Patent GB-1011727-A (GB)
Title: Method and apparatus for welding the wrapper for packages
IPC: B65B51/22
Filed: 1961-12-22
Abstract: 1,011,727. Packaging - machines. K. KORBER. Dec. 21, 1962 [Dec. 22, 1961; Dec. 12, 1962], Nos. 45982/61 and 46901/62. Heading B8C. [Also in Division B5] In a machine, Fig. 1, for applying and sealing wrappers 6 around packages 25, the packages 25 stored in a magazine 4 are fed singly by reciprocating drive members 3 along a feed track 2 to pass between suction wheels 5 and to press against a wrapper 6 held thereby. On further movement of the package 25 the wrapper 6 is folded to U-form therearound and the leading tucks on the narrow ends of the wrapper 6 are folded down by stationary folders 7. The package passes on a support 16 to the base of a passage 8. On upward movement of a reciprocating feeder 10a, folder 11 folds the lower flap of the wrapper upward to form the lower flap 26, Fig. 3, or 126, Fig. 2, and the package 25 passes into the passage 8, thereby folding down the upper projecting flap to overlie the flap 26. The seam is sealed (see Division B5) by hot air supplied to a pipe 24, Fig. 3, emitted through nozzles 22, 23 and directed by slots 20, 21 on to the seam. The portion of the wrapper 6 adjoining the seam is kept cool by the housing 9. The packages 25 are fed intermittently at a rapid speed so that they are not heated in passing from one position to the next. After leaving the passage 8 a plunger 14 feeds the package 25 to the base of a second passage 12. Projecting parts 15 on the plunger 14 fold in the other narrow end tucks. After return of the plunger 14 upward movement of a plunger 17 causes end flaps to be folded by members 18 thereon and the walls of the passage 12. The seams are sealed as before. In a modification of the sealing device, Fig. 2, bars 122, 123 connected by a block 124 and heated by a rod 127 effect the sealing, the parts of the wrapper adjoining the seam 126 being kept cool by the housing 109. The sealing surfaces of the bars 122, 123 are coated with a non-adherent material, such as polytetrafluoroethylene. In further modifications (not shown), a reciprocable heater bar is provided, Fig. 5, or a valve to cut off the supply of hot air to a single nozzle during movement of the packages is provided, Fig. 7. Ducts for cooling air or water may be provided in the housing. In another modification, Fig. 8, hot air is supplied through a pipe 639, passes through a slot 640 in a rotating drum 637 and is directed on to the seam by a slot 620. During movement of the packages a member 638 closes the slot 620. In a further modification, Fig. 9, the seam 726 comprises a flap 750 having perforations 751 and overlapping a flap 755. Sealing is effected by a heated bar 722 having apertures 752 therein which coincide with the perforations 751. The apertures 752 open into a suction duct 753 so that during the sealing operation the flap 755 is sucked against the flap 750. cooling and pressure may be obtained by any of the means described above. In another modification, Fig. 10, air is admitted through a nozzle 857 between the package 825 and the wrapper to provide counter pressure for the heater bar 822. In a still further modification, Fig. 11, a layer 960 of a material having a high dielectric loss factor is inserted between the overlapping parts 963, 964 of the wrapper. The layer 960 is heated by radiation 961 from high-frequency electrodes on a member 962 and becomes bonded to the parts 963, 964.