Permeable Airbag Inflator Tubes for Quiet Rapid Deployment
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Solution Overview
Problem
Existing personal impact protection systems, such as inflatable airbags for the elderly, produce loud noises during deployment due to rapid gas release, which is detrimental in environments like nursing homes and hospitals, and require noise suppression mechanisms that are compact, lightweight, and conformable to human anatomy.
Innovation Solution
A combination of gas restriction, dissipation, and expansion containment mechanisms, including permeable tubes, baffling, and sacrificial structures, to attenuate noise from inflator discharge in personal protective airbags/cushions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If rapid gas release is used to inflate the airbag quickly, then the response time and protection effectiveness are improved, but the noise level increases to 150 decibels or more
Solution Approach 1:
The gas flow path is divided into multiple segments using a multi-chamber housing structure with internal baffles and flow directors. The single gas source is segmented into multiple discharge paths that release gas sequentially or simultaneously through controlled openings, reducing the peak noise level while maintaining inflation speed.
Solution Approach 2:
An intermediary noise suppression chamber is introduced between the gas source and the external environment. This chamber contains the rapid gas expansion and uses controlled flow paths, baffles, and acoustic absorption materials to attenuate noise before the gas reaches the wearer, while still delivering sufficient gas for airbag inflation.
2Object-generated harmful factors
If noise suppression mechanisms are added to reduce sound levels, then the noise level is reduced, but the device size and weight increase
Solution Approach 1:
The noise suppression housing is constructed from flexible, thin-walled materials that can attenuate noise through their structure and any contained acoustic materials, while minimizing weight. The housing itself acts as part of the noise suppression mechanism rather than requiring heavy rigid enclosures.
Solution Approach 2:
Porous acoustic absorption materials are integrated into the housing structure and flow paths. These materials effectively absorb and attenuate noise across a range of frequencies while having low density and minimal weight impact on the overall device.
3Object-generated harmful factors
If noise suppression mechanisms are added to reduce sound levels, then the noise level is reduced, but the device complexity increases
Solution Approach 1:
The noise suppression functions are merged with the existing airbag inflation system components. The housing serves dual purposes as both structural containment for the gas source and as the noise suppression chamber. Flow directors and baffles are integrated into the existing gas delivery pathways rather than being separate add-on components.
Solution Approach 2:
Existing components are designed to serve multiple functions. The housing provides structural support, contains the gas source, and acts as the noise suppression chamber. Flow directors simultaneously guide gas flow and serve as acoustic baffles. This multi-functionality reduces the number of separate components needed for noise suppression.
4Weight of moving object
If the device is made compact and lightweight for personal wear, then the comfort and wearability are improved, but the noise suppression effectiveness is reduced
Solution Approach 1:
The acoustic properties of the housing and contained materials are optimized to maximize noise attenuation per unit volume and weight. The thickness, density, and configuration of acoustic materials are carefully selected to achieve the required noise reduction in a compact package. The housing geometry is optimized to provide effective noise suppression while minimizing overall device dimensions.
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
Effectively suppresses loud sounds associated with gas discharge while maintaining a lightweight and flexible design suitable for personal use, reducing noise levels without startling individuals or bystanders.
Implementation Method 1
a flexible permeable inner tube...serves to provide a first chamber for inflator discharge gas to exit from housing discharge port and at least partially expand along the length of permeable inner tube
Implementation Method 2
Upon inflator activation...inflator discharge gas to exit from housing discharge port and at least partially expand along the length of permeable inner tube
Implementation Method 3
sound absorption layer...to further dissipate energy produced by inflator discharge gas exiting from permeable inner tube
Data Source
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AI summary
Systems including noise suppression devices for personal impact protection systems are provided. One such system includes an inflator having an inflator discharge port; a flexible permeable inner tube configured to receive gas from the inflator via the inflator discharge port; and a flexible outer tube surrounding the inner tube and configured to receive gas from the inner tube, the outer tube including one or more outer tube discharge ports. Another such system includes an inflator having an inflator discharge port; a flexible non-permeable tube configured to receive gas from the inflator via the inflator discharge port; and a permeable gas diffuser element disposed in or adjacent to the tube, the diffuser element being configured to receive gas from the inflator via the inner tube.