Safety Door Control System for False Alarm Reduction

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Solution Overview

Problem

Current safety devices for high-speed industrial doors and gates often generate false alarms, leading to significant productivity losses and downtime due to unnecessary reversals and emergency stop routines, despite being designed to prevent collisions and entrapment.

Innovation Solution

A protective device with a control system that differentiates between two distance ranges, allowing for immediate alarm and reversal in a close range and reduced speed operation in a far range, minimizing false alarms and maintaining high productivity while ensuring safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If safety devices trigger immediate alarm and reversal upon detecting objects in the monitoring area, then collision prevention is improved, but productivity deteriorates due to frequent false alarms and unnecessary interruptions

Engineering Contradiction:
Improvecollision preventionVSAvoidoperational efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The monitoring area is segmented into two distinct zones: a first distance range (close range) and a second distance range (far range). Objects detected in the second range trigger only speed reduction, while objects in the first range trigger alarm and reversal. This segmentation allows the system to differentiate between potential and imminent collision risks, reducing false alarms while maintaining safety.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different safety responses are applied to different spatial locations within the monitoring area. The close range (first distance range) requires immediate alarm and reversal, while the far range (second distance range) requires only speed reduction. This local differentiation optimizes the balance between safety and productivity by applying appropriate response intensity to each zone.

Inventive Principle:
Principle #3Local quality

2Reliability

If safety devices monitor the closing gate to prevent entrapment and collisions, then safety is improved, but downtime increases due to alarm routines and emergency stops

Engineering Contradiction:
ImprovesafetyVSAvoiddowntime
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary speed reduction when objects are detected in the second distance range (far range) before they reach the critical first distance range (close range). This preliminary action prevents many potential collisions from escalating to alarm conditions, thereby reducing unnecessary downtime while maintaining safety.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The gate closing speed is dynamically adjusted based on object detection location. In the second range, speed is reduced but operation continues; in the first range, immediate reversal occurs. This dynamic response optimizes the balance between safety intervention and operational continuity, minimizing downtime.

Inventive Principle:
Principle #15Dynamics

3Productivity

If high-speed gates operate at closing speeds greater than 0.5 m/s, then productivity is improved, but safety risks increase due to reduced reaction time for collision prevention

Engineering Contradiction:
Improveclosing speedVSAvoidcollision prevention
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The extended monitoring area (second distance range) enables preliminary detection and speed reduction before the gate reaches high-speed closing phase. This gives the system more time to react to objects, allowing high-speed operation while maintaining safety through early intervention.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The monitoring device provides continuous feedback about objects in the monitoring area, enabling real-time adjustment of gate speed. This feedback mechanism allows the gate to operate at high speed when safe, while automatically reducing speed or reversing when objects are detected, thus maintaining both productivity and safety.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3584400B1Safety door and method for operating a safety door
Publication Date: 2023.05.10 ITW INDTORE
  • EP3584400B1 patent drawingFigure 1
  • EP3584400B1 patent drawingFigure 2
  • EP3584400B1 patent drawingFigure 3~4

AI summary

The disclosure relates to a protective device (10, 110, 210, 310) in the form of a protective door or gate (12) for a plant (14), in particular a production plant, with a closing element (26, 126, 226, 326), in particular a high-speed closing element (26, 126, 226, 326), with a closing edge (28, 128, 228, 328), wherein the closing element (26, 126, 226, 326) is movable in a closing plane (18) between an open position and a closed position, a drive (38, 138) for driving the closing element (26, 126, 226, 326), a monitoring device (64, 164, 264, 364) with at least one sensor unit (66, 166, 266, 366), which monitors an area (72) of the closing level (18) to detect the intrusion of foreign objects (194, 196, 198, 296, 396) into a security zone (176, 276, 376), and with a control unit (50, 150) designed to control the drive (38, 138) based on data,which are provided by the monitoring device, depending on whether a detected foreign object (194, 196, 198, 296, 396) is located within the safety zone (176, 276, 376) in a first distance range (178, 278, 378) or a second distance range (180, 280, 380), to operate selectively in a first operating mode or in a second operating mode. The disclosure further relates to a use and a method for operating a protective device (10, 110, 210, 310),