Geometric Restraint for Inflatable Evacuation Slide Deployment
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Solution Overview
Problem
Existing restraint systems for inflatable evacuation slides face challenges in deployment control, particularly in preventing wind deflection and ensuring proper inflation, as they often rely on frangible links or spooled webbing that release based on breaking strength or slide length, which can be inadequate in certain conditions.
Innovation Solution
The use of a frangible link connecting the proximal and middle sections of the slide, combined with a strap and moveable pin assembly, where the pin is retained by a lanyard until the frangible link breaks, allowing the distal section to unfold based on the geometric shape of the slide, providing controlled release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frangible links are used to restrain the slide during inflation, then deployment control is provided, but the slide may be vulnerable to wind deflection and premature release
Solution Approach 1:
The restraint system is divided into multiple independent components: a frangible link for initial containment and a separate geometric restraint mechanism with a moveable pin and strap. This segmentation allows each component to perform its specific function - the frangible link provides initial restraint while the geometric restraint engages only when the slide reaches the proper inflation angle, preventing wind deflection without premature release.
Solution Approach 2:
The geometric restraint mechanism is pre-positioned to engage automatically when the slide reaches a specific geometric configuration (inflation angle). The moveable pin and strap are arranged so that they naturally engage with the slide structure at the correct moment during inflation, providing wind deflection protection only when the slide is properly inflated and ready for deployment.
2Speed
If the slide is extended fully while slightly inflated, then deployment is rapid, but the distal end may be repositioned by wind making the slide unsuitable for transit
Solution Approach 1:
The geometric restraint mechanism applies a counteracting force to prevent wind deflection before it can cause harmful repositioning. The moveable pin and strap create a physical barrier that opposes wind forces during the critical inflation phase, maintaining slide stability until the slide is fully inflated and ready for rapid deployment.
3Reliability
If controls prevent adequate inflation of the slide, then deployment is controlled, but the slide cannot function correctly in emergency situations
Solution Approach 1:
The restraint system transitions from a pressure-based release mechanism (frangible link) to a geometry-based release mechanism (moveable pin and strap). This parameter change ensures that release is controlled by the slide reaching a specific geometric configuration (proper inflation angle) rather than by inflation pressure alone, guaranteeing adequate inflation while maintaining deployment control.
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 solution ensures controlled deployment and unfolding of the slide by releasing the distal section only when the slide reaches a specific angle, preventing premature release and ensuring stability during inflation, thus addressing the limitations of previous systems.
Implementation Method 1
Eventually, inflation pressure causes breakage of the frangible link, permitting further separation of the proximal and middle sections.
Implementation Method 2
Retraction of the pin may occur via tension placed on a lanyard (or other cord or connector) connecting the pin to the proximal section of the slide.
Data Source
AI summary
Detailed are restraints intended principally (but not necessarily exclusively) for inflatable evacuation slides or rafts. At least one such restraint may be designed to release based on geometric shape of an object (such as a slide) rather than merely as a function of its inflation pressure or length. One version of this type of restraint includes a connector pin attached to a cord, with tensioning of the cord eventually retracting the pin to effect release of the restraint.