Semi-Plug Door Locking Mechanism for Stable Circular Translation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing door locking mechanisms for aircraft doors during circular translation are heavy, complex, and prone to instability and damage due to uncontrolled rotation during the swivelling phase, especially when the door is not parallel to the fuselage.
Innovation Solution
A locking mechanism that combines a door handle block, a lever, and a forearm, using blocking elements and a cam system to ensure the door remains parallel to the fuselage during circular translation, preventing accidental rotation and reducing weight by eliminating unnecessary structural components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional locking mechanisms with stops and multiple connecting rods are used to maintain door parallelism during circular translation, then the door remains stable and parallel to the fuselage, but the device complexity and weight increase significantly
Solution Approach 1:
The locking mechanism is segmented into distinct functional components: a cam element with controlled movement zones, a locking element with selective engagement, and a handle element with rotational and translational phases. This segmentation allows each component to perform its specific function efficiently, reducing overall complexity while maintaining stability during circular translation.
Solution Approach 2:
The mechanism employs dynamic behavior where the cam element transitions between a first movement zone (enabling handle rotation for stop disengagement) and a second movement zone (enabling handle translation for circular translation). The locking element dynamically engages and disengages based on the operational phase, providing stability when needed and freedom of movement when required.
2Ease of operation
If mass compensation mechanisms and articulation arms are added to facilitate door handling during stop disengagement, then the ease of operation improves, but the weight of the door and aircraft increases significantly
Solution Approach 1:
The cam element acts as a counterweight mechanism during the handle rotation phase. As the handle rotates to disengage stops, the cam element's geometry provides mechanical advantage and supports the door weight, eliminating the need for additional mass compensation mechanisms while maintaining ease of operation.
Solution Approach 2:
The mechanism is designed to be self-servicing during operation. The cam element and locking element work together to automatically manage the door weight and positioning during stop disengagement and circular translation, without requiring external power sources or additional actuation systems.
3Ease of operation
If the door is allowed to rotate during the swivelling phase to accommodate non-parallel kinematics, then the ease of operation and weight reduction improve, but the risk of door instability and damage to the fuselage increases
Solution Approach 1:
The locking element engages in advance during the handle rotation phase to prepare the door for circular translation. This preliminary locking action ensures that when the handle transitions to the translation phase, the door is already secured in the correct orientation, preventing unintended rotation and ensuring stability throughout the swivelling operation.
Solution Approach 2:
The cam element serves as an intermediary between the handle operation and the door positioning. It mediates the transition from rotation to translation by controlling the locking element's engagement, ensuring that the door maintains proper orientation relative to the fuselage throughout the swivelling phase and preventing damage.
4Stability of the object's composition
If multiple guide rods are used to stabilize the door during circular translation, then the door remains parallel to the fuselage, but the device complexity and weight increase
Solution Approach 1:
The cam element performs multiple functions: it guides the handle movement, controls the locking element engagement, maintains door orientation, and enables both rotation and translation phases. This multi-functionality eliminates the need for separate guide rods, reducing weight while maintaining door parallelism during circular translation.
Data Source
AI summary
A circular translation door locking mechanism (2) assembly (2), the door being of the vehicle semi-plug type. The mechanism (2) includes a handle (3) that activates a rotation of the door (1a) on itself and two guide entities of this door (1a) in circular translation: an arm entity (4a) including an arm (4b) and a forearm (4c) rotating with respect to each other and a guide entity (5a) having a connecting rod (5b) and a lever (5c) rotating with respect to each other. The locking mechanism (2) further includes at least one device for locking the lever (5c) and forearm (4c) in relation to the door (1a) as well as a locking element of the handle (3) during the circular translation of the door (1a).