Aircraft Oxygen Mask Lanyard Segmentation to Prevent Entanglement
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Solution Overview
Problem
Emergency oxygen devices in aircraft face issues with lanyard entanglement and the reliability of oxygen masks being presented to passengers at the correct level, especially when multiple masks are supplied from a single chemical oxygen generator, leading to potential malfunction in emergency situations.
Innovation Solution
The emergency oxygen device features a mechanical connection system with a fixation element and elongate connecting elements that reduce lanyard length, prevent entanglement, and ensure safe, reliable activation of the chemical oxygen generator by allowing the oxygen masks to accelerate and apply sufficient force during free fall, facilitating precise positioning and easy mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a significant length of lanyard is provided to allow the oxygen mask to be pulled down to a predetermined level, then the mask can be easily reached by any passenger, but the lanyard may entangle and produce loops, slings or meshes, causing the mask not to be properly presented to the passenger
Solution Approach 1:
The lanyard is divided into two separate parts: a first lanyard connecting the oxygen mask to the activation unit, and a second lanyard connecting the oxygen mask to the casing. This segmentation allows each lanyard to be shorter and perform its specific function without entanglement, while together they achieve the required mask positioning and activation reliability
Solution Approach 2:
The oxygen mask itself acts as an intermediary element that connects the two separate lanyards. The first lanyard attaches to the activation unit and the second lanyard attaches to the casing, with the mask serving as the central connection point that transfers the pulling force to activate the chemical oxygen generator
2Device complexity
If multiple oxygen masks are supplied from one single chemical oxygen generator to save costs and weight, then the device complexity is reduced, but the risk of lanyard entanglement increases and may hinder proper function
Solution Approach 1:
Each oxygen mask is equipped with its own separate first and second lanyards, creating independent activation paths. This segmentation ensures that entanglement of one mask's lanyards does not affect the activation capability of other masks, maintaining system reliability while sharing a common oxygen generator
Solution Approach 2:
The dual lanyard configuration (first lanyard for activation, second lanyard for positioning) serves multiple functions simultaneously: it enables reliable activation of the shared oxygen generator, ensures proper mask positioning at predetermined levels, and prevents entanglement issues that would compromise system reliability
3Device complexity
If the oxygen mask is connected directly to the activation unit via a single lanyard, then the activation mechanism is simple, but the mask cannot be reliably positioned at a predetermined level while preventing entanglement
Solution Approach 1:
The connection system is segmented into two distinct lanyards with specific functions: the first lanyard handles activation force transmission to the firing pin mechanism, while the second lanyard controls mask positioning relative to the casing. This functional segmentation achieves precise positioning without requiring complex single-lanyard mechanisms
Solution Approach 2:
The oxygen mask serves as an intermediary that connects the two lanyards at specific attachment points. This intermediary role allows the system to achieve precise positioning control through the second lanyard's connection to the casing, while the first lanyard maintains a direct mechanical path to the activation unit
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
This design reduces the risk of entanglement, ensures reliable oxygen mask deployment at the correct level, and simplifies the activation process, enhancing the safety and functionality of the emergency oxygen system by using a dual mechanical connection system and a single elongate element for load transfer.
Implementation Method 1
A chemical oxygen generator comprises one or more substances which are able to conduct a chemical reaction producing oxygen. This chemical reaction must be started in an emergency situation to provide said oxygen to the passenger. It is known to initiate said chemical reaction by a starter unit which is activated by a mechanical pulling force exerted by the passenger via the oxygen mask. The starter unit then includes means for a short exothermic reaction sufficient to initiate the chemical reaction which thereafter is conducted as exothermic, self-sustaining reaction.
Implementation Method 2
The emergency oxygen device features a mechanical connection system with a fixation element and elongate connecting elements that reduce lanyard length, prevent entanglement, and ensure safe, reliable activation of the chemical oxygen generator by allowing the oxygen masks to accelerate and apply sufficient force during free fall
Data Source
Figure 1~2
Figure 3~4
AI summary
Emergency oxygen device for aircraft passengers comprising an oxygen source (10), an activation unit, at least an oxygen mask (20) and a mechanical activation assembly for activating the activation unit. According to the invention the activation unit is activated by a mechanical force exerted onto an activation element of the activation unit and the mechanical activation assembly comprises for each oxygen mask (20) a first mechanical connection (22) from the activation element to a fixation element (30) releasably mounted to said emergency oxygen device and a second mechanical connection (21) from said fixation element (30) to said oxygen mask (20).