Patent ID: 6846104

Claim:
A tourbillon for a timepiece, comprising: a rotary mount comprising a base plate and a cage connected to said base plate by a plurality of circumferentially distributed pillars, said rotary mount being connectable to a second hand drive of the timepiece for rotation about a rotary axis in a circulating direction; a circular balance wheel pivotable about a pivot pin having one end mounted in said base plate and another end mounted in said cage, wherein said pivot pin is coaxial with said rotary axis of said rotary mount and said pillars of said cage are arranged outside a radially circulating periphery of said balance wheel; an escapement including a pallet and an escape wheel operatively connected to said balance wheel and arranged on said base plate such that said balance wheel and said escapement are enclosed by said base plate and said cage; a setting device for setting the hands of the time piece; and a stop device connected to said setting device and having a double-arm spring movable from a normal position, in which said double-arm spring is arranged radially outside a circulating movement path of said pillars, to a blocking position, in which said double-arm spring comprising one of a V-shaped and U-shaped spring having two spring arms with abutment regions proximate respective free ends of said two spring arms, wherein one of said two spring arms is directed counter to the circulating direction of said rotary mount and the other of said two spring arms is directed in the circulating direction of said rotary mount.