Tray Table Arm Assembly with Crash-Triggered Constraint Release
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Solution Overview
Problem
Centrally placed latch or slider in tray table assemblies can pose a hazard during crashes, as it may cause the seat back to twist, leading to separation of the tray table from the seat back, potentially exposing passengers to injury.
Innovation Solution
Incorporating arms with constraint release features that override normal motion limits during high-force scenarios, such as a deformable stopper or spring, allowing the tray table to move with the seat back and reducing the risk of separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a latch or slider is centrally placed to retain the tray table assembly in a stowed position, then the number of components is reduced and complexity is minimized, but during a crash scenario the seat back may twist causing separation of the tray table from the seat back, exposing projecting features that pose an increased risk of injury to passengers
Solution Approach 1:
The stopper is designed to dynamically change its state from a rigid constraint to a deformable element under high-force conditions. During normal operation, the stopper maintains its rigid structure to prevent rotation beyond the stowed position. During a crash scenario, the stopper deforms to allow continued rotation, enabling the tray table to follow the seat back's twisting motion and avoid separation and injury risk.
Solution Approach 2:
The stopper's mechanical properties are designed to change under different force conditions. The stopper has a yield strength that allows it to maintain rigidity under normal operating forces (keeping the tray table securely stowed) but deform when subjected to high-force crash scenarios (allowing the tray table to move with the seat back). This parameter change resolves the contradiction between maintaining structural integrity and allowing safe motion during crashes.
2Reliability
If a stopper is used to prevent rotation of the tray table assembly beyond the stowed position, then the tray table is securely retained, but during a crash the stopper may prevent the tray table from moving with the seat back, causing separation and injury hazard
Solution Approach 1:
The stopper transitions from a static constraint to a dynamic element that adapts to loading conditions. Under normal conditions, it provides reliable retention by preventing rotation. Under crash conditions, it becomes dynamic by deforming to allow motion, thus resolving the contradiction between reliable retention and injury prevention.
Solution Approach 2:
The stopper's potential harm (preventing motion during crash) is converted into a benefit through controlled deformation. The deformation, which might be seen as a failure of the retention mechanism, actually becomes the safety feature that allows the tray table to move with the seat back, converting the harmful rigid constraint into a beneficial compliant element during crash scenarios.
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
Enhances passenger safety by allowing the tray table to pivot freely with the seat back during crashes, reducing the risk of injury from protruding features.
Implementation Method 1
Incorporating arms with constraint release features that override normal motion limits during high-force scenarios, such as a deformable stopper or spring
Data Source
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AI summary
Described are assemblies that include elements of a tray table, such as for an aircraft or other passenger craft. A tray table body can be movable between a stowed configuration and a deployed configuration. A set of arms may support the table body relative to a seat back in the stowed configuration and in the deployed configuration. In response to movement of the seat back (such as in a crash scenario), the arms may permit release of a constraint of the tray table body that would otherwise inhibit the tray table body from moving with the seat back.