Watch Casing Subassembly with Bayonet Fit and Elastic Indexing

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Solution Overview

Problem

The dressing of watches and similar devices faces challenges in achieving secure, sealed, and precisely indexed angular orientations of trim components while preventing involuntary disassembly, which often requires after-sales interventions for sealing, cleaning, or repair.

Innovation Solution

A sub-assembly comprising a first component with projecting flanges and a second component with wings, arranged to transition from a disassembled to an assembled position through a bayonet fit, utilizing a third component like an elastic rod for angular indexing and locking, allowing reversible assembly and disassembly with minimal operator effort.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional sealing and fixing methods are used for trim components, then secure assembly and sealing are achieved, but angular indexing precision and ease of adjustment are compromised

Engineering Contradiction:
Improvesecure assembly and sealingVSAvoidangular indexing precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The indexing mechanism is segmented into discrete angular positions using notches on the first component and corresponding protrusions on the second component. This segmentation allows for precise angular positioning while maintaining secure assembly, resolving the contradiction between reliability and measurement precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A seal element is introduced as an intermediary component between the first and second components. This seal ensures reliable sealing while the bayonet fitting mechanism provides both secure mechanical connection and precise angular indexing, allowing all three requirements to coexist.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If traditional fixed angular positioning is used, then angular indexing is achieved, but ease of disassembly and reassembly is compromised

Engineering Contradiction:
Improveangular indexingVSAvoidease of disassembly and reassembly
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The connection mechanism transitions from a static fixed position to a dynamic bayonet fitting system that allows controlled movement. The component can be easily inserted and rotated into indexed positions, and equally easily removed by reversing the rotation, maintaining both angular precision and operational ease.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Instead of requiring complex tools or procedures for disassembly, the design allows simple reverse operation. The same rotational motion used for assembly and indexing can be reversed for disassembly, making the process equally easy in both directions while maintaining precise angular positioning.

Inventive Principle:
Principle #13The other way round (Inversion)

3Reliability

If secure locking mechanism is implemented, then prevention of involuntary disassembly is achieved, but device complexity increases

Engineering Contradiction:
Improveprevention of involuntary disassemblyVSAvoidassembly structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking function, sealing function, and angular indexing function are merged into a single bayonet fitting mechanism. The interlocking flanges and wings provide both mechanical locking and angular positioning, while the seal element provides sealing, eliminating the need for separate components for each function and reducing overall complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The bayonet fitting mechanism serves multiple functions simultaneously: it provides secure mechanical locking to prevent involuntary disassembly, ensures precise angular indexing through notches and protrusions, and maintains sealing through the integrated seal element. This multi-functionality reduces the number of separate components needed.

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

4Reliability

If multiple separate components are used for sealing and fixing, then reliable sealing and secure assembly are achieved, but manufacturing cost and assembly complexity increase

Engineering Contradiction:
Improvesealing and assembly securityVSAvoidmanufacturing cost and assembly complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The design merges the sealing component and fixing mechanism into an integrated assembly. The seal element is positioned within the bayonet fitting structure, allowing both sealing and mechanical connection to be achieved with fewer separate parts, reducing manufacturing cost and assembly complexity while maintaining reliability.

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

Ensures a sealed and secure assembly with easy angular indexing, preventing unexpected disassembly and allowing for precise adjustment, while maintaining low component costs and compatibility with various materials, including ceramics and precious stones, without the need for external fixing elements.

Implementation Method 1

comprising a third component in the form of a ring, which comprises an elastic deformable zone arranged to cooperate, in a plane passing through the groove, in angular indexing and locking with a lug, respectively a housing, which comprises that of the first component and second component

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3276187B1Casing subassembly for a timepiece, watch or jewel
Publication Date: 2019.09.18 OMEGA SA
  • EP3276187B1 patent drawingFigure 1~6
  • EP3276187B1 patent drawingFigure 3~9

AI summary

A subassembly (100) for a watch or jewelry component, comprising a first component (1) and a second component (10), arranged for a bayonet fit between two rims (2) and two wings (12) of this first component (1) and this second component (10), and adapted to occupy an assembled and indexed position of the first (1) and second (10) components, this subassembly (100) comprising a third ring-shaped component (30), interposed between the first (1) and second (10) components and comprising a ring (31) housed in a groove (131) of the first (1) or second (10) component, this third component (30) comprising a rotational stop (33, 34) relative to the first (1) or second (10) component, and a radially raised elastic zone (32) cooperating in angular indexing with a lug (132) of the first (1) or second (10) component (10) component which is free to rotate relative to the third component (30).