Locking Mechanism Using Rotatable Flaps for Aircraft Actuators

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Solution Overview

Problem

Conventional locking/unlocking mechanisms for deployable systems, such as ram air turbine actuators, require large solenoids and complex linkages, which are heavy, costly, prone to wear, and vulnerable to vibrations, making them unsuitable for lightweight and reliable applications in aircraft.

Innovation Solution

A mechanism using rotatable flaps biased by torsion springs to block axial movement, which are opened by a pull solenoid-driven action plunger to allow axial movement of the lock bolt, reducing the need for large solenoids and complex linkages, and incorporating a chamfered surface for smooth operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional linkage arrangement with solenoid is used to unlock the lock bolt, then the locking mechanism can be released, but the mechanism requires large solenoids, complex linkages, and significant axial space

Engineering Contradiction:
Improvelocking mechanism reliabilityVSAvoidlinkage arrangement complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the complex linkage arrangement from the conventional unlocking mechanism. Instead of using links and joints to transmit force from the solenoid to the lock bolt, the invention directly couples the solenoid-driven plunger to the lock bolt, removing unnecessary intermediate components and simplifying the overall mechanism while maintaining reliable locking and unlocking functionality

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent inverts the conventional approach by having the solenoid plunger directly engage and move the lock bolt axially, rather than using the solenoid to move linkages that indirectly affect the lock bolt. This inversion eliminates the need for complex transmission mechanisms and reduces the overall device complexity while preserving the essential locking function

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If a conventional linkage arrangement with multiple joints is used, then the locking mechanism can be actuated, but the joints are prone to wear and damage

Engineering Contradiction:
Improvelocking mechanism reliabilityVSAvoidcomponent service life
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent removes the linkage arrangement with multiple joints from the system, eliminating the sources of wear and damage. The direct coupling between the solenoid plunger and lock bolt ensures there are no intermediate joints to wear, thereby extending the service life of the locking mechanism while maintaining its reliability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

By inverting the conventional approach and directly engaging the solenoid plunger with the lock bolt, the patent eliminates the jointed linkage structure that would otherwise be subject to wear and damage over time, thereby improving the duration of action and service life of the moving components

Inventive Principle:
Principle #13The other way round (Inversion)

3Reliability

If a conventional linkage arrangement is used, then the locking mechanism can function, but the mechanism is vulnerable to vibrations

Engineering Contradiction:
Improvelocking mechanism reliabilityVSAvoidvibration susceptibility
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and removes the linkage arrangement that would be vulnerable to vibrations from the conventional mechanism. The direct coupling between the solenoid plunger and lock bolt eliminates intermediate joints and links that could be affected by vibrations, thereby improving the reliability of the locking mechanism in vibration-prone environments

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

By inverting the conventional approach and using direct engagement rather than a linkage arrangement, the patent eliminates the components that would be susceptible to vibration-induced failures, thereby enhancing the locking mechanism's resistance to vibrations while maintaining its functional reliability

Inventive Principle:
Principle #13The other way round (Inversion)

4Reliability

If large solenoids are used to displace the lock bolt against spring force, then the locking mechanism can be unlocked, but the solenoid size and weight increase

Engineering Contradiction:
Improveunlocking mechanism reliabilityVSAvoidsolenoid weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent removes the requirement for large solenoids by eliminating the linkage arrangement that would otherwise require significant force to actuate. The direct coupling allows a smaller, lighter solenoid to effectively move the lock bolt since there are no intermediate linkages to overcome, thereby reducing the weight of the moving object while maintaining reliable unlocking functionality

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

By inverting the conventional approach and directly engaging the solenoid plunger with the lock bolt, the patent eliminates the mechanical disadvantage of linkage arrangements, allowing a smaller, lighter solenoid to achieve the same unlocking effect, thereby reducing the weight of the moving object while preserving reliability

Inventive Principle:
Principle #13The other way round (Inversion)

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 reduces the number of components, manufacturing costs, and susceptibility to vibrations, resulting in a more reliable, smaller, and secure locking/unlocking system that can easily adapt to existing actuators, while minimizing the forces required for actuation and enhancing impact absorption.

Implementation Method 1

A mechanism using rotatable flaps biased by torsion springs to block axial movement

Methodology Applied
Scientific EffectTorsion spring: Torsion Spring

Implementation Method 2

which are opened by a pull solenoid-driven action plunger

Methodology Applied
Scientific EffectSolenoid: Solenoid

Data Source

PatentEP3284677B1Locking and unlocking mechanism
Publication Date: 2020.04.22 HAMILTON SUNDSTRAND CORP
  • EP3284677B1 patent drawingFigure 1
  • EP3284677B1 patent drawingFigure 2A
  • EP3284677B1 patent drawingFigure 2B

AI summary

A locking mechanism for releasably locking a lock bolt against axial movement, the mechanism comprising: a locking mechanism for releasably locking a lock bolt against axial movement, the mechanism comprising: an elongate member 1 axially moveable relative to a housing and, in use, in moveable engagement with a lock bolt; a flap assembly 2 moveable between a first, closed position, located between the elongate member and the housing so as to prevent axial movement of the elongate member towards the housing, and a second, open position allowing the elongate member to move axially towards the housing.