Watch Power Reserve Display via Stepwise Disc and Reduction Gear

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Solution Overview

Problem

Current power reserve display mechanisms in watchmaking lack precision and originality, failing to accurately represent the energy stored and consumed by the barrel and oscillating weight.

Innovation Solution

A power reserve display mechanism featuring a disc with digits connected to a reduction gear system, where the disc advances by one step for each turn of the oscillating mass, allowing for precise display from 0 to 999 and serving as a tachometer for bidirectional automatic winding systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional needle-based power reserve display is used, then the display mechanism is simple, but the measurement precision is insufficient

Engineering Contradiction:
Improvepower reserve display precisionVSAvoiddisplay mechanism complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The display mechanism is segmented into multiple digits (units, tens, hundreds) that can independently display different values. Each digit is driven by a separate gear train connected to the differential, allowing precise representation of power reserve levels through discrete numerical segments rather than a continuous needle.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A reduction gear mechanism serves as an intermediary between the differential output and the display digits. This intermediary component translates the continuous rotational motion from the differential into discrete stepwise movements of the digits, enabling precise power reserve indication while managing the complexity through a standardized transmission interface.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of information

If the display shows only barrel energy, then the mechanism is simple, but the information completeness is insufficient

Engineering Contradiction:
Improveenergy information completenessVSAvoiddifferential mechanism complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The differential mechanism performs multiple functions simultaneously: it calculates power reserve based on barrel energy, tracks oscillating weight revolutions, and drives the digital display. This multi-functional approach consolidates several measurement and display functions into a single integrated mechanism, reducing overall system complexity while providing comprehensive energy information.

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

Solution Approach 2:

The patent merges the power reserve calculation function with the oscillating weight tachometer function into a single differential-based display system. By combining these functions, the mechanism provides complete energy information (both stored energy and winding activity) without requiring separate mechanisms, thus managing complexity through functional integration.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If the disc advances continuously, then the display is smooth, but the readability of individual steps is reduced

Engineering Contradiction:
Improvepower reserve reading precisionVSAvoiddisplay readability
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The display digits advance in periodic steps rather than continuously, with each digit changing position at discrete intervals corresponding to specific power reserve thresholds. This periodic action creates distinct, easily readable positions for each digit while maintaining precise measurement capability, as the stepwise movement allows clear visual distinction between different power reserve levels.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP2352068B1Mechanism for displaying the running reserve
Publication Date: 2012.12.12 JOUVENOT FREDERIC
  • EP2352068B1 patent drawingFigure 1
  • EP2352068B1 patent drawingFigure 2
  • EP2352068B1 patent drawingFigure 3

AI summary

The mechanism has a display system comprising one or more disks (40) provided with digits for displaying numbers between a minimum number and a maximum number. The disk is connected to an output of a differential (22) through a reduction train (26) such that the display system displays the minimum number when a barrel is empty and the maximum number when the barrel is maximally loaded. The reduction train and an automatic winding system are arranged such that the disk advances by a pitch at a time when an oscillating mass performs revolution.