Notched Spherical Touch Probe for Narrow Surface Measurement

Solution Overview

Problem

Existing touch probes with spherical contactors struggle to accurately measure narrow surfaces due to interference issues when the contactor diameter exceeds the width of the measurement area.

Innovation Solution

A touch probe with a spherical contactor featuring a notched part that includes an abutment part, allowing precise contact with narrow surfaces without interference by adjusting the contact point to the measurement direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a spherical contactor is used for measurement, then the contactor structure is simple and easy to manufacture, but it cannot accurately measure narrow surfaces because the contactor diameter exceeds the width of the measurement area causing interference

Engineering Contradiction:

Improvecontactor structure simplicityVSAvoidmeasurement accuracy on narrow surfaces

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The spherical contactor is segmented by introducing a notch that divides the sphere into distinct regions. The abutment part (equatorial region) is separated from the polar regions, allowing the equatorial line to contact narrow surfaces while the polar regions are retracted and cannot cause interference. This segmentation enables the contactor to measure narrow surfaces accurately while maintaining the simple spherical structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The harmful portions (polar regions) are extracted or removed from the measurement process by creating a notch that prevents them from contacting the workpiece. Only the necessary equatorial region (abutment part) remains active for measurement, eliminating interference from other parts of the spherical contactor.

Inventive Principle:

Principle #2Taking out (Extraction)

2Strength

If a spherical contactor with large diameter is used, then the contactor is robust and easy to manufacture, but it cannot contact portions narrower than its diameter without interference from other parts

Engineering Contradiction:

Improvecontactor robustnessVSAvoidability to measure narrow surfaces

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The spherical contactor is segmented by introducing a notch that divides the sphere into distinct regions. The abutment part (equatorial region) is separated from the polar regions, allowing the equatorial line to contact narrow surfaces while the polar regions are retracted and cannot cause interference. This segmentation enables the contactor to measure narrow surfaces accurately while maintaining the simple spherical structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the spherical contactor are given different functional qualities. The equatorial region (abutment part) is designed for contact with workpiece surfaces, while the polar regions are designed to be retracted and non-contacting. This local differentiation allows the contactor to adapt to various surface widths while maintaining overall structural robustness.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If the contactor diameter is increased for robustness, then manufacturing is easier, but measurement of narrow surfaces becomes impossible due to interference

Engineering Contradiction:

Improvecontactor manufacturing simplicityVSAvoidmeasurement precision on narrow features

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The spherical contactor is segmented by introducing a notch that divides the sphere into distinct regions. The abutment part (equatorial region) is separated from the polar regions, allowing the equatorial line to contact narrow surfaces while the polar regions are retracted and cannot cause interference. This segmentation enables the contactor to measure narrow surfaces accurately while maintaining the simple spherical structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The notch introduces asymmetry into the otherwise symmetric spherical contactor. The notch is positioned to create a specific abutment part geometry that enables contact with narrow surfaces, breaking the rotational symmetry but maintaining functional effectiveness for measurement purposes.

Inventive Principle:

Principle #4Asymmetry

Data Source

PatentEP4653803A1Touch probe

Publication Date: 2025.11.26 MAKINO MILLING MASCH CO LTD

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AI summary

A touch probe (10), mounted on a measuring device (100), for measuring a dimension of a measurement object by moving relative to the measurement object (W) in a measuring direction (A1, A2, A3), and being brought into contact with the measurement object, is provided with a main body portion (12) mounted on the measuring device, a support shaft (14) provided on the main body portion, and a contact (20) having a spherical outer shape, provided at a tip end of the support shaft, wherein the contact (20) includes a contacting portion (24) which is formed by means of a notched part (22) and which projects in the measuring direction.