Mechanical Braking for Watch Oscillator Frequency Regulation

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Solution Overview

Problem

Existing watch movements face challenges in accurately regulating the frequency of mechanical oscillators without disturbing the mechanical resonator, leading to precision issues and potential time drift, especially when electronic regulation is deactivated.

Innovation Solution

A watch assembly with a mechanical movement that incorporates a regulation module applying mechanical braking pulses to the balance-spring, allowing for precise frequency regulation without modifying the mechanical oscillator's kinematic properties, using a sensor to detect the balance-spring's neutral position and applying braking pulses in specific alternations to correct temporal drift.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If electromagnetic braking is used to regulate the mechanical oscillator, then frequency regulation is achieved, but the mechanical resonator is disturbed and magnetic fields may damage magnetic elements

Engineering Contradiction:
Improvefrequency regulation precisionVSAvoidmagnetic field damage to magnetic elements
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the electromagnetic braking system with a purely mechanical regulation system. A mechanical resonator regulator applies mechanical forces directly to the balance-spring through a mechanical coupling mechanism, eliminating the need for magnetic fields and coils. This substitution resolves the contradiction by achieving frequency regulation without exposing magnetic elements to harmful magnetic fields.

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

Solution Approach 2:

The patent introduces a mechanical intermediary component (the mechanical resonator regulator) that mediates between the electronic control signal and the mechanical oscillator. This intermediary converts electronic regulation commands into mechanical adjustments of the balance-spring, providing precise frequency control without direct electromagnetic interaction with magnetic elements.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the mechanical resonator is modified to enable electronic regulation, then frequency control is possible, but the mechanical movement design is altered

Engineering Contradiction:
Improvefrequency control capabilityVSAvoidmechanical movement design complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the timepiece into independent functional modules: the original mechanical movement remains unchanged, while a separate mechanical resonator regulator module is added. This modular approach allows frequency control capability to be added without modifying the core mechanical movement design, maintaining simplicity while enabling adaptability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mechanical resonator regulator is designed as a universal interface that can be integrated with standard mechanical oscillators without requiring custom modifications to the movement. The regulator accepts standard mechanical coupling and provides frequency control, making the system adaptable while preserving the original movement design.

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

3Use of energy by moving object

If electronic regulation is deactivated, then energy consumption is reduced, but time drift occurs due to lack of frequency correction

Engineering Contradiction:
Improveenergy consumptionVSAvoidtimekeeping accuracy
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The mechanical resonator regulator is designed to operate passively once mechanically coupled to the oscillator, using the oscillator's own motion to drive the regulation mechanism. This self-service approach allows continuous frequency correction without requiring active electronic power consumption, maintaining timekeeping accuracy while minimizing energy use.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The regulation mechanism operates periodically in sync with the oscillator's natural frequency, applying corrective forces only when needed during each oscillation cycle. This periodic action ensures continuous accuracy maintenance with minimal energy expenditure, as the system leverages the inherent rhythm of the mechanical oscillator rather than requiring constant active control.

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

The solution ensures high precision and robustness, maintaining accuracy even after external disturbances, and allows for the integration of electronic regulation without altering the mechanical movement's design, ensuring the watch remains functional with or without electronic assistance.

Implementation Method 1

The actuator comprises a piezoelectric element supplied by a circuit which generates an electric voltage as a function of a control signal supplied by the regulation circuit. When the piezoelectric element is momentarily energized, the braking member comes into contact with a braking surface of the balance-spring to brake it.

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

the braking member and the balance-spring are arranged in such a way that the mechanical braking pulses are applied by a dynamic dry friction or a viscous friction between the braking member and the braking surface

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3339982B1Regulation by mechanical breaking of a horological mechanical oscillator
Publication Date: 2021.08.25 THE SWATCH GRP RES & DEVELONMENT LTD
  • EP3339982B1 patent drawingFigure 1
  • EP3339982B1 patent drawingFigure 2
  • EP3339982B1 patent drawingFigure 3

AI summary

The timepiece comprises a mechanical movement equipped with a mechanical oscillator, formed by a balance-spring type resonator (14), and a device for regulating its oscillation frequency using an auxiliary oscillator equipped with a quartz resonator. The regulating device includes a sensor (34), arranged to detect the resonator passing through its neutral position, a measuring device arranged to measure, based on position signals provided by the sensor, a time drift of the mechanical oscillator relative to the auxiliary oscillator, and a device (36) for applying mechanical braking pulses to the resonator when a certain time drift is detected. For this purpose, the resonator has a braking surface extending over at least one sector of a certain length along the axis of oscillation, against which a braking element can bear to momentarily brake the resonator.