Chronograph Watch Gear Train Floating Error

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Solution Overview

Problem

Conventional chronograph watches with permanent seconds displays experience floating and imprecision due to gear backlash at the end of the gear train, leading to irregular rotations and energy losses when friction is used to correct this issue.

Innovation Solution

Incorporating a second loosely mounted middle wheel engaged between the permanent seconds wheel and the chronograph seconds wheel, which repositions the permanent seconds wheel within the gear train, eliminating random angular displacements and the impression of floating without relying on friction or inducing energy losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the permanent seconds wheel is placed at the end of the gear train, then the structure is simplified, but the permanent seconds display member floats and appears imprecise due to gear backlash

Engineering Contradiction:
Improvegear train structureVSAvoidpermanent seconds display precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The gear train is segmented into two paths: one for the permanent seconds wheel and another for the chronograph seconds wheel, both branching from the same intermediate gear. This segmentation allows the permanent seconds wheel to be positioned in the middle of the gear train rather than at the end, providing structural support while maintaining functional independence.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

An intermediate gear is introduced as a mediator that receives power from the main gear train and distributes it to both the permanent seconds wheel and the chronograph seconds wheel. This intermediary structure provides a stable reference point for the permanent seconds wheel, eliminating the floating effect caused by being at the end of the gear train.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If friction is applied to the permanent seconds wheel to eliminate random angular displacements, then the floating impression is reduced, but energy losses increase

Engineering Contradiction:
Improvepermanent seconds wheel stabilityVSAvoidenergy losses from friction
Core Design Contradiction:
Stability of the object's compositionVSLoss of energy

Solution Approach 1:

A dedicated intermediate gear is introduced between the main gear train and the permanent seconds wheel to act as a stable mounting reference. This intermediary structure provides mechanical support that eliminates random angular displacements without requiring friction, thereby avoiding energy losses while achieving the desired stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of applying continuous friction to eliminate all angular play, the invention uses a partial mechanical support structure (the intermediate gear mounting) that provides sufficient stability for the permanent seconds wheel without the excessive energy dissipation that continuous friction would cause.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2053474B1Chronograph timepiece
Publication Date: 2012.12.12 OMEGA SA
  • EP2053474B1 patent drawingFigure 1
  • EP2053474B1 patent drawingFigure 2

AI summary

The present invention relates to a chronograph watch equipped with a finishing train comprising: - a permanent seconds wheel (9) fixed to a permanent seconds display element, - a chronograph seconds wheel (10) cooperating with a clutch (20) to engage with a chronograph seconds display element, and - a center wheel (8) comprising a first center wheel (15) mounted fixedly for rotation, meshing either with the permanent seconds wheel (9) or with the chronograph seconds wheel (10). The finishing train also includes a second center wheel (16) mounted freely, meshing, on the one hand, with the permanent seconds wheel (9), and on the other hand, with the chronograph seconds wheel (10).