Slender Bar Straightness Measurement with Gravity Deformation Compensation

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Solution Overview

Problem

Current methods for measuring straightness errors in metal bars during production are inefficient, prone to measurement errors due to gravity deformation, and unsuitable for high-speed production lines, as they require long measurement times, are inaccurate, or involve complex mechanical adjustments.

Innovation Solution

A static bar supporting system with optical sensors and force transducers that detect the bar's tridimensional geometry and forces, allowing for accurate compensation of gravity-induced deformations and enabling rapid, precise straightness error measurement across various geometric sections and lengths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional rotation method with comparator is used to measure straightness error, then measurement accuracy is improved, but measurement time increases significantly making it unsuitable for production lines

Engineering Contradiction:
Improvestraightness error measurement accuracyVSAvoidmeasurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the traditional mechanical rotation and comparator system with an optical measurement system using lasers and sensors. The bar is measured in a static position using optical fields instead of mechanical rotation, eliminating the time-consuming mechanical operations while maintaining measurement accuracy through optical detection methods.

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

Solution Approach 2:

The patent applies preliminary compensation for gravity deformation by calculating and subtracting the expected gravitational effect from the measured data. This allows the system to obtain accurate straightness error measurements without requiring the bar to be in a specific orientation or position, enabling rapid measurement on production lines.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If laser sensors are used to measure waviness on the production line, then measurement speed is improved, but measurement accuracy deteriorates due to material deformations and oscillations caused by speed and drive system

Engineering Contradiction:
Improvemeasurement speedVSAvoidwaviness measurement accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent uses optical fields (lasers) instead of mechanical contact sensors to measure the bar. This non-contact method eliminates friction and mechanical disturbances that affect accuracy, while maintaining high measurement speed suitable for production lines. The optical system detects bar geometry without physical interaction that could cause oscillations.

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

Solution Approach 2:

The patent converts the harmful effect of gravity-induced deformation into a beneficial compensation mechanism. By measuring the actual deformation forces and using elastic theory to calculate and subtract the gravitational component, the system transforms the source of measurement error into a correctable parameter, achieving high accuracy despite the bar being in a static supported position.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Adaptability or versatility

If contact sensors with rolling surface are used to estimate curvature, then measurement capability is improved, but measurement accuracy deteriorates due to friction and unpredictable rolling of the material

Engineering Contradiction:
Improvecurvature measurement capabilityVSAvoidcurvature measurement accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent replaces mechanical contact sensors with optical detection systems. Lasers and position sensors detect the bar's geometry non-contactually, eliminating friction and rolling uncertainties that plague mechanical systems. This allows accurate curvature and straightness measurement without the material disturbances caused by mechanical interaction.

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

4Measurement precision

If devices measuring straightness error are used, then measurement capability is improved, but accuracy deteriorates due to uncompensated gravity-induced deformation of slender bodies

Engineering Contradiction:
Improvestraightness error measurement capabilityVSAvoidmeasurement accuracy for slender bodies
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent performs preliminary compensation for gravity deformation by calculating the expected gravitational effect on the slender bar and subtracting it from the measured data. This allows accurate straightness error measurement even when the bar is in a static position under its own weight, making the system reliable for slender bodies that are particularly susceptible to gravitational deformation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent transforms the harmful gravity-induced deformation into a measurable and compensatable parameter. By using force transducers to detect the actual gravitational effect and applying elastic theory to calculate the deformation, the system converts the source of error into correctable information, achieving high reliability for measuring slender bodies.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

The solution enables fast, accurate measurement of straightness errors on production lines, compensating for gravity-induced deformations and providing precise results, even for slender bodies, thus improving production efficiency and compliance with quality standards.

Implementation Method 1

a first detecting system (5) to detect the development of the longitudinal axis of the bar (2) and comprising one or more first sensors (6), namely optical sensors

Methodology Applied
Scientific EffectOptical detection: Light

Implementation Method 2

a second detecting system (7) to detect vectors of forces acting on the bar and comprising a plurality of second sensors (7A) combined with each bearing element (4)

Methodology Applied
Scientific EffectForce detection: Force

Implementation Method 3

The supporting system (3), therefore, static during the measuring step of the bar (2)... allowing for accurate compensation of gravity-induced deformations

Methodology Applied
Scientific EffectGravity compensation: Gravitation

Data Source

PatentEP3701220B1Method and apparatus for measuring the straightness error of slender bodies with compensation of gravity deformation
Publication Date: 2023.08.30 Q TECH CO LTD
  • EP3701220B1 patent drawingFigure 1~2
  • EP3701220B1 patent drawingFigure 3a~4
  • EP3701220B1 patent drawingFigure 5~6

AI summary

The present invention concerns an apparatus and a relative method for measuring straightness errors of elongated-shape elements, such as bars, tubes and the like. The measuring apparatus (1) comprises a supporting system (3) for a bar, a first detecting system (5) having one or more first sensors (6) to detect the development of the longitudinal axis of the bar, and a central control unit (9). The measuring apparatus further comprises a second detecting system (7) provided with a plurality of second sensors (7A) to detect the forces the bar applies to the supporting system (3) and acquiring means (10) to acquire at least one physical parameter of the bar under measuring. The central control unit (9) comprises at least one data acquiring and processing module (9') to acquire and process the data detected by said first and second detecting systems (5, 7) and acquired by said acquiring means, in order to determine the possible straightness error of the bar (2).