JPS633403B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a spring cable, and particularly to a method of manufacturing a spring cable using a metal spring.

Spring cables or cords are widely used for power and signal supply of moving or rotating parts. Particularly recently, cables for robots have been in high demand, and demands for miniaturization and use at high temperatures have become stronger.

Generally, the spring force of a spring cable utilizes restoring force due to compositional deformation of vinyl resin, urethane resin, or the like. For this reason, the thickness of the vinyl resin or urethane resin sheath cannot be made thinner in consideration of the spring force, which is a major obstacle to downsizing the spring cable.

In addition, the restoring force of these materials due to compositional deformation becomes extremely small at high temperatures, so sufficient care must be taken when using them at high temperatures of 40 degrees Celsius or higher.
Especially when used for vertical expansion and contraction, the upper part stretches too tightly and loses its restoring force, causing it to lose its function as a spring cable.

Therefore, when using a spring cable in high-temperature conditions or downsizing it, it is possible to use the spring force of a metal spring, but conventionally, the method of attaching a cable to a metal spring and winding it with tape has been used. Due to its high quality, a large amount of man-hours are spent on manufacturing it.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the prior art described above and to provide a method for manufacturing a spring cable using a metal spring at low cost and efficiently.

That is, the present invention forms a cable having a side groove into which a metal spring is inserted, and after or while inserting the metal spring into the side groove, the side groove is heated by a heat source prepared outside, and the metal spring is heated. This method of manufacturing a spring cable is characterized in that an electric current is passed through the metal spring itself to cause it to generate heat, thereby heating it from the inside as well, thereby heating and fusing the gutter.

Hereinafter, the present invention will be specifically described with reference to the drawings.

FIG. 1 is a sectional view showing two embodiments of a cable having a preformed metal spring insertion groove according to the present invention. After the required number of cores 3 are twisted together, they are extruded and covered with a plastic sheath 2 to form a cable. In this case, a groove 1 for inserting the metal spring is provided integrally with the plastic sheath of the cable and along the length of the cable (this is referred to as a side groove in the present invention). The structure of the side gutter may be a structure in which a plastic sheath protrudes from the cable body as shown in Figure 1A, or a structure in which a part of the sheath of the cable body is thickened as shown in Figure 1B. None, or a structure in which a groove is formed in that part may be used. Further, although FIG. 1 shows a structure in which a side gutter is provided at one location, the present invention is not limited to this, and a plurality of side gutter may be provided as necessary. The size of the groove is appropriately determined depending on the thickness of the metal spring to be inserted.

Next, a metal spring is inserted into the thus formed cable with side grooves 1 as shown in FIG.

FIG. 3 shows the structure of the spring cable after the metal spring 4 is inserted into the side groove.

Next, for example, a heater shaped like a pipe cut in half vertically is inserted inside the spring cable.
Expand the diameter of the heater and apply a little pressure to the cable to heat the open part of the gutter, and at the same time, apply current to the metal spring, causing the metal spring itself to generate heat, heating the gutter from the inside, and opening it. At the same time, the entire groove is brought into close contact with the metal spring 4 to complete the spring cable. There are various methods of heating and fusing the groove portion depending on the structure of the spring cable, the material of the sheath, etc., and the most suitable method may be used depending on each case.

In addition, the position of the side groove part may be configured so that it is located between the cable bodies as shown in FIG. It may be configured so that it is located in the side gutter outside of.

Further, in the above embodiment, an example was shown in which the side gutter portion is heated and fused after the metal spring is inserted into the side gutter.
In the present invention, the side gutter portion may be heat-fused while the metal spring is inserted into the side gutter.

The present invention has the following effects.

(1) Spring cables using metal springs can be manufactured efficiently at low cost.

(2) Even if metal springs are used, there is no need to attach them to the cables by wrapping them with tape as in the past.
A spring cable that can be used over a wide range of temperatures up to the rated temperature of the materials used, such as the sheath and insulator, can be manufactured by a simple method.

[Brief explanation of the drawing]

1A and 1B are cross-sectional views showing two embodiments of a cable having a pre-formed metal spring insertion groove according to the present invention; FIG. 2 is an explanatory view showing how a metal spring is inserted into the side groove; The figure is a partially sectional perspective view showing one embodiment of the spring cable after a metal spring is inserted, and FIGS. 4 and 5 are partially sectional perspective views showing other embodiments of the spring cable obtained by the present invention, respectively. . 1: Metal spring insertion groove, 2: Plastic sheath, 3: Core, 4: Metal spring.

Claims (1)

[Claims] 1. A cable having a side groove into which a metal spring is inserted is formed, and after or while inserting a metal spring into the side groove, the side groove is heated by a heat source prepared outside, and a current is passed through the metal spring to form a metal cable. A method for manufacturing a spring cable, characterized in that the spring itself is energized to generate heat and heated from the inside to heat and fuse the gutter.