Watch Barrel Spring Groove Attachment Reduces Bung Diameter
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Solution Overview
Problem
Existing watch barrel designs face challenges in securely attaching the barrel spring to the shaft without severe plastic deformation, while minimizing the bung diameter and maintaining the standard arrangement of the barrel, which affects the pivoting of the drum and cover.
Innovation Solution
A watch barrel design featuring a barrel shaft with a circumferential groove that accommodates a trapezoidal-shaped spring hooking element, allowing for a reliable and industrial attachment without deformation, and reducing the bung diameter by machining a dovetail-shaped internal end of the spring to fit within the groove, enabling increased winding turns and power reserve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the barrel spring is attached to the shaft using traditional methods (screw, friction, or deformation), then the spring can be secured to the shaft, but the spring undergoes severe plastic deformation or the attachment is unreliable
Solution Approach 1:
The invention divides the attachment system into two separate components: a male element integrated with the spring and a female element integrated with the shaft. This segmentation allows each element to be optimized for its specific function without compromising the spring's integrity, eliminating the need for severe deformation or unreliable friction-based attachment.
Solution Approach 2:
The male element of the attachment system is nested within the groove of the female element. The male element fits precisely into the circumferential groove machined into the shaft, creating a secure mechanical interlock that maintains spring integrity while ensuring reliable attachment.
2Duration of action of moving object
If the bung diameter is reduced to increase winding turns and power reserve, then the power reserve is enhanced, but the standard arrangement of the barrel and pivoting of drum and cover cannot be maintained
Solution Approach 1:
The invention applies local quality by creating a circumferential groove at the specific location where the spring attaches to the shaft. This localized feature allows the spring to be securely attached without requiring a larger bung diameter, enabling reduction of the bung diameter by 25% while maintaining the standard barrel arrangement and drum/cover pivoting functionality.
3Duration of action of moving object
If the bung diameter is reduced, then the number of winding turns increases and power reserve is enhanced, but the attachment of the spring to the shaft becomes more difficult without deformation
Solution Approach 1:
The male element is pre-formed with the appropriate geometry to fit into the circumferential groove of the female element. This preliminary preparation of the attachment elements allows for easy assembly without requiring severe deformation of the spring or complex manufacturing processes, even with the reduced bung diameter.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a barrel spring (2) including: an inner end (5) and an outer end; a first portion (50) having a first height (H); a second portion (52) having a second height (h) that is smaller than the first height (H) and being located near the inner end (5); and, at the second portion, e.g. at the inner end, a first attachment element (51) suitable for being attached to the barrel shaft, wherein the second portion is to be inserted into a circumferentially extending groove provided on the barrel shaft.