A mechanical clock movement includes a resonator, an escapement linked to the resonator, and a display of at least one item of time information. The display is driven by a mechanical drive device via a counter wheel train, the work rate of which is set by the escapement. At least the resonator is housed in a chamber, in which a reduced pressure in relation to atmospheric pressure prevails. The escapement is a magnetic escapement including an escape wheel coupled directly or indirectly to the resonator via a non-contact magnetic coupling system, wherein the magnetic coupling system is formed so that a non-magnetic wall of the chamber runs through the magnetic escapement so that a first part of the escapement is located inside the chamber whereas a second part of the escapement is located outside the chamber.

Method for creating a flexible, multistable element (5): a silicon component (S) is etched with a beam (P) connecting two ends (E1, E2) of a rigid mass (MU) having a cross-section more than ten times that of said beam (P), SiO.sub.2 is grown at 1100° C. for a duration adjusted to obtain, on said beam (P), a first ratio (RA) of more than 1 between the section of a first peripheral layer (CP1) of SiO.sub.2, and that of a first silicon core (A1), and, on said mass (MU), a second ratio (RB) between the section of a second peripheral layer (CP2) of SiO.sub.2 and that of a second silicon core (A2), which is less than a hundredth of said first ratio (RA); cooling to ambient temperature is performed, to deform said beam (P) by buckling when said mass (MU) cools and contracts more than said beam (P).

Method for creating a flexible, multistable element (5): a silicon component (S) is etched with a beam (P) connecting two ends (E1, E2) of a rigid mass (MU) having a cross-section more than ten times that of said beam (P), SiO.sub.2 is grown at 1100° C. for a duration adjusted to obtain, on said beam (P), a first ratio (RA) of more than 1 between the section of a first peripheral layer (CP1) of SiO.sub.2, and that of a first silicon core (A1), and, on said mass (MU), a second ratio (RB) between the section of a second peripheral layer (CP2) of SiO.sub.2 and that of a second silicon core (A2), which is less than a hundredth of said first ratio (RA); cooling to ambient temperature is performed, to deform said beam (P) by buckling when said mass (MU) cools and contracts more than said beam (P).

A method for maintaining and regulating frequency of a timepiece resonator mechanism around its natural frequency, the method including: at least one regulator device acting on the resonator mechanism with a periodic motion, to impose a periodic modulation of resonant frequency or quality factor or a position of a point of rest of the resonator mechanism, with a regulation frequency between 0.9 times and 1.1 times the value of an integer multiple of the natural frequency, the integer being greater than or equal to 2 and less than or equal to 10, and the periodic motion imposes a periodic modulation of the quality factor of the resonator mechanism, by acting on losses and/or damping and/or friction of the resonator mechanism.

A method for maintaining and regulating frequency of a timepiece resonator mechanism around its natural frequency, the method including: at least one regulator device acting on the resonator mechanism with a periodic motion, to impose a periodic modulation of resonant frequency or quality factor or a position of a point of rest of the resonator mechanism, with a regulation frequency between 0.9 times and 1.1 times the value of an integer multiple of the natural frequency, the integer being greater than or equal to 2 and less than or equal to 10, and the periodic motion imposes a periodic modulation of the quality factor of the resonator mechanism, by acting on losses and/or damping and/or friction of the resonator mechanism.

Watch or movement including a timepiece resonator movement including two RCC flexural pivots mounted in series about an intermediate rotary support and having the same virtual pivot axis, each comprising two straight flexible strips of the same length, whose clamping points opposite to this pivot axis are at the same distance with respect to this axis, and which define linear directions, forming angles, in pairs, with this virtual pivot axis, whose value expressed in degrees is comprised between:

109.5+5/[(D/L)−(2/3)] and 114.5+5/[(D/L)−(213)],

or more particularly between 107+5/((D/L)−(2/3)) and 112+5/((D/L)−(2/3)), this timepiece resonator mechanism is in an advantageous variant a one-piece temperature-compensated silicon resonator.

A method for making a flexure bearing for an oscillator with an inertial element oscillating in a plane supported by flexible strips fixed to a stationary support returning it to a rest position includes: forming the bearing with basic strips in superposed levels, each having an aspect ratio of less than 10; breaking down the number of basic levels into a plurality of sub-units, each including one or two strips joining a basic support and a basic inertial element, which are made by etching substrates; assembling the sub-units by joining their basic inertial elements; and fixing the basic supports to the support, directly or via translational tables along one or two in-plane translational degrees of freedom, of lower translational stiffness than that of the sub-unit.

A method for making a flexure bearing for an oscillator with an inertial element oscillating in a plane supported by flexible strips fixed to a stationary support returning it to a rest position includes: forming the bearing with basic strips in superposed levels, each having an aspect ratio of less than 10; breaking down the number of basic levels into a plurality of sub-units, each including one or two strips joining a basic support and a basic inertial element, which are made by etching substrates; assembling the sub-units by joining their basic inertial elements; and fixing the basic supports to the support, directly or via translational tables along one or two in-plane translational degrees of freedom, of lower translational stiffness than that of the sub-unit.

In an oscillator for a timepiece including a balance and a hairspring, the balance lacks equilibrium, such that: the curves for running of the oscillator owing to weight of the hairspring as a function of the oscillation amplitude of the balance in at least four vertical positions of the oscillator spaced by 90° each pass through 0 at an oscillation amplitude of the balance between 200° and 240°; and between oscillation amplitudes of 150° and 280°, curves representing the running of the oscillator owing to lack of equilibrium in the balance as a function of the oscillation amplitude in the vertical positions each has an average slope of opposite sign to the average slope of the corresponding curve among the curves representing the running of the oscillator owing to the weight of the hairspring. A reduction in the running discrepancies between the vertical positions can thus be achieved.

In an oscillator for a timepiece including a balance and a hairspring, the balance lacks equilibrium, such that: the curves for running of the oscillator owing to weight of the hairspring as a function of the oscillation amplitude of the balance in at least four vertical positions of the oscillator spaced by 90° each pass through 0 at an oscillation amplitude of the balance between 200° and 240°; and between oscillation amplitudes of 150° and 280°, curves representing the running of the oscillator owing to lack of equilibrium in the balance as a function of the oscillation amplitude in the vertical positions each has an average slope of opposite sign to the average slope of the corresponding curve among the curves representing the running of the oscillator owing to the weight of the hairspring. A reduction in the running discrepancies between the vertical positions can thus be achieved.