GB348165A - Improvements in machines for reducing printing plates to uniform thickness - Google Patents

Abstract

348,165. Trimming printing-plates. CLAYBOURN, L. W., 1613, Humboldt Avenue, Milwaukee, Wisconsin, U.S.A. Dec. 9, 1929, No. 37686. [Class 100 (ii).] A machine for trimming the backs of printing- plates comprises a number of cutting members and co-operating presser devices adapted to be lifted away from the cutters. The plate 85, Fig. 6, to be trimmed is supported face downward, with its edge against a stop 113, on a bed 86 formed on its underside with guides 91 engaged by inclined guides 94 on a slide 95 reciprocable in a carriage 23 on the machine. The movement of the slide is effected by rotation of a screw-threaded rod 98 from a handle 103, Fig. 5, the effect of the rotation being registered by means of marked discs geared to the rod 98. The carriage 23 is adapted to reciprocate on guides in the frame 22 of the machine and is connected to a piston-rod 29, Fig. 6, slidable in a cylinder 27, pressure-fluid being supplied thereto through ports 40, 41 according to the desired direction of movement of the bed. The valves controlling the direction of flow of fluid are moved by a handle having a spring-projected pin adapted to engage any one of a number of holes in the frame of the machine to hold the handle in the desired position. The speed of flow is controlled by valves set by a handle 51. Movement of the bed results in carrying the plate beneath a pair of rotary cutters 117, 118, and a shaving knife 119. The cutters are driven by a sprocket chain 156 from an electric motor 60. The chain passes round wheels 154, 155, on journals 147, Fig. 10, rotatably supported in a standard 161 at the side of the machine. The shafts of the cutters are formed frusto-conical in shape and are drawn into correspondingly-shaped apertures in the journals 147 by screws 151. Each cutter 117, 118 consists of a number of sections 122, keyed to the shafts, and spaced apart by collars 134. A collar 136 is mounted on the outer end of the shaft between the outer section 122 and a ball race 141, a nut 139 locking the whole together. The end of the shaft is supported in a bearing 255 detachably secured to the frame of the machine to permit removal of the cutters. Each section 122 is formed with a number of oblique cutting-edges, the edges of adjacent sections being oppositely directed to avoid end pressure on the bearings. The sections of the two cutters 117, 118 are staggered relatively to each other, those on the cutter 118 being arranged to operate on the parts of a plate left by the spaces between the sections on the cutters 117. The knife 119 is adjustably secured to the face of a block 234, Fig. 14, detachably secured to the machine frame. Sets of presser rollers 165 .. 168 are provided adjacent to the cutters for the purpose of pressing the plate into close contact with the bed 86. The rollers are supported in a bracket 162 slidable on the standard 161, and are each supported by spring-pressed forks 171 held against rotation in the bracket. The bracket is formed with recesses to accommodate the cutters and with apertures adjacent each cuttersection communicating with passages 197, 198 in a member 199 covering the bracket. The passages lead through a passage 200 in the standard 161 to a suction apparatus to remove the shavings formed, baffle-plates 217, 218 being provided in the apertures to direct the shavings thereto. The bracket 162 is normally secured in position in the machine by screws, but can slide on the standard 161 when it is desired to inspect the cutters. The bracket is adjustable to enable the pressure of the rollers to be regulated.