Tool Measurement Optics With Flow-Activated Check Valve Sealing

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Solution Overview

Problem

Existing tool measurement apparatuses in machine tools are vulnerable to contamination from cutting debris and coolant fluid, particularly when air supply is interrupted, leading to potential damage and degradation of optical components.

Innovation Solution

Incorporation of a check valve, such as a duckbill valve, in the optical path of the tool measurement apparatus to provide protection against contaminants, which opens with a gas flow and closes in the absence of gas flow, combined with a gas expulsion aperture and optional shutter assembly for additional protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a pneumatically activated shutter seal is used to protect optical components, then protection against contaminants is improved, but device complexity increases and moving parts wear over time

Engineering Contradiction:
Improveprotection against contaminantsVSAvoidmoving parts and seals
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the vulnerable moving parts (shutter mechanism) from the optical path protection system and replaces them with a static check valve that has no moving components. The check valve is integrated into the gas expulsion aperture structure, eliminating the need for separate actuators, springs, and seals while maintaining protection functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The check valve is designed to automatically open and close based on gas flow direction without requiring external control systems. Gas flow in one direction opens the valve to allow expulsion, while reverse flow or absence of flow automatically closes it to prevent contaminant ingress, making the system self-regulating and eliminating complex control mechanisms.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If air is expelled through angled apertures to protect optical components, then measurement accuracy is improved, but protection is only effective when air supply is active

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidprotection continuity
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The check valve acts as an intermediary element between the optical components and the external environment. It selectively permits gas flow in the forward direction to maintain measurement accuracy while blocking reverse flow or preventing contaminant ingress when air supply is interrupted, thus bridging the gap between measurement requirements and protection needs.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The check valve is positioned upstream in the gas flow path to preemptively block contaminants before they can reach the optical components. By placing the valve at the aperture entrance rather than downstream, it prevents contaminant accumulation in the air channels before the air supply is restored, eliminating the need for post-contamination cleaning.

Inventive Principle:
Principle #9Preliminary anti-action

3Device complexity

If contaminants are allowed to enter air channels, then device simplicity is improved, but component degradation and damage occur

Engineering Contradiction:
Improveprotection structureVSAvoidcontaminant ingress
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The check valve utilizes the natural pressure differential created by gas flow to its advantage. During normal operation, forward gas flow opens the valve to maintain measurement functionality. When gas flow stops or reverses, the pressure differential automatically closes the valve, converting what would be a harmful condition (stopped flow) into a protective state that blocks contaminants without requiring additional energy or control systems.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

The solution effectively prevents ingress of contaminants, even when gas supply is off, maintaining the integrity of optical components and reducing the need for frequent disassembly and cleaning, while allowing for a compact design.

Implementation Method 1

a check valve located in the optical path and the bleed gas is supplied to the gas expulsion aperture through the check valve, characterised in that the flow of the bleed gas through the check valve causes the check valve to adopt an open configuration defining a passageway through which the light beam can pass

Methodology Applied
Scientific EffectCheck valve flow control: Valve

Implementation Method 2

a protection device including a gas expulsion aperture configured to expel a bleed gas supplied from an external gas source, the optical path also passing through the gas expulsion aperture

Methodology Applied
Scientific EffectGas flow expulsion: Jet

Data Source

PatentEP4433257B1Tool measurement apparatus for a machine tool
Publication Date: 2025.12.31 RENISHAW PLC
  • EP4433257B1 patent drawingFigure 1
  • EP4433257B1 patent drawingFigure 2
  • EP4433257B1 patent drawingFigure 3~4

AI summary

A tool measurement apparatus for a machine tool includes a transmitter portion (100) including a light source (102) for generating a light beam (104) and a receiver portion (300) including a detector for detecting the light beam (104), the light beam being passed from the light source to the detector along an optical path. At least one of the receiver portion (300) and the transmitter portion (100) comprises a protection device including a gas expulsion aperture (108) configured to expel a bleed gas supplied from an external gas source. The optical path also passes through the gas expulsion aperture (108). The protection device further comprises a check valve (112; 200) located in the optical path. The bleed gas is supplied to the gas expulsion aperture (108) through the check valve (112; 200) and the flow of the bleed gas through the check valve (112; 200) causes the check valve to adopt an open configuration defining a passageway through which the light beam (104) can pass.