Frictionless Elevator Safety Actuator via Magnetic Plate Path Constraint

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Solution Overview

Problem

Existing elevator systems with electronic safety actuators face issues due to frictional wear and debris accumulation between magnets and guide rails, necessitating a reliable and convenient reset mechanism for frictionless electronic safety actuators.

Innovation Solution

A frictionless electronic safety actuator design incorporating a magnetic plate, electromagnet, linkage, biasing arrangement, and path-constraining mechanism that allows the magnetic plate to move perpendicular to the magnetic force, enabling the electromagnet to reset the safety brake without direct frictional contact with the guide rail.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a magnet is dragged against the guide rail to activate the safety brake, then the safety brake can be reliably triggered, but wear on the guide rail and debris accumulation occur

Engineering Contradiction:

Improvesafety brake triggering reliabilityVSAvoidguide rail wear and debris accumulation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical friction-based magnet dragging system with an electromagnetic field-based system. The electromagnet generates a magnetic field that acts on the magnetic plate through a non-contact path-constraining arrangement, eliminating direct mechanical contact and friction between the actuator and guide rail, thereby resolving the contradiction between reliable braking activation and guide rail wear prevention

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Object-affected harmful factors

If a spring force is used to actuate the safety brake in a frictionless manner, then guide rail wear is eliminated, but the reset mechanism becomes complex

Engineering Contradiction:

Improveguide rail wearVSAvoidreset mechanism complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical spring-based reset system with an electromagnetic system. The electromagnet can selectively generate magnetic force to move the magnetic plate in either direction (towards or away from the electromagnet), providing both actuation and reset functions through a single non-contact mechanism, thereby simplifying the overall device while eliminating guide rail wear

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The electromagnet serves multiple functions: it can attract the magnetic plate to activate the safety brake, repel the magnetic plate to reset the system, and provide controlled movement along the constrained path. This multi-functionality eliminates the need for separate spring-based actuation and reset mechanisms, reducing device complexity while maintaining frictionless operation

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of manufacture

If the magnetic plate moves directly towards the electromagnet along the magnetic force direction, then the electromagnet can be positioned simply, but the linkage cannot be effectively reset

Engineering Contradiction:

Improveelectromagnet positioningVSAvoidlinkage reset capability

Core Design Contradiction:

Ease of manufactureVSEase of operation

Solution Approach 1:

The patent introduces a path-constraining arrangement that forces the magnetic plate to move in a two-dimensional trajectory rather than directly along the magnetic force direction. The constraint path includes components in both the magnetic force direction and a perpendicular direction, enabling the magnetic plate to follow an arc or curved path that simultaneously achieves electromagnet approach and linkage reset through perpendicular displacement component

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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

This solution provides a reliable and frictionless actuation of safety brakes, reducing wear and debris interference, allowing for flexible placement and efficient reset mechanisms, and can operate with less powerful electromagnets, enhancing system reliability and maintenance efficiency.

Implementation Method 1

an electromagnet operable to selectively produce a magnetic force which acts upon the magnetic plate in a first direction towards the electromagnet and which is sufficient to overcome the biasing force to move the magnetic plate away from the first position

Methodology Applied

Scientific EffectMagnetic force: Magnetism

Implementation Method 2

a biasing arrangement arranged to apply a biasing force to the magnetic plate to bias the magnetic plate towards the first position

Methodology Applied

Scientific EffectElastic force: Spring

Data Source

PatentUS11939189B2Frictionless electronic safety actuator

Publication Date: 2024.03.26 OTIS ELEVATOR CO

AI summary

A frictionless electronic safety actuator (100; 202), for use in an elevator system, includes a magnetic plate (104); an electromagnet (102); a linkage (136); a biasing arrangement (106); and a path-constraining arrangement (112). The linkage (136) is actuatable so as to move a safety brake (204) into frictional engagement with an elevator guide rail (206). The linkage (136) is attached to the magnetic plate (104) and is moveable between a first position in which the linkage (136) is actuated and a second position in which the linkage (136) is not actuated. The biasing arrangement (106) is arranged to apply a biasing force to the magnetic plate (104) to bias the magnetic plate (104) towards the first position.