Electromechanical Actuator Locking With Hooks and Sliding Lock

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Solution Overview

Problem

Hydraulic landing gear actuation and locking systems in aircraft require additional equipment and complex high-pressure circuits, and existing electromechanical actuators lack reliable automatic locking and position sensing capabilities, especially for compliance with safety and regulatory requirements.

Innovation Solution

An internal locking device for electromechanical actuators featuring a set of movable hooks, a sliding lock, and a locking spring, which automatically engages and disengages under motor control, providing reliable locking and unlocking mechanisms, and includes position sensors for accurate locking position detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hydraulic landing gear actuation and locking systems are used, then reliable locking is achieved, but additional equipment and complex high-pressure circuits are required

Engineering Contradiction:
Improvelocking reliabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the hydraulic actuation and locking system with an electromechanical system. The motor-driven rod actuates the locking mechanism through mechanical means, eliminating the need for hydraulic pumps, high-pressure circuits, and associated control systems. The locking reliability is maintained through the motorized control and mechanical locking engagement.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention extracts and eliminates the hydraulic subsystem from the landing gear actuation and locking system. By removing the hydraulic components (pumps, valves, high-pressure circuits), the patent simplifies the overall system while retaining the essential locking function through an electromechanical alternative.

Inventive Principle:
Principle #2Taking out (Extraction)

2Device complexity

If existing electromechanical actuators are used, then equipment complexity is reduced, but reliable automatic locking and position sensing capabilities are lacking

Engineering Contradiction:
Improvesystem complexityVSAvoidautomatic locking reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The locking mechanism is designed to automatically engage and disengage based on the rod position. The movable hooks automatically lock into the cavity when the rod reaches its travel limit, and the sliding lock automatically releases them when actuated by the motor. This self-service capability eliminates the need for complex external control systems while ensuring reliable automatic locking.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent incorporates position sensors that detect the locking position of the actuator. These sensors provide feedback information about whether the landing gear is in the locked or unlocked position, enabling reliable monitoring and control of the locking state without adding significant system complexity.

Inventive Principle:
Principle #23Feedback

3Device complexity

If manual locking mechanisms are used, then device complexity is minimized, but reliable 'gear down and locked' information cannot be obtained

Engineering Contradiction:
Improvelocking mechanism complexityVSAvoidlocking position information
Core Design Contradiction:
Device complexityVSLoss of information

Solution Approach 1:

The patent uses position sensors to detect and indicate the locking position of the actuator. While not literally using color changes, the sensors provide visual or electrical signals that indicate whether the gear is locked or unlocked, eliminating the loss of locking position information while keeping the mechanism relatively simple.

Inventive Principle:
Principle #32Color changes

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 automatic and reliable locking of the actuator in both extended and retracted positions, reducing the need for additional equipment and ensuring compliance with safety and regulatory standards by providing secure 'gear down and locked' information.

Implementation Method 1

a locking spring interposed between the lock and a stop linked to the cylinder

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

A solenoid actuator is actuated to move the locking member to the released position

Methodology Applied
Scientific EffectSolenoid: Solenoid

Data Source

PatentEP3645914B1Locking device for electromechanical actuator and electromechanical actuator comprising this device
Publication Date: 2023.10.25 SAFRAN ELECTRONICS & DEFENSE ACTUATION
  • EP3645914B1 patent drawingFigure 1
  • EP3645914B1 patent drawingFigure 2~5

AI summary

This locking device for an electromechanical actuator comprises a rod (3) that is movable relative to a cylinder (2) under the action of a motor actuating the rod, an assembly of at least one hook (10) that can be moved between a locked position in which said hooks (10) engage in an indentation (15) and an unlocked position in which said set of hooks (10) is released from the indentation (15), one of said set of hooks and the indentation being provided on the cylinder and the other on the rod (3). It comprises a sliding lock (19) that can slide relative to said hooks and to the indentation between a holding position in which said hooks (10) are held in the locked position and a released position in which said hooks are released under the action of the motor actuating the rod (3).