Patent Publication Number: US-6904947-B1

Title: Apparatus for wrapping articles, particularly groups of cigarettes

Description:
This invention relates to a wrapping apparatus and method, particularly but not exclusively for wrapping articles including or containing groups of rod-like articles of the tobacco industry such as cigarettes or cigarette filter rods. 
   Cigarette packs, particularly those comprising a hinged lid pack, are commonly wrapped in heat sealable transparent plastics wrapper material, which assists in protecting the packet and maintaining freshness of its contents. So-called soft packs have a wrapper material, often including a metal layer or a metalised plastics laminate, which is sealed around a group of cigarettes. WO98/22367 and WO98/22368 disclose a cigarette pack in which wrapper material comprising a sealed barrier layer, which may comprise a metalised plastics laminate, is formed around a group of cigarettes partly surrounded by an inner frame. The present invention is particularly but not exclusively useful in connection with wrapping articles including or containing groups of cigarettes in the production of packs in any of these styles. 
   According to one aspect of the invention, apparatus for wrapping articles, particularly articles consisting of or containing groups of rod-like articles, comprises a rotary conveyor provided with a series of locations each of which is arranged to receive at a first rotational position of the conveyor an article and a wrapper at least partly surrounding the article and having at least one overlapped region, and heat sealing means carried with the conveyor and arranged to heat seal said overlapped region before discharge of the article and wrapper at a second rotational position of the conveyor. 
   According to another aspect of the invention, a method of wrapping articles, particularly articles consisting of or containing groups of rod-like articles, comprises the steps of conveying an article and a wrapper at least partly surrounding the article on a rotary path, and forming at least one heat seal at an overlapped region of the wrapper on said path. In a preferred arrangement, wherein said overlapped region includes spaced regions for forming side seals, the method includes the step of forming side seals on substantially opposite sides of said article substantially simultaneously on said path. At least one end seal may be formed on said path, and the method may include the step of folding an end flap into an overlapped position on said path prior to forming said at least one end seal. 
   As mentioned, the apparatus and method of the invention may be used in the wrapping of cigarette groups in wrapper material, eg to wrap cigarette packs, or in the production of soft packs or packs of the type disclosed in said WO97/42097 or WO97/42098. However, it will be appreciated that the invention is applicable to wrapping other articles, particularly those articles each having generally the shape of a right parallelepiped, irrespective of its constituents or contents. 
   Although it is preferred that the material of the wrapper is itself heat-sealable, the invention is applicable also to materials to which an adhesive which can be set or dried by heat has been applied at appropriate places in relation to the overlapped region to be sealed. 

   
     The invention will be further described, by way of example only, with reference to the accompanying diagrammatic drawings, in which: 
       FIG. 1  is a perspective schematic view of a cigarette packing machine, 
       FIG. 2  is a view showing product feed through the machine of FIG.  1 . 
       FIG. 3  is an end view of a sealing drum of the machine of  FIG. 1 , 
       FIG. 4  is an enlarged view of a detail of the sealing drum shown in  FIG. 3 , 
       FIG. 5  is a view in the direction of arrow V in  FIG. 4 , 
       FIG. 6  is an end view of an alternative sealing drum usable in a machine similar to that of  FIG. 1 , 
       FIG. 7  is a view in the direction of arrow VII in  FIG. 6 , and 
       FIG. 8  is a sectional view on the line VIII—VIII in FIG.  6 . 
   

   Referring to  FIGS. 1 and 2 , a machine for producing hinged lid packets containing wrapped cigarette groups, which may be in the form of resealable inner packs such as disclosed in said WO98/22367 or WO98/22368, includes a cigarette hopper  10 , which delivers cigarettes downwards to a group forming region or regions in which, groups  12  of cigarettes are formed and subsequently plunged into individual pockets of a collation conveyor belt  14 . The groups  12  are received in each pocket on an inner frame  16  delivered to the belt  14  at a position upstream of the hopper  10  and cut from an inner frame reel  18 . Presence and condition of cigarettes in each group  12  are checked by ends detectors  20  alongside the belt  14 . 
   Each cigarette group  12 , together with its folded inner frame  16 , is pushed from the pocket on belt  14  along a linear conveyor path  22  on which it intercepts a wrapper section  24  at a plunge position  26 , such that the cigarette group  12  and inner frame  16  become partially enveloped in the wrapper section (ie the wrapper section forms a U around its leading end). 
   Each wrapper section  24  is a composite panel comprising an inner foil section, delivered from a reel  28 , and an outer label section, delivered from a reel  30 . The foil and label webs are delivered in overlying relationship to a cutting unit  32 , which severs leading ends of the webs to form successive composite wrapper sections  24 . Alternatively each wrapper section  24  may be obtained from a single reel, consisting of a foil web having pre-applied labels. As a further option, the wrapper sections  24  may be foil sections obtained from a single reel, each section being defined by perforations or pre-formed score lines across the web of the reel. 
   Downstream of the plunge position  26 , wrapping and folding of the wrapper section  24  around the group  12  and inner frame  16  is partially completed in conventional manner, eg using plough and tuck folders as used on hinged lid packing machines manufactured by the applicants, to form a partially-completed pack  34 . The form of the pack  34  is shown in FIG.  5 . Tack heater bands  36  may be provided to temporarily hold the side flaps in place before the pack  34  is delivered to a pocketed sealing drum  38  at which heat sealing of the overlapped edges of the wrapper section  24  is completed. The material of each wrapper section  24  is heat-sealable. As an alternative, where the material is not heat-sealable, adhesive could be applied upstream of the bands  36 . 
   After heat sealing has been completed in the sealing drum  38 , the pack  34  is delivered to a blank folding turret  40 , at which it is received in a pocket  42  in which a hinged lid blank  44  has already been received from a blank feed and gumming unit  46 . The blank  44  is folded and sealed around the pack  34  in the turret  40 . Delivery of completed packets  48  is by way of a linear conveyor  50  to a drying drum  52  at which the adhesive of the folded blank  44  is cured and/or dried so that finished packets may be delivered along an exit conveyor line  54 . 
   It will be understood that movement of each of the pocketed conveyors  14 ,  38 ,  40 , and  52  is generally intermittent and in steps corresponding to the pitch between adjacent respective pockets, so that at least transfer to or from the respective conveyor normally occurs while the conveyor is stationary, although in principle the machine may operate continuously. 
   The machine may readily be adapted to produce packs  34 , ie without an outer hinged lid packet, by omission of the turret  40 . 
     FIGS. 3-5  show more details of the sealing drum  38 . This comprises a central hub  60  from which extend in a generally radial direction a series of profiled projections  62  (only three of which are shown in  FIG. 3 ) which at least partially define between them the pockets  64  in which the packs  34  are held. Rotatable about the same axis as the hub  60  is an inner ring  66  carrying a series of circumferentially-spaced inner heater elements  68 , and also an outer ring  70  carrying a series of circumferentially-spaced outer heater elements  72 . In normal operation the hub  60  and rings  66  and  70  rotate intermittently together, with the heater elements  68  and  72  aligned with the pockets  64  so as to provide heat to seal the side seams of the packs  34 . This is the position shown in FIG.  3 . Note that the side faces of the projections  62  are not radial but are inclined at relatively small angles to a radial direction, so that packs  34  held in the pockets  64  are correspondingly inclined, as are the operating faces of the heater elements  68  and  72 . When the machine is stopped, eg because of a malfunction, the inner and outer rings  66 ,  70  can be rotated relative to the central hub  60  by an amount sufficient to withdraw the respective heater elements  68 ,  72  from the faces of the packs  34  held in the pockets  64 : this avoids overheating by prolonged contact between the packs and the heater elements. This displacement of the heater elements  68 ,  72  by relative rotation, which as shown in  FIG. 3  consists of anti-clockwise movement of the inner ring  66  and clockwise rotation of the outer ring  70 , is facilitated by the inclined orientation of the pockets  64  and corresponding faces of the heater elements. 
   The heater elements  68  and  72  complete side sealing of the longitudinal seams of the packs  34 . End sealing, which is required only at the trailing end of each pack  34 , is also carried out on the drum  38 . 
   Associated with each pocket  64  and carried by the central hub  60  is a series of pivoted levers  74  (only one of which is shown in  FIG. 3 ) each carrying at its outer end a heater element  76  and at its inner end a cam lever and roller  78  which is engaged in a stationary cam track  80 . As best seen in  FIGS. 4 and 5 , the heater element  76  is aligned with the end of the pack  34  and is movable under operation of the cam roller  78  and cam track  80  from its position shown in the drawings to the position indicated at  76 A in  FIG. 5  at which an end flap  34 A of the pack  34  is held and sealed against the main body of the pack. Note that the movement of the element  76  into its sealing position performs the operation of folding the end flap  34 A. The heater element  76  is maintained in position against the pack for sufficient time to effect the seal, the cam track  80  being arranged so that subsequently the lever  74  is returned to the position shown in  FIGS. 3 and 4  at least prior to the respective pockets  64  receiving a new pack  34 . Means (not shown) may be provided for returning the lever  74  to its inoperative position (ie with the heater element  76  out of contact with the pack  34 ) if the machine stops for an extended period (so as to prevent overheating). 
   The orientation of the pack  34  in the pockets  64  corresponds with the orientation of the drum  38  as shown in  FIGS. 1 and 2 .  FIGS. 6-8  illustrate an alternative drum  138  in which the axis of the drum is disposed at right angles to that of the drum  38  (ie the drum  138  is orientated in a plane parallel to that of the drum  52 ). In the drum  138  pockets  164  are defined- and carried by a central drum assembly  160 . Heater elements  168 ,  172 , which engage with respective side seams of the packs  34  in the pockets  164 , are carried by respective discs  167 ,  171  which are coaxial and rotatable with the hub assembly  160  and disposed adjacent the opposite end faces of the assembly. The discs  167 ,  171  can be rotated relative to the assembly  160  to displace the heater elements  168 ,  172  from the side seams of the packs  34  in the event that the machine stops for an extended period. In the drum  138  the pockets  164  may be so arranged that the respective packs  34  are disposed so that their side faces are slightly inclined to a plane which is perpendicular to the axis of the drum. The operative faces of the heater elements  168 ,  172  may be correspondingly inclined. In this way, on rotation of the discs  167 ,  171  to displace the heater elements  168 ,  172  from the side seams of the packs  34 , separation may be achieved without rubbing or sliding movement of the heater elements across the respective side face. 
   End sealing of the pack  34  in the drum  138  may be carried out by a cam-operated pivoted lever  174  carrying a heater/folder element  176 , as indicated schematically in  FIG. 6 , which cooperates with a cam track  180  in an analogous manner to operation of the lever  74  and element  76 ; note that the heater/folder element  176  is disposed in a circumferential plane to correspond with the orientation of the packs  34  in the pockets  164 .