Double-Curved Aircraft Door Locking Stops Alignment

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Solution Overview

Problem

Existing double curvature aircraft doors face complexities in locking mechanisms due to the need for specific parts and complex geometries, leading to increased manufacturing costs, maintenance challenges, and potential risks during aircraft accidents.

Innovation Solution

The aircraft door features an optimized arrangement of opening and supervisory stops, with isobarycentres aligned in perpendicular planes and contact areas oriented to align with the pressure result vector, allowing for a single reference for each side edge and eliminating parasitic efforts during pressurization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional locking means with multiple different stops are used for double-curved aircraft doors, then the door can maintain proper pressure in flight, but the manufacturing complexity and costs increase significantly

Engineering Contradiction:
Improvepressure maintenanceVSAvoidlocking means complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by designing a single type of stop that can be used at multiple locations on the door. Instead of requiring different stops for different lateral edges, the invention uses identical stops that can be positioned at various locations, reducing part variety while maintaining the ability to handle pressurization forces effectively.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention merges the functionality of multiple different stops into a single standardized stop design. By combining the roles of opening stops and frame stops into a unified component with standardized geometry, the patent reduces manufacturing complexity while preserving the pressure-maintaining function through strategic positioning.

Inventive Principle:
Principle #5Merging (Combining)

2Strength

If multiple different stops are used at different lateral edges, then the door can be optimized for mass and strength, but the maintenance costs increase due to numerous part references

Engineering Contradiction:
Improvemechanical strengthVSAvoidmaintenance cost
Core Design Contradiction:
StrengthVSEase of repair

Solution Approach 1:

The patent implements universality by creating a single standardized stop design that can be used at all lateral edges of the door. This eliminates the need to maintain multiple different stop references, significantly reducing maintenance and repair costs while still providing adequate mechanical strength through proper positioning and design.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Force

If stops are arranged with reaction forces parallel to the pressure resultant, then the door can handle pressurization forces, but the manufacturing precision requirements increase due to specific geometry needs

Engineering Contradiction:
Improvepressure reaction forceVSAvoidcontact area orientation
Core Design Contradiction:
ForceVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by modifying the orientation and positioning parameters of the stops. Instead of requiring precise alignment for parallel reaction forces, the invention uses a standardized stop geometry with specific angular orientations that simplify manufacturing while still achieving the necessary force distribution and pressure reaction characteristics.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4188796B1Double-curved aircraft door with optimised locking means
Publication Date: 2025.04.30 LATECOERE
  • EP4188796B1 patent drawingFigure 1
  • EP4188796B1 patent drawingFigure 2
  • EP4188796B1 patent drawingFigure 3

AI summary

Double-curved aircraft door comprising pairs of stops in contact over a contact area. The isobarycentre (31A) of each contact area of a first lateral edge is substantially arranged in a first plane perpendicular to the longitudinal axis (21) and the same applies to a second lateral edge. For each contact area, the normal to the contact area passing through its isobarycentre (31A, 31B) substantially passes through the axis (41) of a medium cylinder (42). For each contact area, the normal to the contact area passing through its isobarycentre (31A, 31B) forms a deflection angle with a plane perpendicular to the longitudinal axis (21), the deflection angles of all the contact areas being equal.