JPH0429445Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a coiled cable that is easy to manufacture and whose conductor is hard to break due to repeated expansion and contraction.

[Conventional technology]

Conventional coil cables are generally made by twisting several cotton threads together to form a center interposition, around which multiple insulated core wires are wound in a spiral pattern, and around the outer periphery of these wires, a pressing tape, a shield layer, and a sheath are sequentially layered. For example, it is formed by winding a cable with a circular cross-section around a rod and heat-treating it.
59-17514, etc.).

[Problem that the invention attempts to solve]

However, in conventional coil cables, cotton yarn is used as the center interposition, so the thicker the cotton thread is used, the greater the variation in the outer diameter of the center interposition becomes. Therefore, after twisting, gaps often occur between the insulated core wires, or the insulated core wires often protrude from the stranding layer, and the workability of twisting the insulated core wires is poor.

In addition, since cotton yarn is a soft material, when it is processed into a coil, the insulated core wire located inside the coil tends to be partially buried in the center interposition. the result,
The inner insulated core wire may become loose or bent, which can easily cause poor appearance. Furthermore, if multiple insulated core wires are not twisted evenly around the center interlayer, or when several thick cotton threads are twisted together to form a center interlayer, some parts may fall into the valleys of the twisted cotton threads. If the coil is processed under such conditions, stress such as tension and twisting will be concentrated at specific points on the insulated core wire when the cable expands and contracts, causing the problem that the conductor is likely to break.

Therefore, in view of these problems of the prior art, the present invention aims to provide a coil cable in which insulated core wires can be easily twisted together, and which is less likely to cause poor appearance or disconnection of the conductor.

[Means for solving problems]

In order to achieve the above purpose, according to this invention,
In a coil cable made by twisting a plurality of insulated core wires around a central interposer, covering the outside with a sheath, and forming the coil cable into a spiral shape, the central interposer is made of thermoplastic resin, and a longitudinal wire is twisted around the core. It is characterized in that a plurality of support walls extending in the direction are provided radially.

[Effect]

In this invention, a resin molded body having a shape in which a plurality of support walls extending in the longitudinal direction is provided radially around the core is used as the center interposition of the coil cable, so the outer diameter of the center interposition is longer than the longitudinal direction. Since it is uniform in all directions and is moderately harder than the intervening material made of cotton thread, the insulated core wire can be wound efficiently and evenly. In addition to that,
When the coil is processed, the insulated core wires located inside the coil will not be buried in the center intervening space, and their arrangement will not be disturbed.This effectively prevents the insulated core wires from loosening or bending, improving the appearance. The incidence of defects is significantly reduced.

Furthermore, when twisting the insulated core wires around the center interposer, the plurality of grooves present in the center interpose extend parallel to the axis, and the insulated core wires are wound helically so as to cross them diagonally. Therefore, even after coil processing, the insulated core wire will not be buried in the center intervening groove. In addition, since the insulated core wires are always arranged evenly around the center interposition, stress concentration on specific insulated core wires caused by uneven twisting is eliminated, and the conductor of the insulated core wires is Less likely to break than wires.

Further, the center interposer made of thermoplastic resin is imparted with spring properties by heat treatment in the same manner as the sheath during coil molding. Since this central interposition has a plurality of support walls arranged radially and grooves exist between adjacent support walls, it is soft enough to be wrapped around a rod before heat treatment, and is soft enough to be wrapped around a rod before heat treatment. Since these supporting walls provide a large resistance to cable elongation, the resilience is high. Therefore, compared to conventional coiled cables that mainly rely on the elastic restoring force of the sheath, the springiness of the entire cable is significantly improved.

〔Example〕

FIG. 1 is a front view of the coil cable 1,
The cable 2 is formed into a spiral shape. The cable 2 extends longitudinally around the core 11, as shown in FIG. 2, which is an enlarged cross-sectional view.
A central interposer 10 having a shape in which support walls 12 are provided radially is disposed at the center, and insulated core wires 3 are twisted around the outside thereof. The outside of these parts is covered with a sheath 4.

This central interposer 10 is obtained by extrusion molding a thermoplastic resin such as soft polyvinyl chloride or polyurethane. In the example,
The grooves 13 between the supporting walls are arranged at intervals such that the insulated core wires 3 are not buried in the grooves 13 during the twisting process of the insulated core wires 3 or during the coil processing of the cable 2, that is, the width of the grooves 13 is set so that the width of the grooves 13 is such that the insulated core wires 3 are not buried in the grooves 13. Although it is set to be smaller than the outer diameter of the wire 3, in this invention, the insulated core wire 3 is wound diagonally across these grooves 13 and does not necessarily sink there. It is not necessary to make the width smaller than the outer diameter of the insulated core wire 3. This allows the insulated core wires 3 to be twisted evenly and in alignment around the center interposer 10, so that no appearance defects occur when the cable 2 is processed into a coil. Furthermore, since stress is not concentrated on a specific insulated core wire of the cable 2 during expansion and contraction, the conductor of each insulated core wire 3 is less likely to be disconnected than conventional ones, and durability is improved.

When the cable 2 having such an internal structure is formed into a coil, the center interposer 10 is soft due to the presence of a large number of grooves 13 and does not interfere with the winding operation when the cable 2 is wound helically. Since the central interposer 10 is made of the thermoplastic resin, it is imparted with spring properties by heat treatment, similar to the sheath 4, and the plurality of supporting walls 12 exhibit great resistance to expansion, especially after coil forming. , the restorability is improved, and the springiness of the coil cable 1 as a whole becomes extremely good.

In the embodiment, the number of centrally interposed support walls 12 is 10, but the number and the width of the groove between the support walls can be selected as appropriate depending on the number of insulated core wires used, etc. The shape of the support wall can also be changed arbitrarily.

[Effect of idea]

As explained above, the coiled cable of this invention uses a central intervening shape as described above, so that the work of twisting the insulated core wires can be done efficiently and evenly, and the inside of the coil can be twisted during coil processing. The insulated core wire will not loosen or bend. This eliminates appearance defects and greatly improves productivity.

Furthermore, since the insulated core wires are always properly aligned around the outer periphery of the center core without being buried in the surface of the center core, stress such as tension is not applied to a particular insulated core wire, and the conductor will not break. It becomes difficult.

In addition, since the center interposer is made of thermoplastic resin, when the cable is heat-treated and fixed in a spiral shape, the center interposer is also given springiness at the same time, and the presence of multiple supporting walls increases the elasticity. Because of this, it has the effect of greatly improving its restorability compared to conventional coiled cables that obtain elastic restoring force primarily through the sheath.

Note that this invention is not limited to the above embodiments, and it is of course possible to make various changes within the technical idea of this invention, such as increasing or decreasing the number of insulated core wires or providing a shield layer. .

[Brief explanation of drawings]

FIG. 1 is a front view showing an embodiment of a coiled cable according to this invention, and FIG. 2 is an enlarged cross-sectional view of the same cable. 1...Coil cable, 2...Cable, 3...
...Insulated core wire, 4...Sheath, 10...Center interposition,
11...Core body, 12...Supporting wall, 13...Groove.

Claims (1)

[Scope of utility model registration request] In a coil cable formed by twisting a plurality of insulated core wires around a central core, covering the outside with a sheath, and forming the wires into a spiral shape, the center core is made of thermoplastic resin, and a longitudinal core is formed around the core. A coil cable characterized in that a plurality of support walls extending in the direction are provided radially.