A crop harvester having a mobile frame to be pulled by a tractor and movable between paths of travel at opposite sides of the path of travel of the tractor. The frame includes front and rear longitudinal frame members extending transversely of the direction of travel and a generally central transverse frame member connected to the longitudinal frame members above harvesting mechanism mounted in the frame. A draft tongue has a rear end pivotally connected to the frame on a vertical axis adjacent the connection between the front and transverse frame members, and a front end for pivotal connection to a tractor hitch. A fluid pressure operated device is connected to the frame and to the draft tongue for imparting swinging movements to the draft tongue relative to the mobile frame and for holding the draft tongue in desired set positions of the swinging movement thereof.