Dual Jumper Mechanism for Large Date Calendar Display
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Solution Overview
Problem
Conventional large date calendar display mechanisms in timepieces face challenges in maintaining accurate positioning of the units component of the date indicator during the transition from '31' of a month to '01' of the following month, leading to potential misalignment and mechanism blocking due to the temporary uncoupling from the horological movement.
Innovation Solution
A dual jumper mechanism is introduced, which pivots about an axis and engages with both the units indicator ring and the pinion, ensuring continuous correct positioning and preventing the units indicator from pivoting during the transition period by being elastically held in place, thus maintaining accurate indexing and preventing misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wheel is made devoid of teeth at one point to prevent driving the pinion during transition from 31 to 01, then the units indicator can remain still during the transition, but the pinion loses continuous positioning and may become misaligned or block the mechanism
Solution Approach 1:
A cam mechanism is introduced as an intermediary element between the wheel and the pinion. The cam has a specific profile that interacts with a follower on the pinion to control its positioning. During normal operation, the cam maintains the pinion in the correct angular position. During the transition from date 31 to 01, the cam profile allows the pinion to be temporarily disengaged or held in a neutral position without requiring the wheel to have missing teeth, thus solving the positioning problem while maintaining wheel integrity.
Solution Approach 2:
The system transitions from a static tooth engagement mechanism to a dynamic cam-based positioning system. The cam profile is designed to provide continuous guidance during normal operation and automatic release or neutral positioning during the transition period. This dynamic approach allows the pinion to smoothly transition between engaged and disengaged states without requiring complex intervention mechanisms.
2Ease of manufacture
If a single date ring with indications 1-31 is used, then the mechanism comprises fewer parts and is more cost-effective, but only a small angular sector is available making date indications hard to read
Solution Approach 1:
The date display is segmented into two separate components: a units indicator ring showing digits 0-9 and a tens indicator showing digits 0-3. This segmentation allows each ring to have sufficient angular space for large, readable numerals while maintaining a compact overall structure. The two indicators work together to display dates 01-31, combining simplicity of construction with high readability.
3Reliability
If the units indicator ring must remain still during transition from 31 to 01, then accurate date display is maintained, but the kinematic chain must be interrupted requiring additional positioning mechanisms
Solution Approach 1:
The cam mechanism serves as an intermediary that mediates between the continuous rotation of the wheel and the requirement for the pinion to remain stationary during transition. The cam profile is designed to maintain engagement during normal operation and automatically provide the necessary disengagement or holding action during the transition from date 31 to 01, eliminating the need for complex intervention mechanisms.
Solution Approach 2:
The cam mechanism is designed to automatically control the pinion positioning based on the wheel's rotation position. The cam profile inherently provides the correct guidance and release timing without requiring external control mechanisms. The system serves itself by using the wheel's own motion to drive the cam, which in turn controls the pinion positioning, eliminating the need for separate control systems.
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 dual jumper mechanism guarantees the correct positioning of the units component of the date indicator during the transition, ensuring accurate date display and preventing mechanism blocking, thereby maintaining the reliability and aesthetics of the timepiece.
Implementation Method 1
the dual jumper being elastically held engaged with the first date indicator and with the pinion
Data Source
AI summary
A date calendar display mechanism driven via a kinematic chain by a horological movement of a timepiece. A first and second date indicators, the first date indicator remaining still during a 24-hour period separating the passage from the last day of a month having 31 days to the end of the first day of the following month, the kinematic chain including a wheel continuously engaged with the horological movement and having a toothing via which the wheel meshes with a pinion which contributes to driving the first indicator, the wheel being, at one point, devoid of teeth such that, during the above 24-hour period, the wheel does not mesh with the pinion and remains still. A dual jumper pivots about an axis with a first beak via which it is engaged with a toothing of the first date indicator and, at a second beak via which it is engaged with a toothing of the pinion, the dual jumper being elastically held engaged with the first date indicator and with the pinion.