A spiral spring intended to equip a balance of a horological movement, wherein the spiral spring is made of an alloy consisting of Nb, Ti and at least one element selected from Zr and Hf, optionally at least one element selected from W and Mo, possible traces of other elements selected from O, H, Ta, C, Fe, N, Ni, Si, Cu, Al, with the following weight percentages: a content of Nb comprised between 40 and 84%, a total content of Ti, Zr and Hf comprised between 16 and 55%, a content for W and Mo respectively comprised between 0 and 2.5%, a content for each of said elements selected from O, H, Ta, C, Fe, N, Ni, Si, Cu, Al comprised between 0 and 1600 ppm with the sum of said traces less than or equal to 0.3% by weight. The method for manufacturing the spiral spring is also disclosed.

The present invention relates to a wristwatch comprising a mechanical clock movement with a tuning fork resonator. The oscillator preferably comprises a material A with a low internal friction. In the oscillator of the invention, the unwanted symmetrical oscillations are avoided, for example, by the choice of the materials from which the tuning fork is manufactured. According to preferred embodiments, the rod and/or fastening of the oscillator comprises a material having greater internal friction than that of said material A, such that the quality factor Q.sub.2 of the symmetrical oscillations is reduced, in contrast to the quality factor Q.sub.1 of the anti symmetrical oscillation mode.

A process for manufacturing a timepiece oscillator made up of a balance and of at least two spring portions that are arranged in parallel, which includes (a) choosing the frequency f of the oscillator, (b) choosing a balance and spring portions so that the inertia of the balance and the angular stiffnesses of the spring portions allow an oscillator of chosen frequency f to be formed and so that the variations in angular stiffness of the spring portions as a function of temperature are able to thermo-compensate the oscillator, and (c) assembling the chosen spring portions with the chosen balance.

A method for manufacturing a micromechanical component made of a first material, the first material being a material that can become at least partially amorphous, the method including: a) providing a mold made of a second material, the mold including a cavity forming the negative of the micromechanical component; b) providing the first material and forming the first material in the cavity of the mold, the first material having undergone, at a latest at a time of the forming, treatment allowing the first material to become at least partially amorphous; c) separating the micromechanical component thus formed from the mold.

A method for manufacturing a balance spring for a balance, which includes creating a blank from an alloy containing: niobium: the remainder to 100 wt %, titanium: between 40 and 60 wt %, traces of elements selected from the group formed of O, H, C, Fe, Ta, N, Ni, Si, Cu, Al, between 0 and 1600 ppm by weight individually, and less than 0.3 wt % combined; -quenching the blank, such that the titanium of the alloy is essentially in solid solution form with -phase niobium, the -phase titanium content being less than or equal to 5% by volume, at least one deformation step of the alloy alternated with at least one heat treatment step such that the niobium and titanium alloy obtained has an elastic limit higher than or equal to 600 MPa and a modulus of elasticity lower than or equal to 100 GPa, a winding step to form the balance spring being performed prior to the final heat treatment step, prior to the deformation step, a step of depositing, on the alloy blank, a surface layer of a ductile material such as copper, to facilitate the wire shaping process, the thickness of the deposited ductile material layer is chosen such that the ratio of the area of ductile material to the area of NbTi alloy for a given cross-section of wire is less than 1.

A balance spring for a balance with a blank containing: niobium: the remainder to 100 wt %, titanium: between 40 and 60 wt %, traces of elements selected from the group formed of O, H, C, Fe, Ta, N, Ni, Si, Cu, Al, between 0 and 1600 ppm by weight individually, and less than 0.3 wt % combined, a step of -quenching the blank with a given diameter, such that the titanium of the alloy is essentially in solid solution form with -phase niobium, the -phase titanium content being less than or equal to 5% by volume, at least one deformation step of the alloy alternated with at least one heat treatment step such that the niobium and titanium alloy obtained has an elastic limit higher than or equal to 600 MPa and a modulus of elasticity lower than or equal to 100 GPa, a winding step to form the balance spring being performed prior to the final heat treatment step, prior to the deformation step, a step of depositing, on the alloy blank, a surface layer of a ductile material such as copper, the surface layer of ductile material being retained on the balance spring, the thermoelastic coefficient of the niobium and titanium alloy being adapted accordingly.

A process for producing a metal alloy balance wheel by molding, the process including the following steps: a) making a mold in the negative shape of the balance wheel, b) getting hold of a metal alloy that has a thermal expansion coefficient of less than 25 ppm/ C. and is able to be in an at least partly amorphous state when it is heated to a temperature between its glass transition temperature and its crystallization temperature, c) putting the metal alloy into the mold, the metal alloy being heated to a temperature between its glass transition temperature and its crystallization temperature so as to be hot-molded and to form a balance wheel, d) cooling the metal alloy to obtain a balance wheel made of the metal alloy, e) releasing the balance wheel obtained in step d) from its mold.

A mechanical oscillating system for a clock including a balance spring manufactured from a non-metallic, polycrystalline material with a grain size between 10 and 50,000 nm, with a winding area of the balance spring 0.001 mm.sup.2 to 0.3 mm.sup.2, an oscillating body and a shaft for mounting of the oscillating body and the balance spring on the shaft. A spiral spring for a clock being manufactured from a non-metallic material, wherein the non-metallic material is a polycrystalline material with a grain size between 10 and 50,000 nm, and having a linear thermal expansion coefficient smaller than 810.sup.6/K.

A temperature-compensated resonator including a body used in deformation, and a core of the body is formed by a material that is one of glass, ceramic glass, technical ceramic, and metallic glass. At least one part of the body includes a coating whose Young's modulus variation with temperature is of an opposite sign to that of the material used for the core, so that at least a first order frequency variation with temperature of the resonator is substantially zero.

A piezoelectric element for an automatic frequency control circuit. The element includes a balance spring formed of a piezoelectric crystal strip, a first electrode connected to the automatic control circuit, and disposed on at least a first side of the strip, and a second electrode connected to the automatic control circuit and disposed on at least a second side of the strip. The first and second electrodes are placed on one portion or over the entire length of the balance spring in a predetermined angular distribution.