Watch Oscillator Ferrule for Thickness and Assembly Control
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Solution Overview
Problem
Existing watch movement oscillators face challenges in reducing size without compromising simplicity, assembly reliability, or adjustability, particularly to accommodate additional mechanisms or ultra-thin designs.
Innovation Solution
The introduction of a ferrule interposed between the balance wheel and balance shaft allows precise control of the gap between the wheel and hairspring, reducing the oscillator's thickness while simplifying production and reducing the risk of balance shaft breakage, with a cylindrical barrel and shoulders for axial stops, and optional housing of the hairspring within the balance wheel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the balance wheel and hairspring are placed adjacent to each other to reduce oscillator thickness, then the size is reduced, but the risk of collision increases
Solution Approach 1:
The patent introduces a ferrule as an intermediary component positioned between the balance wheel and the balance shaft. This ferrule includes a shoulder that defines a stop, precisely controlling the axial gap between the balance wheel and hairspring. By using this intermediary element, the design achieves minimal spacing while maintaining a safe clearance to prevent collision, thus resolving the contradiction between reducing thickness and ensuring reliability.
2Strength
If the balance shaft is made of brittle material such as ceramic, then the aesthetic appearance and hardness are improved, but the risk of breakage during assembly increases
Solution Approach 1:
The patent incorporates a shoulder on the ferrule that defines a stop before the balance wheel can be fully axially pressed onto the balance shaft. This pre-defined stop cushions the assembly process by preventing excessive force from being applied to the brittle ceramic balance shaft, thereby significantly reducing the risk of breakage during assembly while still allowing the use of hard, aesthetically pleasing materials.
3Manufacturing precision
If multiple components are chased on the balance shaft (ferrule and balance), then the assembly precision is improved, but the complexity and risk of breakage increase
Solution Approach 1:
The patent merges the functions of the ferrule and balance wheel assembly by incorporating the stop-defining shoulder directly into the ferrule structure. This integration means that only the ferrule needs to be chased onto the balance shaft, rather than separately chasing both the ferrule and balance. This reduces the number of operations, simplifies the process, and decreases the cumulative risk of breakage while maintaining precise positioning through the integrated shoulder stop.
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3b
AI summary
The present invention relates to an oscillator (1) for a watch movement comprising a balance staff (6) mounted rotatably in a balance bridge (22) intended to be assembled to a frame element (60) of the watch movement, a balance (2) and a ferrule (8) integral with the balance staff (6), characterized in that the ferrule (8) is interposed between the balance (2) and the balance staff (6) to ensure the mounting of the balance (2) on the balance staff (6).