GB1173744A - Improvements in Methods and Apparatus for Forming Filled Bags - Google Patents

Abstract

1,173,744. Packaging-machines. A. DOLMAN. 16 Dec,, 1966 [18 Dec., 1965], No. 53759/65. Heading B8C. In a method of forming filled bags by transversely sealing a flexible tube at intervals to enclose the material, part of the tube wall is transversely slit at spaced apart intervals and the material introduced through each slit into each bag portion. The tube may be supplied in flattened form or a web may be formed into tube and slit during formation. Sealing operation, Fig. 3.-The tube 12, which may be seamless or formed from one or two webs, is transversely sealed by sealing bars 34, 35 mounted on a frame 38 which is moved inwards towards the tube 12 by a vacuum cylinder 43. The lower sealing bar 35 seals the top of a previously filled bag whilst sealing bar 34 seals the bottom of the next bag to be filled. Positioned between the sealing bars 34, 35 is a spreading device consisting of a fixed spreader arm 48 mounted on a bar 45 extending between spring biased pivoted arms 46, 47, arm 46 being engaged by a bar 58 connected to the moving frame 38. Sleeves 52 carrying spreader arms 50 are slidable on the bar 45 and connected to each other by a spring 53. The spreading device is moved inwards with the frame 38 by the springs 56, 57 until fingers 49 and 51 on the spreader arms 48 and 50 respectively are positioned in the transverse slit in the tube whereupon the fingers 51 are moved apart by cams 55, mounted on the moving frame 38, engaging cam followers 54 mounted on the sleeves 52. The bag portions are thereby freed from wrinkles when sealed by the sealing bars 34, 35. Filling and severing operations.-The tube 12 is passed between driven feed rollers 16, 17 until a transverse slit in the tube is level with an idler roller 22, just prior to which air is blown into the slit through an air pipe 23 to facilitate the entry of a funnel 24 which is cammed downwards by the action of a cam 25 mounted on the shaft 19 of the roller 16. A predetermined quantity of nuts is then introduced into the bag portion. After filling, the vacuum cylinder 43 is operated to move the frame 38 outwards, during which movement (not shown) a one revolution clutch 20 is tripped to rotate the feed roller 16 through one revolution to feed the tube a predetermined distance. The previously sealed bag is thereby moved to a position between stationary knife blades 62 and a pivoted knife blade 63 movable with the frame 38. When the frame 38 is again moved inwards, the strip containing the original transverse slit is severed by the knife blades 62, 63 to form an individual sealed package. Slitting operation.-In one arrangement, the tube is passed upwardly from a supply reel over a floating wedge 70 held in position by bearing plates 73 disposed outside the tube, to cause the tube to be flattened in a plane at right angles to its original plane. The tube is then severed across half its width by a fixed blade 77 cooperating with a pivoted blade 78, which is mounted via linkage to the moving frame 38. When the tube is reflattened into its original plane by passing it over another wedge 71 held in position by bearing plates 76, the transverse slit 79 is disposed across one face of the tube. Alternatively, a V-shaped member (86) (Fig. 4, not shown) held in position by bearing plates (88) is disposed within the tube, the opposed walls of which are caused to move apart with one wall bridging a stepped portion of the member, whereupon the slit 79 is formed by a hot wire cutter (92). In another embodiment, a web (98) (Fig. 5, not shown) is folded around a wedge (93), the overlapping longitudinal edges being heat sealed by a sealing member (95). When the tube is stationary, a transverse slit (100) is formed by a hot wire cutter (97) moving into a groove (96) in the wedge (93). The tube may alternatively be opened out by suction whilst each transverse slit is formed.