Patent GB-402477-A (GB)
Title: Improvements in or relating to printing machines
IPC: B41F3/44
Filed: 1932-06-07
Abstract: 402,477. Printing-machines. AVORY, A. E., 46, Marylands Road, Maida Hill, and STRAINE, H. B. K., 40, Church Lane, Hornsey, both in London. June 7, 1932, No. 16064. [Classes 100 (i) and 100 (ii).] Cylinder-machines ; feeding webs ; set-off, preventing.-A printing-machine of the reciprocating flat-bed and stop-cylinder type is provided with means for feeding thereto a continuous web to be printed, means for winding up the printed web and means for holding the web against movement or for withdrawing it at appropriate times in order partly or wholly to reduce the spaces which would normally occur between the impressions due to the gap in the cylinder and the difference between the length of the printing plate on the bed and the circumference of the cylinder. A set-off web may be fed through the machine with the web to be printed. As shown applied to a Wharf edale machine, a frame 2 adapted to be secured to the main frame 1 of the machine carries supply rolls 14, 16 for the web to be printed and a set-off web respectively, and a rewinding reel 8 for the webs which is adapted to be driven by a belt 6 from the impression cylinder 7. The shafts 13, 15 of the rolls 14, 16 are mounted in blocks 11, 10 rigidly connected together by a rod 17 and slidably mounted in a guide 9 in which is also slidably mounted a block 12 connected by a pin-and-slot connection 23 to a rod 22 rigidly secured to the block 11. Two bars 18 between which the webs pass are mounted by eccentric pivots 19 in the block 12 and are provided with arms 20 connected by links 21 to the rod 22. The block 11 is connected by links 25, 24 to a shaft 26 on which is fixed an arm 28 connected through linkage 29, 30, 32 to an arm 33 carrying a roller 35 engaging a cam 36 which may be the cam for normally operating the delivery flyer of the machine. During the printing stroke of the bed, the cam 36 acts to move the blocks 10, 11, 12 to the left, the initial movement, owing to the pin-and-slot connection 23, causing the bars 18 to rock to release the webs, and during the return stroke of the bed, while the gap 41a in the cylinder 7 is opposed thereto, the bars 18 are first turned to grip the webs and then moved to the right drawing back the web to an extent which may be determined by adjusting the point of attachment of the link 29 to the arm 28 by means of the screw 27. During this movement, the tension of the belt 6 may be reduced by the lifting of a roller 43 by a lever 41 and a rod 44 actuated by a cam or crank. The cam 36 may be provided with a step 40 and a similar step at its point of minimum radius so that the initial movements of the rod 22 are abrupt to ensure the certain opening and closing movements of the gripper bars 18. The initial relative movement of the rod 22 and block 12 is also ensured by the provision of a liner 45 for the guide 9 adjustable by set-screws to frictionally grip the block 12. The bars 18 are preferably formed with gripping parts of greater diameter than the intervening parts, the larger parts being provided with rubber bands. Additional gripping bars of similar construction may be provided between the cylinder 7 and the take-up reel 8. The shafts 13, 15 and the shaft 4 of the take-up reel preferably comprise short end portions permanently mounted in their bearings and central removable portions connected to the end portions by sliding sleeves. In machines provided with manual means for rendering the cylinder inoperative while the bed continues to reciprocate, the link 30 may have a forked upper end engaging the connecting pin on the link 29, and the operation of the manual means may be caused to lift the link 29 so as to render the gripping bars 18 inoperative.