Elevator Safety Actuator Reset During Upward Car Motion

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Solution Overview

Problem

Existing elevator systems require manual intervention and multiple attempts to reset electronic safety actuators (ESAs) due to alignment issues caused by elevator car bounce or swing, especially near the top of the hoistway, leading to inefficiency and passenger distress.

Innovation Solution

A method and system where the elevator car is moved upwards during the reset operation to align and operate an electromagnet, pulling the magnetic actuator pad laterally away from the guide rail, avoiding bounce or swing, and ensuring reliable ESA reset without stopping the car.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the elevator car is stopped to align the electromagnet with the magnetic actuator pad for reset operation, then alignment precision can be improved, but bounce or swing of the elevator car prevents reliable alignment

Engineering Contradiction:
Improvealignment precisionVSAvoidreset reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies the Dynamics principle by performing the reset operation during continuous upward movement of the elevator car rather than stopping. The electromagnet is activated while the car is moving, and the magnetic actuator pad is pulled into alignment and held in the reset position dynamically during the upward motion, eliminating bounce and swing interference.

Inventive Principle:
Principle #15Dynamics

2Reliability

If multiple attempts are made to reset the safety actuator, then alignment can eventually be achieved, but time is lost and passenger distress increases

Engineering Contradiction:
Improvereset successVSAvoidreset time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies the Preliminary action principle by pre-positioning the electromagnet and magnetic actuator pad such that they will be in alignment during the upward movement of the elevator car. The reset operation is triggered automatically when the alignment condition is met during upward motion, eliminating the need for multiple manual adjustment attempts.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If the elevator car is moved upwards to align components for reset, then alignment can be achieved, but the car must be stopped and positioned precisely which is difficult near the top of the hoistway

Engineering Contradiction:
Improvecomponent alignmentVSAvoidcar positioning
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent eliminates the need for precise static positioning by performing the alignment and reset operation dynamically during upward movement. The electromagnet and magnetic actuator pad are designed to align automatically at a specific point during the upward travel, and the reset is executed while the car is in motion, avoiding the operational difficulties of precise positioning near the top of the hoistway.

Inventive Principle:
Principle #15Dynamics

4Reliability

If the magnetic actuator pad is pulled laterally away from the guide rail while the elevator car is moving upwards, then reset reliability is improved by avoiding bounce, but the electromagnet must be operated during motion which adds operational complexity

Engineering Contradiction:
Improvereset reliabilityVSAvoidoperational complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies the Self-service principle by designing the system so that the upward movement of the elevator car itself provides the necessary conditions for successful reset. The motion of the car brings the electromagnet and magnetic actuator pad into alignment, and the continuous upward movement prevents bounce, allowing the reset to be executed using the system's own operational motion rather than requiring separate positioning mechanisms.

Inventive Principle:
Principle #25Self-service

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 efficient and reliable resetting of safety actuators by maintaining elevator motion, reducing alignment difficulties and passenger distress, and allowing quicker evacuation after reset.

Implementation Method 1

the safety actuator comprises an electromagnet operable to pull the magnetic actuator pad laterally away from the guide rail when the electromagnet is aligned with the magnetic actuator pad during a reset operation

Methodology Applied
Scientific EffectElectromagnetic attraction: Electromagnet

Data Source

PatentEP4289776B1Resetting a safety actuator in an elevator system
Publication Date: 2026.01.28 OTIS ELEVATOR CO
  • EP4289776B1 patent drawingFigure 1
  • EP4289776B1 patent drawingFigure 2
  • EP4289776B1 patent drawingFigure 3A~3B

AI summary

In a method of resetting a safety actuator (52) in an elevator system, an elevator controller receives a signal to reset the safety actuator (52) and moves the elevator car upwards relative to the guide rail (106a) so as to release the safety brake (48). A safety board controller is instructed to operate an electromagnet (62) in the safety actuator (52) to pull a magnetic actuator pad (54') laterally away from the guide rail (106a) to a reset position while the elevator car is moving upwards during the reset operation.