Bell Crank Mechanism for Aircraft Trailing Edge Flaperon Control

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Solution Overview

Problem

Existing aircraft flight control structures face challenges in accommodating both angular and translational movements of flaperons while maintaining robustness and minimizing weight, particularly in avoiding jamming issues and weight penalties associated with cam track mechanisms.

Innovation Solution

A bell crank mechanism is used to link the movement of a hinge panel directly to a trailing edge control device, eliminating the need for cam tracks and rollers by employing a series of linked four-bar linkages that support both pivotal and translational movements, with a center link pivotally secured to the trailing edge and actuated by an input controller.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cam track mechanisms are used to support both angular and translational movements of flaperons, then robustness and movement control are improved, but weight and device complexity increase

Engineering Contradiction:
ImproverobustnessVSAvoidweight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The bell crank mechanism is divided into multiple separate links (first link, second link, third link, fourth link) connected by pivot couplings. This segmentation eliminates the need for heavy cam tracks while maintaining robustness through the distributed linkage structure, directly resolving the contradiction between reliability and weight.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mechanism transitions from a static cam track structure to a dynamic four-bar linkage system that adapts its configuration during operation. The links and pivot couplings enable both angular and translational movements through dynamic geometric relationships, reducing weight while preserving robustness.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If cam track mechanisms with rollers are used to control flaperon movement, then movement precision is improved, but manufacturing complexity and jamming issues increase

Engineering Contradiction:
Improvemovement precisionVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the cam tracks and rollers from the system, replacing them with a simplified four-bar linkage. This removal of complex components directly reduces device complexity and eliminates jamming issues while maintaining movement precision through the geometric constraints of the linkage.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The pivot couplings serve as intermediaries between the links, providing precise rotational joints without the complexity of cam-roller interfaces. These intermediaries enable smooth motion transfer and maintain manufacturing precision while simplifying the overall device structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If heavy cam tracks are used to prevent jamming and support extreme loads, then reliability is improved, but weight increases

Engineering Contradiction:
ImproverobustnessVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The static, heavy cam track structure is replaced with a dynamic four-bar linkage that achieves robustness through motion-based load distribution. The links and pivot couplings dynamically adapt to extreme loads during turbulence, maintaining reliability without requiring heavy structural components.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The mechanism uses multiple linked components working in composite fashion, where each link and pivot coupling contributes to overall structural integrity. This composite linkage system achieves the robustness of heavy cam tracks while significantly reducing weight and complexity.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3034393B1Trailing edge device with bell crank mechanism
Publication Date: 2018.10.17 THE BOEING CO
  • EP3034393B1 patent drawingFigure 1~2
  • EP3034393B1 patent drawingFigure 3
  • EP3034393B1 patent drawingFigure 4

AI summary

A bell crank mechanism 150 is configured to at least indirectly link any movement of an aircraft wing spoiler-like hinge panel to the movement of an aircraft wing 110 trailing edge flight control device 124. The aircraft wing is configured to be fixed to and to extend from an aircraft fuselage, the wing including a leading edge and a trailing edge. The flight control device is attached to the trailing edge, and any movement of the control device is directly subject to an aircraft input controller. The moveable aerodynamic hinge panel is situated proximally to the control device, and the hinge panel is separately attached to the trailing edge. As configured, the bell crank mechanism assures that any hinge panel motion is slaved to the control device in a manner intended to optimize aerodynamic performance and efficiency.