Aircraft Cargo Door Rail-Guided Stowage for Usable Hold Space

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Solution Overview

Problem

Aircraft cargo doors that open inwardly, such as those on the Boeing 737, occupy a significant portion of the cargo space, reducing its usable height by about 30% and necessitating costly structural recalculations to convert to outward-opening doors, which is impractical.

Innovation Solution

A method and device that allows inward-opening cargo doors to be pivoted horizontally and then moved sideways or diagonally within the cargo space, using support frames and guide rails, enabling the door to be stored out of the way without altering the fuselage structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the cargo door opens inwardly, then the door can be supported and sealed along the entire periphery, but the door occupies significant cargo space and reduces usable height by about 30%

Engineering Contradiction:
Improvedoor sealing and supportVSAvoidcargo space
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The cargo door is transformed from a static inward-opening mechanism to a dynamic system that can pivot inward and then slide horizontally along guide rails. This dynamic movement allows the door to be stored horizontally within the cargo space rather than occupying vertical space, resolving the contradiction between reliable sealing and cargo volume utilization.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The door movement is extended from a single rotational dimension to a composite motion involving rotation followed by horizontal translation along guide rails. This dimensional change allows the door to be positioned horizontally within the cargo compartment, freeing up vertical cargo space while maintaining the inward-opening sealing advantage.

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

2Reliability

If the cargo door is made larger to compensate for space loss, then the door can be supported along the entire periphery, but the structural complexity and cost of reconstruction increase significantly

Engineering Contradiction:
Improvedoor supportVSAvoidstructural reconstruction
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The door support system is segmented into multiple functional components: the door itself, hinge mechanisms for inward rotation, and horizontal guide rails for sliding movement. This segmentation allows the door to maintain its original size and sealing design while adding a horizontal movement component that eliminates space occupation, avoiding the need for costly structural reconstruction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Horizontal guide rails are introduced as intermediary elements that enable the door to move from a vertical to a horizontal storage position. These guide rails act as mediators between the door and the cargo space, allowing the door to be stored efficiently without requiring modification of the fuselage structure or complete structural reconstruction.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Volume of moving object

If outward-opening cargo doors are used, then cargo space is maximized, but the fuselage and hinges must be constructed to withstand high forces at high altitudes, placing high demands on mechanical parts

Engineering Contradiction:
Improvecargo spaceVSAvoidfuselage and hinge construction
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

The door is designed with dynamic movement capabilities, pivoting inward for sealing and then sliding horizontally for storage. This dynamic approach allows the door to maintain the space-efficient inward-opening configuration while adding horizontal movement to eliminate space occupation, avoiding the need for reinforced fuselage and hinge construction required by outward-opening doors.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3941823B1Cargo door operating method and device
Publication Date: 2025.12.10 SCANDINAVIAN CARGOLOADING TECH AB
  • EP3941823B1 patent drawingFigure 1~2
  • EP3941823B1 patent drawingFigure 3~4
  • EP3941823B1 patent drawingFigure 5~6

AI summary

A method for operating a cargo door of an aircraft. The method comprises, opening the cargo door inwardly in relation to a cargo door opening by pivoting the cargo door to an open position adjacent a ceiling of a cargo space. The cargo door is supported by a door frame during opening of the cargo door. The method further comprises, moving the cargo door in relation to the door frame to a position wherein the cargo door opening is substantially free from the cargo door. The cargo door is supported by a support frame, moveable in relation to the door frame, during this movement. The invention also concerns a device for operating a cargo door of an aircraft.