Seatback energy management system
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Solution Overview
Problem
Conventional passenger seatback energy dissipation solutions are limited in adjustability and do not effectively integrate video monitors with energy dissipation features, posing challenges to occupant safety during head impacts, as they may not meet Head Injury Criterion (HIC) and delethalization requirements, and can result in monitor delamination.
Innovation Solution
A video monitor assembly with a bezel assembly coupled to the passenger seatback using low load fasteners that shear under impact and high load fasteners that withstand forces, allowing the monitor to pivot and absorb energy while preventing delamination, featuring low load fasteners made of nylon and high load fasteners made of steel strategically positioned around the monitor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional energy dissipation features (metallic brackets with shear area or shear bolts) are used in seatback, then energy dissipation is achieved, but adjustability is limited and monitor integration is difficult
Solution Approach 1:
The fastening system is segmented into two distinct types: low load fasteners (nylon) positioned at outer attachment tabs and high load fasteners (steel) positioned at inner attachment tabs. This segmentation allows each fastener type to perform its specific function - low load fasteners fail first to allow controlled energy dissipation and monitor pivoting, while high load fasteners remain intact to maintain structural integrity. This resolves the contradiction by providing adjustable energy dissipation characteristics without requiring complex mechanical structures.
Solution Approach 2:
Different fastener materials and strengths are applied at different locations on the bezel assembly. The low load nylon fasteners are placed at outer attachment tabs where energy dissipation is needed, while high load steel fasteners are placed at inner attachment tabs where structural strength is required. This local differentiation allows the system to achieve both energy dissipation and structural integrity without uniform complexity throughout the entire assembly.
2Strength
If video monitors are mounted in seatback with rigid fastening, then structural integrity is maintained, but head impact energy cannot be effectively dissipated and HIC requirements may not be met
Solution Approach 1:
The fastening system transitions from a static rigid connection to a dynamic system that changes behavior under load. During normal operation, all fasteners maintain the monitor in a fixed position. During head impact, the low load fasteners fail first, allowing the monitor to pivot dynamically and dissipate energy, while high load fasteners maintain structural connection. This dynamic response resolves the contradiction by providing both structural integrity and impact energy dissipation.
Solution Approach 2:
The design incorporates low load fasteners that are pre-configured to fail at a predetermined load threshold before the high load fasteners. This beforehand cushioning mechanism ensures that during head impact, energy is dissipated through controlled fastener failure and monitor pivoting before the force can be transmitted to the occupant's head, thereby meeting HIC requirements while maintaining structural integrity through the remaining high load fasteners.
3Adaptability or versatility
If video monitors are mounted in seatback, then entertainment functionality is provided, but monitor display may delaminate upon impact creating sharp edges
Solution Approach 1:
The low load fasteners are pre-configured to fail first during impact, creating a preliminary anti-action that allows the monitor to pivot and dissipate energy before delamination can occur. By controlling the failure mode of the fastening system, the design prevents the uncontrolled forces that would cause display delamination and sharp edge creation, thereby protecting occupant safety while maintaining entertainment functionality.
4Object-affected harmful factors
If low load fasteners are used to allow energy dissipation, then HIC values are met, but monitor attachment strength is reduced
Solution Approach 1:
The fastening system uses local quality differentiation by placing low load nylon fasteners at outer attachment tabs for energy dissipation and high load steel fasteners at inner attachment tabs for structural strength. This localized assignment of different material properties allows the system to simultaneously achieve both energy dissipation (reducing HIC) and maintain monitor attachment strength through the high load fasteners that remain intact during impact.
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 effectively manages head impact energy within allowable HIC values, preventing monitor delamination and ensuring occupant safety by allowing controlled energy dissipation and pivot movement during impacts, while minimizing additional weight and cost.
Implementation Method 1
the low load fasteners are configured to fail or shear from a force applied to the monitor during a head impact
Implementation Method 2
the high load fasteners are configured to withstand the force applied to the monitor during the head impact
Implementation Method 3
allowing the monitor to pivot and absorb energy while preventing delamination
Data Source
AI summary
Described are video monitor assemblies (10) including a bezel assembly (16) coupled to a passenger seatback (12), wherein the bezel assembly includes a monitor (30) and a bezel (28), the monitor coupled to the bezel via low load fasteners (44) and high load fasteners (46), wherein the low load fasteners (44) are configured to fail or shear from a force applied to the monitor (30) during a head impact, and the high load fasteners (46) are configured to withstand the force applied to the monitor during the head impact.