Aircraft Throttle Linkage Redundancy Against Mechanical Jams
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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 linkage systems, potentially causing engine control issues.
Innovation Solution
The throttle system incorporates three independent mechanical-rotation to electronic-conversion devices (RVDTs) connected through separate linkage systems, each with a designed point of failure that disengages upon encountering abnormal resistance, ensuring continued operation of the other systems, and a voting process to determine reliable signal readings for engine control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single mechanical linkage 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 patent divides the single mechanical linkage system into multiple independent linkage systems (first, second, and third linkage systems), each connecting the throttle lever to separate conversion devices. This segmentation ensures that if one linkage system fails, the others remain operational, thereby improving reliability while managing complexity through modular design
Solution Approach 2:
Each linkage system is designed with local fail-safe features including designed points of failure and friction-creating elements at specific locations. These localized features allow individual linkage systems to fail gracefully without affecting the entire throttle control system, improving overall reliability while maintaining manageable complexity through targeted design
2Reliability
If no designed point of failure is incorporated in the mechanical linkage system, then the strength and structural integrity are improved, but the reliability decreases due to inability to disengage upon encountering abnormal resistance forces
Solution Approach 1:
The patent incorporates designed points of failure and friction-creating elements in advance within the linkage systems. These pre-positioned weak points are strategically located to fail first when abnormal resistance is encountered, allowing the system to disengage protected components before damage propagates to critical structural elements, thereby improving reliability while preserving overall system strength
Solution Approach 2:
The designed points of failure act as protective measures in advance, absorbing abnormal forces and preventing them from reaching critical structural components. This beforehand cushioning ensures that when abnormal resistance occurs, the system fails safely at predetermined locations rather than compromising overall structural integrity
3Reliability
If the mechanical linkage systems are interconnected without independence, then the device complexity is reduced, but the reliability decreases due to interference between systems upon failure
Solution Approach 1:
The patent creates completely independent mechanical linkage systems where the first, second, and third linkage systems are mechanically separated and do not interfere with each other. Each system has its own conversion device and signal transmission path to the automated control system, ensuring that failure in one system does not propagate to others, thereby improving reliability while managing complexity through independent modular design
Solution Approach 2:
The automated control system acts as an intermediary that receives signals from multiple independent conversion devices and can selectively process signals from functional linkage systems. This intermediary capability allows the system to maintain operation using unaffected linkage systems even when others fail, improving reliability while keeping the overall architecture manageable
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 control by allowing continued operation even if one linkage system fails, ensuring stable engine control and preventing mechanical jams, thereby improving aircraft safety and reducing the risk of engine performance issues.
Implementation Method 1
The rotation of each of sticks 14 and 16 is mechanically imparted into pairs Rotary Variable Differential Transformers (RVDTs). 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 having a throttle lever which is independently mechanically connected to different Rotary Variable Differential Transformers (RVDTs). A friction lever selectively creates and releases friction from the throttle lever to enable it to be selectively positioned. The system is configured such that the mechanical connections existing between the throttle lever and the RVDTs are shielded from the friction created by the friction lever.