Patent GB-420374-A (GB)
Title: Improvements in or relating to duplicating machines
IPC: B65H29/56
Filed: 1933-05-29
Abstract: 420,374. Printing-machines. DITTO, Inc., 2243, West Harrison Street, Chicago, U.S.A.-(Assignees of Marchev, A. ; 426, North Spring Avenue, La Grange, Illinois, U.S.A.) May 29, 1933, No. 15476. Convention date, June 13, 1932. [Classes 100 (i) and 100 (ii)] Sheet-delivery apparatus; hectograph-copying apparatus; printing-surfaces.-Relates to a duplicating - machine comprising a rotary printing-drum carrying a duplicating band and having stripping-means mounted within the drum, and consists in providing the band with apertures through which the stripping-means is adapted to project to displace outwardly the end portion of a paper sheet adhering to the band, and thus facilitate removal of the sheet. A gelatine-coated fabric is stretched over an arcuate drum 32, Fig. 5, rotating about a shaft 27 and coacting with an impression roller 168. The ends of the drum are bent inwardly at 35 and 36, and a metallic strip 45 secured to one end of the fabric is hooked over the part 35, a similar strip 45<1> at the other end being hooked over a flange 49 integral with a sleeve 50 adapted to be rotated to draw the band taut. Apertures 34 in the drum allow escape of air from under the band while the band is being fitted. The printed sheets are stripped from the drum 32 by fingers 38 which extend through slots in the member 35 and in the band and are carried by a shaft 201 rocked by means of a member 204 lying in the path of an arm 207 fixed to the shaft, whereby the fingers are pushed outwardly and direct the leading edge of the sheet to delivery rollers 220, 221. When transferring from a master sheet to the gelatine, a shaft 205 is rotated to move the member 204 into an inoperative position and to swing a guide 215 towards the drum to prevent the front edge of the master sheet from being caught by the rollers 220, 221. The sheets delivered by the rollers pass between a guide 250, Fig. 2, suitably curved to remove the curl from the sheets, and guide rods 257 extending into grooves in the roller 221 to prevent the sheets from adhering thereto. A detachable delivery table 240 has pins engaging slots in the machine frame, the forward edge of the table abutting against a bracket in which the rollers 220, 221 are mounted. Feeding sheets.-A pile of sheets 74 is laid on a feed-table 73 having a pivot pin 75 at each side engaging a slot 76 such that the table overbalances to the right. At each rotation of the drum 32, the pile is raised into contact with a rotary feed roller 71 by a rod 78 fixed to a shaft 79 carrying a gear segment 90, which is rocked counterclockwise by a pawl 91 carried by a lever 92 engaging a cam 96 on the drum and is then released, whereupon a spring 110, adjustable in tension, rotates the segment through an angle depending on the thickness of the pile of sheets. The front edge of the pile beam against an inclined plate 120 carried by an angularly adjustable shaft 161 and bent rearwardly at 122 to prevent advance of more than one sheet. A margin bar 116 carried by an arm 170 connected to a cam-actuated lever 176 temporarily projects into a gap 33 in the drum, and a plate 136 fixed to a cam-actuated shaft 137 clamps the sheet against an extension 134 of the member 120 after its advance up to the margin bar, and subsequently separates slightly to guide the sheet in its advance during printing and then separates widely to allow free advance of the next sheet. For feeding by hand, the feed-table 73 is lowered and the plate 136 is raised to inoperative positions by rotating an eccentric 152 engaging the rod 78 and an arm 150 fixed to the shaft 137. When transferring from a master sheet, a plate 269 pivoted to brackets fixed to the shaft 27 is moved to the broken-like position, Fig. 5, to form a margin bar. Counting - apparatus.-A counter 194 is actuated from the lever 176.