Mechanical timepiece

A mechanical timepiece comprising an oscillator, the oscillating motion of which is maintained by a mainspring, in which a periodic energy storage device is disposed between this mainspring and an escapement associated with said oscillator, wherein this periodic energy storage device comprises a first seconds wheel engaging with said mainspring and a second seconds wheel engaging with said escapement, a setting wheel for connecting these two seconds wheels, a yoke on which said setting wheel is pivotably mounted, the pivot axis of this yoke and that of the second seconds wheel being coaxial, a stop wheel kinematically linked with said first seconds wheel, a finger fixedly connected to said yoke and the trajectory of which cuts that of said stop wheel, an energy storage spring for exerting upon said yoke a force tending to separate said finger from said stop wheel, whereas the force exerted upon said setting wheel by said mainspring serves to press said finger against said stop wheel with a force greater than that exerted by said storage spring, so that the latter is wound to the point where a tooth of said stop wheel abuts against said finger, allowing said storage spring to displace the yoke in the opposite direction in order to transmit its energy to said escapement up to the disengagement of said stop wheel, which, when it releases said first seconds wheel, allows the rewinding of said storage spring.