Watch Resonator Return Spring Stiffness Control
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Solution Overview
Problem
Existing processes for manufacturing recall springs for watchmaking resonators face challenges in achieving precise stiffness control without altering thermal characteristics, leading to inefficiencies and complexities in frequency regulation.
Innovation Solution
A process involving the formation of recall springs with dimensions lower than required for a predetermined stiffness, followed by the deposition of a calculated oxide thickness at low temperature (not exceeding 500 °C) to achieve the desired stiffness without modifying thermal characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If material is removed from the balance spring to adjust stiffness, then manufacturing precision is improved, but productivity deteriorates due to uneconomical material removal
Solution Approach 1:
The patent forms the balance spring with dimensions smaller than the final required dimensions before stiffness adjustment. This preliminary action allows subsequent oxide deposition to add the necessary material thickness to achieve the target stiffness, avoiding the need to remove material and improving manufacturing efficiency
2Manufacturing precision
If material is added to the balance spring to adjust stiffness, then manufacturing precision is improved, but device complexity increases due to modification of thermal coefficients
Solution Approach 1:
The patent applies oxide deposition only to specific regions of the balance spring where stiffness adjustment is needed, rather than uniformly treating the entire spring. This localized approach allows precise stiffness control while minimizing interference with thermal compensation properties of the overall resonator system
3Reliability
If thermal oxidation is performed to compensate for thermal variations, then reliability is improved, but manufacturing precision deteriorates due to disturbance of thermal coefficients
Solution Approach 1:
The patent separates the stiffness adjustment function from the thermal compensation function into distinct process steps. First, the balance spring is formed with preliminary dimensions, then oxide is deposited to achieve target stiffness, and finally thermal compensation is applied. This segmentation allows each function to be optimized independently without interfering with the other
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
This approach allows for precise adjustment of recall spring stiffness independently of thermal compensation, simplifying the process and ensuring reliable frequency regulation of watchmaking resonators.
Implementation Method 1
deposit said thickness of oxide on the return spring at a temperature not exceeding 500°C so that the return spring has the predetermined stiffness
Implementation Method 2
an inertial element (balance wheel) oscillates under the action of an escapement, which imparts impulses of mechanical energy to it
Data Source
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AI summary
The invention, according to a first embodiment, proposes a method for manufacturing a return spring for a watch resonator, comprising the following steps: a) forming a return spring with dimensions smaller than those required for the return spring to have a predetermined stiffness; b) determining the stiffness of the return spring; c) based on the result of step b) calculating the thickness of oxide to be deposited on the return spring to achieve the predetermined stiffness; d) depositing said thickness of oxide on the return spring at a temperature not exceeding 500°C so that the return spring has the predetermined stiffness. Two other embodiments, also involving oxide deposition at a temperature not exceeding 500°C, are also proposed.