Pin-Shaped Roughness Probe for Inner Corner Measurement

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Solution Overview

Problem

Existing surface roughness measuring devices are unable to accurately measure roughness in narrow depressions, inner corners, or inner corner radii of workpieces due to their spatial extent and design limitations, which restricts their application to standard measurements and fails to provide precise data on surface microstructure profiles.

Innovation Solution

A compact, pin-like or conically shaped measuring device with a movably mounted wand and integrated sensors for translational and rotational movement, allowing precise contact with the surface and enabling measurements in hard-to-reach areas by using a skid and protective cap for guidance and protection, along with sensors for contact pressure and inclination control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional roughness measuring device with horizontal probe arm is used, then standard surface roughness measurements can be performed, but measurements in narrow depressions, inner corners, or hard-to-reach areas become impossible or difficult

Engineering Contradiction:
Improvemeasurement location accessibilityVSAvoidspatial expansion of feed unit and probe
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The probe arm is reoriented from horizontal (parallel to workpiece surface) to vertical (perpendicular to workpiece surface), allowing the probe tip to reach into narrow depressions and inner corners that are inaccessible to conventional horizontal-probe devices. This dimensional change enables measurement in previously unreachable locations without requiring complex spatial expansion of the feed unit.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If the probe arm is positioned horizontally parallel to the workpiece surface, then the measuring system can be simplified, but it becomes impossible to measure surfaces in depressions or on workpiece edges

Engineering Contradiction:
Improvemeasurement capability in challenging locationsVSAvoidspatial extent of feed unit and probe
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

By positioning the probe arm vertically perpendicular to the workpiece surface instead of horizontally parallel to it, the device achieves access to challenging measurement locations such as inner corners and depressed areas. This reorientation eliminates the need for complex spatially extensive feed units while maintaining ease of operation in hard-to-reach areas.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If a hand-held testing device with spring element is used, then the test force can be limited to protect the test surface, but the measurement accuracy and standard compliance are compromised

Engineering Contradiction:
Improvesurface roughness measurement accuracyVSAvoidstructural design for force control
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The spring element force control mechanism is replaced with an electronically controlled force application system that uses sensors and feedback control to maintain precise, standardized contact force. This substitution eliminates the compromise between force limitation and measurement accuracy, enabling both protective force control and standard-compliant precise measurements.

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

Solution Approach 2:

A feedback control system continuously monitors the contact force between probe tip and workpiece surface, adjusting the applied force to maintain the standardized 0.75 N contact force required for accurate roughness measurements. This feedback mechanism ensures both surface protection and measurement precision without requiring complex mechanical force limitation structures.

Inventive Principle:
Principle #23Feedback

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 reliable and standard-compliant measurements of surface roughness in challenging locations, such as narrow blind holes and inner corners, with improved handling and expanded application possibilities by ensuring constant contact pressure and minimizing distortion.

Implementation Method 1

The deflection induced by the workpiece surface via the probe tip is measured by a measuring system, usually inductive

Methodology Applied
Scientific EffectMechanical displacement detection: Displacement

Implementation Method 2

A spring element is arranged between the holding pen and the probe tip, which is elastic in at least one spatial direction

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2631592B1Measuring device and method for measuring the roughness of the surface of a body
Publication Date: 2014.07.16 BREITMEIER MESSTECHN
  • EP2631592B1 patent drawingFigure 1
  • EP2631592B1 patent drawingFigure 2~3
  • EP2631592B1 patent drawingFigure 4

AI summary

The measurement device (10.1) has a pin-like housing (13.1) extending in the direction of its longitudinal axis (15) over a housing length (21). A measuring system (30) is provided in the housing for detection of a contact body (25) in a measuring direction (26). A bearing (24.1) or mounting suspension is fixed to the housing for a contact body (25). The contact body is movably placed at the bearing or at the mounting suspension relative to the housing in the measuring direction, and has a contacting end (27) for determination of the surface profile or roughness of the surface (11). An independent claim is included for a method for measuring a surface profile or roughness of a surface of a body by a measurement device.