Patent GB-640482-A (GB)
Title: Printing apparatus
IPC: B41L47/24
Filed: 1948-01-08
Abstract: 640,482. Printing-machines; feeding sheets. ADDRESSOGRAPH-MULTIGRAPH CORPORATION. Jan. 8, 1948, No. 621. Convention date, April 2, 1947. [Classes 100 (i) and 100 (ii)] A series printing machine is fitted with an automatic feeding mechanism, which includes automatic sheet separating and advancing mechanism, and is constructed so that the automatic operation may be suspended to permit of hand feed, and permits the automatic feed to be resumed without necessity of readjustment of the mechanism. A mechanical driving and timing connection between the printing and sheet separating mechanism is so arranged that the sheet separating mechanism may be swung out of and into connection with the sheet advancing mechanism without breaking such driving and timing relation, and this permits of the rernoval of undesired or clogged sheets, and permits removal of the sheet advancing means, and so renders the table top of the printing- machine accessible for hand feed without severing the driving connection between the separator and printing- machine. The invention permits multiple impression work at relatively high speeds. The invention is described as applied to a printing- machine 10 of the kind described in Specification 558,793 in which printing-plates are advanced from the bottom of a magazine 15 to a table top 18 into register with a platen 16, the printing-plates being of the kind described in Specification 489,390, and the platen 16 is supported above the table top 18 by a printing frame 20 constructed as in Specification 555,821. The platen mechanism is of the kind described in Specification 555,033. The printing mechanism is driven by a motor 31 controlled by a switch 33 arranged in one of the panels of the printing-machine, and the motor drives by belts 35, Fig. 17, and a pulley 36 free on a shaft 37 which is driven by means of a one-revolution clutch to drive the feed and printing mechanisms. The shaft 37 is connected bv bevel gearing 217, 218, 219, to a shaft 220 which drives the sheetseparating mechanism, and the framework which carries the sheet-separating mechanism can be moved about the axis of the driving-gear 218 so as to move the separating-mechanism and part of the sheet forwarding mechanism to the position shown in Fig. 4. A rod 212 pivoted about the axis of gear 218 is connected to the frame and assists the pivotal movement of the frame which is provided with wheels 64 to assist the withdrawal of the separating- mechanism. The driving-connection between the printing and separating mechanism is not broken upon movement of the separating- mechanism. The drive of the motor 31 is controlled by an auto-stop control plunger 46, Figs. 1 and 24, as described in Specification 558,793, and in Fig. 24 the electrical circuit is shown which comprises an electromagnet 47 which when the last printing-plate is fed, actuates the plunger 46 and opens the circuit of the motor 31. The electrical diagram, Fig. 24, also shows circuits for controlling the energization of a motor 128 which drives the suction separating mechanism, and for operating the plunger 46 to stop the motor 31 if doublefeed occurs, or if a sheet fails to be fed correctly. The printing operations may be controlled by sensing means acting in conjunction with identifying means on the printing-plates as described in Specification 560,570. The means for advancing the separated sheets over the table 18 and registering them in printing position are preferably such as described in Specification 560,597, and are mounted on a bridging structure 59, Fig. 1, connecting legs 57, 58 mounted on wheels 60 which permit withdrawal from the table 18 and the separating- mechanism, so that sheets may be fed by hand over the table 18. Normally the frames of the devices are held together by adjustable locking devices which are released when the parts are to be withdrawn. The sheets are fed from a stack 61, Fig. 7, supported by counterweighted chains 77, and are separated by means of suction members 72 all as described in Specification 630,336 including means for controlling automatically the raising of the pile and for assisting separation of the sheets by air blasts from a pipe 161. The separated sheets are forwarded by pairs of rollers 138, 139; 163, 164; 166, 167, between which are sheet guides, and associated with which are feeler devices for stopping the machine if the sheets are not fed correctly. The feed rolls 139, 164, 167 are narrow rolls and are adjustably mounted for dealing with sheets of different thicknesses and widths. To permit of single or multi-impressions for each actuation of the printing mechanism the shaft 220 which is driven by bevel-gearing from the printing- machine drives by gears 226, 229 a shaft 230, Figs. 4 and 7, which is connected by a changespeed gear 234, with a shaft 233 geared to a gear 237 freely mounted on the shaft 230, the gear 237 being fitted with a crank-pin which by means of a connecting-rod actuates the operating lever of the sheet-feeding mechanism. As a sheet can receive from one to four impressions four sets of rising front stops are provided, and are operated so that the sheet can be registered in from one to four positions corresponding to the setting of the change-speed gears. The sheets are fed to printing position by belts 327, Fig. 4, which are driven by the shaft 233 via gears 296, 295 which drive a gear 348 when the separating mechanism is moved from the position shown in Fig. 4 into active position. To stop the machine if double-feed occurs, a deflector in the form of a hooked plate 243 is arranged between a pair of upper feed rolls 139, Fig. 7, at a distance above the roll 138 to permit the passage of a single sheet. The detector is connected by a link to a lever fitted with an adjusting screw 256 which closes a switch 251 when double-feed occurs. As shown in Fig. 24, the switch 251 is in a parallel circuit to the switch 52, and when closed energizes the magnet 47 and so operates the plunger 46 to stop the machine. The switch 251 is also closed to stop the machine if no sheet is fed. A groove is formed in the lower feed roller 166 and if a sheet is not present between the groove and an upper sensing roller 272 the lever 273 in which the roller 272 is mounted drops and actuates the switch 251 by means of a link 276. This mechanism is controlled by a timing mechanism which limits the. action of the sensing roller 272 to the period when a sheet should be gripped by the rollers 166, 167. At other times the roller 272 is held in raised position by a lever 286 operated by linkage from a cam 278, Fig. 7. The linkage comprises a lever 281 to which is adjustably connected an outer arm 282 by means of screws passing through a slot in the arm 282 which carries a roller 280 engaging the cam 278. The feed rollers 138, 163, 166, are driven by a belt deriving its motion from roller 166 which is connected by gears to a shaft 293, Fig. 7, driven by a belt 291 from the suction pump which controls the suction feed. This pump is driven by an electric motor 128 indicated in the circuit diagram, Fig. 24. A switch 311 permits the sheet separator to be actuated independently of the printing mechanism, and controls an electromagnet 317 which releases a one-revolution clutch for driving the separator. A switch 323 is in series with the detector 251 previously described and effects a similar control..The switch 309 controls connection of the motor 128 to the power lines 301, 302. The feed rolls 166, 167, direct the separated sheets to an adjustable guideway 326, Fig. 7, and thence to above the plane of the bridge structure 59 to printing position, by means as described in Specification 560,597, and the sheets are finally delivered to a receptacle 329. When a sheet is to receive multiple impressions, a number of sheet stops 328, Fig. 2, not shown, are adapted to stop the sheet in the required positions, and these are controlled by mechanism such as is described in Specification 560,597. The stops are controlled by a cam-shaft 400, Fig. 1, coupled to a shaft 412 which is driven from the separator by mitre gearing including a gear 405, Fig. 4, which when the separator is restored to active position engages a gear 409 geared to the shaft 400. Specifications 238,547 and 248,785, [both in Class 100 (i)], also are referred to.