Patent GB-748058-A (GB)
Title: Improvements in or relating to flat bed platen printing presses
IPC: B41L15/02
Filed: 1954-04-28
Abstract: 748,058. Printing-machines. McLAUGHLIN, H. R. April 28, 1954 [July 1, 1953], No. 12310/54. Class 100 (2). Platen machines.-A platen printing-machine for letterpress printing comprises a horizontally disposed paper-supporting platen 4 mounted for horizontal reciprocation in the frame 1 from an outward paper-feeding and withdrawal position into an inward printing position in which it is located under a flat bed 5, Fig. 4, on which the type 8 is mounted, the bed 5 being pivoted to the frame at 13 for movement into and out of contact with the platen 4 for the printing operation, after which the platen is reciprocated back to its original outward position permitting withdrawal of the printed sheet and feeding of a fresh one. The frame 1 is of I-section, the side flanges being provided with runners 2, Fig. 7, carrying the platen 4. The bed 5, near the free end, has a cross-pin 16 connected by a link 17 at each side to pivot pins 18 near the end of operating lever arms 19. Arms 19, connected by an operating handle at one end, are adjustably fixed at the other to a cross shaft 22 passing through the lower side flanges of the frame. Downward movement of the arms causes the bed to swing down to force the type 8 carried thereon into contact with the paper on platen 4. The bed 5 also carries an ink-distributing plate 9 movably carried on headed pins 12 and spring-loaded to the outer position. The upper side of the bed 5 is covered by a cover 6. One of the nuts 21 at the ends of cross pin 16 may readily be removed and the pin withdrawn so that the bed 5, released from links 17, may be swung over to lie in line with the frame 1. This facilitates the positioning and attachment of the type 8 in chase 7. The rotation of the handle shaft 22 caused by operation of arms 19 is transmitted by a torsion spring 35, Fig. 7, to an arm 24 freely mounted on the shaft and projecting upwards through a slot 25 in the web of the frame 1. The arm 24 is connected by a system of links and levers to cause longitudinal oscillation of the platen 4, the final lever 30 being connected by a link 32 to a pin 33, Fig. 4, projecting downwardly from the underside of the platen. In its outermost position the platen is limited by engagement between the pin 33 and a stop 34 having a resilient facing. In operation initial movement of the lever arms 19 from the vertical position displaces the platen towards the outer position but does not displace the bed 5 because of the substantially arcuate movement of the end of links 17. After the platen has reached its limiting position continued rotation of shaft 22 merely stresses spring 35. Towards the end of the operating stroke the lever arms 19 cause the bed 5 to be drawn downwardly against the platen the printing pressure being adjustable by limiting stops 56 for the arms. Reverse movement of the arms is transmitted directly through shaft 22 to the arm 24 and is assisted initially by the spring 35. The frame 1 has rubber feet 55. Drawers to receive copy-sheets may be provided under the web of the frame in front of and behind the cross shaft 22. Alternatively the rear end may be closed by a piece of sheet metal 54. Inking mechanism.-Ink is applied initially, by hand, to a roller 36 carried on a bracket 37 on arms 39 hinged to the underside of the platen. A cross-bar 38 of the bracket slides on inclined ramps 41 secured to the web of the frame. The ramps are parallel to the bed 5 in its open position. During inward movement of the platen the roller first rolls over the yieldable distributing plate 9 and then over the type surface 8. In the printing position the bracket 37 rests on the web of the frame and the roller is out of the way of the bed 5. Side lugs 44 on plate 9 engage the platen 4 as the bed descends and keep the plate out of contact with the sheet being printed.