Surface Texture Measuring Instrument with Internal Displacement Detector

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Solution Overview

Problem

Existing surface texture measuring instruments face issues with accuracy due to offset detectors, risk of damage to measurement arms and styluses, poor usability, and operational inefficiency, especially when exchanging measurement arms with different weights.

Innovation Solution

A surface texture measuring instrument with a measurement arm supported in circular movement, a stylus, and a displacement detector housed in a casing, featuring an attachment-detachment mechanism within the casing to reduce errors and prevent damage, along with a balance adjuster using a voice coil to automatically adjust the measurement arm's balance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the detector is disposed outside the housing to enable easy exchange of the measurement arm, then the ease of operation is improved, but the measurement precision deteriorates due to offset error between the detector and the measurement arm axis

Engineering Contradiction:
Improveease of measurement arm exchangeVSAvoidmeasurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent merges the detector with the housing structure, integrating it inside the housing rather than disposing it outside. This integration ensures the detector is precisely positioned on the rotation axis of the measurement arm, eliminating offset errors while still allowing easy exchange of the measurement arm through the opening in the housing.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of operation

If the connecting unit is disposed outside the housing to enable detachable measurement arm exchange, then the ease of operation is improved, but the reliability deteriorates as the measurement arm may fall when external force acts on it

Engineering Contradiction:
Improveease of measurement arm exchangeVSAvoidstability of measurement arm attachment
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent merges the connecting unit with the housing by disposing it inside the housing. This integration provides structural support and protection for the measurement arm attachment mechanism, preventing the measurement arm from falling when external force acts on it, while still allowing easy detachable exchange through the opening in the housing.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If the connecting unit is disposed outside the housing to enable measurement arm exchange, then the ease of operation is improved, but the object-affected harmful factors worsen as the connecting unit may interfere with the object and become dirty

Engineering Contradiction:
Improveease of measurement arm exchangeVSAvoidcontamination and interference
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent merges the connecting unit with the housing by integrating it inside the housing. This protects the connecting unit from external contamination and prevents it from interfering with the object being measured, while still allowing easy exchange of the measurement arm through the opening in the housing.

Inventive Principle:
Principle #5Merging (Combining)

4Adaptability or versatility

If the measurement arm is made detachable to enable exchange of styluses with different profiles, then the adaptability is improved, but the device complexity increases due to additional attachment and detachment mechanisms

Engineering Contradiction:
Improveability to measure different surface profilesVSAvoidcomplexity of attachment mechanism
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the measurement arm into a detachable component that can be easily exchanged. This segmentation allows different styluses with various profiles to be attached and detached as needed, providing adaptability for measuring different surface profiles while keeping the attachment mechanism relatively simple.

Inventive Principle:
Principle #1Segmentation

5Adaptability or versatility

If the measurement arm weight is changed to match different measurement requirements, then the adaptability is improved, but the device complexity increases due to need for balance adjustment

Engineering Contradiction:
Improveadaptability to different measurement forcesVSAvoidcomplexity of balance adjustment
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent incorporates a balance adjustment mechanism that acts as a counterweight system. When the measurement arm weight is changed to match different measurement requirements, the balance adjustment mechanism compensates for the weight difference, maintaining proper balance without requiring complex redesign of the entire system.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

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 configuration enhances measurement accuracy, reduces the risk of damage, improves usability, and operational efficiency by ensuring proper attachment and balance adjustment during arm exchanges.

Implementation Method 1

a balance adjuster that adjusts balance of the measurement arm by adjusting an electromagnetic force generated by a voice coil

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentEP2515069B1Surface texture measuring instrument
Publication Date: 2016.03.16 MITUTOYO CORP
  • EP2515069B1 patent drawingFigure 1
  • EP2515069B1 patent drawingFigure 2
  • EP2515069B1 patent drawingFigure 3

AI summary

In a surface texture measuring instrument, a measurement arm (24) includes: a first measurement arm (24A) that is supported by a bracket (22) around a support shaft (23) movably in a circular movement in a casing (28); and a second measurement arm (24B) having styluses (26A, 26B) that are attachably and detachably provided to an end of the first measurement arm (24A) via an attachment-detachment mechanism (25), the attachment-detachment mechanism (25) being arranged in the casing. A displacement detector (27) includes: a scale (27A) provided to the measurement arm; and a detection head provided to the bracket (22) to face the scale. A detecting surface of the scale is on an axis of the measurement arm and on a plane of the circular movement of the measurement arm.