GB974660A - Machines for performing operations on sheet materials - Google Patents

Abstract

974,660. Cutting-out presses. S. M. LANGSTON CO. Feb. 15, 1961, No. 5575/61. Heading B4B. [Also in Division B6] A machine for performing cutting, creasing, printing or embossing operations on sheets of work material comprises a platen press having sheet-working elements and constituted by relatively movable platens, means for feeding a sheet of work material between the platens, first motor means for advancing one platen towards the other to bring a sheet of work material and the elements into an initial engagement, pressure means responsive to a predetermined engagement pressure between a sheet of work material and the elements, and second motor means actuated by the pressure means for generating a working pressure between the sheet and the elements to effect the operation on the sheet. As shown, a platen 13 is movable towards and away from a sheet 1 located on a fixed platen 11 by means of an hydraulic piston and cylinder unit 21 and power for the working stroke is applied to the platen 13 through four hydraulic piston and cylinder units 22 located respectively at the four corners of the platen. The downward movement of platen 13 is arrested by contacting the sheet 1, thus permitting a pump 25 to overcome the resistance of an adjustable spring-loaded sequence valve 20, Fig. 1a, to divert pump pressure to the upper end of the four units 22 through a pipe system 30. The pressure thus permitted to enter units 22 is imposed also on an adjustable spring- loaded hydraulic pressure switch 66, the setting of which limits the pressure applied to the sheet 1 and signals the reversal of platen 13. The piston-rods 268, Fig. 14, of the units 22 are each axially adjustable with respect to the platen 13 so that the platen is adjustable relatively to the units so as to be pulled to the platen 11. The sheets 1 are fed individually from the bottom of a stack 3 towards a pair of feed rollers 8 by means of a feed bar 7 and the sheet is advanced by the rollers 8 into a pair of side guides 9. The sheet is fed to a point on the platen 11 short of a vertically-movable gate 12 and the feeding actions of the rollers 8 and the bar 7 are relatively timed so that as the trailing edge of each sheet leaves the stack, the next sheet from the bottom of the stack is fed so as to bring its leading edge into abutment with the trailing edge of the first sheet and the latter sheet is then pushed by the second sheet into engagement with the gate 12. At this point rotation of the rollers 8 is interrupted. The gate 12 in conjunction with the guides 9 accurately registers the sheet with the blanking tools on the platen 13. When the operation has been completed, the platen 13 moves upwardly, the gate 12 descends to free the forward edge of the sheet, the rollers 8 again assume their feeding function and the sheet is advanced into a pair of take-away rollers 14 which discharge the sheet and waste, if any, from the machine. The feed bar 7 is reciprocated by means of an hydraulic cylinder 15 and the gate 12 is raised and lowered by means of hydraulic cylinders 17, 18. The pairs of rollers 8, 14 are rotated by means of hydraulic motors 16, 19 respectively. Liquid is supplied from a pump 24 to the hydraulic cylinders and motors under the control of solenoid-operated valves 26 to 29 while the supply of liquid from a pump 25 to the piston and cylinder unit 21 is controlled by a solenoid-operated valve 31. The stack 3 is positioned on a feed table 2 by means of adjustable front and rear stops 4, 6 respectively and by means of side guides 5. The guides 5, stops 6 and upper feed roller 8 are movable into inoperative positions by being carried by pivotally-mounted arms 182, Fig. 3, the upper ends of which are connected to the piston of an hydraulic cylinder 186. The upper feed roller 14 is mounted so as to be movable outwardly from the lower feed roller. The blanking tools 274, Fig. 14, are attached to a plate 275 which is secured to the platen 13 through the intermediary of a carrier plate 276 by means of a tapered strip 277 and a longitudinally-adjustable tapered feather 279. The cycle of operations of the machine is controlled by means of an electric circuit, Fig. 2 (not shown), which includes the solenoids of the valves 26 to 31, the switch 66, a switch 81, Fig. 1, controlled by the movements of the feed bar 7, a switch 82 comprising a finger 83 adapted to engage the lower, surface of successive sheets 1 at a point in advance of the feed rollers 8, a switch 84 comprising a finger 85 which is adapted to engage the upper surface of successive sheets as they move over the platen 11 towards the gate 12, and a switch 86, Fig. 1a, which is positioned for engagement by the platen 13 as the latter moves into its raised position. U.S.A. Specification 1,797,692 is referred to.