Aircraft Slat Brake Control for Unrestrained Motion Arrest

Solution Overview

Problem

Existing slat actuation designs for aircraft are bulky, costly, and complex, often incorporating dual rotary actuators with passive brakes, which can lead to unrestrained slat conditions.

Innovation Solution

A system featuring a brake mechanism that engages with a flight control surface, such as a slat, to arrest unrestrained motion without additional actuators, using a linear hydraulic actuator and sensors to detect disengagement, and a control unit to activate the brake via hydraulic fluid and pistons.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dual rotary actuators with passive brakes are used, then unrestrained slat conditions are prevented, but the system becomes bulky, costly, and complex

Engineering Contradiction:

Improveprevention of unrestrained slat conditionsVSAvoidcomplexity of actuation system

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the brake function from a separate dual actuator system and integrates it into the existing actuator design. The brake mechanism is incorporated as an internal component within the rotary actuator, eliminating the need for dual actuators while maintaining the ability to prevent unrestrained slat motion

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The brake mechanism is merged with the actuator housing and internal components. The stationary brake shoe and movable brake shoe are positioned within the actuator assembly to engage with the gear, combining multiple functions (actuation and braking) into a single integrated unit

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If dual rotary actuators with passive brakes are used, then unrestrained slat conditions are prevented, but the system weight increases

Engineering Contradiction:

Improveprevention of unrestrained slat conditionsVSAvoidweight of actuation system

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The brake mechanism is merged with the actuator housing and internal components. The stationary brake shoe and movable brake shoe are positioned within the actuator assembly to engage with the gear, combining multiple functions (actuation and braking) into a single integrated unit

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The brake system utilizes the existing actuator components (housing, gear, shaft) as part of its structure. The stationary brake shoe is attached to the actuator housing, and the movable brake shoe is connected to the actuator shaft, allowing the actuator to serve both actuation and braking functions without requiring entirely separate components

Inventive Principle:

Principle #25Self-service

3Reliability

If dual rotary actuators with passive brakes are used, then unrestrained slat conditions are prevented, but the system cost increases

Engineering Contradiction:

Improveprevention of unrestrained slat conditionsVSAvoidmanufacturing cost of actuation system

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts the brake function from a separate dual actuator system and integrates it into the existing actuator design. The brake mechanism is incorporated as an internal component within the rotary actuator, eliminating the need for dual actuators while maintaining the ability to prevent unrestrained slat motion

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The brake mechanism is merged with the actuator housing and internal components. The stationary brake shoe and movable brake shoe are positioned within the actuator assembly to engage with the gear, combining multiple functions (actuation and braking) into a single integrated unit

Inventive Principle:

Principle #5Merging (Combining)

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

The system effectively and efficiently arrests unrestrained slat motion, reducing complexity, weight, and cost compared to prior designs, while maintaining operational reliability.

Implementation Method 1

Hydraulic fluid is configured to pass into the internal chamber and force the one or more pistons into engagement with the at least a portion of the flight control surface

Methodology Applied

Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 2

the one or more pistons are tethered to the main housing by one or more springs within the internal chamber

Methodology Applied

Scientific EffectSpring force: Spring

Data Source

PatentUS12491989B2Systems and methods for controlling a flight control surface of an aircraft

Publication Date: 2025.12.09 THE BOEING CO

AI summary

A system and a method include a flight control surface, an actuator configured to control motion of the flight control surface, and a brake configured to engage at least a portion of the flight control surface in response to the flight control surface disengaging from the actuator. The brake arrests unrestrained motion of the flight control surface when the brake engages the at least a portion of the flight control surface.