JPH0443927Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to an undercarpet cable used in offices for interconnecting telephones or OA equipment, and the invention relates to an undercarpet cable that is used in offices for interconnecting telephones or OA equipment. When a branch wiring fitting is provided in the undercarpet cable, distortion occurring in the terminal portion during wiring can be suppressed to a minimum, and damage to the flexibility of the undercarpet cable can be reduced.

[Conventional technology]

A so-called local network is a system in which microcomputers and OA equipment installed in a carpeted room such as an office are connected to each other or to a common data bank, and the data held by each device is used mutually. It has been put into practical use.

Communication cables used for such purposes include a strip-shaped outer sheath made of insulating synthetic resin such as polyvinyl chloride, a lead wire, a core wire such as optical fiber, and a steel wire material for reinforcement. There is a structure with a buried structure (Publication No. 60-33309). The outline of this will be explained with reference to FIG.

The outer sheath 1 is a band-shaped member made of polyvinyl chloride, and is reinforced by a steel wire 5 buried in the center thereof. Communication optical fibers 4, 4 are embedded in this external sheath 1 on both sides of a wire 5,
Furthermore, lead wires 6, 6 are buried outside of it.

Grooves 2, 2 are provided on both upper and lower surfaces of the outer sheath 1, thereby preventing forces applied from above and below from acting on the communication optical fibers 4, 4.

Since the reinforcing wire 5 is connected to branch wiring fittings at both ends, it can be reinforced against the tensile force applied to the entire outer sheath 1, but the outer sheath made of insulating synthetic resin such as polyvinyl chloride and steel The wire rod 5 is in close contact with the outer sheath 1 but not bonded (or bonded) with the outer sheath 1, so the wire rod 5 moves relative to the outer sheath 1 in the torsional and longitudinal directions during wiring.

In this way, the reinforcing wire is fixed only at the connection part of the branch wiring fitting, so the relative relationship between the outer sheath 1 and the reinforcing wire 5 that occurs every time the undercarpet cable is bent during wiring work is reduced. Twisting and longitudinal deviations accumulate and are concentrated at the connection point between the wire 5 and the branch wiring fitting, resulting in large local deformations of the outer sheath 1 at the ends of the undercarpet cable. Furthermore, if the flexibility of the reinforcing wire is low, the flexibility of the undercarpet cable will be inhibited, and the undercarpet will not conform to the irregularities of the floor surface, making installation difficult.

[Problem that this invention attempts to solve]

The present invention solves the above problems by regulating the relative movement of the reinforcing wire and the outer sheath in both the torsional and longitudinal directions, and by improving the flexibility of the undercarpet cable. The objective is to minimize the damage to the

[Measures taken to solve the problem]

The measures taken in this invention to solve the above problems are as follows:
The reinforcing wire is a stranded wire made by twisting a large number of thin steel wires.

[Effect]

Since the reinforcing wire material is a so-called stranded wire made by twisting together a large number of thin strands, its outer peripheral surface has many spiral recesses along the strands, and the outer sheath is made of insulating synthetic resin such as polyvinyl chloride. When the reinforcing member is embedded in the reinforcing member, the outer sheath and the reinforcing member are joined with a portion of the outer sheath biting into the recess. Therefore, relative movement between the outer sheath and the reinforcing member in the torsional and longitudinal directions is restricted.

If the flexibility of the undercarpet cable is inhibited as a result of the reinforcing wire being combined with the outer sheath or due to the stiffness of the reinforcing wire itself, the practicality of the undercarpet cable becomes poor.
In the present invention, the flexibility of the stranded wire itself is limited to the above-mentioned one because the spiral groove on the outer peripheral surface of the stranded wire made by twisting a large number of wires is connected to a part of the outer sheath. This is much larger than the conventional reinforcing wire made of thick steel wire, and furthermore, since the connection between the stranded wire and the external sheath is not a rigid, integral connection, slight relative displacement in the longitudinal direction is allowed. The flexibility of the undercarpet cable is not particularly inhibited by the combination of the strands and the outer sheath.

〔Example〕

An embodiment of the present invention will be described with reference to FIG.

In this embodiment, the basic structure of the undercarpet cable is the same as that of the conventional example described above, but the two sides of the reinforcing wire embedded in the center of the outer sheath 11 are both sides of the reinforcing wire embedded in the center of the sheath 11. The core wire 13 of the communication cable is buried in the side.

The reinforcing wire is a steel wire 12a with a diameter of 0.3 to 0.5 mm.
The stranded wire 12 is made by twisting seven wires together, and a spiral groove 14 along the strands 12a is formed on the outer peripheral surface of the stranded wire 12. In the buried state, a part 11a of the outer sheath 11 bites into this spiral groove 14,
The two are thereby connected to each other. This bite 11a can move relative to the strands 12 along the helical groove 14, but the strands 12 can move longitudinally and torsionally relative to the bite of the outer sheath. It is practically impossible to move relative to each other.

The diameter and number of wires may be selected appropriately depending on the thickness and size of the outer sheath 11, but the larger the diameter of the wire, the larger the spiral groove 14, and the possibility of twisting the wire. Flexibility decreases. Furthermore, it is usually sufficient to use a stranded wire with seven strands, but if the stranded wire is too thin, its strength will decrease, and if the stranded wire is thick on top, the flexibility of the undercarpet cable will be reduced. is damaged.

Also, the greater the twisting strength, the smaller the pitch of the spiral grooves. The size of this pitch is not a particular problem in practice, and commercially available stranded wires are sufficient.

〔effect〕

As described above, the greatest effect of the present invention is that it solves the above problems and eliminates the problems of the prior art. Therefore, the present invention can prevent significant deformation at the end of the undercarpet cable due to accumulation of strain at the end during wiring work of the undercarpet cable.

Although it is not publicly known, by providing a large number of vertical grooves on the outer periphery of the reinforcing member, the relative movement of the reinforcing member in the torsional direction with respect to the outer sheath can be restricted. By providing the unevenness by processing or the like, relative movement of the reinforcing member in the torsional direction and the longitudinal direction with respect to the outer sheath can be restricted.

However, such means requires processing to form irregularities on the outer circumferential surface of one reinforcing wire.
Furthermore, the flexibility of the reinforcing wire itself is small, and since it is integrally connected to the external sheath in the torsional and longitudinal directions, the flexibility of the undercarpet cable is significantly inhibited compared to conventional ones. , making it extremely impractical. However, since the present invention uses stranded wire as a reinforcing material, there is no need to perform any special processing on the outer peripheral surface of the reinforcing member.Furthermore, the stranded wire itself as a reinforcing wire has extremely high flexibility, and the spiral shape of the outer peripheral surface Relative movement in the longitudinal and torsional directions is restricted (however, slight slippage in the helical direction is allowed) by coupling the groove (recess) of the outer sheath with a part of the outer sheath. Compared to the above, the flexibility of the undercarpet cable is not inhibited, but rather the flexibility of the undercarpet cable is improved, allowing the undercarpet cable to better adapt to the unevenness of the floor surface. It has the great advantage of being able to be installed.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention, and FIG. 2 is a perspective view of a conventional undercarpet cable. 11...Outer sheath, 12...Twisted wire, 12a...
...Bare wire, 13... Core wire of communication cable, 14...
spiral groove.

Claims (1)

[Scope of utility model registration request] A pair of core wires that serve as a signal transmission medium and a reinforcing steel wire that is located in the center between the pair of core wires and lined up parallel to the pair of core wires are made of belt-shaped polyvinyl chloride, etc. An undercarpet cable embedded in an external sheath made of insulating synthetic resin, characterized in that the reinforcing wire material is a stranded wire made by twisting together a large number of fine steel wires.