Timepiece Pivot Bearing Geometry for Smooth Pivot Insertion

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Solution Overview

Problem

Existing methods for manufacturing pivot bearings for watches are not optimized, limiting the ability to produce all desired shapes and materials, particularly causing issues with the insertion of pivots due to sharp edges between recess and pivoting zones.

Innovation Solution

A method involving drilling a hole in a bearing blank, followed by laser engraving a second clearance zone with a femtosecond laser, and removing material by wear to create a smooth connection between the first pivoting zone and the clearance zone, eliminating sharp edges and allowing for various shapes and materials like synthetic ruby or ceramic.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a sharp edge separates the hollow and pivoting surface in traditional stones, then the structure is simple and easy to manufacture, but the pivot can come up against the edge and become marked during insertion

Engineering Contradiction:
Improvepivot insertionVSAvoidbearing geometry
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent applies curvature by replacing the sharp edge separation with a rounded transition zone. The hollow and pivoting surface are connected through a curved surface that eliminates abrupt edges, allowing the pivot to pass through smoothly without being marked or damaged during insertion.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent creates the rounded transition zone in advance during the manufacturing process, using laser technology to pre-form the smooth connecting surface before the pivot insertion occurs. This preliminary shaping prevents potential damage to the pivot during assembly.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If traditional drilling and shaping methods are used, then the manufacturing process is simple, but all desired shapes and materials cannot be produced

Engineering Contradiction:
Improveshape and material varietyVSAvoidmanufacturing process
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical drilling and shaping methods with laser technology. The laser can precisely remove material from various materials (including transparent materials like synthetic ruby) to create complex geometries that would be difficult or impossible to achieve with conventional mechanical tools, thereby enabling greater shape and material versatility.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes laser parameters (energy, pulse duration, focal point) to precisely control material removal and create diverse bearing shapes. By adjusting laser parameters, the same manufacturing system can produce various geometries and work with different materials, enhancing adaptability without requiring multiple specialized tools.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If laser engraving and material removal by wear are used, then smooth transitions and durability are enhanced, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvebearing durabilityVSAvoidmanufacturing process
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses laser technology to create smooth transitions and enhance durability by precisely removing material to form optimal bearing geometries. The laser process creates smooth surfaces and precise transitions that improve pivot insertion and overall bearing reliability, compensating for the increased process complexity through superior product quality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

This method optimizes the manufacturing of pivot bearings by minimizing the risk of damage during pivot insertion, enabling the production of bearings with smooth transitions and enhanced durability, facilitating the use of transparent materials like synthetic ruby.

Implementation Method 1

Laser engraving in the blank, in particular with a femtosecond laser, a second bearing clearance zone

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

Removing material by wear, in particular by olive-cutting, at the start of a first pivoting zone

Methodology Applied
Scientific EffectWear: Wear

Data Source

PatentEP4018268B1Method for manufacturing a timepiece bearing
Publication Date: 2024.09.04 ROLEX SA
  • EP4018268B1 patent drawingFigure 1
  • EP4018268B1 patent drawingFigure 2
  • EP4018268B1 patent drawingFigure 3~6

AI summary

Disclosed is a method for manufacturing a pivot bearing (1) for the pivoting of a timepiece component (2), in particular a pivot stone, characterised in that it comprises the following steps: - Boring (E1) a hole (10a) in a bearing (1) blank (1a) along an axis (A1) intended for the pivoting of a timepiece component (2), this hole (10a) forming a start point (13a) of a first pivot zone (13) of the bearing (1), then - Laser engraving (E2), in the blank (1a), in particular using a femtosecond laser, a second clearance zone (14) of the bearing (1), juxtaposed with the start point (13a) of a first pivot zone (13), this second clearance zone (14) of the bearing (1) opening at a first face (11a) of the bearing (1) blank (1a), then - Removing material by means of wear (E3), in particular by olive-cutting, at the start point (13a) of a first pivot zone (13) of the bearing (1) and a boundary zone (14a) between the start point (13a) of a first pivot zone (13) of the bearing (1) and the second clearance zone (14) of the bearing (1) in order to form a first pivot zone (13) and a second clearance zone (14) of the bearing (1) that are juxtaposed, being connected to each other by a rounded connection.