Patent ID: 7553067

Claim:
A return-to-zero hammer for clockwork movement designed to cooperate with at least one first and one second heart-piece of said movement having respective axes of rotation located apart from each other, the hammer comprising at least two parts whereof a first is designed to be mounted on said movement so as to be movable relative to the latter, while a second of said parts comprises at least two support surfaces designed to cooperate with said first and second heart-pieces, respectively, said first and second hammer parts being connected to each other so as to allow a limited movement of one of the parts relative to the other, wherein at least one first organ of said first part is connected to a first organ of the said second part by a ball and socket joint formed, on one hand, by a protuberance having a disc-shaped principal portion arranged on one of said parts and, on the other hand, by a recess arranged in the other of said parts and having a shape substantially complementary to that of said protuberance.