JPH0338897Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" This invention relates to tape electric wires, and in particular to bend-resistant electric wires for transmitting signals to print heads of printers and the like.

``Prior art and its problems'' Conventionally, as this type of tape electric wire, the tape electric wire shown in FIGS. 4 and 5 is known, and the tape electric wire A shown in these figures consists of multiple parallel wires. The conductors 1, 1, . . . are covered with a plastic insulator 2, and the whole is formed into a band shape.

In the above-mentioned tape electric wire A, when the central portion of the wire is bent, as shown in FIG _. However, a tensile strain ε ₂ is generated on the outside 2b of the plastic insulator 2.

"Problem to be solved by the invention" By the way, in the tape electric wire A described above, when its bending radius r is large, the compressive strain ε ₁ and the tensile strain ε ₂ have the magnitudes ε ₁ =t/2r, ε ₂ = t/2r t: Thickness of the tape wire r: Represented by the bending radius of the tape wire, as a result, the neutral line M should be
are arranged on the axis of the conductors 1, 1, .

However, this formula is applied only when the bending radius r of the tape electric wire A is large, and is not applied when the bending radius becomes extremely small. As a result, as shown in FIG. 6, when the tape wire A is used for connection between the printer main body 3 and the print head 4 and the pulling operation of the tape wire A is frequently repeated, the bending radius of the tape wire A ( code r
) becomes extremely small, and the neutral line at which the strain becomes 0 is not necessarily located above the conductors 1, 1,..., which causes the problem that fatigue and breakage of the conductors 1, 1,... are likely to occur. It was hot.

"Means for Solving the Problems" This idea was made in view of the above circumstances, and its purpose is to obtain a tape electric wire in which the neutral line at which the strain becomes 0 is located near the axis of the conductor. In order to achieve this purpose, in a tape electric wire made of a plurality of parallel conductors covered with a plastic insulator and formed into a band shape as a whole, the conductors are placed closer to the surface facing inward when bent. I try to do that.

``Example'' Below, examples of this invention are shown in Figures 1 to 3.
This will be explained with reference to the figures.

In these figures, reference numeral B indicates a tape electric wire (flexible electric wire). This tape electric wire B is formed by covering a plurality of parallel rectangular conductors 11, 11, . . . (conductors) with a plastic insulator 12, and forming the whole into a band shape.

The rectangular conductors 11, 11, . . . of the tape electric wire B
As shown in FIGS. 2 and 3, its axis N is located slightly below the center of the plastic insulator 12. That is, the rectangular conductor 11,
11, . . . are arranged close to the surface 12' on the inward side when bent, and when the tape electric wire B is bent in the direction shown by the arrow, the neutral line is such that the strain is 0, so that the flat conductor 11, 11 , . . . With this, the rectangular conductor 1
plastic insulator 12 covering 1, 11...
is a rectangular conductor 1 as shown by symbols t ₁ and t ₂ in Fig. 2.
The lower thickness of 1, 11, . . . is smaller than the upper thickness.

In the tape electric wire B configured as described above, the rectangular conductors 11, 11, ... are connected to the plastic insulator 12.
Since it is placed close to one side 12' of the plastic insulator 12', when the center part is bent as shown by the arrow in FIG.
The rectangular conductor 11,
11,... substantially coincides with the axis N of . As a result, in the tape electric wire B, the strain near the axis of the rectangular conductors 11, 11, .
Fatigue of the rectangular conductors 11, 11, ... is less likely to occur,
This makes it difficult for the rectangular conductors 11, 11, . . . to be cut.

In addition, in the above example, a rectangular conductor tape electric wire was used, but it is not necessarily limited to this, and round conductor tape electric wire, stranded conductor tape electric wire, FPC
Electric wires such as conductor tape electric wires, round conductor flat cables, twisted conductor tape electric wires, etc. may be used.

"Effects of the invention" As explained in detail above, according to this invention, the axis of the conductor is placed closer to the inner surface when bent, so the strain near the conductor becomes zero when it is bent. Due to
This has the effect that fatigue of the conductor is less likely to occur and breakage of the conductor is prevented.

[Brief explanation of drawings]

Figures 1 to 3 are diagrams showing the structure of the bendable electric wire according to the present invention, and Figure 1 is the overall plan view;
Fig. 2 is a lateral side view, Fig. 3 is a longitudinal cross-sectional view of the bend-resistant electric wire when it is bent, and Figs. 4 and 5 are views showing a conventional tape electric wire, and Fig. 4 is its lateral side. 5 is a longitudinal sectional view of the tape electric wire when it is bent, and FIG. 6 is a diagram showing the connection of the tape electric wire between the printer main body and the printing head. 11... Rectangular conductor (conductor), 12... Plastic insulator, B... Tape wire (bending resistant wire).

Claims (1)

[Scope of utility model registration request] A bend-resistant electric wire formed by covering a plurality of parallel conductors 11 with a plastic insulator 12 and forming the whole into a band shape, characterized in that the conductors are arranged close to a surface facing inward when bent. Flexible wire.