Perpetual Calendar Leap Year Mechanism With Low-Energy Gear Reduction
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Solution Overview
Problem
Perpetual calendar display mechanisms in watches are complex to manufacture and consume excessive energy, particularly in leap year indication systems.
Innovation Solution
A leap year display mechanism for a perpetual calendar watch movement featuring a drive element, transmission star, and reduction gear system that simplifies design and reduces energy consumption, utilizing a roller display with a reduction gear ratio of one-eighth turn per year.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional perpetual calendar display mechanism is used to display leap years, then the date display adapts automatically to month lengths and leap years, but the mechanism becomes complex to manufacture and assemble
Solution Approach 1:
The mechanism is divided into separate functional modules: a month wheel set for tracking months, a drive element for power transmission, a transmission star for leap year tracking, and a reduction gear train for speed adjustment. This segmentation allows each component to be manufactured and assembled independently, reducing overall manufacturing complexity while maintaining automatic adaptation functionality.
Solution Approach 2:
The month wheel set serves multiple functions: it tracks the current month, drives the leap year display mechanism through the drive element, and provides the rotational motion that powers the entire system. This multi-functionality reduces the need for separate dedicated components, simplifying the overall mechanism.
2Adaptability or versatility
If a traditional perpetual calendar display mechanism is used to display leap years, then the date display adapts automatically to month lengths and leap years, but the mechanism consumes a lot of energy
Solution Approach 1:
The mechanism uses periodic monthly rotations of the month wheel set to advance the leap year display by one step each month. This periodic action synchronized with the lunar calendar cycle allows the system to track leap years efficiently without requiring continuous energy input, as the display only updates at appropriate intervals rather than continuously.
Solution Approach 2:
The reduction gear train acts as an intermediary between the monthly-driven transmission star and the leap year display. It converts the monthly rotational input into the appropriate slower rotation of the leap year display, which completes a full cycle every four years. This intermediary mechanism efficiently transmits and transforms energy without requiring additional power sources.
3Volume of moving object
If a roller display is used for leap year indication, then the display is compact and suitable for watch movements, but the mechanism requires precise angular positioning
Solution Approach 1:
The roller display mechanism includes an automatic positioning system where a pawl and ratchet mechanism engage with the roller's circumference to automatically index it to the correct angular position after each monthly advancement. This self-positioning feature eliminates the need for complex external positioning mechanisms, maintaining compactness while ensuring precise angular alignment through the inherent mechanical geometry of the roller and its engagement elements.
Data Source
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AI summary
The invention relates to a leap year display mechanism (10) of a perpetual calendar display watch movement comprising: - a drive element (21) connected to a month wheel (20) driven in rotation by one step per month, - a transmission star (30) intended to be fixed to a structure of the watch movement, arranged on the stroke of the drive element (21) so as to be driven in rotation by the latter when the month wheel (20) makes a complete revolution, - a leap year display (40) connected to the transmission star (30) by means of a reduction gear (32) so that at each revolution made by the month wheel (20) the leap year display (40) is driven in rotation by one step.