Dual-Input Bypass Linkage for Flight Control Actuator Failure

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Solution Overview

Problem

Redundant mechanical flight control systems in aircraft increase weight and cost while providing limited safety benefits, as they are often unnecessary due to the redundancy itself.

Innovation Solution

A dual-input mechanical bypass linkage apparatus that includes a primary link, a secondary link, and extension links coupled to actuators, allowing for a mechanical bypass when one actuator fails, eliminating the need for redundant systems by using a secondary actuator to boost or stabilize the output link.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If redundant mechanical flight control systems are implemented, then safety and reliability are improved, but weight and cost increase

Engineering Contradiction:
Improveflight control system reliabilityVSAvoidaircraft weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent merges two actuator inputs into a single mechanical linkage system where the secondary actuator can directly assist or override the primary actuator through a shared output mechanism. This integration eliminates the need for completely separate redundant systems while maintaining the ability to provide backup control authority.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The secondary actuator is designed with multi-functionality: it can operate independently as a backup, assist the primary actuator during normal operation, or override it during failures. This universal design allows a single component to serve multiple protective functions, reducing the need for additional dedicated backup components.

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

2Reliability

If redundant mechanical flight control systems are implemented, then safety and reliability are improved, but cost increases

Engineering Contradiction:
Improveflight control system reliabilityVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines backup and primary control functions into a unified mechanical linkage architecture. By sharing common linkages and output mechanisms between the primary and secondary actuators, the system reduces the total number of independent components compared to fully redundant separate systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system employs dynamic engagement and disengagement mechanisms that allow the secondary actuator to be selectively connected or disconnected from the common output. This dynamic configuration enables the system to adapt its complexity based on operational needs, using simpler configurations during normal operation and activating backup paths only when needed.

Inventive Principle:
Principle #15Dynamics

3Reliability

If redundant mechanical flight control systems are implemented, then operational continuity is improved, but the system becomes unnecessarily complex

Engineering Contradiction:
Improveoperational continuityVSAvoidmechanical linkage complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The mechanical linkage is pre-configured with bypass paths and engagement mechanisms that are ready for immediate activation in case of actuator failure. The secondary actuator's connection points and control paths are established in advance, allowing rapid switchover without requiring complex real-time reconfiguration or additional decision-making systems.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If a secondary actuator is added to provide backup control, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improveactuator failure toleranceVSAvoidlinkage system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates the secondary actuator into the existing primary actuator's mechanical linkage system rather than creating a completely separate backup system. Both actuators share common linkages and output mechanisms, reducing the overall component count compared to fully independent redundant systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The mechanical linkage system serves as an intermediary mechanism that reconciles the inputs from both primary and secondary actuators. This intermediary structure allows the secondary actuator to influence the output without requiring direct electronic or mechanical coupling to the primary actuator, simplifying the integration architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3366573B1Dual-input mechanical bypass linkage apparatus and methods
Publication Date: 2024.01.10 THE BOEING CO
  • EP3366573B1 patent drawingFigure 1
  • EP3366573B1 patent drawingFigure 2
  • EP3366573B1 patent drawingFigure 3

AI summary

Dual-input mechanical bypass linkage apparatus and methods are disclosed. An example dual-input mechanical bypass linkage apparatus includes a primary link and a secondary link spaced apart from the primary link. The dual-input mechanical bypass linkage apparatus further includes a first extension link extending between the primary link and the secondary link. The first extension link is coupled to the primary link, to the secondary link and to a first input link. The first input link is coupled to a first actuator. The primary link is coupled to a second input link. The second input link is coupled to a second actuator. The dual-input mechanical bypass linkage apparatus further includes a second extension link spaced apart from the first extension link and extending between the primary link and the secondary link. The second extension link is coupled to the primary link, to the secondary link and to an output link.