Inflatable Harness Fabric Tubes for Aircraft Oxygen Masks
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Solution Overview
Problem
Conventional inflatable crew masks with silicone inner tubes are prone to puncture and abrasion, leading to leakage and failure due to stress and fatigue from repeated inflation cycles, resulting in a limited lifespan of approximately 1,000 inflations.
Innovation Solution
The inflatable harness assembly features outer layers of fabric material with an airtight coating and an inner core of resilient, elastic material, allowing for robust inflation and deflation without plastic deformation, utilizing pleated fabric tubes that expand radially and axially to secure the mask over the user's head, with elastic bands providing elasticity and maintaining tension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicone inner tubes are used for inflatable harness, then inflation and deflation can be achieved, but the tubes are prone to puncture and abrasion leading to leakage and failure
Solution Approach 1:
The patent applies composite materials by combining fabric material with elastomeric material to create the inflatable tube structure. The fabric material provides puncture and abrasion resistance, while the elastomeric material provides elasticity and airtightness. This composite construction resolves the contradiction by eliminating the silicone inner tube's susceptibility to puncture and abrasion while maintaining the necessary inflation and deflation functionality.
Solution Approach 2:
The patent changes the material parameters from silicone to a combination of fabric and elastomeric materials. This parameter change transforms the structural properties of the inflatable tube, providing both the durability needed to resist puncture and abrasion and the elasticity required for repeated inflation cycles without failure.
2Stability of the object's composition
If silicone inner tubes with Nomex braided material are used, then radial expansion can be controlled, but the tubing deforms under repeated inflation cycles causing hole formation and leakage
Solution Approach 1:
The patent uses composite materials consisting of fabric material with elastomeric coating or laminate to replace the silicone inner tube combined with Nomex braid. This composite structure provides both radial expansion control and resistance to deformation under repeated cycling, extending the service life from approximately 1,000 cycles to at least 25,000 cycles without failure.
Solution Approach 2:
The patent employs flexible fabric material with elastomeric coating or laminate to create the inflatable tube structure. This flexible shell construction maintains radial expansion control while being resistant to the deformation and hole formation that occurs with repeated inflation cycles in traditional silicone tubes.
3Ease of operation
If elastic material is added to provide harness contraction after deflation, then secure fit is achieved, but the complexity of the tube structure increases
Solution Approach 1:
The patent merges the functions of the inflatable tube structure and the elastic contracting element into a single integrated component. The fabric-elastomeric composite tube itself provides both the inflatable structure and the elastic contracting force when deflated, eliminating the need for separate elastic bands or components and reducing overall structural complexity.
Solution Approach 2:
The inflatable tube in the patent serves multiple functions: it provides the inflatable structure for head coverage, maintains radial expansion control, and provides elastic contracting force when deflated. This multi-functionality eliminates the need for separate components and simplifies the overall harness structure while maintaining secure fit capability.
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 enables the inflatable harness to withstand at least 25,000 inflations without failure, ensuring reliable oxygen supply and secure fit, addressing the limitations of conventional silicone tube-based systems by providing a more robust and durable design.
Implementation Method 1
an inner airtight coating to allow the one or more inflatable tubes to be inflated
Implementation Method 2
The inner core of resilient, elastic material is configured to bias the one or more inflatable tubes to a first length when the one or more inflatable tubes are in the normally deflated configuration
Data Source
AI summary
The inflatable harness assembly for an aircraft oxygen crew mask includes one or more inflatable tubes having an outer layer of fabric material with an airtight coating for inflating the inflatable harness assembly. The inflatable tubes include an inner core of resilient, elastic material fixedly connected between first and second ends of the inflatable tubes that biases the inflatable tubes to shorten when the tubes are deflated. Inflation of the tubes them to expand the outer layer of material radially outwardly and lengthen axially, to allow the harness assembly to be placed over the user's head. Deflation of the tubes causes the aircraft inflatable harness assembly to grip the user's head with a desired head tension.