Pack for smoking articles

Abstract: The present invention relates to packs for smoking articles such as cigarettes and provides a hinged lid pack (10) comprising a box (12), the box comprising a body (14) and a lid (16) hinged to the body, and the pack further comprising an inner frame (18), wherein the inner frame is corrugated. The invention additionally provides a method and apparatus for corrugating the inner frame. Packs according to the invention can be made from lower basis weight material than conventional packs and are stronger than conventional packs.

Description: The present invention relates to packs for smoking articles such as cigarettes. Conventional hinged lid packs for smoking articles are made from paper card and consist of a box comprising a body and, a lid hinged to the body and an inner frame inside the body. The inner frame provides a surface which is overlain by an inner surface of the lid when the lid is in the closed position. Packs should be resistant to forces which act to distort the shape of the pack when it is in normal use, otherwise the contents of the pack may become damaged. While it is desired to reduce the amount of paper card used in packs, it is important that any reduction does not compromise the ability of the packs to protect their contents. The applicant has appreciated that this can be achieved by providing packs with corrugated inner frames. US 5,314,062 discloses (in Figure 10A) an inner frame for a hinged lid cigarette pack in which the side walls of the inner frame are corrugated in a direction parallel to its longitudinal axis. The purpose of the corrugated side walls of the inner frame is to allow constant carton sizes to be maintained for a wide variety of cigarette sizes. There is no disclosure that such corrugation can allow a reduction in the amount of paper card used without compromising the ability of the packs to protect their contents. Further, the corrugations at the rear of the side walls bend outwards. Packs incorporating such inner frames suffer from the disadvantage that the upper rear corners of the inner frame can catch on the side walls of the lid as it is closed. According to the invention there is provided a hinged lid pack for smoking articles comprising a box, the box comprising a body and a lid hinged to the body, and the pack further comprising an inner frame, wherein the inner frame is corrugated, characterised in that the corrugations on the upper rear corners of the inner frame curve inward so that they do not catch on the side walls of the lid as it is closed. In certain embodiments of the invention at least one of the body and the lid is of corrugated sheet material. According to the invention there is also provided a method and apparatus for corrugating material used in packs according to the invention. The lids of packs for smoking articles made according to the invention do not catch on the upper rear corners of the inner frame and the packs can be made from lower basis weight material than that conventionally used for packs while being similarly resistant to distorting forces. Alternatively, such packs can be made of conventional basis weight card and are stronger than conventional packs. It has also been found that packs for smoking articles made according to the invention have a particularly attractive appearance. In conventional hinged lid packs for smoking articles, a cut is made towards the front of the side walls of the inner frame in a direction substantially parallel to the longitudinal axis of the pack. These cuts extend, at each end, into the front wall of the inner frame to define a pair of closure tabs which project outwards from the front wall of the inner frame. The closure tabs have the advantage that they form an interference fit with an inner surface of the lid of the pack when it is in the closed position and help to keep the lid closed. However, the closure tabs become mis-shaped after the pack lid has been opened and closed several times and are no longer effective in maintaining the lid in the closed position. Closure tabs similar to conventional closure tabs in packs according to the invention, in which the corrugations extend transversely across the closure tabs, have been found to be stronger and thus more resistant to the effects of continual opening and closing of the pack lid than conventional closure tabs. The invention will be described by way of example with reference to the accompanying drawings in which: Figure 1 shows a cigarette pack according to a first embodiment of the invention; Figure 2 shows a cigarette pack according to a second embodiment of the invention; Figures 3 to 5 show corrugations which can be made to the body of packs for smoking articles which are not part of the invention claimed; Figure 6 shows an apparatus used to corrugate material used in packs according to the invention; Figure 7 shows an apparatus used to make inner frames used in packs according to the invention; Figure 8 shows a detailed front view of part of the apparatus shown in figure 7; Figure 9 shows a detailed perspective view of part of the apparatus shown in figure 8. The hinged lid cigarette pack 10 of Figure 1 comprises a box 12 comprising a body 14, and a lid 16 hinged to the body. The pack also includes an inner frame 18. The inner frame 18 is formed with corrugations 20 substantially transverse to the longitudinal axis of the cigarette pack 10. The cigarette pack 30 of Figure 2 comprises a box 32 comprising a body 34 and a hinged lid 36. The pack also includes an inner frame 38. The inner frame 38 is formed with corrugations 40 substantially parallel to the longitudinal axis of the cigarette pack 30. In other embodiments of the invention, the corrugations may extend only across the side walls of the inner frame. The cigarette pack 50 of Figure 3 comprises a box 52 comprising a body 54, a hinged lid 56. The pack also includes an inner frame 58. The front and side walls of the body 54 are formed with corrugations 60 substantially transverse to the longitudinal axis of the cigarette pack 50. The cigarette pack 70 of Figure 4 comprises a box 72 comprising a body 74 and a hinged lid 76. The pack also includes an inner frame 78. The front and side walls of the body 74 are formed with corrugations 80 substantially parallel to the longitudinal axis of the cigarette pack 70. The cigarette pack 90 of Figure 5 comprises a box 92 comprising a body 94 and a hinged lid 96. The pack also includes an inner frame 98. The front wall of the body 94 is formed with corrugations 100 which diverge from each other as they extend generally transversely across the front wall of the pack body. In other embodiments the corrugations may extend only across the front or rear wall of the body, or only across the side walls of the body of the pack. Also the corrugations may extend over all or a part of the lid and/or the body of the pack. Packs according to the invention in which the corrugations extend across a fold which defines a corner of the pack in a direction substantially transverse to the corner, as illustrated in Figures 1 and 3 have been found to be particularly resistant to distorting forces. In other embodiments of the invention, the corrugations may extend only across a fold which defines a corner of the pack in a direction substantially transverse to the corner. It is not intended that the corrugation patterns are limited to those in the embodiments described above. The distance between each trough or between each ridge is preferably between 0.5mm and 4mm. The height from trough to peak of each ridge is preferably between 0.1mm and 2.0mm. The troughs and ridges may follow any path, such as a straight line and can extend across the box or inner frame at any angle. At least two lines of corrugations may meet to form a chevron. The corrugations may extend over all or a part of the inner frame or the box. The cross sectional profile of the corrugations may follow any desired shape, such as a sine wave or a saw tooth profile. The troughs of the corrugations may be flattened so that the regions of the corrugated part of the pack which come into contact with the contents of the pack are substantially flat. Such types of corrugations have been found to have the advantage that the contents of the pack are not damaged if the corrugated material is pressed against them, for example when the pack is squashed. The apparatus of Figure 6 for corrugating sheet material used in packs according to the invention comprises a first 210 and second 212 right-cylindrical roller of circular cross section, having the same diameters and lengths as each other. The rollers 210 and 212 are rotatable about their longitudinal axes 214,216 (referred to as axes of rotation below). The curved surfaces 218,222 of the rollers have corrugations 220,224 substantially parallel to the axes of rotation of the rollers. The first roller 210 is disposed above the second roller 212 so that the axis of rotation 214 of the first roller is vertically above and parallel to the axis of rotation 216 of the second roller. Just sufficient space is left between the rollers 210,212 for a sheet 226 of card to pass between them. In operation, the roller 210 is rotated clockwise about its axis of rotation 214 and the roller 212 is rotated anticlockwise about its axis of rotation 216. As the rollers 210,212 rotate past each other, the troughs of the corrugations 220 on the first roller mesh with the ridges of the corrugations 224 on the second roller in the nip between the rollers. The sheet 226 of card is fed into the nip; as it passes between the rollers, the corrugations 220 of the first roller 210 contact one surface of the sheet 226 and the corrugations 224 of the second roller 212 contact the other surface of the sheet 226; the sheet 226 is thereby corrugated. It will be noted that the direction in which the sheet 226 is corrugated may be altered simply by feeding the sheet between the rollers at a different angle to that shown in figure 6. Typically, sheet material to be corrugated is stored as a reel. When material is required, it is unwound from the reel and fed into the nip between the rollers. Corrugated material is cut to the correct size as it emerges from the rollers before being fed into a packaging machine that assembles packs according to the invention. Alternatively, the sheet material may be cut to the correct size before it is fed between the rollers. This method can be used for corrugating material of the inner frame and also for corrugating any part of the pack. It has been found that the sheet material is more easily cut if the corrugations do not extend into the region of the material that is cut. When the corrugations do not extend into these regions, it will be noted that the margins of the corrugated material are not corrugated. Alternatively, if the corrugations do extend into the region of the material that is cut, it has been found that cutting is greatly facilitated if the corrugated material immediately adjacent the cut is supported on a surface which has corrugations similar to those of the material. The rollers may be of different diameter and/or length and/or shape to that described and of different diameter and/or length and/or shape to one another. The arrangement of the rollers may be different to that described. For example, the axis of rotation of the upper roller may not be vertically above the axis of rotation of the other roller, but instead at an angle. The rollers may move relative to a stationary sheet so that their axes of rotation traverse the length of the sheet. The corrugations of the curved surface of each cylindrical roller need not be exactly as those described in this embodiment. The height from trough to peak of the corrugations is preferably between 0.1mm and 2mm and the width of the corrugations is preferably between 0.5 and 4mm. The corrugations can have any profile in cross section, such as a sine wave or a saw-tooth profile. The troughs or the ridges of the corrugations may be substantially flattened. The corrugations may be in any direction relative to the rollers, such as substantially transverse to the respective axes of rotation of the rollers. The corrugations may extend over all or a part of the curved surface of the rollers. In conventional hinged lid packs, the rearmost portion of the side walls of the inner frame is angled inwards so that the upper rear corners of the inner frame do not catch on the side walls of the lid as it is closed. It will be appreciated that packs made according to the invention in which the corrugations extend across the rearmost section of the side walls of the inner frame have the advantage that no specific folding of the inner frame is required to prevent the lid catching on the inner frame as it is closed. It can be ensured that when the material of the inner frame is corrugated and subsequently cut, the corrugations are disposed over the regions of the material that will form the rearmost part of the side walls of the inner frame such that the upper rear corners of the inner frame curve inwards when the packs are assembled. To achieve this using corrugating rollers, the material is positioned relative to the corrugations on the rollers so that the material is corrugated and then, if necessary, subsequently cut. When corrugations are formed in a direction substantially parallel to the longitudinal axis of the pack using rollers comprising curved surfaces that are corrugated in a direction substantially perpendicular to the axes of rotation of the rollers, the material is positioned correctly relative to the rollers and to the cutting apparatus (when used). When the longitudinal corrugations are formed using rollers with curved surfaces that are corrugated in a direction substantially parallel to the axes of rotation of the rollers, the rotation of the rollers must be synchronised with the passage of the material when the material is pre-cut to the correct size and also with the cutting apparatus, when the material is cut to the correct size after it has been corrugated, to allow the corrugations of the inner frame to be positioned correctly. Similarly, when transverse corrugations are formed using rollers with curved surfaces that are corrugated in a direction substantially parallel to the axes of rotation of the rollers, the rotation of the rollers must be synchronised with the passage of the material, when the material is pre-cut to the correct size, and with the cutting apparatus, when the material is cut to the correct size, after it has been corrugated, to allow the corrugations of the inner frame to be positioned correctly. When transverse corrugations are formed using rollers with curved surfaces that are corrugated in a direction substantially transverse to the axes of rotation of the rollers, the material is positioned correctly relative to the rollers and to the cutting apparatus (when used). Figure 7 is a schematic view of an apparatus for adjusting the position of corrugations on the inner frame. Conventional cigarette packing apparatus includes machinery for cutting inner frames from a strip of card off a reel. This machinery includes, upstream of the cutter, apparatus for cutting from the inner frame, the closure tabs which retain the lid shut. This apparatus which is of known construction, and operation is shown schematically at 310 in figure 7, and comprises upper and lower rollers. The card from the reel passes through the nip between the rollers. According to the invention, upper 312 and lower 314 adjacent corrugated rollers are provided immediately downstream of the closure tab cutting rollers 310 between the tab cutting rollers and the blade 316 which cuts the inner frame from the strip of card. The corrugated rollers 312, 314, and the closure tab cutting rollers 310 are each attached at one end to respective spur gears 318, 320, 322, 324. The central axis of each gear is aligned with the axis of rotation of the roller it is attached to. A central spur gear 326 is disposed between the spur gears 320, 324 at the ends of the two lower rollers. The gears 318, 320, 322, 324, 326 are in the same plane. The spur gear on each lower roller meshes with the spur gear on the respective upper roller and with the central spur gear. The lower corrugated roller 314 is driven, and drives the upper corrugated roller and, through the central spur gear 326, the closure tab cutting rollers. A series of conventional gear linkages (not shown) connect the cutting apparatus to the driven spur gear 320 at the end of the lower corrugated roller 314. As the two pairs of rollers are rotated, the strip of card (not shown) used to make inner frames is fed into the nip between the closure tab cutting rollers 310. The sheet then passes into the nip between the corrugating rollers 312, 314. Passage of the sheet between the corrugating rollers causes the sheet to be corrugated as described before. When the sheet has passed between the corrugating rollers, it passes to the cutting blade 316, which cuts the inner frames from the strip. The inner frames are then assembled into a pack for smoking articles according to the invention. The conventional gear linkages between the gear 320 at the end of the lower corrugated roller 314 and the cutting blade 316 ensure that the action of the cutting blade is synchronised with the tab cutting and corrugating actions. Thus, the closure tabs and the corrugations are positioned correctly on the cut inner frames. The relative positioning of the components of the apparatus may be altered so that the cuts defining the closure tabs of the inner frame, the corrugations, and the sizing cut are formed in a different order. For example, the sheet may be cut to the size of the inner frame after the cuts defining the closure tabs are made, but before the sheet is corrugated. The gear linkages are adjusted appropriately so that synchronisation is maintained. The positioning of corrugations and/or closure tab-defining cuts formed on the inner frame may be altered by disengaging the gears at the end of the rollers, rotating the rollers, then re-engaging the gears. The precision of the adjustment that can be made, however, is dependent on the pitch of the gears. A further aspect of the apparatus described above is that the position of the corrugated rollers 312, 314 may be adjusted relative to their axes of rotation so that the positioning of corrugations on the inner frame can be precisely controlled. Figure 8 shows a detailed side view of the lower driven corrugated roller 314. Figure 9 shows a detailed perspective view of one end of the lower corrugated roller 314. In both figures 8 and 9, the spur gears on the roller are omitted. The roller 314 is hollow and has a cylindrical shaft 328 running through its centre. The shaft 328 is long enough to project from either end of the roller 314 and carries the spur gear (not shown). The roller can be rotated relative to the shaft. The roller is fixed to the shaft at each end by respective open rings 330, 332. Screws 334, 336 pass through a hole in each open end of the respective rings 330, 332. The hole in the open end of each ring 330, 332 that is furthest from the head of the respective screws 334, 336 is threaded. Rotation of the screws 334, 336 causes the internal diameter of the open rings 330, 332, respectively, to increase or decrease depending on the direction of rotation of the screws. The central axis of each open ring 330, 332 is aligned with the axis of rotation of the roller 314. Part of one side of one open ring 330 is attached to one end of the roller 314. The region of the side of the open ring 330 adjacent to the open ends of the ring is not attached to the end of the roller so that the open ends of the ring can move relative to one another. The other open ring 332 is similarly attached to the other end of the roller 314. The shaft 328 passes through the open rings 330, 332. The roller is fixed to the shaft 328 by tightening the screws 334, 336 in the open rings 330, 332. The position of the roller 314 relative to the shaft 328 can be adjusted manually by undoing the screws so that the internal diameter of the open rings is increased and the roller is free to be rotated relative to the shaft. The upper roller 312 is adjusted on a shaft in an identical manner. Adjustment of the rollers on their shafts allows the exact position of the troughs and ridges of the corrugated rollers to be altered relative to the angular position of the closure tab cutting rollers 310 and the position of the cutting blade 316. This allows the position of corrugations on the cut inner frame to be precisely determined. A similar mechanism of adjustment may be used to alter the angular position of the closure tab cutting rollers 310, allowing the precise position of the cuts defining the closure tabs of the inner frame to be determined. In an alternative method by which sheet material used in packs according to the invention is corrugated, the material is placed on top of a corrugated surface. Another corrugated surface is then placed on top of the material. The corrugations of the lower corrugated surface mesh with the corrugations of the upper corrugated surface. As the two corrugated surfaces come together, the material between them is itself corrugated. This method can be used to corrugate precut blanks of material which are, subsequently folded to form the pack lid and body according to the invention by the packaging apparatus; it can also be used to corrugate the material of the inner frame. Packs for smoking articles according to the invention can be made from thinner material than that used to make conventional packs, without compromising the ability of the packs to resist distorting forces that are encountered in normal use. Such packs also have the advantage that the material used to make them is more easily retained in a folded position than conventional packs. Consequently, the number of gluing points required when the packs are made are reduced. It will be appreciated that the types of corrugations described above may be applied to other types of packs than those described. For example, oval packs and blanked corner packs. They may be applied to one, some, or all corners, rounded edges, bevelled edges, or other types of edges.

Claims: A hinged lid pack for smoking articles comprising a box (12), the box comprising a body (14) and a lid (16) hinged to the body, and the pack further comprising an inner frame (18), wherein the inner frame is corrugated, characterised in that the corrugations (20) are disposed over the inner frame such that the upper rear corners of the inner frame curve inward so that they do not catch on the side walls of the lid as it is closed. A pack according to claim 1 which comprises rectangular closure tabs that project outwardly from the front wall of the inner frame wherein the corrugations are substantially transverse to the longitudinal axis of the closure tabs. A pack according to claim 2 wherein the closure tabs form an interference fit with an inner surface of the lid when it is in the closed position. A pack according to any preceding claim wherein the front wall of the inner frame is corrugated. A pack according to any preceding claim wherein the side walls of the inner frame are corrugated. A pack according to any preceding claim wherein at least one of the body and the lid is of corrugated sheet material. A pack according to claim 6 in which the body is of corrugated sheet material. A pack according to claim 6 or 7 wherein the front wall of the body is corrugated. A pack according to any of claims 6 to 8 wherein the side walls of the body are corrugated. A pack according to any of claims 6 to 9 wherein the rear wall of the body is corrugated. A pack according to any preceding claim in which the corrugations are substantially straight. A pack according to any preceding claim in which the corrugations are substantially parallel to each other. A pack according to claim 1 or according to any of claims 4 to 12 in which the corrugations, other than the inner frame corrugations when dependent from claim 2 or 3, are substantially parallel to the longitudinal axis of the pack. A pack according to any of claims 1 to 12 in which the corrugations are substantially transverse to the longitudinal axis of the pack. A pack according to any of claims 1 to 11 in which at least some of the corrugations diverge from each other. A pack according to claim 15 in which at least two lines of corrugations meet to form a chevron. A pack according to any preceding claim in which at least one of the margins of the corrugated material is not corrugated. A pack according to any preceding claim in which the height of the corrugations is between 0.1mm and 2mm measured from trough to peak. A pack according to any preceding claim in which the width of each corrugation is between 0.5mm and 4mm. A pack according to any preceding claim in which the corrugations have a substantial sine wave profile in cross section. A pack according to any of claims 1 to 19 in which the corrugations are of substantial V cross section. A pack according to any preceding claim in which the troughs of the corrugations are substantially flat. A pack according to any preceding claim in which the corrugations extend across a corner of the pack in a direction substantially transverse to the corner. A pack according to any preceding claim in which the inner frame is not integral with the box. A pack according to any preceding claim in which the body and the lid are integral. A method for corrugating a sheet of paper card (226) for use as an inner frame in packs for smoking articles which comprises: passing the sheet between adjacent rollers (210,212), wherein the curved surface of at least one of the rollers is corrugated and wherein rotation of the rollers causes their surfaces to impinge on the sheet to corrugate it; and cutting the sheet with a cutting apparatus, characterised in that the cutting apparatus and the rotation of the rollers is synchronised so that the position of the corrugations relative to the edges of the cut card can be controlled, such that when the cut card is used as an inner frame in a hinged lid pack for smoking articles the upper rear corners of the cut card curve inward so that they do not catch on the side walls of the lid as it is closed. A method according to claim 26 wherein a curved surface of each roller is corrugated. A method according to claim 26 or 27 wherein the corrugations extend across the entire curved surface of the or each roller. A method according to any of claims 26 to 28 wherein the sheet moves relative to the axis of rotation of the rollers. A method according to any of claims 26 to 28 wherein the axis of rotation of the rollers moves relative to the sheet. A method according to any of claims 26 to 30 wherein the sheet is cut after it has been corrugated. A method according to any of claims 26 to 30 wherein the sheet is cut before it is corrugated. A method according to any of claims 26 to 32 for making an inner frame for a pack of cigarettes. A method according to claim 33 in which prior to or after corrugation the card is passed between another pair of rollers (310) which modifies the card and in which the making of the cut is synchronised to the corrugation of the card. A method according to claim 33 or 34 in which the card is cut to form inner frames after it has been corrugated and in which the said cutting is synchronised to the corrugation of the card. Apparatus for corrugating a sheet of paper card for use as an inner frame in packs for smoking articles comprising: a pair of adjacent rotatable rollers (210,212), wherein the curved surface of at least one of the rollers is corrugated; and a cutter for cutting the card, characterised in that the rotation of the rollers and the operation of the cutter is synchronised so that the position of the corrugations relative to the edges of the cut card can be controlled, such that when the cut card is used as an inner frame in a hinged lid pack for smoking articles the upper rear corners of the cut card curve inward so that they do not catch on the side walls of the lid as it is closed. Apparatus according to claim 36 wherein the curved surface of each roller is corrugated. Apparatus according to claim 36 or claim 37 wherein the corrugations extend across the entire curved surface of the or each roller. Apparatus according to any of claims 36 to 38 wherein the corrugations have a sine wave profile in cross section. Apparatus according to any of claims 36 to 38 wherein the corrugations have a saw-tooth profile in cross section. Apparatus according to any of claims 36 to 40 wherein the troughs of the corrugated surfaces are substantially flat. Apparatus according to any of claims 36 to 41 for forming inner frame blanks for packs of smoking articles from a strip of card, further comprising: a second pair of adjacent rollers (310) for modifying the card; wherein the rotation of the first and second pairs of rollers and the operation of the cutter is synchronised. Apparatus according to claim 42 wherein the rollers and the cutter are coupled together by gears to synchronise their rotation and operation. Apparatus according to claim 42 or 43 wherein the second pair of rollers cut the card to form closure tabs. Apparatus according to claim 42, 43, or 44 in which each roller is mounted on a rotatable shaft (328). Apparatus according to claim 45 in which the shaft of one of the second pair of rollers is geared to and the cutter is coupled to the shaft of one of the corrugated rollers. Apparatus according to claim 45 or 46 in which at least one of the rollers is rotatable relative to its shaft. Apparatus according to claim 47 in which a clamp is affixed to the or each roller rotatable relative to its shaft which releasably attaches the roller to the shaft. Apparatus according to claim 48 in which the clamp comprises an open ring (330) attached to the roller such that at least one end of the ring is free to move and a threaded rod (334) extending between the free ends of the ring so that rotation of the rod changes the internal diameter of the open ring so that it can be clamped onto or released from the shaft.

Inventors: BORGOGNON PIERRE, BORGOGNON, PIERRE
Applicants: PHILIP MORRIS PROD, PHILIP MORRIS PRODUCTS S.A.
Application year: 1998
Main classification: B65D85
IPC codes: B65D65, A24F15, B65D85, B31F1