Aircraft Seat Breakover Linkage for High-G Head Injury Mitigation
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Solution Overview
Problem
Conventional aircraft passenger seats face challenges in providing effective breakover mechanisms that minimize head injury during high G-force events while maintaining seat spacing efficiency and comfort, often requiring sacrificial components or excessive space between seats.
Innovation Solution
Aircraft passenger seats equipped with a dynamic breakover assembly using lower and upper links that synchronize seat motion during normal use, transitioning to a constrained over-center rotation during high G-force events, allowing the seat back to rotate forward past the upright position via elastic deformation of upper links.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a breakover mechanism is built into the seat back using sacrificial components, then head injury protection is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent changes the mechanical parameters of the link assembly, specifically designing the upper link with an over-center pivot geometry that transforms the breakover from a sacrificial component failure into a controlled geometric transformation. This allows the seat back to rotate forward past 90 degrees during high G-force events without requiring breakable bushings or shear pins, thus reducing device complexity while maintaining head injury protection.
Solution Approach 2:
The patent implements a dynamic breakover mechanism where the upper link transitions from a rigid constraint during normal use to an over-center rotation path during emergency deceleration. This dynamic behavior allows the system to adapt its mechanical response based on load conditions, providing head protection when needed while maintaining structural integrity and simplicity under normal operating conditions.
2Object-affected harmful factors
If passenger seats are spaced far apart to reduce head injury, then head injury protection is improved, but seating capacity and productivity decrease
Solution Approach 1:
The patent changes the mechanical response parameters of the seat back through the over-center link mechanism, enabling effective head injury protection through controlled forward rotation rather than increased seat spacing. This allows airlines to maintain higher seating density while meeting safety requirements for head injury protection during high G-force events.
3Stability of the object's composition
If the seat back is constrained to remain upright, then structural stability is improved, but the ability to protect passengers during high G-force events worsens
Solution Approach 1:
The patent implements a dynamic stability system where the lower links maintain the seat back in an upright position during normal use through synchronous rotation, but the upper link's over-center pivot geometry enables controlled forward breakover during high G-force events. This dynamic behavior allows the system to switch from a stable upright configuration to a protective forward rotation configuration based on loading conditions.
Solution Approach 2:
The patent designs the upper link with pre-configured over-center pivot geometry that automatically activates during emergency deceleration. This preliminary geometric configuration ensures that when high G-forces occur, the seat back is mechanically predisposed to rotate forward in a controlled manner, counteracting the harmful effect of passengers being thrown against the seat back before injury can occur.
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 solution provides controlled seat back rotation to reduce head injury risk during high G-force events, maintaining seat functionality and comfort without the need for additional space or sacrificial components, adhering to safety regulations.
Implementation Method 1
allowing the seat back to rotate forward past the position of the seat back when in the upright sitting position
Data Source
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AI summary
An aircraft passenger seat assembly (102) including spaced frame members and a pivotally attached seat bottom (106) and seat back (108) positioned between the spaced frame members. The seat bottom and the seat back are coupled to the frame members by upper and lower links (120, 122) positioned on opposite lateral sides of the seat back. During normal use of the seat, the upper and lower links rotate in a synchronous manner to articulate the seat between an upright sitting position and a reclined sitting position. During a dynamic event affecting the passenger seat, the lower links are fixed and the upper links are constrained to rotate over center of the seat back pivot axis to rotate the seat back forward past the upright sitting position.