Magnetic Elevator Safety Brake Actuation Over Large Rail Gaps

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Solution Overview

Problem

Existing elevator systems face challenges in providing a reliable and efficient safety brake system, particularly in high-rise buildings where the risk of freefall and over-speed is higher. Current mechanical and electromechanical solutions may be complex, costly, and prone to false actuation.

Innovation Solution

A safety brake system utilizing a magnetic actuator with an array of magnetic components, including a first magnetic component and two second magnetic components, which are arranged to switch between states to move the actuator between positions. This movement is coupled through a linkage mechanism to engage or disengage the safety brake, providing a simple and reliable braking mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a mechanical governor and mechanically-actuated safety brake are used, then the safety brake can stop the elevator car, but the system becomes complex and costly

Engineering Contradiction:
Improvesafety brake reliabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the traditional mechanical governor and mechanically-actuated safety brake system with an electromagnetic actuator that uses magnetic fields to directly actuate the safety brake. This substitution eliminates complex mechanical linkages, reduceers, and mechanical sensing mechanisms while maintaining the safety function through electromagnetic force generation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts and eliminates unnecessary intermediate mechanical components from the traditional safety brake system. By using a direct electromagnetic actuation mechanism, the system removes mechanical governors, mechanical linkages, and associated complex mechanisms, keeping only the essential safety brake function with simplified actuation.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If electromagnetic actuators with mechanical linkages are used, then the safety brake can be actuated electrically, but the system remains complex and prone to false actuation

Engineering Contradiction:
Improveelectrical actuation capabilityVSAvoidlinkage mechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces electromagnetic actuators with mechanical linkages with a direct electromagnetic actuation system that uses magnetic fields to move the safety brake components. This eliminates the intermediate mechanical transmission elements while preserving electrical control capability, reducing complexity and false actuation risks.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If a simple magnetic actuator design is used, then the system is cost-effective, but it may not be able to engage the safety brake over large distances

Engineering Contradiction:
Improveactuator design simplicityVSAvoiddistance between ferromagnetic components
Core Design Contradiction:
Device complexityVSLength of stationary object

Solution Approach 1:

The patent segments the magnetic circuit into multiple ferromagnetic components (first ferromagnetic component, second ferromagnetic component, and bridge component) arranged in series. This segmentation allows the magnetic field to effectively bridge larger distances by creating multiple magnetic pathways, maintaining actuation capability while keeping the overall design simple and cost-effective.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a bridge component as an intermediary ferromagnetic element between the first and second ferromagnetic components. This intermediary component extends the magnetic flux path, enabling the actuator to engage the safety brake over larger distances while maintaining a simple and economical design.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 proposed safety brake system offers a reliable, energy-efficient, and cost-effective solution for elevator systems, capable of engaging the safety brake even over large distances between ferromagnetic components, thus enhancing safety and reducing maintenance costs.

Implementation Method 1

the magnetic field between the array and the first ferromagnetic component is reduced and the magnetic field between the array and the second ferromagnetic component is augmented so as to move the actuator from the first position to a second position

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentEP4541749A1Safety brake system
Publication Date: 2025.04.23 OTIS ELEVATOR CO
  • EP4541749A1 patent drawingFigure 1
  • EP4541749A1 patent drawingFigure 2
  • EP4541749A1 patent drawingFigure 3

AI summary

A safety brake system (40; 240) for use in a conveyance system is provided. The safety brake system (40; 240) includes a guide rail (20) and a conveyance component moveable along the guide rail (20). The safety brake system (40; 240) comprises a safety brake (42; 242), a linkage mechanism (56; 256) and an actuator (44; 144; 244) for the safety brake (42; 242). The safety brake (42; 242) is moveable between a non-braking position where the safety brake (42; 242) is not in engagement with the guide rail (20) and a braking position where the safety brake (42; 242) is engaged with the guide rail (20). The actuator (44; 144; 244) is configured to be mounted to the conveyance component and positioned between first and second ferromagnetic components. The actuator comprises an array of magnetic components comprising a first magnetic component adjacent to and arranged between two second magnetic components. The first magnetic component comprises one of a permanent magnet and an electromagnet and the second magnetic components each comprise the other of a permanent magnet and a electromagnet. When the electromagnet (66; 166; 266) of the first or second magnetic components is switched from the first state to a second state, the magnetic field between the array and the first ferromagnetic component is reduced and the magnetic field between the array and the second ferromagnetic component is augmented so as to move the actuator (44; 144; 244) from the first position to a second position against the second ferromagnetic component. The linkage mechanism (56; 256) is coupled between the safety brake (42; 242) and the actuator (44; 144; 244) such that movement of the actuator (44; 144; 244) from the first position to the second position when the electromagnet is switched from the first state to the second state causes the safety brake (42; 242) to move into the braking position. Wherein, in the second state, the electromagnet of the first or second magnetic component is energised with a first polarity and, in the first state, the electromagnet of the first or second magnetic component is energised with a second, opposite polarity.