Watch Tab Indexing Device With Segmented Flanks

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Solution Overview

Problem

Existing zipper indexing devices in timepieces are prone to assembly errors and have inconsistent force production across different configurations, leading to unreliable operation and potential mechanical issues.

Innovation Solution

A zipper indexing device with a spring lever mechanism that includes an indexing body and indexing element with multiple flanks, allowing for the definition of two or three stable axial positions of the zipper, ensuring consistent force application and reducing the risk of assembly errors through a configurable design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a pull spring with a beak is used to define axial positions of a control rod, then the mechanism can be simplified with fewer components, but the force production becomes inconsistent across different configurations

Engineering Contradiction:
Improvenumber of componentsVSAvoidforce consistency
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The indexing element is segmented into multiple independent flanks (first flank, second flank, third flank) that can independently engage with corresponding notches. This segmentation allows each flank to be optimized for its specific engagement, ensuring consistent force production across different configurations while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different flanks of the indexing element have different geometries and engagement characteristics tailored to their specific functions. The first flank engages with a first notch, the second flank with a second notch, and the third flank with a third notch, allowing each local region to provide the appropriate force characteristics for its configuration.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If the beak configuration is changed to define different indexing positions, then the mechanism can accommodate multiple positions, but assembly errors may occur due to incorrect pre-stressing

Engineering Contradiction:
Improvenumber of indexing positionsVSAvoidassembly accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The indexing element is pre-configured with multiple flanks at predetermined angles during manufacturing, so that when assembled, the correct flank automatically engages with the corresponding notch based on the desired configuration. This preliminary configuration eliminates the need for complex assembly decisions and reduces assembly errors.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The indexing element acts as an intermediary component between the pull spring and the control rod, providing a standardized interface with multiple notches. This intermediary structure allows the mechanism to achieve multiple indexing positions while maintaining consistent force production and reducing assembly complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If a single-piece pull-tab spring with beak is used, then the device structure is simplified, but the force application varies depending on beak configuration

Engineering Contradiction:
Improvecomponent structureVSAvoidforce application consistency
Core Design Contradiction:
Device complexityVSForce

Solution Approach 1:

The indexing element features locally optimized flanks with specific geometries tailored to their engagement requirements. Each flank (first, second, and third) has its own angular orientation and engagement characteristics, ensuring that force is consistently applied regardless of which configuration is active.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The indexing element serves multiple functions within a single component: it provides the beak structure for engagement, defines multiple indexing positions through its flanks, and ensures consistent force application across all configurations. This multi-functionality maintains structural simplicity while achieving force consistency.

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

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 reliable and consistent indexing mechanism, reducing the risk of assembly errors and ensuring stable operation by defining distinct axial positions of the zipper, thereby enhancing the mechanical precision and reliability of timepiece mechanisms.

Implementation Method 1

a spring lever mechanism that includes an indexing body and indexing element with multiple flanks

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3955065B1Tab indexing device
Publication Date: 2024.09.04 ROLEX SA
  • EP3955065B1 patent drawingFigure 1~2
  • EP3955065B1 patent drawingFigure 3~4
  • EP3955065B1 patent drawingFigure 5

AI summary

Indexing device (100) for a pull-out (10) for a watch part comprising: - an indexing body (4), and - an indexing element (3) comprising at least two sets of flanks (31a, 31b, 31c; 32a, 32b) for defining indexing positions of the pull-out (10) and mounted on the indexing body (4), the indexing body (4) and the indexing element (3) being arranged or configured so as to define at least two positions, in particular at least two fixing positions, of the indexing element (3) on the indexing body (4).