Aircraft Throttle Linkage With Shearable Jam Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing throttle systems in aircraft are prone to mechanical failures due to the lack of redundancy and protection against abnormal resistance forces, which can lead to interference in the mechanical operation of the throttle linking systems, potentially causing engine control issues.
Innovation Solution
The throttle system incorporates multiple independent mechanical linking systems with designed points of failure, such as shearable fasteners and frangible links, to prevent interference and ensure continued operation even if one system fails, using Rotary Variable Differential Transformers (RVDTs) to convert mechanical rotation into electronic signals for engine control, and a voting process to determine reliable signal readings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single mechanical linking system is used to connect the throttle lever to the conversion device, then the device complexity is reduced, but the reliability decreases due to lack of redundancy against mechanical failures
Solution Approach 1:
The mechanical linking system is divided into multiple independent segments (first and second linking systems), each capable of independently transmitting rotational movement from the throttle lever to separate conversion devices. This segmentation provides redundancy so that if one segment fails, the other can still maintain engine control functionality.
Solution Approach 2:
Each mechanical linking system is designed with localized failure protection through shearable fasteners positioned at specific points. These fasteners are designed to fail locally under excessive load, isolating the failure to one linking system while preserving the integrity and functionality of the other linking system.
2Reliability
If redundant mechanical linking systems are implemented, then the reliability improves through failure protection, but the device complexity increases due to multiple independent systems
Solution Approach 1:
Both the first and second mechanical linking systems perform the same function of transmitting rotational movement from the throttle lever to conversion devices. They are universal backups of each other, allowing either system to independently fulfill the engine control requirement, thus providing redundancy without requiring fundamentally different mechanisms.
Solution Approach 2:
The shearable fasteners are extracted as separate, removable components within the mechanical linking systems. This allows for easy replacement and maintenance of individual linking systems without affecting the entire throttle control mechanism, simplifying the maintenance aspect of the redundant system.
3Reliability
If shearable fasteners are used as designed points of failure, then the reliability improves by preventing mechanical jams, but the manufacturing precision requirements increase for proper shear failure characteristics
Solution Approach 1:
The shearable fasteners are pre-installed in the mechanical linking systems with predetermined shear strengths. This preliminary action ensures that under abnormal resistance forces, the fasteners will fail at a predictable load threshold before the failure can propagate to cause mechanical jams or damage to other critical components.
Solution Approach 2:
The shearable fasteners are designed with specific material properties and geometric parameters (such as cross-sectional area and material strength) that determine their shear failure characteristics. By carefully selecting and controlling these parameters during manufacturing, the fasteners can be made to fail reliably at predetermined load levels, balancing manufacturing precision requirements with reliability benefits.
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 enhances the reliability of throttle systems by allowing continued operation even if one mechanical linking system fails, ensuring stable engine control and preventing mechanical jams, thereby improving aircraft safety and reducing the risk of engine control malfunctions.
Implementation Method 1
RVDTs, as is known in the art, take mechanical rotation, and based on angular displacement, transmit signals so that the extent of displacement can be used by digitally-based electronic systems existing in the aircraft
Data Source
AI summary
Disclosed is a throttle quadrant arrangement utilizing a single throttle lever. The single lever is independently mechanically connected to three Rotary Variable Differential Transformers (RVDTs). Failure points are engineered into the design such that when one of the mechanical jams, the mechanical connection to the other two RVDTs will not be compromised.