A method for determining an imbalance characteristic of a hairspring (5) balance (4) oscillator (3) of a timepiece movement (2), the method comprising at least the following steps: Setting the hairspring balance oscillator in an oscillating motion at at least two amplitudes, Determining, for each amplitude and for at least two positions of the oscillator, a piece of data representative of the oscillation period of the oscillator, Using the data from the previous step to calculate the imbalance characteristic of the hairspring balance oscillator.

The mechanical timepiece movement includes at least one barrel, a set of gear wheels driven at one end by the barrel, and an escapement mechanism of a local oscillator with a resonator in the form of a sprung balance and a feedback system for the timepiece movement. The escapement mechanism is driven at another end of the set of gear wheels. The feedback system includes at least one precise reference oscillator combined with a frequency comparator to compare the frequency of the two oscillators and a mechanism for regulating the local oscillator resonator to slow down or accelerate the resonator based on the result of a comparison in the frequency comparator.

The mechanical timepiece movement includes at least one barrel, a set of gear wheels driven at one end by the barrel, and an escapement mechanism of a local oscillator with a resonator in the form of a sprung balance and a feedback system for the timepiece movement. The escapement mechanism is driven at another end of the set of gear wheels. The feedback system includes at least one precise reference oscillator combined with a frequency comparator to compare the frequency of the two oscillators and a mechanism for regulating the local oscillator resonator to slow down or accelerate the resonator based on the result of a comparison in the frequency comparator.

The invention relates to a method for fabrication of a balance spring of a predetermined stiffness comprising the steps of fabricating a balance spring in dimensions of increased thickness, determining the stiffness of the balance spring formed in step a) in order to remove a volume of material to obtain the balance spring having the dimensions necessary for said predetermined stiffness.

The invention relates to a method for fabrication of a balance spring of a predetermined stiffness comprising the steps of fabricating a balance spring in dimensions of increased thickness, determining the stiffness of the balance spring formed in step a) in order to remove, locally, a volume of material, in order to obtain the balance spring having the dimensions necessary for said predetermined stiffness.

The invention relates to a method for fabrication of a balance spring of a predetermined stiffness comprising the steps of fabricating a balance spring in dimensions to obtain a deliberately lower stiffness, determining the stiffness of the balance spring formed in step a) in order to compensate for said missing thickness of material required to obtain the balance spring having the dimensions necessary for said predetermined stiffness.

Method for testing a balance spring or a balance spring blank arranged to form a balance spring, the balance spring being required to have at least one predetermined expected resonance frequency, the testing method including the following steps: a. applying to the balance spring or balance spring blank, a vibratory excitation that varies over time in order to cover a predetermined frequency range, b. identifying at least one characteristic of a resonance frequency of the balance spring or balance spring blank, such as a resonance peak, during, or in response to, the vibratory excitation over the predetermined frequency range, c. subjecting the resonance frequency characteristic identified in step b. to a prediction machine in order to determine if the balance spring or balance spring blank is affected by a defect.

Method for testing a balance spring or a balance spring blank arranged to form a balance spring, the balance spring being required to have at least one predetermined expected resonance frequency, the testing method including the following steps: a. applying to the balance spring or balance spring blank, a vibratory excitation that varies over time in order to cover a predetermined frequency range, b. identifying at least one characteristic of a resonance frequency of the balance spring or balance spring blank, such as a resonance peak, during, or in response to, the vibratory excitation over the predetermined frequency range, c. subjecting the resonance frequency characteristic identified in step b. to a prediction machine in order to determine if the balance spring or balance spring blank is affected by a defect.

The mechanical timepiece movement includes at least one barrel, a set of gear wheels driven at one end by the barrel, and an escapement mechanism of a local oscillator with a resonator in the form of a sprung balance and a feedback system for the timepiece movement. The escapement mechanism is driven at another end of the set of gear wheels. The feedback system includes at least one precise reference oscillator combined with a frequency comparator to compare the frequency of the two oscillators and a mechanism for regulating the local oscillator resonator to slow down or accelerate the resonator based on the result of a comparison in the frequency comparator.

A method for manufacturing an oscillator for a timepiece made from a balance and a balance spring, the method including measuring the average moment of inertia of a batch of balances; providing pinned up balance springs, the balance springs having an excess number of coils forming up to three more turns than the final number of coils; making a first predetermined external cut of the balance springs over a length of one to two coils, then measuring the torque of the balance springs and sorting them according to the value of the measured torque; assembling the balance springs, whose measured torque corresponds to the balances, are assembled to form an oscillator with an intermediate frequency and to determine the length to be cut to achieve the desired oscillation frequency; making a second external cut of the balance springs selected to achieve both the desired oscillation frequency and a target value.