Retrograde Chronograph Split-Seconds Hand Readability
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Solution Overview
Problem
Conventional chronograph mechanisms with retrograde displays are complex and difficult to develop, often resulting in reduced readability due to multiple hands converging at the center of the watch dial, and existing solutions either rely on electronic movements or do not accurately represent retrograde movements for fractional seconds.
Innovation Solution
A chronograph mechanism featuring a split-seconds mobile with a retrograde display, utilizing a disengageable indexing device and a retrograde drive system that includes kinematic connections between the split-seconds counter and chronograph counter, allowing the seconds display member to move along a sector less than 360 degrees, enhancing readability by potentially arranging hands in a superimposed or separate configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple display members are arranged coaxially at the center of the dial, then all time units can be displayed in one location, but readability deteriorates due to hands converging and overlapping
Solution Approach 1:
The patent introduces a retrograde movement dimension for the split-seconds hand, allowing it to traverse a limited angular sector (typically 180 degrees) backward and forward, rather than rotating continuously in one direction. This dimensional change in movement pattern enables the hand to occupy different spatial positions during operation, reducing overlap with other hands and improving readability while maintaining coaxial arrangement for compactness
2Ease of manufacture
If a retrograde display mechanism is implemented, then readability improves by reducing hand overlap, but device complexity increases due to additional mechanical components
Solution Approach 1:
The patent merges the retrograde drive mechanism with the existing chronograph counter mechanism by establishing a direct kinematic connection between the split-seconds counter and the retrograde display mobile. The indexing device that normally synchronizes the split-seconds hand with the chronograph seconds hand is repurposed to also control the retrograde movement, eliminating the need for separate drive trains and reducing overall mechanical complexity
Solution Approach 2:
The indexing device serves dual functions: it maintains the traditional split-seconds functionality (allowing the split-seconds hand to be stopped independently) and simultaneously controls the retrograde display movement. This multi-functionality reduces the number of dedicated components needed and simplifies the overall mechanism while achieving both split-seconds measurement and retrograde display
3Measurement precision
If split-seconds functionality is added to enable intermediate time measurement, then measurement precision improves, but device complexity increases due to additional display members
Solution Approach 1:
The patent combines the split-seconds display function with the retrograde display mechanism into a single integrated system. The split-seconds hand serves dual purposes: it displays intermediate time measurements with high precision and simultaneously provides the retrograde visual indication. This merging eliminates the need for separate display elements for each function, reducing overall complexity while maintaining measurement precision
Data Source
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AI summary
Retrograde chronograph mechanism, for watch movement (1), intended to ensure, on demand, the retrograde drive of a first display element (38) of a unit of a measured time, preferably seconds of a measured time, the mechanism also comprising a split-seconds mobile (84) intended to carry a second display element (86) of the same unit of an intermediate measured time, a split-seconds counter connected to the chronograph counter (8) via a disengageable indexing device (62, 64), a retrograde drive device for the split-seconds mobile (84) having a kinematic link with the split-seconds counter, and a locking device (66, 68) for the split-seconds counter to allow the display of the intermediate measured time.