Eddy Current Braking for Personal Escape Device Descent
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Solution Overview
Problem
Conventional paths of egress in buildings can become blocked during emergencies, preventing occupants from safely descending from high elevations, especially for those with physical impairments or in situations where traditional escape routes are overwhelmed.
Innovation Solution
A personal escape device featuring a rotatable shaft, magnet housing, and stator assembly with eddy current braking, allowing users to descend controlledly by unwinding a cord anchored to a secure point, utilizing magnets and conductive rings to generate a braking force for controlled descent rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional egress paths (stairwells, fire escapes) are used, then they provide standard escape routes, but they become blocked with fire or smoke or are overloaded with evacuating occupants
Solution Approach 1:
The invention divides the escape function into individual personal devices that can be used independently, rather than relying on shared collective egress paths. Each occupant has their own controlled descent device, eliminating the bottleneck effect of overloaded stairwells and fire escapes.
Solution Approach 2:
The invention transitions from horizontal/vertical movement through shared corridors and stairs to vertical descent along building exterior surfaces or interior shafts using individual devices. This creates a new dimensional escape pathway that bypasses traditional blocked routes.
2Reliability
If personal escape devices enable controlled descent from high elevations, then they provide escape capability for trapped occupants, but they require complex braking mechanisms to control descent speed
Solution Approach 1:
The invention replaces complex mechanical friction-based braking systems with an eddy current braking system that uses electromagnetic induction. Conductive rings rotate with the shaft while magnets generate eddy currents in the rings, creating electromagnetic braking force without mechanical contact, thereby reducing complexity and maintenance requirements.
Solution Approach 2:
The invention controls descent speed by adjusting parameters such as the strength and positioning of magnets relative to conductive rings, rather than using complex mechanical brake systems. This allows for smooth, adjustable speed control through electromagnetic parameter changes.
3Speed
If eddy current braking is used to control descent rate, then smooth controlled descent is achieved, but precise speed control requires multiple magnets and conductive rings with specific spacing
Solution Approach 1:
The invention varies the local properties of magnets and conductive rings at different positions around the shaft. Magnets are strategically positioned at specific angular locations with varying strengths, and conductive rings have different radial positions and thicknesses, creating localized electromagnetic interactions that collectively provide smooth speed control.
Solution Approach 2:
The conductive rings serve as intermediaries between the rotating shaft and the stationary magnets. The rings transfer rotational motion while the magnets generate eddy currents in the rings, creating a decoupled braking system that allows independent optimization of speed control and structural simplicity.
4Use of energy by moving object
If the magnet housing transmits flux density to the stator, then efficient magnetic coupling is achieved, but the magnet housing must be precisely positioned between magnets and stator
Solution Approach 1:
The magnet housing acts as an intermediary component that provides a standardized interface between magnets and the stator assembly. It includes integrated mounting features and positioning elements that ensure correct alignment during assembly, reducing the need for high-precision manual positioning while maintaining efficient magnetic flux transmission.
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
Enables safe, controlled descent of users from high elevations, accommodating various ages and abilities, with adjustable descent rates and optional hand-operated braking for precise control, enhancing emergency evacuation capabilities.
Implementation Method 1
A personal escape device features a rotatable shaft, magnet housing, and stator assembly with eddy current braking
Implementation Method 2
utilizing magnets and conductive rings to generate a braking force for controlled descent rates
Implementation Method 3
utilizing magnets and conductive rings to generate a braking force
Data Source
AI summary
A personal escape device includes a main housing, a shaft, a magnet housing, and a plurality of magnets. The shaft is rotatably coupled with the main housing and is rotatable about a rotational axis. The magnet housing is positioned in the main housing and is coupled with the shaft such that the magnet housing rotates together with the shaft. The plurality of magnets is coupled with the magnet housing such that the plurality of magnets rotates together with the magnet housing. The stator assembly is coupled with the main housing and surrounds the magnet housing. The stator assembly and the magnet housing are radially spaced from each other to define an air gap therebetween.