JPH036127Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to an improved tension-resistant clamping type retaining clamp that is useful when anchoring overhead electric wires, particularly overhead ground wires, to a steel tower.

``Prior art'' For example, overhead ground wires are wires installed at the top of steel towers for lightning protection, and simple structures are made of galvanized steel stranded wires or aluminum-coated steel stranded wires. However, as the size of overhead power transmission lines has increased in recent years, the overhead ground wires have also been required to have appropriate conductivity, and multilayer structures have come to be used. This usually has a structure in which the inner layer is made of the zinc or aluminum coated steel wire to share the tension, and the outer layer is made of aluminum or aluminum alloy stranded wires twisted together to serve as a conductive member.

A typical example of such an overhead ground wire is an optical fiber overhead ground wire whose cross-sectional configuration is shown in FIG. This is made by placing a pipe 13 in the center of the electric wire, and twisting an inner layer 12 and an outer layer 11 around the outer periphery.An optical fiber 20 is housed inside the pipe 13, and it is intended to be used as a communication line. It is something to do.

In order to secure such an overhead ground wire to a steel tower, a retaining clamp is used that grips the wire by compressing or tightening the wire all at once.

``Problem that the invention aims to solve'' However, when the electric wires with the structure described above are held all at once from the outer periphery, since the outer layer is made of relatively soft aluminum or aluminum alloy,
In particular, in the case of a tightening type retaining clamp, when the clamp is tightened, the tightening force is not sufficiently transmitted to the inner layer, causing slippage between the inner layer and the outer layer, resulting in insufficient retaining force. . and again,
In the case of the optical fiber overhead ground wire, this tightening type retaining clamp is often used to protect the internal pipe, and there is a strong demand for a solution to this slippage.

"Means for Solving the Problems" In view of the above-mentioned circumstances, the present invention aims to provide a retaining clamp that can completely prevent the occurrence of the above-mentioned slippage. In a tightening-type retaining clamp that clamps an electric wire with metal fittings, tightens and fixes the wire, and holds it to a support, the metal fittings for holding the electric wire include the metal fitting part that holds only the inner layer of the twisted layer of the electric wire, and the outer layer. A retaining clamp for overhead electric wires, which is configured to have a gripping force of the metal fitting part that clamps only the inner layer is greater than the gripping force of the metal fitting part that clamps the outer layer. be.

"Function" Since the retaining clamp according to the present invention has the above-mentioned configuration, it has a wide area that firmly grips only the inner layer without a soft aluminum layer in the middle, so that the above-mentioned slipping does not occur. There isn't.

"Example" Examples will be explained below.

This embodiment takes as an example the case where the optical fiber overhead ground wire is held down.

In the present invention, the outer layer 11 and the inner layer 12 of the electric wire 10 are stripped in stages as shown in FIG. On the other hand, the retaining clamp is formed with a portion that grips only the inner layer of the stripped electric wire and a portion that grips the outer layer as well. That is,
In FIGS. 1 to 3, 1a is a groove configured to grip the outer layer as well, and 1b is a grip groove configured to grip only the inner layer. The retaining clamp according to the present invention has upper metal fittings 2 and 3 which are hinged to correspond to the lower metal fitting 1, and the upper metal fitting 2 corresponds to the respective gripping grooves and grips the outer layer 11 as well. , the upper metal fitting 3 is configured to grip only the inner layer 12. Numerals 4 and 5 are bolts for tightening the metal fittings. When gripping an electric wire with the retaining clamp according to the present invention, the outer layer 11 of the electric wire is stripped off in steps to expose the inner layer 12, as described above.
As shown in FIG. 1, the required metal fittings 2 and 3 are tightened to the respective stepped portions. 2nd and 3rd
The figures are sectional views showing the A-A cross section and the B-B cross section of FIG. 1, respectively, which have been tightened in this manner.

In the present invention, the contact area of the contact part 1b that grips the inner layer 12 is larger than the contact area of the contact part 1a with the electric wire of the part that grips the outer layer 11. With this configuration, a sufficient range of contact between the inner layer and the metal fitting that does not cause slippage can be ensured, and it is possible to effectively prevent the slippage seen in the conventional example.

Although the above embodiments have been described using an optical fiber overhead ground wire as an example, it goes without saying that the present invention is also applicable to ordinary overhead ground wires or small-sized power transmission lines.

"Effect of the invention" As mentioned above, the retaining clamp according to the invention has
In particular, the inner layer, which has a high strength, has a structure that allows it to be gripped with a stronger gripping force, so it is possible to achieve reliable retention without causing excessive deformation of the wire and without causing slippage, making it possible to achieve a secure hold on the wire without causing any slippage. It is particularly effective when applied to overhead ground wires, and has great industrial value.

[Brief explanation of the drawing]

Fig. 1 is an explanatory sectional view showing how the electric wire is held in place by the holding clamp according to the present invention;
The figure is a sectional view taken along the line A-A in Figure 1, and the same shown in Figure 3.
FIG. 1; Lower metal fitting, 2, 3; Upper metal fitting, 4, 5; Bolt, 10; Electric wire (overhead ground wire), 11; Outer layer, 1
2: Inner layer.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. In a tightening-type retaining clamp that clamps an electric wire with metal fittings and tightens and fixes the wire to a support, the metal fittings for holding the electric wire only touch the inner layer of the twisted layer of the electric wire. It is composed of a metal fitting part that clamps and a metal fitting part that clamps the outer layer as well, and is configured so that the gripping force of the metal fitting part that clamps the inner layer is greater than the gripping force of the metal fitting part that clamps the outer layer. A retaining clamp for optical fiber overhead ground wires. 2. In the optical fiber overhead ground wire retaining clamp described in claim 1 of the utility model registration claim,
This retaining clamp for an optical fiber overhead ground wire is configured such that the contact area of a metal part that clamps only the inner layer with the electric wire is larger than the contact area of the metal part that holds only the inner layer with the electric wire.