Off-Center Balance Hairspring Fixation Without Glue or Pins
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Solution Overview
Problem
Existing balance springs in mechanical watches face challenges in securing their ends without using glue or pins, which can cause deformation and accuracy issues, and assembly processes are complex and costly.
Innovation Solution
A balance spring design with off-center coils that transition to a centered configuration upon fixation, using a hook-shaped stopping means to engage with a stud, eliminating the need for glue or pins and simplifying assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glue or pins are used to secure the balance spring ends to the stud, then the balance spring can be fixed reliably, but deformation and accuracy issues occur
Solution Approach 1:
The balance spring's own elasticity is utilized to create a self-locking mechanism. When the free end of the last coil is engaged with the stud, the elastic restoring force automatically locks the spring in place without requiring external fasteners like glue or pins, thereby avoiding deformation while maintaining secure attachment
Solution Approach 2:
The invention changes the geometric parameters of the balance spring by creating an asymmetric configuration where the distance between consecutive turns varies. This parameter modification enables the elastic locking mechanism to function properly, allowing reliable fixation without deformation
2Reliability
If traditional fixation methods are used, then the balance spring can be secured, but assembly processes become complex and costly
Solution Approach 1:
The balance spring performs its own fixation function through its elastic properties. The asymmetric coil configuration allows the spring to lock itself onto the stud when engaged, eliminating the need for complex assembly operations and reducing manufacturing complexity
Solution Approach 2:
The invention extracts and eliminates unnecessary fixation components (glue, pins, complex assembly mechanisms) from the system. By relying solely on the balance spring's inherent elasticity and asymmetric geometry, the solution simplifies the assembly process while maintaining reliable securing
3Ease of manufacture
If the balance spring coils are arranged concentrically in the free state, then the structure is symmetric and simple, but reliable fixation without glue or pins cannot be achieved
Solution Approach 1:
The invention introduces asymmetry in the coil arrangement by making the distance between consecutive turns non-uniform. This asymmetric configuration is essential for creating the elastic locking mechanism that enables reliable fixation without glue or pins, while the coils remain concentric in the assembled state
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
The solution provides a reliable, reproducible, and cost-effective method for securing the balance spring ends, enhancing accuracy and reducing assembly time while minimizing mechanical stress and deformation.
Implementation Method 1
The balance spring is a spring that, as its name suggests, takes the form of a spiral when at rest. Winded in a horizontal plane, parallel to the plane of the clockwork mechanism, the balance spring serves only one function: to make the balance wheel oscillate around its equilibrium position
Implementation Method 2
the coils are rearranged concentrically when this spiral is mounted in the balance wheel-spiral assembly mounted in the mechanical clock movement; the fixing of the spiral onto the stud induces an elastic stress in the spiral coils by means of which the locking means is irrevocably engaged in the recess of the stud
Data Source
Figure 1
Figure 2A~2B
Figure 3A~4
AI summary
The invention relates to a balance spring (1) of a balance wheel and balance spring assembly of a mechanical watch movement, the balance spring (1) being formed of a succession of turns (S1,...,Sn) extending between a first free end, called the first inner turn (2), and a second free end, called the last outer turn (6), the turns of the balance spring being arranged off-center in the free state of the spring, the last outer turn (6) of the balance spring (1) terminating in a retaining means for its attachment to a stud (14), the balance spring (1) being centered and its turns concentric when this balance spring (1) is mounted in the balance wheel and balance spring assembly, the turns rearranging concentrically when this balance spring is mounted, the attachment of the balance spring to the stud inducing in the turns of the balance spring (1) an elastic stress by means of which the retaining means is fixed in a way that cannot be lost on the piton (14).