Light Curtain Muting for Single-Object Safety Detection
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Solution Overview
Problem
Existing sensor arrangements for danger area monitoring often fail to accurately distinguish between permissible and safety-critical objects, leading to uncontrolled situations where safety-critical objects can pass undetected, as current muting methods are prone to gaps in detection and require additional sensors or complex configurations.
Innovation Solution
A sensor arrangement with a light curtain that activates muting only when exactly one permissible object is detected, utilizing an arrangement of holes to guide light beams without interruption, allowing for precise detection and recognition of permissible objects, and enabling partial or complete bridging of the monitoring function to prevent safety-critical objects from triggering the safety function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If muting function is activated to allow permissible objects to pass through the light curtain, then productivity is improved by avoiding unnecessary safety function triggers, but reliability deteriorates because gaps can occur where safety-critical objects pass undetected
Solution Approach 1:
The patent segments the object detection process into multiple light beams arranged in a curtain, where each beam independently monitors a specific zone. The evaluation unit analyzes the pattern of interrupted beams to determine object characteristics, enabling differentiation between permissible objects (which interrupt specific beam patterns) and safety-critical objects (which create different interruption patterns). This segmentation allows the muting function to be activated selectively for permissible objects while maintaining safety monitoring for other objects.
2Reliability
If additional sensors are added to improve detection accuracy and eliminate gaps in the monitoring function, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent uses an array of light beams that provides more detection zones than the minimum single beam would provide. This excessive action creates overlapping monitoring zones and multiple interruption patterns that enable the system to differentiate between object types using sophisticated evaluation algorithms, thereby improving reliability without adding physical sensors beyond the light curtain components.
3Ease of operation
If the monitoring function is completely overridden for permissible objects, then ease of operation is improved by allowing smooth passage, but safety is compromised as safety-critical objects cannot be distinguished
Solution Approach 1:
The evaluation unit continuously analyzes the pattern of light beam interruptions in real-time, comparing the detected pattern against stored characteristics of permissible and safety-critical objects. Based on this feedback analysis, the system selectively activates the muting function only when the pattern matches that of a permissible object, allowing smooth passage while maintaining safety monitoring for objects with different characteristics. This feedback mechanism enables dynamic adjustment of the monitoring function based on actual object detection.
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
Significantly enhances safety by ensuring that only permissible objects can pass through the monitored area without triggering the safety function, preventing safety-critical objects from entering the danger zone, and allowing for flexible operation with various muting systems without additional sensors or complex parameterization.
Implementation Method 1
at least one light curtain, which typically has a series arrangement of light beam emitting transmitters in a first housing and a series arrangement of light beam receiving receivers in a second housing
Implementation Method 2
The permissible object has an arrangement of holes, wherein light beams guided in the holes are not interrupted
Data Source
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AI summary
The invention relates to a sensor arrangement (1) with at least one light curtain (8) designed to monitor at least one protective field (7). A monitoring function is provided such that, when an object enters the protective field (7), a switching signal is generated by means of which a safety function can be triggered. A muting function is also provided, by means of which the monitoring function can be at least partially overridden. The muting function is only activated if exactly one permissible object is detected within the protective field (7). The invention further relates to a corresponding method.