Dimension Measuring Instrument With Direct Force Sensor

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Solution Overview

Problem

Existing dimension measuring instruments, such as vertical measuring columns and coordinate measuring machines, face limitations in precision and flexibility due to reliance on indirect force measurement methods, which are prone to errors and require complex adjustments for different orientations, limiting their application to rigid materials and specific surface orientations.

Innovation Solution

A dimension measuring instrument that directly converts contact force into an electrical signal using a prestressed force sensor, combined with additional elastic connections and friction elements, allowing precise control and adaptation of contact force across various orientations without influencing position measurement, enabling finer measurement and correction of dimensional values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If indirect force measurement methods are used, then the device structure can be simpler, but measurement precision deteriorates due to errors in force measurement

Engineering Contradiction:

Improvedevice structureVSAvoidmeasurement precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces indirect mechanical force measurement methods with a direct force sensor system that converts contact force into an electrical signal. This substitution eliminates the errors associated with indirect measurement while maintaining relatively simple device structure through the use of integrated sensor technology.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If elastic transmission elements are used to transmit measurement force, then the system can accommodate force variations, but the floating carriage introduces additional degree of freedom that influences measurement precision

Engineering Contradiction:

Improveforce variation accommodationVSAvoidmeasurement precision

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent extracts and eliminates the floating carriage mechanism from the system, removing the additional degree of freedom that compromised measurement precision. The force transmission is simplified to a direct path from the measurement tip through the force sensor, maintaining force variation accommodation while improving precision.

Inventive Principle:

Principle #2Taking out (Extraction)

3Ease of manufacture

If displacement sensors are used to measure elastic element deformation, then the device can be less expensive, but the sensors exhibit defects including imprecise referenced information and calibration deterioration

Engineering Contradiction:

Improvedevice costVSAvoidmeasurement precision

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent replaces displacement sensors with a direct force sensing system that measures contact force directly rather than indirectly through elastic element deformation. This substitution provides more precise and stable measurements while remaining cost-effective through the use of integrated sensor technology.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Device complexity

If the measuring instrument is designed for rigid materials with zero deformation, then the measurement system can be simpler, but the field of application is limited

Engineering Contradiction:

Improvemeasurement system complexityVSAvoidfield of application

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent changes the fundamental parameter of the measurement system from assuming zero deformation to actively measuring and compensating for elastic deformation through direct force sensing. This enables the instrument to accurately measure soft and compliant materials while maintaining relatively simple system architecture through the use of direct force measurement.

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 measurement precision, reduces error sources, and allows for flexible operation across different orientations, providing accurate dimensional measurements by directly controlling and adapting to contact force variations, thus overcoming the limitations of existing technologies.

Implementation Method 1

a force sensor (100) for measurement along the axis of movement and measurement of the instrument

Methodology Applied

Scientific EffectPiezoresistive effect: Piezoresistive Effect

Implementation Method 2

at least one elastic element (120) interposed on either side between the cable (50) and the carriage (40)

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentEP2251634B1Dimension measuring instrument consisting in a vertical measurement column

Publication Date: 2018.11.28 TESA SA(CH)

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AI summary

The instrument has a frame supporting a reference position defining a measuring axis, and a carriage moving parallel to the frame. A driving device is linked to the carriage by a transmission to determine linear displacement of the carriage, and a feeler is attached to the carriage and contacts with a piece to be measured. A position transducer is arranged on the carriage to supply a measurement of the feeler's position relative to the axis. The carriage is connected to the device via a force sensor (100) e.g. strain gauge, measuring contact force exerted by a probe (59) on the piece.