Extendable Aircraft Restraint Reducing Head Impact Angle
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Solution Overview
Problem
Conventional lap seat belts in aircraft do not effectively prevent the upper torso of occupants from rotating forward during crashes, leading to potential head and neck injuries due to undue stress on the neck and head when the occupant's head strikes the forward structure.
Innovation Solution
The development of extendable restraint systems that lengthen during a dynamic event to reposition the occupant closer to an airbag or forward structure, reducing the angle of impact and distributing the force across the torso and head, thereby reducing the stress on the neck and head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lap seat belts are used to secure occupants, then the restraint system is simple and easy to operate, but the upper torso cannot be prevented from rotating forward during crashes, causing head and neck injuries
Solution Approach 1:
The restraint system transitions from a static conventional lap belt to a dynamic extending restraint that automatically lengthens during a crash event. The restraint includes an extendable portion with a retractor mechanism that remains compact during normal use but extends when subjected to crash forces, allowing the occupant's torso to move forward in a controlled manner to reduce impact angle with the airbag or forward structure.
Solution Approach 2:
The extending restraint mechanism is nested within the conventional lap belt structure. The retractor and extendable portion are integrated into the existing restraint system, allowing the complex extending mechanism to be contained within the simple lap belt configuration during normal operation, thereby maintaining ease of operation while adding protection capability.
2Reliability
If the occupant's torso is restrained too tightly to prevent forward movement, then forward rotation is limited, but the impact force with the airbag or monument increases, causing greater stress on the head and neck
Solution Approach 1:
The extending restraint provides beforehand cushioning by allowing controlled forward movement of the occupant's torso before impact occurs. The extendable portion acts as a cushion that absorbs some of the impact energy and reduces the force transmitted to the head and neck during the crash event, rather than allowing rigid restraint that transmits full impact force.
Solution Approach 2:
The restraint system changes the parameter of restraint force dynamically during a crash event. During normal operation, the restraint maintains standard tension. During a crash, the extendable portion activates to change the restraint characteristics, allowing increased forward movement and reducing the peak impact force on the occupant's head and neck while still providing adequate restraint.
Data Source
AI summary
Various embodiments of vehicle occupant safety systems having extendable restraints for use with, for example, airbags are described herein. In one embodiment, for example, the disclosed technology includes a 2-point occupant restraint that secures an occupant in an aircraft seat. In this embodiment, the aircraft seat is positioned in a seating area that includes a forward monument housing a stowed airbag. In the event of a crash or other significant dynamic event that causes, for example, a rapid deceleration of the aircraft above a preset magnitude, the airbag deploys between the occupant and the monument as the dynamic forces cause the occupant to pitch forward. The forward momentum of the occupant's body creates a significant tension load in the 2-point restraint, which causes the restraint to extend by a preset amount, thereby allowing the occupant to move forward in the seat more than the occupant would have moved had the occupant been wearing a conventional, non-extending 2-point restraint. Although the occupant is allowed to move forward, the occupant remains secured to the extended restraint by means of non-extending webbing that is secured around the waist of the occupant. Allowing the occupant to move forward in this manner enables the occupant's upper torso to impact the airbag at a reduced or otherwise more favorable angle. This can reduce both the speed and the angle at which the occupant's head impacts the airbag, thereby reducing the likelihood of injury.