Watch Oscillator Assembly Using Predicted Spring Stiffness
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Solution Overview
Problem
Existing methods for assembling watch oscillators are complex, costly, and require time-consuming stiffness measurements for each elastic restoring element to ensure the desired frequency, lacking simplicity and reliability.
Innovation Solution
A method involving lithography and machining to create a stiffness classification system on a reference wafer, measuring a subset of elastic restoring elements, predicting the stiffness of unmeasured elements, and pairing them with inertial elements to achieve the desired oscillation frequency, using vibratory excitation and laser vibrometry for non-contact measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If stiffness measurements are performed on each elastic restoring element, then frequency accuracy is ensured, but assembly time and cost increase
Solution Approach 1:
The patent applies partial measurement by measuring stiffness of only a subset of elastic restoring elements (e.g., one per batch) rather than each individual element. This partial action achieves sufficient frequency control while dramatically reducing measurement time and assembly complexity.
Solution Approach 2:
The patent implements preliminary classification by pre-grouping elastic restoring elements into stiffness categories before assembly. This preliminary action allows faster matching with inertial elements during assembly, eliminating the need for individual measurements while ensuring frequency accuracy.
2Measurement precision
If stiffness measurements are performed on each elastic restoring element, then frequency control is ensured, but manufacturing cost increases
Solution Approach 1:
The patent reduces manufacturing cost by performing stiffness measurements on only a partial subset of elastic restoring elements rather than each element. This partial measurement approach maintains frequency control accuracy while significantly lowering measurement and assembly costs.
Solution Approach 2:
The patent uses stiffness measurements from measured elements as proxies or copies to represent unmeasured elements within the same batch. This copying approach allows frequency control without direct measurement of each element, reducing manufacturing overhead.
3Measurement precision
If all elastic restoring elements are measured for stiffness, then classification accuracy is improved, but measurement time increases
Solution Approach 1:
The patent achieves sufficient classification accuracy by measuring only a partial subset of elastic restoring elements. The measured elements provide enough statistical information to classify the entire batch, eliminating the time-consuming measurement of every element while maintaining classification reliability.
Solution Approach 2:
The patent performs preliminary stiffness measurements on a subset of elements to establish classification criteria before assembling the remaining unmeasured elements. This preliminary action creates a reference framework that enables accurate classification without measuring every element.
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
Enables faster, less expensive, and more reliable assembly of watch oscillators with accurate frequency control by reducing the need for extensive stiffness measurements, ensuring precise classification and coupling of elastic restoring elements.
Implementation Method 1
an elastic restoring element (for example, a balance spring), and in particular, the present invention relates to a method of assembling a watch oscillator in which a stiffness of the elastic restoring element is predicted or deduced
Implementation Method 2
an inertial element (for example, a balance wheel) and an elastic restoring element (for example, a balance spring)
Data Source
Figure 1~2
Figure 3~4
AI summary
A method for assembling a clock oscillator, comprising at least the steps of: - (S1) manufacturing a plurality of elastic return springs (20) in a reference plate (100), - (S2) measuring at least one stiffness of at least one elastic return spring (20) and at least one stiffness of at most a predetermined quantity of the elastic return springs (20) manufactured in the reference plate (100), - (S3) deducing a stiffness of at least some of the unmeasured elastic return springs (20) from the reference plate (100), - (S4) performing a stiffness ranking of the manufactured unmeasured elastic return springs (20) and/or providing a pairing of the unmeasured elastic return springs (20) with an inertial element (10) of suitable inertia, to allow each manufactured elastic return spring (20) to be assembled with an inertial element (10).