Aircraft Tray Table Locking System Impact Safety
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Solution Overview
Problem
Current aircraft seat designs fail to prevent chin entrapment during impacts, as the head deformation causes the chin to catch the upper edge of the shelf, leading to potential severe injuries due to the untimely opening of the tablet during crashes.
Innovation Solution
A locking system comprising a latch, a movement transmission device with a pendulum, and lateral locking elements is integrated into the seat, which prevents the tablet from opening during deformation by engaging a hook to maintain the shelf in the stowed position, thus avoiding chin entrapment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the tray table is made movable between extended and stowed positions for passenger comfort and accessibility, then ease of operation is improved, but the risk of chin entrapment during impact increases due to unintended opening
Solution Approach 1:
The locking system applies preliminary anti-action by automatically engaging the locking element in anticipation of impact forces. The system detects seat deformation through the motion transmission device and preemptively secures the tray table in the stowed position, counteracting the harmful chin entrapment effect before it can occur during the impact event.
Solution Approach 2:
The locking element acts as an intermediary between the tray table and the seat structure. During normal operation, it remains disengaged to allow free movement. During impact, it mediates the connection by engaging with the seat frame through the motion transmission device, preventing the tray table from becoming a hazard while maintaining its structural integrity.
2Reliability
If a locking system is added to prevent tray table movement during impact, then safety against chin entrapment is improved, but device complexity increases
Solution Approach 1:
The locking system employs dynamic characteristics by utilizing the natural motion and deformation of the seat structure during impact. The motion transmission device converts seat deformation into locking element activation, allowing the system to adapt automatically to impact conditions without requiring complex sensors or control systems. The locking element rotates about a pivot joint in response to dynamic forces, providing intelligent locking behavior.
Solution Approach 2:
The locking system performs self-service by automatically detecting and responding to impact conditions through the motion transmission device. The seat deformation itself serves as the triggering mechanism, eliminating the need for external sensors, power sources, or complex control logic. The system uses the impact energy and structural deformation to activate the locking mechanism autonomously.
3Reliability
If the locking element is positioned close to the hook for effective locking, then reliability of tray table retention is improved, but the risk of interference with head movement during normal operation increases
Solution Approach 1:
The locking system is segmented into distinct functional zones: the locking element with its opening is positioned to engage the hook only when needed, while the motion transmission device and pendulum mechanism provide spatial separation during normal operation. This segmentation allows the locking function to be activated precisely when required without creating continuous interference with passenger head movement or tray table operation.
Solution Approach 2:
The locking element's position is dynamic rather than fixed. During normal operation, the locking element remains in a retracted or disengaged position that does not interfere with head movement. Upon impact detection through seat deformation, the locking element dynamically rotates about its pivot joint to engage the hook, providing reliable retention only when the hazard condition exists.
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 locking system effectively prevents the untimely opening of the tablet during seat deformation, reducing the risk of chin entrapment and associated injuries by maintaining the shelf in the stowed position during impacts.
Implementation Method 1
the motion transmission device includes a pendulum connected on one side to the latch and on the other side to the locking element via a pivot link
Implementation Method 2
in the event of deformation of the seat, said hook enters the opening in the locking element to hold the tablet in the stowed position
Data Source
Figure 1a~1b
Figure 1c~1d
Figure 2~3
AI summary
The invention mainly concerns a seat (10) comprising a backrest (11) carrying, on a rear face side, a tray table (15) that can be moved between a deployed position and a stowed position, - said tray table (15) comprising a latch (22) that can be moved between an unlocked position and a locked position, characterised in that said tray table (15) further comprises a locking system (27) configured to keep the tray table (15) in the stowed position following the deformation of said seat (10) during an impact.