Watch Dial Plate Frequency Tuning for Shock Resistance

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Solution Overview

Problem

Existing watch designs face challenges in mechanical shock resistance and acoustic performance due to the lack of effective frequency tuning of acoustic radiation membranes, which can lead to contact and damage during shocks, and inadequate sound radiation in the 0.5 kHz to 5 kHz or 10 kHz frequency band.

Innovation Solution

A frequential tuning process for a set of watch plates, where at least two dial plates are spaced with a low defined distance to prevent contact during mechanical shocks, with one plate made of metallic material and the other of fragile sapphire, allowing them to vibrate in phase and function as acoustic radiation membranes, while adjusting their frequencies to match the first clean mode of vibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If plates are spaced far apart to avoid contact during mechanical shock, then mechanical shock resistance is improved, but watch case space is lost and device complexity increases

Engineering Contradiction:
Improvemechanical shock resistanceVSAvoidwatch case space
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent applies frequency tuning by modifying the natural vibration frequencies of the plates through parameter changes in their mechanical properties. By adjusting the stiffness, mass distribution, or boundary conditions of the plates, their natural frequencies are tuned so that during mechanical shock, the plates vibrate in phase and maintain spacing, preventing contact without requiring excessive clearance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes mechanical vibration principles by analyzing and controlling the natural vibration modes of the plates. Through frequency tuning, the plates are made to resonate at frequencies that ensure they move synchronously during shock events, transforming the potential harmful relative motion into coordinated motion that prevents contact.

Inventive Principle:
Principle #18Mechanical vibration

2Ease of manufacture

If traditional exterior parts are used, then manufacturing is simple, but acoustic efficiency in the 0.5 kHz to 5 kHz frequency band is low

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidacoustic efficiency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent makes the dial plates serve dual functions: they maintain their traditional aesthetic and protective roles while simultaneously functioning as acoustic radiation membranes for the striking mechanism. By tuning the natural frequencies of these existing plates, they become efficient acoustic radiators in the desired frequency band without requiring separate acoustic components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent modifies the mechanical parameters of the dial plates (stiffness, mass, geometry) to tune their natural vibration frequencies to match the desired acoustic radiation frequencies. This parameter adjustment transforms the plates into efficient acoustic membranes while maintaining their original manufacturing simplicity.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If membranes are added to improve acoustic radiation, then acoustic efficiency is improved, but device complexity increases and water resistance may be compromised

Engineering Contradiction:
Improveacoustic efficiencyVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent eliminates the need for separate acoustic membranes by making the existing dial plates perform both their traditional functions and acoustic radiation functions. This multi-functionality approach improves acoustic efficiency without adding components that would complicate the device or compromise water resistance.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent extracts the acoustic radiation function from the concept of separate membranes and integrates it into the existing dial plates. By removing the requirement for additional membrane components, the solution simplifies the device structure while maintaining improved acoustic performance.

Inventive Principle:
Principle #2Taking out (Extraction)

4Ease of manufacture

If frequency tuning is not applied, then manufacturing is simpler, but plates contact during mechanical shock causing breakage

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidcontact prevention during shock
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies frequency tuning by modifying the natural vibration frequencies of the plates through parameter changes in their mechanical properties. By adjusting the stiffness, mass distribution, or boundary conditions of the plates, their natural frequencies are tuned so that during mechanical shock, the plates vibrate in phase and maintain spacing, preventing contact without requiring excessive clearance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent performs frequency tuning as a preliminary action during the manufacturing or assembly process. By pre-adjusting the natural frequencies of the plates before the watch is put into service, the system is prepared to automatically prevent contact during future shock events without requiring active control or additional components.

Inventive Principle:
Principle #10Preliminary 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

The process enhances mechanical shock resistance and acoustic performance by ensuring the sapphire plate does not break and improves the aesthetic and functional aspects of the watch by allowing the plates to vibrate in phase without contact, thus enhancing the acoustic influence of the watch's sound generation.

Implementation Method 1

The plates are tuned in frequency, in particular by controlling for example the first natural mode of vibration

Methodology Applied
Scientific EffectNatural vibration modes: Vibration

Implementation Method 2

The frequencies of the notes generated must be close to the natural vibration modes of the membranes for them to enter into resonance

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 3

the acoustic efficiency, based on the complex vibro-acoustic transduction of the external parts

Methodology Applied
Scientific EffectVibro-acoustic transduction:

Implementation Method 4

the first acoustic radiation membrane is configured to efficiently radiate frequencies in a first frequency band

Methodology Applied
Scientific EffectAcoustic radiation: Acoustic Radiation Pressure

Data Source

PatentEP4113219B1Method for frequency tuning of an assembly of plates of a watch, and watch comprising the assembly of tuned plates
Publication Date: 2025.02.12 MONTRES BREGUET SA
  • EP4113219B1 patent drawingFigure 1~4
  • EP4113219B1 patent drawingFigure 3a~3b

AI summary

The present invention relates to a method for frequency tuning a set of plates (4, 5) of a watch (1). The plates are arranged one above the other, forming a watch dial, with a defined space between them. A mechanical shock is applied to the set of plates, and the vibration frequency of each plate is checked. If the vibration frequency differs from that of the other plates, a frequency adjustment is made to obtain an identical vibration frequency for each plate, thus tuning the plates at least according to the first natural mode of vibration and preventing any contact between the plates following a mechanical shock.