A one-piece balance spring including 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 substantially constant distance between each coil from the inner coil to the penultimate coil.

A compensating balance spring for a thermally compensated sprung balance resonator including a core formed from at least one non-metallic material. The core is entirely coated with a layer which is moisture proof to render the balance spring less sensitive to climatic variations. The compensating balance spring can be applied to timepieces.

A governor includes a balance spring including a base member made of silicon, for example, and a balance wheel. The balance spring includes a coating film of DLC that is applied to a surface of the silicon base member to improve the strength of the balance spring. A spring constant of the balance spring changes in accordance with the temperature change. A moment of inertia of the balance wheel changes in accordance with the temperature change. A change in an oscillation period due to the temperature change is suppressed by the change in the spring constant of the balance spring and by the change in the moment of inertia of the balance wheel.

A balance spring includes a strip wound around itself into several coils, the inner coil being integral with a collet including a band extending substantially in the form of a polygon. The outer contour on each bulging portion of the vertices of the polygon includes two axially extending walls substantially parallel to each other relative to the segment formed between the center of the collet and the end of the bulging portion.

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.

A spiral spring and a method of manufacturing the spiral spring are disclosed. The spiral spring includes at least one winding, which includes a core made of a silicon material. The core comprises two long, parallel, straight sides, and two short, parallel, straight sides. At least the opposite long sides of the core are covered by a SiO.sub.2 layer. In the method, the at least one winding is etched out of the silicon material such that the core of the at least one winding of the spiral spring is formed and includes two long, parallel, straight sides and two short, parallel, straight sides.

A resonator of the inertia/elasticity type includes a balance-spring coupled to an inertia flywheel and a system for adjusting the frequency of the resonator including an index-assembly arranged to cooperate with one coil of the balance-spring in order to selectively choose the active length of the balance-spring. The portion of the coil of the balance-spring cooperating with the index-assembly includes at least one area of larger cross-section than the other balance-spring coils for finer adjustment of the frequency of the resonator.

A method for treating at least one balance spring intended to equip a horological movement, said balance spring being made from an NbTi alloy, the method comprising a step of steaming, called climatic steaming, in a temperature range comprised between 30 and 100 C. in an atmosphere having a relative humidity comprised between 60 and 99%.

A balance spring (1) intended to be fitted to a timepiece balance having fixed inertia, the balance spring (1) being formed of a core (10) having lateral faces (10c) connecting an upper face (10a) to a lower face (10b), the balance spring (1) including on one of the lateral faces (10) in one portion of the outer coil (5), a coating formed of one or more layers, the coating including two layers with a first electrically conductive layer (12) coated with a second outer layer (13) made of a ceramic, or a combined layer (13), made of an electrically conductive ceramic. Also a method of manufacturing this balance spring.

A balance spring (1) intended to equip a balance of a horological movement, wherein the balance spring (1) is made of a niobium and titanium alloy containing: niobium: the remainder to 100 wt %; titanium with a weight percentage that is greater than or equal to 1 wt % and less than 40 wt %; traces of other elements chosen from among O, H, C, Fe, Ta, N, Ni, Si, Cu and Al, each of said elements being in the range 0 to 1,600 ppm of the total weight, and the sum of said trace elements being less than or equal to 0.3 wt %.