Bistable Blade Escapement Overwinding for Precision
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Solution Overview
Problem
Bistable elastic blades in timepiece escapements often fail to reach the metastable state close to the unstable state during arming, leading to an intermediate metastable state that delays energy release and affects the precision of oscillations.
Innovation Solution
Deforming the bistable elastic member beyond its unstable state of maximum winding during the winding phase ensures immediate energy release upon blocking, eliminating the intermediate metastable state and enhancing reactivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bistable elastic blade is armed to the metastable state close to the unstable state during winding phase, then the reactivity of the blade is improved, but the manufacturing precision required to achieve this state becomes extremely difficult to obtain
Solution Approach 1:
The patent applies preliminary action by deforming the bistable elastic blade beyond the unstable state of maximum winding during the winding phase, so that the blade is pre-positioned in an optimal state before the blocking member engages. This preliminary deformation ensures that upon release, the blade immediately tilts toward its other stable state without needing to overcome a hard point, thereby improving reactivity without requiring extremely precise manufacturing of the arming mechanism
Solution Approach 2:
The patent changes the deformation parameter of the bistable elastic blade by deforming it beyond the traditional unstable state of maximum winding. This parameter change transforms the blade's state from a metastable position that requires precise arming to a position where the deformation exceeds the unstable state, eliminating the need for high manufacturing precision while maintaining high reactivity
2Productivity
If the bistable elastic blade occupies an intermediate metastable state before the unstable state during disengagement, then the energy release is delayed, but the blade structure remains simpler
Solution Approach 1:
The blocking member is designed to engage the winding member at a position corresponding to a deformation of the bistable elastic blade that exceeds the unstable state of maximum winding. This preliminary positioning action ensures that the blade is already past the unstable state before blocking occurs, so that upon release, energy is immediately released without the blade needing to pass through an intermediate metastable state, thereby increasing the speed of energy release
3Measurement precision
If the bistable elastic blade is deformed beyond the unstable state of maximum winding, then the precision of pulse delivery is improved, but the stress on the blade during winding phase increases
Solution Approach 1:
The patent changes the deformation parameter of the bistable elastic blade beyond the unstable state of maximum winding, which improves the precision of pulse delivery timing by ensuring immediate energy release. The stress increase is managed through proper design of the blade's elastic properties and dimensions, allowing it to withstand the increased stress during the winding phase while maintaining its bistable characteristics
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 approach improves the precision of the pulse delivery to the oscillator, promoting isochronism and accuracy by ensuring immediate energy transfer without the need to overcome a hard point during disengagement.
Implementation Method 1
a bistable elastic member (5), a winding member (3) arranged to be driven by the drive in order to arm the bistable elastic member during winding phases
Implementation Method 2
a blocking member for blocking the drive member at the end of each winding phase
Implementation Method 3
an impulse member arranged to be driven by a relaxation of the bistable elastic member triggered by an oscillator after each winding phase in order to communicate an impulse to the oscillator
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a watch escapement (1) comprising a drive member (2), a bistable elastic member (5), a winding member (3) arranged to be driven by the drive member (2) in order to wind the bistable elastic member (5) during winding phases, a blocking member (4a, 4b) for blocking the drive member (2) at the end of each winding phase, and a pulse member (4c) arranged to be driven by a release of the bistable elastic member (5) triggered by an oscillator (10) after each winding phase in order to impart a pulse to the oscillator (10). The escapement (1) is characterized in that it is arranged so that, at the end of each winding phase, the bistable elastic member (5) is deformed beyond an unstable maximum winding state.