Abstract: A roll baling machine includes a main frame, a tailgate pivotally connected to the main frame, and an apron extending around a plurality of guide rolls disposed in the main frame and in the tailgate. A pair of take up arms are rotatably mounted in the tailgate and carry an additional guide roll for the apron. A pair of levers are connected to rotate with the take up arms, and springs are connected to the levers to urge the take up arms into a bale starting position. The machine is provided with a twine wrapper, and a mechanism for automatically tripping the twine wrapper into operation comprises a cam surface on one of the levers engageable with a cam roller carried on a first link. This first link is rotatably mounted on the main frame and is connected to a sliding member which is movable toward and away from a tripping position. The tripping mechanism also includes second, third and fourth links connecting the first link to the sliding member.