Patent GB-659182-A (GB)
Title: Improvements in registering and trimming of printing plates
IPC: B41D5/00
Filed: 1949-02-10
Abstract: 659,182. Printing-surfaces. WOOD NEWSPAPER MACHINERY CORPORATION. Feb. 10, 1949, No. 3728. Convention date, April 27, 1948. [Class 100 (ii)] A curved stereotype plate registering and trimming machine comprises means for securing a plate to a support located in a compartment to which is fixed a plurality of projector units, each including a light source and means for projecting an image of an index mark on to a plate on the support, means for moving the support relative to the compartment, means for adjustably moving each projector unit longitudinally and circumferentially of the plate, and means in the compartment for trimming the plate. In a machine of the general construction described in Specification 570,483, wherein a stereotype printing plate 27, Figs. 2 and 3, is clamped by straps 30 to a cylinder 17 mounted on a carrier 18, and cutters are provided to trim both curved edges and one straight edge of the plate, a pivoted cover 71 with a counterweight is provided to close the mechanism compartment 12 during trimming, so as to avoid the throwing out of chips. Four projector units U are provided, each comprising a lamp housing 51 and a projection tube 52, whereby the image of a cross hair etched on a lens in the tube is projected on to the plate near each corner thereof. Each unit U is clamped by a yoke 54 and screw 55 to a bracket B slidable on an arcuate rack segment 123 including a rack 67 engaging a pinion 68 rotatable by a knob 50, whereby the unit is adjustable circumferentially of the cylinder, being retained frictionally against gravity by a spring-pressed gib and clamped in desired position by a knob 66. Each segment 123 is fixed to slide 117 movable in a direction axially of the plate in a guide 115 or 116, being adjustable by a screw 118 actuated by a knob 19, and clamped in position by a screw 122. A scale 20 on the guide 115 or 116 co-operates with an index mark 21 on the slide 117. A stop 96, Figs. 2 and 8, for one curved edge of the plate is mounted on a slide 80 slidable in a recess in a bracket 86 mounted on a stationary gear 93. A block 78 fixed to the bracket 86 by a screw 79 and pin 89 engages in a central longitudinal slot 81 in the slide 80, and a spring 90 urges the slide to the right, a roller 98 rotatably supported on the slide 80 being thereby held against a cam 100 on the inner face of a gear 95. In operation, a plate 27 serving as the key plate of the several plates making up a set for colour printing is secured to the cylinder 17 with one side edge in contact with a stop bar 29 and one end edge against the stop 96. One unit U is longitudinally adjusted by its knob 19 to a predetermined position indicated by the scale 20, and the carrier 18 and cylinder 17 are longitudinally adjusted by a hand wheel 70 until one of the register marks 36 on the plate is in approximate alignment with the projected image from the pre-set unit U. The four units U are then adjusted longitudinally and circumferentially by the knobs 19 and 50 until the images are in exact registry with the register marks adjacent the four corners of the plate, and locked in position by screws 122 and knobs 66. The carrier 18 and cylinder are then released for rotation by a handle 102 which unlocks the gear 95, whereupon the carrier and cylinder are rotated through the gear 95 by a crank 103 almost through a revolution. As soon as the gear 95 starts to rotate, the cam 100 moves away from the roller 98 and the stop 96 moves clear of the plate edge. The trimming cutters are rotated by a motor, the cutter 77 for trimming the side edge being mounted on the carrier 18 and at the same time following the edge round and being moved axially of the cylinder by means of a screw 82 driven by the stationary gear 93. The cylinder is then returned to the starting position by the crank 103 and locked by the handle 102, the cover 71 opened, the plate removed, and one of the other plates secured to the cylinder. The cylinder is now adjusted longitudinally with the carrier 18 by the hand wheel 70 and circumferentially relative to the carrier 18 by a hand wheel 53 until the register marks on the plate are in exact registry with the images projected from the units U. The plate is trimmed as before and removed, and this procedure is repeated with each plate of the set.