Hairspring Stiffness Adjustment via Prestressed Flexible Elements
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Solution Overview
Problem
Current watch resonator mechanisms face limitations in precision adjustment of the balance spring stiffness, which affects the accuracy of mechanical watches, as traditional adjustment methods are not sufficiently precise and can disrupt the balance.
Innovation Solution
A spiral spring with adjustable stiffness is implemented, featuring a flexible ribbon and additional elongated flexible elements connected to a fixed support, allowing for prestressing with variable forces to modify the stiffness of the elongated elements without altering the ribbon's stiffness, thereby fine-tuning the resonator's operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional regulator methods are used to modify the effective length of the balance spring, then the watch's accuracy can be adjusted, but the adjustment effectiveness remains limited and cannot achieve precision of a few seconds per day
Solution Approach 1:
The patent applies parameter changes by modifying the stiffness of the balance spring through controlled deformation of the ribbon structure. By changing physical parameters (deformation, curvature) of the spring ribbon, the effective stiffness is adjusted, enabling precise control of the resonator's period and achieving high timekeeping accuracy of a few seconds per day.
Solution Approach 2:
The patent implements dynamics by making the balance spring stiffness adjustable rather than fixed. The regulator mechanism allows dynamic modification of the spring's effective stiffness during operation, enabling continuous fine-tuning of the timekeeping rate to achieve precise accuracy.
2Measurement precision
If adjustment screws are arranged in the balance wheel's rim to modify inertia, then finer rate adjustment is possible, but the method disturbs the balance of the balance wheel and does not allow sufficiently fine adjustment
Solution Approach 1:
The patent extracts the adjustment function from the balance wheel structure itself and relocates it to the balance spring ribbon. By removing the adjustment screws from the balance wheel rim and implementing the regulator mechanism within the spring structure, the balance wheel's mass distribution and balance are preserved, eliminating disturbances to its rotational equilibrium.
Solution Approach 2:
The patent introduces an intermediary regulator mechanism that acts between the balance spring and the fixed support. This intermediary device allows indirect adjustment of the spring's effective stiffness without directly modifying the balance wheel, thereby maintaining the wheel's balance while achieving precise rate control.
3Measurement precision
If additional elongated flexible elements are added to the spiral spring structure, then the stiffness can be precisely adjusted, but the device complexity increases
Solution Approach 1:
The patent applies universality by designing the regulator mechanism to serve multiple functions simultaneously: it adjusts the effective stiffness of the balance spring, provides a means for precise timekeeping calibration, and maintains the structural integrity of the spring assembly. The same structural elements perform both support and adjustment functions, reducing overall complexity.
Solution Approach 2:
The patent implements nesting by placing the regulator mechanism within the existing balance spring structure. The adjustment components are nested inside or integrated with the spring ribbon and support structure, allowing the regulation function to be incorporated without significantly increasing external dimensions or overall structural complexity.
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
This solution enables precise adjustment of the resonator's frequency, improving the accuracy of timekeeping by allowing for fine-tuning of the resonator's stiffness without affecting the ribbon's stiffness, resulting in enhanced precision.
Implementation Method 1
a first and a second elongated flexible element, each arranged in series with the ribbon, each elongated flexible element connecting one end of said ribbon to a fixed support, so as to add additional stiffness to the ribbon
Implementation Method 2
the adjustment means comprising prestressing means for applying at least two different adjustable forces, the two forces being applied to the first elongated flexible element so as to vary the stiffness of the first elongated flexible element according to the level of prestress
Data Source
Figure 1~2
AI summary
The invention relates to a spiral spring, particularly for a resonator mechanism in watchmaking, the spiral spring (1) comprising a flexible ribbon (2) wound upon itself in several turns, the ribbon (2) having a predefined stiffness, the spiral spring (1) comprising means for adjusting its stiffness, characterized in that the adjustment means comprise a first elongated flexible element (5), and a second elongated flexible element (15) arranged in series with the ribbon (2), each elongated flexible element (5) connecting one end (4) of said ribbon (2) to a fixed support (11), so as to add additional stiffness to the ribbon (2), each elongated flexible element (5) preferably having a stiffness greater than that of the ribbon (2), the adjustment means comprising preload means (6) for applying at least two different adjustable forces,The two forces are applied to the first elongated flexible element (5) so as to vary the stiffness of the first elongated flexible element (5) according to the level of preload. The invention also relates to a clockwork resonator mechanism comprising such a balance spring (1).