Optical Cable Transitional Area for Thermal Shrinkage Control

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Solution Overview

Problem

Optical cables used for indoor and outdoor applications face issues with shrinkage due to temperature differences, leading to tension loads on optical fibers and potential data transmission disruptions, especially at plug connections, where different materials expand differently, causing attenuation and potential fiber damage.

Innovation Solution

The optical cable design incorporates a tight-buffered optical cable surrounded by a protective sleeve with an intermediate layer containing tension-resistant elements, and a cable sheath with a transitional area where the sheath material is mixed with these elements, ensuring a strong mechanical coupling that minimizes shrinkage and maintains uniform length changes with temperature variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional optical cable structures are used with separate protective sleeves and cable sheaths, then the cable can be manufactured with standard processes, but the different materials expand differently with temperature changes causing shrinkage and tension loads on optical fibers

Engineering Contradiction:
Improvecable performance stabilityVSAvoidcable structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the protective sleeve and cable sheath into a single integrated component made of the same material. This merging eliminates the interface between different materials, preventing differential thermal expansion and the resulting shrinkage that causes fiber tension and signal loss. The integrated structure maintains cable reliability across temperature variations without requiring complex multi-material construction.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of manufacture

If the cable sheath is made from a single material throughout, then manufacturing is simplified, but the cable exhibits greater shrinkage response to temperature changes

Engineering Contradiction:
Improvecable manufacturing simplicityVSAvoidshrinkage resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies local quality by creating a transitional area within the cable sheath where the material composition is modified. This transitional zone has different properties than the main cable sheath body, specifically designed to reduce shrinkage response. The local modification allows the cable to maintain ease of manufacture with a predominantly uniform structure while incorporating a targeted shrinkage-reducing feature at the critical interface region.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If the cable uses multiple separate components (protective sleeve, intermediate layer, cable sheath), then each component can be optimized independently, but the assembly exhibits undesirable shrinkage due to lack of mechanical coupling

Engineering Contradiction:
Improvecomponent optimization flexibilityVSAvoiddimensional stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent merges the protective sleeve and cable sheath into one integrated component, eliminating the intermediate layer and creating inherent mechanical coupling. This unified structure prevents relative movement and shrinkage between components during temperature changes. The integration maintains the ability to optimize the overall cable design while ensuring dimensional stability through the eliminated component interfaces.

Inventive Principle:
Principle #5Merging (Combining)

4Weight of moving object

If the optical cable is designed to be lightweight and compact for easy installation, then handling and processing become easier, but the cable becomes more susceptible to tension loads from thermal expansion differences

Engineering Contradiction:
Improvecable weightVSAvoidfiber tension resistance
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent combines the protective sleeve and cable sheath into a single integrated component, eliminating the interface that causes differential thermal expansion. This merging removes the source of tension loads on the optical fiber while maintaining the cable's lightweight and compact design. The integrated structure allows the cable to remain easy to handle and install without compromising fiber protection against thermal stresses.

Inventive Principle:
Principle #5Merging (Combining)

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

This design significantly reduces shrinkage, ensuring the optical cable maintains consistent length and reduces the risk of fiber damage, allowing for easier installation and reduced attenuation across varying temperatures, making it suitable for diverse applications without the need for additional reinforcement or adapters.

Implementation Method 1

a cable sheath is pressure-extruded around the intermediate layer thus resulting in a transitional area along the inner surface of the cable sheath, in which the material of the cable sheath is mixed with the material of the intermediate layer

Methodology Applied
Scientific EffectPressure extrusion: Extrusion

Implementation Method 2

the resultant temperature differences between a heated building and the outdoor area, which may be considerably cooler, leads to different expansion of the optical cable

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP2105776B1Optical cable and method for producing an optical cable
Publication Date: 2016.10.19 CCS TECHNOLOGY INC
  • EP2105776B1 patent drawingFigure 1~2
  • EP2105776B1 patent drawingFigure 3
  • EP2105776B1 patent drawingFigure 4

AI summary

An optical cable (1) comprises a tight-buffered optical cable (40) and a protective sleeve (20) which surrounds the tight-buffered optical cable (40). An intermediate layer (12) surrounds the protective sleeve (20) and has tension-resistant elements (14). Furthermore, the optical cable contains a cable sheath (10) which surrounds the intermediate layer (12), and a transitional area (15) facing its inner surface. In this transitional area (15), the material of the cable sheath (10) is mixed with the tension-resistant elements (14) of the intermediate layer (12).