Watch Date Correction Mechanism with Selective Lever Engagement

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Solution Overview

Problem

Conventional mechanical watches face issues with date correction mechanisms that can weaken the watch's sealing and limit decoration options, and existing solutions risk breaking date driving arms during midnight corrections or require specific tooth cutting for jamming prevention.

Innovation Solution

A watch movement design featuring a control stem with a first rocker, a second rocker, and a third lever that kinematically links to a date correction mechanism, allowing unidirectional date correction without a case opening, using a positioning pin, return spring, and a date correction wheel to manage meshing positions and prevent jamming.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a push-button is provided on the watch case for rapid date correction, then the date can be corrected rapidly, but an opening in the case is required which weakens the sealing and limits decoration choices

Engineering Contradiction:
Improvedate correction speedVSAvoidcase sealing
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent combines the date correction function with the existing control stem located at 3 o'clock, eliminating the need for a separate push-button. The control stem is configured to occupy three positions including a date correction position, integrating multiple functions into a single component that does not require additional case openings, thus maintaining case sealing integrity while enabling rapid date correction.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of operation

If the date correction mechanism is in permanent mesh with the date ring, then the date can be corrected in both directions, but there is a risk of breaking the date driving arm during midnight corrections

Engineering Contradiction:
Improvedate correction flexibilityVSAvoiddate mechanism durability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent implements a dynamic meshing system where the date correction mechanism (fourth correction wheel) can be selectively engaged or disengaged from the date ring based on the control stem position. In the date correction position, the mechanism is in mesh for bidirectional correction; in other positions, it is disengaged to prevent damage during midnight corrections, allowing the mechanism to adapt its state to operational requirements.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If the control stem is kinematically linked to both the time display and date correction mechanisms simultaneously, then all functions are accessible, but jamming occurs between the second time-setting wheel and date correction mechanism

Engineering Contradiction:
Improvecontrol stem functionalityVSAvoidmechanism operation smoothness
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent segments the control stem's operational paths by introducing a positioning pin on the first rocker that selectively engages with different positions on the second rocker. This segmentation ensures that when the control stem is in the time-setting position, the first drive wheel is kinematically linked only to the second time-setting wheel, while in the date correction position, it is linked only to the date correction mechanism, preventing simultaneous engagement and potential jamming.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3144743B1Clock movement comprising a mechanism for correcting the date
Publication Date: 2018.03.14 ETA SA MFG HORLOGERE SUISSE
  • EP3144743B1 patent drawingFigure 1
  • EP3144743B1 patent drawingFigure 2
  • EP3144743B1 patent drawingFigure 3

AI summary

A timepiece movement including a first lever bearing a first drive wheel, a second lever bearing a second wheel for time setting, and a third lever bearing a date correction mechanism. The third lever is mounted to pivot on the second lever and arranged to move between a meshing position, in which the date correction mechanism cooperates with the date display mechanism, and a retraction position, in which the date correction mechanism is disconnected from the date display mechanism. The first and second levers are arranged to occupy at least one date correction position, in which the first drive wheel is kinematically connected to the date correction mechanism and is not kinematically connected to the second wheel for time setting, and a time setting position, in which the first drive wheel is kinematically connected to the second wheel for time setting and is not kinematically connected to the date correction mechanism, wherein the position of the second lever is modified by cooperation between the first lever and the second lever.