A timepiece mechanism including a deformable rhombus including four coplanar segments pivotally connected in pairs by their vertices, including an input segment adjacent to an output segment, both pivoted about a pivot axis perpendicular to the plane of the rhombus and passing through a first vertex common to the input and output segments and locked in translation in the plane of the rhombus, a lever mounted to pivot about the pivot axis, the lever being kinematically connected in rotation, about the pivot axis, to a second vertex of the rhombus, opposite to the first vertex, a first locking member movable between a first locking position, in which the lever is locked in rotation, and a first unlocking position in which the first locking member does not hinder rotation of the lever, a second locking member movable between a second locking position, in which the second vertex is locked in translation in a radial direction, and a second unlocking position in which the second locking member does not hinder radial movement of the second vertex.

A horological mechanism (110), notably a horological movement or chronograph module, including a counting chain (100) having an epicycloidal train (31, 32, 33, 34) including a first sun wheel (33) fixed to the frame.

Timepiece torque variator mechanism for regulating the torque ratio between a first path extending about a first pivot axis, and a second path about a second pivot axis, this mechanism comprising an intermediate wheel set, forming a planetary wheel, simultaneously cooperating in a first contact area with this first path, and in a second contact area with this second path, and control means arranged to adjust the radial position of the first contact area with respect to the first pivot axis, and/or to adjust the radial position of the second contact area with respect to the second pivot axis.

Timepiece movement including a date display drive device formed of a display disc including a toothing, said drive device including driving means and a drive source. The driving means includes a wheel set including pins, having a toothed wheel and a pinion including pins, and an engaging wheel engaging said toothed wheel. The pinion with pins includes a pair of pins configured to be positioned on either side of any tooth of the toothing. The toothed wheel of the pin wheel and the engaging wheel respectively have complementary non-circular profiles. When the two pins are oriented in a tangential direction to the toothing, these two wheels have a first gear ratio that is lower than a second gear ratio between them when the two pins are in perpendicular alignment to said tangential direction.