Reusable Evacuation Slide Restraint With Torsion Spring Reset
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Solution Overview
Problem
Existing releasable restraints in evacuation assemblies are typically single-use, which limits their effectiveness and increases costs due to the need for multiple deployments during testing and certification.
Innovation Solution
A reusable releasable restraint system comprising a bracket, pins, a puller, and torsion springs that allow the restraint to separate and reattach, enabling multiple uses by controlling the deployment of evacuation slides through internal pressure thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shear pin is used as a releasable restraint, then the restraint can release in response to internal slide pressure, but the restraint becomes single-use and cannot be reused
Solution Approach 1:
The restraint system is divided into separable components: a bracket assembly and a puller assembly that can be independently separated and reattached. The shear pin only releases the puller from the bracket, not the entire restraint system, enabling the bracket to be reused while the puller can be replaced if needed.
Solution Approach 2:
The design allows selective discarding of only the consumable shear pin component while recovering and reusing the more valuable bracket and tube portions. The bracket assembly remains intact and can be reattached to the puller assembly for subsequent deployment cycles.
2Device complexity
If a single-use restraint is used, then the restraint can be simple in design, but multiple restraints are needed for testing and certification increasing costs
Solution Approach 1:
The restraint is segmented into reusable bracket/tube portions and a disposable shear pin portion. This segmentation allows the complex, expensive bracket assembly to be reused multiple times during testing and certification, while only the simple, inexpensive shear pin needs replacement.
Solution Approach 2:
The bracket assembly serves multiple functions: it provides the structural mounting point, houses the torsion spring mechanism, and can be repeatedly attached to different puller assemblies. This multi-functionality allows a single bracket to support multiple deployment cycles and testing iterations.
3Adaptability or versatility
If a reusable restraint with torsion spring is used, then the restraint can be reset and reused, but the device complexity increases
Solution Approach 1:
The torsion spring mechanism is segmented into the bracket portion (housing and spring) and the puller portion (tubes and pins). This segmentation contains the complexity within the reusable bracket while keeping the replaceable puller relatively simple, making the overall system more manageable.
Solution Approach 2:
The torsion spring provides self-service by automatically resetting the puller tubes to their initial position after deployment. When the shear pin releases, the torsion spring's stored energy automatically returns the tubes to their starting position, eliminating the need for manual resetting operations.
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 system allows for consistent and controlled deployment of evacuation slides, reducing costs by enabling multiple uses of the restraints, particularly in slide testing and certification processes.
Implementation Method 1
A torsion spring may be configured to bias the first tube portion toward the first pin and to bias the second tube portion toward the second pin
Data Source
AI summary
A releasable restraint may comprise a bracket and a puller removably coupled to the bracket. A first tube portion and a second tube portion may be rotatably coupled to the puller. A torsion spring may be configured to bias the first tube portion in a first circumferential direction and the second tube portion in a second, opposite circumferential direction.