Optical Fiber Cable Ripcord Restraint Using Elastic Reinforcing Sheet

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Solution Overview

Problem

The movement of ripcords in the circumferential direction of optical fiber cables is uncontrolled, making the tearing operation difficult due to the space between the cable main body and the reinforcing sheet.

Innovation Solution

The optical fiber cable design includes a protective layer that partially contacts the cable main body, limiting the ripcord movement by elastic deformation, with specific angle and distance constraints, and overlapping directions to enhance workability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a space is formed between the cable main body and the reinforcing sheet to accommodate ripcords, then the ripcords can be disposed in the cable structure, but the ripcords can move in the circumferential direction making the tearing operation difficult

Engineering Contradiction:
Improveease of disposing ripcordsVSAvoidease of tearing operation
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The protective layer is designed as an elastic thin film that can be deformed to compress the cable main body, creating contact pressure that restrains the ripcords in the circumferential direction while still allowing them to be disposed in the space between the cable main body and reinforcing sheet

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the physical state of the protective layer from a rigid structure to an elastic deformable structure, allowing it to dynamically adjust its shape during manufacturing and service to maintain contact with the cable main body and restrain ripcord movement

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the protective layer is made to contact the cable main body to limit ripcord movement, then the workability of tearing operation is improved, but the structural complexity increases

Engineering Contradiction:
Improveworkability of tearing operationVSAvoidstructural complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The protective layer serves multiple functions simultaneously: it protects the cable main body, accommodates the ripcords in the space between the cable main body and reinforcing sheet, and through elastic deformation creates contact pressure to restrain ripcord movement in the circumferential direction

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 limits ripcord movement, improving the workability of the tearing operation and maintaining the cable's structural integrity.

Implementation Method 1

a protective layer that accommodates the cable main body in a state of holding an elastic deformation of the cable main body toward an inside of the cable main body

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4685536A1Optical fiber cable and method for manufacturing optical fiber cable
Publication Date: 2026.01.28 FUJIKURA LTD
  • EP4685536A1 patent drawingFigure 1
  • EP4685536A1 patent drawingFigure 2
  • EP4685536A1 patent drawingFigure 3

AI summary

An optical fiber cable 1 includes a cable main body 10 that includes an optical fiber 21, a reinforcing sheet 60 and an outer sheath 70 that accommodates the cable main body 10, and a ripcord 50A and 50B that is disposed in a space 65 formed between the cable main body 10 and the reinforcing sheet 60. The reinforcing sheet 60 is in partial contact with the cable main body 10 in a state of holding an elastic deformation of the cable main body 10 toward an inside of the cable main body10.