Hairspring Stud Holder Assembly with Nested Needle Screw
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Solution Overview
Problem
The existing assembly for fixing the outer end of the hairspring in a balance-spring device is cumbersome and prone to errors due to restricted access and small dimensions, often resulting in the detachment or loss of components during assembly and adjustment.
Innovation Solution
A novel assembly featuring a needle-tipped screw with an eyebolt housing and a convex attachment channel, allowing for precise positioning and adjustment of the hairspring's active length, with an anti-friction pad for smooth sliding, and a needle integrated into the screw body to prevent loss of components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional stud holder with tightening screw is used to fix the hairspring outer end, then the hairspring can be secured, but the assembly and adjustment operations become delicate and complex due to restricted access and small dimensions
Solution Approach 1:
The tightening screw is integrated within the stud holder body, with the screw head recessed into the holder. This nesting arrangement reduces the overall profile and allows the assembly to fit in restricted spaces while maintaining the fixation function, thereby improving ease of operation without compromising reliability
Solution Approach 2:
The stud holder combines multiple functions into a single integrated component: it houses the stud for hairspring engagement, contains the tightening screw for securing the hairspring, and provides the structural support for the entire assembly. This merging simplifies the manipulation required during assembly and adjustment
2Reliability
If conventional separate components (tightening screw and stud carrier) are used, then the hairspring can be fixed, but the components may become detached or lost during manipulation such as adjustment
Solution Approach 1:
The tightening screw is integrated within the stud holder body, forming a single assembled unit. This reduces the number of separate components that could potentially become detached or lost during manipulation, while maintaining the secure fixation function through the integrated screw-stud holder connection
Solution Approach 2:
The screw is nested within the stud holder with its head recessed into the holder body. This nested configuration ensures that the screw remains contained within the holder structure during manipulation, preventing detachment and loss while maintaining the fixation mechanism
3Device complexity
If a conventional flat or simple channel is used for hairspring attachment, then the structure is simple, but the adjustment of active length precision is limited
Solution Approach 1:
The channel features a convex portion with a specific radius of curvature that corresponds to the hairspring geometry. This localized geometric feature provides precise positioning and control of the hairspring active length, achieving high adjustment precision without requiring complex overall channel structures
Solution Approach 2:
The channel includes a convex portion with a radius of curvature matched to the hairspring curvature. This curved geometry enables precise engagement and adjustment of the hairspring active length by providing a geometrically defined contact point, achieving high precision without complex mechanisms
Data Source
Figure 1~2
AI summary
Assembly for securing the outer end of the balance spring (1) of a balance-spring device for a timepiece, comprising a stud holder (2) for housing a stud (10) against which the balance spring (1) can be held by tightening, a screw (11) for tightening the stud, for securing the balance spring (1) by interposing it between the stud (10) and a bearing surface (7), the tightening screw (11) having a point (15) provided in the extension of the threaded body (12) opposite the screw head, the stud (10) having a recess (16) into which the point (15) can be inserted. The corresponding watch and the method for securing the outer end of the balance spring are also provided.