Abstract: A single direction coupling device, including a first transmission member (10) fitted with a first saw-like contrate toothing (13), mobile in rotation about an axis XX and axially positioned by an elastic member (11), and a second transmission member (14) fitted with a second saw-like toothing (17), mobile in rotation about an axis YY, meshed with the first transmission member (10), characterized in that the XX axis is perpendicular to the YY axis.

Abstract: The stop second device during precise time-setting of a watch fitted with a tourbillon (1) comprises mobile elements such as levers (14, 15, 16) mounted in the carriage (2) of the tourbillon, each of said mobile elements being returned by a return spring (28, 29, 30). These mobile elements are capable of contacting the periphery of the balance (3) of the tourbillon, to block said balance when action is exerted on at least one of said mobile elements by a shoe (17) arranged outside the carriage (2) and controlled by the time-setting stem (26) of the watch. The outer edges (18, 19, 20) of the levers are located above pillars (4) of the carriage (2), such that the shoe (17) can act on the levers without interfering with said pillars.