JPH07147113A - Curled cord - Google Patents

Abstract

PURPOSE:To provide softness and keep a spring property stably by using a large number of stranded thin wires of a copper alloy such as copper containing tin as a conductor. CONSTITUTION:A large number of stranded thin wires are used as a conductor. A conductor 1 with outer diameter 0.51mm prepared by stranding thirty element wires with diameter 0.88mm of copper containing, for example, a prescribed % of tin is coated with an insulating coating 2 of polyvinyl chloride resin composition with 0.2mm thickness to give an insulated electric cable. Then, four of the insulated electric cables are quad-stranded, a transversely rolled shield layer 3 consisting of fifty of element wires with diameter 0.08mm is formed in the outer side to make the outer diameter be 2.4mm and further an outer coating 4 with 0.25mm thickness of polyvinyl chloride resin composition is formed to obtain a shielded cable with outer diameter 2.9mm. The shielded cable is coiled densely on a round bar with diameter 20mm, the resulting body is heated at 120 deg.C-150 deg.C for 30 minutes to 1 hour, cooled in air, and then the coiled cord is reversely coiled to give a curled cord with 15cm length of the curled part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curl cord having a stable spring property.

[0002]

2. Description of the Related Art Curl cords are widely used in applications requiring a variable distance, such as connecting a telephone handset to a main body. Recently, the shielded wire is also curled. A vinyl chloride resin composition or a urethane resin composition is used as a material for the outer cover of the electric wire, and the curl processing is performed by winding the electric wire around a round bar having a predetermined diameter and heating and heat setting, It has elasticity.

[0003]

However, if the curl cord is frequently used in a stretched state, the spring property is gradually lost, and even if the external force is removed, the original length cannot be restored. On the other hand, if the spring property is to be made extremely strong, a large external force is required for stretching and it is inconvenient to handle.

[0004]

SUMMARY OF THE INVENTION The present invention has been made for the purpose of eliminating the drawbacks of the conventional curl cord and obtaining a curl cord which is flexible and has a stable spring property. The use of multiple thin wires of copper alloy wire such as tin-containing copper as the conductor is that the curl cord has flexibility and is effective for retaining the spring property. As the copper alloy wire, for example, copper 99.1 to 9
Copper containing tin having a component ratio of 9.8% and tin 0.9 to 0.2% is preferable, but other high elastic copper alloy wires can also be used. or,
A thin wire having a diameter of 0.1 mm or less is preferable.

As a constitution of the shielded wire as the curl cord, for example, one having four insulated electric wires formed by a quad, which is collectively shielded, and whose outside is covered with a sheath can be mentioned. In this case, it is effective that only the conductor of the insulated wire is made of copper alloy, but the conductor of the shield layer can also be made of copper alloy. Although the center from the quad may be a void, it is also effective to provide an interposition having a predetermined size, for example, 0.4 times the outer diameter of the insulated wire, and using a highly elastic material for this interposition. is there. The material used for the interposition may be a copper alloy similar to that used for the conductor, but it does not need to be a copper alloy because it does not require conductivity, and may be another highly elastic metal or plastic.

[0006]

EXAMPLE Copper 99.7-99.8%, tin 0.2-0.3
% Of copper with tin in composition ratio of 0.08 mmφ
A polyvinyl chloride resin composition having a thickness of 0.20 mm was coated on a conductor made of a book and having an outer diameter of 0.51 mmφ to prepare an insulated wire. This insulated electric wire is put into a quad, and a shield layer of 50 wound wires of 0.08 mmφ is provided on the outer side of the quadruple to have an outer diameter of 2.4 mmφ. A 25 mm thick jacket was provided to create a shielded wire with an outer diameter of 2.9 mmφ. This shield wire is tightly wrapped around a 20 mmφ round bar,
After heating at 30 ° C. to 150 ° C. for 30 minutes to 1 hour and cooling in air, the wound cord was inverted to form a curl cord having a curl length of 15 cm.

[0007]

EFFECTS OF THE INVENTION The curl cord described in the examples (curl length 15 cm) was extended to a length of 1 m, and the restorability was examined. In the case of a curl cord having the same structure as that of the embodiment in which a normal annealed copper wire is used as a conductor, it is extended to a length of 1 m to 100 H
When it was held at r, the length did not return to the original length even if the external force was removed. However, in the case of the curl cord of the present invention, when the external force was released, the length returned to the original length in an extremely short time.

Although the tin-containing copper has been described in the embodiments, the spring property is similarly stably maintained even when a plurality of thin wires of another high-elasticity copper alloy such as phosphor bronze is used as a conductor. I was able to do it. It was also effective to maintain the spring property by using a highly elastic copper alloy for the conductor of the shield layer. Furthermore,
Providing an interposition of a highly elastic material having a diameter of about 0.4 times the outer diameter of the insulated wire at the center of the quad was also effective for maintaining the spring property. Further, by using a plurality of thin wires as the conductor, flexibility is imparted to the curl cord, and the external force when the curl cord is stretched does not have to be so large. Also, the same effect can be obtained by using thin wires for the shield layer.

[Brief description of drawings]

FIG. 1 shows a cross section of a curl cord of the present invention.

FIG. 2 shows another example of a cross section of a curl cord.

FIG. 3 shows the appearance of a curl cord when external force is not applied.

FIG. 4 shows the appearance of a curl cord when it is stretched by applying an external force in the direction of the arrow.

[Explanation of symbols]

 1: Conductor 2: Insulation coating 3: Shield layer 4: Outer sheath 5: Center interposition

Claims (3)

[Claims] 1. A spring, in which a plurality of insulated wires are provided with a collective shield layer, an outer circumference is applied to form a cord, and the whole cord is processed into a spiral shape excluding the end portion thereof to expand and contract in the length direction. A curl cord characterized by using, as a conductor, a multi-strand of fine copper alloy wire with high elasticity as a conductor. 2. The curl cord according to claim 1, wherein the bundled shield layer is formed by using a thin wire of a highly elastic copper alloy wire. 3. The curl cord according to claim 1, wherein a highly elastic material having a predetermined size is used as the center interposition.