JPS6342404Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a spiral electric wire having a plurality of insulated core wires. For convenience of handling, the cord used to connect the VTR camera and the equipment may not be left straight, but may be required to be curled into a spiral shape. FIG. 1 is an external view of a typical spiral electric wire, showing an example of the wire curled in the Z direction.
Normally, this type of wire is used by stretching or contracting the spiral, but it is usually curled by reversing the direction of the spiral after it has been wound in a spiral and heat set to incorporate shrinkage stress. In this state, it is in a contracted state as shown in Figure 1, and even if it is stretched by applying an external force, it has properties similar to a spring, returning to its original state when the external force is removed. This type of electric wire is required to be difficult to break when repeatedly stretched and contracted, and that the force required for stretching is not too large. Therefore, there are ways to make the wire itself flexible by using the softest insulating material possible or making the conductor as thin as possible, but depending on the type of signal being transmitted by the wire, the conductor cannot be made very thin. Also, the number of core wires cannot be reduced, so there is a limit. Therefore, we investigated whether it was possible to somehow reduce the stretching force and increase the number of times of expansion and contraction even with the same conductor thickness and number of insulated core wires, and as a result, we found that the structure of the present invention could achieve the objectives. . This invention consists of twisting together a plurality of insulated core wires with an insulator applied to the conductor, and applying a plastic or rubber outer sheath to the outside of the wire. It is characterized by being curled. FIG. 2 shows an embodiment of the present invention, in which the electric wire 1 itself is curled in the Z direction, but the insulated core wires are twisted in the S direction as shown by dotted lines. Although not shown, the spiral curl direction may be the S direction, and the direction in which the insulated core wires are twisted may be the Z direction. Insulated core wires are generally made by simply applying one layer of insulation to a conductor, but a shielded insulated core wire may also be obtained by applying a shield on top of that and applying a second layer of insulation. Also, shielded insulated core wires and non-shielded insulated core wires may be combined and twisted together. Also, after twisting, a shield may be applied if necessary before applying the outer sheath. The curling process involves twisting multiple insulated core wires together.
A plastic or rubber sheath is applied to the outside of the electric wire, which is then spirally wrapped around a rod in the same direction as the twisted wire, heat set, and then twisted by reversing the threading direction. Curl it in a spiral in the opposite direction. Actually, there are 3 insulated core wires made of 7 x 0.14 mm annealed copper wires coated with 0.15 mm thick vinyl chloride, and 69 x 0.05 mm annealed copper wires coated with 0.14 mm thick vinyl chloride cores. 2 core wires, 7 wires x 0.1mm annealed copper wire with polyethylene insulation, 1 core insulated core wire with shield with shield and polyester tape wrapped on the outside, and 30 wires x 0.18mm annealed copper wire with polyethylene insulation. Then, twist the shielded insulated core wire with a shield and Teflon insulation on the outside in the right direction (S direction), and curl the PVC jacketed wire in the left direction (Z direction). This wire was processed to form Sample 1, and another electric wire having the same structure was processed to curl in the right direction (S direction) to form Sample 2. Using such a sample, we made a 34-turn spiral, stretched it to 6 times its length, and then shortened it to its original length. We investigated the number of times it took for the conductor or shield to break, as shown in Table 1. As can be seen, the number of expansions and contractions in Sample 1 was clearly greater than in Sample 2, and a large difference was observed. Also the same
Using a 34-turn spiral, the stretching force when stretched six times was investigated using a spring bakari. The results of the stretching force are shown in Table 2.
Sample 1 was clearly smaller than Sample 2, indicating that it could be stretched with less force.

【table】

[Table] As shown above, the reason why the twisting direction and the curling direction are reversed is that the number of expansions and contractions is higher than the twisting direction and the curling direction is the same, and the stretching force is smaller. This seems to be because the insulated core wires move in the direction of loosening, while those in the same direction move in the direction of tightening. As mentioned above, in the spiral electric wire of the present invention, the direction in which the insulated core wires are twisted and the direction in which the spirally curled wires are curled are reversed, so that the insulated core wires are not compressed against each other when stretched. Therefore, it has the advantage of not only being able to withstand a large number of stretching cycles and being reliable, but also having a small stretching force and excellent workability. In addition, the idea of reversing the curl direction and the twisting direction of the insulated core wire of the present invention is based on the idea that if the conductor is a stranded wire, the curl direction and the twisting direction of the conductor should be reversed. If the shield of the core wire is horizontally wound, the curl direction and the horizontally wound direction of the shield should be reversed.If the shield is applied horizontally to the twisted core all at once, the curl direction and the horizontally wound direction of the shield should be reversed. This can be applied to the idea that the direction should be reversed.

[Brief explanation of drawings]

FIG. 1 is an external view of a spiral electric wire, and FIG. 2 is an embodiment of the spiral electric wire of the present invention. 1 in the figure is an electric wire,
2 indicates an insulated core wire.

Claims (1)

[Scope of utility model registration request] An electric wire in which a plurality of insulated core wires each having an insulator applied to a conductor are twisted together and a plastic jacket or a rubber jacket is applied to the outside thereof is spirally curled in a direction opposite to the direction in which the insulated core wires are twisted. A spiral electric wire characterized by: