Fiber-Optic Cable Layout That Prevents Core Wire Catching

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Solution Overview

Problem

Optical loss due to bending increases in optical fibers, particularly in non-slot structures, as the sheath and tension member are integrated, leading to a high risk of the optical fiber core wire being caught and further increasing loss during dismantling.

Innovation Solution

The tension members are disposed at positions sandwiching the cable core's axial center and warped outward, allowing the sheath to tear without catching the core wire, with tear strings and a manufacturing apparatus that delivers and warps the tension members to facilitate exposure of the core wire.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the sheath and tension member are integrated in a non-slot structure, then the cable diameter and weight are reduced, but the optical fiber core wire is caught in the sheath during dismantling causing increased optical loss

Engineering Contradiction:
Improvecable weightVSAvoidoptical loss
Core Design Contradiction:
Weight of moving objectVSObject-affected harmful factors

Solution Approach 1:

The tension member is divided into multiple segments along its length, with each segment independently capable of warping outward from the cable core axis. This segmentation allows the tension member to maintain integration with the sheath for weight reduction while providing localized warping action to prevent core wire entanglement during dismantling.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The tension member is designed with dynamic warping capability, allowing it to change its position from a fixed integrated state during cable usage to a warped outward state during dismantling. This dynamic behavior enables the tension member to adapt its function based on the operational phase, preventing optical loss while maintaining structural integration.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If the tension member is disposed inside the sheath in a non-slot structure, then the cable structure is simplified, but the risk of optical loss increase during dismantling is heightened

Engineering Contradiction:
Improvecable structureVSAvoidoptical loss risk
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

Different portions of the tension member are designed with different properties: the overall structure maintains integration with the sheath for simplicity, while specific local portions are equipped with warping ability to prevent optical loss. This local differentiation resolves the contradiction between structural simplicity and reliability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The warping portion of the tension member acts as an intermediary mechanism between the integrated sheath-tension member structure and the optical core wire. During dismantling, this intermediary warps outward to create space and prevent the core wire from being caught, thereby maintaining reliability without complicating the overall structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If the sheath is torn during dismantling, then the optical fiber can be accessed, but the optical fiber core wire becomes caught and optical loss increases

Engineering Contradiction:
Improvedismantling processVSAvoidoptical loss
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The tension member is pre-configured with warping ability that activates in anticipation of the sheath tearing process. As the sheath begins to tear, the tension member automatically warps outward to counteract the catching action that would otherwise occur, thereby preventing optical loss before it can happen during the dismantling operation.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The tension member's warping ability, which could be seen as a structural complexity, is converted into a beneficial protective mechanism during dismantling. The warping action that might otherwise be considered an anomaly becomes the key feature that prevents optical loss, transforming a potential harm into a protective benefit.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentEP4350408B1Fiber-optic cable and fiber-optic cable manufacturing device
Publication Date: 2025.12.31 NT T INC
  • EP4350408B1 patent drawingFigure 1-a~1-c
  • EP4350408B1 patent drawingFigure 2-a~2-b
  • EP4350408B1 patent drawingFigure 3

AI summary

An object of the present disclosure is to realize an optical fiber cable which avoids an optical fiber core wire caught in a sheath and prevents an increase in optical loss owing to bending of the optical fiber core wire. In order to achieve the above object, an optical fiber cable according to the present disclosure includes: a cable core having a plurality of optical fiber core wires; a sheath covering the cable core; and at least two or more tension members, having warping ability outward from an axial center of a cable core, disposed inside the sheath along the cable core, and any one of the tension members is disposed at a position laying along a position of another of the tension members with the axial center of the cable core sandwiched between the positions.