Protective Field Muting via Position-Tracked Marking Elements

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Solution Overview

Problem

Existing monitoring devices in safety technology often trigger unnecessary shutdowns due to inaccurate detection and timing issues with permissible objects passing through protective fields, as current muting sensors struggle to reliably detect and coordinate the movement of these objects, leading to potential safety and operational inefficiencies.

Innovation Solution

The monitoring device employs sensor means to detect the path and movement of movable units, allowing for precise control and monitoring of a bridging function that prevents the safety sensor from triggering when permissible objects pass through the protective field, using incremental and absolute path detection, and adaptable muting based on path, speed, and direction signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If muting sensors are installed upstream of the safety sensor to detect permissible objects, then the safety function can be bypassed for permissible objects, but the muting sensors cannot reliably detect permissible objects leading to inaccurate timing and evaluation

Engineering Contradiction:
Improvereliability of permissible object detectionVSAvoidprecision of object detection timing
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent introduces marking elements as intermediaries attached to permissible objects. These marking elements are specifically designed to be reliably detected by sensor means, serving as a mediator between the permissible objects and the monitoring system. The marking elements provide clear, distinguishable signals that enable accurate detection and timing, resolving the reliability-precision contradiction by creating a dedicated detection interface.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs optical properties of marking elements that differ from the background and permissible objects. The marking elements have specific optical characteristics (reflectivity, absorption, or emission properties) that make them distinctly detectable by the sensor means. This allows the system to reliably identify permissible objects and their positions, solving the detection reliability issue while maintaining precise timing through consistent optical signal characteristics.

Inventive Principle:
Principle #32Color changes

2Productivity

If the safety sensor is bypassed for permissible objects using muting function, then unnecessary machine downtime is prevented, but the system may fail to detect unauthorized objects that should trigger safety shutdown

Engineering Contradiction:
Improvemachine downtime reductionVSAvoidsafety function reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies local quality by creating a selective muting zone that only affects specific areas of the protective field where permissible objects are expected to pass. The bridging function is localized to predetermined regions rather than applying globally, allowing the safety sensor to remain fully operational in other areas. This enables the system to prevent unnecessary shutdowns for permissible objects while maintaining safety monitoring in all other zones.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The protective field is segmented into different functional zones: muting zones where permissible objects are allowed and non-muting zones where safety monitoring remains active. The control unit selectively applies the bridging function to specific beam axes or regions based on the position and type of detected objects. This segmentation allows simultaneous achievement of productivity improvement and safety reliability through spatial differentiation of monitoring strictness.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If conventional light barrier arrangements are used as muting sensors, then the system structure remains simple, but the detection of permissible objects is unreliable

Engineering Contradiction:
Improvesimplicity of muting sensor arrangementVSAvoidreliability of permissible object detection
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces marking elements as intermediaries attached to permissible objects. These marking elements are specifically designed to be reliably detected by sensor means, serving as a mediator between the permissible objects and the monitoring system. The marking elements provide clear, distinguishable signals that enable accurate detection and timing, resolving the reliability-precision contradiction by creating a dedicated detection interface.

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

This solution significantly enhances the reliability and safety of the monitoring system by ensuring that permissible objects can pass through the protective field without triggering the safety function, while maintaining the security of the system by only bridging the necessary areas and detecting any unauthorized interventions.

Implementation Method 1

sensor means for detecting the position of a movable unit by repeatedly detecting marking elements of the movable unit guided into its detection range

Methodology Applied
Scientific EffectOptical detection: Reflection

Implementation Method 2

sensor means are designed in the form of optical, magnetic, inductive or capacitive sensor means

Methodology Applied
Scientific EffectMagnetic detection: Magnetism

Implementation Method 3

The light curtain generates a switching signal whose switching states indicate whether an object is present in the protective field or not

Methodology Applied
Scientific EffectLight beam interruption detection: Absorption (EM radiation)

Data Source

PatentEP3945237B1Monitoring device and method for operating same
Publication Date: 2024.07.17 LEUZE ELECTRONIC GMBH & CO KG
  • EP3945237B1 patent drawingFigure 1~2
  • EP3945237B1 patent drawingFigure 3a
  • EP3945237B1 patent drawingFigure 3b

AI summary

The invention relates to a monitoring device (100) with a sensor (1) by means of which object monitoring is carried out within a protective field (17). Upon detection of an object intrusion within the protective field (17), a safety function is triggered. Furthermore, means for generating a bridging function are provided, by means of which at least a portion (17') of the protective field (17) is bridged, so that an object intrusion within this portion does not trigger the safety function. Sensor means (19, 20) are also provided for detecting the position of a movable unit, in which marking elements of the movable unit, repeatedly moved into the detection area, are detected, the bridging function being controlled and/or monitored based on the position detection.