Oscillating Weight Assembly for Damage-Free Self-Winding Watches

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Solution Overview

Problem

Existing automatic watch winding mechanisms face challenges in assembling a peripheral weight onto an automatic movement without causing damage during assembly, requiring complex machining and assembly operations.

Innovation Solution

A self-winding watch mechanism with an oscillating mass comprising a toothed ring, inertial mass, and movable bearing ring, secured by fasteners such as screws, allowing for simple assembly and integration of decorative components like a flange, which can be made of various materials for aesthetic customization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional assembly methods are used for attaching peripheral weight to automatic movement, then secure connection is achieved, but assembly complexity increases and risk of damage during assembly occurs

Engineering Contradiction:
Improvesecure connectionVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The oscillating mass is divided into multiple components: a first component (toothed ring with bearing), a second component (peripheral weight), and a third component (flange). These segmented components are assembled together using simple snap-fitting or press-fitting operations, avoiding complex machining and reducing assembly risk while maintaining secure connection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces intermediate components such as the flange and bearing structure that mediate between the automatic movement and the peripheral weight. These intermediaries simplify the connection interface, enabling easy assembly without direct complex attachment between the movement and weight components.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If traditional machining operations are performed on gold or hard metal components, then precise fitting is achieved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvefitting precisionVSAvoidmanufacturing simplicity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

By segmenting the oscillating mass into separate components with standardized interfaces, the patent eliminates the need for complex machining operations on precious or hard materials. Each component can be manufactured using simpler processes, reducing both manufacturing complexity and cost while maintaining precise fitting through standardized connection features.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs simpler, more manufacturable materials and component designs that can be produced through less expensive machining operations. The segmented architecture allows components to be manufactured with standard tolerances rather than requiring high-precision machining of expensive materials.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Strength

If the oscillating mass is designed as a single integrated component, then structural integrity is maintained, but assembly operations become complex and time-consuming

Engineering Contradiction:
Improvestructural integrityVSAvoidassembly speed
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The oscillating mass is segmented into multiple components that can be assembled through simple snap-fitting or press-fitting operations. This segmentation enables parallel assembly processes and reduces assembly time, while the components maintain structural integrity through their interlocking design and secure connection features.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple functional components (toothed ring, bearing, peripheral weight, flange) are merged into a single oscillating mass assembly that functions as one integrated unit during operation. This merging maintains structural integrity while the segmented assembly process improves productivity.

Inventive Principle:
Principle #5Merging (Combining)

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

Facilitates easy assembly without damaging components, simplifies manufacturing, reduces costs, and enhances winding power while allowing for decorative personalization of the watch.

Implementation Method 1

at least one inertial mass (4) with a non-zero imbalance with respect to said mass axis (D)

Methodology Applied
Scientific EffectInertial force: Inertia

Implementation Method 2

at least one toothed ring (2) with teeth (3) arranged for driving an energy storage device (20)

Methodology Applied
Scientific EffectGear mechanism: Gear

Implementation Method 3

a movable bearing ring (6) which constitutes second guiding means (15)

Methodology Applied
Scientific EffectFriction reduction: Lubrication

Data Source

PatentEP3964896B1Mechanism for self-winding of a watch with oscillating weight
Publication Date: 2025.12.24 BLANCPAIN SA
  • EP3964896B1 patent drawingFigure 1~3
  • EP3964896B1 patent drawingFigure 4~5
  • EP3964896B1 patent drawingFigure 6~7

AI summary

Automatic watch winding mechanism (100) comprising an oscillating mass (1) having a toothed ring (2) for driving an energy storage device (20), and an inertial mass (4) with an eccentric imbalance, the mechanism (100) comprising rotational guidance means for the rotational guidance of the oscillating mass (1) with first guidance means fixed to a structure of the watch, and second guidance means carried by the oscillating mass (1), which comprises, distinct from one another, superimposed at least two by two, and fixed securely at least two by two, more particularly to one another, constituents which are at least a toothed ring (2), at least an inertial mass (4), at least a movable bearing ring (6) constituting second guidance means, and in a variant at least a cover flange (7).