Cam-Locking Retractable Driveshaft for Failsafe Wing Engagement
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Solution Overview
Problem
Aircraft with elongated wings occupy large spaces and often cannot fit through maintenance or repair facility doors, necessitating a mechanism to securely lock a retractable driveshaft in an engaged position without relying on an actuator for maintenance.
Innovation Solution
A cam-locking system within the engine reduction gearbox that uses a cam mechanism with a catch recess and unlocking gap, actuated by an elastic member and a shuttle, to securely engage and disengage the driveshaft with the mid-wing gearbox.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an actuator is used to maintain driveshaft engagement, then the driveshaft can be engaged and disengaged, but the system becomes unreliable as the actuator cannot be depended upon to maintain engagement
Solution Approach 1:
The cam mechanism is pre-configured with a catch recess that automatically engages with the cam surface when the driveshaft reaches the engaged position. This preliminary positioning action ensures that once engagement occurs, the mechanical geometry itself maintains the engagement without requiring continuous actuator input, thereby improving reliability while adding only a simple passive locking feature
Solution Approach 2:
The elastic member (spring) provides self-service by automatically biasing the cam mechanism into the engaged position and maintaining that position through the cam-catch geometry. The system serves itself by using the spring's stored energy to ensure positive engagement and the cam's geometric shape to maintain engagement, eliminating the need for active actuator control to sustain the engaged state
2Area of stationary object
If the wing assembly is rotated to minimize footprint, then storage space is reduced, but the driveshaft must be securely locked in engaged position during rotation
Solution Approach 1:
The cam mechanism utilizes a curved cam surface that rotates with the wing assembly. The curved geometry of the cam ensures that as the wing rotates through its full range of motion, the cam surface continuously engages with the catch recess, maintaining positive locking throughout the entire rotation arc. This curved geometric approach allows the system to accommodate the rotational movement while maintaining reliable engagement
Solution Approach 2:
The cam-locking mechanism is pre-positioned and pre-biased by the elastic member before rotation begins. This preliminary engagement ensures that the driveshaft is securely locked to the wing assembly before rotation starts, and the geometric design maintains this engagement throughout the rotation, providing reliability during the footprint-reducing maneuver
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
Ensures failsafe engagement of the driveshaft, allowing for compact storage and maintenance without additional input, maintaining the driveshaft's engagement during flight and enabling efficient stowage and retrieval.
Implementation Method 1
an elastic member and a shuttle to translate the cam between the engaged and disengaged positions
Data Source
AI summary
A cam-locking system for use with a retractable driveshaft that includes a housing, a cam carrier located at least partially in the housing, and a cam rotatably coupled to the cam carrier. Translation of the cam carrier along a central axis allows the cam to rotate into cooperative engagement with a catch recess on an interior surface of the housing, preventing the cam carrier from translating backwards, and thereby maintaining the retractable driveshaft in an engaged position. Further advancement of the cam carrier allows that cam to rotate into and unlocking gap in the interior surface of the housing, which enables the cam carrier to translate backwards along the central axis below the locked position, thereby disengaging the retractable driveshaft.