Decoupled Ultrasonic Test Head for Hollow Shaft Scanning

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Solution Overview

Problem

Existing ultrasonic testing devices for hollow shafts, particularly those of wheelsets, are bulky, complex, and difficult to transport and handle, leading to challenges in ensuring accurate and efficient material inspection for safety.

Innovation Solution

A compact, modular device design comprising a base body, adapter, and test lance with an ultrasonic probe that is axially and rotationally adjustable, featuring centering means and radial decoupling mechanisms to maintain precise contact with the shaft's inner surface during testing, allowing for easy handling and efficient scanning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a stationary ultrasonic testing device is used, then measurement precision is improved, but device complexity and weight increase significantly

Engineering Contradiction:
Improveultrasonic testing accuracyVSAvoiddevice structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The device is divided into three main segments: base body, adapter, and test lance. The test lance can be detached from the adapter, allowing the base body to remain stationary while the test lance is inserted into the hollow shaft. This segmentation enables the complex testing function to be separated from the heavy base structure, reducing overall device complexity while maintaining measurement precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a fully stationary three-dimensional testing system to a system where the test lance can be inserted axially into the hollow shaft. This dimensional change allows the probe to access the inner surface of the shaft while the base body remains outside, simplifying the overall device structure and reducing weight.

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

2Adaptability or versatility

If the test lance is made longer to match hollow shaft length, then adaptability is improved, but radial deflection and measurement precision deteriorate

Engineering Contradiction:
Improvecompatibility with hollow shaft lengthsVSAvoidcontact pressure stability
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

A cardan coupling is introduced as an intermediary element between the test lance and the ultrasonic probe. This cardan coupling decouples the rotational movement of the test lance from the probe, allowing the probe to maintain stable radial contact with the hollow shaft inner surface even when the test lance experiences radial deflection due to its length. The cardan coupling acts as a mediator that transfers rotational motion while blocking radial movements from affecting the probe.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The rigid mechanical connection between the test lance and probe is replaced with a cardan coupling mechanism that allows rotational movement while isolating radial deflections. This substitution of the mechanical connection system enables the test lance to be made longer for better adaptability without compromising the contact stability required for precise measurements.

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

3Ease of operation

If the ultrasonic probe is rigidly fixed to the test lance, then ease of operation is improved, but measurement precision deteriorates due to transmitted radial deflections

Engineering Contradiction:
Improveprobe stabilityVSAvoidcontact pressure consistency
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The cardan coupling serves as an intermediary between the test lance and the ultrasonic probe. It maintains the operational stability of the probe while filtering out harmful radial deflections from the test lance. The cardan coupling allows the probe to remain stable for easy operation while preventing the transmission of radial movements that would compromise measurement precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The rigid mechanical fixation system is replaced with a cardan coupling mechanism that provides a different type of connection. This new mechanical system maintains operational stability through rotational capability while eliminating the direct transmission of radial deflections, thus improving measurement precision without sacrificing ease of operation.

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

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 lightweight, portable, and accurate ultrasonic testing of hollow shafts, ensuring reliable detection of material defects without interference from rotational movements, facilitating easy assembly and disassembly, and supporting various probe configurations for different shaft dimensions.

Implementation Method 1

The invention relates to a device for ultrasonic testing of hollow shafts

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Implementation Method 2

The ultrasonic probe is rotationally connected to the probe. The probe rotates as it moves axially.

Methodology Applied
Scientific EffectSound wave reflection: Reflection

Implementation Method 3

the centering means can, for example, be in the form of spring elements. In particular, two spring elements arranged axially apart from each other can be provided

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4672224A1Decoupled test head
Publication Date: 2025.12.31 KARL DEUT PRUF UND MESSGERATEBAU
  • EP4672224A1 patent drawingFigure 1
  • EP4672224A1 patent drawingFigure 2
  • EP4672224A1 patent drawingFigure 3

AI summary

The invention relates, inter alia, to a device (10) for ultrasonic testing of hollow shafts (11), in particular hollow shafts of railway wheelsets (12), comprising a test lance (14) having an ultrasonic probe (15) with transducers (74a, 74b), which can be inserted into the hollow shaft (11) with a prong end (16), which can be displaced along the hollow shaft (11) by means of a drive (24) in the axial direction (25) by means of which, and which rotates during its axial displacement, wherein the ultrasonic probe (15) is rotationally connected to the test lance (14), wherein the transducers (74a, 74b) are guided along an inner circumferential surface (59) of the hollow shaft (11) with the aid of centering means (70a, 70b), and wherein there is a connection between the prong end (16) of the test lance (14) and the ultrasonic probe (15) a device (78) for radial decoupling of the insertion end (16) from the ultrasonic probe (15) is arranged.