GB848731A - Improvements in or relating to sheet feeding devices for platen printing presses - Google Patents

Abstract

848,731. Feeding sheets; platen printing machines. SCHNELLPRESSENFABRIK AKTIENGESELLSCHAFT HEIDELBERG. Feb. 25, 1958 [Dec. 24, 1957], No. 5991/58. Classes 100(1) and 100(2) In a sheet feeding apparatus for a platen printing press wherein a vertically reciprocating suction bar separates sheets from the top of a pile and an intermittently rotating gripper bar transfers the separated sheets to the platen, control means is provided whereby the source of suction to the suction separator bar cannot be cut off, so that the separated sheets are still held in contact with the suction bar during their transfer to the platen by the gripper bar, and are thus kept taut. The control means facilitates a more speedy feeding of flimsy sheets which would be creased when fed at high speed in a press where suction to the suction separator bar is cut off immediately the sheets are gripped by the gripper bar. As shown, the press 1 has an oscillating platen 2 and a vertical forme 9, and a pile of sheets 5 is supported by a table 4 mounted in a frame bracket 3. Sheets are separated from the pile by a vertically reciprocating suction bar 6 provided with nozzles 7, and they are transferred to the platen 2 by a rotating gripper 8 mounted thereon. The suction bar 6 is reciprocated by a cam-controlled lever 10, which also reciprocates a control member 11, Fig. 3, having a roller 17 thereon which runs over a cam face 18 on the press to control the opening and closing of a flap valve 15. When the valve 15 is closed, suction is established at the suction bar 6 through a pipe 12, a passage 24 in the member 11, and a pipe 13. When the valve 15 is open, normally the. passage 24 is open to atmosphere through a passage 14 in the member 11, and thus the suction bar 6 is rendered inoperative : this occurs, when feeding normal sheets, when the gripper 8 takes a sheet from the suction bar. When feeding flimsy sheets, a slide 23 can be moved manually to close the passage 14 to render the valve 15 inoperative, in which case suction is always established at the suction bar 6. A further slide 20 can be moved manually to open the passage 24 to atmosphere through a passage 19 to render the suction oar 6 inoperative. The control cam 18 or the roller 17 may be moved or adjusted into an inoperative position by a control member, so that the valve 15 is not actuated.