Patent ID: 7016265

Claim:
A timepiece having a mechanical clockwork-movement driven by a spring and being provided with a mechanical regulator being associated by electromagnetic coupling with an electronic regulator, wherein said mechanical regulator includes a balance spring associated with a balance mounted between a plate and a balance-cock for rotation about an axis, the balance having a rim provided with at least one pair of permanent magnets whose directions of magnetisation are substantially parallel to said axis of the balance, but in opposite directions to each other, wherein said electronic regulator includes at least one fixed coil arranged for cooperating with said magnets via electromagnetic coupling, a rectifier supplied by said coil and provided with at least one capacitor, and an enslaving circuit provided with an oscillator having a frequency and arranged for enslaving the frequency of the mechanical regulator to the oscillator frequency by means of said electromagnetic coupling, and wherein said coil is located on the side of the balance-cock with respect to the rim of the balance, the pair of magnets being covered by a shunt plate made of magnetic material on the side of the plate.