Safety Switch Module with Proximity Detection for Actuator Position

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Solution Overview

Problem

Existing safety switches do not meet the requirements of higher safety categories, particularly in recognizing the status of protective devices despite damage, such as actuator breakage, to ensure safe machine shutdown.

Innovation Solution

A module for a safety switch that includes a base body fixed to the safety switch with a receiving opening for a proximity switch, allowing detection of the actuator's position through mechanical coding and electromagnetic interaction, providing dual independent detection methods to ensure accurate status recognition and safe shutdown.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single detection method is used in existing safety switches, then the device complexity is low, but the reliability is insufficient for higher safety categories

Engineering Contradiction:
Improvesafety categoryVSAvoiddetection system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The detection system is segmented into two independent detection channels: a first detection means (mechanical coding recognition) and a second detection means (proximity detection). Each channel independently monitors the actuator position, and both must agree for the safety switch to indicate the protective device is closed. This segmentation provides redundancy and increases reliability without requiring a completely complex integrated system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A module is introduced as an intermediary component that houses the proximity switch and provides the second independent detection channel. This module can be retrofitted onto existing safety switches, adding the necessary redundancy for higher safety categories without redesigning the entire safety switch system. The module serves as a mediator between the actuator and the safety switch's control logic.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the actuator is mechanically coded for precise detection, then the measurement precision is high, but the vulnerability to damage (breakage) increases

Engineering Contradiction:
Improveactuator position detectionVSAvoidactuator breakage
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system prepares for potential actuator breakage by implementing a second detection means that monitors the actuator's position independently of the mechanical coding. The proximity switch detects the actuator's position based on its physical position rather than its mechanical coding, providing a backup detection method that remains functional even if the mechanical coding is damaged or the actuator is partially broken.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The system changes the detection parameter from solely mechanical coding recognition to include both mechanical coding recognition and proximity-based position detection. By using two different detection parameters (mechanical features and physical position), the system ensures that if one parameter becomes unavailable due to actuator damage, the other parameter can still provide accurate status information.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If dual independent detection methods are implemented, then the reliability for higher safety categories is achieved, but the device complexity increases

Engineering Contradiction:
Improvesafety categoryVSAvoiddetection system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The detection system is segmented into two independent detection channels: a first detection means (mechanical coding recognition) and a second detection means (proximity detection). Each channel independently monitors the actuator position, and both must agree for the safety switch to indicate the protective device is closed. This segmentation provides redundancy and increases reliability without requiring a completely complex integrated system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The module designed for the safety switch serves multiple functions: it houses the proximity switch for the second detection channel, provides mounting structure, and integrates with the existing safety switch's electrical and mechanical systems. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving the required dual detection 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 module enhances safety switch performance by enabling detection of the actuator's position in two independent ways, ensuring safe operation even if the actuator is damaged, and can be easily retrofitted into existing safety switches, meeting higher safety standards.

Implementation Method 1

The module has a proximity switch with which a position of the actuator can be detected which corresponds to the state of the first section of the actuator inserted into the head section

Methodology Applied
Scientific EffectProximity detection: Electromagnetic Induction

Data Source

PatentEP2791956B1Module for a safety switch, safety switch having a module of this kind, and operator for a safety switch of this kind
Publication Date: 2016.11.30 EUCHNER GMBH & CO KG
  • EP2791956B1 patent drawingFigure 1~3
  • EP2791956B1 patent drawingFigure 4~5
  • EP2791956B1 patent drawingFigure 6~7

AI summary

The invention relates to a module (1) for a safety switch (1) which has a housing (2) having a head section (4) into which a preferably mechanically encoded first section (22) of an operator (20) can be inserted and, as a result, initiates a switching process in an electrical switch unit of the safety switch (1), characterized in that the module (10) can be secured to the safety switch (1) and has a proximity switch (30) with which a position of the operator (20) can be detected, said position corresponding to the state of the first section (22) of the operator (20) in which it is inserted into the head section (4), and in that the module (10) has an interface to the safety switch (1), by means of which interface a signal which represents the detected position of the operator (20) can be transmitted from the module (10) to the electrical switch unit of the safety switch (1), to a safety switch (1) having a module (10) of this kind, and to an operator (20) for a safety switch (1) of this kind.