Evacuation Slide Restraint with Variable Breaking Load
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Solution Overview
Problem
Conventional evacuation slides in aircraft are susceptible to uncontrolled or unsafe deployment due to improper restraint mechanisms, leading to sagging sections getting caught on the aircraft, 'kiting' in high winds, and blocking the emergency exit, which compromises safety and efficiency during evacuations.
Innovation Solution
A restraint system with a longitudinal body and engagement features, featuring a pawl that forms a closed loop with adjustable tensile strength by varying dimensions along its length, allowing controlled deployment of evacuation slides by breaking at a predetermined tensile force, thus preventing retraction and ensuring safe extension from the aircraft to the ground.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional restraint mechanism is used, then the evacuation slide can be deployed, but the deployment becomes uncontrolled or unsafe due to improper restraint
Solution Approach 1:
The restraint mechanism is segmented into multiple discrete engagement features distributed along the longitudinal body, with a pawl that can engage with individual features. This segmentation allows controlled deployment through sequential engagement while maintaining reliability through distributed restraint points.
Solution Approach 2:
The restraint mechanism incorporates dynamic elements including a movable pawl that can traverse engagement features in response to insertion force, and variable dimensional features that allow the restraint to adapt during deployment. The mechanism transitions from a restrained state to a deployed state through controlled mechanical motion.
2Strength
If the restraint forms a closed loop with high tensile strength, then the slide is securely restrained, but the restraint cannot break at predetermined force to allow deployment
Solution Approach 1:
The restraint mechanism features local variations in dimensional properties along its length, with engagement features and longitudinal body sections having different dimensions. This creates localized weak points with predetermined breaking loads while maintaining overall structural integrity, allowing the restraint to break at specific locations under controlled conditions.
Solution Approach 2:
The mechanism utilizes changes in dimensional parameters along the longitudinal body and engagement features to create varying tensile strengths at different locations. By varying cross-sectional dimensions, material distribution, or geometric properties, the restraint achieves different breaking loads at different points, enabling controlled failure at predetermined forces.
3Ease of manufacture
If the dimension of the restraint is uniform along its length, then manufacturing is simplified, but the tensile strength cannot be adjusted to control deployment dynamics
Solution Approach 1:
Rather than uniform dimensions, the restraint mechanism employs local variations in dimensional properties at specific locations along the longitudinal body and engagement features. These localized dimensional differences create predetermined breaking points and controlled strength distribution while maintaining manufacturability through focused geometric variations rather than complex overall structures.
Data Source
AI summary
A restraint may include a longitudinal body having a first end and a second end. The restraint may also include a plurality of engagement features distributed between the first end and the second end. A dimension of at least one of the longitudinal body and the plurality of engagement features may vary along at least a portion of a length of the longitudinal body. The restraint may further include a head disposed at the first end of the longitudinal body. The head may define an aperture and may include a pawl that configured to individually engage the plurality of engagement features. The dimension may vary incrementally or continuously along at least the portion of the length of the longitudinal body from the first end to the second end.