A spiral spring for a horological resonator mechanism, including a flexible strip (2) coiled on itself into several turns, the strip (2) having a predefined stiffness. The spring (1) include an element for adjusting its stiffness, including a unique elongate flexible element (5) arranged in series with the strip (2), and connecting one end (4) of said strip (2) to a fixed support (11), to add additional stiffness. The flexible element (5) has a stiffness higher than that of the strip (2). A prestressing element (6) applies two different efforts on the element (5), and includes a first lever (8) attached to the end (4) of the strip (2) to allow adjusting a first effort, and a second lever (8) also attached to the end (4) of the strip (2) to adjust a second effort independently of the first effort.

A spiral spring for a horological resonator mechanism, including a flexible strip (2) coiled on itself into several turns The spring (1) including an element for adjusting its stiffness, which includes a first elongate flexible element (5), and a second elongate flexible element (15) arranged in series with the strip (2), each elongate flexible element (5) connecting the same end (4) of the strip (2) to a fixed support (11), so as to add an additional stiffness to the strip (2), each elongate flexible element (5) preferably having a stiffness higher than that of the strip (2). A prestressing element (6) applies at least two different adjustable efforts, the two efforts being applied on the first elongate flexible element (5) so as to make the stiffness of the first elongate flexible element (5) vary according to the prestress level.

Method for press-rolling a mainspring, from a wire comprising a pre-formed eye, utilizing a roller press comprising a first support and guide means exerting a force on the wire in a first contact area located between a second and a third contact area comprised in a second and a third support and guide means, in order to wind, beyond the eye, an accumulation area with an opposite curvature to that of the eye, and wherein, as the wire advances, the position of the first contact area is gradually moved away from the second and third contact areas, to vary the press-rolling radius from a first minimum value to a second maximum value at a neck junction between the accumulation area and the eye.

The spiral includes turns of rectangular section, whose pitch p and/or thickness e can vary from the inside curve towards the outside curve, or whose winding can deviate from the line of a perfect spiral. The inside curve can also be extended by a self-locking washer for fixing the spiral on the balance arbour with no play. The spiral is manufactured by photolithography and galvanic growth, or by micro-machining an amorphous or crystalline material, such as a silicon wafer.

Process for manufacturing a hybrid timepiece component, comprising structuring at least one wafer (14) of a first micromachinable material so as to form at least one through-opening (15) within the wafer (14), said structured wafer (14) being intended to form a first part (4) of the hybrid timepiece component; and depositing a metal by electroforming, so that the metal extends through the through-opening (15) and over the two upper and lower faces of the wafer (14) as a single piece resulting from one and the same electroforming step, the electroformed metal being intended to form a second part (8) of the hybrid timepiece component.

A timepiece includes a mechanical oscillator, formed by a balance and a piezoelectric balance spring, and a regulating device for regulating the frequency of the mechanical oscillator which is arranged to be able to produce time-separated regulating pulses, each consisting of a momentary decrease in an electrical resistance applied by the regulating device between two electrodes of the balance spring relative to a nominal electrical resistance. Each regulating pulse produces a variation of rate which varies as a function of its moment of starting in a half-period of the mechanical oscillator, the characteristic function of this variation of rate relative to the moment of starting of at least one regulating pulse respectively in at least one half-period of the mechanical oscillator being negative in a first temporal zone of at least one half-period and positive in a second temporal zone of at least one half-period.

An assembly (300) includes (i) a hairspring (2) made of a paramagnetic alloy including at least one of the following elements: Nb, V, Ta, Ti, Zr and Hf, notably an alloy including the elements Nb and Zr with between 5% and 25% by mass of Zr and an interstitial doping agent including oxygen, and (ii) at least one fastening part (1; 1), notably two parts (1; 1), in particular a stud (1) or a collet (1), for an end (2a; 2b) of the hairspring (2), the at least one part (1; 1) having a first portion (10; 10) that is designed to come into contact with the hairspring (2) and that is made of titanium or titanium alloy or of tantalum or tantalum alloy, notably grade 2 titanium or grade 5 titanium.

A method for treating a surface (2) of a base (1) of a timepiece component (10), in particular a balance spring, e.g. a balance spring made of a paramagnetic NbZr alloy, includes: a first step of depositing a first layer (41) of a first oxide or first nitride or first carbide; and a second step of depositing a second layer (51) of a second oxide or second nitride or second carbide.

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.

An antiferromagnetic alloy consisting of: between 10.0 and 30.0 wt.-% manganese, between 4.0 and 10.0 wt.-% chromium, between 5.0 and 15.0 wt.-% nickel, between 0.1 and 2.0 wt.-% titanium, the remainder being iron and residual impurities, the alloy being free of beryllium.