Aircraft Cargo Door Seal Lap Joint for Modular Replacement

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Solution Overview

Problem

Conventional aircraft cargo door seals require complete replacement due to integral contiguous seamless structures, leading to high costs and aircraft grounding time, especially in military cargo aircraft, and pose challenges in maintaining pressurization and electromagnetic interference resistance.

Innovation Solution

Aircraft door seals with non-integral partitioned sections joined by a lap joint assembly, comprising a lap joint member and interior support spigot, allowing for easier installation and replacement, and maintaining seal integrity under pressure and electromagnetic interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional integral contiguous seamless seal structures are used, then seal integrity and pressurization resistance are improved, but maintenance complexity and replacement time increase significantly

Engineering Contradiction:
Improveseal integrityVSAvoidreplacement time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The seal is divided into multiple discrete modular sections that can be independently replaced. Each section contains sealing elements that can be accessed and replaced without removing the entire seal or the door, thereby reducing replacement time while maintaining overall seal integrity through the modular design.

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If conventional integral contiguous seamless seal structures are used, then electromagnetic wave shielding effectiveness is improved, but maintenance cost and aircraft grounding time increase

Engineering Contradiction:
Improveelectromagnetic interference resistanceVSAvoidmaintenance cost
Core Design Contradiction:
Object-affected harmful factorsVSEase of repair

Solution Approach 1:

The seal is segmented into modular sections that can be independently replaced. Each section maintains electromagnetic shielding capabilities through its design, allowing localized replacement of damaged sections without replacing the entire seal system, thereby reducing maintenance costs and aircraft grounding time while preserving overall electromagnetic interference resistance.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If non-integral partitioned seal sections with lap joints are used, then ease of installation and replacement is improved, but joint reliability and pressurization resistance may be compromised

Engineering Contradiction:
Improveease of replacementVSAvoidjoint reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The lap joint assembly incorporates nested sealing elements where inner sealing members are positioned within outer sealing structures. This nested configuration creates multiple sealing interfaces at the joints between modular sections, ensuring reliable pressurization resistance while maintaining the ease of modular installation and replacement.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The lap joint assembly merges multiple sealing functions into a single integrated component that combines overlapping seal sections with embedded sealing elements. This unified design ensures continuous sealing across joint boundaries while allowing individual modular sections to be easily replaced without affecting overall joint reliability.

Inventive Principle:
Principle #5Merging (Combining)

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

Facilitates easier and cost-effective maintenance of aircraft cargo door seals, reducing downtime and maintaining pressurization and electromagnetic interference resistance.

Implementation Method 1

Each of the door seal sections may be a hollow profiled door seal defining the interior space and formed of an elastomeric sealing material

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

withstand disengagement without affecting the pressurization and/or entry of electromagnetic waves from high intensity radiated fields (HIRF)

Methodology Applied
Scientific EffectElectromagnetic shielding: Faraday Cage

Data Source

PatentEP4289722B1Aircraft door seals and lap joint junction seal assemblies thereof
Publication Date: 2025.07.30 EMBRAER SA
  • EP4289722B1 patent drawingFigure 1~2
  • EP4289722B1 patent drawingFigure 2A
  • EP4289722B1 patent drawingFigure 3

AI summary

Aircraft door seals, especially door seals for aircraft cargo doors, include individual door seal sections joined together by a lap joint assembly. The door seal sections may have abutted ends establishing a seal junction, and a lap joint junction seal assembly to sealingly join the abutted ends of the door seal sections, wherein the lap joint junction seal assembly includes (i) a lap joint member having a lap joint base and a lap joint shelf extending from the lap joint base and sealingly engaged with a lower surface of the door seal sections over the seal junction, and (ii) an interior support spigot inserted within the interior space of each of the door seal sections at the abutted ends thereof. Each of the door seal sections may be a hollow profiled door seal defining the interior space and formed of an elastomeric sealing material.