Device for automatic winding of a barrel spring of a horological movement

A device for automatic winding of a barrel spring of a watch comprising:

• an oscillating mass, an entry disk kinematically linked to the oscillating mass, two reduction disks and a ratchet driving disk, each reduction disk including a reduction wheel bearing at least four planetary wheels, and a transmission pinion about which the reduction wheel is loosely mounted, the entry disk being kinematically linked to the two reduction wheels such that, regardless of a direction of rotation in which it is driven by the oscillating mass, it rotates the two reduction wheels in mutually different directions, the planetary wheels comprising teeth of asymmetric shape, so as to form ratchets configured to connect in rotation, in each of said reduction disks, the transmission pinion and the reduction wheel only when said reduction wheel pivots in a predefined direction of rotation, said predefined direction of rotation being identical for either of the reduction wheels, wherein one of the reduction wheels is in mesh with the entry disk and with the other reduction wheel.