Folding Propeller Hinge Mechanism for Crash Fragment Containment
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Solution Overview
Problem
Air mobility vehicles face safety issues due to propeller fragmentation and scattering during crashes, leading to secondary accidents and potential damage.
Innovation Solution
A propeller apparatus with a hinge mechanism, movable bar, and driving mechanism that allows the propeller to fold upon crash detection, using elastic forces to rotate the propeller toward the fixed part, reducing the risk of fragmentation and enabling reuse after landing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the propeller is deployed for flight operation, then propulsion efficiency is improved, but safety in crash situation deteriorates due to propeller fragmentation and scattering
Solution Approach 1:
The propeller is designed with a movable blade that can dynamically change its position between deployed and folded states. The blade is connected to the hub via a hinge mechanism that allows it to rotate and fold back upon crash detection, transforming from a static rigid structure to a dynamic adaptive one that responds to crash conditions.
Solution Approach 2:
The propeller is segmented into the hub and movable blade components that can independently move relative to each other. The blade can be separated from the forward-moving trajectory by folding back, preventing the entire propeller from acting as a single fragmented hazard during crash.
2Reliability
If a folding mechanism is added to enable propeller retraction, then safety in crash situation is improved, but device complexity increases
Solution Approach 1:
The folding mechanism utilizes the crash force itself to trigger the blade folding action. The movable bar and hinge mechanism are designed so that the impact force automatically causes the blade to fold back without requiring active sensors, control systems, or powered actuators, making the safety mechanism self-activating and simple.
Solution Approach 2:
The movable bar acts as an intermediary element between the blade and hub, enabling the folding motion through a simple mechanical linkage. This intermediary component translates the crash force into the folding motion, simplifying the overall mechanism compared to direct connection designs.
3Strength
If the propeller blade is made rigid for structural strength, then manufacturing precision and strength are improved, but ability to prevent fragmentation deteriorates
Solution Approach 1:
The blade is designed with a hinge connection that allows it to dynamically change from a rigid extended position during normal operation to a folded position during crash. This dynamic capability allows the blade to maintain structural integrity while preventing harmful fragmentation by redirecting the blade away from the forward trajectory.
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
Prevents additional accidents by folding the propeller during crashes, reducing the risk of fragmentation and allowing for the propeller's reuse after the air mobility lands.
Implementation Method 1
an elastomer provided in the hinge bar to provide an elastic force to the hinge bar in a direction in which the rotation part is folded
Data Source
AI summary
A propeller apparatus of an air mobility is arranged such that a propeller is configured to fold when the air mobility crashes, thereby preventing additional accidents caused by fragments generated by the propeller hitting the ground, and enabling the propeller to be reused by unfolding the folded propeller after the air mobility lands.