Patent GB-671047-A (GB)
Title: Improvements in or relating to multi-ply bag tubing machine
IPC: B31B39/00
Filed: 1949-05-26
Abstract: 671,047. Making paper bags. ST. REGIS PAPER CO. May 26, 1949 [June 18, 1948], No. 14109/49. Class 94(ii) [Also in Group VIII] In a machine for forming multi-ply stepped-end bag tubts, a series of superposed webs with their longitudinal edges in stepped relation are perforated part-way across at bag length intervals, leaving unweakened areas between the lines of perforations, and are fed through a tube former with their lines of perforations in stepped relation, after which the multi-ply tube is slit longitudinally for short distances at the ends of the lines of perforations and a cutter operates transversely across the unweakened areas so that a tensioning device is able to separate the tube into stepped-end tube portions. In the example five webs 10-14, Fig. 1a, are drawn from a sequence of five rolls (not shown) mounted in slightly staggered arrangement so that the longitudinal edges are stepped transversely on arrival at perforating and glueing units A, B, C, the webs 10, 11 being passed through unit A, webs 12 and 13 through unit B, and web 14 through unit C. Webs 10, 11 pass around guide rollers in unit A and are superposed before being fed through a perforator 35 which perforates them concurrently and identically at bag length intervals, along lines 36, 37, Fig. 28. While in the unit A they are again separated, and web 11 is passed through a glue-printing device 39 which applies a pattern of glue 40, Fig. 28. The intermediate pair of webs 12, 13 are superimposed and perforated simultaneously in the adjacent unit B, and are separated before passing through their individual glueing devices 50, 54 at which glue patterns are applied, the perforations in this pair of webs being shown at 47, 48 respectively, and the glue patterns at 51, 55, Fig. 28. The lowermost web 14 receives relatively offset lines of perforations 61 and a glue pattern 63 at unit C. Printing rollers may be provided at this last unit to apply printed matter in predetermined position relative to the lines of perforations. The separated webs are next fed around rollers 64 on a " pagoda " D provided with a longitudinal seam-glueing unit 66 at which glue lines 67, Fig. 29, (not shown), are applied along the exposed undersides of the stepped edges of the successive plies of the webs. after which they are fed into a tubing unit E, of known type, for folding the lateral edges over into the form of a tube with the glue lines 67 forming longitudinal seams. On leaving the tubing-unit the flat multi-ply tube is fed through successive rollers 71, Fig. 1b, to a slitter 72 which provides short longitudinal slits 73, 74, Fig. 30, near its opposite sides, at intervals corresponding to successive bag lengths, and a subsequent cutter 75 cuts the tube transversely at bag lengths outwardly from the longitudinal slits 73, 74. 'Concurrently with the latter cutting the tube is separated into bag lengths by tensioning-rollers 78, 79 mounted on the entry and exit side respectively of the cutter 75, the latter having a higher peripheral speed than the former. The lines of separation are shown at 76, 77, 80, in Figs. 31. The bag tubes thus formed pass on to discharge and conveyer units of conventional con veyer units of conventional construction in readiness for the bottom-forming operation. Perforating units. The perforating and glueing devices are of generally similar construction at each of the units A, B, C, the devices of unit B being shown in Figs. 3 and 7, and the relative webs designated W-1 and W-2. The perforating device comprises a stationary, transversely extending, bar 91, Fig. 7, with a serrated upper edge 92 which co-operates with the bevelled edges of three cutter-bars 94-96 adjustably mounted on a roller 93. The stationary bar 91 is adjustably mounted on a support 97 by screws 98 extending through slots in the bar. The three cutter bars 94-96 on the roller 93 conform to the curvature of the roller and sweep across the serrated edge of the stationary bar 91. Slotted lugs 102 on the central cutter bar 94 enable that bar to be adjusted relative to the others to obtain either aligned or staggered lines of perforations such as 47, or 36 and 61, Fig. 28. Rapid adjustment of the cutter bar 94, after slackening the bolts in the lugs 102, is effected by a rack and worm arrangement 104, 105, Fig. 11, the extent of adjustment being indicated by a pointer 108' on one of the lugs 102 and a scale 108 on the roller 93. The cutter bar 94 is also adjustable relative to its mounting bar 101, after loosening screws 110<SP>1</SP>, the adjustment being effected by a series of screws 112 with their ends engaging the rear edge of the bar 94. A small amount of radial adjustment of the latter is provided by set screws 113 between the inside face of the cutter and the mounting bar 101. The two cutter bars 95, 96 are adjustable in the axial direction of the roller 93. Glueing devices. Two similar glueing devices 130, 131 are employed in the unit B, Fig. 3, to apply glue to the webs W-1, W-2. Device 130 co-operates with a roller 132 beneath which web W-2 is fed to receive glue from "printing pads" 135 on a rotary applicator 134 associated with a transfer roller 140, pick-up roller 138, and glue pan 137. The glue pan is mounted with both vertical and horizontal adjustment, the latter transversely to the direction of web feed, and can also be moved sideways to facilitate removal. Rollers 141 on the underside of the pan run on grooved tracks 142 carried by a wedge-shaped support 143 which has both sides provided with rack teeth along their bottom edge to engage pinions on a rotatable shaft operated by a hand-wheel. The rollers of the glueing system are driven from a lower horizontal shaft 173 with a bevel drive 174 to a gear-box and manually operated clutch controlling a vertical shaft 176 which has bevel drives to the gear wheels of the. upper and lower glueing units 130, 131, The " pagoda" D, through which the spaced webs 10-14 are fed, is arranged to vary the extent by which the lines of perforation of the successive bag plies overlie one another, this being effected by relative adjustment of the rollers 230-234, Fig. 14, over which the-webs are passed. Since in the example the webs 10 and 11 are perforated identically, their guide rollers 234, 233 are adjusted concurrently, and the rollers 232, 231 carrying the identically perforated webs 12 and 13 are likewise adjusted concurrently, the roller 230 supporting web 14 being adjusted separately. The adjustments are effected by locating the end bearings of the roller shafts in separate guide blocks which are slidable within grooves formed in the flanged inclined faces 228 of the " pagoda," each guide block having an adjusting-screw therethrough which can be adjusted by bevel gears on an adjusting-shaft associated with, and parallel to, its particular roller. The several adjusting shafts can be rotated selectively, e.g. in pairs or individually, by a control shaft 276 carrying a plurality of splines and adjustable longitudinally so that one or more splines drive bevel gears rotatably mounted in fixed supports adjacent to bevel gears on the ends of the adjusting-shafts, Fig. 16 (not shown). Longitudinal movement of shaft 276 is effected through a hand-wheel driving a shaft 292 carrying a pinion 291 in engagement with rack-teeth 290 on the lower end of shaft 276; rotary movement is effected similarly by a hand-driven shaft 301 driving bevel wheels 300, 295, the latter being splined on shaft 276 to allow longitudinal movement of that shaft. Adjustable differential gearings are provided for varying the angular positions of the longitudinal slitters 72, Fig. 1b, and transverse cutters 75 with respect to the perforating knives while the machine is running. Shown in detail in Fig. 24, the slitters comprise a pair of arcuate knives 380 with serrated edges of a length corresponding to that required for the slits 73, 74, Fig. 30. These knives 380 can be bolted in various angular positions about hubs 380a which can also be adjusted axially of their supporting shaft in order to operate on bag tubes of various widths. Rollers 379 co-operating with the slitters and located beneath the webs are provided with circumferential grooves to receive the cutting edges. The transverse cutting device 75 which severs the webs transversely into bag lengths at 76, 77, Fig. 31, comprises a stationary cutter bar 382 mounted on a frame 383 beneath a co-operating rotary drum 384 with cutting-bars 385 adjustably mounted on it near each end. Mounted at the entry and exit sides of the rotary cutter drum 384, and at each end' of the drum, are co-operating pairs of upper and lower feed rollers 391, 389 and 392, 390, of which the upper rollers 391, 392 are mounted on the outer ends of rocking- levers 395, 396 carrying cam-engaging rollers at their inner ends. Arcuate cams 404 on each end of the drum 384 are arranged normally to hold the rocking-levers 395, 396 elevated so that the feed rollers thereon are inoperative until, the cutters 385 act on the web, whereupon the rocking levers are lowered and the rollers engage the webs at the front and rear sides of the cuts. Since the exit rollers are driven at a higher speed than the entry rollers, the tube is pulled apart along the perforated lines indicated severally at 80, Fig. 31, thereby separating the tube into bag lengths.