Mechanical Oscillator Frequency Correction via Elastic Blade Stiffness
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Solution Overview
Problem
Mechanical oscillators in timepieces face isochronism defects due to variations in motor torque, leading to deviations in oscillation amplitude and period, which existing correction devices fail to account for, especially due to frictional variations in the oscillator and gear train components.
Innovation Solution
A mechanical oscillator with a frequency correction device featuring adjustable elastic blades that alter their effective length and stiffness, allowing for inverse non-linearity in the return spring to compensate for torque variations, maintaining constant frequency across amplitude changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fusee device is used to compensate for motor torque variation, then the amplitude of oscillation can be regulated, but the device becomes difficult to miniaturize and cannot be applied in mechanical watches
Solution Approach 1:
The correction element is nested within the existing barrel spring assembly, with the correction element having a smaller radius than the barrel spring and being positioned concentrically. This allows the correction mechanism to be integrated into the existing structure without requiring additional space, enabling miniaturization while maintaining the amplitude regulation function.
Solution Approach 2:
A flexible correction element acts as an intermediary between the barrel spring and the oscillating system. This correction element transmits a portion of the motor torque to the oscillating system, allowing regulation of the driving force without requiring a complex fusee mechanism. The flexible nature of the correction element enables it to adapt to space constraints in mechanical watches.
2Measurement precision
If existing correction devices are used to compensate for motor torque variation, then frequency correction can be achieved, but variations due to friction in the oscillator and gear train are not accounted for
Solution Approach 1:
The correction element is designed to be flexible rather than rigid, allowing it to dynamically adapt to varying friction conditions in the oscillator and gear train. The flexibility enables the correction element to adjust its engagement and torque transmission characteristics based on real-time operating conditions, providing compensation for friction variations that rigid correction devices cannot address.
3Device complexity
If the barrel spring directly couples to the cogs of the dynamic chain, then the structure is simplified, but the variation in load spring torque modifies the amplitude and period of the oscillator
Solution Approach 1:
The torque transmission path is segmented by introducing a separate correction element that is coupled to the oscillating system. This segmentation allows the correction element to independently regulate the torque transmitted to the oscillating system, decoupling the amplitude and period stability from the variations in the main barrel spring torque. The correction element can be adjusted to provide the precise torque needed for stable oscillation regardless of the barrel spring's load state.
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 solution effectively compensates for isochronism defects by adjusting the frequency in response to amplitude variations, reducing deviations and maintaining accurate oscillation, even under varying motor torque conditions.
Implementation Method 1
the first of these elements comprising an elastic flexible blade fixed by one of its ends
Data Source
Figure 1
Figure 2~5
Figure 4
AI summary
The oscillator has an oscillatory system constituted of a balance (1) and a return spring (3). A frequency correction device (20) has flexible elastic straps (9, 10) that are supported on a T-shaped connection member or stop (8). The straps have ends connected to a fixation and adjusting interface (11) via pins (12, 13) using locking screws (15, 16), respectively. The interface is secured to a frame (4) by a screw (17), and the member or stop is directly fixed to the balance. The member or stop is pressed against free ends of the straps during a part of oscillation period.