Non-contact Laser Measurement of Circular Member Inner Circumference
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Solution Overview
Problem
Existing methods for measuring the inner circumferential length of circular members, such as bead and cylindrical rubber members, often result in deformation due to applied loads, compromising measurement accuracy.
Innovation Solution
A non-contact inner circumferential length measuring method using a two-dimensional sensor that measures the separation distance from the inner surface of the circular member without applying external forces, allowing the member to be placed flat on a support with projection portions that minimize deformation and ensure accurate positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a roller or measurement support is brought into contact with the inner circumferential surface of the circular member, then the member can be positioned and measured, but the contact applies force that deforms the member and reduces measurement accuracy
Solution Approach 1:
The patent replaces the mechanical contact-based measurement system (rollers or measurement supports that physically touch the circular member) with a non-contact optical measurement system using a laser displacement sensor. The sensor measures the inner circumferential length by detecting the position of the inner circumferential surface without applying any mechanical force, thereby eliminating deformation caused by contact forces while maintaining measurement capability.
2Measurement precision
If a cylindrical measurement support is used to measure inner circumferential length, then measurement can be performed, but the support applies expanding force that deforms the circular member
Solution Approach 1:
The patent eliminates the cylindrical measurement support that applies expanding force by substituting it with a non-contact laser displacement sensor. The sensor system measures the inner circumferential length by optically detecting the position of the inner circumferential surface at multiple points, completely avoiding the application of mechanical expanding forces that would deform the circular member and compromise measurement accuracy.
3Ease of operation
If direct contact measurement is used, then the measurement process is simple, but deformation occurs reducing accuracy
Solution Approach 1:
The patent replaces the simple but harmful direct contact measurement method with a non-contact laser displacement sensor system. Although the sensor system is more complex than a simple roller, it maintains ease of operation through automated measurement while dramatically improving precision by eliminating deformation. The sensor can quickly measure multiple points around the circumference without manual intervention, achieving both simplicity and accuracy.
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 accurate measurement of the inner circumferential length without deforming the circular member, allowing for precise determination of the inner diameter and reducing unnecessary external forces, thus enhancing measurement accuracy and versatility for various sizes.
Implementation Method 1
a laser displacement sensor which measures a separation distance to the inner circumferential surface in a non-contact state
Data Source
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AI summary
Provided is an inner circumferential length measuring device for a circular member capable of accurately measuring an inner circumferential length without applying an unnecessary load of the circular member. By placing a circular member (12) on a support (4) by engaging an inner circumferential surface (12a) of the circular member (12) with two projection portions (7) projecting from a surface of the support (4) in an upright state, then lowering the support (4) to a horizontal state and placing the circular member (12) flat in an unrestrained state on the support (4), disposing a two-dimensional sensor (8) facing the inner circumferential surface (12a) of the circular member (12) at a predetermined measurement position, rotating the two-dimensional sensor (8) about rotation shaft (9) at a predetermined position inward of the circular member (12), and measuring a separation distance (d) from the two-dimensional sensor (8) to the inner circumferential surface (12a) around an entire circumference of the circular member (12); an inner circumferential length (L) of the circular member (12) is calculated via a calculation unit (11) using the separation distance (d) measured and a distance (w) from the rotation shaft (9) to the two-dimensional sensor (8) in a plan view.