Worker Island Monitoring for Automated Hazard Protection

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Solution Overview

Problem

Conventional safety systems in industrial environments struggle to reliably protect workers from machine hazards due to difficulties in detecting people in complex and interfered-with areas, leading to potential injuries and system delays, as they require manual monitoring and are prone to errors and interference.

Innovation Solution

A security device that monitors the number and position of people within a controlled worker island area, using a combination of optoelectronic sensors and redundant systems like RFID readers, ensuring automated and reliable protection by preventing unauthorized access and tracking personnel movements, thus eliminating the need for manual checks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If optical sensors are used to monitor the danger area, then automated protection is achieved, but reliability deteriorates due to interference from sawdust, welding sparks, rain, fog, or snow

Engineering Contradiction:
Improveautomated protectionVSAvoiddetection reliability
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

Instead of monitoring the danger area directly with sensors that are vulnerable to environmental interference, the patent inverts the approach by monitoring the worker island (safe area) to determine if workers are present in the danger zone. This indirect monitoring method avoids the reliability issues caused by sawdust, welding sparks, rain, fog, and snow that plague direct optical sensing in the hazard area.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent introduces an intermediary approach where the worker island monitoring system acts as a mediator between the safe worker area and the dangerous machine area. By counting workers on the worker island and comparing this to the total number of workers in the system, the patent indirectly determines danger zone occupancy without requiring direct sensing in the interfered-with danger area.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If manual monitoring of the danger area is required, then detection accuracy improves, but productivity deteriorates due to increased cycle time

Engineering Contradiction:
Improvedetection accuracyVSAvoidprocess cycle time
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The system performs self-service by automatically monitoring worker positions through the worker island counting system and autonomously determining whether machine operation is safe. This eliminates the need for manual monitoring while maintaining high detection accuracy, thereby resolving the contradiction between precision and productivity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent implements a feedback mechanism where the worker island monitoring system continuously provides information about worker positions to the control system. This automated feedback loop enables real-time safety decisions without manual intervention, maintaining high detection accuracy while significantly reducing cycle time compared to manual monitoring procedures.

Inventive Principle:
Principle #23Feedback

3Reliability

If workers must visually check the danger area before startup, then safety improves, but productivity deteriorates due to monotony and decreased concentration

Engineering Contradiction:
ImprovesafetyVSAvoidcycle time
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces the mechanical/manual visual checking process with an automated optical/electronic monitoring system. The worker island monitoring system automatically detects and counts workers, eliminating the need for manual visual inspection. This substitution maintains safety while removing the productivity penalties associated with worker fatigue and decreased concentration during repetitive manual checks.

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

4Reliability

If mechanical protection is implemented, then worker protection improves, but adaptability deteriorates due to restricted system flexibility

Engineering Contradiction:
Improveworker protectionVSAvoidsystem flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces mechanical protection systems (such as physical barriers and interlocked guards) with an automated monitoring system based on worker island detection. This substitution maintains worker protection through automated safety decisions while significantly improving system flexibility and adaptability, allowing the system to respond dynamically to different operational conditions without physical reconfiguration.

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

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 provides reliable and automated startup of systems in challenging environments, optimizing process cycle times and preventing injuries by ensuring all personnel are safely positioned before machine operation, while reducing the risk of errors and interference.

Implementation Method 1

The worker island monitoring device (22) has an optoelectronic sensor (24a-b)

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Implementation Method 2

The worker island monitoring device (22) has an RFID reader (26a-b)

Methodology Applied
Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Data Source

PatentEP2282106B1Securing an area which can only be accessed through one secure access sluice
Publication Date: 2011.09.07 SICK AG
  • EP2282106B1 patent drawingFigure 1
  • EP2282106B1 patent drawingFigure 2~3
  • EP2282106B1 patent drawingFigure 4~5

AI summary

The device has worker islands (20a-c) provided in a spatial region (10) in which persons (14a-e) are not at risk. Worker island-monitoring devices (22a, 22b) determine presence and number of persons on the worker island. A switch-off output outputs a switch-off signal at hazard sources (16a-c) when the persons are not in the spatial region on the hazard sources. The monitoring devices include optoelectronic sensor units (24a, 24b). The sensor unit includes a laser scanner e.g. three-dimensional laser scanner and distance-measuring two-dimensional laser scanner. An independent claim is also included for a method for securing persons in a spatial region.