Patent GB-499800-A (GB)
Title: Improvements in and relating to rotary printing or duplicating machines
IPC: B41L19/00
Filed: 1937-07-30
Abstract: 499,800. Feeding sheets. ADDRESSOGRAPH-MULTIGRAPH CORPORATION. July 30, 1937, No. 21161. Convention date, June 10. [Classes 100 (i) and 100 (ii)] A sheet - feeding device which is especially applicable for feeding sheets to rotary offset printing or duplicating machines is constructed with a feed roller 240 which is carried in oscillating arms 211 adapted to move the roller into and out of contact with the pile so as to withdraw the front edge of the top sheet from beneath spring-pressed hold-down fingers 220 and to buckle the sheet in coaction with an oscillating presser 248. The reverse motion of the roller 240 feeds the separated sheet past guides 250, 251, which bend the front part of the sheet, into the bite of an offset roller 18 and an impression cylinder 75 mounted in a pivoted yoke 53 pressed towards the cylinder 18 by adjustable spring pressure. Thepile table 200 is raised intermittently by means of a pinion 205 engaging a rack 204 attached to a depending part of the table, the pinion being operated by a ratchetwheel 207, Fig. 3, operated by a pawl 208 on a lever 209 depending from the shaft of the feed roller 240, which is carried by a pair of levers 211 which are oscillated. by a cam 118 on the shaft 15 of the offset roller 18. The engagement of the pawl 208 with the ratchet is controlled by means of the fingers 220, which control the position of a lever 215 adapted to engage a pin 216 on the lever 209 to prevent actuation of the ratchet 207 except at such times as the pile needs raising. Reversal of the ratchet is prevented by a spring-controlled pawl 230, which can be released by a pushing member acting on an extension 236 of the pawl when the pile is to be renewed. On exhaustion of the pile, one of the guide rollers 202 on the pile table acts on a spring - controlled lever 270 provided with a latch which normally restrains a freely-mounted cam 272. The cam 272 when released acts to raise the feed roller from the pile and thus the feed is stopped. The feed roller is normally oscillated by a reciprocating rack 243 actuated by a lever 116 on a rock-shaft 115. The shaft 115 is operated by a cam on the shaft 15 and also serves to actuate the messenger rollers of the inking and damping apparatus, such apparatus being described in Specification 499,810. The separated sheet W, Fig. 4, is registered against stops 252 on gripping fingers 300 controlled by springs 308 and a cam 302, and the grippers press the sheet lightly against a bar 306 formed with apertures for receiving the stops 252. The grippers release the sheet as soon as it is gripped by the rollers 18, 75 which act to feed the sheet through the machine and-pull it from the pile. Strippers 320 formed with tines 321 which pass through apertures in the bar 306 detach the printed sheets from the printing-couple and direct them to a receptacle 325. The upper part of the machine is covered by a removable cover-plate 331, and side cover-plates may be used for covering the moving parts arranged outside the machine frame when the machine is not in use. The printing drum is fitted with means for securing the plate in printing position as described in Specification 499,809. Specification 2249 /12, [Class 100 (i)], also is referred to.