Automatic Barrel Spring Winding With Asymmetrical Planet Gears

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing automatic winding mechanisms for watch mainsprings suffer from high angular speeds leading to lubrication issues, premature wear of pawls, mechanical play causing noise, shocks, and reduced winding efficiency due to 'dead angles', especially with large reduction ratios.

Innovation Solution

The mechanism employs asymmetrical satellite gears on reduction wheels that lock in a predefined direction, minimizing mechanical backlash and reducing rotational speeds through a gear train with specific reduction ratios, ensuring efficient winding regardless of oscillating mass direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional clutch mechanisms with pawls and clutch wheels are used, then automatic winding function is achieved, but high angular speeds cause lubrication problems and premature wear of pawls

Engineering Contradiction:

Improvepawl lifespanVSAvoidangular speed of pawls

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The patent introduces a reduction gear mechanism that changes the rotational speed parameter of the oscillating mass before it reaches the clutch mechanism. By incorporating planet gears and a transmission pinion, the system reduces the high angular speed of the oscillating mass to a lower speed at the clutch wheels, thereby reducing lubrication demands and wear on the pawls while maintaining the automatic winding function

Inventive Principle:

Principle #35Parameter changes

2Reliability

If conventional clutch mechanisms are used, then torque transmission is achieved, but mechanical play between pawls and teeth causes noise, shocks, and premature wear

Engineering Contradiction:

Improvecomponent wear resistanceVSAvoidmechanical play causing noise and shocks

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent employs asymmetrical satellite gears where the planet gears have teeth configured to engage preferentially in one direction. This asymmetrical tooth configuration eliminates mechanical play by ensuring continuous contact between the planet gear teeth and the transmission pinion teeth, preventing the gaps and clearance that cause noise, shocks, and premature wear in conventional symmetrical clutch mechanisms

Inventive Principle:

Principle #4Asymmetry

3Power

If large reduction ratios are used in clutch mechanisms, then torque multiplication is achieved, but dead angles increase causing reduced winding efficiency

Engineering Contradiction:

Improvetorque multiplicationVSAvoidwinding efficiency

Core Design Contradiction:

PowerVSProductivity

Solution Approach 1:

The patent's planet gear mechanism ensures continuous torque transmission by maintaining constant engagement between the planet gears and the transmission pinion throughout the oscillating mass's rotation. The asymmetrical tooth configuration ensures that at least one planet gear is always engaged with the pinion, eliminating dead angles and ensuring the useful action of winding continues without interruption, thereby maintaining high winding efficiency while achieving torque multiplication

Inventive Principle:

Principle #20Continuity of useful action

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 design extends the lifespan of components, reduces vibrations, and enhances winding efficiency by minimizing mechanical play and wear, while maintaining consistent torque transmission.

Implementation Method 1

The satellites (131) include teeth of asymmetrical shape, so as to form pawls configured to lock in rotation, in each of said reduction gears, the transmission pinion (132) and the reduction wheel (130) only when said reduction wheel pivots in a predefined direction of rotation

Methodology Applied

Scientific EffectMechanical locking:

Implementation Method 2

Each reduction wheel (130) has a reduction gear carrying at least four planet gears (131), and a transmission pinion (132) around which the reduction wheel is mounted freely

Methodology Applied

Scientific EffectGear reduction: Gear

Implementation Method 3

a ratchet wheel drive (14) configured to cooperate with a ratchet (not shown in the figures)

Methodology Applied

Scientific EffectRatchet mechanism: Ratchet

Data Source

PatentEP4296788B1Device for automatic winding of a barrel spring of a timepiece movement

Publication Date: 2026.01.07 MONTRES BREGUET SA

Figure 1~2
Figure 3

AI summary

The invention relates to a device (10) for the automatic winding of a watch's mainspring, comprising an oscillating weight (11), an input wheel (12) kinematically linked to the oscillating weight (11), two reduction wheels (13) and a ratchet drive wheel (14), each reduction wheel (13) having a reduction wheel (130) carrying at least four planet gears (131), and a transmission pinion (132) around which the reduction wheel (130) is mounted freely, the input wheel (12) being kinematically linked to the two reduction wheels (130) so that, regardless of the direction of rotation in which it is driven by the oscillating weight (11), it drives the two reduction wheels (130) in rotation in different directions from each other, the planet gears (131) forming, in each of said reduction wheels (13),pawls configured to lock the transmission pinion (132) and the reduction wheel (130) in rotation only when said reduction wheel (130) pivots in a predefined direction of rotation, said predefined direction of rotation being identical for both reduction wheels (130).