A
clockwork mechanism comprising a
kinematic chain including a first moving part (2, 2') fixed for rotation about a first axis of rotation (20, 20') and a second moving part (3, 3') fixed for rotation about a second axis of rotation (30, 30'), the first moving part (2, 2') being meshed with the second moving part (3, 3') at a point of contact (4), the first moving part (2, 2') being configured to be driven directly or indirectly by a driving element and to directly drive the second moving part (3, 3'), a
cam (1) for measuring and / or storing
time information, the
cam (1) comprising a variable
diameter profile with at least one step (11) and at least one jump (12), the
cam (1) being driven directly or indirectly by the second moving part (3, 3'), and a probe for reading the
time information by pressing against the profile of the cam (1), characterized in that the first mobile (2, 2') and the second mobile (3,3') are non-circular
moving parts with conjugate profiles, and in that the
kinematic chain is configured such that the ratio (R1 / R2) between a first distance (R1) measured between the first axis of rotation (20, 20') and the point of contact (4) and a second distance (R2) measured between the second axis of rotation (30, 30') and the point of contact (4) is greater when at least one step (12) is opposite the feeler than when a part of at least one rung (11) is opposite the feeler. A timepiece comprising a watch movement and such a timekeeping mechanism.