Chronograph mechanism and method for assembling a chronograph mechanism

A chronograph mechanism for a horology movement comprising a zero reset mechanism comprising:

• a first hammer and a second hammer configured on two levels to respectively engage with a first zero reset organ on a first chronograph counter and a second zero reset organ on a second chronograph counter that are not coplanar;
• the first hammer and the second hammer pivoting separately relative to each other around at least one axis of rotation;
• a resilient coupling organ, arranged between the first hammer and the second hammer, which has an operating position in which a first bracket bears on the first hammer and a second bracket bears on the second hammer;
• wherein said zero reset mechanism comprises:
• a preliminary support organ for the resilient coupling organ arranged on the second hammer and configured to support said first bracket on the resilient coupling organ in a pre-assembly position;
• a clip-on organ, secured to the first hammer, configured to engage with the first bracket on the resilient coupling organ and move said resilient coupling organ into its operating position in which the first bracket bears on the clip-on organ to ensure rotationally elastic coupling of the first hammer and of the second hammer during a relative axial displacement between the first hammer and the second hammer in a direction parallel to the at least one axis of rotation, when the assembling the hammers.