Optical Fiber Cable SZ Twist Untwisting Suppression

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Solution Overview

Problem

Optical fiber cables with twisted SZ shapes experience insufficient suppression of untwisting, leading to movement and potential damage during installation and use.

Innovation Solution

An optical fiber cable design featuring a plurality of optical fiber units twisted in an SZ shape, wrapped with a tube containing fillings that generate frictional forces between the units and the wrapping tube, with a sheath covering the tube to enhance stability and prevent untwisting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If optical fiber units are twisted in an SZ shape, then the cable flexibility and installation workability are improved, but untwisting occurs causing the optical fiber units to move and potentially damage

Engineering Contradiction:
Improveinstallation workabilityVSAvoiduntwisting suppression
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

Fillings are introduced as intermediary elements disposed between adjacent optical fiber units within the wrapping tube. These fillings generate frictional forces that act as a mediating mechanism to suppress untwisting motion while preserving the SZ twist configuration for flexibility and installation workability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The fillings are pre-positioned between the optical fiber units before the cable is put into service. This beforehand cushioning creates a friction-based restraint system that prevents untwisting movement from occurring, cushioning against the destabilizing effect of the SZ twist.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Shape

If fillings are disposed around the optical fiber unit, then the circular cross-section shape is achieved, but untwisting suppression is insufficient

Engineering Contradiction:
Improvecircular cross-sectionVSAvoiduntwisting suppression
Core Design Contradiction:
ShapeVSStability of the object's composition

Solution Approach 1:

Fillings are positioned as intermediary elements specifically between adjacent optical fiber units rather than merely surrounding the entire unit. This intermediary placement creates direct frictional contact that generates restraining forces against untwisting motion, enhancing stability while maintaining the circular cross-section shape.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If fillings are disposed between optical fiber units, then movement is suppressed, but the frictional force generation is insufficient without proper contact arrangement

Engineering Contradiction:
Improvemovement suppressionVSAvoidfrictional force
Core Design Contradiction:
Stability of the object's compositionVSForce

Solution Approach 1:

The fillings are strategically positioned at specific locations between adjacent optical fiber units within the wrapping tube, creating localized zones of high frictional force generation. This local quality approach ensures that frictional forces are generated precisely where needed to suppress untwisting motion effectively.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The filling arrangement extends the frictional force generation into the radial dimension by positioning fillings between units at different angular positions around the cable axis. This multi-dimensional arrangement of fillings creates comprehensive frictional restraint that effectively suppresses untwisting motion from multiple directions.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 effectively suppresses untwisting by generating significant frictional forces, ensuring the optical fiber units remain stable and securely in place, improving installation workability and reducing strain on the cable.

Implementation Method 1

it is possible to generate a frictional force between the outer unit and the fillings and between the fillings and the wrapping tube

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4184229A1Optical fiber cable
Publication Date: 2023.05.24 FUJIKURA LTD
  • EP4184229A1 patent drawingFigure 1
  • EP4184229A1 patent drawingFigure 2
  • EP4184229A1 patent drawingFigure 3

AI summary

An optical fiber cable (100C, 100D) comprises a plurality of optical fiber units (10) each having a plurality of optical fibers (1), and being twisted together in an SZ shape; a wrapping tube (54) that wraps around the plurality of optical fiber units (10); fillings (3a, 3b, 3c, 3d, 13a, 13b, 13c, 13d; 23a, 23b, 23c) disposed inside the wrapping tube (54), wherein the fillings (3a, 3b, 3c, 3d, 13a, 13b, 13c, 13d; 23a, 23b, 23c) include at least one first filing (23a) and at least one second filling (23b) that are located between the adjacent two optical fiber units (10); and a sheath (55) that covers the wrapping tube (54), wherein the first filling (23a) is in contact with the wrapping tube (54), and the second filling (23b) is located more radially inward than the first filling (23a).