A system (1) for resetting a chronograph is provided with a chronograph counting geartrain (2), which includes a minute counter having a minute wheel set (4), and a seconds counter, which includes a chronograph wheel set (3). The system includes a hammer held blocked by blocking device (11) and displaceable from an inactive position, where the hammer is blocked by the blocking device, and an active position, when the hammer is unblocked, for resetting the chronograph in contact with the various wheel sets (3, 4); a flexible element (10) connected between a reset controller (12) and the hammer for resetting the chronograph, and configured to store energy during a displacement of the controller and before unblocking the hammer blocked by the blocking device to be able, when the hammer is unblocked, to restore this stored energy and drive the hammer to reset the chronograph.

A system (1) for resetting a chronograph is provided with a chronograph counting geartrain (2), which includes a minute counter having a minute wheel set (4), and a seconds counter, which includes a chronograph wheel set (3). The system includes a hammer held blocked by a blocking means (11) and displaceable from an inactive position, where the hammer is blocked by the blocking means, and an active position, when the hammer is unblocked, for resetting the chronograph in contact with the various wheel sets (3, 4); a flexible element (10) connected between a reset control means (12) and the hammer for resetting the chronograph, and configured to store energy during a displacement of the control means and before unblocking the hammer blocked by the blocking means to be able, when the hammer is unblocked, to restore this stored energy and drive the hammer to reset the chronograph.

A device for counting a number of time unit fractions or a number of movement unit fractions of a mobile member (1; 6; A2), the device a first including (i) a first cam (1) having a first surface (10: (ii) a second surface (20), the second surface being an abutment surface; (iii) a mobile support (4) urged by a spring (R4); (iv) a mobile pawl (3) mounted on the support (4) and urged by a spring (R3) toward the first surface, the pawl (3) being adapted to cooperate with one or the other of the first and second surfaces (10, 20) according to the position of the support (4); and (v) a control system (80) adapted, in a first or non-counting state of the control system, to maintain the support in a first position and, in a second or counting state of the control system, to allow the movement of the support.