Aircraft Crew Egress Hatch Support Strap Folding Mechanism
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Solution Overview
Problem
Existing aircraft designs lack efficient and safe crew egress pathways that allow crew members to exit the aircraft quickly and safely, particularly in emergency situations.
Innovation Solution
The implementation of a crew egress pathway exit assembly that includes a movable exit hatch supported by an exit hatch support structure and at least one support strap. The support strap is designed to fold and unfold seamlessly, allowing the exit hatch to move from a stowed to a deployed position and vice versa, while ensuring the crew member's safe exit into the passenger cabin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a movable exit hatch is implemented for crew egress, then crew safety and egress efficiency are improved, but device complexity increases due to the need for support straps and folding mechanisms
Solution Approach 1:
The support strap is divided into multiple sections (first section, second section, third section) with different bending stiffness characteristics. This segmentation allows each section to perform specific functions: the first section provides structural support, the second section enables folding at predetermined positions, and the third section connects to the hatch. This resolves the contradiction by making the complex mechanism more manageable and reliable through functional segmentation.
Solution Approach 2:
The support strap is designed with varying bending stiffness along its length, allowing it to be rigid in some sections and flexible in others. This dynamic property enables the strap to maintain structural integrity when supporting the hatch while simultaneously allowing it to fold neatly into a compact footprint during retraction. This resolves the contradiction between reliability (needing rigidity) and device complexity (needing flexibility for storage).
2Volume of moving object
If the support strap is designed to fold at predetermined positions, then the folded footprint is minimized for compact storage, but manufacturing precision requirements increase
Solution Approach 1:
The support strap is designed with non-uniform local properties: different sections have different bending stiffness characteristics. The first section has higher bending stiffness for structural support, while the second section has lower bending stiffness to facilitate folding. This local quality differentiation allows the strap to achieve compact folded dimensions without requiring extremely high manufacturing precision across the entire component, as each section is optimized for its specific function.
3Ease of operation
If the exit hatch is designed to open into the passenger cabin, then ease of operation is improved for crew egress, but harmful factors increase due to potential disruption to passenger seating
Solution Approach 1:
The support strap is pre-configured with predetermined folding positions and bending stiffness characteristics that guide it to fold into a specific compact footprint. This preliminary design ensures that when the hatch is opened for crew egress, the strap automatically retracts to a predetermined position that minimizes disruption to passenger seating. This resolves the contradiction by having the system prepare the optimal configuration in advance rather than requiring manual adjustment during emergency egress.
Data Source
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AI summary
Crew egress pathways and crew egress pathway exits in aircraft, with the crew egress pathway exits comprising apparatuses, systems, and methods for reliable deployment and stowage of crew egress pathway exit hatch (29) support straps (40), with the crew egress pathway exit hatches (29) configured to deploy within aircraft passenger compartments in aircraft, and wherein the support straps (40) are configured to fold within a predetermined folded strap support footprint when moving a crew egress pathway exit hatch (29) from a deployed position to a stowed state.