Rotating Door Stop Fitting for Aircraft Cabin Doors
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Solution Overview
Problem
Aircraft cabin doors face complexity in kinematics and weight due to rigidly fixed stop fittings, requiring complex mechanisms for movement and sealing, which complicates emergency opening and increases costs and weight, while existing cargo door concepts are not suitable for cabin doors due to space and safety concerns.
Innovation Solution
A load transfer interface with rotatable door stop fittings that allow single-phase opening and closing, simplifying kinematics and actuation, and enabling high-load transfer with reduced weight and complexity, using a rotating arm and bearings for low-friction movement, and eliminating the need for vertical door movement and weight compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigidly fixed stop fittings are used to transfer pressure loads, then load transfer capability is improved, but device complexity and weight increase due to complex kinematics and sealing mechanisms
Solution Approach 1:
The stop fitting is designed to rotate about an axis during door opening/closing operations, transitioning from a static fixed position to a dynamic rotating mechanism. This rotational movement allows the stop fitting to naturally follow the door's motion path, eliminating the need for complex sealing mechanisms and reducing kinematic complexity while maintaining load transfer capability through the rotating connection.
2Strength
If rigidly fixed stop fittings are used to transfer pressure loads, then load transfer capability is improved, but weight increases due to complex mechanisms
Solution Approach 1:
The rotating stop fitting eliminates the need for heavy complex sealing mechanisms and multiple moving parts required by fixed designs. The simple rotational joint uses minimal material while providing sufficient strength for load transfer, significantly reducing the overall weight of the door assembly compared to rigidly fixed stop fittings with associated complex mechanisms.
3Reliability
If complex mechanisms are used for door movement and sealing, then emergency opening safety is improved, but ease of operation deteriorates
Solution Approach 1:
The rotating stop fitting provides a natural, intuitive opening motion that follows the door's rotational path, making the operation simpler and more direct compared to complex multi-phase mechanisms. The rotation automatically engages and disengages the stop fitting from the door frame, maintaining safety through reliable load transfer while improving ease of operation through straightforward rotational movement.
4Strength
If rigidly fixed stop fittings are used, then manufacturing precision requirements increase due to tolerance compensation needs
Solution Approach 1:
The rotating stop fitting acts as a self-adjusting mechanism that can accommodate manufacturing tolerances and misalignments through its rotational degree of freedom. During door assembly, the rotation allows the stop fitting to naturally find its correct position, reducing the stringency of manufacturing precision requirements compared to rigidly fixed stop fittings that require precise pre-alignment and tolerance compensation features.
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 solution simplifies door opening and closing, reduces weight and costs, enhances safety, and allows for advanced composite material usage, improving the design and functionality of aircraft cabin doors by enabling efficient high-load transfer and simplified emergency opening.
Implementation Method 1
using a rotating arm and bearings for low-friction movement
Data Source
AI summary
A load transfer interface for a vehicle door that comprises an outer skin and at least one beam that is connected to the outer skin, wherein the outer skin and the at least one beam define a vehicle door plane, the load transfer interface comprising at least one door stop fitting that is provided to transfer pressure loads from the vehicle door to an associated vehicle structural frame, the at least one door stop fitting being provided for rotation in an associated rotation plane, wherein the associated rotation plane is at least approximately parallel to the vehicle door plane. The invention is further related to an aircraft cabin door having such a load transfer interface, as well as to an aircraft having such an aircraft cabin door.