Patent GB-189730770-A (GB)
Title: Improvements in Lithographic Printing Machines for Printing upon Sheet Metal and other Materials which are Difficult to Bend, or if Brought against the Stones or Substitutes therefor used in such Machines would cause Injury to such Stones or Substitutes therefor, or to the Printing Surfaces thereon.
Inventor: KIRKBRIDE JOSEPH
Filed: 1897-12-30
Granted: 1898-12-03
Abstract: 30,770. Kirkbride, J. Dec. 30. Lithographic printing.-Relates to lithographic machines for printing upon sheet metal, tiles, glass, &c. The machine is to a great extent similar to an ordinary two-colour letterpress printing- machine, and is provided with inking and ink-distributing rollers v, u, damping-distributing rollers w, and inking-slabs t<1> &c. The carriage a receives motion from the shaft f by means of the rod e and the wheel g which gears in a rack h fixed to the machine and a rack i upon the carriage. The carriage a imparts motion to the cylinder p by racks and pinions arranged so that the cylinder is rotated only when the carriage is moved in the direction indicated by the arrow A. The carriage is supported by rollers j coupled together and connected to the axle of the wheel g by a link o. The cylinder revolves twice during the movement of the carriage, and is provided with a suitable braking- mechanism. A lever s and weight s<2> press the cylinder to its work. The carriage a is provided with a lithographic stone b, or substitute therefor, and a printing bed or surface y. The cylinder p is covered with india-rubber so as to receive impressions from the stone b and transfer them to the metal &c. which is placed on the bed y. A shaft 2, Fig. 2, is mounted upon the carriage a and carries gripper-fingers 3 with upper jaws 3<a>, to act in conjunction with a metal bar on the bed y and hold the metal sheets &c. in position, and with lower jaws 3<b> to enter notches in the bar and raise the metal sheet &c. An arm 4 is attached to the shaft 2, and is operated by means of cams 6, 7. The cam 7 is fixed upon the side frame m. The cam 6 is fixed upon a bar 8 capable of being raised and lowered by an arm 9 and other link work operated by a cam on the shaft f. The cam 6 serves to lift the gripper-fingers 3 so that the metal sheet &c. may be inserted, and the cam 7 serves to lift the lower jar 3<b> of the fingers and raise the material. A shoot or guide 16 is mounted upon an axle 15 mounted in the standards 14, upon and from which the metal sheets &c. are transferred from the table 17. By means of the bar 8, which is duplicated upon the other side of the machine, the guide 16 may be raised in line with the plate 19 so that the metal sheets &c. shall be in proper register when transferred to the bed y. When the carriage a begins to move in the direction indicated by the arrow A, the guide 16 is lowered and the metal sheet &c. laid upon the bar of the printing-surface y. The gripper-fingers 3 act in conjunction with the bar and secure the sheet as it is drawn under the cylinder p. Near the end of the travel of the carriage, the cam 7 causes the lower jaw 3<b> to raise the metal sheet, which is caught by the fingers 20, up which it slides to the revolving band 24 by which it is carried away. Projecting ribs on the bed push the sheet up the fingers 20. In operating the machine, an unprinted sheet first passes through, in which operation the roller p receives an impression, and during each subsequent to-and-fro motion of the carriage one impression is transferred from the stone to a sheet. The gripper-fingers may extend across, or nearly across the printing-bed, and the projecting ribs on the bed may consist of spring-pressed studs. The stone or equivalent may be arranged to pass beneath the cylinder before the printing-bed.