Repeater mechanism with tensioned chain

A repeater mechanism for a timepiece with a striking mechanism, which comprises:

• An hour snail;
• An hour part bearing an hour feeler-spindle and mounted in rotation about an hour axis between:
• A resting position in which the hour feeler-spindle is offset angularly from the hour snail;
• A reading position in which the hour feeler-spindle comes in contact with the hour snail;
• An hour spring which returns the hour part towards its reading position;
• A striking mechanism barrel, which comprises:
• A barrel shaft;
• A barrel drum,
• A barrel spring, an internal end of which is integral with the barrel shaft and an external end of which is integral with the barrel drum;
• A pulley;
• A chain which is able to be wound up partially on the pulley, the chain being hooked, by a proximal end, on the pulley and, by a distal end, on the hour part;
• wherein the pulley is mobile in rotation relative to the barrel shaft, and the striking mechanism barrel comprises:
• A ratchet, integral in rotation with the barrel shaft and:
• coupled in rotation with the pulley as long as the hour part exerts a traction force on the chain;
• uncoupled in rotation from the pulley as soon as the traction force exerted on the chain by the hour part in the reading position is cancelled out;
• A pulley spring interposed between the ratchet and the pulley, and which exerts on the latter a resistant torque which keeps the chain under tension when the ratchet is uncoupled in rotation from the pulley.