Calendar Drive Mechanism Preventing Indicator Racing

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Solution Overview

Problem

The existing date display mechanisms in timepieces are prone to indicator 'racing' due to inconsistent manual force during date correction, leading to desynchronization, which can only be restored by opening the timepiece, and existing solutions like using a ratchet and pins are complex and costly.

Innovation Solution

The drive mechanism employs a return spring to control the rocker's engagement with the date wheel, ensuring a consistent and adjustable force for date changes, eliminating the risk of indicator racing without additional parts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a pusher is used to manually correct the date, then date correction can be performed, but the inconsistent manual force causes indicator racing and desynchronization

Engineering Contradiction:
Improvedate correction capabilityVSAvoidindicator synchronization
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

A rocker arm is introduced as an intermediary between the pusher and the date wheel. The rocker arm converts the inconsistent pusher force into a controlled motion that engages and disengages the date wheel teeth systematically, preventing indicator racing while maintaining manual date correction capability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The mechanism transitions from a static direct-drive system to a dynamic system where the rocker arm oscillates between engaged and disengaged states. This dynamic behavior allows the system to absorb force variations and maintain reliable indicator synchronization during manual correction

Inventive Principle:
Principle #15Dynamics

2Reliability

If a ratchet and pins are added to prevent indicator racing, then reliability improves, but device complexity and cost increase

Engineering Contradiction:
Improveindicator synchronizationVSAvoidnumber of additional parts
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The rocker arm performs multiple functions: it acts as a force amplifier, a motion converter, and a locking mechanism. By making the rocker arm multi-functional, the patent eliminates the need for separate ratchet and pin components, reducing complexity while maintaining reliability

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

Solution Approach 2:

The patent combines the functions of force transmission, motion control, and indicator protection into a single rocker arm mechanism. This merging of functions replaces the need for multiple separate components (pusher, ratchet, pins), thereby reducing device complexity and cost

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 prevents indicator desynchronization during date changes, ensuring precise and synchronized date display without the need for additional components, and allows for instantaneous date transitions, unlike traditional mechanisms which take several minutes.

Implementation Method 1

by the effect of a return spring acting on the rocker

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP1960844B1Drive mechanism for a calendar display for a time piece
Publication Date: 2014.08.13 GLASHUTTER UHRENBETRIEB GMBH
  • EP1960844B1 patent drawingFigure 1
  • EP1960844B1 patent drawingFigure 2
  • EP1960844B1 patent drawingFigure 3

AI summary

A calendar date display comprises a ten-day pointer (2) and a unit pointer (1) driven by a program drive (8), which is provided with a calendar date display (9) whose toothing is engaged with the nose (15) of a lever (16) in such a way that a wheel is moved one step forward by one calendar number change. Between each calendar number change, the nose (15) is engaged between the first and second teeth (11, 12) of the wheel (9). At the time of the calendar number change, the nose (15) is disengaged from said first and second teeth (11, 12) in such a way that it is engaged between the second and third (12, 13) teeth of the wheel (9), thereby moving said wheel one step forward.