Cone Mirror Alignment for Inner Diameter Measurement

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Solution Overview

Problem

Existing non-contact inner diameter measuring devices for cylindrical members face challenges in aligning the center line of the cone mirror with the optical axis of the laser beam, lacking a reliable method for precise alignment.

Innovation Solution

The inner diameter measuring device incorporates a centering unit with an adjusting mechanism, including X-axis and Y-axis sliders and pulling/pushing bolts, to align the cone mirror's center line with the optical axis, ensuring accurate projection and measurement of the inner diameter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a cone mirror is used to project the laser beam in the total circumferential direction, then the laser beam can be reflected uniformly around the cylindrical member, but it becomes difficult to align the center line of the cone mirror with the optical axis of the laser beam

Engineering Contradiction:
Improvealignment precision between cone mirror center line and laser beam optical axisVSAvoidcomplexity of alignment mechanism
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-aligning the cone mirror's center line with the laser beam optical axis during the assembly process. The alignment mechanism allows adjustment before final fixation, ensuring that the center line of the cone mirror coincides with the optical axis of the laser beam without requiring complex real-time alignment during operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary alignment mechanism that serves as a mediator between the cone mirror and the laser beam source. This mechanism includes adjustment components that facilitate the alignment process by providing a controlled interface for positioning the cone mirror relative to the optical axis, thereby simplifying the overall alignment task.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If high precision parts are used to ensure accurate alignment, then measurement accuracy improves, but manufacturing costs increase

Engineering Contradiction:
Improveinner diameter measurement accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces the need for high-precision mechanical parts with a mechanical adjustment mechanism. Instead of relying on precisely manufactured fixed components, the invention uses adjustable mechanisms that allow alignment to be achieved through positioning and locking, thereby reducing manufacturing costs while maintaining measurement precision.

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

3Manufacturing precision

If the cone mirror is fixed in position, then the device structure is simplified, but alignment accuracy cannot be ensured

Engineering Contradiction:
Improvealignment accuracyVSAvoidstructure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies dynamics by transitioning from a static fixed structure to a dynamic adjustable structure. The cone mirror is initially positioned using adjustment mechanisms to achieve accurate alignment, then locked in place. This allows the system to be adjusted during assembly or maintenance while maintaining stability during operation, balancing alignment accuracy with structural simplicity.

Inventive Principle:
Principle #15Dynamics

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 enables precise alignment of the laser beam, allowing for reliable measurement of the inner diameter and shape of cylindrical members, improving measurement accuracy and reducing manufacturing costs by eliminating the need for high precision parts.

Implementation Method 1

a cone mirror having a conical reflection surface is used as means for projecting a laser beam in a total circumferential direction, and the laser beam is reflected in a total circumferential direction

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

an image of the optical ring is picked up, and a shape and a diameter of the optical ring are measured from the image

Methodology Applied
Scientific EffectImage pickup: Photography

Data Source

PatentEP2813805B1Inside-diameter measurement device
Publication Date: 2019.12.04 IHI CORP
  • EP2813805B1 patent drawingFigure 1
  • EP2813805B1 patent drawingFigure 2
  • EP2813805B1 patent drawingFigure 3

AI summary

An inner diameter measuring device, comprising an image pickup unit (2) provided at a base end of a frame unit (6) and for picking up an image of a forward end side, a centering unit (4) provided at a forward end of the frame unit, a laser beam diffusing unit (5) provided on the centering unit and at a forward end side of the centering unit via a light transmitting window, a laser beam emitting unit (3) provided on a base end side of the centering unit, and a cone mirror (51) provided on the laser beam diffusing unit and having a conical reflection surface at a forward end, wherein a center line of the cone mirror coincides with an optical axis of the image pickup unit, and the centering unit is adapted to adjust a posture of the image pickup unit so that a laser beam (17) projected from the laser beam emitting unit enters a vertex of the cone mirror.