Aircraft Thrust Reverser External Cover Hinge Mechanism

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Solution Overview

Problem

The existing thrust reverser systems for aircraft propulsion units require extensive disassembly and reassembly, significantly increasing maintenance duration due to the size of half-structures and the presence of deflection grilles, which surround the engine, making it difficult to remove the engine without dismantling the entire reverser.

Innovation Solution

The thrust reverser system incorporates secondary rails and hinges that allow independent movement of external covers, enabling their rotation and translation between direct thrust and thrust reversal positions, allowing for engine removal without disassembling the entire system, along with an anti-rotation device to prevent damage and secure the secondary rails.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the entire thrust reverser is dismantled to remove the engine, then the engine can be removed, but the maintenance operation duration increases significantly

Engineering Contradiction:
Improveengine removal capabilityVSAvoidmaintenance operation duration
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The thrust reverser is divided into separable components: the reverser body and the external covers. The external covers can be detached independently from the reverser body through hinge connections, allowing engine removal without dismantling the entire reverser assembly. This segmentation enables selective disassembly of only the necessary components (external covers) to access the engine, thereby reducing maintenance time while maintaining engine removal capability.

Inventive Principle:
Principle #1Segmentation

2Productivity

If the external covers are made movable and detachable, then engine removal becomes easier and faster, but the device complexity increases

Engineering Contradiction:
Improvemaintenance operation speedVSAvoidreverser structure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The external covers are designed with hinge connections that enable dynamic movement between closed and open positions. This dynamic design allows the covers to be easily detached and reattached during maintenance operations, significantly improving productivity. The hinge mechanism provides a simple yet effective dynamic connection that balances ease of maintenance with acceptable structural complexity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The external covers are extracted as separate, detachable components from the main reverser body. This extraction allows maintenance personnel to remove only the external covers without affecting the reverser body or other components. The independent removability of external covers simplifies the maintenance process and reduces the time required for engine removal operations.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If the external hoods are opened outward for maintenance, then the engine becomes accessible, but the size of the half-structures and limited opening stroke prevent engine removal

Engineering Contradiction:
Improveengine accessibilityVSAvoidopening stroke
Core Design Contradiction:
Ease of operationVSLength of moving object

Solution Approach 1:

The external covers utilize rotational movement around a hinge axis rather than linear translation for opening. This rotational degree of freedom allows the covers to be opened fully outward, providing sufficient clearance for engine removal. The hinge mechanism transforms the limited linear opening stroke into effective rotational movement, enabling complete access to the engine while maintaining compact dimensions when closed.

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

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

This design reduces maintenance operation duration by half, enabling quicker engine removal and assembly while maintaining the reverser's mobility and preventing damage to secondary rails.

Implementation Method 1

a sliding joint allowing a translation of the external hoods between a direct thrust position and a thrust reversal position

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

hinges to which the external hoods are connected by a pivot joint allowing their rotation between the closed position and the maintenance position

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

an anti-rotation device arranged to prevent the rotation of the hinges about an axis parallel to an axis of rotation of the external hoods

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3847362B1Thrust reverser with movable structure in a c-shape for an aircraft propulsion assembly, and related maintenance method
Publication Date: 2023.11.15 SAFRAN NACELLES
  • EP3847362B1 patent drawingFigure 1~2
  • EP3847362B1 patent drawingFigure 3~4
  • EP3847362B1 patent drawingFigure 5

AI summary

Thrust reverser for an aircraft propulsion assembly, this thrust reverser comprising a movable structure provided with external covers (411) connected to hinges (51) through a pivot connection allowing the external covers (411) to rotate between a closed position and a maintenance position, said hinges (51) being connected to secondary rails (52) rigidly attached to the engine pylon (2) through a sliding connection allowing the external covers (411) to move in translation between a direct thrust position and a reverse thrust position, wherein the hinges (51) and the secondary rails (52) are independent of beams (42) to which the parts (412) of the movable structure other than the external covers (411) are connected, and a maintenance method comprising a positioning of the external covers (411) in maintenance position followed by a placement of the beams (42) and of said parts (412) of the movable structure other than the external covers (411).