Optical Fiber Junction Box Sealing Member Design

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Solution Overview

Problem

The existing connection methods for optical fibers in buildings often result in imperfect seals due to diameter mismatches between the cables and sealing members, leading to either inadequate sealing or excessive tightening, and require multiple sealing member models for different cable diameters, complicating stock management and installation.

Innovation Solution

A connection box with a sealing member made of elastic thermoplastic material, featuring a sealing film that extends non-parallel to the orifice axis, allowing for adaptable clamping and improved tightness across varying cable diameters, and facilitating easy cable passage through pre-cut or perforated designs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single sealing member model is used for all cable diameters, then device complexity and stock management are simplified, but sealing performance deteriorates due to diameter mismatch

Engineering Contradiction:
Improvesealing member model varietyVSAvoidsealing performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The sealing member is designed with a conical internal surface that can adapt to cables of different diameters, allowing a single universal model to replace multiple diameter-specific models. The cone geometry enables the sealing surface to conform to various cable sizes while maintaining effective sealing contact.

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

Solution Approach 2:

The sealing member incorporates a conical surface with a specific angle range (30-60 degrees) that allows the sealing geometry to change parameters according to the cable diameter. This parameter adaptation enables the same sealing member to effectively seal different cable sizes without requiring multiple models.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the sealing member is tightly clamped to ensure seal, then sealing performance improves, but cable damage risk increases due to excessive tightening

Engineering Contradiction:
Improvesealing performanceVSAvoidcable integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The sealing member applies clamping force locally at the conical sealing surface rather than uniformly along the entire cable length. This localized quality approach concentrates the sealing action at the interface between the cone and cable, reducing the overall clamping force required and minimizing stress on the cable.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The conical sealing surface creates a dynamic sealing mechanism where the contact pressure is distributed along the inclined surface. This dynamic geometry allows the sealing force to be applied progressively along the cone angle, preventing excessive localized stress that could damage the cable while maintaining effective sealing.

Inventive Principle:
Principle #15Dynamics

3Strength

If the sealing member is loosely clamped to protect cable, then cable integrity is maintained, but sealing performance deteriorates due to insufficient contact

Engineering Contradiction:
Improvecable integrityVSAvoidsealing performance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The conical surface geometry changes the relationship between clamping force and sealing contact pressure. The cone angle transforms a relatively low clamping force into an effective sealing pressure at the contact interface, allowing adequate sealing with reduced overall clamping force that protects the cable.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The conical surface introduces a curved geometry that increases the contact area between the sealing member and cable compared to a flat surface. This curvature distributes the sealing force over a larger area, improving sealing effectiveness while reducing the peak stress on the cable.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 solution ensures a reliable and adaptable seal for optical fibers with different diameters, simplifying installation by using a single sealing member type and enhancing the connection box's sealing performance and ease of use.

Implementation Method 1

The member is made of elastic material, preferably a thermoplastic material... Such a material may have, in addition to a domain of elastic deformation, a domain of plastic deformation. The member is thus able to make contacts having a very good seal respectively with the wall and the cable.

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

Such a material may have, in addition to a domain of elastic deformation, a domain of plastic deformation.

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP2156229B1Junction box for optical fibres, including sealing means
Publication Date: 2011.10.12 FREE
  • EP2156229B1 patent drawingFigure 1
  • EP2156229B1 patent drawingFigure 2~3
  • EP2156229B1 patent drawingFigure 4~5

AI summary

The invention relates to a junction box (16, 18; 20a-d) for optical fibres, including a wall (28a) having at least one opening (46a). The box includes a member (48a) which is provided with an opening (208) for the passage of an optical fibre cable (13, 15) and which can be received in the above-mentioned opening (46a), forming a contact with the wall (28a). The box also includes means (217) for clamping said member (48a) at a distance from the opening in order to form a contact with the cable (13, 15).