Elevator Rescue Control Using Gravity Stop at Landing Doors

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Solution Overview

Problem

Existing elevator systems fail to effectively prevent passengers from being trapped due to safety switch or non-safety function unit failures, despite improved safety measures.

Innovation Solution

An elevator safety control device with an interface unit and safety controller that determines abnormal events by analyzing status signals from safety switches and non-safety function units, enabling the car to travel by gravity and stop at the nearest landing door using a holding brake device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If safety switches and non-safety function units are improved to high safety performance, then safety performance is improved, but passengers can still be trapped in the elevator

Engineering Contradiction:

Improvesafety performanceVSAvoidpassenger trapping

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary actions by continuously monitoring the status of safety switches and non-safety function units before trapping occurs. When an abnormal event is detected (such as a safety switch triggering or non-safety unit failure), the system proactively executes the rescue mode to move the car to the nearest landing door, preventing passengers from being trapped rather than reacting after trapping occurs.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by continuously receiving status signals from safety switches and non-safety function units, analyzing these signals to determine abnormal events, and adjusting the rescue operation based on real-time feedback. The safety controller monitors the car's position and landing door status during the rescue operation, making real-time adjustments to ensure safe delivery at the nearest landing door.

Inventive Principle:

Principle #23Feedback

2Reliability

If the elevator system continuously monitors safety status, then abnormal events can be detected timely, but system complexity increases

Engineering Contradiction:

Improveabnormal event detectionVSAvoidmonitoring system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The safety controller serves multiple functions: it receives status signals from both safety switches and non-safety function units, analyzes these signals to detect abnormal events, determines the nearest landing door, and controls the rescue operation. This multi-functionality reduces the need for separate dedicated monitoring components, thereby limiting the increase in system complexity while maintaining comprehensive monitoring capabilities.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system merges the monitoring, analysis, and control functions into a unified safety controller. By combining these functions in a single device rather than distributing them across multiple separate components, the system achieves timely abnormal event detection while minimizing the overall complexity of the monitoring system architecture.

Inventive Principle:

Principle #5Merging (Combining)

3Loss of time

If the car moves by gravity to the nearest landing door, then rescue time is reduced, but control precision requirements increase

Engineering Contradiction:

Improverescue timeVSAvoidlanding door stopping precision

Core Design Contradiction:

Loss of timeVSManufacturing precision

Solution Approach 1:

The system replaces the traditional mechanical braking system with a gravity-based rescue mechanism. Instead of using brakes to control the car's descent, the system allows the car to move downward by gravity, significantly reducing the time required to reach the nearest landing door. The holding brake device is only used to ensure the car stops precisely at the landing door after the gravity-driven movement, minimizing the precision requirements during the bulk of the rescue operation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Facilitates timely rescue of trapped passengers by ensuring the elevator car safely reaches the nearest landing door, even in the event of system failures.

Implementation Method 1

the car is caused to travel by gravity and stop at the landing door of the nearest floor by controlling a state of a holding brake device

Methodology Applied

Scientific EffectGravity: Gravitation

Data Source

PatentUS20260015205A1Elevator safety control device, method for elevator safety control and elevator system

Publication Date: 2026.01.15 OTIS ELEVATOR CO

AI summary

An elevator safety control device includes an interface unit that receives a first status signal of a first safety switch, a second status signal of a second safety switch, and a third status signal of a non-safety function unit of an elevator, the second safety switch including a plurality of landing door switches whose status can be determined individually; a safety controller that performs: determining an occurrence of an abnormal event based on the first status signal, the second status signal and the third status signal; determining, after determining the occurrence of the abnormal event, a possibility of a target landing door based on the second status signal; and executing a rescue mode after determining an existence of the possibility, wherein in the rescue mode, the car is caused to travel by gravity and stop at the target landing door by controlling a state of a holding brake device.