Optical Fiber Cable With Flexible Tubes For High-Density Packing

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Solution Overview

Problem

Existing optical fiber cables face challenges in achieving high-density packing and maintaining operability during intermediate branching, as loose tube types expose fibers when the sheath is torn, while slot-less types scatter fibers without tubes, making it difficult to manage them effectively.

Innovation Solution

An optical fiber cable design featuring intermittent coupling type optical fiber ribbons within flexible tubes made of low-density polyethylene, allowing for high-density packing and easy disassembly by using a cable sheath with a lower Young's modulus and incorporating a tearing cord for controlled exposure of fibers during branching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If hard tubes are used to accommodate optical fiber ribbons, then the tubes maintain structural stability, but the cable cannot achieve high-density packing due to large gaps between rigid tubes

Engineering Contradiction:
Improvestructural stability of tubesVSAvoidpacking density of optical fibers
Core Design Contradiction:
Stability of the object's compositionVSQuantity of substance

Solution Approach 1:

The patent changes the material parameter of the tubes from hard materials (PBT, metal) to flexible materials (low-density polyethylene) with lower Young's modulus. This parameter change allows the tubes to be elastically deformed during cable assembly, enabling high-density packing of optical fiber ribbons while maintaining structural integrity during operation.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If slot-less design is used without tubes, then high-density packing is achieved, but fibers scatter in all directions when the sheath is torn, deteriorating operability

Engineering Contradiction:
Improvepacking density of optical fibersVSAvoidoperability during intermediate branching
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The patent divides the cable structure into segmented tubes, each accommodating specific optical fiber ribbons. When the cable sheath is torn during intermediate branching, only the specific tube containing the desired fibers is exposed and removed, while other tubes remain intact. This segmentation prevents fiber scattering and improves operability during maintenance operations.

Inventive Principle:
Principle #1Segmentation

3Ease of manufacture

If flexible tubes with lower Young's modulus are used, then the tubes can be easily deformed for high-density packing, but the tubes may lack sufficient structural strength

Engineering Contradiction:
Improvedeformability of tubesVSAvoidstructural strength of tubes
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent employs flexible tubes made of low-density polyethylene that can be elastically deformed during the cable assembly process to achieve high-density packing. The flexible material allows the tubes to conform to the cable core shape while maintaining sufficient structural strength to protect optical fibers during operation and intermediate branching operations.

Inventive Principle:
Principle #30Flexible shells and thin films

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The design enables high-density fiber packing and improved operability during intermediate branching by using flexible tubes that can be easily deformed and disassembled, reducing gaps within the sheath and ensuring controlled exposure of fibers for efficient accommodation.

Implementation Method 1

flexible tubes made of low-density polyethylene, allowing for high-density packing and easy disassembly by using a cable sheath with a lower Young's modulus

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3410167B1Optical fiber cable
Publication Date: 2021.07.21 SUMITOMO ELECTRIC INDUSTRIES LTD
  • EP3410167B1 patent drawingFigure 1~2
  • EP3410167B1 patent drawingFigure 3~4

AI summary

An optical fiber cable comprises an optical unit having a plurality of stranded optical fiber ribbons, a tube having the optical unit accommodated therein, and a cable sheath covering an outer side of an assembly including a plurality of the tubes, each optical fiber ribbon is intermittently provided with coupling portions, at which adjacent optical fibers are coupled therebetween, and non-coupling portions, at which adjacent optical fibers are not coupled therebetween, in a longitudinal direction between a part or all of the optical fibers in a state where the optical fibers are arranged in parallel, each tube has a Young's modulus lower than a Young's modulus of the cable sheath, and the assembly is in a state where a part of the tubes is in surface contact with the cable sheath with the tubes being elastically deformed with respect to another tube inside the cable sheath.