Patent GB-1265572-A (GB)
IPC: B65B9/093
Filed: 1969-05-07
Abstract: 1,265,572. Packaging. DOW CHEMICAL CO. 7 May, 1969 [8 May, 1968 (2)], No. 23356/69. Heading B8C. An apparatus for filling a chain of connected bag elements 10 wherein each bag element normally includes closed bottom and top ends 30, 32 and two sides 20, 22 which are closed, e.g. by vertical seams 24, except at their uppermost extent thereby forming an open-ended loop 34 at the top end of each bag element, comprises a mandrel 88 about which the loop portion 34 of the bag chain is fed, means, such as a knife 94, to part the loop 34 of each bag element in the longitudinal direction thereby forming a fill opening for each of the bag elements located between the two closed sides thereof and the two parted edges of the loop, and means, such as a hopper 116, to fill the bag elements through the respective fill opening thereof. As shown, a chain of bag elements 10 having two weakened slits 42, 44 joined by a portion 46 in each seam 24, is fed, preferably from a Z-like stocking 82, to the mandrel 88 with the loop 34 of the chain threaded on to the mandrel in curtain-and-rodlike fashion, the knife 94 slitting the loop 34 to provide two parted edges 102, 104 which are engaged by a pair of endless belts 106, 108 driven by separate pulley systems. The belts drive the edges 102, 104 around a filling hopper 116 where they are stopped for a time interval to allow a charge, or fill, to be dropped, through the hopper 116, into the respective bag, and then to a pair of sealing bars 142, 144 which are heated, for instance by electricity, and which are closed together, when the belts 106, 108 stop, to seal upper edge 16 of the bag to provide a leakproof closure of the fill opening, a trimmer 172 removing an upper edge of the sealed portion. As the bag elements 10 are released from the belts 106, 108, they are allowed to fall and, due to their own weight, break away at the weakened slits 42, 44. A lower conveyer system 160, synchronized with the movement of the belts 106, 108, supports and drives the bottoms of the bag elements, and vibrates each bag up and down while it is being filled through the hopper 116. The belts 106, 108 and conveyer belt system 160 are driven by an electric motor, not shown, which is controlled by an electric eye which focuses on a printed legend on each bag 10. In a modification, Figs. 7, 8 (not shown), endless belt systems (59, 61) move the chain of bag elements past the filling hopper (116) and, during the stop interval for filling operations, the last bag filled is pulled from the next preceding one by a second separate endless belt system (107, 109), located at the closing and sealing station. A conveyer belt (119) supports and drives the bottom ends of the filled bags which, while stationary at the filling station, are vibrated by a vertically reciprocable conveyer belt 91. The belts (107, 109) are heated by elements (103, 105). In a modification, Fig. 14 (not shown), the bag chain has top and bottom gussets, the seams (24a) terminating adjacent the leading edge (202) of the shorter leg (192) of the upper gusset to provide the threading loop, the weakening of the seams 24(a) between the bags being by thinning a strip along the centre of each seam 24(a) which is also provided with an aperture (204) at its upper end. In an alternative arrangement, generally similar to that shown in Fig. 14, triangular shaped cut outs (206, 208) are located at the upper and lower ends of each seam (24(b)), Fig. 18 (not shown), which seam extends partially along the inclined sides of each cut out. The gussets spread apart upon filling, and the weakening of the seams is by centrally located perforations. Another arrangement, generally similar to Fig. 18 (not shown), the two legs of each gusset extend approximately 180 degrees apart. In another arrangement the threading loop is thinned by forming it of a single ply while the bag elements are composed of laminated plies, or by forming it of thinner material. The threading loop may be provided with a series of longitudinally spaced cut outs which are employed to time the filling and closing operations, and the perforations along the seams may extend around the threading loops. The bag elements may incorporate valves especially when the filling is a powdered product so that excess air can escape from the bag. In another arrangement the threaded loop is formed by a separate inverted U-shaped strip which is sealed to the upper edges of separate bag elements which may have side gussets. The bag elements can be formed of paper, burlap, cotton and plastics e.g. PVC.