Directional Headgear Lock for Automatic Micro-Adjustment

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Solution Overview

Problem

Existing respiratory therapy systems face challenges with interface assemblies that require user interaction for adjustment, leading to misuse or mis-adjustment, and struggle with micro-adjustments due to difficult and time-consuming mechanisms.

Innovation Solution

A directional lock mechanism with a housing, sleeve, and lock element that automatically adjusts to the user's head size, transitioning between elastic and locked modes to provide quick and convenient micro-adjustments, using a rack and pinion mechanism or rollers for smooth operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a hook-and-loop or similar fastener adjustment mechanism is used, then the headgear can be adjusted for different head sizes, but the mechanism is difficult and time-consuming for micro-adjustments and prone to misuse

Engineering Contradiction:
Improveadjustment rangeVSAvoidmicro-adjustment ease
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent replaces the traditional hook-and-loop fastener system with a ratchet and pawl mechanism that provides one-way adjustment. The ratchet teeth engage with the pawl to prevent backward movement, enabling easy micro-adjustments in one direction while maintaining the ability to accommodate different head sizes.

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

Solution Approach 2:

The adjustment mechanism is designed to be self-locking through the ratchet-pawl interaction, eliminating the need for precise user skill. The system automatically maintains the adjusted position without requiring user intervention to prevent slippage or misuse.

Inventive Principle:
Principle #25Self-service

2Adaptability or versatility

If a traditional adjustment mechanism is used, then the headgear can be adjusted, but over-tightening or mis-adjustment occurs due to lack of control

Engineering Contradiction:
Improveadjustment capabilityVSAvoidadjustment accuracy
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

Instead of allowing adjustment in both directions with a reversible mechanism, the patent uses a unidirectional ratchet system that permits adjustment in one direction (loosening) while automatically locking in the other direction (tightening). This inversion of the traditional reversible adjustment approach prevents over-tightening and mis-adjustment.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The ratchet mechanism预先 prevents over-tightening by mechanically blocking any adjustment beyond the ratchet's engagement point. The pawl engages with the ratchet teeth to create a hard stop that prevents excessive tightening forces from damaging the interface or causing mis-adjustment.

Inventive Principle:
Principle #9Preliminary anti-action

3Reliability

If the headgear uses a seal to deliver pressurized air, then therapy effectiveness is improved, but a blow-off force pushes the mask off the face requiring constant restraint

Engineering Contradiction:
Improvetherapy effectivenessVSAvoidblow-off force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The headgear uses an elastic strap material that dynamically adapts to the forces applied. The elastic properties allow the strap to stretch under blow-off force and then recoil, providing continuous restraint that adjusts to varying pressure conditions during therapy while maintaining the seal effectiveness.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The headgear arrangement creates a counterbalancing force through the elastic strap tension that opposes the blow-off force generated by the pressurized air seal. This counterforce continuously restrains the mask against the face, preventing displacement while allowing the seal to function effectively.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Data Source

PatentEP4458396B1Directional lock for interface headgear arrangement
Publication Date: 2026.02.04 FISHER & PAYKEL HEALTHCARE LTD
  • EP4458396B1 patent drawingFigure 1
  • EP4458396B1 patent drawingFigure 2~4
  • EP4458396B1 patent drawingFigure 5A~5B

AI summary

A directional lock or a headgear or interface assembly comprising one or more directional locks that include a catch arrangement for initiating or assisting in movement of a lock member of the direction lock. In some configurations, the catch arrangement assists movement of the lock member in only a portion of a range of travel of the lock member. In some configurations, the directional lock comprises a housing and a sleeve and the catch arrangement comprises a catch arm carried by the sleeve. The catch arm includes a catch end that contacts the lock member, which can be a lock washer in some configurations.