An agricultural machine (1), in particular a haymaking machine, for example a rotary rake, the agricultural machine (1 )comprising:- a central frame (2),- at least one carrier arm (3) which being connected to the central frame (2) in such a way that the carrier arm (3) can pivot about a horizontal arm axis (4) in working position,- a working unit (5) being connected to the carrier arm (3) in such a way that the working unit (5) can be displaced, as seen in the longitudinal direction of the carrier arm (3), with respect to the carrier arm (3) for adjusting the position of working unit (5) relative to the central frame (2),- a pressure relief device (6) for applying an upward relief force to the carrier arm (3) in the working position, said pressure relief device (6) being coupled with one end to the central frame (2) and the other to the carrier arm (3),characterized inthat the pressure relief device (6) is designed in such a way that in working position of the agricultural machine (1), the distance between the working unit (5) and the arm axis (4) is positively coupled with the relief force applied by the pressure relief device (6) such that a larger distance induces a larger relief force.
