Actuator Gravity Deployment Locking Mechanism

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Electrically powered actuators for aircraft landing gear face difficulties in allowing movement to the deployed position under gravity in case of failure and locking the gear in place, making it hard to reset the actuator to its stowed position.

Innovation Solution

An actuator design featuring a screw shaft, nut, tine component with projections, and a lock member that automatically locks the nut in the extended position using a resilient bias and solenoid actuator, along with a releasable restrictor arrangement to facilitate axial movement under gravity and automated resetting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If an electrically powered actuator is used to drive landing gear, then power consumption is reduced and control precision is improved, but the ability to allow gravity-driven deployment and locking in case of failure is compromised

Engineering Contradiction:

Improvepower consumptionVSAvoidfailure mode handling

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The actuator system is segmented into multiple independent components: the motor-driven screw shaft for normal operation, and the separate gravity-driven locking mechanism with tine fingers and lock member for failure mode handling. This segmentation allows each component to perform its specialized function independently, resolving the contradiction between energy efficiency and failure mode reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The locking mechanism is designed to be self-activating under gravity force when the actuator fails. The tine fingers automatically deflect and engage with the lock member without requiring external power or control signals, enabling the system to service itself in failure conditions while maintaining low power consumption during normal operation.

Inventive Principle:

Principle #25Self-service

2Reliability

If a locking mechanism is added to secure the nut in extended position, then safety is improved, but device complexity increases

Engineering Contradiction:

ImprovesafetyVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The locking mechanism replaces complex electronic control systems with a purely mechanical solution. The resilient tine fingers and lock member form a self-contained mechanical locking system that operates passively under gravity and spring force, achieving safety without adding electronic complexity to the already simple electric actuator.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The locking mechanism utilizes parameter changes in the form of elastic deformation of the tine fingers. The resilient nature of the tine fingers allows them to deflect during engagement and maintain continuous contact force, providing reliable locking through material property changes rather than complex mechanical linkages.

Inventive Principle:

Principle #35Parameter changes

3Extent of automation

If the lock member is resiliently biased towards locked position, then automatic locking is achieved, but the ability to release and reset the actuator is reduced

Engineering Contradiction:

Improveautomatic lockingVSAvoidreset capability

Core Design Contradiction:

Extent of automationVSEase of operation

Solution Approach 1:

The resilient biasing of the lock member toward the locked position creates a preliminary locking action that automatically engages when the nut reaches the extended position. This preliminary anti-action ensures locking occurs automatically without requiring control system intervention, while the inherent elasticity of the biasing mechanism allows for controlled release during resetting operations.

Inventive Principle:

Principle #9Preliminary anti-action

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

Enables the landing gear to automatically deploy and lock in the deployed position, ensuring safe landing and allowing for regular actuator testing by enabling automated resetting.

Implementation Method 1

The lock member is preferably resiliently biased, conveniently by a resilient spring, towards a locked position

Methodology Applied

Scientific EffectResilient spring bias: Spring

Implementation Method 2

the lock member preferably being moveable away from the locked position by means of an actuator, for example in the form of a solenoid actuator

Methodology Applied

Scientific EffectSolenoid actuation: Solenoid

Implementation Method 3

allowing movement of the landing gear to its deployed position under the action of gravity

Methodology Applied

Scientific EffectGravity: Gravitation

Data Source

PatentUS8191440B2Actuator

Publication Date: 2012.06.05 GOODRICH ACTUATION SYST

AI summary

An actuator comprises a screw shaft, a nut translatable along the shaft between a retracted position and an extended position, a tine component carried by the nut, the tine component including tine fingers formed with projections each being engageable with a formation provided on a housing when the nut occupies its extended position to secure the nut against axial movement, and a lock member engageable with the tine fingers to restrict radial movement of the tine fingers.