Actuator Lock Sleeve Biasing to Prevent Premature Relocking
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Solution Overview
Problem
The existing biasing systems for actuators in thrust reversers often fail to prevent the lock sleeve from returning to a locked position prematurely, leading to incorrect signaling and failure in engaging the tine lock, as the lock sleeve is sensed to be locked before the door is fully stowed.
Innovation Solution
A biasing system comprising a lock sleeve, a lock shaft, a tine with a tine finger, a biasing member, and a biasing spring, which maintains the tine finger away from the longitudinal axis during deployment and biases it against the lock sleeve upon return, preventing the lock sleeve from reaching a locked position before the lock shaft is fully returned.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lock sleeve is allowed to return freely to the locked position, then the actuator can complete its full range of motion, but the lock sleeve may return to the locked position prematurely before the door is fully stowed, causing incorrect signaling and failure to engage the tine lock
Solution Approach 1:
The biasing spring applies a preliminary counteracting force to the lock sleeve during its return movement, preventing it from reaching the locked position prematurely. This anti-action ensures the lock sleeve only returns to the locked position after the door is fully stowed, correcting the timing sequence without requiring complex control systems.
Solution Approach 2:
The biasing spring is pre-loaded to provide a predetermined biasing force that acts on the lock sleeve before it reaches the locked position. This preliminary action ensures the lock sleeve maintains proper timing relative to the door position, preventing premature engagement while allowing full range of motion.
2Measurement precision
If a biasing spring is introduced to control the lock sleeve return timing, then the timing accuracy is improved, but the device complexity increases
Solution Approach 1:
The biasing spring is integrated into the existing lock mechanism components, utilizing the lock sleeve and lock shaft as part of the biasing system. This self-service approach provides precise timing control without requiring separate control systems, sensors, or complex actuation mechanisms, thereby maintaining simplicity while improving accuracy.
Solution Approach 2:
The biasing spring functionality is merged with the existing lock sleeve and lock shaft assembly. The lock shaft serves dual purposes as both a locking component and a biasing element that interacts with the spring, eliminating the need for separate complexity-inducing components while achieving precise timing control.
3Reliability
If the tine finger is maintained away from the longitudinal axis during deployment, then the lock sleeve return timing is controlled, but the device complexity increases due to additional biasing components
Solution Approach 1:
The tine finger serves multiple functions: it acts as a locking element, a timing indicator, and a component that interacts with the biasing spring to control the lock sleeve return. This multi-functionality reduces the need for separate components, maintaining reliability while minimizing the increase in device complexity.
Solution Approach 2:
The biasing spring is nested within the existing actuator structure, utilizing the hollow or recessed spaces in the lock mechanism components. This nesting approach allows the biasing system to be integrated into the existing design without requiring additional external components, thereby controlling complexity while achieving the desired reliability.
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
This solution ensures that the lock sleeve does not return to a locked position prematurely, preventing false signaling and ensuring accurate engagement of the tine lock, resulting in a more reliable and efficient actuator system.
Implementation Method 1
a biasing spring (140) which, when the lock sleeve and lock shaft are deployed, in use, is configured to maintain a position of the tine finger away from the longitudinal axis
Data Source
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AI summary
A biasing system for an actuator is provided. The system comprises a lock sleeve (120), a lock shaft (130), a tine (100) having a tine finger (101) extending along a longitudinal axis, a biasing member (142) and a biasing spring (140). The biasing member (142) and biasing spring (140) are configured to maintain a position of the tine finger (101) away from the longitudinal axis in the direction of the lock sleeve when the lock shaft (120) and the lock sleeve (130) are deployed, in use, such that, when the lock sleeve (120) is returned, the tine finger (101) is biased against the lock sleeve (120) to prevent the lock sleeve (120) from returning to a locked position before the lock shaft (130).