Patent GB-733262-A (GB)
Title: Improvements in or relating to sheet feeding devices for rotary duplicating machines
Inventor: BROWN ROLAND
IPC: B41L11/00
Filed: 1953-04-23
Abstract: 733,262. Rotary duplicators; feeding sheets. BLOCK & ANDERSON, Ltd. Sept. 15, 1953 [April 23, 1953], No. 11269/53. Classes 100 (1) and 100 (2). In a rotary hectographic copying machine of the kind having a printing drum and a cooperating counter-pressure roller and a pad for damping directly the copy sheets, automatic sheet-feeding mechanism is provided which comprises a rotary feeding couple positioned next before the pad in the line of feed, the couple being driven intermittently by the printing drum to feed the sheets past the pad to the drum. The sheets are fed from a tray to the rotary feeding couple by a reciprocating friction feed roller. The duplicator is of the type comprising a drum 2, Fig. 1, having a movable clip for retaining a master sheet thereon, a co-operating impression roller 3, and a damping pad 4 for moistening the copy sheets. The pad 4 is mounted in a housing 56 for pivotal movement about an axis P by means of a cam 52, secured to the drum shaft, which actuates a lever 59 freely pivoted about the axis P and biased upwardly by a spring 60. The housing 56 carries an adjusting-screw 63 which bears against the lever 59 under the action of springs so that the position and timing of the motion of the pad 4 can be adjusted. The operation of the pad 4 is such that an undamped margin is left on each sheet. Pile tables; sheet separating and feeding.-The stack of copy sheets 50 rests on a removable table or tray 10 having upstanding sides 39, and a base 41 provided with lateral guide-plates which fit into grooves in the side frames of the machine. Recesses in these plates are engaged at each side of the tray 10 by a finger 104 which can be depressed, against the action of a spring 108, when the tray is to be withdrawn from the machine. The tray 10 is slotted to receive two adjustable side guides 70 for the sheets 50, each guide having at the rear end a rubber or other friction pad 77, and at the front end a plastic or other smooth-faced block 78 (not shown). These pads and blocks, which are carried by metal clips which are clamped to the side guides 70, engage the sides of the stack of sheets 50. The sheets are separated from the stack by means of a friction roller 5, comprising a number of rubber discs, which fits over and is coupled to a one-way clutch on a shaft 6. The shaft 6 has a cranked end 7 removably secured in a carriage 8 reciprocable along a guide-rail 9 secured to the side of the tray 10, the carriage having a striker bar 12 engaged by the free end of a pushbar 19 which is reciprocated by a bell-crank lever 16 engaging a cam 15 secured to the shaft of the drum 2. The carriage 8 is moved to the right by the cam 15, but the bar 19 and the carriage return under the action of springs. The one-way clutch allows the roller 5 to rotate over the sheets on the inoperative movement to the left, but on the return stroke the roller is looked and feeds the top sheet 50 between the bight of a pair of narrow feed rollers 21, 40. The roller 21 is covered by rubber &c. and is secured to a shaft 22 to which is coupled, through a one-way clutch, a lever 33 which is slotted to receive a pin on a pivoted lever 29. The lever 29 is adapted to be oscillated by levers 27, 23 actuated by the cam 15. The non- driven roller 40 has its shaft housed in bearing lugs formed in a spring-plate 54 secured on an apron 35 which is part of the tray 10 and forms a funnel-shaped discharge end therefor. The roller 21 is stationary when the forward edge of a sheet is fed thereto, but it is then rotated through 90 degrees counterclockwise to feed the sheet between the bight of the printing couple 2, 3. The damping pad 4 is now depressed against the sheet. Since there is no positive coupling between the push-bar 19 and roller 5, the tray 10 together with the roller and its feeding mechanism can be readily removed. In a modification shown in Fig. 3, a pin 87 on the push-bar 19 is engaged by a latch lever 85 pivoted at 86 on the carriage 8 to form a releasable coupling. A trip lever 89, secured to the crank 7 on the shaft of the friction roller 5, is adapted to engage and depress the opposite end of the latch lever 85 to release the bar 19 when the roller 5 is swung into the chain line position so that if the drum 2 is rotated the bar 19 merely pushes the carriage 8 along the rail 9 and out of the feeding zone.