Patent GB-722710-A (GB)
Title: Improvements in or relating to printing machines
Inventor: MILLINGTON ARTHUR RICHARD
IPC: B41F33/14
Filed: 1951-08-03
Abstract: 722,710. Printing-machines; feeding sheets. PRINTERS DEVELOPMENTS, Ltd. July 30, 1952 [Aug. 3, 1951; Feb. 1, 1952], Nos. 18373/51 and 2682/52. Classes 100 (1) and 100 (2). Faulty sheet feed control devices; tripping arrangements.-In a printing-machine having an impression cylinder and an optionally actuable self-restoring check action for temporarily preventing movement of the impression cylinder into printing position, a control apparatus is provided having at least one contactoperated electrical detector adapted to be operated by an edge of a sheet being fed over a feed board to the cylinder when such sheet is in register, and means responsive to the detector for actuating temporarily the check action when the edge of the sheet is not in register so that such sheet will not be printed, but subsequent sheets in register will be printed. As shown, the invention is applied to a cylinder machine of the tworevolution type, the shaft 34 of the impression cylinder 35 being mounted in bearings 33 which are vertically slidable in slotted supports 32. Sheets are fed manually or automatically over a feed board 38 to the cylinder 35 which, after printing, deposits them on to a table 40 from where delivery means 39 convey them to a pile. Each sheet is registered automatically by known means 66 on the feed board 38, and when in register the side edge engages and closes an electric contact 54 adjustably positioned on a perforated strip on the board 38, and the front edge engages and closes two or more electric contacts 55 which are adjustably arranged on a transverse rod supported in the frame 32. The side contact 54 can be removed and placed on the opposite side of the board 38, or a second contact may be provided where the sheets are to be registered at their opposite sides. Each contact 54 or 55 may comprise means to guide the sheet towards a stop plate having an aperture therein to allow the free end of a verticallysuspended contact arm to protrude slightly beyond, so that a registered sheet moves the arm to close an electric circuit which not only includes a lamp on a panel 170, but functions to complete the driving motor circuit and allows normal tripping of the impression cylinder 35. Further electric contacts 59a, 59b are arranged on a transverse rod 115, and each comprises a contact arm disposed just above the delivery table whereby a crumpled printed sheet delivered by the cylinder 35 over the table will move the arm and so close an electric circuit to energize a solenoid 60; this causes the solenoid to move a rod 50 to release a catch lever 51 and allow a pivoted lever 52 to descend and depress two foot pedals 45, 48 connected, respectively, to levers 44, 47. secured to shafts 43, 46, respectively. Rotation of the shaft 46 operates a brake 142 on a flywheel 137 secured to a drive shaft 136, and the lever 47 also operates a switch 49 to stop the driving motor 10; The solenoid 60 could also be energized by the non-operation of the side and front registration contacts 54, 55, i.e. when a sheet is not registered on the feed board 38. The shaft 136 is driven by the motor 10 through a belt and pulleys, and drives the shaft 144 of the bed (not shown) and the shaft 34 of the impression cylinder 35 through gearing 138, 143, 145; it also drives a camshaft 41 through gearing 139, 148, 149, 150 at half the speed of the impression cylinder shaft 34. A cam 58 on the shaft 41 operates a switch 57 just prior to the taking of a sheet from the feed board by the cylinder 35 to render the side and front lay contacts 54, 55 operative. The bearings 33 for the cylinder shaft 34 are slidable in the slotted frame 32, the lower bearing resting on compression springs which surround the upper ends of freely slidable rods 154, 155 arranged between an abutment plate 156, resting on a cam 157 secured to a shaft 42, and the lower bearing 33. A cam follower 159 is freely mounted on the shaft 42, and engages a cam groove in the face of the gear 150. A pin 161 on the follower 159 has pivoted thereon a latch 162 engageable with a tooth 164 on a disc 165 secured to the shaft 42. A pin 166 on the latch 162 has its free end slidable in a grooved guide 167 secured to the shaft 43. In operation, the gear 150 causes the follower 159 to swing about the shaft 42 and the latch 162 rotates the shaft 42 through the disc 165, whereby the cam 157 allows the rods 154, 155 and, therefore, the cylinder 35 to descend for printing. If, however, the control shaft 43 is caused to rotate in a clockwise direction, such as by depression of the pedal 45, the guide 167 is rotated and therefore the latch 162 is moved away from the disc 165 so that the shaft 42 cannot be rotated. This means that the impression remains tripped and a sheet passing through the machine is not printed. The pedal 45 is automatically depressed when a solenoid 56 is energized due to mis-register of a sheet, i.e. when one of the contacts 54, 55 is not closed ; or it is depressed manually, or due to the passage of a crumpled sheet under the calliper contacts 59a, 59b as described above. A pilot light 172 indicates the depression of the pedal 45.