Timepiece Escapement Self-Starting Profile Geometry
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Solution Overview
Problem
Potentially self-starting escapement mechanisms in timepieces often fail to restart on their own when the barrel is fully wound, due to insufficient barrel torque to overcome the return torque of the oscillator, leading to inconsistent self-starting behavior.
Innovation Solution
Optimizing the geometry of the pallet and tooth profiles in the escapement mechanism to maintain a nearly constant return torque over the entire angle of lift, minimizing the maximum moment of the elastic return means and reducing the torque required for self-starting by introducing a succession of zones that assist and oppose the escapement wheel, thereby enhancing the self-starting capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the barrel is fully wound, then the barrel torque is maximized, but the return torque of the oscillator remains too high for the escapement to start on its own
Solution Approach 1:
The invention changes the geometric parameters of the pallet and tooth profiles to modify the torque characteristics. By optimizing the shape of the pallet (including the impulse plane and rest plane) and the corresponding tooth profile, the system achieves a more favorable torque balance that enables self-starting even with standard barrel torque levels.
Solution Approach 2:
The invention applies different geometric characteristics to different zones of the pallet and tooth interfaces. The impulse plane, rest plane, and various angular portions are designed with specific local geometries that create zones of assistance and opposition, optimizing the torque distribution throughout the escape arc.
2Force
If the pallet and tooth geometry is optimized for constant return torque, then the torque required for self-starting is reduced, but the manufacturing complexity increases
Solution Approach 1:
The pallet and tooth profiles are segmented into distinct functional zones: rest plane, impulse plane, and various angular portions. Each zone can be manufactured separately with specific geometric characteristics, making the complex overall design more manageable through modular fabrication approaches.
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 optimized geometry significantly reduces the torque needed for self-starting, achieving a torque reduction of up to four times compared to standard designs, ensuring reliable and consistent restart of the balance oscillation without manual intervention.
Implementation Method 1
a mechanical oscillator (400) with an inertial mass (40) returned by elastic return means (50)
Implementation Method 2
at least one lever (10) arranged to cooperate, on the one hand, with an inertial mass (40) of a mechanical oscillator (400), and subjected, directly or indirectly, to the action of elastic return means (50) included in said mechanical oscillator (400), and, on the other hand, at pallets (1) carried by or included in said lever (10), with teeth (2) included in said at least one escapement wheel (20)
Data Source
AI summary
A timepiece escapement mechanism, including a lever and an escapement wheel, the lever being arranged to cooperate with an inertial mass of a mechanical oscillator, and, at pallets carried by or included in the lever, with teeth of the escapement wheel, where the contact between a pallet and an escapement tooth includes at least three zones, a rest zone where the torque is of negative direction, where the angle between the normal to the contact and the radial of the lever is negative, a first zone corresponding to the first half angle of lift where the torque is of positive direction, where the angle ω1 is positive, and a second zone corresponding to the second half angle of lift where the torque is of positive direction, where the angle ω2 is positive.