Magnetic Escapement Self-Starting via Segmented Coupling
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Solution Overview
Problem
Magnetic escapements in horological movements often face difficulties in self-starting after being stopped, due to magnetic coupling issues between the escape wheel and pallet assembly, leading to inadequate energy transfer to the mechanical resonator for normal oscillation.
Innovation Solution
The design incorporates a magnetic coupling system with distant portions on the escape wheel and pallet assembly, allowing for a monotonic equilibrium angular position that facilitates magnetic force impulses and mechanical starting forces, ensuring rapid self-starting by aligning the pallet assembly's movement with the escape wheel's rotation, even when the mechanical resonator is at rest.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a magnetic coupling system is used between the escape wheel and pallet assembly, then the escapement can provide sustained oscillations to the mechanical resonator during normal operation, but the escapement cannot self-start after being stopped due to magnetic locking between the pallet assembly and escape wheel
Solution Approach 1:
The magnetic coupling system is segmented into multiple magnetic interactions: attraction zones for normal operation and a repulsion zone for starting. The periodic magnetised structure creates alternating attraction and repulsion regions, allowing the pallet-stone to be propelled during starting while providing controlled coupling during operation.
Solution Approach 2:
The periodic magnetised structure is pre-configured with ascending ramps that create a monotonic increase in magnetic potential energy. This preliminary arrangement of magnetic fields ensures that when the escape wheel rotates, the pallet-stone automatically follows the energy gradient and receives propulsive impulses without requiring external intervention to break magnetic locking.
2Power
If the pallet assembly is mechanically coupled to the mechanical resonator, then the resonator can be driven during oscillation, but the escapement fails to provide sufficient energy to start the resonator's oscillation
Solution Approach 1:
The starting mechanism replaces direct mechanical coupling with a magnetic field-based propulsion system. The periodic magnetised structure creates magnetic potential energy ramps that actively propel the magnetic pallet-stone, generating starting impulses without relying on mechanical friction or direct contact during the critical starting phase.
Solution Approach 2:
The magnetic field parameters are specifically designed to create a monotonic increase in magnetic potential energy along the ramps. This parameter configuration ensures that the magnetic force consistently acts in the direction of motion during starting, providing sufficient energy transfer to initiate resonator oscillation.
3Force
If the escape wheel and pallet assembly are in direct magnetic contact, then magnetic force can be transmitted efficiently, but magnetic repulsion can cause mutual locking at certain angular positions
Solution Approach 1:
The magnetic interaction is made non-uniform through the periodic magnetised structure with varying pole configurations. Different angular positions create different magnetic field qualities: attraction-dominated zones for force transmission and repulsion-dominated zones for preventing locking, allowing both functions to coexist in different spatial locations.
Solution Approach 2:
The magnetised structure is arranged periodically around the escape wheel, creating repeating sequences of magnetic interactions. This periodic arrangement ensures that repulsion forces occur at regular intervals to prevent locking, while attraction forces provide continuous propulsion, maintaining operational stability through rhythmic magnetic cycling.
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 enables effective and rapid self-starting of the escapement, ensuring sustained oscillations of the mechanical resonator by providing mechanical and magnetic starting impulses, overcoming the limitations of existing magnetic escapements.
Implementation Method 1
magnetic coupling system between an escape wheel and a pallet assembly separated from the mechanical resonator
Implementation Method 2
Said magnetic pallet-stone and the periodic magnetised structure are arranged in such a way that the pallet assembly undergoes a magnetic force impulse
Data Source
AI summary
A horological movement includes an escapement with a magnetic system to generate magnetic force impulses, so as to sustain the oscillation of the mechanical resonator associated with the escapement. In order to make possible an effective self-starting of the assembly formed of the mechanical resonator and of the escapement during a winding of the barrel, after a stop of the horological movement due to the unwound barrel spring, the escape wheel includes teeth and the pallet assembly includes two mechanical pallet-stones arranged to receive, upon starting, at least one mechanical force impulse of the escape wheel via one of the teeth thereof, the mechanical force impulse generating a starting force torque on the pallet assembly that is transmitted to the balance of the mechanical resonator to begin an oscillation of the latter so that the assembly can operate normally after a starting phase.