Elevator Stalling Detector Rescue Mode Override

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Solution Overview

Problem

Elevator systems face challenges in releasing safety gears, particularly when the elevator car is stuck due to overspeeding, as the stalling detection system can immobilize the elevator due to increasing compensation rope tension, making rescue operations difficult and unsafe, especially when the car is high in the shaft.

Innovation Solution

A method and apparatus that involves setting the stalling detector in a rescue mode to prevent false stalling indications, allowing the elevator car to be moved manually or by machinery to release safety gears, by locking or overriding the stalling detector using electromechanical or electrical means, and configuring the stalling detector to detect increased rope tension without triggering shutdowns during rescue operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the stalling detector is activated to monitor hoisting member tension, then elevator safety is improved by detecting stalling conditions, but the detector causes false alarms during rescue operations when compensation rope tension increases

Engineering Contradiction:

Improveelevator safetyVSAvoidrescue operation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The stalling detector is configured with a dynamic operational state that can be switched between normal monitoring mode and rescue operation mode. In rescue mode, the detector temporarily suspends stalling detection functionality to allow rescue personnel to manually move the elevator car without triggering false alarms, while automatically returning to normal monitoring after the rescue operation completes

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The detection threshold parameter of the stalling detector is temporarily modified during rescue operations. The system recognizes the rescue operation state and adjusts the tension threshold or detection sensitivity to prevent false stalling indications, then restores the original parameters after the rescue is complete

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If the elevator car is moved downward to release safety gears after upward gripping, then the safety gear disengagement is achieved, but the stalling detector detects increased compensation rope tension and immobilizes the elevator

Engineering Contradiction:

Improvesafety gear releaseVSAvoidelevator immobilization

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The system preliminarily sets the stalling detector to rescue operation mode before the actual rescue operation begins. This preliminary configuration prevents the detector from triggering false stalling indications when the elevator car is subsequently moved downward to release the safety gears

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control system acts as an intermediary between the stalling detector and the elevator immobilization function. It receives the tension signal from the stalling detector, determines whether the operation is a rescue operation, and selectively blocks or allows the immobilization command based on the operational context

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12252376B2Method for releasing safety gears, and a stalling detector

Publication Date: 2025.03.18 KONE OYJ

AI summary

A method for releasing safety gears of an elevator car or a counterweight of an elevator system, the elevator system including a stalling detector coupled to compensation roping associated with the elevator car and the counterweight and configured to detect an increased rope tension, includes preventing a stalling indication from the stalling detector during a rescue operation; and moving the elevator car in order to release the safety gears.