Light Curtain Muting Based on Lower-Edge Object Detection
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Solution Overview
Problem
Existing monitoring devices in safety technology struggle with accurately distinguishing between permissible and safety-critical objects using light curtains, leading to unnecessary machine standstills and imprecise muting functions due to unreliable detection and timing coordination of external muting sensors.
Innovation Solution
A monitoring device with a light curtain that generates a muting function based on signals from the light curtain itself, allowing for reliable detection of objects extending to the lower edge of the protective field, eliminating the need for external muting sensors and improving the accuracy of permissible object recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external muting sensors are used to detect permissible objects, then the light curtain can be bypassed for permissible objects, but the detection reliability is insufficient and timing coordination is imprecise
Solution Approach 1:
The patent merges the safety monitoring function and the muting function into a single light curtain system. The light curtain serves dual purposes: detecting safety-critical objects that require machine shutdown and detecting permissible objects that should trigger muting. This eliminates the need for separate external muting sensors and their associated timing coordination problems, as both detection functions are performed by the same sensor with direct temporal reference to the protective field.
Solution Approach 2:
The light curtain is designed to perform multiple functions simultaneously: it acts as both a safety sensor for detecting hazardous objects and a muting sensor for detecting permissible objects. By making the safety sensor universal, the system achieves reliable detection of all object types without requiring separate specialized sensors, thereby improving both detection reliability and timing precision.
2Reliability
If external muting sensors are arranged upstream of the safety sensor, then the safety sensor can be bypassed for permissible objects, but the device complexity increases and structural simplicity is lost
Solution Approach 1:
The patent combines the safety monitoring function and the muting function into a single integrated light curtain system. Instead of arranging separate muting sensors upstream of the safety sensor, the light curtain itself performs both functions by detecting objects in the protective field and evaluating whether they are permissible or safety-critical based on their characteristics and position.
Solution Approach 2:
The light curtain is designed as a universal sensor that simultaneously performs safety monitoring and muting detection. This multi-functional approach eliminates the need for additional external muting sensors and their complex upstream arrangement, thereby maintaining structural simplicity while achieving reliable muting function through the same sensor that monitors safety.
3Reliability
If the light curtain detects any object in the protective field, then safety function is triggered, but unnecessary machine standstills occur for permissible objects
Solution Approach 1:
The patent applies local quality by differentiating between different regions or characteristics within the protective field. The evaluation unit analyzes specific properties of detected objects (such as their position, size, shape, or trajectory) to determine whether they are permissible objects that should allow machine continuation or safety-critical objects that require shutdown. This localized differentiation enables the system to maintain high safety reliability while avoiding unnecessary standstills for permissible objects.
Solution Approach 2:
Instead of triggering the safety function for all detected objects and then attempting to mute permissible ones, the system inverts the logic by directly identifying permissible objects and only triggering the safety function for non-permissible objects. This approach eliminates unnecessary machine standstills while maintaining safety reliability by focusing the safety trigger on the specific subset of objects that actually require it.
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 provides a safer and more reliable muting function that prevents unnecessary machine stoppages by accurately differentiating between permissible and safety-critical objects, ensuring that only non-hazardous objects trigger the muting function, thus enhancing the overall safety and efficiency of the monitoring system.
Implementation Method 1
an arrangement of transmitters (3) emitting light beams (2) and an arrangement of receivers (4) receiving light rays (2)
Implementation Method 2
an arrangement of receivers (4) receiving light rays (2)
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a monitoring device (100) with a light curtain (1) comprising an arrangement of light beams (2) emitting transmitters (3) and an arrangement of light beams (2, 2b) receiving receivers (4), wherein the light curtain (1) is designed for object detection within a protective field (17) and includes an evaluation unit in which a safety function can be triggered upon registration of an object (5) in the protective field (17), and means for generating a muting function by means of which the safety function can be overridden. The muting function is generated depending on signals from the light curtain (1). A muting function is only generated if the light curtain (1) detects an object structure extending to the lower edge of the protective field (17).