Flexible Pivot Oscillator With Offset Crossing Points
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Solution Overview
Problem
Existing flexible pivot timepiece oscillators with separate crossed blades suffer from poor impact resistance, as they tend to pivot around an axis parallel to their plane during vertical impacts, and their frequency is not independent of the watch's orientation or amplitude of oscillation.
Innovation Solution
A timepiece oscillator design featuring a flexible pivot with a first pair of elastic blades intersecting at one point and a second pair intersecting at a different point, both pairs being symmetrical to the center of rotation, which enhances impact resistance and maintains frequency independence from orientation and amplitude, allowing for isochronism or anisochronism compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate crossed blades are used to create a flexible pivot oscillator, then frequency independence from orientation is achieved, but shock resistance deteriorates
Solution Approach 1:
The patent applies asymmetry by intentionally offsetting the crossing point of the blades from the center of rotation. This asymmetric configuration creates a specific stiffness distribution that improves shock resistance while maintaining frequency stability through careful balancing of the blade geometry and material properties.
2Reliability
If blades cross at 7/8 of their length to minimize virtual axis displacement, then frequency independence from orientation is improved, but shock resistance worsens
Solution Approach 1:
The patent applies local quality by varying the blade geometry and material properties at different locations along the blade length. The blades have non-uniform cross-sections and stiffness distributions that are optimized for both frequency stability and shock resistance, with different sections having different mechanical properties to address local requirements.
3Manufacturing precision
If symmetrical blade pairs are used, then manufacturing precision is improved, but frequency independence from amplitude is compromised
Solution Approach 1:
The patent applies parameter changes by carefully adjusting blade geometry parameters such as thickness, width, and material composition to achieve the desired balance between manufacturing feasibility and isochronism. The blade dimensions are optimized to provide both symmetry for manufacturing and specific mechanical properties for frequency stability.
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 design significantly improves impact resistance and maintains frequency stability regardless of the watch's orientation, while allowing for isochronism or adjusting anisochronism to compensate for other defects, ensuring consistent oscillation performance.
Implementation Method 1
a flexible pivot connecting the band to the support to guide the band in rotation relative to the support around a virtual axis of rotation. The flexible pivot is arranged to elastically return the band to a rest position. The flexible pivot comprises a first pair of blades consisting of first and second elastic blades
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The clockwork oscillator (1) comprises a rim (3), a support (2), and a flexible pivot (4) connecting the rim (3) to the support (2) to guide the rim (3) in rotation relative to the support (2) around a virtual axis of rotation (A). The flexible pivot (4) is arranged to elastically return the rim (3) to a rest position. The flexible pivot (4) comprises a first pair of blades consisting of first and second elastic blades (4a, 4b) extending in parallel first and second planes and crossing without contact, and a second pair of blades consisting of third and fourth elastic blades (4c, 4d) extending in third and fourth planes parallel to the first and second planes and crossing without contact.In plan view from above and when the serge (3) is in its rest position, the first pair of blades (4a, 4b) and the second pair of blades (4c, 4d) are symmetrical with respect to the center of rotation (O) of the serge (3) and the crossing point (P1) of the first and second elastic blades (4a, 4b) is offset with respect to the crossing point (P2) of the third and fourth elastic blades (4c, 4d).