Patent GB-1208104-A (GB)
Title: Improvements in or relating to the cutting of sheet material
Inventor: CREFFIELD DAVID FRANK
IPC: C14B5/00
Filed: 1966-11-16
Abstract: 1,208,104. Cutting-out presses. SAMCOSTRONG Ltd. 15 Nov., 1967 [16 Nov., 1966], No. 51259/66. Heading B4B. An apparatus for cutting sheet material comprises a press 30 having a bed 38 and a beam 42 on which a knife K can be detachably clamped and a table 32 for supporting a knife, the apparatus being arranged so that, in a knife securing operation, the bed is raised to bring the knife into engagement with the beam and thereby actuate means Cc<SP>1</SP>, 62 to clamp the knife in position on the beam. The knife clamping means includes a pair of bars 62 slidably mounted brackets 52 fitted on the front and rear faces of the beam 42. The bars are provided with slots 82 which are shaped to allow projections 84, Fig. 2, on the knife K to enter the slots when the bed 38 is raised towards the beam and to lock on the projections when the bars are moved axially by means of a piston- and-cylinder device 74, 76, Cc<SP>1</SP>; the brackets 52 are fitted with pegs 58 adapted to locate in holes 60 in the knife in order to correctly align the knife. The table 32 is formed in three sections, a hardened steel plate 104, a plate 106 of synthetic plastics material and a separator plate 108 of a transparent plastics material. The three plates are secured to bars 110, Fig. 2, which are supported on spring-loaded rollers 114 fitting in grooves 112 in the bed. The front end of the bars are interconnected by a bar 122, Fig. 7, having secured to each of its ends plates 124 on which rollers 126, Fig. 8, are mounted; the rollers are arranged to run on support arms 130 secured to the bed. The stroke of the table may be adjusted by means of a cam 148 slidably mounted in a square-section tube 150 and movable by means of a screw 154. The cam is adapted to engage a roller 151 on a valve VH1 controlling the flow of fluid to a piston-andcylinder device CHl, Fig. 7, connected to the table. The tube 150 passes through a square hole in a bush 160, Figs. 7 and 8, which may be rotated by means of a manually controlled rod 168 in order to move the cam out of alignment with the valve VH1 in order to permit the table to travel the full stroke of the cylinder CHl. The material to be cut is fed from a conveyer means 34, Fig. 1, which is provided with a number of rolls R of the material so that a lay of e.g. ten layers may be fed on to the table. The leading end of the lay of material is clamped on to the table 32 by means of a bar 90, Fig. 7, connected at its ends to levers 172 pivotally mounted on the end plates 124, the levers being connected via chains 181 to a piston- and-cylinder CH2. When the table is actuated to move the section 104 thereof under the beam 42, the cylinder CH2 is also actuated so that under the action of springs 177, the bar 90 grips the material so that the latter travels with the table. After a cutting stroke, the bar 90 is released so that the table can return leaving the material in the press. At a second cutting operation, the previously cut material supported on the section 106 of the table passes over a stacking device 36, Fig. 1, and the blank is removed from the remaining material by means of a separator device including four bars 232, Fig. 1. Each bar 232 supports a number of spring-loaded elements 236 on to any of which a plate 250 may be releasably connected; the edge (250a, Fig. 16) of the plate is shaped to conform with that of the blank. When the bed rises to effect a cutting operation, the table sections 106, 108 rise and press the blank against the elements so that when the bed is again lowered the blank is progressively laid on a stack 5 of the device 36. The edge 250a, co-operates with a correspondingly shaped edge (108a, Fig. 16) of the table section 108 so that the blank is completely severed from the remaining material. The stacking device comprises a pair of arms 196 provided with rollers (202, Fig. 6) adapted to run on posts (182). A pallet P rests on the arms which are raised and lowered by a piston-and-cylinder device Cs<SP>1</SP> and a chain (194, Fig. 6). The required height of the stacking device is controlled by a pnuematic sensing device comprising blocks (208, Fig. 12) mounted on the table section 106 and each provided with an aperture (216) coupled by pipes 218, 226 to a source of air pressure. The apertures are normally open to atmosphere but when one or more is closed by contact with the upper surface of the stack, a pressure pulse is produced which, via an amplifier, actuates a valve to cause fluid to flow to the cylinder Cs<SP>1</SP> and thereby lower the stacking device. When a knife is to be loaded into the press, the knife is positioned on the table section 104 and blocks (96, Fig. 17) then fitted over the clamping bar 90, the blocks having pins (98) for engagement with holes (100) formed in the projections 84 on the knife. The table is then moved so as to position the knife under the beam; the blocks may be provided with magnets (102) in order to prevent them moving during the operation. A control circuit (Fig. 18) is provided so that the cutting apparatus can be operated either in a single-stroke mode or in a fully automatic mode.