Clock Movement Barrel Rotation Speed Optimization

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Solution Overview

Problem

Traditional watch movements with barrels rotating at slow speeds (between one ninth and one sixth of a revolution per hour) face challenges in achieving atypical and innovative minute displays while maintaining chronometric stability, as they are prone to the 'stick-slip' phenomenon and inefficient torque transmission.

Innovation Solution

A double barrel system with coaxial shafts and integrated motor springs, where the barrel performs one revolution in two hours, allowing a double minute hand to rotate with the barrel and reducing friction-related issues, coupled with a gear train that adjusts the rotation speed for hour and second displays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the barrel rotates at traditional slow speeds (one ninth to one sixth of a revolution per hour), then the power reserve is maintained, but the minute display lacks innovation and chronometric stability deteriorates due to stick-slip phenomenon

Engineering Contradiction:
Improvechronometric stabilityVSAvoidstick-slip phenomenon
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the rotation speed parameter of the barrel from traditional slow speeds (one ninth to one sixth of a revolution per hour) to a faster speed (one revolution per hour). This parameter change reduces the stick-slip phenomenon between the barrel and the minute indicator, thereby improving chronometric stability while enabling more dynamic minute display configurations

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the barrel rotates faster (one revolution per hour), then chronometric stability improves and stick-slip phenomenon is reduced, but the torque transmission to the escapement must be optimized

Engineering Contradiction:
Improvechronometric stabilityVSAvoidtorque transmission
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The patent introduces a gear train as an intermediary mechanism between the barrel and the escapement. This gear train includes a minute wheel and other gears that transfer and optimize the torque from the faster-rotating barrel to the escapement, ensuring proper power transmission while maintaining the improved chronometric stability

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If a double minute hand configuration is used with the barrel rotating once per hour, then an innovative minute display is achieved, but the device complexity increases

Engineering Contradiction:
Improveminute display configurationVSAvoiddouble barrel system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent makes the barrel serve multiple functions: it acts as both the energy storage drum for the mainspring and the direct carrier of the minute indicator. By rotating once per hour, the barrel simultaneously provides power accumulation and innovative time display, eliminating the need for separate traditional minute wheels and reducing overall device complexity despite the double minute hand configuration

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 configuration enhances chronometric stability by reducing friction-related issues and optimizing torque transmission, enabling a more precise and innovative minute display with improved power reserve and reduced disturbances to the escapement.

Implementation Method 1

a first motor spring (13) arranged inside said first drum (11) and a second motor spring (16) arranged inside said second drum (14), said first and second motor springs making respectively at least twenty-four turns in said first and second drums

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The indicator 2 is mounted in friction on the upper cover 15. The indicator 2 therefore rotates with the first drum 11 as well as with the second drum 14 of the barrel 1 during the running of the movement

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3168693B1Clock movement
Publication Date: 2018.11.07 CARTIER INTERNATIONAL AG
  • EP3168693B1 patent drawingFigure 1
  • EP3168693B1 patent drawingFigure 2
  • EP3168693B1 patent drawingFigure 3

AI summary

A clockwork mechanism comprising a mainspring barrel (1) for transmitting energy to a gear train of the movement and a time display comprising at least one minute indicator (2), characterized in that said minute indicator (2) is carried by the mainspring barrel (1). Preferably, the rotational speed of the mainspring barrel (1) is half a turn or one turn per hour.