JPS6360609B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to overhead electric wires that are difficult to accumulate snow on. Typically, the outermost layer of an overhead wire is composed of a twisted metal wire layer. If snow accumulates on these overhead power lines,
The snow slides diagonally downward along the twisted grooves and adheres to the lower surface of the wire. If this phenomenon is repeated, the snow on the lower surface will increase and grow, eventually developing into a heavy pile of snow, which will damage the power lines and steel towers. Conventionally, overhead electric wires that prevented such increased snow accumulation were made by attaching multiple resin anti-snow rings to the overhead electric wires at intervals so that the rings intersected the twist grooves. Widely used systems are designed to stop the snow from sliding downward along the twisted grooves, and to allow the snow to fall before it develops into a large pile of snow. However, in this type of overhead power line, the resin anti-snow ring is fixedly attached to the outer surface of the overhead power line using adhesive, fusion, or tightening force, so it may be exposed to the harsh outdoor natural environment for a long period of time or exposed to heat cycles. When subjected to repeated vibrations or vibrations, a gap is created between the ring and the surface of the overhead wire, which has the disadvantage that the ring may shift laterally. The present invention improves these drawbacks. This will be explained based on an embodiment shown in FIGS. 1 and 2. In the figure, 1 indicates an overhead electric wire, for example, a steel-core aluminum stranded wire, and 2 indicates a resin anti-snow ring. The anti-snow ring 2 is attached to the overhead electric wire 1 at intervals along its longitudinal direction. . The anti-snow ring 2 is made of, for example, EVA resin.
The structure for attaching the anti-snow ring 2 to the overhead electric wire 1 is such that, as shown in FIG. The strands are located in the gap 6 between the layers and cover the strands that constitute the outermost twisted metal wire layer 3. The anti-snow ring 2 may be made of other materials, and a portion of the ring 2 may not cover the outermost twisted metal wire, but may simply be placed between the layers 3 and 4. . In addition, various methods can be adopted as means for positioning the anti-snow ring 2 between the outermost metal stranded wire layer 3 of the overhead electric wire 1 and the inner layer 4 thereof. A mold is installed on the outer periphery of the
A method of injection molding a thermoplastic resin or mixture into the mold at high temperature or pressure so that a portion of the resin or mixture reaches between the outermost metal stranded layer of the overhead wire and the inner layer thereof, and a pre-molded plastic. Wrap the tape (in this case, it is preferable to have a composite structure with a soft layer on the side of the wire) around the overhead wire, tighten it strongly using a mold, or tighten it while heating.
A portion may be located between the outermost metal strand layer and the inner layer thereof. Next, a specific example of a method of providing a resin anti-snow ring on an overhead electric wire by injection molding will be described with reference to FIG. First, as shown in FIG. 3, a steel-core aluminum stranded wire 1 having a nominal cross-sectional area of 330 mm ² is covered with a mold 5 so that a predetermined ring shape can be formed on the steel-core aluminum stranded wire 1. will be established. Next, a mixture of EVA resin, plasticizer, and tackifier was mixed at a temperature of 190°C and an injection pressure of 5.
When it was injected into the mold 5 at Kg/cm ² and solidified, a ring was formed with the structure shown in FIG. 2 (product of the present invention). In addition, when the temperature is set to 160°C in the above method, the resin does not reach between the outermost metal stranded wire layer and its inner layer, and the ring is formed on the surface of the outermost metal stranded wire layer. (Conventional product) Furthermore, the product of the present invention is injection molded at 190°C,
Both the conventional product injection molded at 160℃ and
After repeating the heat cycle in a temperature range of 60°C 500 times, the presence or absence of cracks in the rings was visually confirmed, and the resistance to shearing was measured for rings with no cracks. The shear resistance force was measured by measuring the force when the ring was sheared while rotating in the twisting direction of the outermost metal stranded wire layer of the steel-core aluminum stranded wire. At this time, the resistance strength of the product of the present invention and the conventional product was as shown in the following table.

[Table] As is clear from this table, in the product of the present invention, a part of the ring is located between the outermost metal stranded wire layer and the inner layer, so even if heat cycles are repeated, the ring can The resistance to lateral displacement is significantly improved compared to conventional products.

[Brief explanation of the drawing]

Fig. 1 is a front view showing an embodiment of the snow-resistant overhead electric wire of the present invention, Fig. 2 is an enlarged sectional view of the same essential part, and Fig. 3 explains an example of the method for manufacturing the snow-resistant overhead electric wire of the present invention. It is an explanatory diagram. 1...Overhead electric wire, 2...Resin anti-snow ring,
3...Outermost metal stranded wire layer, 4...Inner layer, 5...Mold.

Claims (1)

[Claims] 1. A snow-resistant overhead electric wire comprising a plurality of resin anti-snow rings attached at intervals to an overhead electric wire having at least a metal stranded wire layer on the outermost layer, the resin anti-snow rings A snow-resistant overhead electric wire is characterized in that a part of the wire is located between the outermost metal stranded wire layer of the overhead electric wire and the inner layer thereof.