Epicyclic Gear Train for Compact Mechanical Timepiece Movement

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Solution Overview

Problem

Existing mechanical timepiece movements have inefficiencies in their gear trains, leading to a large number of mobile parts, which increases size and energy consumption, and lacks aesthetic appeal due to complex cog structures.

Innovation Solution

A mechanical timepiece movement with an epicyclic gear train that reduces the number of mobile parts by using a planetary gear train with a satellite carrier and intermediate wheel set, allowing for high multiplication ratios and eliminating traditional timer components, thereby reducing size and energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional gear train is used to connect the barrel to the escapement pinion, then the timepiece can function, but the number of mobile parts increases, leading to larger size and higher energy consumption

Engineering Contradiction:
Improveefficiency of the gear trainVSAvoidnumber of mobile parts
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple gear functions into a single planetary gear train system. The planetary gear train combines the functions of speed multiplication and torque transmission that would traditionally require separate gear trains, reducing the number of mobile parts while maintaining reliability and efficiency.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The planetary gear train serves multiple functions simultaneously: it acts as both a speed multiplier and a torque transmitter, and also provides the kinematic connection between the barrel and escapement pinion. This multi-functionality reduces the overall complexity by eliminating the need for separate dedicated gear trains for each function.

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

2Adaptability or versatility

If traditional timer components are included in the gear train, then the timepiece can display hours, but the number of mobile parts increases and the structure becomes more complex

Engineering Contradiction:
Improvetime display functionalityVSAvoidstructure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The planet carrier serves multiple functions: it transmits motion from the barrel, provides the hour indication through its slow rotation, and supports the planetary gears. By making the planet carrier multi-functional, the patent eliminates the need for separate timer components while maintaining time display capability.

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

Solution Approach 2:

The patent combines the hour indication function with the motion transmission function by making the planet carrier also serve as the hour indicator. The slow rotation of the planet carrier (one revolution per 12 hours) directly provides the hour display, merging what would traditionally be separate functions into a single component.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If more mobile parts are used in the gear train, then the timepiece can maintain proper timing, but the size of the movement increases

Engineering Contradiction:
Improvetiming accuracyVSAvoidsize of the movement
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

The planetary gear train segments the gear train into a compact planetary arrangement rather than a linear sequence of gears. This segmentation allows the same timing function to be achieved in a much smaller volume by utilizing the radial arrangement of planetary gears around the sun gear.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The planetary gears are nested within the annular gear, with the planet gears rotating on carriers that are themselves rotating. This nested arrangement allows multiple gear functions to be packed into a small radial space, significantly reducing the overall size of the movement while maintaining timing accuracy.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 achieves a significant reduction in the number of mobile parts, enhancing efficiency and aesthetic appeal by simplifying the gear train and eliminating unnecessary components, resulting in a more compact and energy-efficient timepiece movement.

Implementation Method 1

The finishing train (1, 5) comprises a planetary gear train (6-10)

Methodology Applied
Scientific EffectGear mechanism: Gear

Data Source

PatentEP2515186B1Räderwerk für Uhr
Publication Date: 2014.06.11 CARTIER CRATION STUDIO SA
  • EP2515186B1 patent drawingFigure 1
  • EP2515186B1 patent drawingFigure 2
  • EP2515186B1 patent drawingFigure 3

AI summary

A timepiece is described comprising a mechanical movement including a frame (0), a barrel (1) and an escapement pinion (5) connected by a finishing gear train. This gear train includes a multiplying epicyclic train comprising a first planet gear (6) having a constant rotational speed during the normal operation of the movement, a second planet gear (7) kinematically connected to the escapement pinion (5), at least one satellite (9) each meshing with the first planet gear (6) and the second planet gear (7), and a satellite carrier (8) kinematically connected to the barrel (1) and carrying the satellite(s) (9).