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 (A1) 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 ; characterised in that 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 . - An hour snail ; - An hour part bearing an hour feeler-spindle and mounted in rotation about an hour axis (A1) 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 ; • 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 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 ; - 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; • 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 . <EOS>