Hairspring Rigidity Adjustment via Flexible Guide Stud Holder

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Solution Overview

Problem

Existing mechanical watch mechanisms face limitations in precise rate adjustment due to complex and space-consuming adjustment systems, particularly with balance springs, leading to potential inaccuracies and inefficiencies in maintaining time accuracy.

Innovation Solution

A timepiece assembly with a hairspring featuring a flexible ribbon and adjustable prestressing means, utilizing a stud holder with a flexible guide to allow precise adjustment of rigidity through a movable secondary body, connected via a flexible element and prestressing mechanism, enabling continuous torque or force application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a traditional rack system with two movable parts is used to adjust the balance spring stiffness, then the rate adjustment capability is improved, but the device complexity and space consumption increase significantly

Engineering Contradiction:
Improverate adjustment precisionVSAvoidadjustment system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The stud holder is divided into two separate bodies: a main body that remains stationary and a secondary body that moves relative to it. This segmentation allows the adjustment mechanism to be simplified while maintaining precision, as only the secondary body needs to be movable rather than requiring two fully movable parts as in traditional rack systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The secondary body is made movable relative to the main body through a flexible guide, enabling dynamic adjustment of the balance spring stiffness. This dynamic capability allows continuous rate adjustment while maintaining a simpler overall structure compared to traditional rack systems that require complex multi-part movable assemblies.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If a traditional rack system with two movable parts is used to adjust the balance spring stiffness, then the rate adjustment capability is improved, but the space occupied on the regulating organ increases significantly

Engineering Contradiction:
Improverate adjustment precisionVSAvoidspace occupied by adjustment system
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

By segmenting the stud holder into a stationary main body and a movable secondary body, the system reduces the total space required. The flexible guide allows the secondary body to move within a constrained path, minimizing the space needed for adjustment while maintaining precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The flexible guide constrains the secondary body to move primarily in a circular path around the main body, utilizing rotational motion to achieve linear adjustment effect. This dimensional transformation allows compact packaging of the adjustment mechanism within the regulating organ.

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

3Measurement precision

If the balance spring is made adjustable by changing effective length with a racket, then the rate accuracy adjustment is possible, but the adjustment precision is limited to a few seconds or tens of seconds per day

Engineering Contradiction:
Improverate accuracyVSAvoidadjustment precision
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

Instead of changing the effective length of the balance spring (racket method), the invention changes the stiffness parameter of the spring by applying variable force or torque through the flexible element. This parameter change approach enables finer adjustment precision, allowing rate adjustment beyond the limited precision of traditional length-adjustment methods.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

A flexible element is introduced as an intermediary between the balance spring and the adjustment mechanism. This flexible element allows precise control of the force applied to the spring, enabling fine-tuned rate adjustment with better precision than direct mechanical adjustment methods.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Measurement precision

If a flexible element with greater rigidity than the ribbon is used in the hairspring, then the rate adjustment precision is improved, but the complexity of the adjustment means increases

Engineering Contradiction:
Improverate adjustment precisionVSAvoidadjustment means complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The flexible element serves as an intermediary component that bridges the adjustment mechanism and the balance spring. By using this intermediate element with controlled rigidity, the system achieves precise rate adjustment while the complexity is managed through the modular design of the flexible element integration.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The flexible element's rigidity can be dynamically adjusted through the prestressing mechanism, allowing the system to optimize performance for different adjustment requirements. This dynamic capability enables precise adjustment without requiring a permanently complex structure.

Inventive Principle:
Principle #15Dynamics

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 provides simpler, compact, and precise rate adjustment, ensuring minimal impact resistance and maintaining high accuracy by allowing continuous adjustment without play, thus enhancing timekeeping precision.

Implementation Method 1

the secondary body being movable relative to the main body connected to the flexible element by a flexible guide

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the adjustment means comprising prestressing means for applying a variable force or torque to the flexible element, so as to vary the rigidity of the flexible element

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4575668A1Timepiece assembly for regulating organ provided with means for adjusting the movement
Publication Date: 2025.06.25 THE SWATCH GRP RES & DEVELONMENT LTD
  • EP4575668A1 patent drawingFigure 1~3
  • EP4575668A1 patent drawingFigure 4
  • EP4575668A1 patent drawing

AI summary

The invention relates to a timepiece assembly for a timepiece regulating organ, said timepiece assembly (10) comprising a hairspring (25) comprising a flexible ribbon (2) wound on itself in several turns, the ribbon (2) having a predefined rigidity, the hairspring (25) comprising means for adjusting its rigidity, the adjustment means comprising a flexible element (5) arranged in series with the ribbon (2), the flexible element (5) connecting one end (4) of said ribbon (2) to a rigid support (17), the flexible element (5) preferably having a rigidity greater than that of the ribbon (2), the adjustment means comprising prestressing means (6) for applying a variable force or torque to the flexible element (5), so as to vary the rigidity of the flexible element (5), said timepiece assembly (10) comprising a stud holder (1) configured to suspend the hairspring (25),the stud holder (1) comprising a main body (30) connected to the flexible element (5), and a secondary body (33) connected to the prestressing means (6), the secondary body (33) being movable relative to the main body (30), characterized in that the secondary body (33) is connected to the main body (30) by a flexible guide (20). The invention also relates to a regulating member (10) comprising such a watch assembly (1).,