US Patent 11073797 Repeater mechanism with tensioned chain

A repeater mechanism includes: an hour part, which is mobile between a resting position and a reading position; an hour spring that returns the hour part towards its reading position; a chain that is hooked to the hour part; a barrel that includes a shaft, a drum, a spring, a pulley that is mobile in rotation relative to the shaft and on which the chain is hooked, and also a ratchet that is integral in rotation with the barrel shaft and coupled to the pulley as long as the hour part exerts a traction force on the chain, and uncoupled from the pulley as soon as this traction force is cancelled out; and a pulley spring that is interposed between the ratchet and the pulley.