RFID Locking Sensor Layout for Three-Direction Tongue Detection

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Solution Overview

Problem

Industrial safety locking systems face challenges in accommodating multiple directions of approach for locking tongues without requiring rotation of the locking switch or its components, leading to installation complexities and potential safety hazards due to limited sensing distances of RFID coils.

Innovation Solution

The implementation of a locking switch with three entry slots on adjacent sides of its housing, featuring a solenoid-actuated locking bolt and an inductive coil that generates a second sensing field, along with two RFID coils that detect an RFID tag, where the second RFID coil has reversed polarity to enhance sensing distance and reduce interference, allowing detection from multiple directions without rotating the switch.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a locking switch is designed to accommodate multiple directions of approach, then installation flexibility is improved, but device complexity increases due to multiple entry slots and sensor configurations

Engineering Contradiction:
Improveinstallation flexibilityVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The sensor assembly is designed to perform multiple functions: detecting locking tongues from three different directions using three RFID coils, and detecting locking bolt advancement using an inductive coil. This multi-functional design allows a single sensor assembly to replace what would otherwise require multiple separate sensors, accommodating multiple installation configurations without proportionally increasing complexity

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

Solution Approach 2:

Multiple sensing functions are merged into a single sensor assembly housing. The three RFID coils for directional tongue detection and the inductive coil for bolt detection are integrated into one unified assembly, allowing simultaneous multi-directional monitoring while maintaining a compact, manageable device structure

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If RFID coils are positioned to detect locking tongue from multiple directions, then detection reliability is improved, but sensing field interference increases between coils

Engineering Contradiction:
Improvedetection reliabilityVSAvoidsensing field interference
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The RFID coils are positioned asymmetrically at tilted angles (30-45 degrees) relative to the sensor housing, with each coil oriented to detect locking tongues approaching from different directions. This asymmetric angular arrangement allows each coil to have its own optimized detection sector, reducing overlapping sensing fields and minimizing interference between coils while maintaining comprehensive multi-directional coverage

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

Each RFID coil is given a specific localized function by tilting it at a different angle and orienting it toward a specific entry direction. The first RFID coil detects tongues from one direction, the second from another, and the third from a third direction. This local specialization of each coil's detection zone reduces sensing field overlap and interference while ensuring reliable detection from multiple directions

Inventive Principle:
Principle #3Local quality

3Measurement precision

If inductive coil generates sensing field for bolt detection, then bolt detection capability is improved, but premature detection of locking tongue increases

Engineering Contradiction:
Improvebolt detection capabilityVSAvoidpremature detection
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system uses frequency differentiation to distinguish between the locking tongue and locking bolt. RFID coils operating at RFID frequencies detect the locking tongue, while the inductive coil operates at inductive sensing frequencies to detect the locking bolt. By changing the operating frequency parameter of different coils, the system can selectively detect different components without premature or false detection, ensuring accurate sequencing of detection events

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

This configuration enables flexible installation by detecting the locking tongue from various approaches without rotating the switch, extends the sensing distance of RFID coils, and ensures reliable engagement of the locking bolt, enhancing safety and installation ease.

Implementation Method 1

an inductive coil that generates a second sensing field about a second sensing field axis at a second frequency and that detects advancement of the locking bolt

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

at least two radio frequency identifier (RFID) coils that generate a first sensing field at a first frequency that detects an RFID tag

Methodology Applied
Scientific EffectElectromagnetic coupling: Electromagnetic Induction

Data Source

PatentEP3745439B1Sensor with three concurrent directions of approach
Publication Date: 2024.06.05 ROCKWELL AUTOMATION TECH INC
  • EP3745439B1 patent drawingFigure 1
  • EP3745439B1 patent drawingFigure 2a~2c
  • EP3745439B1 patent drawingFigure 3

AI summary

For locking industrial safety guarding, a sensor includes an inductive coil that generates a second sensing field about a second sensing field axis at a second frequency that detects advancement of a locking bolt. The sensor further includes at least two radio frequency identifier (RFID) coils that generate a first sensing field at a first frequency that detects an RFID tag. A second RFID coil of the at least two RFID coils has a second polarity reversed from a first polarity a first RFID coil of the at least two RFID coils and reduces the first sensing field at the second sensing field axis.