Propeller Safety Device with Retractable Blade for Crash Impact

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Solution Overview

Problem

Air mobility vehicles lack a safety measure to prevent secondary accidents caused by propeller fragments scattering during crashes, as the propeller hits the ground and breaks, leading to potential hazards.

Innovation Solution

A propeller safety device with a shaft, fixed part, and moving part that can be inserted into the fixed part upon detecting a crash, using a driving module to reduce the propeller's length and prevent it from hitting the ground, featuring a piston portion, launch portion, and elastic portion to facilitate rapid insertion and secure the moving part within the sliding space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the propeller maintains its full length during flight, then propulsion efficiency is improved, but during crash the propeller hits the ground and breaks causing fragments to scatter

Engineering Contradiction:

Improvepropulsion efficiencyVSAvoidpropeller fragment scattering

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The propeller blade is designed with a movable portion that can dynamically change its position between extended (for propulsion) and retracted (for crash safety) states. The movable part is guided by guide slits and support portions to slide into the hollow portion of the fixed part, transforming the static propeller structure into a dynamic one that adapts to different operational conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The propeller blade is segmented into a fixed part and a movable part that can be separated spatially. The movable part is disposed in a hollow portion of the fixed part when retracted, and can extend outward when needed for propulsion. This segmentation allows the propeller to have both extended length for efficiency and compact form for safety.

Inventive Principle:

Principle #1Segmentation

2Reliability

If a safety device is added to the propeller, then crash safety is improved, but device complexity increases

Engineering Contradiction:

Improvecrash safetyVSAvoidpropeller structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The safety function is merged with the propeller blade structure itself rather than being a separate add-on device. The movable part that forms part of the blade also serves as the component that retracts for safety, and the guide slits and support portions are integrated into the blade's internal structure. This merging reduces overall system complexity compared to adding an independent safety mechanism.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The propeller blade's own structure provides the safety function through its movable part that can retract into the fixed part. The guide slits and support portions within the blade itself guide and constrain the movable part, allowing the blade to serve its own safety needs without requiring external safety devices.

Inventive Principle:

Principle #25Self-service

3Speed

If the moving part is rapidly inserted into the sliding space during crash, then fragment scattering is prevented, but the driving module complexity increases

Engineering Contradiction:

Improveinsertion speedVSAvoiddriving module

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The elastic portion is pre-loaded or positioned to provide immediate restoring force when the crash occurs. The elastic portion connects the movable part to the fixed part and automatically exerts force to push the movable part into the sliding space upon crash detection, providing rapid response without requiring complex active driving mechanisms.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The complex mechanical driving system is replaced or supplemented with an elastic mechanical system. The elastic portion provides the necessary force for rapid insertion through elastic deformation and recovery, substituting for more complex motorized or pneumatic driving mechanisms while achieving the required insertion speed.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 device effectively reduces the risk of secondary accidents by ensuring the propeller does not break upon impact, minimizing the scattering of fragments and enhancing safety during air mobility crashes.

Implementation Method 1

an elastic portion provided between the first end of the moving portion and the fixed portion and configured to be transformable elastically

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

a launch portion provided at the fixed portion, and configured to generate explosive force when the signal indicative of the crash of an air mobility is input

Methodology Applied

Scientific EffectExplosion: Explosion

Data Source

PatentUS11866150B2Propeller safety device

Publication Date: 2024.01.09 HYUNDAI MOTOR CO LTD

AI summary

A propeller safety device is provided. The propeller safety device is configured to insert a moving part of a propeller into a fixed part during a crash of an air mobility to allow a reduction in the total length of the propeller, thereby preventing the propeller from hitting the ground. Accordingly, a secondary accident due to fragments formed when the rotating propeller hits the ground is prevented.