BARREL WITH A PROFILE SYSTEM WITH ALTERNATING GEOMETRY FOR A TIME PIECE

摘要

The invention relates to a barrel (11) for an automatic watch comprising a drum (4) with an inner side wall (3) and a barrel spring (1) provided with an outer coil (2) which frictionally engages with the inner side wall (3) of the drum (4), the profile of the inner side wall (3) comprising a plurality of alternately arranged sliding arcs of circle (5) and friction arcs of circle (6), wherein the sliding and friction arcs (5, 6) substantially correspond to a geometric arrangement consisting of a profile construction element (7) acting as a geometric reference for determining the positions and dimensions of sliding arcs (5) and friction arcs (6).