Optical Cable Arcuate Reinforcement for Compact Unwinding

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Solution Overview

Problem

Existing optical telecommunication cables are bulky and have a preferential direction of curvature due to rigid and flexible reinforcements, making them difficult to unwind without twisting and resulting in a large final cable diameter.

Innovation Solution

An optical cable design featuring a mechanical reinforcement element with an angular extent of less than 360°, arranged in an arcuate configuration with its concavity towards the optical core, which is integral with the surrounding medium but only in contact with the optical core when necessary, and composed of natural or synthetic fibers or thermoplastic/thermosetting polymers, allowing for a compact structure with reduced preferential radius of curvature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If rigid and flexible reinforcements are used in optical cables, then mechanical strength and resistance to traction and compression are improved, but the cable becomes bulky and develops a preferential direction of curvature

Engineering Contradiction:
Improveresistance to traction and compressionVSAvoidcable diameter
Core Design Contradiction:
StrengthVSVolume of moving object

Solution Approach 1:

The reinforcement structure is segmented from a traditional 360° circular arrangement into discrete arcuate elements with angular extent less than 360°. This segmentation allows the cable to maintain mechanical strength while reducing overall volume and eliminating the preferential curvature direction imposed by complete circular reinforcements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The reinforcement elements are designed with asymmetric arcuate geometry where the concavity faces the optical core. This asymmetric configuration provides mechanical support while allowing the cable to bend more freely in multiple directions, eliminating the preferential curvature direction that would result from symmetric circular reinforcements.

Inventive Principle:
Principle #4Asymmetry

2Strength

If rigid reinforcements are embedded in the sheath, then mechanical reinforcement is improved, but the radial thickness of the sheath increases causing a large final cable diameter

Engineering Contradiction:
Improvemechanical reinforcementVSAvoidradial thickness of sheath
Core Design Contradiction:
StrengthVSLength of stationary object

Solution Approach 1:

Instead of applying reinforcement through complete circular rigid elements, the invention uses partial arcuate reinforcements covering less than 360° of the circumference. This partial action provides sufficient mechanical reinforcement while significantly reducing the radial thickness required in the sheath, thereby decreasing the final cable diameter.

Inventive Principle:
Principle #16Partial or excessive action

3Stability of the object's composition

If complete circular reinforcements are used, then structural stability is improved, but the cable cannot be unwound smoothly without twisting

Engineering Contradiction:
Improvestructural stabilityVSAvoidunwinding capability
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The continuous circular reinforcement is segmented into arcuate elements with gaps between them. This segmentation disrupts the continuous structural constraint that causes twisting during unwinding, while each individual arcuate element maintains local structural stability. The result is a cable that can be unwound smoothly without twisting.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3387474B1Optical cable comprising a mechanical reinforcing element
Publication Date: 2020.03.18 ACOME SA
  • EP3387474B1 patent drawingFigure 1~2
  • EP3387474B1 patent drawingFigure 3~4
  • EP3387474B1 patent drawingFigure 5~6

AI summary

The present invention in particular relates to an optical cable that comprises: an optical core (2) consisting of at least one optical fibre (20) that it is optionally protected by a protective cladding (21); around this optical core (2), a cladding called the "exterior cladding" (3); at least one mechanical reinforcing element (4) that has a thickness smaller than its width and that is placed between the optical core (2) and the exterior cladding (3); characterised in that: said at least one mechanical reinforcing element (4) has an angular extent smaller than 360° and preferably smaller than 180°; said at least one mechanical reinforcing element (4) is placed in a circular arcuate configuration, the concavity of the arc being directed towards said optical core. Said at least one mechanical reinforcing element (4) is securely fastened to the surrounding medium, but simply makes contact with said optical core (2) when it touches the latter.