Light Grid with Dual Resolution for Machine Safety

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Solution Overview

Problem

Existing light grid systems face challenges in versatility and machine safety, as they often require separate setups for different applications and manual reset mechanisms, leading to inefficiencies in productivity due to unclear assessment of hazardous areas and the need for manual intervention.

Innovation Solution

A light grid system with dual resolutions, where the same light grid can detect both partial body interventions and full body access, allowing for optimized machine restart behavior and increased productivity by integrating a control and evaluation unit that adjusts light transmitter and receiver spacing for different detection needs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a light grid with high resolution (14 mm) is installed close to the danger point for primary protection, then detection precision is improved, but device complexity increases due to the need for additional light grids for stepping behind protection

Engineering Contradiction:
Improvedetection precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The light grid is designed to perform multiple functions: primary protection detection, stepping behind protection, and access protection. By making the light grid universal and capable of handling multiple protection tasks simultaneously, the need for separate additional light grids is eliminated, thus reducing device complexity while maintaining high detection precision through the 14 mm resolution

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

Multiple protection functions that previously required separate light grid systems are merged into a single light grid system. The control and evaluation unit integrates the assessment of different hazard scenarios (stepping behind, access, intervention) and coordinates the protection responses, combining multiple functions into one unified device

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If additional light grids are arranged horizontally for stepping behind protection, then safety coverage is improved, but device complexity and installation complexity increase

Engineering Contradiction:
Improvesafety coverageVSAvoidinstallation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The light grid system is designed to provide both primary protection and stepping behind protection through its universal detection capability. The control and evaluation unit assesses different hazard scenarios and triggers appropriate protection responses, eliminating the need for separate additional light grid installations while maintaining comprehensive safety coverage

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If manual reset function is provided by separate manually operated device, then machine safety is improved, but productivity decreases due to manual intervention requirements

Engineering Contradiction:
Improvemachine safetyVSAvoidproductivity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The light grid system with dual resolutions enables self-service operation by automatically detecting when the hazardous area is clear and enabling automatic restart. The system monitors the protective field continuously and can autonomously reset the stop command without requiring manual intervention, thus maintaining machine safety while improving productivity

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The control and evaluation unit continuously monitors the protective field and provides feedback about the presence or absence of objects or persons in the hazardous area. This feedback mechanism enables automatic restart decisions based on real-time detection, eliminating the need for manual reset operations while maintaining safety

Inventive Principle:
Principle #23Feedback

4Measurement precision

If light transmitters and light receivers are arranged equidistantly forming first resolution, then detection precision is improved, but adaptability decreases for different application scenarios

Engineering Contradiction:
Improvedetection precisionVSAvoidadaptability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The light grid system dynamically adjusts its resolution based on the detection scenario. The control and evaluation unit can switch between first resolution (high precision for intervention detection) and second resolution (lower precision for access detection), making the system adaptable to different application scenarios while maintaining the equidistant arrangement of light transmitters and receivers

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes its detection parameter (resolution) based on the application scenario. By switching between first resolution and second resolution in the control and evaluation unit, the light grid adapts to different detection needs without changing its physical structure, thus maintaining versatility across different applications

Inventive Principle:
Principle #35Parameter changes

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 enhances machine safety and productivity by enabling continuous detection of endangered persons, eliminating the need for manual reset in certain situations and allowing for adaptable resolution settings, thus improving operational efficiency.

Implementation Method 1

a transmitting unit with light transmitters (5) emitting light beams (7), with a receiving unit with light receivers (6) receiving light beams (7)

Methodology Applied
Scientific EffectLight: Light

Data Source

PatentEP3444519B1Light grid
Publication Date: 2019.12.11 SICK AG
  • EP3444519B1 patent drawingFigure 1
  • EP3444519B1 patent drawingFigure 2
  • EP3444519B1 patent drawingFigure 3

AI summary

Light grid (4) for detecting objects (2) and/or persons (15) within a monitoring area (3) or protective field, comprising a transmitting unit (12) with light emitters (5) emitting light beams (7), a receiving unit (13) with light receivers (6) receiving light beams (7), and a control and evaluation unit (8) in which object detection signals (9) are generated depending on received signals at the outputs of the light receivers (6), wherein the light emitters (5) and the light receivers (6) are each arranged equidistantly, so that the light emitters (5) and light receivers (6) form a first resolution of the light grid (4), wherein the first resolution is effective in a first area (10) of the light grid (4) and the light emitters (5) and the light receivers (6) are adjustable with a second resolution by the control and evaluation unit (8) in a second area (11) of the light grid (4),where the second resolution is a lower resolution than the first resolution.