Tapered Yoke Rod Locking System for Nacelle Cowl

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Solution Overview

Problem

The current structural mounting configuration of nacelles with pivoting cowls attached around a perpendicular axis to the longitudinal axis of the nacelle disrupts the structural connection between the cowls and the pylon, preventing the use of previous structural links and causing issues with aerodynamic continuity and accessibility during maintenance.

Innovation Solution

A removable locking system with a tapered yoke and rod assembly that self-centers, allowing for structural connection and disengagement, featuring remote mechanical control and position sensors for precise locking and unlocking, and optionally a floating connection to accommodate thermal expansion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the cowl is attached to the pylon with a fixed structural connection, then the structural strength and aerodynamic continuity are improved, but the ease of operation for opening and closing the cowl deteriorates

Engineering Contradiction:
Improvestructural connection strengthVSAvoidcowl opening and closing operation
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The locking system transitions from a fixed structural connection to a dynamic system that can switch between locked and unlocked states. The rod moves between a retracted position (allowing cowl opening) and an engaged position (providing structural connection), enabling the system to adapt its characteristics based on operational requirements.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The locking system is divided into separate functional components: the yoke attached to the pylon, the rod mounted on the cowl, and the engagement mechanism. This segmentation allows independent movement and function of each component, enabling both secure locking and easy operation.

Inventive Principle:
Principle #1Segmentation

2Ease of repair

If the cowl is opened for maintenance access, then the ease of repair is improved, but the aerodynamic continuity and structural integrity deteriorate

Engineering Contradiction:
Improveengine accessibilityVSAvoidaerodynamic continuity
Core Design Contradiction:
Ease of repairVSStability of the object's composition

Solution Approach 1:

The locking system provides dynamic control over the cowl state, allowing it to be securely closed during flight operations to maintain aerodynamic continuity, and easily opened during maintenance when accessibility is required. The system adapts to different operational phases.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The tapered entry geometry provides self-centering functionality, automatically aligning the rod with the yoke during engagement without requiring precise manual alignment, thereby simplifying the maintenance operation while ensuring proper aerodynamic sealing when closed.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If a removable locking system is used to allow easy opening, then the ease of operation is improved, but the reliability of the structural connection deteriorates

Engineering Contradiction:
Improvecowl accessibilityVSAvoidlocking connection reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The tapered entry geometry creates a conical engagement surface that provides self-centering and automatic alignment. This curved geometry ensures reliable engagement by guiding the rod into proper position within the yoke, compensating for any misalignment and ensuring consistent locking reliability.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The engagement mechanism provides mechanical feedback through the engagement of the rod with the yoke, ensuring that the locked position is clearly established. The self-centering action provides inherent feedback that confirms proper alignment and engagement, enhancing reliability.

Inventive Principle:
Principle #23Feedback

4Manufacturing precision

If the locking system uses precise alignment features, then the manufacturing precision is improved, but the device complexity increases

Engineering Contradiction:
Improvealignment precisionVSAvoidlocking system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The tapered entry geometry provides self-centering functionality, automatically aligning the rod with the yoke during engagement without requiring precise manual alignment or complex alignment mechanisms. The geometry itself performs the alignment function, reducing overall system complexity while maintaining high precision.

Inventive Principle:
Principle #25Self-service

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

Ensures secure structural connection between the pylon and movable cowls while allowing for easy opening, maintaining aerodynamic continuity and facilitating maintenance by providing a reliable locking mechanism that adapts to thermal expansion and alignment issues.

Implementation Method 1

the yoke has a tapered entry. Such an entry allows self-centering of the yoke with the rod when the latter is brought into the locking position

Methodology Applied
Scientific EffectSelf-centering: Geometry

Data Source

PatentEP2057071B1Locking system for a movable nacelle cowl
Publication Date: 2011.11.02 AIRCELLE SA
  • EP2057071B1 patent drawingFigure 1
  • EP2057071B1 patent drawingFigure 2~3
  • EP2057071B1 patent drawingFigure 4~5

AI summary

The present invention relates to a locking system (20) for a movable lateral cowl (8) of a turbine engine nacelle intended to be connected to a pylon (4) of an aircraft, comprising, on the one hand, a clevis (21) intended to be connected to the pylon, and, on the other hand, a rod (22) intended to be mounted on the movable cowl and capable of engaging with the clevis when the movable cowl is in the closed position, characterized in that the rod is mounted so that it can move translationally along a substantially longitudinal axis of the movable cowl so as to form a slider which can shift between a locked position, in which it is engaged with the clevis and provides a structural connection between the pylon and the movable cowl, and an unlocked position, in which it is disengaged from the clevis and allows the movable cowl to be opened.