Torque Variator Clutch Rocker for Watch Rate Precision

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Solution Overview

Problem

Existing mechanical watch movements face challenges in maintaining rate precision due to variations in torque availability, especially when complications like chronographs operate, and the movement's position (worn or stationary) affects its accuracy.

Innovation Solution

A clutch rocker mechanism that alternates between engaged and disengaged positions to modify torque delivery from the barrel to the going train, allowing auxiliary torque to compensate for torque drops during complications and optimizing power reserve based on the watch's usage state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the barrel releases torque to the going train, then the mechanical oscillator can maintain its oscillations, but the rate precision deteriorates when complications take a fraction of the torque

Engineering Contradiction:
Improverate precisionVSAvoidtorque availability
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies the dynamics principle by making the torque transmission path dynamic through the clutch rocker mechanism. The clutch rocker can alternately engage and disengage, switching between a first position where torque is transmitted from the barrel drum to the going train, and a second position where torque is transmitted from the barrel arbor to the going train. This dynamic switching allows the system to adapt torque delivery based on the operational state, ensuring stable rate precision even when complications consume torque.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by varying the torque delivery parameters through the clutch mechanism. By changing the engagement state of the clutch rocker between first and second positions, the system modifies the torque parameter delivered to the going train. This allows optimization of torque availability to maintain the mechanical oscillator's rate precision under varying conditions, including when complications are active.

Inventive Principle:
Principle #35Parameter changes

2Power

If two barrels are used to release more torque, then the torque available to the going train increases, but the device complexity increases

Engineering Contradiction:
Improvetorque outputVSAvoidbarrel structure
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent applies the universality principle by enabling a single barrel to perform multiple functions through the clutch rocker mechanism. The same barrel can deliver torque to the going train through two different paths: directly from the barrel drum or from the barrel arbor. This multi-functionality allows the single barrel to provide variable torque output without requiring two separate barrels, thereby avoiding the complexity of dual-barrel construction while still achieving increased torque availability when needed.

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

This solution ensures stable rate precision by providing additional torque when needed and conserving power reserve when the watch is stationary, thereby enhancing the overall performance and longevity of the mechanical oscillator.

Implementation Method 1

the elastic potential energy stored in a barrel is proportional to its power reserve, to the torque it releases and to its angular speed

Methodology Applied
Scientific EffectElastic potential energy: Elasticity

Implementation Method 2

the clutch rocker carries a clutch mobile arranged to establish a kinematic connection between the ratchet and the mobile of the going train

Methodology Applied
Scientific EffectKinematic connection: Mechanical Force

Data Source

PatentEP2288967B1Timepiece movement comprising a torque variator and timepiece comprising such a movement
Publication Date: 2011.11.02 LA FAB DU TEMPS
  • EP2288967B1 patent drawingFigure 1

AI summary

The invention relates to a timepiece movement comprising a barrel (2) provided with a drum (3) having a peripheral toothing and housing at least one barrel spring fixed to the drum by a first end and to a barrel arbor (4) by a second end, the arbor being fixed to a ratchet (10) of the barrel. The movement also comprises a finishing mechanism, a mobile part (6) thereof being engaged with the toothing of the barrel, and an engagement rocker (20) that can be alternately moved between a first position and a second position, respectively engaged and disengaged, in response to a pre-defined action, the engagement rocker carrying a mobile engagement mechanism (27) arranged in such a way as to establish a kinematic connection between the ratchet and the mobile of the finishing mechanism in the engaged position, and to interrupt said connection in the disengaged position.