Inductive Sensor for Elevator Rotation Speed Measurement

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Solution Overview

Problem

Existing measurement methods for elevator, escalator, and moving walkway components are unreliable due to sensitivity to dirt and potential wheel slippage, requiring extensive scales or mechanical contact, which are costly and prone to errors.

Innovation Solution

A measurement arrangement using an inductive sensor positioned stationary relative to a rotationally unsymmetrical component, allowing different angular positions to generate unique output signals, enabling reliable and cost-effective rotation speed measurement without mechanical contact or sensitivity to dirt.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a linear encoder is used to determine the position and speed of an elevator car, then measurement capability is provided, but the system becomes vulnerable to dirt and requires a scale extending over the whole shaft length

Engineering Contradiction:

Improveposition and speed measurementVSAvoidreliability under dirt conditions

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces mechanical contact-based measurement systems (linear encoders with scales, friction wheels) with a non-contact inductive sensing system. The inductive sensor detects changes in the magnetic field caused by the rotationally unsymmetrical component, enabling measurement without mechanical contact or physical scales, thus eliminating vulnerability to dirt and mechanical wear.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a rotationally unsymmetrical component (such as a gear tooth pattern or magnet arrangement) as an intermediary between the rotating component and the stationary inductive sensor. This intermediary translates rotational position into detectable magnetic field variations, enabling precise measurement without direct contact between the sensor and the rotating component.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If a friction wheel encoder is used to determine speed and position, then measurement is enabled, but wheel slippage occurs making the system unreliable

Engineering Contradiction:

Improvespeed and position measurementVSAvoidreliability under slippage conditions

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent eliminates mechanical friction-based measurement by replacing the friction wheel encoder with a non-contact inductive sensing system. The inductive sensor detects magnetic field changes caused by the rotationally unsymmetrical component, providing measurement without mechanical contact and thus without slippage errors.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If traditional measurement systems are used, then measurement capability is provided, but the system becomes costly and complex

Engineering Contradiction:

Improverotation speed measurementVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the essential measurement function from complex mechanical encoder systems and implements it through a simple non-contact inductive sensor combined with a rotationally unsymmetrical component. This extraction eliminates the need for extensive scales, multiple sensors, and complex mechanical assemblies, reducing overall system complexity and cost.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The rotationally unsymmetrical component serves multiple functions: it acts as both a mechanical element (gear, pulley, or wheel) and a measurement reference feature. This multi-functionality eliminates the need for separate measurement scales or markers, simplifying the system while maintaining measurement capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

The solution provides reliable and inexpensive rotation speed measurement, allowing for accurate determination of component position and speed, reducing the risk of errors and maintenance costs.

Implementation Method 1

an inductive sensor that is arranged stationary in respect of the rotation axis of the component and adjacent to the component or adjacent to a measurement part that is attached to the component in a rotationally fixed manner

Methodology Applied

Scientific EffectInductive sensing: Electromagnetic Induction

Data Source

PatentUS12103817B2Measurement arrangement and method of monitoring rotation speed of a component of an elevator, escalator, moving walkway or moving ramp

Publication Date: 2024.10.01 KONE OYJ

AI summary

The measurement arrangement for measuring the rotation speed of a component of an elevator, escalator, moving walkway or moving ramp comprises an inductive sensor that is arranged stationary in respect of a rotation axis of the component and adjacent to the component or a measurement part that is attached to the component in a rotationally fixed manner, and the component or the measurement part is configured as rotationally unsymmetrical about the rotation axis so that different angular positions of the component about the rotation axis generate different output signals in the inductive sensor.