Patent Publication Number: US-6988617-B2

Title: Bottom locking carton

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a wrap-around can carton with open ends, which has retaining flaps in the upper corners on each end with bottom locks that lock into the indentation in the bottom ends of the cans to prevent the cans from falling out. This carton may have locks for securing the bottom flaps of the carton together. 
     2. Prior Art 
     Wrap-around cartons have been used in the past. When fabricating a carton from a paperboard blank, opposite sides of the blank are conventionally attached to each other by glue or by mechanical locks to form the bottom panel of the carton. In the case of a wrap-around carton, flaps located on the sides of the blank typically are overlapped and engaged with one another by mechanical locks formed in the flaps to form the bottom panel of the carton. Since the bottom panel must maintain its integrity throughout the use of the carton, it is essential that the locking system by capable of supporting the weight of the packaged articles, and remain engaged during shipping and handling of the constructed carton. 
     One approach to provide such a stable mechanical lock assembly utilizes primary and secondary locks. The primary locks connect the ends of the carton together via the flaps, while the secondary locks function to maintain the engaged flaps in place in order to provide a “backup” locking system to prevent the primary locks from separating. A superior locking system that overcomes many of the deficiencies of prior art locks is disclosed in U.S. Pat. No. 5,443,203 to Sutherland, which describes a mechanical locking system that does not require secondary male locking tabs to extend beyond the end edges of the blank, but which system effectively locks the tabs in place and resists withdrawal of the tabs. 
     U.S. Pat. No. 4,708,284 (Sutherland, et al.) issued on Nov. 24, 1987 discloses a locking arrangement including both primary and secondary male locks which utilizes a single female aperture for receiving both the primary and secondary male lock. 
     It would be advantageous to provide a wrap-around carton with open ends which has some means of holding the bottoms of the cans in place so they do not fall out of the open ends of the carton. This would reduce the amount of paperboard required to produce the carton as the carton has open ends. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an open ended wrap-around carton for cans that has retaining flaps in the upper corner of each end of the carton and some means of holding the bottoms of the cans in place without the necessity of having retaining flaps on the bottom of the carton. 
     It is the further object of this invention to provide a mechanism for holding cans that have an indentation in the bottom of the can for utilizing the indentation to hold the bottom of the can securely within the carton. It is a further object of this invention to provide a open ended carton for holding cans that does not require retaining flaps at the corners at the bottom of each end of the carton, which would require more paperboard to produce the carton. It is another object of this invention to achieve these objectives with a carton that has a primary and secondary locking system. 
     These objects are achieved by providing a wrap-around carton for containing cans with an indentation in the bottom of the cans, which in its preferred embodiment has a top panel, side panels and bottom flaps with a locking system for locking the carton together. This carton has a retaining flap at each top corner of the carton that is held in place by a tuck-in panel that is wedged between the can adjacent the end and the side panel. The bottom flaps are held together by primary and secondary male locks in one bottom flap that are locked into a single female opening in the other bottom flap that has a primary female locking ledge and a secondary female locking ledge holding the primary and secondary locks engaged. 
     This wrap-around carton is designed to be used with cans that have an indentation in the bottom surrounded by a rim. A locking tab is struck from a bottom flap and adjoining side panel to fit inside the indentation in the bottom of an adjacent can. This locking tab has a curved outside edge which fits against the inside curved bottom rim of a can. The locking tab is held in position securely against the bottom curved rim of the can by a holding tab which is foldably connected to the locking tab. The holding tab is foldably connected to the bottom flap which is connected to the side panel. This holding tab should have a height that is not significantly higher than the height of the indentation in the bottom of the can, and preferably is significantly less than the height of the indentation. The locking tab preferably has a diameter much less than the diameter of the indentation in the bottom of the can, and may be less than one-half (½) the diameter of the indentation and may be as small as approximately one-fourth (¼) of the diameter of the indentation. 
     During the forming of the wrap-around carton, a compression finger pushes the locking tab into position in the indentation of an adjacent can. The compression finger first pushes the locking tab in along the fold line between the locking tab and the holding tab. The compression finger continues pushing on the locking tab and pushes the curved end of the locking tab against the inside of the curved rim in the bottom of the can closest to the side panel. The final pushing is along the fold line between the holding tab and bottom flap which tightens the carton around the cans. The compression finger is then removed and the locking tab is held firmly in position by the holding tab. A cross section of the locking tab, holding tab and bottom flap is in a Z configuration. 
     Preferably, in this wrap-around carton retaining flaps and tuck-in panels hold the tops of the cans in position. Only the locking tabs hold the bottom ends of the cans in the carton. 
     This carton is preferably a locked carton with primary and secondary locks utilizing a single aperture that has a primary female locking ledge and a secondary female locking ledge. The bottom locks are preferably used with cartons containing containers arranged in two rows. It should be understood that this wrap-around carton using locking tabs to secure the bottom of cans could utilize other locking systems or could be glued. In addition other types of retaining means could be used to hold the top ends of the cans securely in position in the carton. The bottom lock of this invention could be used with other types of containers, such as square containers, with an indentation surrounded by a rim in the bottom. In this case the locking tab preferably has a straight end. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view of a blank for a wrap-around carton which incorporates the features of an embodiment of the present invention. 
         FIG. 2  is a partial view of the bottom of the wrap-around carton made from the blank of  FIG. 1  which shows a compression finger attached to a lug on a wrapping machine (not shown)pushing the locking tab into the locked position. 
         FIG. 3  is a view of the bottom of the cans with the bottom flap having been pushed partly into position and the locking tab having being pushed partly into a position in the indented bottoms of one row of cans. 
         FIG. 4  is a partial view of one bottom flap of the wrap-around carton made from the blank illustrated in  FIG. 1  showing three of the locking tabs in the locked position in the indented bottoms of the cans in one row of cans. 
         FIG. 5  is a perspective view of the wrap-around carton made from the blank of FIG.  1  and loaded with cans. 
         FIG. 6  is a cross sectional view taken along line  6 — 6  in  FIG. 5  of one holding tab in a bottom flap that is in the locked position in the indented bottom of a can. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention is intended primarily for use with wrap-around cartons containing cylindrical containers, such as cans, used to contain soft drink, beer, and the like. A typical example of such a can C is illustrated in FIG.  3 . This can has an indented bottom B and a bottom curved rim R as illustrated in FIG.  3 . The can may have a typical top with a tab for opening the can to pour out the contents. 
     The blank for forming the carton of the preferred embodiment is illustrated in FIG.  1 . The blank  10  is designed to contain six beverage cans C in two rows of three each. The blank  10  is formed from a foldable sheet material, such as paperboard. The blank  10  has a bottom flap  12  which is foldably connected to side panel  14  by fold line  16  and in turn connected to top panel  18  by fold line  20 . The top panel  18  is connected to side panel  22  by fold line  24  and in turn connected to bottom flap  26  by fold line  28 . The top panel may have a tear line  30  forming an opening flap  32 , that when removed provides easy access to the cans C. Finger flaps  34  may be formed in the top panel  18  by tear lines  36 . These finger flaps  34  may have crease lines  38  so that when a person wishes to carry the wrap-around carton the finger flaps  34  can be easily pushed in and then carried by a person&#39;s finger and thumb. 
     It will be understood by those in the art that the preferable blank  10  is symmetrical about a horizontal line of bisection, as viewed when  FIG. 1  is rotated lengthwise. This symmetry aids in the efficient production of the present wrap-around carton. The carton need not have such symmetry, although it is preferred. As shown, the blank is rectangular and includes straight edges, which makes for an efficient layout of the blanks in a web from which the blanks are cut. 
     In order to hold the tops of the cans C from falling out of the wrap-around carton formed from the blank of  FIG. 1 , retaining flaps  40 A-D may be formed at the four upper corners of the carton. These retaining flaps  40 A-D are foldably attached to the top panel  18  by fold lines  44  and each is attached to a tuck-in panel  42 A-D by fold line  46 . The tuck-in panels  42 A-D are in turn attached to side panels  14  and  22  by fold lines  48 . A stress aperture  50  may be formed between each retaining flap  40 A-D and respective tuck-in panel  42 A-D and the adjacent side panel  14  or  22 . 
     A bottom lock  52 A-F is formed in bottom flaps  12  and  26  for holding the bottoms of the cans C. Each bottom lock  52 A-F has a locking tab  54 A-F which is struck largely from the bottom flap  12  or  26 , but a portion may be struck partially from the adjacent side panel  14  or  22 . Each bottom lock  52 A-F has a holding tab  56 A-F which is connected to the locking tab  54 A-F by fold line  58 . A tear line  60  which extends around each locking tab  54 A-F and the sides of the holding tab  56 A-F for the folding of the bottom lock into position is provided. The holding tab  56 A-F is foldably attached to the bottom flap  12  or  26  by fold line  62 . 
     A wrap-around carton of this invention may be glued together or may have a conventional locking system. The locking system shown in the preferred embodiment includes both a primary locking and a secondary locking system. The primary and secondary male locks are formed in bottom flap  26 . Primary male locks  64 A-B are formed in bottom panel  26  by cut line  65 . The primary male locks  64 A-B are separated by fold line  66 . Secondary male locks  68 A-B are formed as an extension of bottom flap  26  and may have a fold line  70  to facilitate locking. 
     In the embodiment illustrated in  FIG. 1 , a single female opening  72 A-B is provided for locking each set of primary male locks  64 A-B and secondary male locks  68 A-B. Each female opening  72 A-B has a primary female locking ledge  74 A-B for locking a primary male lock  64 A-B. In addition, each female opening  72 A-B has a secondary female locking ledge  76 A-B which may have secondary female locking slits  78  for receiving the secondary male locks  68 A-B. 
     During the locking of the blank  10  illustrated in  FIG. 1  the primary male locks  64 A-B are hooked over the primary female locking ledges  74 A-B during the locking of the carton. The primary male locks  64 A-B connects the ends of the wrap-around carton together via bottom flaps  12  and  26 . 
     The secondary locking system consists of secondary male locks  68 A-B and secondary female locking ledges  76 A-B. The secondary locking system is basically a “back-up” locking system for the primary locking system. It should be understood that other locking systems may be used for the wrap-around carton of this invention. For example, in place of having a single female opening  72 A-B for both the primary male lock  64 A-B and the secondary male lock  68 A-B, a primary female aperture and the second female aperture may be used to secure the primary male locks and secondary male locks (not shown). 
     It should be understood that other locking systems may be used for this wrap-around carton. In addition, this carton may be secured together by glue. 
     The wrap-around carton of this embodiment of the invention is formed from the blank of  FIG. 1  by moving the top panel  18  of the blank over the top of six cans C and in the process fingers on the wrap machine push tuck-in panel  42 A-D so that it is wedged between a can C at an open end of the carton and an adjacent side panel  14  or  22 . This results in pulling the attached retaining flap  40 A-D around a portion of the top of the can C as illustrated in FIG.  5 . 
     The side panels  14  and  22  are folded along the sides of the can C and the bottom flaps  12  and  26  folded along fold lines  16  and  28 , respectively, over the bottoms of the cans. A compression finger  80  attached to a lug  82  on the wrap machine pushes each holding tab  56 A-F inwardly into the carton wrap and pushes along fold line  58  until the locking tab  54 A-F is pushed into a snug fit in the indented bottom B of the can C as illustrated in  FIGS. 2 ,  4  and  6 . Each locking tab  54 A-F has a curved outside edge D that fits inside the indented bottom B of the can C and rests against the bottom curved rim R of the can C that is adjacent to the side panel  14  or  22  in bottom flap  12  or  26  from which the respective bottom lock  52 A-F is struck. This results in each bottom lock  52 A-F fitting in to the indented bottom B of the can C as illustrated in the cross-sectional view shown in FIG.  6 . When the final locking of the wrap-around carton is complete this curved outside edge D of a locking tab  54 A-F fits snugly against the bottom curved rim R of the can, which results in holding the bottom B of the can C securely in the wrap-around carton. As illustrated in  FIG. 6 , the locking tab  54 A, the holding tab  56 A and the bottom flap  12  form a Z configuration in a cross-sectional view. 
     The wrap-around carton is locked by pushing the primary male locks  64 A-B into the respective female openings  72 A-B securing the primary male lock  64 A-B over the primary female locking ledge  74 A-B. At the same time secondary male locks  68 A-B are hooked over the secondary female locking ledges  76 A-B with their ends being pushed through secondary female locking slits  78 . Compression finger  80  may be pushed against the fold lines  62  to complete the tightening of the wrap-around carton. When finished wrapping, a portion of bottom flap  26  lies outside of bottom flap  12 . 
     The tops of the cans in each open end of the carton are held within the carton by retaining flaps  40 A-D extending around an outside portion of the top of the can C as illustrated in FIG.  5 . The respective tuck-in panel  42 A-D is wedged between the respective side panel  14  or  22  and the top of an adjacent can C. Because this tuck-in flap is wedged between a side panel and can, it holds the retaining flap firmly in position, holding the top of the can C securely within the wrap-around carton. As this wrap-around carton is tightened securely around the cans, the pressure between two adjacent cans on each end of the carton prevents the cans in each open end from falling out. It should be realized that other types of retaining mechanism, including other types of flaps, may be used to retain the tops of the cans securely within the wrap-around carton. 
     The bottoms of the cans C are held in position by bottom locks  52 A-F. It is preferred that the bottom locks be inserted into the indented bottom B of all the cans. However, it is essential that these bottom locks  52 A-F be inserted into the indented bottom B of all the cans C adjacent the open ends of the wrap-around carton. 
     As pointed above the compression finger  80  held by a lug on the wrap machine pushes the locking tab  54  and the holding tab  56  inwardly as illustrated in FIG.  2 . This process is completed before the primary and secondary locking systems are engaged. The completion of the step of engaging the locking tab  54  is illustrated in  FIG. 3  which is a view of the bottom of the cans in which the locking tabs  54 A-C have been pushed into position on one row of cans. As illustrated in  FIG. 4  the locking tabs  54 A-C with a curved outside edge D fits snuggly against the inside surface of the bottom curve rim R of a can C. It will be noticed from  FIG. 4  that the locking tab  54 A-F fits against the inside surface of a bottom curved rim R of the can that is immediately adjacent to side panel  14 . It is important that holding tabs  56 A-F have a height H as illustrated in FIG.  1  and  FIG. 6  that fits within the indented bottom B of the can C as illustrated in FIG.  6 . This height H is preferably less than the height of the indented bottom B of the can. However it should be pointed out that the height could be somewhat greater than the height of the indented bottom B of the can, which would result in some crushing of the holding tab  56 A-F. However the height H of the holding tab  56 A-F cannot be significantly greater than the height of the indented bottom B of the can. 
     The locking tabs  54 A-C as illustrated in  FIG. 4  have a curved outside edge D that is held firmly against the inside surface of the curved rim R of the can C. The holding tab  56  has a memory that tends to push it back into the plane of the blank as illustrated in  FIGS. 1 and 6 . The distance between the curved outside edge D and fold line of each locking tab  54 A-F must be less than the diameter of the indented bottom B of the can C between the inside surfaces of the bottom curved rim R of the can. Preferably the distance between the curved outside edge D of each locking tab  54 A-F and fold line  58  is less than half the diameter of the bottom of the can C between the inside surfaces of the bottom curved rim R of the can as illustrated in FIG.  3 . Preferable the distance between the curved outside edge D of the locking tab  54 A-A and fold line  58  is one fourth or less of the diameter of the indented bottom B of the can between the inside surfaces of the bottom curved rim R of the can. The locking tab  54 , holding tab  56  and bottom flap  12  or  26  form a Z configuration when viewed in cross section as shown in FIG.  6 . 
     While the bottom lock of this invention is shown in an embodiment with cans, it should be realized that the bottom lock could be used with other types of containers (e.g. having a square bottom) as long as the container has a bottom indentation into which a locking tab can be inserted. It is preferable that the outside edge of the locking tab is of the same configuration as the inside rim of the container it is designed to hold. 
     Thus, the combination of the bottom lock of this invention, which holds the bottom of the cans in place, and the top retaining flaps which holds the tops of the cans from falling out results in producing a tightly packed wrap-around carton that secures the cans snugly within the wrap-around carton. 
     This is a very economical wrap in that there is no necessity to enclose the ends of the carton and the bottoms of the cans are held in position by the bottom locks which otherwise would be wasted material as the aperture formed by the bottom locks would be necessary to provide a place through which the compression fingers of the wrapping machine could be inserted to tightly wrap the wrap-around carton around the cans. Thus, a wrap-around carton that securely holds the cans in place is provided, which greatly reduces the amount of paperboard used to construct the carrier. While this embodiment shows the carton being used with six cans, it should be realized that it could be used with four cans or more than six cans as long as they are in two rows. 
     It should be realized that the geometry between the locking tab  54  and the holding tab  56  and the indented bottom of the can is important so that the holding tab retains its memory and tends to push the locking tab back into the plane in which it was formed in a blank. 
     It should be emphasized that the above-described embodiments of the present invention, particularly, any “preferred” embodiments, are merely possible examples of implementations, merely set forth for a clear understanding of the principles of the invention. Many variations and modifications may be made to the above-described embodiment(s) of the invention without departing substantially from the spirit and principles of the invention. All such modifications and variations are intended to be included herein within the scope of this disclosure and the present invention and protected by the following claims.