Electroformed Mainspring With Integral Flange for Precision Positioning
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Solution Overview
Problem
Manufacturing and integrating small flanges onto striking springs in timepieces is challenging due to their small dimensions, leading to high scrap rates and misalignment issues.
Innovation Solution
A one-piece construction of the mainspring with a radially extending extra thickness forming a flange, integrated during electroforming, eliminating separate manufacturing and positioning steps, and ensuring precise alignment with the leaf.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate flanges are manufactured and welded onto the mainspring, then the flange can be added to limit spring movement, but the manufacturing complexity increases and scrap rate increases due to difficulties in manufacturing and fixing small flanges
Solution Approach 1:
The flange is merged with the mainspring blade to form a one-piece structure. The flange is created as an integral part of the blade through electroforming, eliminating the need for separate manufacturing and welding operations. This resolves the contradiction by combining two previously separate components into one, thereby reducing manufacturing complexity while maintaining precise positioning.
Solution Approach 2:
The flange is formed during the electroforming process itself, before the mainspring is completed. By creating the flange as part of the initial electroforming operation rather than as a subsequent assembly step, the positioning precision is ensured from the outset and manufacturing complexity is reduced.
2Reliability
If separate flanges are manufactured and welded onto the mainspring, then the flange can be added to limit spring movement, but the scrap rate increases due to difficulties in manufacturing and fixing small flanges
Solution Approach 1:
The flange and blade are merged into a single electroformed component, eliminating welding operations that cause high scrap rates. The integral construction ensures reliable attachment without the need for separate fixing operations, thereby improving both attachment reliability and manufacturing efficiency.
Solution Approach 2:
The electroforming process itself creates the flange as an integral part of the blade, making the manufacturing process self-sufficient. The flange is formed automatically during the electroforming operation without requiring separate manufacturing or attachment steps, improving productivity while ensuring reliable attachment.
3Manufacturing precision
If the flange is made in one piece with the blade, then the positioning precision is improved, but the manufacturing difficulty increases for small dimensions
Solution Approach 1:
The mechanical process of separately manufacturing and assembling small flanges is replaced with an electroforming process. This electrochemical manufacturing method can precisely form small features and intricate geometries that would be difficult to manufacture mechanically, thereby achieving high positioning precision while maintaining ease of manufacture for small components.
Solution Approach 2:
The manufacturing approach changes from mechanical fabrication to electroforming. By changing the manufacturing parameter from mechanical cutting and welding to electrochemical deposition, the process can achieve high precision for small components while remaining easier to control and execute.
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
Significantly reduces scrap rates and ensures precise positioning of the flange relative to the mainspring leaf, simplifying the manufacturing process and improving the reliability of small dimension mainsprings.
Implementation Method 1
a metal blade (3, 13) wound on itself
Implementation Method 2
the manufacturing process by electroforming of a mainspring (1, 11) according to the invention
Data Source
Figure 1~6
Figure 2~7
AI summary
The invention relates to a mainspring (1, 11, 21) comprising a metal strip (3, 13, 23) wound on itself. According to the invention, the mainspring (1, 11, 21) comprises a raised portion (5, 15, 22, 24, 25) forming a flange (7, 17, 27) integral with the strip (3, 13, 23). The invention also concerns the method for producing the mainspring.