A towed agricultural implement including a main chassis member, a moveable arm for carrying at least one working implement located to each side of the main chassis member, each moveable arm being moveable between a working position and a transport position, the main chassis member having a support device for attachment to a towing vehicle, the support device having left and right lower attachment points for attaching to lower mounting points of a three point hitch of a towing vehicle and a central upper attachment point for attaching to the upper mounting point of the three point hitch, in which each left and right attachment point is mounted on an articulated arm connected to the main chassis member, the main chassis member further including a regulating control apparatus to secure and release a free end of each articulated arm in an operative position. This construction has as an advantage that on encountering an obstacle the articulated arm can be released allowing the working implement to move away from the obstacle.