Thrust Reverser Transcowl Locking Mechanism

Solution Overview

Problem

Existing thrust reverser systems for turbine engines lack a reliable mechanism to prevent uncommanded deployment of transcowl components, which could lead to undesirable and uncontrolled airflow redirection during aircraft landing.

Innovation Solution

A thrust reverser system that includes a transcowl, doors, a lock, and elastic elements, where the lock is configured to remain locked until the transcowl reaches an over-stow position, and the elastic elements provide a force biasing the transcowl towards the deployed position, ensuring controlled deployment and preventing uncommanded activation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a locking system is added to prevent uncommanded deployment, then reliability is improved, but device complexity increases

Engineering Contradiction:

Improveprevention of uncommanded deploymentVSAvoidlocking system structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The lock is positioned to engage with the transcowl assembly before normal deployment can occur. The locking mechanism is pre-configured to prevent movement until a specific over-stow position is reached, at which point the lock automatically disengages, allowing controlled deployment to proceed.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The locking mechanism is applied locally at the critical interface between the transcowl assembly and the engine structure. The lock engages specifically with the transcowl at the over-stow position, providing targeted prevention of uncommanded deployment without requiring a complete system-wide locking mechanism.

Inventive Principle:

Principle #3Local quality

2Reliability

If the lock remains engaged during normal operation, then safety is improved, but the transcowl cannot be deployed when needed

Engineering Contradiction:

Improveprevention of uncommanded deploymentVSAvoidcontrolled deployment

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The locking mechanism transitions from a static locked state to an unlocked state based on the dynamic position of the transcowl assembly. The lock is designed to automatically disengage when the transcowl reaches the over-stow position, enabling controlled deployment while maintaining safety during normal operation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The lock is positioned to engage with the transcowl assembly before normal deployment can occur. The locking mechanism is pre-configured to prevent movement until a specific over-stow position is reached, at which point the lock automatically disengages, allowing controlled deployment to proceed.

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If elastic elements are used to bias the transcowl toward deployed position, then deployment control is improved, but the risk of uncommanded deployment increases

Engineering Contradiction:

Improvedeployment controlVSAvoiduncommanded deployment risk

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The lock acts as a preliminary counter-action to the elastic biasing force. By preventing the transcowl from moving toward the deployed position until the over-stow position is reached, the lock counteracts the potential harmful effect of the elastic elements causing uncommanded deployment.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The lock is positioned to engage with the transcowl assembly before normal deployment can occur. The locking mechanism is pre-configured to prevent movement until a specific over-stow position is reached, at which point the lock automatically disengages, allowing controlled deployment to proceed.

Inventive Principle:

Principle #10Preliminary 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

The system effectively prevents uncommanded deployment of the transcowl, ensuring safe and controlled reverse thrust generation during aircraft landing by maintaining the lock in the locked position until the transcowl reaches the over-stow position, thereby reducing the risk of uncontrolled airflow redirection.

Implementation Method 1

a first elastic element disposed within the stowed position aperture and engaging both the support structure and the transcowl at least when the transcowl is in and between the stowed and over-stow positions. The first elastic element is configured, when engaging both the support structure and the transcowl, to supply a force to the transcowl that biases the transcowl toward the deployed position.

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS11060481B2Translating cowl thrust reverser system with over-stow unlocking capability

Publication Date: 2021.07.13 HONEYWELL INTERNATIONAL INC

AI summary

A thrust reverser system for a turbine engine includes a support structure, a transcowl, a door, a lock, and a first elastic element. The transcowl is mounted on the support structure and is translatable between a stowed position, a deployed position, and an over-stow position. The door is pivotally coupled to the support structure and is rotatable between at least a first position, a second position, and a third position. The lock is movable between a locked position, to prevent transcowl translation toward the deployed position, and an unlocked position, to allow transcowl translation toward the deployed position. The lock is only able to move to the unlocked position when the transcowl is in the over-stow position. The first elastic element is disposed within the stowed position aperture and, when engaging both the support structure and the transcowl, supplies a force to the transcowl.