JPH0649816U - bolt - Google Patents

Abstract

(57) [Summary] [Purpose] With bolts used for connecting pipes of water, gas, etc., almost constant tightening torque and tightening axial force can always be obtained, and tightening work can be performed quickly. To provide bolts. [Structure] T is attached to the side of the incomplete thread of the shaft 12 of the bolt 10.
A head portion 14 having a shape, and a screw portion 18 of the shaft portion 12.
The reaction force receiving portion 16 was provided on the side through a notch portion 24 set so as to be broken by a predetermined tightening torque.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a bolt, and more particularly to a T-shaped bolt used for connecting pipes for water and gas.

[0002]

[Prior art]

 Water and gas are indispensable items for people's daily lives, and the pipes that supply them are important in public goods. Especially in gas piping, gas leakage from the connecting part may cause a serious accident, and it is necessary to tighten the bolts with an appropriate torque when connecting the parts with bolts. That is, if the tightening force of the bolt is weak, the nut may gradually loosen due to vibration, etc., and finally there is a risk that gas leakage may occur from the connection part of the pipe. On the other hand, if the tightening force of the bolt is too strong, an excessive axial force will be generated on the shaft of the bolt, especially on the screw. May be broken, and there is a risk of sudden gas leakage.

For this reason, when bolts are connected at the connection of pipes such as water and gas, a wrench with a ratchet that is normally used is used by combining a bolt having a T-shaped head and a hexagon nut. After pre-tightening by hand, the torque wrench was used to confirm whether the screws were tightened with a certain torque and to make the final tightening.

[0004]

[Problems to be solved by the device]

 However, in bolt connection, it is important to keep the bolt tightening axial force constant, but as shown in Fig. 3, the torque is adjusted by the speed at which the ratchet wrench or torque wrench is rotated (tightening speed). Since the coefficient value changes, even if a torque wrench was used to tighten with a constant torque, there was no guarantee that it would be tightened with the specified tightening axial force. In addition, it is not possible to confirm whether or not the tightening is properly performed by the general manual tightening using the nut. Therefore, if tightening is incomplete, there is a risk of gas leakage.

Further, it is difficult for a worker to control the rotation speed of the wrench in order to keep the bolt tightening axial force constant, which requires skill. Moreover, it is extremely inconvenient to check with a torque wrench after pre-tightening with a ratchet wrench, etc., and the labor required for such manual assembly, tightening, and inspection is great. It was a cause of prolonging construction on public roads.

[0006]

[Means for Solving the Problems]

 Therefore, the inventor of the present invention came to the present invention as a result of extensive research to solve the above problems. The gist of a bolt according to the present invention is that a T-shaped head having a width across flats of the shaft portion is provided on the incomplete screw portion side of the shaft portion having the screw portion, The reaction force receiving portion is provided on the threaded portion side of the portion via a notch portion set so as to be broken by a predetermined tightening torque.

[0007]

[Action]

 The bolt according to the present invention is provided with a T-shaped head, and a reaction force receiving portion is provided through a notch portion which is set so as to be broken by a predetermined tightening torque. Is fixed to a nut screwed into the threaded portion, and the nut is rotated at a constant speed. When the nut reaches a predetermined tightening torque, the tightening torque acts between the nut and the reaction force receiving portion, so that the notch part is broken by the tightening torque and the tightening by the nut is completed.

The rotation of the nut can be performed at a constant speed until the reaction force receiving portion is broken at the notch, and it is not necessary to tighten the nut while paying attention to the tightening torque. The nut can be tightened at speed. Therefore, the torque coefficient value can be made almost constant, and moreover, since the notch part is broken and a substantially constant tightening torque can be obtained, it is possible to tighten with a substantially constant tightening axial force.

[0009]

【Example】

 Next, an embodiment of the bolt according to the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, the bolt 10 includes a shaft portion 12, a head portion 14, and a reaction force receiving portion 16. The shaft portion 12 has a screw portion 18, and the screw portion 18 is formed with a screw having a predetermined pitch. A head portion 14 is formed at the end of the shaft portion 12 on the side of the incompletely threaded portion, and the head portion 14 has a two-sided surface 20 having a width across flats which is substantially the same as the diameter of the shaft portion 12. Further, it has a load receiving portion 22 that receives an axial load in the direction of its two faces 20, and has a T shape as a whole. The load receiving portion 22 has a substantially spherical surface and is formed so as to have a high surface load.

On the other hand, a reaction force receiving portion 16 is formed on the screw portion 18 side of the shaft portion 12 via a notch portion 24. The reaction force receiving portion 16 is a portion that receives the reaction force of the rotational force applied to the nut 28 screwed into the screw portion 18, and the bolt 10 is fastened by the action reaction between the nut 28 and the reaction force receiving portion 16. To be done. Therefore, the reaction force receiving portion 16 is configured to receive the reaction force of the nut 28, and has a 12-point shape in this embodiment. The reaction force received by the reaction force receiving portion 16 is applied to the shaft portion 12 as a torque, and the torque is formed in a V-groove shape and concentrates the reaction force on the notch portion 24 having the smallest cross-sectional area. The notch portion 24 has a cross-sectional area and hardness set so as to be broken by a predetermined tightening torque, and when the notch portion 24 is broken and the reaction force receiving portion 16 is disconnected, the bolt 10 is predetermined. It is designed so that it can be confirmed that it has been tightened with the tightening torque of.

As shown in FIG. 2, the bolt 10 having such a structure is provided in a bolt insertion hole of a flange portion 32 integrally formed at one end of a pipe 30 such as gas or water and a flange portion 36 of a push ring 34. The shaft portion 12 is inserted through the provided bolt insertion hole, and the nut 28 is screwed into the screw portion 18. On the flange portion 32 side of the pipe 30, a part of the other end of the other connected pipe 38 is inserted, and between the other end of the pipe 38 and the inner diameter portion of the inserted pipe 30. By interposing one or a plurality of seal members 40 and pressing the seal member 40 with a push ring 34, both pipes 30 and 38 are connected to each other and both are sealed from gas leakage. Therefore, the pipes 30 and 38 are fastened by tightening the nut 28 with the bolt 10 inserted between the flange portion 32 of the pipe 30 and the flange portion 36 of the push ring 34.

To tighten the nut 28, the reaction force receiving portion 16 of the bolt 10 is fixed by, for example, an electric wrench having a planetary gear mechanism, and the nut 28 moves at a constant speed with respect to the reaction force receiving portion 16. Can be rotated with. When the nut 28 is tightened and reaches a certain tightening torque, the tightening torque is applied between the nut 28 and the reaction force receiving portion 16, the notch portion 24 is broken, and the reaction force receiving portion 16 is broken. Is separated.

Since the tightening of the nut 28 is stopped by the breakage of the notch portion 24 in this manner, the bolt 10 is always tightened with a constant tightening torque. Here, since the electric wrench is rotated at a constant speed, the torque coefficient value becomes substantially constant, so that the bolt 10 obtains a substantially constant tightening axial force, and the connecting portions of the pipes 30 and 38 are Securely tightened. Further, since the completion of tightening can be visually confirmed by the breakage of the reaction force receiving portion 16, it is not necessary to inspect the bolts 10 one by one after tightening them with a torque wrench, etc. Is greatly improved. Furthermore, in the tightening work, by using an electric wrench, the reaction force due to the tightening is not transmitted to the worker, so the labor is greatly reduced, the workability is improved, and the inspection work is shortened. The construction period can be significantly shortened, and the time to close public roads can be greatly shortened.

Although the embodiments of the bolt according to the present invention have been described in detail with reference to the drawings, the present invention is not limited to the above-described embodiments.

For example, the notch portion of the bolt according to the present invention can change the torque value at which it breaks depending on its minimum cross-sectional area, quenching hardness, shape, etc., and tightening can be performed by setting these conditions variously. The torque can be set. Also, the shape of the reaction force receiving portion is not limited to 12 points of a hexagonal shape having the same size and being coaxially displaced by 30 °, and it may be simply formed as a hexagonal shape. Any shape that can fix the Further, it goes without saying that the material of the bolt according to the present invention is not particularly limited.

In addition, the bolt according to the present invention may be used for directly joining the flange portions of the pipes, and the application is not particularly limited. For example, the present invention is within a range not departing from the gist thereof. The present invention can be implemented with various improvements, modifications, and variations based on the knowledge of those skilled in the art.

[0018]

[Effect of device]

 Since the bolt according to the present invention is configured with the T-shaped head, the head can be arranged in a narrow space such as a flange portion integrally formed with the pipe. Further, since the bolt according to the present invention is configured such that the reaction force receiving portion is provided on the screw side of the shaft portion through the notch portion set so as to be broken by a predetermined tightening torque, the reaction force receiving portion is formed. Part is fixed to the nut screwed to the screw part, and the nut is rotated and tightened, and when the notch part breaks, it is guaranteed that the bolt and nut are tightened with the specified tightening torque. . Furthermore, by tightening the nut at a constant rotation speed with an electric wrench, the torque coefficient value can be made almost constant, and the tightening axial force of the tightened bolt can be made to correspond to the set tightening torque. Can be stabilized at a predetermined value. Therefore, when bolts are used to connect the connections of pipes for water, gas, etc. using the bolt according to the present invention, the bolts can always be tightened with a tightening axial force that is within a stable and appropriate range. It is possible to prevent accidents of water leaks and gas leaks from the connection part due to improper force.

Further, since the bolt according to the present invention guarantees that it is tightened with a predetermined tightening torque by breaking at the notch, it is possible to visually check the presence or absence of the reaction force receiving portion. By doing so, it is possible to confirm that the screws are tightened with the specified tightening torque, and safety is greatly improved. Furthermore, since it is not necessary to use a torque wrench to tighten the bolts, workability is greatly improved. Moreover, bolt tightening work can be performed quickly using an electric wrench, etc., which not only improves workability but also reduces labor. Therefore, gas and water pipes are often dug up on public roads, but the work period can be shortened due to improvements in workability and the time taken to close roads can be shortened. The present invention has an excellent effect.

[Brief description of drawings]

1A and 1B are views showing an embodiment of a bolt according to the present invention, in which FIG. 1A is a front view, FIG. 1B is a plan view, FIG. 1C is a left side view, and FIG. d) is a right side view.

FIG. 2 is a cross-sectional view of main parts for explaining an example of use of the bolt shown in FIG.

FIG. 3 is a diagram showing a relationship between a nut tightening speed and a torque coefficient value.

[Explanation of symbols]

 10: Bolt 12: Shaft part 14: Head part 16: Reaction force receiving part 18: Screw part 24: Notch part 28: Nut

Claims (1)

[Scope of utility model registration request] 1. A T-shaped head having a width across flats of substantially the same width as the shaft portion is provided on the side of the incomplete screw portion of the shaft portion having the screw portion, and a predetermined portion is provided on the screw portion side of the shaft portion. A bolt characterized in that a reaction force receiving portion is provided through a notch portion set so as to be broken by a tightening torque.