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 method for manufacturing a horological mobile (10) including: depositing a first thin layer (11) with a first material including at least nickel, the periphery of which defines the contour of the geometry of the horological mobile (10); depositing an intermediate layer (12), with a second material including at least nickel and phosphorus, so as to cover a face of the first thin layer (11), the periphery of which corresponds to that of the geometric shape of the first thin layer (11); depositing a second thin layer (13) with the first material, so as to cover a face of the intermediate layer (12), the periphery of which corresponds to that of the geometric shape of the first thin layer (11), wherein the first and the second thin layer (11, 13) are poorer in phosphorus than the intermediate layer (12), or do not contain any phosphorus.

A spiral timepiece spring with a two-phase structure, made of a niobium and titanium alloy, and method for manufacturing this spring, including: producing a binary alloy containing niobium and titanium, with: niobium: the remainder to 100%; titanium: strictly greater than 60% and less than or equal to 85% by mass of the total, traces of components from among O, H, C, Fe, Ta, N, Ni, Si, Cu, Al; applying deformations alternated with heat treatments until a two-phase microstructure is obtained comprising a solid solution of niobium with β-phase titanium and a solid solution of niobium with α-phase titanium, the α-phase titanium content being greater than 10% by volume, wire drawing to obtain wire able to be calendered; calendering or insertion into a ring to form a mainspring, in a double clef shape before it is wound for the first time, or winding to form a balance spring.

A process for producing a metal alloy balance wheel by molding includes a) making a mold in the negative shape of the balance wheel; b) obtaining 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; and e) releasing the balance wheel obtained in step d) from its mold. The process also includes a step for over-molding flexible centering components in the hub.

The method for manufacturing a timepiece component is capable of thermocompensating a functional assembly including the timepiece component. The method includes at least the following actions: a) providing (e1) a substrate (1) of semiconductor or metallic material; b) proceeding with the deposition (e2) of a polycrystalline or monocrystalline silicon layer (5) on the substrate (1); c) releasing (e4) the timepiece component (10) from the substrate (1).

The piezoelectric balance spring (3) is provided for a circuit (10) for self-regulating an oscillation frequency of an oscillating mechanical system (2, 3), or an energy recovery circuit or a motor circuit for actuating the movement or for the automatic maintenance thereof. The piezoelectric balance spring (3) comprises at least one piezoelectric layer (7, 7′, 17, 17′, 27, 27′) disposed on a top face (20) or bottom face of a certain number of coils of the spring in a plane, and at least two pairs of electrodes (8a, 8b, 8c, 8d), whereby the electrodes of each pair are disposed on two opposing faces of the same piezoelectric layer or respectively two piezoelectric layers so as to apply a reverse bias voltage on each pair of electrodes.

A balance wheel including a rim connected to a hub with at least one arm, wherein the balance wheel includes an adjustable auxiliary temperature compensation system mounted in the space defined by the rim to allow adjustable temperature compensation of the balance wheel.

A bimetallic device, the difference in expansion coefficient of which is between 10 and 30 10.sup.−6 K.sup.−1, for providing a resonator with thermal compensation via the balance wheel.

A method for producing a thermocompensated and coloured coil spring including the steps of forming a first layer of silicon oxide on at least one face of the core and on at least one other face of the core, the first layer having a thickness equal to a fraction of the thickness required for achieving thermal compensation, removing the first layer from at least one face of the core, forming a second layer of silicon oxide on at least one face of the core and on at least one other face of the core, the second layer having a thickness equal to the remaining fraction of the thickness required for achieving thermal compensation which is lower than or equal to 1 μm for giving at least one face of the core a colour as a result of the interference effect.

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.