Patent GB-290453-A (GB)
Title: Improvements in apparatus for curving printing plates
IPC: B41D5/00
Filed: 1927-06-10
Abstract: 290,453. Halstead, A. June 10, 1927. Printers' apparatus.-A machine for curving printing-plates by means of a rolling cylinder and a flexible band exerting pressure over the surface of a printing-plate has means for anchoring one end of the flexible band adjustably to the bed of the machine, the other end of the flexible band being secured to the rolling cylinder. The machine frame 23 has flanges 48 to support a bed 28 for the printing-plate 31, electrical heating-dements 41 being secured to the underside of the bed. The rolling cylinder 21 is mounted by means of trunnions 121 in bearings 122 received in guides 123 in a carriage consisting of end frames 124 provided with inwardly extending studs 127 carrying rollers 128 moving in tracks 129 running lengthwise of the machine frame 23; the cylinder supporting frames 124 also support a cross-shaft 131 rotatable by a hand-wheel 136 and carrying pinions 134 meshing with longitudinal racks 24, which racks are also in mesh with gears 26 on the rolling cylinder. Means are provided for pressing the printing-plate against the heating- slab during the heating of the same consisting of presser feet 54 and pressure shoes 59 carried on bars 57 with adjustable bearings 65 secured on a rock-shaft 66. Other bearings 67 for the pressure bars 57 are adjustable on a rod 68 on arms 69 fixed to the rock-shaft, weights 73 on the ends of the pressure bars holding them normally in raised position. The pressure device is lowered to engage the printing-plate by means of a treadle 112 connected by a link 107 with an arm on the rock-shaft and is held in this position by pivoted latches 75 engaging a latch bar on the machine frame. The printing-plate is positioned by means of gauges 85 adjustable on arms 86 adjustably fixed on a rod 89 carried by arms 91 with bearings 92 engaging the rock-shaft 66. The rod 89 may be connected by a latch 93 with one of the pressure bars so that the gauges may be lifted with the pressure device when the heating is completed. The flexible band 51 is conected to the rolling cylinder by a bar 141 riveted to the end of the band and having a groove 142 engaging a lip 143 on the cylinder; the other end of the band is secured to a strip 146 attached by springs 157 to an anchoring bar 150 adjustable by screws 155 and hand-wheels 156. The interior of the cylinder is formed as a water chamber 165 connected by tubes 166, 167 to a water supply for cooling the plate after bending. In the operation of the machine a cylinder of diameter corresponding to the curvature required on the printing-plate is lowered into position, with its bearings 122 engaging the guides 123 in the carriage 124, the bearings being provided with lifting-eyes 175 to facilitate this, and the carriage is retracted to a position corresponding to the length of the plate by setting a stop 171 on the carriage against a pin 172 which may be placed in one of a series of holes 173. The bar 141 of the flexible band 51 is then attached to the cylinder, the printing- plate 31 laid on the band over the heating-slab 28 and pressed down thereon by the pressure device for uniform heating, after which the pressure device is raised and the flexible band and printing-plate wrapped round the cylinder by traversing the carriage 124.