Patent GB-800789-A (GB)
Title: Improvements in rotary sheet-fed printing presses
IPC: B41F22/00
Filed: 1957-02-18
Abstract: 800,789. Printing-machines; delivery apparatus. MIEHLE-GOSS-DEXTER, Inc. Feb. 18, 1957 [March 1 1956], No. 5398/57. Classes 100(1) and 100(2) A rotary sheet-fed printing press comprises a plurality of adjacent printing units arranged to print in succession on both faces of sheets, each unit including at least one plate cylinder and an impression cylinder associated therewith, and a plurality of sheet-transfer drums mounted between the adjacent units with their axes in a substantially common plane, in which each of the adjacent units has a plate cylinder with its axis lying in a plane common to all the units, and one unit has a second plate cylinder with its axis located substantially in the plane common to the axes of the transfer drums. As shown, a first printing unit A comprises a frame 10 supporting a plate cylinder 11, inking mechanism 12, and an impression cylinder 13 having grippers 28 to which sheets are fed, from a feed table, by grippers 26. Sheets are transferred to a second unit B by drums 31, 32, and 33 provided with grippers 34, 35, and 36 respectively. The second unit B comprises a frame 14 supporting a plate cylinder 15, inking mechanism 16, and an impression cylinder 17, having grippers 29. Drums 38, 39, 40, and 41 transfer sheets from the impression cylinder 17 to an impression cylinder 22 of a third unit C by means of grippers 42, 43, 44 and 45 respectively. Plate cylinders 19 and 23 having inking mechanisms 21 and 24 respectively co-operate with impression cylinder 22 to print on the reverse side of the sheet to that previously printed. The plate cylinders 11, 15 and 19 are disposed with their longitudinal axes in a common horizontal plane, while the axes of the transfer drums 31, 32, 33, 38, 39, 40 and 41 and the axis of the plate cylinder 23 are disposed substantially in a common horizontal plane, thereby improving accessibility. Delivery apparatus; grippers. The grippers provided on the transfer drums are of similar construction. For example, the grippers 45 and 44 on the drums 41 and 40 respectively comprise a plurality of pads 97 and 101, Fig. 3, co-operating with rockable fingers 98 and 101 respectively. The grippers 37 are recessed within the periphery of the impression cylinder 22 to avoid contact with roller 59, Fig. 2, while the grippers on the drums 41 and 48 are arranged such that their fixed pads 97 and 104 are slightly recessed within the periphery of their drums to avoid tearing a sheet transferred directly from grippers recessed within the impression cylinder periphery to grippers such as 45 and 49, Fig. 1, which hold a sheet tangential to a transfer drum periphery and vice versa. Set-off preventing. The roller 59, Fig. 2, applies a thin film of oil over the tympan 53 on the cylinder to prevent ink from previous impressions, effected by the units A and B, from adhering to the tympan and marking the innermost face of the sheet. The roller 59 is supplied with oil by a wick 58 engaging an intermittently rotated roller 57 contacting a wick 56 dipping in a reservoir 54. The roller 57 is rotated by a pawl 73 on a lever 71 rocked about the shaft 72 by a rod 67 actuated against the action of a spring 74 by a cam 62. The roller 57 and wick 58 are reciprocated axially by an eccentrically mounted roller 83 engaging a bracket 81 which supports the wick 58 on the shaft 72 of the roller 58. The roller 59 is reciprocated axially on the shaft 61 by a pair of arms 86 secured to the bracket 86. The wick 58 can be tripped away from the roller 58 by pulling a rod 88 connected to the bracket 81.