JPS6115649B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for suspending a cable made of a plurality of twisted single-core cables, such as a triplex type cable.

Conventionally, this type of cable was made by placing a braided wire rope, such as a cable grip, over the cable and tightening it, relying on the strength of the cable sheath to support the weight of the cable.

However, in this case, although it shows sufficient performance for short periods of time, such as during construction such as lifting cables, there are concerns about the suspension performance for long periods of time or in high heat or low temperature atmosphere.

In addition, in order to tighten the cable sheath, a certain length is required, and for example, when taking out a branch on a suspended floor, there are cases where the cable sheath is dimensionally limited.

On the other hand, in the case of a single-core cable, the conductor is compressed and fixed using a compression clamp, and the upper part is supported at one point via an insulator. Wake up,
In addition, when compressing one conductor at a time, an unbalance occurred in the length between each phase, and the entire cable load was applied to one conductor, causing performance problems.

The present invention has been made for the purpose of solving the above-mentioned drawbacks of the prior art and providing a novel method for suspending twisted cables that can maintain the gripping force of the suspension part semi-permanently. However, when installing a twisted cable vertically, the conductors at the upper end of the cable are each crimped and fixed with a clamp, and each clamp is further connected to a length adjustment bolt through an insulating support. The length adjustment bolts for each conductor are passed through the hanging bracket and tightened with nuts from the top and bottom of the hanging bracket to be collectively fixed to the hanging bracket. A method for suspending a twisted cable is characterized in that the load applied to each conductor is balanced by adjusting the length of a hanging fitting by inserting a nut into the cable.

Next, an embodiment of the method of the present invention will be further described with reference to the accompanying drawings.

In the figure, reference numeral 1 indicates a plurality of twisted single-core cables, and the conductors 2, each of which has been stripped at its upper end, are compressed and connected by clamps 3.

Each clamp 3 is further connected and fixed to a length adjustment bolt 5a via an insulator 4.

Length adjustment bolts 5a for each of these cables
are passed through the hanging fittings 6, and the hanging fittings 6
is fixed to the hanging fitting 6 by tightening nuts 5b, 5b from above and below.

In this way, since a plurality of conductors 2 are each clamped 3 and suspended, an unbalance in length occurs between each cable.
The length can be adjusted by adjusting the mounting position of the length adjustment bolt 5a with respect to the suspension fitting 6 by inserting the screw, and then each cable conductor 2
It is possible to balance the load on the

The insulator 4 is for insulating the clamp 3 and the hanging fitting 6, and is made of synthetic resin or porcelain.

Both ends are fitted with embedded fittings or cement attachment fittings for fixing.When suspending cable 1, the full load of cable 1 will be applied, so use one with sufficiently high tensile strength. There is a need to.

For example, embedding metal fitting for M8 bolt, embedding length 12mm
In this case, it has been experimentally determined that a synthetic resin insulator has a tensile load of approximately 900 kg.

Normally, the maximum power supply line for apartments, condominiums, etc. is 600V CV-T3 x ^325mm2 , and the vertical hanging length is about 40m, so the total load is 400Kg.
becomes.

Each insulator mentioned above weighs 900 kg, so if it has three cores, three pieces are used, resulting in a breaking load of 2700 kg, and the safety factor is 6.75.

For the clamp and insulator 4, it is appropriate to use tape wrapping, a molded product of vinyl chloride cover, a heat-shrinkable tube, or the like.

Suitable synthetic resins for the insulator 4 include epoxy resin, phenol resin, plastic, Bakelite, and glass fiber.

For the clamp 3, in addition to hexagonal compression and circular compression, a soldering method may also be considered, but if the load is large, the compression method is preferable.

The strength of conventional suspension parts is that the sheath breaks or slips between the sheath and the cable grip occur under a tensile load of about 1 to 1.5 tons, and it gets worse under different outside and atmospheric temperature conditions. It may happen.

On the other hand, in the present invention, since each conductor is directly clamped, the smallest value among the breaking load of the conductor, the pull-out load of the compressed part, and the tensile load of the insulator can be said to be the load capacity.

Incidentally, in the case of a copper conductor with a cross-sectional area of 325mm ² , it is 20Kg/mm ²
×325mm ² ×3 = 19500Kg.

It has been experimentally determined that the pull-out load of the compressed portion is greater than the conductor breaking load if the surface area of the compressed portion is at least six times the cross-sectional area of the conductor.

The strength of the insulator is 2700Kg, and the M8 bolt has a screw length of 10mm and is approximately 3000Kg.

As is clear from the above, the load capacity of the present invention is several times better than that of the conventional suspension part.

In addition, the length of the suspension part, which conventionally required 500 mm or more, can now be less than half the length, which has the advantage that branching specifications for the suspension floor can be determined without being constrained by the length of the suspension part. There is also.

Furthermore, by distributing the cable load to the insulating support of each conductor and fixing them all at once to a strong hanging metal fitting, the tensile strength is maintained high, and the insulating support of each conductor is connected to the hanging metal fitting. are separately interposed via length adjustment bolts, ensuring a large insulation creepage distance by taking advantage of the length and thickness of each insulator, making it safe not only mechanically but also electrically. Another advantage is that it can be hung with high stability.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one embodiment of a cable line constructed according to the present invention, and FIG. 2 is an enlarged explanatory diagram showing a suspension part thereof. 1: Cable, 2: Conductor, 3: Clamp, 4:
Insulator, 5a: Length adjustment bolt, 5b: Nut, 6: Hanging fitting, 7: Insulation processing part.

Claims (1)

[Claims] 1. When a twisted cable consisting of multiple cables twisted together is installed vertically, the conductors at the upper end of the cable are each crimped and fixed with a clamp, and each of the clamps is attached to an insulating support. The length adjustment bolts for each conductor are fixed together through the suspension fittings, and the length adjustment bolts for each conductor are passed through the hanging fittings and tightened with nuts from above and below the hanging fittings, thereby being fixed to the hanging fittings at once. A method for suspending a twisted cable, characterized in that the load applied to each conductor is balanced and suspended by adjusting the length of the suspension fitting by inserting a nut into each length adjustment bolt.