Balance Spring Length Adjustment for Gravity-Stable Watch Oscillation
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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 gravity-induced frequency variations and lack precision, leading to inconsistent watch rate due to orientation changes and mechanical disturbances.
Innovation Solution
An autonomous adjustment device for the balance spring, featuring a lever pivoting on a stud carrier, a freely rotating weight, and damping means, which adjusts the balance spring length autonomously to counterbalance gravity effects and stabilize isochronism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual adjustment mechanisms are used to adjust the active length of the balance spring, then the watchmaker can modify the balance wheel's frequency, but gravity influences the frequency depending on the orientation of the watch movement causing rate variation between horizontal and vertical positions
Solution Approach 1:
The device employs a weight that rotates freely under gravity to autonomously adjust the active length of the balance spring according to the watch's orientation. This self-regulating mechanism eliminates the need for manual intervention while automatically compensating for gravity's influence on frequency stability.
Solution Approach 2:
The freely rotating weight acts as a gravity-sensing element that provides feedback about the watch's orientation. This feedback drives the cam mechanism to modify the balance spring's active length, creating a closed-loop system that automatically maintains frequency stability despite changes in gravitational direction.
2Ease of repair
If a pin-eccentric clamping system is used to secure the balance spring terminal portion, then the clamping can be loosened or tightened by a watchmaker, but the precision of adjustment is significantly limited and the process is tedious
Solution Approach 1:
The invention replaces the discrete pin-eccentric clamping mechanism with a continuous cam-based adjustment system. The cam's profile allows for precise, continuous modification of the balance spring's active length, eliminating the limitations of discrete pin positions while maintaining ease of operation through the freely rotating weight.
3Adaptability or versatility
If the balance spring moves between pins due to play between them, then the spring can adjust, but the oscillations cause disturbance in the active length and variation in frequency
Solution Approach 1:
The invention transitions from a static pin-based system to a dynamic cam-based system. The cam profile is designed to work in conjunction with the balance spring's natural oscillations, providing continuous adjustment that adapts to the spring's movement while maintaining frequency consistency through the gravity-driven feedback mechanism.
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 precisely compensates for gravity-induced perturbations in the balance wheel's isochronism, ensuring consistent oscillation frequency regardless of the watch's orientation, with automatic adjustments and damping to prevent sudden changes.
Implementation Method 1
a movable weight rotating about a shaft on which a cam is mounted, the weight being arranged to rotate freely about the shaft according to gravity
Implementation Method 2
elastic constraint means configured to exert an elastic restoring action in position on the lever
Implementation Method 3
damping means comprising a toothed wheel coaxial with and mounted on the weight, and a damping device arranged to cooperate with the weight via the toothed wheel and limit the change in the active length of the balance spring in the event of sudden acceleration or deceleration
Data Source
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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 first 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).