Shock Absorber Seal Bridging Tool for Early Leakage Detection

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Solution Overview

Problem

Hydraulic fluid leakage in piston and cylinder devices, such as shock absorbers, often goes undetected until the assembly is fitted to a larger system like an aircraft, leading to costly and time-consuming interventions due to the inability of seals to withstand internal pressure.

Innovation Solution

A seal bridging tool with bridging channels and a thick body portion is introduced to divert leaked fluid past the outer seal, allowing for early detection of seal failure, reducing the likelihood of damaged seals being fitted to assemblies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If seals are used to confine hydraulic fluid in the device, then fluid containment is improved, but detection of seal failure is delayed until after assembly fitting

Engineering Contradiction:
Improvefluid containmentVSAvoiddetection delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The bridging tool is installed during assembly before the hydraulic device is fitted to the aircraft, creating a preliminary detection pathway. The bridging channels are formed in advance to provide a direct route for leaked fluid to reach the exterior, enabling early detection of seal failures before the device enters service.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The bridging tool acts as an intermediary device between the sealed intermediate portion and the exterior environment. It provides a controlled pathway through the first seal without compromising the second seal's fluid-tight containment, allowing leaked fluid to be detected externally while maintaining proper seal function.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of substance

If the first seal is made fluid-tight to prevent leakage, then fluid loss is reduced, but damaged seals cannot be detected early

Engineering Contradiction:
Improvehydraulic fluid lossVSAvoidseal failure detection
Core Design Contradiction:
Loss of substanceVSDifficulty of detecting and measuring

Solution Approach 1:

The sealing system is segmented into two distinct seals with different functions: the second seal maintains fluid containment within the hydraulic device, while the first seal is bridged by the tool to allow detection of leaks. This segmentation enables both fluid loss prevention and early failure detection to coexist.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sealing qualities are applied at different locations: the second seal is made substantially fluid-tight for containment, while the first seal location is modified by the bridging tool to have localized channels that permit leak detection without compromising overall fluid containment.

Inventive Principle:
Principle #3Local quality

3Difficulty of detecting and measuring

If a bridging tool is inserted to enable leak detection, then detection capability is improved, but device complexity increases

Engineering Contradiction:
Improveleakage detection capabilityVSAvoidassembly complexity
Core Design Contradiction:
Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The bridging tool is designed as a temporary, non-operational component that is removed before the aircraft enters service. It serves its detection purpose during assembly and testing, then is discarded, avoiding the complexity of permanent detection systems while maintaining detection capability during critical phases.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The bridging tool is extracted from the final operational assembly. It is installed temporarily during assembly to perform its detection function, then removed before service entry. This extraction approach adds minimal permanent complexity to the hydraulic device while achieving the detection objective during critical pre-service phases.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3147209B1Assembly, bridging tool for an assembly and method of forming an assembly
Publication Date: 2019.10.30 MESSIER DOWTY
  • EP3147209B1 patent drawingFigure 1
  • EP3147209B1 patent drawingFigure 2~3
  • EP3147209B1 patent drawingFigure 4~5

AI summary

A tool (40) for bridging an outer dynamic seal (34) in a shock absorber to enable fluid leakage to be more readily determined.