Electromagnet Locking Device Integrated Sensor Monitoring

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Solution Overview

Problem

Existing locking devices with magnetic proximity sensors face challenges in achieving strong holding forces and reliable monitoring, often requiring two magnets and being sensitive to environmental factors, with reed switches being insufficient to actuate in the open state.

Innovation Solution

A locking device equipped with an electromagnet, a core, and a yoke, where an electrical or electronic switching element, such as a reed switch, Hall sensor, or relay, is strategically placed to monitor the magnetic field and detect air gaps, allowing for high holding forces and reliable monitoring of the locking status.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a magnetic field sensor is placed adjacent to the contact surface between the magnet and yoke to detect the magnetic field for monitoring the locking status, then the monitoring precision is improved, but the device complexity increases due to separate mounting of the sensor

Engineering Contradiction:
Improvemonitoring precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent integrates the magnetic field sensor directly into the magnetic circuit of the electromagnet, merging the monitoring function with the locking mechanism structure. This eliminates the need for separate mounting of the sensor and reduces device complexity while maintaining monitoring precision through direct measurement at the contact surface.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If two permanent magnets are used to generate holding force and actuate a reed switch for monitoring, then the monitoring function is achieved, but the holding force is limited and the device size increases

Engineering Contradiction:
Improvemonitoring reliabilityVSAvoidholding force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The patent makes the electromagnet serve dual functions: generating the holding force for locking and providing the magnetic field for monitoring through its integrated sensor. This eliminates the need for separate permanent magnets and allows the electromagnet to provide both locking force and monitoring capability, increasing holding force while reducing device size.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent extracts the monitoring function from a separate sensor system and integrates it directly into the electromagnet's magnetic circuit. This allows the electromagnet to provide both the holding force and the magnetic field necessary for monitoring, eliminating the need for additional permanent magnets and reducing overall device size.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If reed switches are used for monitoring the magnetic field in existing locking devices, then the monitoring function is achieved, but the device is sensitive to environmental factors and requires two magnets

Engineering Contradiction:
Improvemonitoring reliabilityVSAvoidenvironmental sensitivity
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses the electromagnet's own magnetic field as an intermediary for monitoring, rather than relying on external permanent magnets and reed switches. The integrated magnetic field sensor directly measures the magnetic field generated by the electromagnet itself, making the system less sensitive to environmental factors and eliminating the need for additional magnetic components.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 enables a compact, reliable locking device capable of generating significant holding forces and accurately monitoring its status, ensuring the locking mechanism is securely engaged or disengaged, with improved resistance to environmental influences.

Implementation Method 1

a locking device (11) of this kind has a core (17), a coil (15) and a yoke (19), which closes the magnetic circuit of the electromagnet and can be removed from the core

Methodology Applied
Scientific EffectElectromagnet: Electromagnet

Implementation Method 2

The coil (15) can be connected to a voltage source to operate the electromagnet (13)

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 3

An alternative or additional switching element for monitoring the magnetic flux density in the magnetic circuit can be formed by a Hall sensor

Methodology Applied
Scientific EffectHall Effect: Hall Effect

Data Source

PatentEP1867820B1Closing device which can be monitored
Publication Date: 2009.06.03 PILZ AUSLANDSBETEILIGUNGEN
  • EP1867820B1 patent drawingFigure 1
  • EP1867820B1 patent drawingFigure 2~3
  • EP1867820B1 patent drawing

AI summary

An electromagnet (13) has yoke (19) moved away from core (17). The yoke closes magnetic circuit of the electromagnet. An electrical or electronic switching device such as Hall sensor (25) responds to magnetic field of the magnetic circuit. The switching device taps the core or yoke at two sites (31,33) which are spaced apart from one another along lengthwise direction of magnetic flux. A reed switch (23) is located in the core or yoke along lengthwise direction of magnetic circuit.