Mechanism for actuating the throw-off of cylinders using eccentric boxes

A printing unit has a frame and a plurality of printing cylinders, including a first plate cylinder, a first blanket cylinder, a second blanket cylinder mounted in the frame and forming a nip with the first blanket cylinder for receiving a web of material to be printed, and a second plate cylinder. A plurality of eccentric boxes are mounted on the cylinders and supported in the frame. A plurality of actuation assemblies are provided that are connected to the eccentric boxes. One of the actuation assemblies is connected to each of the eccentric boxes for moving the eccentric boxes such that the printing cylinders can be selectively positioned between a thrown-off position and an engagement position in regards to adjacent printing cylinders. Because of the use of eccentric boxes, lower rated and less complicated actuation assemblies can be used.