Clock Movement With Pivoting Date Correction Rocker for Midnight Protection

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Solution Overview

Problem

Existing mechanical watch mechanisms risk breaking a date drive arm during midnight date corrections and involuntarily change the date during time adjustments, necessitating separate corrections.

Innovation Solution

A watch movement with a control stem, winding mechanism, and date/time display mechanisms, featuring a first lever connected to the control stem, a second lever for date correction, and a third lever to lock the second lever in the time-setting position, preventing date changes during time corrections, using a sliding pinion and levers with limited angular travel and friction means.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the date correction mechanism is permanently meshed with the date ring, then date correction can be performed in both directions, but the risk of breaking the date drive arm increases during midnight corrections

Engineering Contradiction:
Improvedate correction operationVSAvoiddate drive arm durability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies the dynamics principle by making the date correction mechanism movable rather than fixed. The second lever pivots between a meshing position (where the date correction mechanism engages with the date ring) and a retracted position (where it disengages). This dynamic positioning allows the mechanism to be permanently meshed during normal operation for easy correction, while retracting during midnight to prevent breaking the date drive arm.

Inventive Principle:
Principle #15Dynamics

2Productivity

If the control stem is connected to both time-setting and date correction mechanisms, then rapid correction is possible, but the date changes involuntarily during time adjustments

Engineering Contradiction:
Improvecorrection speedVSAvoidcorrection precision
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The patent applies segmentation by dividing the correction functions into separate operational modes. The control stem can occupy distinct positions: one for time-setting only (where the third lever locks the second lever, preventing date correction) and another for date correction only (where the time-setting mechanism is disengaged). This segmentation prevents involuntary date changes during time adjustments while maintaining rapid correction capability.

Inventive Principle:
Principle #1Segmentation

3Duration of action of moving object

If the date correction mechanism remains engaged with the date display mechanism, then continuous correction is possible, but mechanical wear increases

Engineering Contradiction:
Improvecorrection continuityVSAvoidmechanical wear
Core Design Contradiction:
Duration of action of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent applies periodic action by engaging and disengaging the date correction mechanism at specific intervals. The mechanism is engaged during normal date correction operations and disengaged during midnight automatic corrections and time-setting operations. This periodic engagement pattern maintains correction continuity when needed while reducing mechanical wear by avoiding constant engagement.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP4375763B1Clock movement comprising a mechanism for correcting a display
Publication Date: 2025.09.10 ETA SA MFG HORLOGERE SUISSE
  • EP4375763B1 patent drawingFigure 1
  • EP4375763B1 patent drawingFigure 2
  • EP4375763B1 patent drawingFigure 3

AI summary

The invention relates to a watch movement comprising a control rod (1), a movement winding mechanism, a date display mechanism and a time display mechanism, the watch movement comprising a first rocker (10) carrying a drive wheel (11) capable of being kinematically linked to the control rod (1), and carrying at least one time-setting wheel (12) arranged to cooperate with the time display mechanism and capable of being kinematically linked to the drive wheel (11), and a second rocker (20) carrying a date correction mechanism capable of being kinematically linked to the drive wheel (11) as well as to the date display mechanism,the second rocker (20) being pivotally mounted on the first rocker (10) and arranged to move between an engagement position in which the date correction mechanism cooperates with the date display mechanism and a disengagement position in which the date correction mechanism is disconnected from the date display mechanism, and the control rod (1) and the first (10) and second (20) rockers are arranged to occupy three positions.