Patent GB-702459-A (GB)
Title: Improvement in plate lockup for printing press
IPC: B41F27/10
Filed: 1950-08-08
Abstract: 702,459. Printing-surfaces. GOSS PRINTING PRESS CO. Aug. 8, 1950 [Aug. 26, 1949], No. 19745/50. Class 100 (2) A tension lock-up for a stereotype plate comprises a pair of finger bars engaging in pockets in the leading and trailing edges of a plate, the leading edge finger-bars being adjustable by cam surfaces to effect a peripheral or skewing movement of the plate to locate it in a desired position of register on the cylinder and the trailing edge finger-bars being resiliently urged to place the plate in tension, this resilient tension having to be overcome to allow of the installation or removal of the plate. In an embodiment used for a press for printing magazines, the plates 40, Fig. 7, and further plates mounted alongside without any substantial gap between the edges, are movable axially to adjust side-lay. The plates 40 have a central portion 42 with a recess 43 engaged by a projection 90 on a nut 93 threaded on a shaft 200 so that by rotation of a dial 103 attached to the end of the shaft the plates 40 may be axially moved. Further shafts 201, 202 telescopically mounted within shaft 100 and controlled by dials 104, 105 adjust adjoining plates, and a further three sets of plates may be adjusted from the other end of the cylinder. The mechanism for effecting peripheral adjustment. and skewing of the plates comprises a series of gripping fingers 71, Fig. 11, formed on a bar 70 having sloping recessed cams 110 which are engaged by cams 105a, 106a of travelling blocks 103, 104. Cams 105a, 106a have slopes in opposite directions and when they are moved closer together or further apart peripheral adjustment is effected, and when they are both moved in the same direction, skewing is effected. The former movement is caused by rotating shaft 102 by an end dial 117, Fig. 9, and maintaining a dial 115, threaded on shaft 102 still, so that block 103 free on shaft 102 between locking collars 120, 121 is moved in one direction. Block 104 is threaded to the shaft 102 with a double-pitch thread causing an opposite but equal movement to that of block 103. The shaft 102 is maintained in a rightward direction by a spring 130 in a recess 131 formed below the shaft 102. For plates 40a &c. to the right of plate 40 the respective shafts are urged to the right by coaxially assembled springs. The skewing movement is caused by rotation of a dial 115 (with dial 117 fixed) which by means of thread 116 axially but non-rotatably moves the shaft 102 and both blocks 103, 104 travel correspondingly in the same direction. A similar series of gripping fingers on a bar coacting with blocks 150, 151 having similarly directed cam surfaces 152, 153, Fig. 14, tension the plates 40 at their trailing edge, an amount determined only by the pressure of springs 160, 161 acting on the blocks 150, 151. Positive or retracting movement of the blocks 150, 151 is derived from nuts 174, 175 which move axially upon rotation of a shaft 170 from a dial fitted thereon at the end of the cylinder. Adjoining plates are tensioned by similar blocks operated from shafts telescopically mounted within the shaft 170 and also having dials at the end of the cylinder. In an embodiment for use with newspaper colour presses where reversal of cylinder rotation is required the gripper fingers on both the leading and trailing edges have peripheral and skewing adjustments fitted and used as above according to the direction of rotation of the cylinder. The adjustments in this case are made by wrenches attached to squared shafts 218, 225, 286, 286a, 299, 299a, Fig. 20, accessible from the peripheral surface of the cylinder. Shafts 218, 225 at each end adjust the side lay of the outer and inner plates respectively by a worm drive to axially disposed shafts carrying nuts with projections engaging a recess in the centre of each plate in a manner similar to the first embodiment. Squared shaft 286 may effect skewing adjustment on the leading edge of the plate by rotation of a worm-wheel 285, Fig. 23, rotating a gear 284 journalled in a fixed mounting 233 and so effecting non-rotational axial movement of a shaft 250 effecting unidirectional movement to cam-blocks 252, 272. Peripheral adjustment is effected by the squared shaft 299 carrying a worm gear 298 rotating a gear 297 slidingly carrying a key 294 to eftect rotation of shaft 250. If, e.g. shaft 250 is turned so that its threaded engagement in axially fixed gear 284 causes a leftward axial travel of the shaft 250 cam block 272 is moved correspondingly to the left against return spring 275 by a collar 274 attached to the end of shaft 250. The left-hand cam block 252 moves a corresponding distance rightwardly because nut 260 although threaded in the same direction has a doublepitch threaded engagement with the shaft 250. The opposing direction of travel effects peripheral adjustment. A similar mechanism denoted by suffix a reference numerals tensions the trailing edge of the plate an amount determined only by the strength of springs 261a, 275a, the skewing shaft 286a being set in mid position. Since these two mechanisms are similar they each can engage the leading or trailing edges of the plates 40 according to the direction of rotation of the cylinder. Reference has been directed by the Comptroller to Specification 583,771.