Safety Switch Evaluation Unit for Simultaneous Signal Processing

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Solution Overview

Problem

Existing safety switching devices with mechanical enabling buttons can experience unintended emergency shutdowns due to time delays in actuation signals, which can be exacerbated by design flaws or operator errors, leading to unnecessary system shutdowns and increased downtime.

Innovation Solution

An electronic evaluation unit with two detection modules that acquire and process signals from sensors to ensure simultaneous output switching stages are activated only when both modules detect a specific change in actuation information without intermediate changes, minimizing time delays and preventing false emergency shutdowns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple redundant circuits are used in mechanical enabling switches, then safety is improved by preventing single contact failure, but time delays occur when contacts switch simultaneously causing unintended emergency shutdowns

Engineering Contradiction:
ImprovesafetyVSAvoidtime delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces mechanical contact-based switching with an electronic sensor and evaluation unit system. Optical sensors or capacitive touch sensors detect actuator position and generate electronic switching signals, eliminating mechanical contact delays while maintaining safety through redundant evaluation channels that process sensor signals independently and simultaneously.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The evaluation unit dynamically processes sensor signals with defined response times, allowing flexible adjustment of switching behavior. The system can adapt to different actuation scenarios (normal operation vs. panic button) by evaluating signal patterns and timing, enabling simultaneous output signal generation without fixed mechanical contact delays.

Inventive Principle:
Principle #15Dynamics

2Ease of manufacture

If mechanical contacts are used in enabling switches, then the device structure is simple and easy to manufacture, but time delays and unintended shutdowns occur due to contact switching asynchronicity

Engineering Contradiction:
Improvedevice structureVSAvoidswitching precision
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent substitutes mechanical contact switching with electronic signal processing. Sensors (optical or capacitive) detect actuator position and generate electronic signals processed by an evaluation unit, eliminating mechanical contact asynchronicity while maintaining manufacturing simplicity through integrated sensor-evaluator modules.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If the evaluation unit processes signals from multiple sensors independently, then safety is enhanced through redundancy, but time offsets in signal processing may cause false emergency shutdowns

Engineering Contradiction:
Improvesafety redundancyVSAvoidsignal processing time offset
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The evaluation unit merges signals from multiple independent sensor channels through a unified signal processing architecture. The evaluator coordinates the redundant evaluation channels to generate output signals within a defined time window, ensuring simultaneous switching while maintaining the safety benefits of redundant independent signal paths.

Inventive Principle:
Principle #5Merging (Combining)

4Reliability

If mechanical enabling switches are used with redundant contacts, then single contact failure is prevented, but the device complexity increases with multiple circuits and contacts

Engineering Contradiction:
Improvefault toleranceVSAvoidcircuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical contact arrangements with electronic sensor and evaluation unit components. A single actuator controls multiple independent sensor channels that feed into an evaluation unit, achieving fault tolerance through electronic redundancy rather than mechanical contact multiplication, thereby reducing overall device complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP2671690B1Evaluation unit for a safety switch device and safety switch device
Publication Date: 2019.02.20 KEBA AG
  • EP2671690B1 patent drawingFigure 1~2
  • EP2671690B1 patent drawingFigure 3~4
  • EP2671690B1 patent drawingFigure 5

AI summary

The unit (8) has detecting components (15, 16) for detecting respective actuating information (13, 14). The information is derived from a sensor signal (9) and another sensor signal provided by sensors (6, 7) for detecting an actuating condition of a safety switch device (4). The detecting components are arranged such that the detecting components output activation information (17, 18) for controlling output switching stages (19, 20) within a defined limited time displacement when the detecting components directly and successively detect preset changes of the actuating information. The sensors are pressure sensors. Independent claims are also included for the following: (1) a safety switch device (2) a method for operating a safety switch device.