Flexible Pivot Oscillator Impulse Pin Positioning
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Solution Overview
Problem
Watch oscillators with flexible pivot mechanisms face isochronism defects due to parasitic pitching modes, leading to precision issues in time measurement, particularly evident around specific amplitude ranges.
Innovation Solution
The impulse pin is strategically positioned to avoid exciting parasitic pitching modes by crossing the plane of symmetry of the elastic blades, eliminating or attenuating resonance phenomena, thereby improving isochronism and operational amplitude ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the impulse pin is positioned at a conventional location on the balance, then the oscillator can be manufactured with standard design, but parasitic pitching modes are excited causing isochronism defects
Solution Approach 1:
The impulse pin is positioned at a specific location where its functional zone crosses the plane of symmetry of the median planes of the blades. This localized positioning change eliminates the harmful lever arm while maintaining the oscillator's overall structure and manufacturing simplicity.
Solution Approach 2:
The plane of symmetry of the median planes of the blades serves as a reference intermediary to define the optimal position of the impulse pin. By aligning the impulse pin's functional zone with this symmetry plane, the design eliminates parasitic pitching modes without requiring complex structural modifications.
2Reliability
If the impulse pin is repositioned to cross the plane of symmetry of the elastic blades, then resonance phenomena are eliminated improving isochronism, but the device complexity increases
Solution Approach 1:
Only the impulse pin position is modified locally, while the rest of the oscillator structure remains unchanged. This minimal local modification achieves the goal of eliminating resonance without increasing overall device complexity.
Solution Approach 2:
The position parameter of the impulse pin is optimized to cross the plane of symmetry of the elastic blades. This parameter change eliminates parasitic pitching modes while maintaining the simplicity of the overall device structure.
3Reliability
If the impulse pin functional zone crosses the plane of symmetry of the median planes of the blades, then parasitic pitch mode excitation is avoided, but manufacturing precision requirements increase
Solution Approach 1:
The solution focuses precision requirements on a single critical element (impulse pin position) rather than distributing complexity throughout the device. The impulse pin is positioned to cross the plane of symmetry, which can be achieved through standard manufacturing processes with appropriate fixturing.
Solution Approach 2:
The impulse pin position is defined by a clear geometric parameter (crossing the plane of symmetry of the median planes of the blades), which provides a natural reference for manufacturing and assembly, reducing the actual precision burden despite the increased theoretical requirement.
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 configuration enhances the isochronism of watch oscillators, allowing for independent selection of operational amplitude ranges and reducing precision errors in time measurement.
Implementation Method 1
The flexible pivot 3 comprises first and second elastic blades 5, 6 which are identical but extend in parallel planes and in different directions to cross without contact
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The clockwork oscillator (100') according to the invention comprises a support (1), a balance wheel (2), and a flexible pivot (3) for guiding the balance wheel (2) in rotation relative to the support (1) about a virtual axis of rotation (A) and for exerting a restoring torque on the balance wheel (2). The flexible pivot (3) comprises elastic blades (5, 6) having different respective median planes (P1, P2) perpendicular to the virtual axis of rotation (A), the set of median planes (P1, P2) being symmetrical with respect to a plane of symmetry (P3). The oscillator (100') further comprises an impulse element (4') fixed to the balance wheel (2) and intended to cooperate with an escapement (8). The functional area of the impulse element (4'), intended to be in contact with the escapement (8), passes through the plane of symmetry (P3).