Patent GB-830952-A (GB)
Title: Improvements in or relating to the manufacture of tubes from corrugated paper and the like
Inventor: MOLLA PIETRO
IPC: B31F1/00
Filed: 1958-02-18
Abstract: 830,952. Tube-making machines. S.A.F.F.A.-SOC. PER AZIONI FABBRICHE FIAMMIFERI ED AFFINI. Feb. 18, 1958, No. 5311/58. Class 99(2). A machine for automatically forming tubes from sheets of single or double corrugated paper by overlapping and joining by adhesive the marginal portions of each sheet, comprises an endless conveyer 4 for feeding the sheet a through the machine, a holding and positioning device comprising rollers 33, 331, 34 and 341 for gripping the sheets and rotating at a peripheral speed equal to the speed of advance of the sheets on the conveyer, a device for flattening one edge of each sheet and consisting of profiled guides which cooperate with one another and are so shaped that one or more of the corrugations of one margin of a sheet is flattened, a device 61 for applying adhesive to the lower face of the flattened margin of each sheet, a device 70, 70<SP>1</SP> for bending the sheet and overlapping the margins such that a flattened margin overlaps an unflattened margin, a guide 65 which extends parallel to the direction of advance of the sheets and which prevents lateral displacement of the sheets when passing from the margin-flattening device to the bending device, and a second guide 76 provided in that portion of the bending device in which the margins are overlapped and arranged to ensure the exact overlapping of the margins. As shown, sheets a of corrugated paper are introduced into a hopper 1 adjustable laterally on a bed-plate 2 provided with a longitudinal groove housing the upper run of a continuous conveyer 4 comprising links 10 on which are secured interchangeable drivers 11 to feed the sheets through an aperture 12 in the base of the hopper; the conveyer chain engages toothed wheels 13, 14 on shafts 25, 29, the shaft 29 being driven, through a chain wheel 15 and chain 16, by a motor unit. The drivers 11, Figs. 4 and 5, are chamfered at 17 to ensure extraction from the hopper of the sheets one by one and without damaging the edge of the sheet above that sheet which is about to be extracted, and are secured to the links 10 by a stem 18 recessed for engagement thereof by a spring-loaded ball 20 incorporated in the links. To facilitate removal of the drivers, a lever 22 engages a cam 23 slidable on the shaft 25, and the toothed wheel 13 has mounted thereon coned members 24 associated with return springs 26 and spring-loaded plungers 27, and when the lever is rocked to displace the cam the members 24 are displaced laterally and impart vertical movement of the plungers 27. A sheet of paper withdrawn from the hopper travels between guides 5, 5<SP>1</SP> and is kept in position by a cover plate 28 adjustable in height, and passes under the roller system 30 comprising parallel shafts 31, 32 carrying the rollers 33, 331 and 34, 341, the shafts being coupled through a gears 35, 37 and a chain 36 and driven by a chain 39 coupled to the drive for the machine. The shafts are mounted in brackets 40 carried on spring-loaded hinges 41 and, by actuation of screws, the height of the rollers 33 ... 341 is adjusted to conform to the thickness of the sheets and to yary the degree of pressure exerted by the rollers on the sheets. Flattening of the edge of a sheet is effected by passage of the sheet between profiled guides 44, 45, Figs. 8 and 8a which separate the corrugations to be flattened and, in conjunction with a guide 46, folds over the marginal half-corrugation. A pair of electrically-heated rollers 47 with peripheral indentations 59 straightens the edge by impressing knurling thereon. The blade-like guide extends to the roller 33 and enters into the channel preselected for separation of the corrugations to be flattened. The guides 44, 45 and 46 are secured to the bracket carrying the rollers 47 and together with the latter are displaceable transversely of the machine. After flattening, the edge of the sheet receives a layer of liquid adhesive from a rotatable disc 61 operating within a container 60 displaceable laterally according to the width of the sheets. During the knurling of the edge of a sheet and until the sheet is formed into a tube the guide 65, which has a suitably profiled lower edge, engages between two corrugations of the sheet, the guide being provided with an extension for adjustment of the height thereof relative to an interchangeable metal core 69 heated by internal, electrical resistances. Gradual folding of the side edges of a sheet is effected by relatively-adjustable helical guides 70, 70<SP>1</SP> and round bars 71, 71<SP>1</SP> pivotally mounted and facilitating folding of the sheet around the core 69 under which the sheet passes. Exact superimposition of the edges of the sheet is controlled by a guide comprising a bearer plate 75, adjustably arranged on the guide 70<SP>1</SP>, and the vertically and laterally adjustable guide bar 76 against which rests, slidably, the corrugation which delimits the flattened edge of the sheet. The formed tubes with the edges thereof superimposed are received under a pressure bar 81 and between laterally-adjustable guides 82, 82<SP>1</SP> with divergent entry portions 85, 85<SP>1</SP> and disposed one on each side of the core 69. The guides are arranged to be slightly convergent towards the exit end thereof to obtain a gradual compression of the corrugations. The bar 81 houses electrical resistances which together with those in the core produce the heat necessary for setting the adhesive. A block 91 carrying the bar 81 is supported on at least two lifting screws 93, 931 supported by brackets 95 and rotated simultaneously in nuts 94 by a shaft 98 and intermediate worm and wheel gearing. To facilitate advancement of the tubes against the friction set up between the tubes and the bar 81, a continuous steel band 100 mounted on pulleys 101 rotates around the bar 81 and block 91, the band moving in the same direction and at the same speed of advance of the tube. The pulley which drives the band is keyed on a shaft 102<SP>1</SP> chain-driven from the shaft 29; one pulley is spring-loaded to tension the band. The finished tubes are ejected from the machine by a roller 114 having a knurled surface and a peripheral speed greater than the translational speed of the tubes so that the tubes are advanced rapidly away from the drivers 11 before the latter descend below the bed-plate 2 and so prevent chafing by the drivers of the edge of the tubes. The roller is driven from the shaft 29 by a chain 117 and a tube-counter is arranged in front of or behind the roller. Specifications 704,186, 734,334 and 759,087 are referred to.