Watch Conversion Mechanism for Unidirectional Winding

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Solution Overview

Problem

Existing automatic winding mechanisms for watches, such as bidirectional systems, face inefficiencies due to increased stresses and reduced longevity caused by bidirectional rotation, which results in higher braking and dead angles, leading to reduced performance.

Innovation Solution

A conversion mechanism utilizing a first mobile with a pivoting plate and guide member driving a transmission member eccentrically, coupled with a clutch member that employs wedging for unidirectional rotation, reducing stresses and increasing efficiency by allowing the mechanism to operate effectively in one direction while releasing in the opposite.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a bidirectional automatic winding mechanism is used, then the watch can be wound in both directions of oscillation, but the stresses and dead angles increase, reducing performance and longevity

Engineering Contradiction:
Improvebidirectional winding capabilityVSAvoidmechanism longevity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The automatic winding mechanism is segmented into two independent freewheel clutches (first and second freewheel clutches), each handling one direction of rotation. This segmentation allows each clutch to operate independently, reducing the stress and dead angles that would occur in a bidirectional system by distributing the winding function across separate unidirectional components.

Inventive Principle:
Principle #1Segmentation

2Productivity

If bidirectional rotation is implemented, then both oscillation directions can wind the mainspring, but braking and dead angles increase, reducing efficiency

Engineering Contradiction:
Improvewinding efficiencyVSAvoidbraking and dead angles
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

By dividing the winding function into two separate unidirectional freewheel clutches, each clutch operates continuously in its designated direction without the need to reverse or engage/disengage. This eliminates the braking and dead angles inherent in bidirectional mechanisms, as each clutch maintains constant engagement in its optimal direction, thereby improving overall winding efficiency.

Inventive Principle:
Principle #1Segmentation

3Reliability

If unidirectional clutching with wedging is used, then one-direction rotation is achieved with reduced stresses, but the mechanism cannot handle both oscillation directions

Engineering Contradiction:
Improvemechanism longevityVSAvoiddirectional flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

Two unidirectional freewheel clutches are merged into a single automatic winding mechanism, with each clutch handling one direction of oscillation. This combination maintains the reliability benefits of unidirectional operation (reduced stresses and increased longevity) while achieving the adaptability of bidirectional winding capability through the coordinated operation of both clutches.

Inventive Principle:
Principle #5Merging (Combining)

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 enhances efficiency by reducing the braking and dead angles, leading to lower input forces and torques, thereby increasing the longevity of the watch movement and improving overall performance.

Implementation Method 1

The transmission member cooperates with the clutch member by means of intermittent wedging so as to drive the second movable part in a unidirectional rotary motion. The wedging employs a principle of clamping in one direction

Methodology Applied
Scientific EffectWedging: Wedge

Data Source

PatentEP3203326B1Timepiece conversion mechanism of a rotary motion with any amplitude and direction into a one-way motion
Publication Date: 2020.03.04 CARTIER INTERNATIONAL AG
  • EP3203326B1 patent drawingFigure 1
  • EP3203326B1 patent drawingFigure 2~3
  • EP3203326B1 patent drawingFigure 4~5

AI summary

Conversion mechanism intended for a watchmaking application, comprising a first moving part (3) driveable according to any rotary motion, a second moving part (5), and a transmission member (4) cooperating with the first and second moving parts (3, 5); the first moving part (3) comprising a plate (31) pivoting about an axis (33) and a guide member (32), the latter being configured to drive the transmission member (4) eccentrically with respect to the axis (33); the second moving part (5) comprising a clutch member (51); the transmission member (4) cooperating with the clutch member (51) by intermittent buttressing so as to drive the second moving part (5) according to a unidirectional rotary motion.