Folding Wing Latch Pin Actuation with Non-Backdriveable Roller Screw
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Solution Overview
Problem
Commercial aircraft require a folding wing system that can efficiently stow and deploy to fit within confined spaces while maximizing aerodynamic efficiency, as existing systems lack redundancy and reliability in latching mechanisms.
Innovation Solution
A folding wing system incorporating non-backdriveable mechanical latch pin actuators with redundant locks and a brake system to securely engage and disengage the folding section, utilizing a roller screw mechanism and cam locks for reliable deployment and stowage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a folding wing system is designed with multiple latch pins and redundant locks, then the reliability of the latching mechanism is improved, but the device complexity increases
Solution Approach 1:
The latching system is divided into multiple independent latch pins (typically three), each with its own actuator and locking mechanism. This segmentation allows the system to achieve high reliability through redundancy while maintaining manageable complexity by standardizing each segment's design.
Solution Approach 2:
The system incorporates redundant locks that engage before the latch pins are fully retracted, providing a safety margin. The non-backdriveable roller screw mechanism also provides inherent mechanical locking that prevents accidental disengagement, cushioning against potential failures.
2Reliability
If non-backdriveable roller screw mechanisms are used for latch pin actuators, then the security of the latched position is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent replaces simple backdriveable screw mechanisms with non-backdriveable roller screw mechanisms. This substitution provides inherent mechanical locking where the rollers engage the threaded shaft, preventing backdriving under load. The cam-actuated locking mechanism further secures the position by mechanically blocking reverse motion.
Solution Approach 2:
The roller screw mechanism incorporates localized features such as threaded sections with specific pitch directions, cam-actuated locks, and spring-loaded components. These localized quality enhancements provide the non-backdriveable characteristic only where needed, rather than complicating the entire actuator design.
3Strength
If the latch pins are oriented parallel to the hinge line, then the structural strength is improved, but the ease of operation decreases
Solution Approach 1:
The system uses actuators that dynamically control the latch pin extension and retraction timing. The pins are extended sequentially or simultaneously based on the wing's position, and the cam locks are actuated at optimal moments during the folding operation, making the process smooth and easy to operate despite the parallel orientation.
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 system ensures secure deployment of folding wings for enhanced aerodynamic efficiency, reducing fuel consumption and operating costs, while allowing for compact stowage to comply with airport space restrictions.
Implementation Method 1
a roller screw for moving the latch pin in and out of the housing, the roller screw being configured to be non-backdriveable
Implementation Method 2
a brake for the drive line
Implementation Method 3
The mechanical latch pin actuator may also include a cam lock for the latch pin
Data Source
Figure 1~2B
Figure 3
Figure 4A~4B
AI summary
A folding wing comprises a fixed section, a folding section, and a latch system for latching the folding section to the fixed section. The latch system includes a plurality of latch pins, and a corresponding plurality of non-backdriveable mechanical actuators for extending the latch pins to engage the folding section.