Optical Protection Conduit Geometry for Stable Tool Measurement

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Solution Overview

Problem

Existing optical measurement devices, such as non-contact tool measurement devices, face issues with air turbulence that degrade measurement repeatability despite efforts to reduce it, as contaminants like coolant and cutting debris continue to affect the free-space optical path.

Innovation Solution

The device incorporates a protection member with a conduit that has a varying cross-sectional profile along the airflow axis, allowing light to pass through the optical axis while expelling air along an angled airflow axis, thereby reducing turbulence and the volume of air needed for protection, using a design that minimizes burrs and sharp edges to enhance airflow smoothness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If air is expelled through a conduit with invariant cross-sectional profile (e.g., drilled hole), then the device structure is simple, but air turbulence in the free-space optical path increases

Engineering Contradiction:
Improveconduit structureVSAvoidmeasurement repeatability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies parameter changes by varying the cross-sectional profile of the conduit along its length. The conduit transitions from a larger cross-sectional area at the inlet to a smaller cross-sectional area at the outlet, creating a tapered geometry that reduces air turbulence. This gradual area reduction allows the air stream to expand smoothly into the external environment, minimizing turbulence in the free-space optical path while maintaining measurement repeatability.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If air is expelled along the optical axis, then the protection against contaminants is effective, but air turbulence along the free-space beam path increases

Engineering Contradiction:
Improvecontaminant protectionVSAvoidmeasurement repeatability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies asymmetry by angling the airflow axis relative to the optical axis. The conduit is positioned and oriented such that the expelled air stream is directed at an angle to the optical path, creating an asymmetric arrangement. This angular offset allows the air to effectively protect the optical components from contaminants while preventing turbulence from directly interfering with the light beam propagation.

Inventive Principle:
Principle #4Asymmetry

3Object-affected harmful factors

If more air is expelled to improve contaminant protection, then protection effectiveness increases, but air consumption increases

Engineering Contradiction:
Improvecontaminant protectionVSAvoidair consumption
Core Design Contradiction:
Object-affected harmful factorsVSLoss of substance

Solution Approach 1:

The varying cross-sectional profile of the conduit optimizes airflow characteristics, creating a more efficient air stream that provides effective contaminant protection with reduced air consumption. The tapered geometry enhances the coherence and directionality of the air stream, allowing for lower flow rates to achieve the same protective effect, thereby reducing air consumption while maintaining protection effectiveness.

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 design significantly reduces air turbulence in the free-space beam path, improving measurement repeatability and reducing air consumption while maintaining optical performance, allowing for stable airflow that minimizes interference with the light beam.

Implementation Method 1

a stream of air is guided out of the conduit along an airflow axis

Methodology Applied
Scientific EffectAir flow:

Implementation Method 2

a beam of light is passed through the conduit along an optical axis

Methodology Applied
Scientific EffectLight transmission:

Data Source

PatentEP4127603B1Measuring device
Publication Date: 2024.11.20 RENISHAW PLC
  • EP4127603B1 patent drawingFigure 1~2
  • EP4127603B1 patent drawingFigure 3~4
  • EP4127603B1 patent drawingFigure 5~6

AI summary

A protection member (126) for an optical measurement device, such as a break- beam tool setting device (2) for a machine tool, is described. The protection member (126) comprises a conduit (140) through which light and air can pass. The conduit (140) is configured such that, in use, a beam of light is passed through the conduit along (140) an optical axis (O) and a stream of air is guided out of the conduit along an airflow axis (A). The optical axis (O) is non-parallel to the airflow axis (A) and the conduit (140) has a varying cross-sectional profile along the airflow axis (A). Improved measurement repeatability is provided.