Zero-resetting device for two time counters

A device for the simultaneous zero-resetting of two time counters, especially of a chronograph, the pivot axes of which are fixedly connected to respective heart-shaped zero-resetting cams (7, 8), comprising a zero-resetting lever (2) containing two hammers (6c, 6d), means (5) for exerting selectively upon this lever (2) a torque for pressing the two hammers (6c, 6d) against the respective zero-resetting cams (7, 8), and articulation means (2d, 2e, 6a, 6b) for articulating these hammers relative to the zero-resetting lever (2);

• in which the force generated by said torque is essentially directed toward a first (7) of the zero-resetting cams, wherein the articulation means comprise two pins (2d, 2e), a first of which (2d) is engaged in a guide slot with limited displacement amplitude (6a), orientated so that, in the zero-resetting position, the force (F1) dropped perpendicularly from the axis of the first pin (2d) onto this guide slot (6a) intersects the straight line joining the axes (7a, 8a) of the zero-resetting cams (7, 8) at a point closer to the second of said cams (8) than is the point of intersection on this same straight line of the direction of the force exerted upon this first pin (2d) by said torque, and the second pin (2e) of which is engaged with play in an opening (6b) to allow a limited rotation of said hammers (6c, 6d) about the axis of the first pin (2d) so as to ensure a simultaneous contact of the hammers (6c, 6d) with the two shoulders of said respective zero-resetting cams (7, 8).