Perpetual Date Cam Mechanism for Secular Year Correction
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Solution Overview
Problem
Existing perpetual calendar mechanisms in timepieces struggle to accurately account for the Gregorian calendar's secular and millennial corrections without requiring significant mechanical modifications or increased thickness.
Innovation Solution
A perpetual calendar display system that integrates a 12- or 48-month cam mechanism with a selectively adjustable stop to correct for leap years, century years, and millennial years, maintaining accuracy while minimizing part count and thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional perpetual calendar mechanism is used to track leap years, then the mechanism can handle basic 4-year cycles, but it cannot accurately account for Gregorian calendar secular corrections (century years not divisible by 400)
Solution Approach 1:
The mechanism divides the calendar correction function into separate modular components: a 12-month cam for basic monthly tracking, a 48-month cam for leap year cycles, and a secular correction cam for Gregorian century rules. Each cam operates independently at different rotational speeds, allowing complex calendar calculations to be broken down into manageable segments that can be manufactured and assembled separately.
Solution Approach 2:
The patent implements nested cam structures where smaller correction cams are positioned within or alongside larger cam mechanisms. The secular correction cam integrates with the existing 48-month cam structure, with correction pins extending from the secular cam to interact with the date advancement mechanism. This nesting allows multiple correction functions to share physical space and mechanical pathways, reducing overall device complexity while maintaining accuracy.
2Measurement precision
If additional correction mechanisms are added to achieve secular and millennial corrections, then calendar accuracy improves, but the thickness of the mechanism increases
Solution Approach 1:
The patent utilizes the thickness dimension of existing cam components to house correction elements. Instead of adding lateral extensions that would increase the overall footprint, the secular and millennial correction pins are positioned within the thickness of the cam structure, leveraging the existing Z-axis space. The correction pins extend radially from the cam circumference, using the cam's own thickness as the mounting substrate, thereby avoiding additional thickness while enabling secular corrections.
Solution Approach 2:
The patent combines multiple correction functions into unified cam structures. The secular correction cam and millennial correction cam are integrated with the existing 48-month cam assembly, sharing common mounting surfaces and mechanical pathways. The correction pins from different cams work in coordination through the same date advancement mechanism, merging multiple correction functions into a single integrated system that avoids additive thickness from separate correction mechanisms.
3Adaptability or versatility
If the stop distance is made adjustable in the thickness of the cam, then secular corrections can be made, but the manufacturing complexity increases
Solution Approach 1:
The patent implements adjustability through parameter variation in the stop position relative to the cam axis. The distance of the stop from the rotation axis can be selectively changed in discrete steps (e.g., 12 or 48 positions around the circumference) to account for different Gregorian calendar century rules. This is achieved through selectable pin positions or adjustable stop mechanisms that can be set during assembly or adjustment, allowing the same physical mechanism to adapt to different secular correction requirements without redesigning the entire cam structure.
Solution Approach 2:
The stop mechanism incorporates dynamic adjustability, allowing the stop position to be changed based on the specific secular correction requirements. Rather than a fixed stop, the mechanism allows selection among multiple predetermined positions, enabling the same cam assembly to serve different calendar correction needs. This dynamic capability is implemented through selectable engagement points or adjustable stop components that can be repositioned without requiring complex active control systems.
Data Source
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AI summary
The invention relates to a system (1) for displaying the perpetual date of a Gregorian calendar comprising at least one date display and a counting device (9) intended to selectively increment the date display at the end of the month according to a number of predetermined additional units, depending on the number of days in the month. According to the invention, the display system (1) comprises a 12- or 48-month 5 cam mechanism (17) and the counting device is arranged to form an abutment (19) used for counting leap years, the distance of which relative to an axis (A) of rotation of the 12- or 48- month cam (17) is selectively adjustable in the thickness of the 12- or 48- month cam (17) so as to provide secular-year corrections to the Gregorian calendar.