Drive for rotary-roller offset printing machines

Drive means for a rotary-roller offset printing machine, with arbitrary reversibility of the rotation direction of impression roll means and of plate rolls of the machine, the drive means comprising:

• impression roll means comprising an impression roll;
• a plurality of separate plate rolls for communicating with the impression roll means;
• a respective offset roll for each plate roll and being rotation-secured to the associated plate roll;
• each of the offset rolls being settable to be applied to the impression roll means for rotating together therewith;
• two impression roll gears, each independently and rotatably connected with the impression roll means;
• coupling means for individually coupling one or the other of the two impression roll gears to the impression roll means for rotating therewith;
• a drive for the two impression roll gears;
• a countershaft wheel connected with the drive for being rotated thereby;
• the one impression roll gear engaging the countershaft wheel for being driven thereby;
• an intermediate wheel connected with the countershaft wheel for being driven thereby to rotate in the direction counter to the direction of rotation of the countershaft wheel;
• the other impression roll gear engaging the intermediate wheel for being driven thereby;
• whereby depending upon which of the two impression roll gears is connected with the impression roll means, the direction of rotation of the impression roll means is determined;
• an axle drivingly connected with the plate roll;
• an indexing wheel at that axle and rotatable therewith;
• a sliding gear rotatably mounted for engaging and for rotating the indexing wheel and also being axially slidable for selectively meshing with the one or the other impression roll gear, whereby the direction of rotation of the plate roll is determined by whichever one of the impression roll gears is engaged by the sliding gear.