Timepiece Calendar Jump Mechanism for Low-Torque Date Changes
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Solution Overview
Problem
Existing timepiece calendar systems face issues with energy inefficiency, torque fluctuations, and bulkiness, particularly in implementing instantaneous-jump drive devices for annual, semi-perpetual, or perpetual calendars, leading to potential drops in amplitude at the oscillator and premature wear.
Innovation Solution
A timepiece calendar system with a desmodromic system and separate drive mobiles, utilizing a first drive finger and tooth that can displace the date mobile through multiple steps with a single action, combined with a calendar cam and spring-lever for instantaneous jumps, optimizing energy use and reducing bulkiness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a single drive mobile with elastic lever is used for instantaneous date jump, then the date can change instantaneously irrespective of number of jumps, but abrupt torque variations cause drops in oscillator amplitude
Solution Approach 1:
The drive system is divided into two separate drive mobiles instead of one. The first drive mobile (with fixed axis) handles the primary date advancement, while the second drive mobile (with displaceable axis) provides supplementary jumps at month ends. This segmentation distributes the driving action across multiple components, smoothing torque delivery to the oscillator while still achieving instantaneous date changes.
Solution Approach 2:
The second drive mobile is designed with a displaceable axis of rotation that moves relative to the frame during operation. This dynamic positioning allows the drive finger to optimally engage with date wheel teeth at different phases of the month, enabling precise control over when supplementary jumps occur without causing torque shocks to the oscillator.
2Adaptability or versatility
If a month-programming cam disposed coaxially with the second mobile is used, then the calendar system can handle months with different days, but the cam is particularly bulky leaving little area for calendar cam and elastic lever
Solution Approach 1:
Instead of positioning the month-programming cam coaxially with the second drive mobile (occupying radial space), the cam is arranged at a different location in the mechanism. The drive finger of the second mobile is mounted to be displaceable relative to this cam, creating a spatial arrangement that reduces the overall footprint of the drive device while maintaining full calendar functionality.
Solution Approach 2:
The month-programming cam is integrated into the existing drive mechanism structure rather than being a separate bulky component. The cam profile is designed to work in conjunction with the displaceable drive finger, allowing the finger to follow the cam's contour during its displacement cycle, effectively nesting the programming function within the drive mechanism's operational envelope.
3Duration of action of moving object
If the second finger is elastically returned against the month-programming cam under the effect of a return spring, then the finger can reset for the next cycle, but this leads to superfluous energy consumption and torque fluctuations throughout the day
Solution Approach 1:
The return spring mechanism is removed from the system. Instead of using elastic force to return the drive finger to its initial position, the invention uses a dedicated reset mobile (the third drive mobile) that positively drives the second drive mobile's axis back to its starting position. This extraction of the spring eliminates continuous energy consumption and torque fluctuations associated with elastic deformation and release.
Solution Approach 2:
The drive finger system is designed to be self-resetting through the kinematic connection between the two drive mobiles. As the first drive mobile completes its rotation, it automatically resets the second drive mobile's displaceable axis to its initial position through the established mechanical linkage, eliminating the need for separate reset springs or motors.
4Productivity
If the drive finger performs a complete rotation around the month-programming cam every day, then the calendar system advances through all months, but this leads to premature wear of the drive device
Solution Approach 1:
The month-programming cam is designed with a profile that allows the drive finger to skip over certain portions of its circumference on most days. The finger only makes significant contact and drives the cam when specific conditions are met (at month boundaries), rather than continuously rubbing against the cam surface throughout the entire rotation. This skipping action dramatically reduces wear on both the finger and cam.
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 system achieves efficient energy use, minimizes torque fluctuations, and enhances the calendar's compactness, ensuring smooth operation and reduced wear, compatible with various calendar types.
Implementation Method 1
incorporating a spring-lever and calendar cam for instantaneous operation
Data Source
AI summary
The timepiece calendar system (200) includes a date mobile (4) displaceable step by step relative to a frame (199); a first drive finger (21) for driving the date mobile (4); a first tooth (51) for driving the date mobile (4), the first tooth (51) being mounted on the date mobile (4) so as to be displaceable between a deactivated, or retracted, position and an activated, or drive, position; an activation system (6, 7) for activating the first tooth (51); the first drive finger (21) and the first tooth (51) being arranged such that a single action of the first drive finger (21) on the first tooth (51) displaces the date mobile (4) through n steps, with n being an integer of any value between 1 and N, N being an integer with N>1, depending on the moment when the first tooth (51) is activated by the activation system (6, 7).