Articulated Aircraft Door Hinge for Low-Profile Door Positioning

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Solution Overview

Problem

Conventional hinge assemblies for translating-motion-type aircraft doors are bulky and occupy significant space within the fuselage, limiting availability for other purposes such as stowage or seating, due to their mechanical linkages that control door orientation.

Innovation Solution

An articulated hinge assembly with a low-profile design that includes an articulated hinge arm and a linkage assembly to control the door's movement along a programmed path, minimizing space usage and incorporating a drive assembly and emergency power assist for controlled door opening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a mechanical linkage is used to control door movement, then door positioning control is improved, but space occupancy increases

Engineering Contradiction:
Improvedoor positioning controlVSAvoidspace occupancy
Core Design Contradiction:
Ease of operationVSVolume of moving object

Solution Approach 1:

The patent merges the hinge arm and mechanical linkage into a single integrated articulated hinge assembly. The first and second hinge members are pivotably coupled to form an articulated structure that combines the functions of both the hinge (supporting door weight) and the linkage (controlling door position), eliminating the need for separate bulky linkage components extending into the fuselage.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The articulated hinge assembly nests the second hinge member within the envelope of the first hinge member when the door is closed, creating a compact configuration. The hinge members are arranged so that the second hinge member is positioned inside or adjacent to the first hinge member's volume, minimizing space occupancy while maintaining full functionality.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If a bulky mechanical linkage is used, then door movement control is improved, but availability of interior space is reduced

Engineering Contradiction:
Improvedoor movement controlVSAvoidinterior space availability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The hinge assembly employs an articulated structure with pivotable coupling between hinge members that allows dynamic adjustment of the assembly's configuration. The elbow joint enables the hinge members to articulate through a range of motions, adapting to different door positions (closed, opening, open) while maintaining compact packaging within the hinge arm envelope.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent utilizes three-dimensional spatial arrangement of the articulated hinge members to achieve compactness. By arranging the hinge members in a folded configuration within the hinge arm's volume and using vertical articulation at the elbow joint, the design minimizes the horizontal extension into the fuselage while maintaining full door control functionality.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

The articulated hinge assembly provides a low-profile solution that allows for efficient use of fuselage space while ensuring controlled and programmed door movement, accommodating emergency power assistance for safe and efficient door operation.

Implementation Method 1

The hinge also translates the door forward to provide a clear opening into the aircraft as the door swings away from the body

Methodology Applied
Scientific EffectMechanical linkage:

Implementation Method 2

an articulated hinge arm having a first hinge member and a second hinge member pivotably coupled to the first hinge member at an elbow

Methodology Applied
Scientific EffectPivotable coupling:

Implementation Method 3

The hinge linkage assembly controls movement of the first hinge member and the second hinge member relative to each other and relative to the fuselage fitting

Methodology Applied
Scientific EffectMechanical control linkage:

Implementation Method 4

The door linkage assembly is coupled to the articulated hinge arm and the door to control positioning of the door relative to the second hinge member

Methodology Applied
Scientific EffectMechanical positioning linkage:

Data Source

PatentEP4431384B1Articulated hinge assembly for an aircraft door
Publication Date: 2026.05.06 THE BOEING CO
  • EP4431384B1 patent drawingFigure 1
  • EP4431384B1 patent drawingFigure 2~3
  • EP4431384B1 patent drawingFigure 4

AI summary

An articulated hinge assembly for connecting a door to a fuselage of an aircraft includes an articulated hinge arm having a first hinge member pivotably coupled to a second hinge member at an elbow. A fuselage fitting is pivotably coupled to a fuselage bracket and a door fitting is pivotably coupled to a door bracket of the door. The articulated hinge arm is movable from a collapsed position to an expanded position to move the door from a door closed position to a door open position. The articulated hinge assembly includes a linkage assembly coupled to the articulated hinge arm, the fuselage fitting and the door fitting controlling movement of the first hinge member and the second hinge member relative to each other and relative to the fuselage fitting. The linkage assembly controls positioning of the door.