Balance Spring Active-Length Adjustment for Gravity Rate Compensation
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Solution Overview
Problem
Existing manual adjustment mechanisms for the active length of a balance spring in mechanical oscillators are prone to frequency variations due to gravity, leading to inaccuracies in watch rate, and require tedious manual adjustments.
Innovation Solution
An autonomous adjustment device for the active length of a balance spring, utilizing weights that move in response to gravity to adjust the balance spring length via cams and arms, ensuring precise compensation for gravitational perturbations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual adjustment mechanisms are used to adjust the active length of the balance spring, then the watchmaker can adjust the balance wheel's frequency, but gravity influences the frequency depending on the orientation of the watch movement, causing rate variations between horizontal and vertical positions
Solution Approach 1:
The device enables autonomous self-adjustment of the balance spring active length using gravity-actuated weights and cam mechanisms. The system automatically compensates for gravitational effects on the balance wheel frequency without requiring manual intervention, thereby maintaining rate consistency across different orientations while achieving precise frequency adjustment.
Solution Approach 2:
The invention introduces dynamic adjustment capabilities where the active length of the balance spring can change automatically in response to gravitational forces. The cam mechanisms and movable weights allow the system to adapt the spring length dynamically based on the watch's orientation, resolving the contradiction between precise adjustment and rate consistency.
2Ease of operation
If manual adjustment mechanisms with pins and regulators are used, then the active length of the balance spring can be adjusted, but play between the balance spring and pins causes disturbance in active length and variation in oscillation frequency
Solution Approach 1:
The invention extracts and eliminates the problematic pin-based retention system that causes play and instability. By replacing the pin mechanism with a cam-based system that directly engages with the balance spring, the design removes the source of active length disturbance while maintaining ease of adjustment through the cam's geometric profile.
3Manufacturing precision
If clamping means with pin-eccentric systems are used to secure the balance spring, then the terminal portion can be pinched to define active length, but the adjustment process is tedious and requires multiple manual steps
Solution Approach 1:
The autonomous adjustment device eliminates the need for tedious manual clamping and securing steps. The cam mechanisms automatically engage and secure the balance spring at the defined active length without requiring the watchmaker to perform multiple manual operations, thereby maintaining manufacturing precision while significantly reducing procedural complexity.
4Measurement precision
If the regulator rotates to change the counting point position, then the active length of the balance spring is modified, but this manual rotation process is time-consuming and imprecise for counteracting gravitational effects
Solution Approach 1:
The device automatically performs the counting point position adjustment without requiring manual regulator rotation. The gravity-actuated cam mechanisms precisely position the balance spring's active length to counteract gravitational effects, eliminating the time-consuming and imprecise manual rotation process while achieving superior positioning accuracy.
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 device autonomously adjusts the balance spring length to counterbalance gravitational effects, maintaining isochronism precision and reducing manual intervention.
Implementation Method 1
two weights (40, 41) movable in translation in orthogonal planes, the weights being arranged to move in translation according to gravity
Implementation Method 2
elastic constraint means configured to exert an elastic restoring action in position on each arm
Implementation Method 3
elastic return means configured to exert an elastic action of restoring position on the weights
Data Source
Figure 1
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AI summary
The present invention relates to a device (6) for autonomous adjustment of the active length of a balance spring (5), for a balance-spring type oscillator (4, 5), comprising a cock (12) mounted on a plate (13) of a watch movement (2) and in which a balance shaft pivots, the balance spring (5) having an inner end fixed to the balance shaft and an outer end fixed to a stud (8) attached to a stud holder (10), the stud holder (10) being pivotally mounted on the cock (12) concentrically with the balance shaft, and means for modifying the active length of the balance spring (5).