Saloon Lavatory Door Lock Assembly with 180-Degree Egress

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Solution Overview

Problem

Airplane lavatory doors are uncomfortable and unpleasant for users due to inadequate locking mechanisms, which fail to provide reliable closure and emergency egress options.

Innovation Solution

A saloon-type lavatory door assembly with a hinge and lock system that includes alternating hinge strips forming a hinge band, a four-bar linkage mechanism, and a detent assembly, allowing 180-degree rotation for easy egress and self-closing functionality, utilizing synthetic polymer fabrics and magnets for efficient operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional locking mechanism is used, then the door can be secured, but the user cannot easily escape in emergency situations

Engineering Contradiction:
Improvelocking reliabilityVSAvoidemergency egress
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The lock assembly automatically unlocks when the door is pried open with sufficient force, eliminating the need for manual intervention during emergency situations. The system serves itself by detecting the emergency condition (forced entry) and automatically releasing the locking mechanism.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The locking mechanism transitions from a static locked state to an unlocked state dynamically in response to applied force. The system adapts its behavior based on the force applied, remaining locked during normal use but automatically unlocking when emergency force is detected.

Inventive Principle:
Principle #15Dynamics

2Reliability

If a complex locking mechanism is used, then security is improved, but the device complexity increases

Engineering Contradiction:
Improvedoor securityVSAvoidlocking mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the traditional key and complex locking components, extracting only the essential blocking member that prevents door opening. This simplifies the mechanism while maintaining security through the automatic release feature.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces complex mechanical locking systems with a simpler blocking member and spring assembly. The automatic release mechanism uses mechanical force detection rather than complex interlocking components, reducing overall system complexity.

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

3Ease of operation

If a saloon-type door with 180-degree rotation is used, then ease of egress is improved, but the hinge mechanism complexity increases

Engineering Contradiction:
Improvedoor egressVSAvoidhinge mechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The hinge system is divided into multiple hinge strips that can be independently positioned along the door edge. This segmentation allows the door to achieve 180-degree rotation capability while distributing the mechanical complexity across multiple simple, identical components rather than one complex hinge.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The hinge strips can be positioned at different locations along the door edge, changing the geometric parameters of the hinge system to achieve the desired 180-degree rotation range. This allows easy egress without requiring an overly complex mechanical hinge design.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3553263B1Lock assembly in particular for saloon-type doors
Publication Date: 2021.06.30 SAFRAN CABIN INC
  • EP3553263B1 patent drawingFigure 1
  • EP3553263B1 patent drawingFigure 2
  • EP3553263B1 patent drawingFigure 3

AI summary

A saloon-type door assembly that includes left and right door assemblies that each include a frame adapter having a curved inner surface with a first apex, a front portion and a rear portion, a door adapter that includes a curved outer surface with a second apex a front portion and a rear portion, a door panel associated with the door adapter, at least one front hinge strip secured along a front hinge strip path, and at least one rear hinge strip that is secured along a rear hinge strip path. The front hinge strip path extends from the front portion of the curved outer surface of the door adapter to the rear portion of the curved inner surface of the frame adapter. The rear hinge strip path extends from the rear portion of the curved outer surface of the door adapter to the front portion of the curved inner surface of the frame adapter. The door panels are movable between a front open position, a closed position and a rear open position.