Hidden Drag Link Assembly for Low-Noise Thrust Reversers

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Solution Overview

Problem

Existing thrust reverser assemblies in aircraft nacelles suffer from increased drag and noise due to the presence of drag links and blocker doors in the bypass flow duct, which disrupt the smoothness of the flow path surfaces.

Innovation Solution

The design incorporates a hidden drag link mechanism where the drag link is located along the first surface of the blocker door in the stowed state, with a guide arm and guide roller system that guides the blocker door's translation, allowing the drag link to deploy radially inward during thrust reversal, minimizing obstruction in the bypass flow duct.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If drag links and blocker doors are present in the bypass flow duct, then the thrust reverser mechanism can function, but the smoothness of flow path surfaces deteriorates, increasing drag and noise

Engineering Contradiction:
Improvethrust reverser mechanism functionalityVSAvoiddrag and noise
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The drag link is extracted from the traditional location within the bypass flow duct and repositioned to connect the blocker door to the inner fixed structure. This extraction removes the drag link from the airflow path, eliminating its harmful effect on flow smoothness while preserving its mechanical function of controlling the blocker door during thrust reversal.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The drag link is repositioned in a different spatial dimension - connecting to the inner fixed structure rather than being positioned within the bypass flow duct. This dimensional change allows the drag link to perform its mechanical function without interfering with the airflow in the bypass duct, thereby reducing drag and noise.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If the drag link is repositioned to the inner fixed structure, then drag and noise are reduced, but the complexity of the mechanism increases

Engineering Contradiction:
Improvedrag and noiseVSAvoidmechanism complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The inner fixed structure serves multiple functions: it provides the mounting point for the drag link, supports the blocker door mechanism, and maintains the structural integrity of the thrust reverser assembly. By making the inner fixed structure multi-functional, the patent avoids adding separate components, thereby limiting the increase in mechanism complexity.

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

Solution Approach 2:

The drag link connection to the inner fixed structure merges the drag link function with the existing structural support system. Instead of creating a separate mounting mechanism, the patent integrates the drag link connection into the inner fixed structure, combining multiple functions into a single integrated component.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4116567B1Hidden drag link for thrust reverser assembly
Publication Date: 2025.09.24 ROHR INC
  • EP4116567B1 patent drawingFigure 1A~1B
  • EP4116567B1 patent drawingFigure 2A
  • EP4116567B1 patent drawingFigure 2B

AI summary

A thrust reverser assembly (16) may comprise a cascade of vanes (114) and a sleeve (112) configured to translate relative to the cascade of vanes (114). The sleeve (112) may include an inner sleeve portion (120), an outer sleeve portion (122), and a pressure sleeve portion. The pressure sleeve portion may be located radially inward of the outer sleeve portion (122) and may extend forward from the inner sleeve portion (120). A blocker door may be hingedly coupled to the pressure sleeve portion. A drag link (154) may be pivotably coupled to the blocker door (150). A forward end of the drag link (154) may be configured to deploy radially inward in response to aft translation of the sleeve (112).