Breathing Mask Control Assembly With Locked Normal Mode Switching

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Solution Overview

Problem

Existing aircraft crew member respirator masks face challenges in accurately selecting between emergency and normal modes due to asymmetry and lateral markings, leading to potential accidental mode selection during emergencies.

Innovation Solution

A control assembly with a locking/unlocking device that requires a deliberate action to switch from the default '100%' mode to the 'NORMAL' mode, preventing accidental selection by using a locking finger and projection system to ensure correct mode transition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the mode selection button is made asymmetrical with lateral markings to allow user distinction of rotation direction, then the ease of operation is improved, but the reliability deteriorates because users may still accidentally select the wrong mode during emergencies

Engineering Contradiction:
Improveease of mode selectionVSAvoidcorrect mode selection
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system performs a preliminary check by detecting the rotation direction of the mode selection button. Before allowing mode switching, the system verifies whether the rotation direction matches the intended mode selection, and only then activates the corresponding mode. This preliminary verification prevents accidental mode selection while maintaining ease of operation.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the mode selection button allows free rotation between positions for quick access, then the productivity is improved, but the reliability deteriorates due to risk of accidental mode changes

Engineering Contradiction:
Improvespeed of mode switchingVSAvoidprevention of accidental mode selection
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system incorporates feedback by detecting the rotation direction of the mode selection button and using this information to control mode switching. The detection unit monitors the rotation direction, and the control unit only permits mode changes when the rotation direction corresponds to the intended mode, providing immediate feedback that prevents accidental selections while allowing quick intentional switching.

Inventive Principle:
Principle #23Feedback

3Ease of operation

If the system provides clear visual markings and asymmetry for mode identification, then the ease of operation is improved, but the device complexity increases due to additional control mechanisms

Engineering Contradiction:
Improvemode identificationVSAvoidcontrol system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The invention replaces complex mechanical locking mechanisms with an electronic detection and control system. The detection unit senses the rotation direction of the mode selection button, and the control unit processes this information to enable or disable mode switching. This electronic approach achieves reliable mode selection prevention with simpler overall system architecture compared to traditional mechanical interlocks.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP3834890B1Control assembly for a breathing mask for an aircraft crew member
Publication Date: 2026.02.18 SAFRAN AEROSYST
  • EP3834890B1 patent drawingFigure 1
  • EP3834890B1 patent drawingFigure 2
  • EP3834890B1 patent drawingFigure 3

AI summary

The invention relates to a control assembly for an aircraft crew member's breathing mask, said assembly comprising a support (10), a mode selection button (20) pivotally mounted on the support between at least a first position (EMER), a second position (100%) and a third position (N), a regulator adapted to supply a breathing cavity in three operating modes depending on the position of the mode selection button and a locking-unlocking device comprising an operating member (31) capable of being moved between a locking position and an unlocking position; the locking position locking the rotation of the mode selection button from the second position (100%) to the third position (N), the unlocking position allowing the rotation of the mode selection button (20) from the second position (100%) to the third position (N).