Contactless cylinder escapement

A timepiece escapement mechanism, arranged to cooperate with means for providing torque and comprising at least one escape wheel, which is subjected to a rotational torque, whose moment is lower than or equal to a nominal moment, about a first pivot axis, under the action of said means for providing torque, and comprising a regulating member integral with a regulating wheel set mounted to pivot about a second pivot axis, wherein said escapement mechanism constitutes a magnetic cylinder escapement, and in that said escape wheel comprises a plurality of actuators, regularly spaced around the periphery of a first disc, pivoting integrally with said escape wheel, said actuators each comprising magnetically charged or ferromagnetic magnetic field conductor parts, and each being arranged to work in attraction, via said first disc, with at least a second disc comprised in said regulating wheel set and pivoting integrally therewith, said second disc being soft ferromagnetic and not magnetically charged, each said actuator including at least:

• a first magnetic impulse part, and a second magnetic stop part, which generate or guide magnetic fields of substantially the same direction and the same sense, substantially parallel to said first pivot axis of said escape wheel, and in that said escape mechanism comprises, substantially in the same plane as said second disc, a conductive ferromagnetic plate, disposed underneath said first disc and not in contact therewith, said plate comprising a cutout which surrounds, in a contactless manner, the periphery of said second disc, so as to provide a variable air-gap between said plate and said second disc, and said plate being arranged to ensure the closing of the magnetic circuit formed by at least one said actuator, said first disc, said second disc, and a structure in which said escape wheel pivots and which carries said plate, and wherein said second disc comprises a first peripheral area defining with said plate a first air-gap greater than a second air-gap that exists between said plate and a second peripheral area adjacent to said first area, and in that said actuators and said first air-gap and said second air-gap are dimensioned such that a said first magnetic part can only cross said second air-gap and is blocked by said first air-gap.