Patent GB-570483-A (GB)
Title: Improvements in registering and trimming of printing plates
IPC: B41D5/00
Filed: 1944-03-11
Abstract: 570,483. Trimming stereotype plates. WOOD NEWSPAPER MACHINERY CORPORATION. March 11, 1944, No. 4568. Convention date, Nov. 4, 1943. [Class 100 (ii)] A machine for trimming the edges of curved stereotype plates is provided with adjustable pointers whereby each of a set of plates for multicolour printing may be adjusted in the machine so that the trimmed edges are in the same position relatively to register marks on the plates. The plate 27, Figs. 4 and 6, to be trimmed is placed upon a saddle portion 28, Figs. 3, 4 and 6, of a rotatable cylinder 17 with one straight edge in engagement with a bar 29 on the cylinder and the plate is clamped by a pair of felt-lined straps 30 pivoted at one end to plates 32 adjustably secured to the cylinder and connected at their other ends to crank-arms 34 on a shaft 35 geared to a shaft 43 which, in the starting position of the cylinder, is coaxial with a shaft 40 mounted in the machine frame and provided with a handle 39. In this position, a pin 42 on a crank 41 fixed to the shaft 40 lies between lugs 47 on a crank-arm 46 fixed to the shaft 43. In the full-line position of the handle 39, Fig. 6, and the broken-line position of the crank 41 and pin 42, the plate 27 is unclamped and rotation of the cylinder is prevented by the lugs 47. By turning the handle to the brokenline position, the straps 30 are operated to clamp the plate and the lugs 47 are free to pass clear of the pin 42 to allow rotation of the cylinder. Unlocking of the plate cannot take place until the lugs embrace the pin 42. The cylinder 17 is secured to but capable of being circumferentially adjustable upon a carrier 18, the end hubs 52, 50 of which are journalled in the end frames of the machine. This adjustment is effected by turning a hand wheel 53 fixed to a shaft 54 geared to a screwed shaft 56 working in a nut member 57 guided in a radial slot in the carrier and having a pin 58 engaging an inclined slot 59, Figs. 4 and 6, in a member 60 secured to the end of the cylinder. The member 60 is angularly adjustable to vary the inclination of the slot. Axial adjustment of the cylinder and carrier as a unit may be effected by turning a hand wheel 70 secured to a screwed sleeve 64 which is prevented from moving axially and engages a non-rotatable sleeve nut 65. Collars on the ends of the nut transmit its axial movements to the carrier 18 and thus to the cylinder 17. The curved ends of the plate are trimmed by cutters 72 on a shaft 73 driven by a pulley 73 and belts 90 from a motor 16. A cutter 77, Figs. 3 and 6, for trimming the straight-edge 112 of the plate is secured to a shaft 78 connected by bevel gear 83 to a bevel gear 84 splined to an axial shaft 85 driven by a pulley 91 and the belts 90. The shaft 78 and gears 83, 84 are mounted in a block 80 traversed along a guide in the carrier 18 by a coarse-thread screw 82 having a pinion 92 engaging an internal gear 93 secured to a gear 95 keyed to the hub 52 and engaging a pinion 105 on a shaft 104 provided with a hand crank 103, by operation of which the carrier and cylinder are rotated and at the same time the cutter 77 is traversed along the cylinder. In the starting position of the cylinder a pin 97 on a crank-arm 100 engages a radial portion of a circular groove 99 in the end of the gear 95 to lock the cylinder against rotation, the pin being movable into the circular part of the groove 99, to permit rotation, by turning a hand crank 102 on a shaft 101 to which the arm 100 is secured. Two spaced-apart pointers 19, Fig. 6, are adjustably mounted on the frame at each side of the cylinder. When the first plate of a set of colour plates is mounted in the machine, the pointers are adjusted until they register with marks formed on the plates during casting or with parts of the design which are common to all the plates. In mounting the second and subsequent plates the marks on the plates are caused to register with the pointers by adjustment, if necessary, of the cylinder circumferentially and axially by operation of the hand wheels 53 and 70. The cylinder carrier is mounted on an axis inclined downwardly towards the end where the handles 39, 102, 103 lie so that the operator can readily manipulate the machine and observe the pointers and the surface of the plates.