Clock Gear Wheel Fault Detection Using Synchronous Acoustic Analysis

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Solution Overview

Problem

Existing quality control methods for watch components, such as those in watch mechanisms, are imprecise, labor-intensive, and cannot be automated, making it difficult to identify defects in gear trains and optimize watch operation and chronometry.

Innovation Solution

An acoustic diagnostic method that measures perturbations in amplitude to detect defects like malroundness, concentricity, and tooth cutting issues by analyzing the passage of each tooth in a watch movement, using synchronous signal processing and Fourier transforms to identify non-conforming wheels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If visual analysis or FFT analysis is used to detect gear defects, then the inspection process can be performed, but the precision of defect identification is insufficient and the location of the problem origin cannot be determined

Engineering Contradiction:
Improvedefect identification precisionVSAvoidlocation information of defect
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent segments the gear train analysis by associating each measured alternation with a specific wheel based on predetermined tooth counts. By dividing the overall signal into wheel-specific sequences and analyzing each separately, the system can identify both the presence and location of defects in specific gears, resolving the contradiction between detection capability and location information.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If manual observation of signals is used to detect defects, then the analysis can be performed, but the process becomes expensive and time-consuming and cannot be automated

Engineering Contradiction:
Improvedefect detection accuracyVSAvoidinspection efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces manual visual observation with an automated electronic measurement and processing system. The system automatically measures alternations, associates them with specific wheels, superimposes sequences, and detects defects through electronic signal processing, eliminating the need for manual inspection while maintaining high detection accuracy and enabling automation.

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

Solution Approach 2:

The system performs self-diagnosis by automatically analyzing its own measurement data. The defect detection process is autonomous, with the system independently measuring signals, processing them through superposition and sequence association, and identifying defects without external human intervention, thereby achieving both high accuracy and productivity.

Inventive Principle:
Principle #25Self-service

3Device complexity

If measurements are taken at low frequency (e.g., every two seconds), then the acquisition process is simpler, but the resolution is insufficient to trace defects to high-speed components

Engineering Contradiction:
Improvemeasurement system complexityVSAvoiddefect location resolution
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent implements periodic measurement at each alternation (tooth passage) rather than at lower intervals. By measuring at every alternation event, the system captures high-frequency information necessary to trace defects to specific high-speed components while maintaining systematic organization through periodic association with wheel sequences, achieving high resolution without excessive complexity.

Inventive Principle:
Principle #19Periodic action

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 method provides precise identification of defective components, allowing for targeted corrections and improving the efficiency and accuracy of watch quality control, reducing rework and optimizing torque transmission.

Implementation Method 1

detect a plurality of sounds, each sound of the plurality of sounds corresponding to the passage of each tooth of the escape wheel in cooperation with the anchor

Methodology Applied
Scientific EffectAcoustic detection: Sound

Implementation Method 2

measure, at each alternation, a characteristic quantity of the oscillator in operation, such as an amplitude, a rate, a reference point, an actual lift angle

Methodology Applied
Scientific EffectOscillation: Harmonic Oscillator

Data Source

PatentEP4682642A1Gear wheel fault detection by synchronous analysis of gait and/or amplitude
Publication Date: 2026.01.21 RICHEMONT INTERNATIONAL SA
  • EP4682642A1 patent drawingFigure 1~2
  • EP4682642A1 patent drawingFigure 3~4
  • EP4682642A1 patent drawingFigure 5~6

AI summary

Acoustic diagnostic method for detecting a non-conforming wheel of a clock movement, comprising the following steps: - detecting a plurality of sounds, each sound of the plurality of sounds corresponding to the passage of each tooth of the escape wheel over each of the pallets, forming alternations, - measuring, at each alternation, a characteristic quantity of the oscillator in operation, - choosing an alternation sequence associated with a rotation, at least partial, of the escape wheel or of at least one of the wheels of the plurality of wheels, on the basis of the predetermined number of teeth, - stacking, on the chosen alternation sequence, each measurement of the characteristic quantity for each alternation, so as to obtain a synchronous signal, - detecting a variability of the characteristic quantity, - deducing a non-conformity on one wheel of the plurality of wheels.