Abstract:
A carton and blank having a tear line comprising a plurality of perforations or short slits arranged in at least three rows. There is also provided a carton and blank for forming a carton having a wall provided with a tear open feature which comprises a tear initiating means formed in the wall and at least three tear lines extending from the tear initiating means toward the perimeter of the wall, wherein each tear line comprises a plurality of perforations or short slits arranged in at least three rows.

Description:
[0001]     This is a continuation of international application No. PCT/US03/04146, filed Feb. 10, 2003, which is hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The invention relates to a carton or sleeve for accommodating one or more articles for example cans, bottles or the like formed from one or more blanks of paperboard or other suitable foldable sheet material and more particularly to a carton capable of being formed into a sealed compartment including a cover flap with mean for releasably fastening the cover flap to the carton.  
         [0003]     The invention is particularly useful where it is desirable for cartons containing articles to be enclosed to protect the or each article.  
         [0004]     One example of reclosable sleeves formed from one or more blanks of cardboard is found in U.S. Pat. No. 3,078,030, which illustrates a carton having integral hinged top that is reclosable. The top is provided by a front cover panel and a spacer panel secured to one side of the front cover panel to interfit with a mating upper portion of the front panel of a box. Fastening means is formed from a detached double layer portion of the front panel. However, the detached portion is attached to the inside surface of the cover flap resulting in a stepped non-flat front surface.  
         [0005]     A second aspect of the invention is concerned with the provisions of a frangible connection for releasably fastening the cover flap. More particularly, a tear strip arrangement is disclosed.  
         [0006]     There are several known types of tear line in common use, examples of which are illustrated in U.S. Pat. No. 2,28,552 or U.S. Pat. No. 3,355,089. However, one problem associated with known tear lines or strips is that the action of tearing is difficult to control. For example, the grain direction of the board or direction of tearing force will influence the tear direction.  
         [0007]     To try to encourage tearing along a predetermined path tear lines are used.  
         [0008]     A problem with known tear arrangements is that, in certain circumstances the tear may deviate from the desired path leading to an irregular tear line path or worse, deviation from the tear line completely which may result in destroying the integrity of the carton.  
       SUMMARY OF THE INVENTION  
       [0009]     A first aspect of the invention provides a carton having a tear line comprising a plurality of perforations or short slits arranged in at least three rows  
         [0010]     Optionally, the perforations or slits of each row is offset the perforations or short slits of the next adjacent row.  
         [0011]     Preferably, the perforations in a row are spaced by a distance in the range of about 1 mm to 5 mm. More preferably, each row is spaced from the next adjacent row by a distance of about 0.5 mm to 2.5 mm.  
         [0012]     A second aspect of the invention provides a carton having a wall provided with a tear open feature which comprises a tear initiating means formed in the wall and at least three tear lines extending from the tear initiating means toward the perimeter of the wall, wherein each tear line comprises a plurality of perforations or short slits arranged in at least three rows.  
         [0013]     The tear open feature may comprise four tear lines extending towards the four corners of the wall respectively.  
         [0014]     Optionally, the tear initiating means comprises a push tab struck from the wall.  
         [0015]     A third aspect of the invention, in a carton formed from paperboard or other sheet material of like function, a tear structure which defines a join between two adjacent panels, means to grasp a panel to be torn away defined, at least in part, by said tear structure so that it can be displaced out of the plane it occupies at rest and fold lines disposed between said means and said tear structure to enhance the amount by which said tear away panel can be displaced so that shear forces exerted on the tear structure are sufficient to cause tearing at the tear structure whereby the tear away panel can be removed from the carton.  
         [0016]     According to an optional feature of the third aspect, the tear away panel provides access to the carton contents when removed.  
         [0017]     Preferably, the tear away panel is a top panel of the carton and wherein the tear structure extends around the periphery of that panel and wherein said means for grasping the panel is disposed remote from its periphery, said fold lines extending from said means in a multiplicity of directions to meet said tear structure at a plurality of locations.  
         [0018]     More preferably, said tear structure comprises at least two adjacent perforate lines wherein the perforations in one of said lines are disposed intermediate the perforations in the next adjacent line and wherein the spacing between said adjacent lines is no greater than the spacing between the perforations of either one of them.  
         [0019]     A fourth aspect of the invention provides a blank for forming a carton having a tear line comprising a plurality of perforations or short slits arranged in at least three rows. In the blank, the perforations or slits of each row is offset the perforations or short slits of the next adjacent row. Preferably, the perforations in a row are spaced by a distance in the range of about 1 mm to 5 mm. More preferably, each row is spaced from the next adjacent row by a distance of about 0.5 mm to 2.5 mm. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]     Exemplary embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:  
         [0021]      FIG. 1  is a plan view of a blank for forming a carton incorporating the tear line arrangement according to a first embodiment of the invention;  
         [0022]      FIG. 2  is a perspective view of the carton formed from the blank illustrated in  FIG. 1  in a set-up and loaded condition;  
         [0023]      FIGS. 3 and 4  illustrate the carton with the cover flap partially torn open;  
         [0024]      FIG. 4   a  is an enlarged view of the tear strip feature;  
         [0025]      FIG. 5  illustrates a blank according to a second embodiment of the invention;  
         [0026]      FIG. 6  illustrates a perspective view of the carton formed from the blank of  FIG. 5  in a set-up and loaded condition; and  
         [0027]      FIG. 7  illustrates the carton of  FIG. 6  with the cover panel fully torn open. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0028]     Referring first to  FIG. 1 , there is shown a unitary blank  10  for forming a carton made from paperboard or similar foldable sheet material. The carton is adapted to hold one or more articles. In this embodiment the blank  10  comprises a base panel  12 , first side wall panels  14 , top panel  16  and second side wall panel  18  hingedly connected together in series along fold lines  20 ,  22  and  24  respectively.  
         [0029]     There may further comprise opposed end wall panels  26 ,  30  hingedly connected to the opposed end edges of base panel  12  along fold lines  28  and  32  respectively. In this embodiment, the base panel is substantially square although it is envisaged that other shapes of the base panel and/or sleeve can be adopted according to the shape and/or size of the article(s) to be contained.  
         [0030]     In those embodiments with end wall panels  26  and  28 , there further comprises opposed end flaps  34  and  38  hingedly connected to opposed edges of top panel  16  along fold lines  36  and  40 .  
         [0031]     In this embodiment, the support flaps are provided along the longitudinal edges of the side wall panel  14  and  18  respectively. As shown in  FIG. 1 , there comprises side flaps  42   a  and  42   b  hingedly connected to the opposed edges of side panel  14  along fold lines  44   a  and  44   b . Similarly, end flaps  42   c  and  42   d  are hingedly connected to the opposed edges of second side wall panel  18  along fold lines  44   c  and  44   d.    
         [0032]     There further comprises a securing flap  46  hingedly connected to base panel along fold line  48 , to secure the opposite ends of the blank together. The securing flap  46  may be provided with fold lines  50  and  52 .  
         [0033]     One aspect of the invention provides a one or more detachable cover flaps formed in the top wall panel  16 . In this embodiment there comprises four cover flaps  54 ,  56 ,  58  and  60  provided to cover the top surface of the carton. The cover flaps are hingedly connected to the carton both along fold lines  22 ,  40 ,  24  and  36  respectively.  
         [0034]     The cover flaps are frangibly interconnected together by frangible lines: so in this embodiment, cover panel  54  is frangibly connected to cover panels  56  and  60  along frangible lines  66  and  68 . Likewise, cover panel  58  is frangibly connected to cover panels  60  and  56  along frangible lines  62  and  64 .  
         [0035]     The cover flaps are, in this embodiment, triangular in shape although other polygonal shaped are envisaged without departing from the scope of invention. In order to assist in separating adjacent cover flaps, there further comprises a push tab  70 , which is detachably connected to the top panel. In  FIG. 1  the tab  70  is centrally positioned at the point the frangible lines  62 ,  64 ,  66 ,  68  interconnect.  
         [0036]     At each of the opposing ends of frangible lines  62 ,  64 ,  66  and  68 , there is provided a fold line  62   a ,  62   b ;  64   a ,  64   b ;  66   a ,  66   b ;  68   a ,  68   b  bisecting the frangible lines shown in  FIG. 4 . The fold lines prevent the tearing from going beyond the ends of the frangible lines, by dissipating the tearing forces.  
         [0037]     Another aspect of the invention relates to the structure of the frangible lines  62 ,  64 ,  66  and  68 .  FIGS. 4 and 4 A illustrate the preferred embodiment of tear line  68  which are formed from three or more individual rows  72 ,  74   76  comprising a plurality of perforations or short slits. In each row, a perforation is spaced from the next adjacent perforation by a distance L. The distance L will vary according to particular tear characteristics, although it has been found that a usable range of distance L is between approximately 1 and 5 mm. Each row  72 ,  74 ,  76  is also spaced from the next adjacent row by a distance C. The distance C will vary according to particular tear characteristics required, although it has been found that a usable range of distance C is between approximately 0.5 and 2.5 mm.  
         [0038]     Each row of perforations is offset the next row so that the perforations appear to have a “stair” shape as shown in  FIG. 4A .  
         [0039]     In use, the tear line  68  has been found to be more effective than a tear strip with one or two rows of slits because the central row of perforations  74  transmits the tear along its length—the force of the tear passes through this central line. The shearing forces are then applied across one side or the other side of the central row  74  to tear the space C between the central row  74  and the outer rows  72  and  76 , as the tear moves along the tear line.  
         [0040]     Thus, it far easier to control the direction of tearing by allowing a degree of flexibility as to where tear takes place within the outer rows.  
         [0041]     One advantage of this type of tear line is that it is possible to produce a rounded tear strip, for example to follow the shape of the logo on the advertising indicia printed onto the board.  
         [0042]     It is envisaged that any of the embodiments of the carton of the present invention can be formed by a series of sequential folding and gluing operations, which can be formed in a straight-line machine so that the carton is not required to be rotated or inverted to complete its construction. The folding process is not limited to that described below and can be altered according to particular manufacturing or user requirements. For example, the carton could be part constructed whereby side panel  18  and securing flap  50  are secured together to form a tubular structure before loading it with articles.  
         [0043]     The base wall panel  12 , opposed side wall panels  14 ,  18  and top panels  16  are folded out of alignment along fold lines  20 ,  22  and  24  and are folded into a tubular structure and securing flap  46  is secured to side panels  18  by glue or other means known in the art.  
         [0044]     The article(s) is loaded into the carton by known packaging means.  
         [0045]     The support flaps  42  are folded inwardly along fold lines  44  and the opposing ends are constructed by folding end wall panels  26  and  30  upwardly along fold lines  28  and  32  respectively. Likewise the end flaps  34  and  38  are folded downwardly along fold lines  36  and  40  and the outer face of the end flaps  34  and  38  are secured to the inner face of end wall panels  26  and  30  by glue or other means know in the art. Thus the carton is in a set up and loaded condition as shown in  FIG. 2 .  
         [0046]     In order to gain access to the interior of the carton the push tab  70  is depressed inwardly by the user to reveal an edge  71  which is gripped by the user to tear one of the cover flaps  56  in an upward and outward direction as shown in  FIG. 3 . As the cover flap  56  continues to be pulled outwardly the tear lines  64  and  66  tear to reveal an access aperture A. The tearing process corresponds to that described above and illustrated in  FIGS. 4 and 4 A.  
         [0047]     A second embodiment is illustrated in  FIGS. 5, 6  and  7 , which embodiment shares many identical panels and fold lines so like parts have been designated by the same reference numerals with the prefix ‘1’. Therefore, only the differences will be described in any greater detail.  
         [0048]     The carton blank  110  is provided with a unitary cover panel  116  hingedly interconnecting side wall panels  114  and  118 . The unitary cover panel  116  is substantially square in shape being defined along its edges by tear lines  162 ,  164 ,  166  and  168 . In some embodiments, there further comprises one or more fold lines  167 ,  169 ,  171 ,  173  to direct the lifting forces, described in more detail below. A push tab  170  is provided in the central region of the cover panel  116 , although in other embodiments it could be positioned close to one corner of the cover panel to help with starting the tearing off from that corner.  
         [0049]     The construction of the second embodiment is identical to the first embodiment as shown in  FIG. 6 , so shall not be described in any greater detail.  
         [0050]     In order to remove the cover panel, the push tab  170  is depressed to reveal an aperture. Thereafter the user inserts a finger into the aperture and pulls the cover flap  116  which is then detached from the remaining panels of the carton by tearing along tear lines  162 ,  164 ,  166  and  168 , as shown in  FIG. 7 . One advantage of this arrangement is that the cover flap is removed from the carton with a single pulling action.  
         [0051]     Beneficially the embodiments of the invention hereinbefore described provided a structure that is sufficiently strong to retain articles and to provide an integral sleeve or enclosed carton. The use of paperboard material provides an environmentally alternative to cartons made from plastic material and the sleeves made from paperboard can include printed matter for marketing purposes.  
         [0052]     It will be recognized that as used herein, the terms “top”, “bottom”, “side”, “end”, “upper” and “lower” with respect to the panels of the carton (or carton blank) are relative terms, and that the carton (formed from the blank) may be re-oriented as necessary or as desired. It will be further recognized that rather than the bottom wall being formed from the interlocked panels, the carton blank may be rearranged whereby some other wall such as a top wall or a side wall is formed from the interlocked panels.  
         [0053]     Any reference to hinged connection should not be construed as necessarily referring to a single fold line only: indeed it is envisaged that hinged connection can be formed from one or more of one of the following, a score line, a frangible line or a fold line, without departing from the scope of invention.  
         [0054]     The invention and its preferred embodiment relate to a carton or a sleeve which is shaped to provide satisfactory rigidity to hold items such as information discs for example floppy or zip discs or foodstuff with a degree of flexibility. The shape of the blank minimizes the amount of paperboard required for the carton. The carton can be constructed from a flat collapsed condition to position of use and/or loaded by hand or automatic machinery. It is anticipated the invention can be modified without departing from the scope of the invention: for example, side and end panels can be increased in height or width to provide a carton to receive one or more articles of different shapes and/or sizes. Additionally, the tear lines shown in the various embodiments can be applied to other known carton types, for example a fully enclosed carton or wraparound cartons for beverage containers or for foodstuffs, without departing from the scope of invention.