Optical Safety Sensor Fields for Integrated Muting Control
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Solution Overview
Problem
Existing safety devices with light curtains face increased design complexity and safety impairments due to the need for external muting sensors, which can fail to detect safety-critical objects when permissible objects with smaller widths are conveyed, leading to unacceptable safety risks.
Innovation Solution
A safety device with integrated optical safety sensors that utilize both protective and signal fields, allowing for the detection of permissible objects without external sensors, enabling adaptive geometry and timing to ensure safe passage without compromising safety, by activating signal fields tailored to the dimensions and speed of permissible objects, thus maintaining high safety standards and machine availability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If external muting sensors are added to allow permissible objects to pass through the monitoring area, then machine availability is improved, but device complexity increases and safety function is impaired
Solution Approach 1:
The patent combines the muting function and safety monitoring function into a single integrated safety sensor system. The optical safety sensor includes both a light curtain for safety monitoring and muting sensors arranged upstream, all controlled by a single control unit. This merging eliminates the need for separate external muting sensors while maintaining both safety and productivity functions.
Solution Approach 2:
The safety sensor is designed to perform multiple functions: it acts as both a safety monitoring device (light curtain) and a muting device simultaneously. The control unit evaluates signals from both the light curtain and muting sensors to determine whether to generate safety signals or suppress them, making the single device universal in its safety-related functions.
2Productivity
If external muting sensors are added to allow permissible objects to pass through, then machine availability is improved, but safety function is impaired due to inability to detect safety-critical objects
Solution Approach 1:
The patent applies different monitoring characteristics to different spatial zones. The light curtain provides safety monitoring across the entire monitoring area, while muting sensors provide selective suppression only in specific zones where permissible objects pass. This local differentiation allows the system to tolerate permissible objects while maintaining sensitivity to safety-critical objects.
Solution Approach 2:
The control unit continuously evaluates signals from both the light curtain and muting sensors to dynamically determine whether to generate or suppress safety signals. This feedback mechanism ensures that safety-critical objects are detected even when muting is active for permissible objects, maintaining safety function while allowing productivity.
3Productivity
If the light curtain is muted to allow permissible objects to pass, then machine availability is improved, but the entire width of the monitoring area is affected, causing safety-critical objects to go undetected
Solution Approach 1:
The patent segments the monitoring area into distinct zones: a muting area where permissible objects pass and safety signals are suppressed, and a non-muted monitoring area where the light curtain remains active for safety detection. This segmentation allows the muting function to be localized to specific regions rather than affecting the entire monitoring area, preserving safety coverage.
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 fail-safe monitoring function that ensures safety-critical objects are detected while allowing non-critical objects to pass through without triggering unnecessary shutdowns, enhancing safety and machine availability by integrating signal and protective field management within the safety sensors themselves.
Implementation Method 1
An object is detected by recognizing whether the beam path of at least one of the light beams is interrupted
Data Source
Figure 1~4
Figure 2~3
Figure 5a~5b
AI summary
The invention relates to a safety device (1) with at least one optical safety sensor (2) designed to monitor a planar or spatial monitoring area (3). The safety device (1) further comprises a safety output circuit associated with the safety sensor (2), the circuit having an arrangement of safety outputs controlled by signals from the safety sensor (2). Switching means are provided by means of which at least one protective field (5) and/or at least one signal field (18) can be activated. The safety sensor (2) generates a safety signal in the form of a deactivation of the safety outputs (16) if the safety sensor (2) detects an object within the activated protective field (5), or if no permissible object (17) is detected within the activated signal field (18) within a predetermined time interval.