Spring-Loaded Scratch Tester for Glass

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Solution Overview

Problem

Existing methods for scratch testing glass surfaces face challenges in achieving reproducible results due to the high surface hardness and brittleness of glass, as well as the difficulty in applying a constant force without causing microcracks or hairline cracks that can affect the stability and strength of the glass.

Innovation Solution

A scratch tester comprising a hollow scraper cylinder with a spring and a diamond tip, where the spring is connected to a support block and an adjustment device, allowing for a defined and reproducible force application to the glass surface, ensuring consistent geometry of the scratching tip and preventing tilting of the diamond during testing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional scratch testing methods are used on glass surfaces, then the high surface hardness of glass can be tested, but the application of force becomes difficult to control consistently, leading to variable measurement results

Engineering Contradiction:
Improvemeasurement resultsVSAvoidapplication of force
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces manual mechanical force application with a spring-based mechanical system that automatically applies and maintains constant force. The spring mechanism substitutes for manual control, providing consistent force application throughout the scratching process, which resolves the contradiction between measurement precision and ease of operation.

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

Solution Approach 2:

The spring mechanism is self-regulating and automatically maintains the required force level during the scratching process without external intervention. The spring's elastic properties enable it to self-adjust and maintain constant force application, eliminating the need for complex external control systems and improving both precision and operational ease.

Inventive Principle:
Principle #25Self-service

2Ease of manufacture

If force is applied to scratch glass surfaces, then scratching can be performed, but microcracks and hairline cracks are formed that affect the stability and strength of the glass

Engineering Contradiction:
Improvescratching processVSAvoidstability and strength of glass
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent carefully controls and changes the parameters of force application, including magnitude, distribution, and duration. By optimizing these parameters through the spring mechanism, the system achieves effective scratching while minimizing the formation of microcracks and hairline cracks, thus improving both the ease of manufacturing and the reliability of the glass structure.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The spring mechanism provides beforehand cushioning by gradually applying and maintaining controlled force during the scratching process. This cushioning effect prevents sudden force spikes that could cause microcracks, while still achieving the necessary scratching effect, thereby improving both manufacturing ease and structural reliability.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Measurement precision

If the scratching tip geometry is maintained over many tests, then reproducible results can be obtained, but the tip geometry changes due to wear and deformation

Engineering Contradiction:
Improvereproducible resultsVSAvoidtip geometry stability
Core Design Contradiction:
Measurement precisionVSDuration of action of stationary object

Solution Approach 1:

The patent employs a dynamic spring mechanism that adapts to wear and maintains consistent force application throughout the testing process. The spring's elasticity allows it to compensate for tip geometry changes over time, ensuring that reproducible results are obtained even as the scratching tip undergoes wear, thus resolving the contradiction between measurement precision and duration of action.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The spring mechanism provides implicit feedback by automatically adjusting force application based on the changing conditions of the scratching tip and glass surface. This feedback mechanism ensures that consistent force is maintained throughout the test, compensating for tip wear and maintaining reproducible results over an extended duration of action.

Inventive Principle:
Principle #23Feedback

4Ease of operation

If simple testing equipment is used, then the test can be performed easily, but the ability to apply constant force and maintain tip geometry is insufficient

Engineering Contradiction:
Improvetest performanceVSAvoidconstant force application
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent replaces complex mechanical force control systems with a simple spring-based mechanism that inherently provides constant force application. This substitution maintains ease of operation while achieving the necessary manufacturing precision through the spring's elastic properties, which automatically regulate force without requiring complex external control systems.

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

Solution Approach 2:

The spring mechanism is self-regulating and automatically maintains constant force application throughout the testing process without requiring complex external control systems. This self-service capability allows simple equipment to achieve precise force application, resolving the contradiction between ease of operation and manufacturing precision.

Inventive Principle:
Principle #25Self-service

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 precise and reproducible scratching of glass surfaces, reducing the risk of microcracks and providing reliable measurement results, suitable for testing various types of glass panes, including vehicle windshields, without the need for elaborate equipment.

Implementation Method 1

The spring is connected within the scratch cylinder to a support block and a diamond attached to the support block

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2679979B1Scratch tester for glass panes
Publication Date: 2019.11.06 SAINT GOBAIN VITRAGE SA
  • EP2679979B1 patent drawingFigure 1
  • EP2679979B1 patent drawingFigure 2
  • EP2679979B1 patent drawingFigure 3

AI summary

The tester has a scratching cylinder (1) comprising a spring (5) supported in an inner side of the cylinder. The spring is connected with a holding block (9) and diamonds (10) that are fastened to the holding block. An adjusting device (7) is connected with the spring in a detachable or fixed manner in an inner side of an adjusting window (6) along an outer surface of the cylinder. A sliding block (2) has a bore (16) and sliding rails (3) that are arranged below the sliding block, where the cylinder is fixed in an inner side of the bore by using a locking screw (4). An independent claim is also included for a method for defined scratching of a glass pane.