Parametric Resonator Clock Frequency Adjustment via Stiffness Modulation

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Solution Overview

Problem

Conventional impulse escapements in mechanical watches introduce disturbances that limit chronometric performance, making it challenging to achieve precise timekeeping.

Innovation Solution

A parametric resonator system is used, where a sustaining oscillator regulates the frequency of a resonator by varying parameters such as stiffness and inertia with a frequency between 0.9 and 1.1 times the natural frequency, reducing the influence of the escapement mechanism and enhancing precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional impulse escapement is used in a mechanical watch, then the mechanical timekeeping mechanism can operate, but the chronometric performance is limited due to disturbances introduced by the escapement

Engineering Contradiction:
Improvechronometric performanceVSAvoiddisturbances from escapement
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and removes the escapement mechanism from the timekeeping system. By using a free oscillating resonator (balance wheel with hairspring) that operates independently without an escapement, the harmful periodic disturbances are eliminated while maintaining the essential timekeeping function through magnetic coupling for energy transfer only.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a magnetic coupling field as an intermediary between the sustaining oscillator and the resonator. This magnetic field serves as a non-contact mediator that transfers energy and maintains oscillations without the mechanical interference of a conventional escapement, thereby reducing harmful disturbances.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If a parametric resonator system with sustaining oscillator is used, then frequency stability and precision are improved, but the device complexity increases due to additional components

Engineering Contradiction:
Improvetimekeeping precisionVSAvoidcomplexity of resonator system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the sustaining oscillator and resonator into a single integrated timekeeping unit. The magnetic coupling allows these two functional elements to work together as one cohesive system, reducing overall complexity compared to separate mechanisms while maintaining high precision through parametric resonance.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces the traditional mechanical escapement linkage with a magnetic coupling system. This substitution eliminates complex mechanical connections while achieving the same energy transfer function, thereby reducing device complexity while improving precision through reduced mechanical disturbances.

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

3Stability of the object's composition

If the rigidity of the elastic return means is increased to stabilize frequency, then the frequency stability improves, but the amplitude of oscillation decreases due to increased damping

Engineering Contradiction:
Improvefrequency stabilityVSAvoidoscillation damping
Core Design Contradiction:
Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The patent employs periodic variation of the moment of inertia of the resonator at twice the oscillation frequency. This periodic action compensates for the energy losses caused by increased rigidity, maintaining both frequency stability and sufficient oscillation amplitude by adding energy at the right moments in the oscillation cycle.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent changes the parameter of moment of inertia dynamically during operation. By periodically varying this parameter in sync with the oscillation, the system can maintain stable frequency while compensating for energy losses, effectively decoupling the trade-off between rigidity and damping.

Inventive Principle:
Principle #35Parameter changes

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 approach significantly improves the accuracy of mechanical timepieces by stabilizing the frequency and reducing damping, leading to more precise timekeeping.

Implementation Method 1

at least one elastic return means which comprises at least one hairspring or one torsion wire or one flexible guidance

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a parametric resonator system is used, where a sustaining oscillator regulates the frequency of a resonator by varying parameters such as stiffness and inertia with a frequency between 0.9 and 1.1 times the natural frequency

Methodology Applied
Scientific EffectParametric resonance: Resonance

Data Source

PatentEP2908191B1Adjustment of the frequency of a clock resonator by changing the rigidity of a resilient return means
Publication Date: 2020.03.18 THE SWATCH GRP RES & DEVELONMENT LTD
  • EP2908191B1 patent drawingFigure 1~6
  • EP2908191B1 patent drawingFigure 7~10
  • EP2908191B1 patent drawing

AI summary

A method for regulating the frequency, around its natural frequency (ω0), of a resonator mechanism (1) comprising an elastic return means (40) with a balance spring (4) or a torsion wire (46), wherein a regulating device (2) acts on said resonator mechanism (1) with a periodic motion, with a regulation frequency (ωR) that is between 0.9 times and 1.1 times the value of an integer multiple between 2 and 10 of said natural frequency (ω0), controlling a periodic variation of the real and/or imaginary part of the stiffness of said elastic return means (40). A clockwork movement (10) comprising such a resonator mechanism (1) and such a regulating device (2) arranged to control a periodic variation of the stiffness of said elastic return means (40).