Elevator Derailment Detection Using Proximity Sensors

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Solution Overview

Problem

Existing elevator systems face challenges in accurately detecting abnormal travel behavior, such as derailment, due to false triggers from wind sway, maintenance concerns, and interference from smoke or dirt, particularly in tall buildings.

Innovation Solution

The implementation of a proximity sensor system mounted on movable bodies within the elevator installation to detect deviations from a predetermined distance to the guide rail, using non-contact sensors like capacitive, inductive, magnetic, or optical sensors, which are connected in series to disrupt an electrical circuit upon detection of derailment, ensuring reliable switching to a secure state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a ring-and-string mechanism is used to detect derailment, then derailment detection capability is improved, but false detections occur due to wind sway in tall buildings

Engineering Contradiction:

Improvederailment detection capabilityVSAvoiddetection accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical ring-and-string contact system with a non-contact proximity sensor system that uses electromagnetic fields (capacitive, inductive, magnetic, or optical) to detect the position of the movable body relative to the guide rail. This substitution eliminates mechanical contact and the associated false detections from wind sway while maintaining derailment detection capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Length of stationary object

If a laser beam mechanism is used to detect derailment, then detection range is improved, but false detections occur due to wind sway and interference from smoke or dirt

Engineering Contradiction:

Improvedetection rangeVSAvoiddetection reliability

Core Design Contradiction:

Length of stationary objectVSReliability

Solution Approach 1:

The patent replaces the laser beam optical system with non-contact proximity sensors that use electromagnetic fields (capacitive, inductive, magnetic, or optical) less susceptible to interference from smoke, dirt, and wind sway. This substitution maintains detection capability while improving reliability in challenging environmental conditions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the detection parameter from optical beam interruption to electromagnetic field interaction (capacitive, inductive, magnetic, or optical proximity sensing). This parameter change makes the detection system less sensitive to environmental factors like smoke, dirt, and wind sway while maintaining the ability to detect derailment conditions.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If a mechanical slider derail detector is used, then derailment detection capability is improved, but additional noise is generated and regular servicing is required

Engineering Contradiction:

Improvederailment detection capabilityVSAvoidmaintenance requirements

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical slider derail detector with non-contact proximity sensors that detect position through electromagnetic fields without mechanical contact. This substitution eliminates wear and tear on moving parts, reduces maintenance requirements, and minimizes noise generation while maintaining derailment detection capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The proximity sensor system requires no regular servicing to maintain mobility or detect wear because it operates without mechanical contact with the guide rail. The sensor mounted on the movable body autonomously detects position changes without requiring external maintenance intervention.

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

This solution provides a robust and flexible derailment detection mechanism that minimizes false alarms and maintains system reliability, unaffected by wind sway or mechanical wear, ensuring passenger safety by accurately identifying and responding to abnormal travel behavior.

Implementation Method 1

a proximity sensor mounted on the movable body to be at a predetermined distance to the guide rail. The proximity sensor is configured to detect whether or not the proximity sensor is at the predetermined distance to the guide rail

Methodology Applied

Scientific EffectProximity sensing: Electromagnetic Induction

Data Source

PatentUS8973715B2Movable body derailment detection system

Publication Date: 2015.03.10 INVENTIO AG

AI summary

An elevator installation has a guide rail of a predetermined length and a movable body configured to move along the guide rail up and down a hoistway. A proximity sensor is mounted on the movable body to be in a predetermined proximity of the guide rail. The proximity sensor is configured to detect whether or not the proximity sensor is at the predetermined distance to the guide rail. A controller coupled to the proximity sensor acts upon an indication that the proximity sensor is not at the predetermined distance to the guide rail to switch the elevator installation to a secure state.