Patent GB-1462838-A (GB)
Title: Method and apparatus for automatically packaging flexible flat goods
IPC: B65B9/06
Filed: 1974-09-06
Abstract: 1462838 Packaging flexible flat goods WINDMOLLER & HOLSCHER 6 Sept 1974 [19 Oct 1973] 39084/74 Heading B8C In a method of packaging flexible flat goods, such as bags, garbage sacks, or the like, a stack is formed from goods to be packaged and is introduced into an opened half-tube of film, and whilst partially pressing the included air, is welded therein by a separating weld seam which closes the open film edges and by a separating weld seam extending perpendicular thereto to form bag packages; the half-tube of film is brought into a vertical position with its open edges facing upwardly, is pulled under the horizontal stack of goods to be packaged, and is held at its upper edges; the stack is pushed from above into the vertically suspended half-tube of film under pressure exerted from above on to its transverse centre line whilst folding the stack about this centre line, the film being supported at its lower edge; the bag is advanced by at least one width of bag package during pressing out of the air and closure by the separating- weld seams; and the following web of film is advanced by the same length. As shown, a tube of plastics film 5 is withdrawn from a reel 4 and is transversely welded and severed by tongs 6, 6 to form a succession of garbage sacks each sack being fed, by a belt 7 to a first and then a second folding station comprising respectively pairs of rollers 10, 10 and 11, 11 and associated air knives 9, 12. Each double-folded bag is fed by a conveyer 3 to form a stack on a trapezoidal, depositing plate 18, Fig. 2, and is pressed down thereon by a depressor 20 controlled by a photocell and counter unit 3.1. After the bags on the stack 19 have reached the number set on the counter a pair of conveyer chains 23, with uniformly distributed, and transversely aligned, dogs 24, are advanced by an amount equal to the pitch of two pairs of dogs to deliver the stack of bags formed on the plate 18 to a stack-folding station 14. A film, in the form of a half-tube 29 and withdrawn from a reel 30, is turned and opened respectively by bars 31, 34 to extend vertically, with its open side pointing upwardly, beneath a folding blade 25 at a filling station 15, a perforating tool 32 forming tear-line perforations 33 on both sides of the half-tube folding line. When the plate 25 descends the stack 19 is pushed between a pair of spring-loaded rollers 26, 26 which, with a pair of separating plates 35, move apart against the action of springs 38.1, so that the stack 19 is folded about a transverse centre line and is compressed, as the upper edges of the half-tube, which are engaged between the plates 35 and corresponding spring-loaded backup members 41, are spread apart to receive the folded stack 19. A web 63 of tying clips for the bags is withdrawn by rolls 64 from a supply roll 62, and a cutting tool 66 severs a length 68 from the web which is fed on to the rolls 26, 26 before the blade descends, Fig. 3, so that the length 68 of bag tying clips is folded and deposited into the open half tube as the blade 25 descends. After the folded stack 19 and a length 68 of tying clips has been deposited in the folded half-tube a welding tool, comprising opposed first plates 43, 43 each of which carries an angularly-shaped welding tool 44, is closed by pressure cylinders 50, 50 to weld the two films together along the top, and perpendicular thereto, and sever the finished packaging bag, the leading seam of the next bag being simultaneously formed on the half-tube 29. Each first plate 43 carries a spring-loaded second plate 47 and one of the plates 43 has perforating needles 48, which punch air holes in the half-tube as the welding jaws close. The welding tool is displaced longitudinally, by an amount controlled by a photo-cell 54, along guide bars 60 by a motor-driven screw 53 to pay out the halftube from the roll 30 as the welding operation takes place. An abutment pin 54, adjustable for height and located between the plates 43, supports the bottom of the half-tube and limits the travel of the blade 25. The pin 54 is also offset, in the direction of travel, from the centre of the bag being formed so that, after the bag has been displaced by the welding tool to a depositing station 16 and the jaws have been opened, the package of bags falls on to a belt conveyer 17 which transfers the package to a bin, not shown, tension rolls 58, driven by a rotary field magnet, engaging the severed film edges of the half-tube and leading them to a waste bin, not shown. These film edges can be used as tying members for the packaged bags.