Hydraulic Sync Shaft Lock for Lightweight Thrust Reverser Safety

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Solution Overview

Problem

Current thrust reverser lock designs are heavy, mechanically complex, and often require additional hydraulic control lines, making them unsuitable for newer aircraft designs and increasing the risk of accidental deployment, which can be dangerous during flight or ground maintenance.

Innovation Solution

A thrust reverser synchronization shaft lock system utilizing a rotatable shaft with radial prongs, a hydraulic lock assembly, and an electric lock assembly, which replaces traditional two-piece jaw mechanisms with a simpler rotary design, eliminating the need for dedicated hydraulic lines and reducing weight and complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional rotating jaw locking mechanisms are used, then the thrust reverser can be locked securely, but the system becomes heavy and mechanically complex

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

Solution Approach 1:

The patent replaces the traditional rotating jaw locking mechanism with a hydraulic actuation system. A hydraulic piston moves a locking jaw into engagement with a toothed rack on the synchronization shaft, eliminating complex mechanical linkages and reducing overall system complexity while maintaining secure locking capability

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

Solution Approach 2:

The invention uses hydraulic pressure to actuate the locking and unlocking of the thrust reverser synchronization shaft. Hydraulic fluid is directed to a piston that moves the locking jaw, providing a compact and reliable actuation method that reduces mechanical complexity compared to pure mechanical systems

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Device complexity

If hydraulically actuated locking elements are used, then the locking mechanism can be compact, but additional hydraulic control lines are required that are no longer provided in newer aircraft designs

Engineering Contradiction:
Improvesystem compactnessVSAvoidcompatibility with newer aircraft
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent makes the hydraulic system multi-functional by using the existing thrust reverser actuation hydraulic lines for both the primary actuation function and the secondary locking function. The same hydraulic fluid supply that moves the thrust reverser also actuates the locking jaw, eliminating the need for dedicated locking hydraulic lines and ensuring compatibility with newer aircraft designs

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention merges the locking function with the existing thrust reverser actuation hydraulic system. The hydraulic piston that actuates the locking jaw is integrated into the same hydraulic circuit used for thrust reverser movement, combining multiple functions into a single hydraulic system and eliminating additional control lines

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If rotating jaw mechanisms with multiple components are used, then the locking can be secure, but the weight of the locking system increases

Engineering Contradiction:
Improvelocking securityVSAvoidlocking system weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent extracts and eliminates unnecessary mechanical linkages from the traditional rotating jaw mechanism. By using a direct hydraulic actuation of a single locking jaw that engages with a toothed rack, the design removes intermediate mechanical components, reducing the overall weight of the locking system while maintaining secure locking capability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces heavy mechanical linkages and rotating jaw mechanisms with a lighter hydraulic actuation system. The hydraulic piston directly moves the locking jaw into engagement, eliminating the need for complex mechanical transmission components and reducing the weight of the locking system

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

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 provides a lighter, more reliable locking mechanism that prevents unintentional thrust reverser deployment, ensuring safer aircraft operations by allowing intentional movement while preventing accidental activation, without the need for additional hydraulic control lines.

Implementation Method 1

a hydraulic lock assembly that includes a housing having a tubular inner wall defining a chamber, a piston head configured to contact the tubular inner wall... urging, by a bias member, longitudinal movement of the piston rod... removing or equalizing a hydraulic stowage fluid pressure in a first fluid chamber

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 2

a bias member configured to urge the first piston rod end into engagement with the radial prong to selectably prohibit rotation of the shaft

Methodology Applied
Scientific EffectElastic force: Spring

Implementation Method 3

an electric lock assembly that includes a lock pin, and an electric actuator configured to controllably extend and retract the lock pin in and out of engagement with the lock recess

Methodology Applied
Scientific EffectElectromagnetic force: Electromagnet

Data Source

PatentEP4176169B1Hydraulic baulking sync lock
Publication Date: 2024.05.22 WOODWARD INC
  • EP4176169B1 patent drawingFigure 1~3
  • EP4176169B1 patent drawingFigure 4
  • EP4176169B1 patent drawingFigure 5A

AI summary

The subject matter of this specification can be embodied in, among other things, a thrust reverser synchronization shaft lock system includes a rotatable shaft comprising at least one radial prong extending radially from the shaft, a hydraulic lock assembly that includes a housing, a piston head having a lock recess, a piston rod extending radially away from the shaft and configured to be urged by the piston head to move the first piston rod end out of engagement with the radial prong to selectably permit rotation of the shaft, and a bias member configured to urge the first piston rod end into engagement with the radial prong, and an electric lock assembly that includes a lock pin and an electric actuator configured to controllably extend and retract the lock pin in and out of engagement with the lock recess.