Optical Fiber Unit Axial Shrinkage Prevention

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Solution Overview

Problem

When a stretchable tube housing optical fibers is bent, it deforms, causing the inner diameter to shrink and the optical fibers to protrude from the ends, leading to increased exposure and repair difficulties.

Innovation Solution

An optical fiber unit is designed with a tube that has stretchability in the axial direction and a linear body with lower stretchability, where both ends of the linear body are fixed to the tube, preventing further shrinkage during bending and reducing fiber protrusion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a stretchable tube is used to house optical fibers, then the tube can be bent and has stretchability, but the tube deforms when bent causing the inner diameter to shrink and optical fibers to protrude from the ends

Engineering Contradiction:

Improvebendability and stretchability of tubeVSAvoidprotrusion of optical fiber from tube

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The optical fiber is fixed to the inner circumferential surface of the tube at positions corresponding to both end portions of the tube in advance, before bending occurs. This preliminary fixation prevents the fiber from protruding when the tube is subsequently bent, while still allowing the tube to maintain its stretchability and bendability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The tube is divided into multiple sections along its length, with the optical fiber being fixed at specific segments (both end portions) rather than continuously along the entire length. This segmented approach allows the tube to bend and stretch while preventing fiber protrusion at critical locations.

Inventive Principle:

Principle #1Segmentation

2Reliability

If the optical fiber is fixed to prevent protrusion, then fiber protection is improved, but the ability to freely move the fiber within the tube is reduced

Engineering Contradiction:

Improveprevention of fiber protrusionVSAvoidfree movement of fiber within tube

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The optical fiber is fixed only at specific segments (both end portions of the tube) rather than along the entire length. This segmented fixation approach prevents protrusion at critical locations while leaving the intermediate sections free for movement, thus maintaining ease of operation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the optical fiber have different degrees of freedom: the end portions are fixed to prevent protrusion, while the intermediate portions remain free to move. This local differentiation of constraints optimizes both reliability and ease of operation.

Inventive Principle:

Principle #3Local quality

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 configuration effectively prevents or reduces optical fiber protrusion during bending, allowing for easier maintenance and repair by maintaining the fiber within the tube, while maintaining the ability to freely move the fiber within the tube.

Implementation Method 1

a tube (2) having stretchability in the axial direction... Both ends of a linear body (3) are fixed to both end portions of the tube (2) in a state where the tube has been previously shrunk in the axial direction

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS9020314B2Optical fiber unit

Publication Date: 2015.04.28 DMG MORI CO LTD

AI summary

An optical fiber unit (1) includes a tube (2) having stretchability in the axial direction, an optical fiber (4) movably housed in the tube (2), and a linear body (3) formed of a material having less stretchability than the tube (2). Both ends of the linear body (3) are fixed to both end portions of the tube (2) in a state where the tube (2) has been previously shrunk in the axial direction.