The invention relates to an assembly system including a member made of at least a first material including a staff and a shoulder, the staff of the member being received in an aperture of a part made of a second material having little or no plastic domain. According to the invention, the assembly system includes a locking element made of a third material arranged to elastically attach the part between the shoulder of said member and the locking element and in that the locking element is a washer whose internal wall radially grips the staff of said member and whose peripheral portion exerts an elastic radial force vertical to the shoulder of said member in order to secure the assembly of the member-part-locking element.

A metallic glass formed of an alloy including: (a-c-x) atomic % of Ni, with a between 54 and 72; (b-y) atomic % of Nb, with b between 35 and 44; c atomic % of Cu, with c from 0.05 to 9; x atomic % of at least one element chosen from: Co, Fe, Ag, Mn, Pd, Au, Ir, Os, Pt, Re, Rh, Ru and Te, with x from 0 to 20; y atomic % of at least one element chosen from: Hf, Ta, Ti, Cr, Mo, Sc, V, W and Y, with y from 0 to 20; z atomic % of at least one element chosen from: B, Si, Al, Sn, Ca, Ga, In, Mg and Zn, with z from 0 to 10; at most 3 atomic % of Zr; and other elements at most 0.1% by weight each and at most 0.5% by weight in total.

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.

A method of increasing concentricity in use of a spiral hairspring mechanical timepiece; the hairspring having an inner terminal end portion for engagement with a collet, an outer terminal end portion for engagement with a stud, a first limb portion extending from the inner terminal end portion towards the outer terminal end portion, and a stiffening portion positioned at the outer turn of the hairspring and having a cross-sectional second moment of area different to that of the first limb portion such that bending stiffness of the stiffening portion has a greater bending stiffness than the single limb portion. The method includes modifying cross-sectional second moments of an area of the first limb portion and the stiffening portion by minimizing a cost function throughout the amplitude of the rotation of hairspring in use, the cost function being correlated to the net concentricity of the hairspring.

A balance spring includes a strip of polygonal section wound on itself into several coils. At least one coil of the balance spring includes a coil spacer device including at least four stop members mounted on the same face and protruding from the thickness of the at least one coil of the strip. Each of the at least four stop members is arranged to enter into contact with the opposite face of another coil of the strip preventing the other coil from touching the at least one coil in the event of a shock.

A watch including a movement including itself an isochronous timepiece oscillator mechanism including a fixed support bearing a crosspiece carrying N primary resonators each including a weight carried by a rotating flexible bearing fixed to this crosspiece. Each primary resonator has a center of mass which, at rest, is on the virtual pivot axis of its rotating flexible bearing and is arranged to oscillate in rotation about this virtual pivot axis. The primary resonators are arranged in rotational symmetry of order N about a main axis parallel to the virtual pivot axes, and oscillating motions of any two primary resonators are phase shifted by the value of the central angle formed by their respective virtual pivot axes with the main axis.

The invention relates to a one-piece balance spring comprising a single strip wound on itself between an inner coil and an outer coil, the strip having a geometry such that when the angle of contraction of the balance spring has a value of 360 degrees, there is a constant distance between each coil from the inner coil to the penultimate coil.

The invention relates to a one-piece balance spring comprising a single strip wound on itself between an inner coil and an outer coil, the strip having a geometry such that when the angle of contraction of the balance spring has a value of 360 degrees, there is a constant distance between each coil from the second coil to the penultimate coil.

A balance spring for an oscillator of a timepiece, wherein it comprises a component part, in particular at least a coil or a portion of a coil, provided with heavily doped silicon having an ion density greater than or equal to 10.sup.18 at/cm.sup.3, in order to permit the thermo-compensation of the oscillator.

A timepiece balance spring made of micromachinable material including a plurality of stages, each forming a spiral wound spring, parallel to each other and all attached to a common axial collet or to the same balance staff, each stage including, at its respective outer end, its own attachment to a balance spring stud which are independent of those of the other stages, the attachment including a position adjustment with respect to a balance spring stud which are also independent of those of the other stages, the attachment and the position adjustment together forming built-in isochronism correction mechanism for the balance spring, and the position adjustment including a plurality of discrete position adjustment positions including housings each arranged to retain a stud.