JPS6021180Y2 - Tightening fittings for double-headed bolts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fastening fitting for a so-called double-headed bolt, a bolt having a fastening head connected to the bolt head through a stress concentration point.

When tightening a double-headed bolt (Fig. 1), when tightening torque is applied to head 2 with a tool such as a spanner or wrench, the tightening torque is transmitted to bolt head 1, that is, the entire bolt, via stress concentration point a. The bolt is screwed in, but if the applied torque exceeds the specified tightening torque, the stress concentration point a will break (Fig. 2), so it is possible to ensure that the bolt is tightened to the specified torque.

Such double-headed bolts are often used for clamping parts of overhead power transmission line spacers, dampers, etc. because they can provide appropriate bolt tightening force even when working at unstable heights.

However, the broken bolt head falls off and is lost after the bolt is tightened, making it impossible to confirm that the bolt has been tightened. It was not easy to redo the process, and in that case, there was a risk of a serious accident.

Furthermore, if the bolt head falls during construction, it will be subject to abnormal acceleration, which could cause personal injury to workers and other people below.

Particularly in recent years, overhead wires have become more common in urban areas and on roads, increasing the danger of -N9s falling on people and cars.

Furthermore, the deterioration of the surrounding environment due to scattering of bolt heads may also become a problem.

The present invention is intended to solve the above problems and will be explained below with reference to the drawings.

Figure 3 shows a ratchet type torque wrench to which the present invention has been applied.

3 is a handle, and 4 is a socket, which is detachably attached to one end of the handle 3 by a known method.

5 is a piece for preventing the broken head from falling off according to the present invention.

As shown in FIGS. 5 and 6, the falling-off prevention piece 5 is formed of metal or plastic into a substantially mouth-shaped shape, and has a mounting hole 6 formed at the top.

A mounting portion (not shown) at the top of the socket 4 is passed through the mounting hole 6 so as to be attached to the handle 3.

Reference numeral 7 denotes a narrow portion provided at the lower end of the falling-off prevention piece 5, which is bent into a dogleg shape in the illustrated embodiment.

In the example of FIG. 5, the side portions form part of a cylinder, and in the case of FIG. 6, the side portions are parallel planes.

By comparison, the one shown in FIG. 5 is more effective, but the one shown in FIG. 6 is easier to manufacture.

Figure 7 shows a box spanner to which the present invention has been applied.

In this case, the socket 4 is integral with the handle 8 of the box spanner.

Therefore, the falling-off prevention piece 5 is passed through the attachment hole 6 from the handle 8 side and is appropriately pressed with a stopper 9 to be attached.

Now, since the configuration is as described above, after screwing in the double-headed bolt A a little, if you press a torque wrench or box spanner with a falling-prevention piece toward the fastener 2, the narrow part 7 will expand immediately. and enters the center between the tightening head 2 and the bolt head 1, that is, the stress concentration point a.

Of course, the fastener 2 fits into the socket 4.

If the double-headed bolt A is screwed in in this state, it will break at the stress concentration point a with a predetermined torque.

When you lift the fastener, the upper part of the broken fastener 2 fits into the socket 4, and the lower edge is caught and held by the narrow part 7 of the fall prevention piece 5, so you can lift it by hand. can be removed.

If the hook piece 2a is formed in advance on the lower part of the tightening bolt 2, there is no need to worry about the socket engaging with the bolt head 1, and the engagement with the narrow width part 7 is more secure, and the effect of preventing the socket from falling off is reduced. Better.

According to the present invention, when the fastening of the double-headed bolt A is broken, it will not fall off, so by removing it by hand and submitting it to the administrator, the administrator can move it to the necessary location. It is possible to confirm that the screws are securely tightened, ensuring thorough tightening control.

In addition, since the side surface has no opening and has a narrow part, even if the fastener breaks, the broken fastener will be held by the narrow part of the socket and fall prevention piece and will never fall, ensuring safety. Not only is it suitable for use, but it is also suitable for environmental protection because it does not scatter around the workplace.

[Brief explanation of drawings]

Figure 1 shows a double-headed bolt, Figure 2 shows a state in which the tightening mechanism has been removed, Figure 3 is a perspective view of a ratchet-type torque wrench with the present invention applied, and Figure 4 shows a double-headed bolt when tightened. FIG. 5 is a front view of the state, FIG. 5 is a perspective view of the falling-off prevention piece, FIG. 6 is also a second embodiment, and FIG. 7 is a box spanner with a falling-off preventing device attached. In the diagram, A...Double-headed bolt, a...
・Stress concentration point, 1...Bolt head, 2...
...Tightening type, 3...Handle, 4...Socket, 5... Fall prevention piece, 6...Mounting hole 1.7... ... Narrow part, 8 ... Handle, 9
...Stopper.

Claims (1)

[Scope of utility model registration request] For holding the lower end of the tightening head 2, which is molded of metal or plastic and has a top mounting hole 6 on the outside of the socket 4 of a fastener such as a ratchet type torque wrench or box spanner, and has a broken bottom end. A fastening fitting for a double-headed bolt, characterized in that it has a narrow width part 7 and is equipped with a falling-off prevention piece 5 whose side part is formed into a substantially mouth shape.