Rolex Sa

Marc Cerutti

Richard Bossart

Olivier Hunziker

Frédéric Burger

Denis Favez

A method for determining an imbalance characteristic of a hairspring () balance () oscillator () of a timepiece movement (), the method comprising at least the following steps: &#x2014;Setting the hairspring balance oscillator in an oscillating motion at at least two amplitudes, &#x2014;Determining, for each amplitude and for at least two positions of the oscillator, a piece of data representative of the oscillation period of the oscillator, &#x2014;Using the data from the previous step to calculate the imbalance characteristic of the hairspring balance oscillator.

Method for determining an imbalance characteristic of an oscillator

A device for measuring the torque of a hairspring for a balance wheel-hairspring oscillator includes an arbor on which a seat is arranged, a benchmark element, pivoting means for pivoting the arbor, means for keeping the outer end of the hairspring fixed relative to the arbor during measurement, elastic elements provided on a portion of the seat, and means for acting on the elastic elements. The inner end of said hairspring is secured to a collet, the diameter of the seat of the arbor is of a dimension to allow a driving connection by friction with the wall of an axial aperture of the collet, and the elastic elements are formed to bring, under the action of the action means, the section of the portion of the seat forming the driving connection from a greater dimension to a smaller dimension than that of the axial aperture of the collet.

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Saint-Julien-en-Genevois, France

Marc Cerutti