Aircraft Throttle Cam Coupling for Weight Reduction
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Solution Overview
Problem
The existing aeroengine throttle control devices are bulky, heavy, and require redundant components due to complex coupling systems, which increase weight and volume, and are inefficient in force transmission and lever movement.
Innovation Solution
A throttle control device with a mount and pivotally mounted code wheel and main lever, featuring first and second cam paths on the code wheel and mount, respectively, with a connecting rod and finger that allows direct movement of the code wheel by either lever while preventing movement when the other lever is away from its rest position, reducing the need for redundant components and optimizing force transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a complex coupling system including an intermediate wheel is used to connect levers to the code wheel, then the device can control both fuel flow and thrust reversal, but the device becomes bulky and heavy
Solution Approach 1:
The patent removes the intermediate wheel from the coupling system, directly connecting the levers to the code wheel through simplified cam mechanisms. This extraction of the unnecessary intermediate component reduces device weight and volume while maintaining the dual control functionality for fuel flow and thrust reversal through the remaining cam-based coupling mechanisms
Solution Approach 2:
The patent combines the control functions of both levers into a single cam-based coupling system that acts directly on the code wheel. By merging the control paths and eliminating the intermediate wheel, the design achieves weight reduction while preserving the ability to control both fuel admission and thrust reversal through the integrated cam mechanisms
2Reliability
If redundant components are added to ensure safety and reliability, then the device becomes more robust, but the weight and volume increase
Solution Approach 1:
The cam-based coupling mechanisms are designed to inherently prevent incorrect lever operation through their geometric constraints. The cam profiles automatically ensure that only one lever can be actuated at a time, providing built-in safety without requiring additional redundant components. This self-service approach maintains reliability while avoiding the weight penalty of extra safety mechanisms
3Force
If the coupling system is designed to transmit high forces, then the device is more robust, but the volume and weight increase due to larger dimensioned parts
Solution Approach 1:
The patent employs cam profiles with optimized curved surfaces to transmit lever forces to the code wheel. The cam geometry converts lever motion into rotational motion while efficiently transmitting forces through contact surfaces. This curved surface approach allows robust force transmission within a compact volume, avoiding the need for oversized mechanical components
4Ease of operation
If an intermediate wheel is used in the coupling system, then lever movement can be controlled, but the device becomes heavy and occupies more space
Solution Approach 1:
The patent removes the intermediate wheel that previously mediated lever control, replacing it with direct cam-based actuation of the code wheel. This extraction eliminates the unnecessary intermediate component while maintaining precise lever control through the cam profiles, thereby reducing device weight without sacrificing operational control
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
The solution reduces the weight and volume of the control device, enhances force transmission efficiency, and allows for smoother lever operation by enabling one lever to move while the other is near its rest position, with automatic return to rest position when the other lever is actuated.
Implementation Method 1
A first cam path is formed on a part secured to the code wheel and a second cam path is formed on the mount, the two cam paths having respective facing portions in which there is received a finger that is mounted on the main lever to slide parallel to the code wheel
Data Source
AI summary
An aeroengine control device including a mount and having pivotally mounted thereon a code wheel together with a main lever and a secondary lever, both for turning the code wheel. Each lever is movable between a rest position and a maximum actuation position. The secondary lever is mounted to pivot on the main lever. Cam paths are mounted on the code wheel and on the mount in such a manner that the main lever can move the code wheel when the main lever is moved while the secondary lever is in the rest position. The secondary lever can move the code wheel when the secondary lever is moved while the main lever is in the rest position, with movement of either lever being prevented when the other lever is clearly away from its rest position.