Circularity Measuring Apparatus Dynamic Stylus Inclination Control

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Solution Overview

Problem

Existing circularity measuring apparatuses face issues with stylus breakage when measuring objects with notches or inner surfaces, requiring program suspension and manual stroke setting due to stylus inclination and potential contact with edges or bore peripheries.

Innovation Solution

A circularity measuring apparatus with a contact-type stylus held by a holder allowing adjustable inclination, equipped with a displacement detector and controller to estimate stylus position and set optimal stroke ranges, preventing stylus breakage by dynamically adjusting the stroke based on detected inclination angles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the stylus is positioned with an inclination to avoid contact with the holder, then the holder diameter can be larger than the stylus, but the top end of the stylus may be caught by the outer periphery of the bore causing breakage

Engineering Contradiction:
Improveholder diameterVSAvoidstylus integrity
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The holder is designed to dynamically change the inclination angle of the stylus during measurement. The inclination angle adjusting mechanism allows the holder to automatically adjust the stylus orientation based on real-time feedback from the displacement detector, enabling the stylus to navigate around bore peripheries without breakage while maintaining a larger holder diameter for stability

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

A displacement detector is integrated to detect the displacement amount of the stylus top end in real-time. This feedback information is fed to the controller which then adjusts the inclination angle of the holder accordingly, creating a closed-loop control system that prevents stylus breakage by anticipating and avoiding contact with bore edges

Inventive Principle:
Principle #23Feedback

2Reliability

If the measuring program is suspended to fix the stylus position before passing through notched portions, then stylus breakage is prevented, but measurement efficiency is reduced due to program suspension and manual intervention

Engineering Contradiction:
Improvestylus protectionVSAvoidmeasurement efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system performs self-protection by automatically detecting when the stylus approaches a notched portion through displacement detection, and autonomously adjusting the inclination angle to avoid breakage. This eliminates the need for program suspension and manual intervention, maintaining both stylus safety and measurement continuity

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The displacement detector anticipates potential stylus breakage by detecting displacement trends before the stylus actually contacts the notch edge. The controller uses this preliminary information to proactively adjust the inclination angle, preventing breakage before it occurs and avoiding the need for program interruption

Inventive Principle:
Principle #10Preliminary action

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

Enables continuous measurement without program suspension, maintaining stylus integrity by dynamically adjusting the stroke range during measurements of notched objects or inner surfaces, eliminating the need for manual settings and additional stylus position grasping means.

Implementation Method 1

Displacement of the arm is detected through measuring an elastic deformation of the spring caused by the contact pressure exerted to the stylus being pressed against the surface to be measured

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2261595B1Circularity measuring apparatus
Publication Date: 2012.10.31 MITUTOYO CORP
  • EP2261595B1 patent drawingFigure 1~2
  • EP2261595B1 patent drawingFigure 3
  • EP2261595B1 patent drawingFigure 4A~4E

AI summary

A circularity measuring apparatus includes: a rotary table on which a measured object is loaded; a contact-type stylus configured to contact a substantially circular measured surface of the measured object with an inclination; a holder configured to hold the stylus within a predetermined stroke range so that an inclination angle of the stylus is changeable; a displacement detector configured to detect a displacement of the inclination angle of the stylus, which is caused due to a contact between the stylus and the measured surface; and a controller configured to: estimate a position of a top end of the stylus based on an output of the displacement detector; and instruct the holder in an optimal stroke range in the position.