Moon Phase Display Mechanism With Fractional Daily Jumps
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Solution Overview
Problem
Existing moon phase display mechanisms in timepieces suffer from inaccuracies due to a cumulative error that requires correction every few years, and jumping mechanisms introduce a daily 'display error' in the moon's position relative to the lunar orb, which complicates the display and is costly or bulky.
Innovation Solution
A jumping moon phase display mechanism that fractionates the daily step of the moon phase indicator, incrementing it multiple times a day to improve accuracy, using a cam-driven phase rocker and intermediate gears to achieve a lunar period of 29.53125 days with reduced daily error, and includes a quick-correction device for periodic adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a jumping moon phase display mechanism is used, then the mechanism is compact and inexpensive, but it introduces a daily display error in the moon's position relative to the lunar orb
Solution Approach 1:
The patent divides the single daily jump of the moon phase indicator into multiple smaller increments throughout the day. The cam mechanism has multiple drive fingers that activate the phase rocker at different times, fractionating the total angular displacement into discrete steps. This segmentation reduces the display error by distributing the movement across multiple smaller jumps rather than one large jump, while keeping the mechanism compact and mechanical.
2Measurement precision
If a trailing moon phase display mechanism is used, then the display accuracy is improved with real-time moon position, but the mechanism becomes complex and bulky
Solution Approach 1:
The patent uses periodic action by having the cam rotate once per day and present multiple drive fingers to the phase rocker at predetermined intervals. This creates multiple controlled jumps throughout the day, simulating the continuous motion of a trailing mechanism while maintaining the simplicity of a jumping mechanism. The periodic engagement of drive fingers provides frequent updates without requiring continuous mechanical connection.
3Measurement precision
If the moon phase indicator is incremented multiple times a day, then the display resolution is enhanced and daily error is reduced, but the mechanism requires more complex drive components
Solution Approach 1:
The patent introduces a cam as an intermediary component between the daily-driven gear and the phase rocker. The cam converts the single daily rotation into multiple controlled activations of the phase rocker through its profiled surface with multiple drive fingers. This intermediary mechanism efficiently translates one rotational input into multiple precise outputs without requiring complex direct driving of the phase indicator multiple times.
Solution Approach 2:
The cam mechanism is self-regulating as it rotates once per day, automatically presenting drive fingers to the phase rocker at the correct intervals without requiring external control. The geometry of the cam profile inherently controls the timing and magnitude of each increment, making the multi-step operation self-actuating from a single daily drive input.
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
The mechanism provides enhanced display resolution and accuracy, reducing daily errors to 6.1° by incrementing the moon phase indicator multiple times a day, while maintaining a compact design and allowing for user-friendly periodic corrections.
Implementation Method 1
a cam having an upper zone forming a drive finger, said cam being capable of being driven by the clockwork movement
Data Source
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AI summary
One aspect of the invention relates to a moon phase display mechanism (100) for a timepiece suitable for being powered by a timepiece movement (200) whose operation depends on the division of time, said moon phase display mechanism (200) comprising: a moon phase indicator (110) bearing at least one representation of the moon; a jumping drive mechanism (120) for the moon phase indicator (110) suitable for being powered by said timepiece movement (100) and for jumping the moon phase indicator (110);the moon phase display mechanism (100) being characterized in that the jumping drive mechanism (120) is configured to rotate said moon phase indicator (110) by n increments per day, n being greater than 1, each increment rotating the moon phase indicator (110) by an angle α corresponding to the rotation angle of one daily step divided by the number n of increments.;