Pivot Door Thrust Reverser Locking Mechanism

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Solution Overview

Problem

Current pivot door thrust reversers for turbofan gas turbine engines lack an effective locking mechanism to securely manage the deployment and stowage of thrust reverser doors, which is crucial for efficient thrust reversal and aircraft braking during landing.

Innovation Solution

A locking mechanism comprising a tee-handle actuator, blade assemblies, and a loose-joint coupling system that engages and disengages lock fittings on the thrust reverser doors, utilizing a spring element and proximity sensor to ensure secure locking and unlocking states, allowing for efficient deployment and stowage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a locking mechanism is added to pivot door thrust reversers, then reliability and security of thrust reverser door stowage and deployment is improved, but device complexity increases

Engineering Contradiction:

Improvesecurity of thrust reverser door stowage and deploymentVSAvoidcomplexity of locking mechanism

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The locking mechanism is divided into separate functional components: a lock fitting attached to the thrust reverser door, a blade assembly with a loose-joint coupling, and a tee-handle actuator. This segmentation allows each component to perform its specific function independently while simplifying the overall design and reducing complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The lock fitting is received within a receptacle on the thrust reverser door, creating a nested structure. The blade assembly engages with the lock fitting through this nested arrangement, providing a compact and integrated locking solution that secures the door in the stowed position without adding excessive complexity.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Strength

If a robust locking mechanism with load path is implemented, then strength and load distribution are improved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:

Improveload path for thrust reverser doorsVSAvoidmanufacturing of locking mechanism

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The loose-joint coupling automatically adjusts and self-aligns as the blade assembly engages with the lock fitting. This self-adjusting mechanism ensures proper load distribution and engagement without requiring complex alignment procedures or additional adjustment components, simplifying both manufacturing and assembly.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

Instead of using a complex active locking system that requires multiple components and adjustment mechanisms, the invention uses a passive locking approach where the blade assembly and lock fitting engage through their geometric shapes and the loose-joint coupling. This inverted approach simplifies manufacturing while maintaining strength.

Inventive Principle:

Principle #13The other way round (Inversion)

3Productivity

If minimal overstow clearance is achieved through precise locking, then productivity and efficiency are improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improveefficiency of thrust reverser operationVSAvoidclearance and alignment tolerances

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The loose-joint coupling allows for parameter changes in the engagement position as the blade assembly rotates and engages with the lock fitting. This flexibility in engagement parameters enables minimal overstow clearance to be achieved without requiring extremely tight manufacturing tolerances, as the coupling can accommodate minor variations in alignment.

Inventive Principle:

Principle #35Parameter 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

The locking mechanism provides a robust and efficient load path for thrust reverser doors, ensuring secure stowage and deployment, enhancing aircraft braking performance and operational reliability by minimizing overstow clearance and optimizing load distribution.

Implementation Method 1

A locking mechanism for a pivot door thrust reverser is disclosed herein.

Methodology Applied

Scientific EffectSpring: Spring

Implementation Method 2

utilizing a spring element and proximity sensor to ensure secure locking and unlocking states

Methodology Applied

Scientific EffectProximity sensor:

Data Source

PatentEP3517766B1Translating lock for pivot door thrust reverser

Publication Date: 2022.03.23 ROHR INC

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Figure 2A
Figure 2B

AI summary

A lock mechanism (210, 300, 400) for releasably securing a pivot door (134, 136, 202, 204) of a thrust reverser (130, 200) includes a frame (302, 402), a blade housing (312, 412) connected to the frame (302, 402), a blade member (314, 414) slidably disposed within the blade housing (312, 412) and configured to engage a lock fitting (218, 460) of the pivot door (202, 204), an actuator (212, 303, 403) configured to translate the blade member (314, 414) in a first direction (230, 306, 406) with respect to the frame (302, 402), a spring element (334, 434, 444) configured to translate the blade member (314, 414) in a second direction (232, 308, 408) with respect to the frame (302, 402), and a loose-joint coupling (322, 422) configured to connect the actuator (212, 303, 403) to the blade member (314, 414).