Patent GB-846610-A (GB)
Title: Improvements in or relating to rotary printing machines
Inventor: CHEESEMAN LESLIE HARRY
IPC: B41L19/00
Filed: 1958-01-28
Abstract: 846,610. Feeding sheets. ADDRESSOGRAPH-MULTIGRAPH Ltd. April 28, 1958 [Jan. 28, 1958], No. 2872/58. Class 100(1) Sheet-separators:- In apparatus for feeding sheets from the top of a pile to a rotary printing machine by suction pads, the latter are arranged to move with a slide which is driven and guided so that it moves upwardly along a first guideway and enters a recess in a block in a second intersecting and horizontal guideway, and then moves with the block along this second guideway, whereby the suction pads first lift a sheet vertically, and then carry it horizontally towards the printing rollers. As shown in Fig. 1 applied to a rotary duplicator, sheets are fed between an offset cylinder 4 and impression roller 5 by feed rollers 6, 7, the cylinder 4 co-operating with a master cylinder 1 which is inked by a roller 3. Sheets 11, supported on a table 10 which is raised by rack and pinion means 12, 13 under the control of a feeler which tests the height ot the sheet pile, are separated by two suction pads 14 each carried by a foot 15 fixed on a cross-shaft 16 and the pads 14 follow a vertical and horizontal path 30.'An extension 21 of an eccentric strap 20, on an eccentric 19 secured to the shaft 18 of the cylinder 4, has a slotted end engaging a pin on a lever 23, pivoted at 24, whereby the lever 23 is oscillated. The lever 23 is connected by arms and links to the shaft 16, and this arrangement is duplicated at the other side of the machine. Each lever 23, Fig. 2, rocks an arm 48 about its pivot 49 by means of a curved link 34 which is notched to engage a pin 47 on the arm, and links 51, Fig. 5, on the arms carry the sucker shaft 16. One end of the shaft 16 carries a roller which operates in a shaped groove in the machine frame, and the other end carries a square slide 53 which is guided so that it first moves upwardly in a vertical guideway to enter a recess in a block 59 (not shown), and then moves with the block along a horizontal guideway. The notched link 34 is normally held in engagement with the pin 47 by a roller on an arm 39, Fig. 2, which is connected to a pivoted arm 40 controlled by a manuallyoperahle link 44 which thus controls the sheet feeding operation. Control of vacuum at the suction pads 17 is effected by opening the pipe line to atmosphere at the appropriate times by a link 115 (not shown), connected to one arm 48, which has a lug adapted to tilt a pivoted bracket carrying a valve which opens and closes the pipe line opening. The delivery side of the suction pump is connected to deliver air jets directed towards the front top edge of the sheet pile, and other air jets towards the top front corners of the sheet pile. The rear side edges of the sheets 11 are weighted by fingers 137, Fig. 5, on levers 136 fixed on a shaft 132A which has its ends provided with bearing blocks 133 mounted in frame guideways 134. Pile tables:-Side members 66 are adjustablysecured above the pile table 10, Fig. 5, and a back stop 72 is carried by a swingable bracket 75, to locate the sheet pile, the bracket and side members being carried by the table on a cross-shaft 65 thereon. The table is supported on end brackets 80 having rollers 81 engaging vertical frame slots 82, each bracket having a rack 12, Fig. 1, engaged by a gearwheel 13 secured to a shaft 84 provided with a ratchet wheel 85 which is normally secured to the shaft, but can be released on depressing a knob 86 to allow the shaft to be rotated by the knob. When the arm 48, Fig. 5, is rocked clockwise during the feeding of a sheet it moves a drive link 97, connected thereto, from left to right so that a tongue 107 on the link rocks a pivoted arm carrying a pawl slightly clockwise but not sufficient to advance the ratchet wheel 85 one tooth pitch. During this movement, a cam 89 fixed to a shaft 88 is turned counterclockwise by a latching pawl 100 carried by the link 97, and pile feeler blade (87, not shown) carried by shaft 88 lifts from the pile to allow the top sheet to be separated. Also, towards the end of this movement, a trip pawl 105 disengages the latch pawl 100 from the cam 89 which now swings counterclockwise, under the action of a spring, towards a pawl 113. If the top of the pile is high enough, the feeler blade engaging the pile arrests the movement of the cam 89 before it encounters the pawl 113. When the top of the pile is not high enough, the cam 89 strikes the pawl 113 which disengages from a tooth on the pivoted arm which carries the pawl actuating the ratchet wheel 85, and this arm swings back so that the pawl engages behind the next tooth on the wheel 85. During the next left to right movement of the link 97 the ratchet wheel 85 is advanced one tooth pitch, and the table 10 is raised. A pawl 108 retains the wheel 85.