Actuator Lock Mechanism With Cam-Guided Pin Anti-Stick Path
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Solution Overview
Problem
Conventional actuator mechanisms for aircraft engine cowls can become stuck in intermediate positions during transition from locked to stowed states, leading to false locking and potential damage due to reliance on spring biased detent balls, which limits angular deviation tolerance and is sensitive to environmental factors.
Innovation Solution
The actuator system incorporates a sloping engagement surface and resilient detent mechanism within the lock mechanism, allowing the locking pin to follow a ramp and ensuring proper engagement without relying on spring biased detent balls, thus preventing intermediate position sticking and enhancing angular deviation tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spring biased detent ball mechanism is used to prevent intermediate position sticking, then the actuator can avoid false locking, but the system becomes sensitive to environmental factors and limited in angular deviation tolerance
Solution Approach 1:
The patent removes the spring biased detent ball mechanism from the system and replaces it with a cam profile based locking mechanism. The cam profile is designed to guide the locking pin through a controlled path that ensures proper engagement while accommodating angular deviations without requiring spring biased detent balls.
Solution Approach 2:
The patent employs a cam profile with specific curved geometry that guides the locking pin through a predetermined path. The cam profile's shape ensures that the pin follows the desired trajectory during actuator extension and retraction, providing reliable locking while accommodating angular deviations through the inherent geometry of the cam surface.
2Reliability
If the actuator is not fully extended before retraction, then the actuator may stop in an intermediate position causing false locking, but requiring full extension increases operational time and complexity
Solution Approach 1:
The cam profile is designed to create a self-correcting mechanism where the geometry of the cam surface automatically guides the locking pin into the proper engagement position as the actuator extends. This preliminary geometric constraint ensures that even if the actuator is not fully extended, the pin will follow the cam profile into correct alignment, preventing false locking without requiring additional time for full extension.
3Reliability
If spring biased detent balls are used to ensure proper locking engagement, then locking reliability improves, but the mechanism becomes more complex and sensitive to viscosity and temperature variations
Solution Approach 1:
The patent replaces the spring biased detent ball mechanism with a cam profile based system. Instead of using spring force and ball-detent engagement, the locking function is achieved through the geometric profile of the cam surface that guides the pin into proper engagement, eliminating the need for springs, balls, and associated adjustment mechanisms.
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 prevents the actuator from becoming stuck in intermediate positions, ensuring reliable locking and unlocking operations across varying angular alignments and environmental conditions, reducing the risk of damage and false locking indications.
Implementation Method 1
a resilient detent in the paths for a locking pin provided by the lock mechanism such that once the locking pin has moved beyond a predetermined position in the extending direction the resilient detent prevents return movement of the pin along the entry path
Implementation Method 2
A spring biased detent ball retainer (described further below) ensures that before the actuator locks onto such an intermediate point, the detent ball which is timed to run over a cam-like profile, rotates the collar lock so that the lock pin either moves into the locked state or the unlocked state
Data Source
Figure 1
Figure 2~3
Figure 4A~4B
AI summary
An actuator system comprising a rotatable lock mechanism defining a path for an actuator pin as the actuator is expanded and retracted, wherein the lock mechanism defines an entry passage through which the pin enters as the actuator extends, a guide surface along which the pin travels from the entry passage as the actuator retracts, a locking recess into which the pin is guided by the guide surface, and an exit passage into which the pin is guided as it is caused to leave the lock recess by extension of the actuator and subsequent retraction; whereby a detent surface is provided to prevent the pin returning back into the lock recess when the actuator is extended to cause the pin to leave the lock recess; and whereby the lock mechanism provides a sloping engagement surface for the pin, either side of the entry passage.