Derailment Detection Device Using Magnetic Force Measurement

Solution Overview

Problem

Existing derailment detection devices for railway vehicles are expensive and heavy due to the use of inductive sensors, making them inefficient for timely and cost-effective derailment detection.

Innovation Solution

A derailment detection device comprising a magnetic assembly with permanent magnets and a load cell to measure magnetic force between the rail and the assembly, with an electronic processing module comparing the force to a threshold and emitting an alert signal for emergency braking when the force drops below the threshold.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an inductive sensor is used for derailment detection, then the detection reliability is improved, but the device weight and cost increase significantly

Engineering Contradiction:

Improvederailment detection reliabilityVSAvoiddevice weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent replaces the inductive sensor (electromagnetic system) with a magnetic field-based detection system using permanent magnets and Hall sensors. This substitution maintains detection reliability while significantly reducing device complexity, weight, and cost by eliminating the need for powered inductive sensors and their associated electronics.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses inexpensive permanent magnets and simple Hall sensors instead of expensive inductive sensors. The magnetic assembly with permanent magnets creates a detectable magnetic field that can be sensed by simple Hall sensors, providing a cost-effective alternative that maintains functional reliability for derailment detection.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Reliability

If an inductive sensor is used for derailment detection, then the detection reliability is improved, but the device cost increases significantly

Engineering Contradiction:

Improvederailment detection reliabilityVSAvoiddevice cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses inexpensive permanent magnets and simple Hall sensors instead of expensive inductive sensors. The magnetic assembly with permanent magnets creates a detectable magnetic field that can be sensed by simple Hall sensors, providing a cost-effective alternative that maintains functional reliability for derailment detection.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent replaces the inductive sensor (electromagnetic system) with a magnetic field-based detection system using permanent magnets and Hall sensors. This substitution maintains detection reliability while significantly reducing device complexity, weight, and cost by eliminating the need for powered inductive sensors and their associated electronics.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If the magnetic force threshold is set low for sensitive detection, then the detection sensitivity is improved, but false alarms increase

Engineering Contradiction:

Improvemagnetic force measurement sensitivityVSAvoidfalse alarm rate

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent employs a threshold comparison mechanism where the measured magnetic force is continuously monitored against a predetermined threshold value. When the magnetic force exceeds the threshold (indicating derailment), an alert signal is generated. This feedback-based thresholding provides clear decision criteria that reduce false alarms while maintaining detection sensitivity.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent changes the detection parameter from indirect inductive measurements to direct magnetic force measurements using Hall sensors. This parameter change provides a more stable and reliable measurement that is less susceptible to false readings, enabling effective threshold-based detection with reduced false alarm rates.

Inventive Principle:

Principle #35Parameter changes

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 a cost-effective and lightweight derailment detection system that ensures timely detection and prevention of derailments, reducing material damage and bodily harm while maintaining high safety standards.

Implementation Method 1

a magnetic assembly comprising at least one magnet and configured to be disposed faced to one of the rails

Methodology Applied

Scientific EffectMagnetism: Magnetism

Implementation Method 2

the rail being made of a ferromagnetic material

Methodology Applied

Scientific EffectFerromagnetism: Ferromagnetism

Implementation Method 3

the sensor being made as a load cell

Methodology Applied

Scientific EffectPiezoresistive effect: Piezoresistive Effect

Data Source

PatentEP3623250B1Derailment detection device and associated railway vehicle and method

Publication Date: 2020.12.02 ALSTOM TRANSPORT TECH SAS

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AI summary

The inventions concerns a derailment detection device (26) configured to be provided onboard a railway vehicle configured to move on rails (20) of a railway track (22). The derailment detection (26) device comprises: - a magnetic assembly comprising at least one magnet and configured to be disposed faced to one of the rails (20) ; - a sensor (30) configured to measure a magnetic force (F) between the rail (20) and the magnetic assembly ; and - an electronic processing module configured to compare the measured magnetic force to a predetermined threshold value and to emit an alert signal when the measured magnetic force is lower than the threshold value.