Aircraft Door Connection Assembly Virtual Pivot
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Solution Overview
Problem
Existing aircraft door connection assemblies, particularly for emergency exits, require significant wall thickness due to gooseneck hinge members, which can lead to protrusions into the cabin and are not suitable for aircraft with thinner walls, necessitating a more compact and efficient solution.
Innovation Solution
A connection assembly that includes a main hinge pivotally connected to the fuselage and a link assembly with non-parallel links, allowing the door to move upward and inward without moving the main hinge, and subsequently pivot around a virtual pivot point outside the aircraft, minimizing space and volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gooseneck hinge members are used to connect the door to the fuselage, then the door can be pivotally connected and provide emergency exit functionality, but the wall thickness must be increased to accommodate the hinge members and their gooseneck portions
Solution Approach 1:
The connection assembly is divided into separate functional components: a main hinge member pivotally connected to the fuselage, and a link assembly with multiple links (first link, second link, third link) that connect the door to the main hinge. This segmentation allows each component to be optimized independently, enabling the use of thinner wall material while maintaining connection reliability through a distributed structural arrangement rather than a monolithic gooseneck design.
Solution Approach 2:
The patent introduces a virtual pivot point located outside the aircraft fuselage, transforming the door's rotation from a conventional in-plane pivot to an out-of-plane rotation. This dimensional change allows the door to pivot around a point external to the fuselage wall, eliminating the need for thick wall construction to accommodate internal hinge mechanisms while maintaining proper door rotation functionality.
2Reliability
If gooseneck hinge members with inward protrusions are used, then the door can be securely attached to the fuselage, but protrusions must be formed in the inner wall to accommodate the hinge members
Solution Approach 1:
The patent extracts the protruding gooseneck portion from the hinge member design and relocates it to form part of the link assembly structure. Instead of the gooseneck protrusion being contained within the fuselage wall thickness, it is integrated into the external link assembly configuration, eliminating the need to form protrusions in the inner wall while maintaining secure door attachment.
Solution Approach 2:
The link assembly acts as an intermediary mechanism between the main hinge member and the door, distributing the connection forces and moments through multiple links with specific geometric relationships. This intermediary structure eliminates the need for direct internal wall modifications by providing an external transmission path that achieves secure attachment without inner wall protrusions.
3Volume of stationary object
If a compact connection assembly is designed to reduce volume, then cabin protrusion is minimized and thinner walls can be used, but the door's movement path and pivot mechanics become more complex
Solution Approach 1:
The patent employs a dynamic movement sequence where the door first translates upward and inward along a predetermined path, then pivots around a virtual pivot point located outside the aircraft. This two-stage dynamic motion is achieved through the geometric configuration of the link assembly, where non-parallel link axes create the necessary motion transformation. While the motion path is more complex than simple rotation, the mechanism itself is compact and integrates smoothly into the door structure.
Data Source
AI summary
A system for opening a door of an aircraft includes a connection assembly adapted to connect the door to a fuselage section of the aircraft. The connection assembly includes a main hinge pivotally connected to the fuselage section and a link assembly connecting the door to the main hinge and pivotally connected to the fuselage section, the link assembly including one member slidingly and pivotally connected to the door. The system also includes a latch mechanism between the door and the main hinge, the latch mechanism being adapted to be actuated. The system is adapted to move the door upwardly and inwardly along a predetermined path without moving the main hinge through movement of the latch mechanism and, subsequently, to pivot the door around a virtual pivot point located outside of the aircraft by moving the main hinge once the door has reached an end of the predetermined path.