Dual Retention Ring Propeller Hub Redundancy
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Solution Overview
Problem
Current devices fitted with propeller blades are prone to failure due to centrifugal forces, which can cause arms to break, leading to potential device failure and the need for oversizing to ensure safety.
Innovation Solution
A dual retention ring system where two polygonal rings are mounted one on top of the other, with radial bores forming pairs to receive blade feet, allowing for redundant force absorption and operation in both resilient and plastic states, with collars for secure assembly and detection systems to monitor material state changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single retention ring is used, then the device complexity is reduced, but the reliability decreases due to potential arm breakage under centrifugal forces
Solution Approach 1:
The single retention ring is segmented into two separate rings (first retention ring and second retention ring), each capable of independently withstanding centrifugal forces. This segmentation provides redundancy so that if one ring fails, the other can still maintain the propeller blades, thereby improving reliability without requiring a single overly complex oversized structure
Solution Approach 2:
The dual ring structure acts as a pre-established safety cushion against failure. By having two independent load-bearing paths before operation begins, the system can absorb the shock of one ring failing and transition to damaged mode operation, preventing catastrophic device failure
2Strength
If the ring is oversized to prevent arm breakage, then the strength increases, but the weight of the moving object increases
Solution Approach 1:
Instead of creating a single oversized ring that would be excessively heavy, the load-bearing function is segmented across two standard-sized rings. Each ring is designed to handle the full centrifugal load independently, so neither ring needs to be oversized. This segmentation maintains required strength while avoiding the weight penalty of a single massive structure
Solution Approach 2:
The system changes the operational parameters by introducing two modes (normal and damaged). In normal mode, both rings share the load at standard stress levels. In damaged mode, one ring carries the full load but is designed to handle this temporary overload. This parameter change allows standard-sized rings to provide the strength of oversized rings without the excess weight
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 dual ring system ensures temporary operation even if one ring fails, preventing complete device failure and maintaining safety without the need for oversizing, while detection systems can initiate engine shutdown to prevent further damage.
Implementation Method 1
the materials of said first and second rings are able to pass from a resilient state to a plastic state, said device having two modes of operation: a normal mode of operation, during which said first and second rings are intact and said materials are in the resilient state; a damaged mode of operation, during which one of said first or second rings is damaged, the material of the undamaged ring being mechanically overloaded, the mechanical overload causing said material of the undamaged ring to pass into the plastic state
Implementation Method 2
detection means adapted for detecting a signal representing a change in the state of said material of at least one of said first or second rings; said signal is advantageously a vibratory signal generated by the vibrations of said device operating in the damaged state
Data Source
AI summary
A device adapted to be fitted with propeller blades includes a first retention ring including over a periphery thereof a plurality of radial bores; and a second retention ring including over a periphery thereof a plurality of radial bores, the first and second retention rings being mounted one on top of the other in the radial direction, each bore in the first retention ring being positioned opposite a bore in the second retention ring, a bore in the first retention ring arranged opposite a bore in the second retention ring forming a bore pair adapted to receive a foot of a blade.