nut runner 13 or the like is not transmitted to the bolt body 15.

Therefore, the nuts 11 are provided on the front and back of the bolt hole 32.
It is tightened by a constant tightening axial force acting between the protrusion 16 and the protrusion 16.

When removing the high-strength bolt 18, the nut 11 may be rotated and loosened like the conventional high-strength bolt 38. Therefore, it is not always necessary to rotate the protrusion 16.

Therefore, the peripheral edge of the protrusion 16 may be a hexagon which is easy to rotate like the nut 11 (FIG. 4), or a circular shape which cannot be rotated by the nut runner 13 (FIG. 5). As shown in the drawing, the shape of the peripheral edge of the protrusion 16 may be any shape as long as it projects in the direction perpendicular to the axis of the bolt body 15.

The fragile portion 17 has only to have a cross-sectional area smaller than that of the screw portion 12, and for that purpose, like the break groove 34 of the conventional high-strength bolt 38, a groove 19 is formed on the peripheral surface of the bolt body 15. May be formed so that the thickness A of the groove 19 is smaller than the thickness B of the screw portion 12, or a fragile portion 17 is formed by opening a through hole orthogonal to the axis of the bolt body 15.
The cross-sectional area at may be reduced.

[0017]

The high-strength bolt 18 according to the present invention is tightened with a constant tightening axial force as described above, and the tightening with the nut runner 13 or the like is performed on the side into which the high-strength bolt 18 is inserted. Therefore, it can be used even when there is no space 30 necessary to operate the nut runner 13 or the electric wrench on one side of the bolt hole 32, and a special electric wrench composed of an inner sleeve 40 and an outer sleeve 41, a torque meter, etc. are not necessary. As a result, the tightening work of high-strength bolts is rationalized.

[Brief description of drawings]

FIG. 1 is a side view of a high-strength bolt according to the present invention.

FIG. 2 is a sectional side view of a high-strength bolt according to the present invention.

FIG. 3 is a perspective view showing a usage state of the high-strength bolt according to the present invention.

FIG. 4 is a perspective view of a high-strength bolt according to the present invention.

FIG. 5 is a perspective view of a high-strength bolt according to the present invention.

FIG. 6 is a perspective view of a high-strength bolt according to the present invention.

FIG. 7 is a side view showing a usage state of the high-strength bolt according to the present invention.

FIG. 8 is a side view showing a usage state of a conventional high-strength bolt.

[Explanation of symbols]

 11 nut 12 screw part 13 nut runner 14 head part 15 bolt body 16 protrusion part 17 weak part 18 high-strength bolt 19 groove 28 corner post 29 outer beam 30 space 31 nut 32 bolt hole 33 building member 34 break groove 35 pin tail 36 screw part 37 Head 38 High-strength bolt 40 Inner sleeve 41 Outer sleeve

Claims (1)

[Claims] 1. A protrusion 16 protruding in a direction perpendicular to an axis of a bolt body 15 is provided between a screw portion 12 to which a nut 11 is screwed and a head portion 14 which engages with a tool 13 such as a nut runner or a spanner. However, the fragile portion 1 having a cross-sectional area smaller than the cross-sectional area of the screw portion 12 between the head portion 14 of the bolt body 15 and the protruding portion 16.
High-strength bolt characterized in that 7 is formed.