Stud Holder Clamping Structure for Precise Balance Bridge Positioning
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Solution Overview
Problem
Existing stud holders for balance bridges in watch movements suffer from inaccuracies in stud positioning due to displacement during friction mounting, affecting the balance spring's attachment point and angular positioning, which is not adequately addressed by prior art solutions.
Innovation Solution
A stud holder design with a clamping portion featuring distinct rigid and elastic sections, ensuring precise radial and angular positioning by utilizing a first rigid part with high stiffness and a second elastic part with lower stiffness, maintaining the stud's alignment relative to the balance wheel's axis and plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a friction mounting system is used with a split ring clamping element, then the stud holder can be easily mounted on the balance bridge, but the stud positioning accuracy deteriorates due to displacement during assembly
Solution Approach 1:
The clamping element is divided into two distinct parts: a rigid portion and an elastic portion. The rigid portion maintains precise stud positioning while the elastic portion enables friction mounting. This segmentation allows each part to fulfill its specific function without compromising the other, resolving the contradiction between mounting ease and positioning accuracy.
Solution Approach 2:
Different regions of the clamping element are given different mechanical properties. The rigid portion has high stiffness to prevent displacement and ensure accurate stud positioning, while the elastic portion has lower stiffness to allow friction mounting. This local differentiation of properties enables simultaneous achievement of both mounting ease and positioning precision.
2Reliability
If the inner circle of the split ring has a smaller diameter than the mounting surface, then friction mounting is achieved, but the stud displacement increases during assembly
Solution Approach 1:
The clamping element is segmented into rigid and elastic portions. The rigid portion maintains precise stud positioning during mounting, while the elastic portion accommodates the diameter difference between the inner circle and mounting surface, allowing friction mounting without causing stud displacement.
Solution Approach 2:
The stiffness parameter is varied along the clamping element. The rigid portion has high stiffness to prevent displacement, while the elastic portion has reduced stiffness to allow the necessary deformation for friction mounting. This parameter change enables both reliable mounting and precise positioning.
3Ease of operation
If a bayonet mounting system is used with friction clamping, then angular positioning is achieved, but the fixing area undergoes displacement during rotation
Solution Approach 1:
The clamping element is divided into rigid and elastic portions. The rigid portion ensures the fixing area remains stable and does not undergo displacement during bayonet rotation, while the elastic portion allows the necessary movement for angular positioning and friction engagement.
Solution Approach 2:
Different portions of the clamping element have different mechanical properties tailored to their functions. The rigid portion maintains fixing area stability, while the elastic portion enables angular positioning through controlled deformation during bayonet rotation.
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
Enables very precise and predetermined radial and angular positioning of the stud, enhancing the accuracy and stability of the balance wheel and hairspring assembly.
Implementation Method 1
a second part of the clamping section that is elastic and has a second separation zone between the first and third contact areas
Implementation Method 2
The first part of the clamping section is rigid and has a first separation zone between the first and second contact areas
Implementation Method 3
three contact areas designed, once the stud holder is mounted on the balance bridge, to press against the side wall of the projecting part
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
The stud holder (42) includes a clamping portion defining three contact zones (18, 20, 22) designed to press against a lateral wall of a projecting part of the balance bridge. A first contact zone (18) is connected to a second contact zone (20) by a first portion (24A) and to the third contact zone by a second portion (26A) of the clamping portion. The first portion has a first stiffness at a second midpoint (30) of the second contact zone, relative to a first midpoint (28) of the first contact zone, which is greater than three times a second stiffness that the second portion has at a third midpoint (32) of the third contact zone relative to the first midpoint of the first contact zone. The first stiffness is advantageously seven times, and preferably twelve times, greater than the second stiffness.This results in a very precise radial positioning of the stud relative to the axis of rotation of the balance wheel.