Landing-Door Safety Chain Grouping for Elevator Fault Handling

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Solution Overview

Problem

Elevator systems often take a long time to service when the landing door safety chain is accidentally unlocked or under non-active control, leading to passengers being trapped in the elevator car for extended periods due to inefficient handling of malfunctions.

Innovation Solution

A method and device that monitor the states of multiple landing door safety chains, determine a safe landing station based on the car's motion state, and strategically guide the elevator car to this station to minimize travel time and ensure passenger safety, utilizing decentralized grouping of landing door switches to enhance malfunction handling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the elevator control device stops the movement of the elevator car immediately when the landing door safety chain is disconnected, then passenger safety is improved, but the service time is extended and passengers may be trapped for a long time

Engineering Contradiction:
Improvepassenger safetyVSAvoidservice time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The landing door state detection devices are divided into multiple groups, with each group corresponding to different landing stations. This segmentation allows the system to identify which specific group has the disconnected safety chain, enabling targeted response rather than blanket stopping at any location, thus reducing overall service time while maintaining safety

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system pre-determines safe landing stations for different abnormal events based on the car's motion state. When a disconnection is detected, the control device can immediately guide the car to the pre-calculated safe landing station without performing complex real-time calculations, reducing response time while ensuring safety

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If the elevator system uses a single landing door safety chain connected in series, then the structure is simple, but the malfunction handling efficiency is low and service time is extended

Engineering Contradiction:
Improvestructure simplicityVSAvoidmalfunction handling efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The single series-connected safety chain is segmented into multiple groups corresponding to different landing stations. This allows the system to identify the specific location of the malfunction (which group is disconnected) and guide the car to the nearest safe landing station, significantly improving malfunction handling efficiency while maintaining reasonable structural complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control device acts as an intermediary that receives signals from multiple grouped safety chains, determines the car's motion state, calculates the appropriate safe landing station, and controls the car's movement. This intermediary processing enables efficient malfunction response without requiring complex hardware changes

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4620883A1Method and device for disposing of malfunction of elevator system
Publication Date: 2025.09.24 OTIS ELEVATOR CO
  • EP4620883A1 patent drawingFigure 1
  • EP4620883A1 patent drawingFigure 2
  • EP4620883A1 patent drawingFigure 3

AI summary

The present disclosure relates to elevator technology and, in particular, to a method and device for disposing of a malfunction of an elevator system, an elevator system comprising the device, and a non-transitory computer-readable storage medium storing a computer program for implementing the method. In accordance with an aspect of the present disclosure, in the provided method for disposing of the malfunction of the elevator system, states of a plurality of landing door safety chains are monitored. Subsequently, in response to an abnormal event associated with the landing door safety chains, a safe landing station at which a car is to be stopped is determined based on a motion state of the car. In the above-described method, landing door state detection devices are divided into a plurality of groups of the landing door state detection devices, and each landing door safety chain comprises one of the plurality of groups of the landing door state detection devices. In addition, the motion state of the car comprises a movement speed and a position of the car.