GB911855A - Tension lock-up for thin printing plates - Google Patents

Abstract

911,855. Printing machines. MIEHLE-GOSS-DEXTER Inc. Feb. 28, 1961 [March 7, 1960], No. 7294/61. Class 100 (2). A thin printing plate 16 having turned-over edges 16a, 16b, is secured to a cylinder 15 by plate-securing means housed in a slot 24. The means comprise a series of U-shaped spring elements 26 which are secured in the slot to an L- shaped block 30. The latter is mounted at each end through pips 35, 36 which engage a plate 34 adjustably attached to the associated end of the cylinder 15 by bolts 38 threaded into tapped holes in the cylinder and passed through slots 39 in the plate. Rigidly fixed to the cylinder end is a collar 40 rotatably journalling a screw 41 extending for threaded engagement into a tapped opening 42 in the plate. By turning the adjusting screws 41 at the opposite ends of the cylinder 15 by equal or different amounts the block 30, and hence the spring elements holding the printing plate, may be adjusted either to move the printing plate circumferentially or to skew it. Each spring element 26 has jaws 26d, 26e which in their normal or relaxed position close on each other thereby drawing the printing plate with which they are engaged through the edges 16a, 16b, tightly around the cylinder. In order to release the plate the jaws are forced apart by rotating a shaft 28 which is rotatably mounted in the slot 24 within the spring elements 26 and is formed with a flat 28a such that it has maximum and minimum dimensions " m " and " n." The shaft is mounted in circular openings 44 in the plates 34 and has squared ends 28b received in squared openings cut in control members 45, 46. Rotation of the shaft is restrained between two angular limit positions by engagement of the pin 36, which projects from each plate 34, with the associated member 45 or 46. Such restraint ensures that the shaft is always turned counterclockwise to spread the jaws 26d, 26e. The shaft may be turned by hand through applying a wrench to the squared ends 28b or such movement may be automatically applied through the engagement of a bolt 50 projecting from the member 45 with a stud 51 which is mounted on the associated end of a cylinder such as a blanket cylinder 20 which rotates in contact with the printing cylinder. Such automatic release of the elements 26 from their plate unlocking position, Fig. 7, to their locking position, Fig. 8, ensures that the plate is secured to the cylinder 15 when the adjacent cylinder 20 is holding the trailing end of the plate over the whole cylinder length. The plate securing means may be used to fix paper plates 55 to the cylinder in which case a slot 28d, Fig. 12, is formed in the shaft to hold the trailing edge 55b of the plate. In another embodiment, the spring elements are in two parts, the jaws 26e<SP>1</SP>, Fig. 13, being carried on arms 26c<SP>1</SP> bolted to the block 30<SP>1</SP> whilst the jaws 26d<SP>1</SP> are secured directly to the front edge of the block. A single spring element extending the length of the slot may be used instead of the plurality of shorter elements.