Watch Case-Back Ring for Watertight Angular Indexing

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Solution Overview

Problem

Existing watch casing technologies face challenges in achieving watertight and secure assembly with angular indexing, often requiring complex components and materials that degrade over time, and are limited to specific shapes.

Innovation Solution

A device comprising a ring with positioning means and ribs made of deformable material, such as Asutane® or Hytrel®, ensures secure and watertight attachment of the case back to the watch case with adjustable angular indexing, using a compact design and minimal components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If elastic closure elements are used for sealing and indexing, then sealing function is provided, but the device becomes bulky

Engineering Contradiction:
Improvesealing functionVSAvoiddevice bulk
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent combines the sealing function and angular indexing function into a single integrated ring element. The ring includes an elastic portion for sealing and positioning means with indexing features (such as protrusions fitting into recesses) all in one component, eliminating the need for separate elastic closure elements and reducing overall device bulk.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The ring element serves multiple functions simultaneously: it provides sealing through its elastic portion, ensures angular indexing through positioning means with geometric features, and acts as a structural connector between the case back and case. This multi-functionality reduces the number of components needed.

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

2Reliability

If compressible material pads are used for elasticity, then sealing is achieved, but the elasticity changes significantly during material aging

Engineering Contradiction:
ImprovesealingVSAvoidmaterial aging stability
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent uses a composite structure where the ring is made from materials with complementary properties. The elastic portion uses materials designed to maintain consistent elastic properties over time, while the positioning means uses rigid materials for stable geometric features. This composite approach mitigates the degradation issues of single materials.

Inventive Principle:
Principle #40Composite materials

3Manufacturing precision

If angular indexing is achieved through complex tightening and sealing, then proper alignment is obtained, but the device complexity increases

Engineering Contradiction:
Improveangular indexing precisionVSAvoidassembly complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The ring is divided into distinct functional portions: an elastic portion for sealing and a positioning means with indexing features. This segmentation allows each portion to be optimized independently while simplifying the overall assembly process, as the positioning features guide alignment without requiring complex tightening procedures.

Inventive Principle:
Principle #1Segmentation

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 a secure, watertight, and easily adjustable angular indexing of watch components, preventing accidental disassembly while maintaining alignment and reducing manufacturing costs.

Implementation Method 1

The ring 4 comprises an upper portion 40 ensuring the sealing and a middle portion 41 comprising positioning means 3 for ensuring the indexing of the case back 2 relative to the case 1

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3958068B1Device for attaching a back cover on a middle for a clockpiece
Publication Date: 2025.11.05 THE SWATCH GRP RES & DEVELONMENT LTD
  • EP3958068B1 patent drawingFigure 1a~3
  • EP3958068B1 patent drawingFigure 4~5

AI summary

The invention relates to a device for fixing a case back to a watch case, the case back comprising a cover arranged to form a bearing surface with the case and a body arranged to rest in the case, said device comprising a ring disposed between the case back and the case, said ring being arranged to ensure the sealing and indexing of the case back, characterized in that the ring comprises an upper part ensuring the sealing and a middle part comprising positioning means to ensure precise placement of the case back.