Gripper bar conveyor for multiple color offset rotary printing press

A gripper bar conveyor mechanism for transferring sheets to be printed from one rotating impression cylinder to another in an offset printer of the type having a plurality of sets of impression cylinders and corresponding blanket cylinders for rolling contact with the sheets to be printed therebetween, said gripper bar conveyor mechanism comprising:

• a) a transferrable gripper bar activatable for releasably securing sheets to be printed in a fixed orientation with respect to said transferrable gripper bar;
• b) a registration projection affixed to said transferrable gripper bar;
• c) a registration pocket affixed to each of said impression cylinders for temporarily receiving said registration projection and holding said affixed gripper bar in a desired position with respect to each of said impression cylinders while rolling contact of the sheet to be printed is initiated between each of said impression cylinders and said corresponding blanket cylinders;
• d) an exit guide roller attached to said transferable gripper bar;
• e) an exit guide surface attached to said offset printer adjacent said impression cylinder positioned for contacting said exit guide roller and lifting said projection out of said registration pocket after rolling contact of the sheet to be printed is initiated;
• and
• f) a conveyor band attached to said gripper bar and operably connected to said rotary offset press for transferring said transferrable gripper bar from one impression cylinder to said another impression cylinder so that said registration projection is engaged in said registration pocket at each impression cylinder during a portion of the impression cylinder rotation sufficient to initialize rolling contact of said sheet to be printed in proper registration between each of said impression cylinders and said corresponding blanket cylinders.

A straight through transfer pickup mechanism for use with a gripper bar conveyor mechanism to grasp, without bending, a printed sheet from a printing section of an offset printing press, said transfer pickup mechanism comprising:

• a) a transferable gripper bar activatable with a cam and cam follower arm for releasably securing sheets to be printed in a fixed orientation with respect to said gripper bar;
• b) a continuous conveyor band operably attached to said gripper bar for horizontally moving said gripper bar through said printing section with a releasably secured sheet to be printed and for returning to secure another sheet around a return roller;
• c) a continuous transfer band carrying a transfer gripper which has an overlapping path portion, at which said transfer band moves above and parallel to said horizontally moving conveyor band downstream from said printing section and upstream from said return roller;
• d) parallel gripper bar slide surfaces for holding said gripper bar in a horizontal orientation as it moves adjacently parallel to said overlapping path portion of said transfer band;
• e) a cam positioned at said overlapping section for actuating said gripper bar to release said secured sheet;
• and
• f) means for actuating said transfer gripper to grasp said sheet in said overlapping section immediately prior to said release of said printed sheet.

A gripper and conveyor mechanism for moving sheets to be printed in a rotary offset printer from one set of printing cylinders to another set until printing is completed at each set of cylinders, said gripper and conveyor mechanism comprising:

• a) a movable gripper bar activatable for securing a sheet to be printed in a single fixed orientation with respect to said movable gripper bar at a first set of primary cylinders and for holding said sheet until printing is completed at each set of printing cylinders;
• b) a registration projection rigidly connected to said movable gripper bar;
• c) a registration pocket affixed to one cylinder of each set of printing cylinders for repeatably receiving said registration projection and holding said movable gripper bar in proper registration while printing of said held sheet is initiated at each set of cylinders;
• d) a conveyor operably attached to said gripper and synchronized with said printing cylinders for moving said gripper bar from one of said sets of cylinders to the next so that said registration projection is repeatably received in proper registration in said registration pocket at each of said sets of printing cylinders;
• e) a horizontal conveyor band slide guide for slidingly guiding said moving conveyor band with said gripper bar attached to said conveyor band from one of said sets of printing cylinders to the next in a horizontal path tangentially adjacent each cylinder with said registration pocket for registration and printing of a sheet to be printed;
• and
• f) a return conveyor band guide including a roller spacing said conveyor band and gripper bar away from one or more of said printing cylinder sets, as said gripper bar is returned to said first set of printing cylinders, thereby avoiding registration with each printing cylinder set on the return trip.