Annual Calendar Watch Mechanism Independent Date Month Correction
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Solution Overview
Problem
Existing annual calendar mechanisms for watches are inconvenient for quick and independent correction of date and month indications, often requiring simultaneous adjustment and leading to incorrect displays during transition periods.
Innovation Solution
An annual calendar mechanism with a kinematically disconnected date disc and month cam, except during month transitions, utilizing an instantaneous release mechanism for quasi-instantaneous correction, allowing independent and rapid adjustment of date and month indications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the date disc and month cam are kinematically connected to enable automatic month indication, then the calendar mechanism operates automatically, but the date and month cannot be corrected independently leading to inconvenience during manual adjustment
Solution Approach 1:
The patent divides the calendar mechanism into two independent subsystems: the date disc drive wheel set and the month cam drive wheel set. This segmentation allows each subsystem to be adjusted independently without affecting the other, resolving the contradiction between ease of operation and device complexity by making the correction process modular and independent.
Solution Approach 2:
The patent introduces an intermediary mechanism - the drive wheel set with selective engagement capability - that can choose to engage with either the date disc toothing or the month cam toothing but not both simultaneously. This intermediary structure enables independent correction by mediating between the two previously coupled systems.
2Productivity
If a second toothing is added to the date disc for month cam actuation, then automatic month correction is enabled, but the mechanism cannot be quickly corrected without phase shift risk
Solution Approach 1:
The patent makes the kinematic connection between the date disc and month cam dynamic rather than static. The drive wheel set can dynamically engage or disengage from either the date disc toothing or the month cam toothing based on correction needs. This dynamic capability allows quick correction of either element independently without risking phase shifts, as the connection is established only when needed.
Solution Approach 2:
The patent implements periodic selective engagement where the drive wheel set engages with the appropriate toothing only during correction operations. During normal operation, the automatic drive maintains the kinematic connection, but during quick correction, the user can temporarily engage the manual drive wheel set for rapid adjustment without affecting the other element.
3Measurement precision
If the date disc is driven continuously through one step per day, then the date indication is always current, but the transition period shows incorrect dates creating display errors
Solution Approach 1:
The patent enables the date disc to skip intermediate positions during quick correction. Instead of advancing one step at a time through incorrect dates, the user can rapidly rotate the date disc to the correct position using the manual drive wheel set. This skipping mechanism eliminates the period of incorrect display by rushing through the transition without stopping at wrong dates.
Solution Approach 2:
The patent allows preliminary positioning of the date disc before the actual month transition occurs. Users can anticipate the upcoming transition and pre-adjust the date disc to the correct position using the independent manual drive, so that when the automatic mechanism completes its cycle, the display is already accurate, preventing any period of incorrect indication.
Data Source
AI summary
The invention concerns an annual calendar mechanism for a timepiece including a date disc (16) to which are thirty one figures are affixed each corresponding to an indication of a day of the month provided with a first inner toothing (20) including thirty one teeth (20a), a date drive wheel set (32), said wheel set (32) including a finger (34) driving the date disc (16) through one step per day via one of the teeth (20a) of the first inner toothing (20) in order to control the date display, said date disc (16) including a second toothing (24), a correction drive wheel set (42) able to cooperate with the second toothing (24) to drive the date disc (16) through an additional step at the end of the months of less than thirty one days, and a month star wheel (54) arranged to be actuated at the end of each month and to complete one revolution per year, characterized in that in includes a month drive wheel set (52) provided for driving the month star wheel (54) at the end of each month, said drive wheel set (52) being connected, via a gear train (35, 56), to the date drive wheel set (32) and to the additional correction drive wheel set (42), said wheel set (52) occupying a first position in which it has no effect on the month star wheel (54), such that the kinematic chain between the date disc (16) and the month star wheel (54) is broken, and a second position that it occupies only at the moment when the change of month occurs and in which it actuates the month star wheel (54) so as to move it one step forward, such that a correction device (90) can act on the date disc (16) without any effect on the month star wheel (54) and vice versa.