Conveyor Roller Speed Checking for Claw-Mark Prevention

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Claw-marks, or scratches on the tin side of glass produced by speed variability among rollers in float glass production, cause yield losses and disrupt production planning, despite existing systems controlling all rollers with the same gear type.

Innovation Solution

A method involving surface speed measurement devices, such as laser Doppler velocimeters, to measure and correct roller speeds by calculating a correction factor K, comparing roller speeds to a line speed, and analyzing speed variations using statistical methods to identify and address instability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If all rollers are mechanically coupled to the motor with the same type of gears, then all rollers run with the same mean speed, but each roller shows speed variability around this mean value causing claw-marks

Engineering Contradiction:
Improveroller speed consistencyVSAvoidglass surface quality
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent replaces mechanical speed control systems with optical measurement systems (laser Doppler velocimeters) to detect and analyze roller speed variations. This substitution enables precise measurement of speed variability without mechanical intervention, allowing identification of problematic rollers that cause claw-marks on glass surfaces.

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

Solution Approach 2:

The patent implements a feedback mechanism where roller speeds are continuously measured using laser Doppler velocimeters, data is collected and analyzed to calculate speed variability, and this information feeds back into the maintenance and adjustment process. This closed-loop feedback system enables targeted correction of speed variability issues.

Inventive Principle:
Principle #23Feedback

2Productivity

If roller speed variability is not monitored, then production continues without interruption, but claw-mark defects occur causing yield losses and production planning disruptions

Engineering Contradiction:
Improveproduction continuityVSAvoidglass yield
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The patent applies preliminary action by implementing speed measurement and analysis before defects occur. Laser Doppler velocimeters continuously monitor roller speeds and calculate variability metrics in advance, enabling predictive maintenance and adjustment before claw-mark defects manifest on the glass product.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system enables self-service through automated data collection and analysis. The measurement devices automatically capture speed data, the system calculates variability metrics, and generates maintenance recommendations without requiring manual inspection or intervention, allowing production to continue while defects are prevented.

Inventive Principle:
Principle #25Self-service

3Device complexity

If traditional mechanical coupling is used, then device complexity is reduced, but speed variability cannot be detected or corrected

Engineering Contradiction:
Improveroller drive systemVSAvoidroller speed measurement
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces complex mechanical speed control mechanisms with simpler mechanical coupling while introducing optical measurement systems (laser Doppler velocimeters) to detect and measure speed variability. This substitution maintains mechanical simplicity while achieving precise measurement capability.

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

Effectively identifies and corrects roller speed variability, reducing the occurrence of claw-marks and improving production stability by targeted maintenance of rollers.

Implementation Method 1

surface speed measurement device is a laser Doppler measuring device

Methodology Applied
Scientific EffectDoppler effect: Doppler Effect

Data Source

PatentEP4423514B1Method of checking rollers and the motion transmission elements
Publication Date: 2025.09.10 SAINT GOBAIN VITRAGE SA
  • EP4423514B1 patent drawingFigure 1~2
  • EP4423514B1 patent drawingFigure 3~5
  • EP4423514B1 patent drawingFigure 6

AI summary

The present invention relates to a method for checking the rollers of conveying means, said scrolling means being driven to a defined line speed, said method comprising the steps of: - Carrying a surface speed measurement device; - For each of a plurality of rollers, • Pointing the measuring device to a location of a roller to obtain a serial of values representative of the speed for this roller; • Calculating the mean value of the serial of values representative of the speed for this roller • Comparing the mean value representative of the speed for the roller to the line speed so as to obtain a factor K; • Multiplying each value of the serial of values representative of the speed by its factor K to obtain corrected values of speed - using said corrected values representative of the speed to determine the speed variation to check the rollers