JPS5930004B2 - How to unbend rubber and plastic cables - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a method for straightening a rubber or plastic cable that is wound around a drum and has a bend, especially at the end thereof. This invention relates to a method for easily uncurling the ends of cables.

(Purpose of the Invention) As the conductor is coated with an insulator such as rubber or plastic, the thickness of the insulator becomes thicker and the diameter of the conductor inevitably increases as the voltage and capacity of rubber and plastic cables increase. The diameter of the cable is larger and the cable as a whole has a larger diameter.

On the other hand, for convenience in transportation and handling, the cable is wound around a drum of a size that matches the diameter of the cable, for example, in the case of a cross-linked polyethylene insulated cable, at an appropriate tension such as about 500 kg for a 154 KV class cable.

Therefore, due to this drum winding, it is inevitable that the cable will have curls throughout.

When installing the cable wound around the drum, it is necessary to straighten out the bends at the end of the cable created by winding the cable around the drum, and then assemble a termination box or a junction box there.

However, as mentioned above, as the thickness of the insulator becomes thicker and the diameter of the conductor becomes larger, it becomes extremely difficult to remove the bends at the end of the cable, which are caused by being wound around a drum. Therefore, there is a need for a method for easily unbending the cable end.

(Structure of the Invention) This invention was made based on the above-mentioned circumstances, and is characterized by peeling off the cable sheath at the end of a curved rubber or plastic cable to expose the shielding layer. After that, this end is fixed to a splint in a straight line, and a current is passed through the shielding layer at the end of the cable, and the Joule heat is used to heat and soften the rubber or plastic insulation layer, causing the cable insulation layer to bend. This method thermally removes the strain caused by curls and causes plastic deformation in a straight line.

Next, the method of the embodiment will be explained with reference to the drawings.
After peeling off the shield layer 4 to expose the shielding layer 4, the cable 1 is straightened by applying a splint 2 of about 2 m length for straightening the bend to this part and binding it with a fixing means 3 such as a binding wire or binding tape. Stretch it out and fix it.

Next, the ends of the conductor 5 are connected to both lengthwise ends of the exposed shielding layer 4 at the end of the cable 1 to form a closed loop, and a feed-through current transformer 6 is fitted into this closed loop to transfer the current to the end of the cable. Joule heat is generated there to soften the rubber or plastic insulator inside.

At that time, in order to prevent the insulator at the end of the cable and the exposed shielding layer 4 from being deformed such as unevenness or scratches by the splicing plate 2 or the fixing means 3, the end of the cable is sufficiently heated, for example, at 50°C for about 3 to 5 hours. Curved lines are removed.

Then, stop heating the core, release the binding, and attach plate 2.
Remove the cable to complete the bending of the cable end.

(Effects of the Invention) As explained above, according to the present invention, the sheath at the end of the cable is stripped off, the cable is straightened and fixed to the splint, and a current is passed through the shielding layer at the end of the cable to generate Joule heat. This is a very simple method that allows you to achieve good results.

Although stripping the sheath from the end of the cable may seem to complicate the process at first glance, since it is naturally necessary to remove the sheath from the end of the cable when assembling the termination box or junction box, this point should also be taken into consideration. When you think about it, the simplicity of this work is remarkable.

[Brief explanation of the drawing]

The drawings are explanatory diagrams showing one embodiment of the method of the present invention. 1... Cable, 2... Plate, 4...
...shielding layer at the end of the cable.

Claims (1)

[Claims] 1. After peeling off the cable sheath at the bent part of the rubber or plastic cable end to expose the shielding layer, fix this bent part in a straight line with a splint, and heat the cable by passing an electric current through the shielding layer. A method for unbending the end of a rubber or plastic cable, characterized by removing the splicing plate after heating has stopped.