Watch Component Assembly With Elastic Retention for Stable Closing Force

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Solution Overview

Problem

Existing watch case assembly methods using precious materials like gold or platinum face challenges in achieving precise and consistent closing forces, leading to rework and waste due to material deformation, and instability over time, especially with multiple assembly/disassembly cycles.

Innovation Solution

A device utilizing an assembly member with elastic zones that cooperate with a hook-shaped shoulder on the bezel, allowing for easy assembly and secure retention by deforming elastically to maintain a stable closing force, even after repeated cycles, using materials like steel or ceramics that are more deformable than precious metals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If precious materials like gold or platinum are used for watch cases, then aesthetic appearance and durability are improved, but manufacturing precision and consistency of closing force deteriorate due to material deformation

Engineering Contradiction:
Improveaesthetic appearanceVSAvoidclosing force consistency
Core Design Contradiction:
ShapeVSManufacturing precision

Solution Approach 1:

The assembly device is divided into separate functional components: a flexible assembly member (3) that can be compressed, a groove (22) in the case (2), and a shoulder (12) on the bezel (1). This segmentation allows the flexible element to be independently manufactured and replaced without affecting the precious metal case components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The flexible assembly member (3) acts as an intermediary between the case (2) and bezel (1). It provides the necessary flexibility and closing force while being replaceable and independent from the precious metal components, solving the contradiction between material durability and manufacturing precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If traditional screw-on case backs are used, then secure assembly is achieved, but aesthetic appearance deteriorates due to visible screws and ratchets

Engineering Contradiction:
Improveassembly securityVSAvoidaesthetic appearance
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The visible fastening elements (screws and ratchets) are extracted from the assembly mechanism. The flexible assembly member (3) provides secure holding through elastic deformation alone, eliminating the need for visible fasteners and achieving both security and aesthetics.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The assembly member (3) is made of flexible material that can be compressed and elastically deformed. This flexible element provides secure assembly through elastic force while remaining invisible when assembled, achieving both reliability and aesthetic appearance.

Inventive Principle:
Principle #30Flexible shells and thin films

3Ease of operation

If flexible elements are compressed to assemble bezel onto case, then assembly is simplified, but stability of closing force deteriorates over time and assembly/disassembly cycles

Engineering Contradiction:
Improveassembly simplicityVSAvoidclosing force stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The assembly member (3) is designed to be dynamically compressible during assembly, then elastically deform to provide stable retention. The flexible material allows temporary compression for easy assembly, then maintains stable closing force through elastic recovery and consistent material properties.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The flexible assembly member (3) changes its physical state from compressed (during assembly) to elastically deformed (during retention). This parameter change allows simple assembly operations while maintaining stable closing force through controlled elastic deformation and material properties.

Inventive Principle:
Principle #35Parameter changes

4Duration of action of stationary object

If precious materials are used for all components, then durability is improved, but ease of repair and replacement deteriorates due to high cost and complexity

Engineering Contradiction:
Improvecomponent durabilityVSAvoidcomponent replaceability
Core Design Contradiction:
Duration of action of stationary objectVSEase of repair

Solution Approach 1:

The assembly device is segmented into replaceable components: the flexible assembly member (3) can be independently replaced without affecting the precious metal case (2) or bezel (1). This segmentation enables easy repair and replacement of the flexible element while preserving the durability of the expensive components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The flexible assembly member (3) is made of less expensive, more replaceable material compared to the precious metal components. If the flexible element deteriorates or needs replacement, it can be easily replaced without affecting the durable but expensive case and bezel, improving ease of repair.

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

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

Enables reliable, quick, and aesthetically pleasing assembly with reduced waste and rework, maintaining consistent assembly strength over time, and allowing for easy replacement of the assembly element without replacing expensive components.

Implementation Method 1

the assembly member includes at least one elastic assembly zone (31) arranged to cooperate with the assembly portion (12) of the first component (1) and arranged to be deformable between a rest position and a position of maximum deformation

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4256406B1Device for assembling two watch components
Publication Date: 2026.01.28 PATEK PHILIPPE SA
  • EP4256406B1 patent drawingFigure 1
  • EP4256406B1 patent drawingFigure 2a~2b
  • EP4256406B1 patent drawingFigure 3a~3b

AI summary

The present invention relates to a device for assembling two timepiece components comprising a first timepiece component (1) and a second timepiece component (2) intended to be assembled to each other by means of at least one assembling member (3), the assembling member (3) being retained on the second component (2) and being arranged to cooperate with at least one assembling portion (12) provided on the first component (1) in order to assemble the first component (1) on the second component (2), the assembling member (3) comprising at least one resilient region (31) intended to cooperate with the assembling portion (12) of the first component (1) and arranged such that it can be deformed between a rest position and a maximum deformation position. The assembling member (3) is a part that is attached to the second component (2).