Knotter system for a baler

A baler comprising a plurality of knotter systems, each of the plurality of knotter systems for performing a knotter cycle of the baler, the knotter cycle having at least a first knot forming cycle and a second knot forming cycle, each of the plurality of knotter systems comprising:

• a needle configured for delivering a needle twine;
• a tucker arm configured for delivering a tucker twine;
• a billhook assembly comprising a billhook having a lower lip and an upper lip mounted pivotally with respect to the lower lip, the billhook being mounted rotatably around a rotational axis;
• and
• a driver adapted to make the billhook perform at least a first full rotation around its rotational axis during the first knot forming cycle and a second full rotation around its rotational axis during the second knot forming cycle,
• wherein the billhook assembly is configured to move the upper lip away from the lower lip in a first angular range and to move the upper lip away from the lower lip in a second angular range of at least one of the first full rotation and the second full rotation,
• wherein the first angular range is located within a range between 0° and 160°, and
• wherein the second angular range is located within a range between 160° and 360°,
• wherein, for each of the plurality of knotter systems:
• the billhook assembly further comprises a cam surface,
• the billhook further has a cam follower in contact with the cam surface, and
• the cam surface has a first cam and a second cam configured for pushing the upper lip away from the lower lip, in the first angular range and in the second angular range, respectively, during the first full rotation and during the second full rotation.