JPH0590737U - Cable for signal transmission - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a signal transmission cable in which the sheath can be easily torn and stripped. [Configuration] A plurality of pairs of twisted pair wires 6 are twisted together to form a cable core 7. Also, the cable core 7
A lip cord 8 such as a polyester fiber string is vertically provided on the outer periphery of the, and a plastic sheath 9 is extrusion-coated on the lip cord 8. And lip code 8
Has a plastic sheath 9 for most of its cross section.
It is embedded inside, and a part of the surface is exposed to the inner peripheral surface of the sheath.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a signal transmission cable, and more particularly to a signal transmission cable in which a tear wire is provided and the tear of the sheath is easy.

[0002]

[Prior Art]

 Recently, for example, with some data (signal) transmission cables, the work of connecting the connector of the modular type connected to the terminal to the connector of the equipment housing has been carried out at the site after cable installation. It is often seen. Since such connection work is frequently performed, a lot of recent signal transmission cables are equipped with a lip cord (tear string) under the sheath to facilitate the stripping work of the sheath. ing. That is, as shown in FIG. 5, a lip cord 3 (tear string) such as a polyester fiber string is wound around or vertically attached to the outer circumference of a cable core 2 formed by twisting a plurality of pairs of insulating core wires 1. A signal transmission cable having a structure in which the plastic sheath 4 is covered with the signal transmission cable is used.

[0003]

[Problems to be solved by the device]

 However, in the conventional signal transmission cable having such a structure, as shown in FIG. 6, the position where the lip cord 3 comes into contact with the inner peripheral surface of the plastic sheath 4 when a force pulling the lip cord 3 and applying it outward is applied. The force is not concentrated at one point on the inner peripheral surface of the plastic sheath 4 because the plate shifts to the left and right or wobbles. Therefore, not only a large force is required for tearing the sheath, but also the tear cross section is not smooth. In particular, when the plastic sheath 4 is thick, the tearing and stripping of the sheath by the lip cord 3 has been a very laborious and difficult task.

The present invention has been made to solve such a problem, and an object thereof is to provide a signal transmission cable in which the sheath can be easily torn and peeled off.

[0005]

[Means for Solving the Problems]

 The signal transmission cable of the present invention comprises a wire core having a high tensile strength for sheath tearing, and a plastic sheath provided on the outer circumference of a cable core formed by twisting a plurality of pairs of core wires. In the cable, the high tensile strength wire is arranged along the length direction and is embedded in the inner peripheral surface of the plastic sheath so that a part of the surface thereof is exposed.

[0006]

[Action]

 In the signal transmission cable of the present invention, the high tensile strength wire for tearing the sheath disposed along the length direction is embedded in the inner peripheral surface of the plastic sheath so that a part of the surface is exposed. Therefore, the wall thickness of the plastic sheath is thinner than the other portions only in the linear portion in which the wire rod is embedded. Therefore, when this high tensile strength wire rod is pulled out and a force is applied, the force is easily concentrated on this linear portion, and the sheath can be easily torn. In addition, since the contact position of the wire on the inner peripheral surface of the sheath does not swing to the left or right, the force is concentrated on the contact part, so that the tear of the sheath is easy and the cross section of the sheath after tearing is also easy. Smooth and stable.

[0007]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of the signal transmission cable of the present invention, and FIG. 2 is an enlarged view of a portion A in FIG.

In the figure, reference numeral 5 indicates an insulating core wire in which an insulator such as polyethylene is provided on a conductor, and two or more pairs of the twisted wires 6 are twisted to form a pair. The cable core 7 is formed. On the outer circumference of such a cable core 7, a lip cord 8 having a high tensile strength such as a polyester fiber string is arranged (longitudinal) along the lengthwise direction, and on top of it, A plastic sheath 9 such as polyvinyl chloride is extrusion coated. Most of the cross section of the lip cord 8 is embedded in the plastic sheath 9, and a part of the surface is slightly exposed to the inner peripheral surface of the sheath.

The cable having such a structure can be continuously manufactured by partially changing the conventional sheath extrusion coating method. That is, in general, the extrusion coating of the cable sheath 9 is performed by a method in which a plastic material for coating is extruded in a pipe shape on the outer periphery of a material to be coated such as a cable core, and the cable of the embodiment is manufactured. In this case, as shown in FIG. 3, a nipple 11 in which a passage hole 10 for a lip cord is arranged is provided in a cable sheath extruder at the base of a pipe portion which is a passage for a plastic material. Then, as shown in FIG. 4, a method in which the lip cord 8 is inserted from the inside of the through hole 10 to the outside and the plastic material 12 is extruded and covered in a pipe shape on the outer periphery of the cable core 7 while being fitted thereto. Is taken. Incidentally, reference numeral 13 in the drawing indicates a die.

In the signal transmission cable of the embodiment thus configured, the lip cord 8 having high tensile strength is embedded in the inner peripheral surface of the plastic sheath 9 so that a part of the surface thereof is exposed. In the plastic sheath 9, only the linear portion along the length direction in which the lip cord 8 is embedded has a wall thickness extremely thinner than the other portions. When the pressure is applied, the force tends to concentrate on the burying line of the plastic sheath 9. Further, the contact position of the lip cord 8 on the inner peripheral surface of the plastic sheath 9 does not shift to the left or right or swing, and the force concentrates on the contact portion. Therefore, the plastic sheath 9 can be easily torn, and the cross section of the sheath after being torn is smooth and stable.

In a shielded cable in which a shield layer is provided on the outside of the cable core, a drain wire made of a conductive metal is generally in contact with the shield layer in order to ground the shield layer at a terminal portion or the like. Although it is provided inside the plastic sheath, this drain wire can also be used as a wire for tearing the sheath. That is, the same effect as the present invention can be obtained by embedding the drain wire in the inner peripheral surface of the plastic sheath so that only a part of the surface thereof is exposed.

Is obtained.

[0013]

[Effect of the device]

 As described above, according to the signal transmission cable of the present invention, the high tensile strength wire rod such as the lip cord is embedded in the inner peripheral surface of the plastic sheath so that a part of the surface thereof is exposed. By pulling out this wire and applying force, the sheath can be easily torn and stripped, and the torn sheath cross section is smooth and stable.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a signal transmission cable of the present invention.

FIG. 2 is an enlarged view showing a portion A in FIG.

FIG. 3 is a perspective view showing a nipple of a sheath extruder used for manufacturing the signal transmission cable of the embodiment.

FIG. 4 is a diagram illustrating a method of manufacturing a signal transmission cable according to an embodiment.
FIG. 6 is a vertical cross-sectional view for explaining the extrusion process of the plastic sheath.

FIG. 5 is a cross-sectional view showing a conventional signal transmission cable.

FIG. 6 is a perspective view showing a state in which a sheath is torn by a lip cord in a conventional signal transmission cable.

[Explanation of symbols]

1, 5 ... Insulated core wire, 2, 7 ... Cable core, 3, 8 ... Lip cord, 4, 9 ... Plastic sheath, 6 ... Twisted wire, 10 ... Lip cord passage hole, 11 ... Nipple, 1
2 ... Plastic material.

Claims (1)

[Scope of utility model registration request] 1. A cable comprising a wire core having a high tensile strength for tearing a sheath disposed on the outer periphery of a cable core formed by twisting a plurality of pairs of core wires, and a plastic sheath provided on the wire. A cable for signal transmission, characterized in that a wire is arranged along the length direction and is embedded in the inner peripheral surface of the plastic sheath so that a part of the surface of the wire is exposed.