Aircraft Door Handle Locking for Lateral Stop Escape
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing aircraft door mechanisms face issues with the desynchronization of door movements due to the handle's rotation during the circular translation phase, potentially preventing re-closing or causing the door to strike the fuselage, especially in systems with lateral escape stops.
Innovation Solution
A locking mechanism using a pawl and concave/convex ramp pair to immobilize the handle in its end position during the circular translation phase, ensuring it remains fixed relative to the door, eliminating the need for moving parts and reducing wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the handle is allowed to rotate freely during the circular translation phase, then the door mechanism has simpler structure and easier operation, but the door risks becoming desynchronized, potentially preventing re-closing or causing the door to strike the fuselage
Solution Approach 1:
The locking mechanism is pre-configured with the pawl and ramp geometry designed to automatically engage at the precise moment the handle reaches its end position. The ramp's inclined surface is positioned such that it contacts the pawl exactly when the handle completes its rotation, preventing any subsequent movement during the circular translation phase without requiring active control systems.
Solution Approach 2:
The pawl-ramp mechanism acts as an intermediary between the handle and the door mechanism. This intermediate locking component translates the handle's rotational position into a mechanical constraint, ensuring that the handle remains fixed relative to the door during circular translation while allowing free rotation during the escape phase.
2Reliability
If a locking mechanism is introduced to block the handle during circular translation, then door synchronization and reliability are improved, but the device complexity increases
Solution Approach 1:
The locking function is extracted as a separate, dedicated pawl-ramp mechanism rather than being integrated into the main door actuation system. This modular approach allows the locking function to be added without fundamentally redesigning the existing door mechanism, maintaining simplicity while improving reliability.
Solution Approach 2:
The locking mechanism uses simple, easily manufactured components (pawl and ramp) that can be produced with standard machining processes. These components are designed to be robust and maintenance-free, effectively serving as a simple, reliable solution that does not require complex control systems or expensive materials.
3Reliability
If the handle is constrained by a lever mechanism linked to the frame, then the handle can be blocked during circular translation, but the mechanism cannot be used because the door shifts outwards and is no longer aligned with the fuselage
Solution Approach 1:
The locking mechanism is designed to be dynamically active only when needed. The pawl is free to move during the escape phase, allowing the handle to rotate freely, and becomes constrained only when the handle reaches its end position and the ramp contacts the pawl during circular translation. This dynamic behavior adapts to the door's movement phases without requiring a complex, always-active constraint system.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
An aircraft door (1) with lateral escape of the stops and opening by circular translation being provided with a pivoting manoeuvring arm (2) coupled to a forearm (3) articulated on the door and a mechanism for locking at least one actuation handle (4), characterized in that it comprises at least one pin (41, 42) carried by the handle (4) and at least one ramp (21, 22) of circular profile, the pin and the ramp being relatively positioned such that, in the end-of-travel position of the handle (4) corresponding to the end of the escape of the stops and during the circular translation of the door as far as its complete opening, the rotation of the handle is blocked by contact of the pin (41, 42) against the ramp (21, 22).