Carton with self locking keel

Abstract: A carton has a box keel structure (K) to separate adjacent rows of articles and to retain articles in position. The box keel structure carries a locking tab (38) which is caused to ride over and engage against a ridge (40) formed in a base panel of the carton when the keel is set up from a collapsed to an upright position to maintain the keel upright.

Description: This invention relates to a carton, more usually of the wraparound type, which incorporates an article separating keel which is self supporting once the keel has been erected. So called box keels in wraparound cartons have been known for some time. A box keel usually is an integral part of the carton blank and functions as both a separator for keeping lower portions of the articles in one row thereof separated from lower portions of the articles in an adjacent row and as a retention device for retaining lower portions of the articles against movement. In one known arrangement, a first row of articles, e.g. plastics flanged cups, was set in position on a bottom panel of the carton sleeve whereafter the box keel was erected into engagement with the first row of cups and thereafter the second row of cups was put into engagement with the opposite side of the box keel and the formation of the carton then completed. FR-A-1436066 discloses a carton a blank and a method according to the first part of the respective independant claim having a keel structure for separating individual cartons comprising side walls having apertures which engage the articles and additional apertures which cooperate with a locking tab provided by a carton base panel. The locking tab is hinged about a fold line into engagement with the locking aperture after the keel is erected. In the present invention the keel is self-sustaining once it has been erected so that it can be pre-erected prior to loading and formation of the carton. The invention provides a carton for a plurality of articles which carton has a box keel structure in which the box keel serves as an article separator and/or retention device, in which cooperating locking means is provided in part by said keel structure and in part by a panel of said carton from which the keel depends, said cooperating locking means being automatically engaged as a consequence of erecting said keel structure thereby to maintain the keel structure in an erected position within said carton in the absence of said articles. According to a feature of the invention said cooperating locking means may comprise a locking tab carried by said keel and a raised formation in a base panel of said carton, said locking tab and said raised formation being positioned for engagement when said keel is substantially fully erected. In constructions where the locking means includes a raised formation it may comprise a ridge formed by indenting said base panel from the face thereof remote from said keel. In constructions where such a ridge is provided, a free edge of said locking tab which faces downwardly when said keel is erected may be caused to override said ridge to engage against a side surface thereof. According to another feature of the invention said locking tab may be formed at a lower edge of a side wall of said keel structure. In constructions where the locking tab is formed at the lower edge of a side wall, a securing flap may be hinged to said side wall, said securing flap being secured in superposed relation on a base panel and said locking tab being struck from said securing flap adjacent the hinged connection between said securing flap and said side wall. Another aspect of the invention provides a carton blank for forming a carton for a plurality of articles comprising means for forming a box keel structure in the carton in which the box keel serves as an article separator and/or retention device, cooperating locking means provided in part by said keel structure means and in part by a panel of the blank from which the keel structure means depends, characterised in that said cooperating locking means is automatically engaged as a consequence of erecting said keel structure in said carton thereby to maintain the keel structure in an erected position within said carton in the absence of said article. Said cooperating locking means can comprise a locking tab carried by said keel and a raised formation in a base panel of said blank, said locking tab and said raised formation being positioned for engagement when said keel is substantially fully erected, and preferably wherein said raised formation comprises a ridge formed by indenting said base panel from the face thereof remote from said keel, and more preferably a free edge of said locking tab which is adapted to face downwardly when said keel is erected can also be adapted to be caused to override said ridge to engage against a side surface thereof during erection. Said locking tab can be formed at a tower edge of a side wall of said keel structure, and preferably a securing flap can be hinged to said side wall, said securing flap being secured in superposed relation on a base panel and said locking tab being struck from said securing flap adjacent to the hinged connection between said securing flap, and said side wall. A further aspect of the invention provides a method of erecting a keel structure in a carton having a box keel structure in which the box keel serves as an article separator and/or retention device, in which cooperating locking means is provided in part by said keel structure and in part by a panel of said carton from which the keel depends, said cooperating locking means being automatically engaged as a consequence of erecting said keel structure thereby to maintain the keel structure in an erected position within said carton comprising the step of moving the keel from a collapsed position beyond its erected position and back to its erected position thereby to effect engagement of said cooperating locking means in the absence of said articles. An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:- FIGURE 1 is a perspective view from above of an end portion of a blank for forming a wraparound carton and which incorporates a box keel structure according to the invention with the keel shown in a flat collapsed condition. FIGURE 2 is a perspective view of the same end portion of the blank of Figure 1 but showing the keel in an erected condition; and FIGURE 3 is a vertical cross-section through a central part of the keel in erected condition. Referring to the drawings, an end part 10 of a blank for use in forming a wraparound type carton comprises a panel 12 for providing the base (or in some instances the top) of the carton, a box keel structure K and a securing flap 14. The blank is formed from paperboard or similar foldable sheet material and the box keel structure and securing flap are integral end portions of the blank which are returned to overlie the base panel 12. These end portions are secured in position by gluing the securing flap 14 to base panel 12. The box keel structure K comprises a first side wall panel 16 hinged along interrupted fold line 18 to the endmost edge of base panel 12, a top panel 20 and a second side wall panel 22. Top wall panel 20 is hinged to an end edge of side wall panel 16 remote from base panel 12 along interrupted fold line 24 and to the second side wall panel 22 along interrupted fold line 26. The second side wall panel is hinged to securing flap 14 along interrupted fold line 28. The fold lines 18 and 24 are interrupted by article retention openings 30, 32 struck from side wall 16 and fold lines 26 and 28 are interrupted by article retention openings 34, 36 struck form side wall 22. These retention openings are well known in the art and receive lower wall portions of articles e.g. plastic cups or pots, which are engaged by the keel structure in the carton. The keel structure is erected from its flat collapsed condition shown in Figure 1 by raising the side walls into an upright attitude whereby the structure hinges about fold lines 18, 24, 26 and 28. In order to maintain the keel structure in its erected condition cooperating locking means is provided in part by the keel and in part by the base panel and is engaged automatically as a consequence of erecting the keel structure. The cooperating locking means includes a locking tab 38 which is struck from securing flap 14 so that it is integral with and extends downwardly from a central panel 22a of side wall 22 substantially along the interrupted fold line 28. Thus, the free edge 38a of the locking tab wipes across the upward facing surface of base panel 12. The cooperating locking means further includes an upwardly projecting ridge 40 on the base panel (Figure 3) which is coextensive with the free edge 38a of the locking tab. The ridge is offset inwardly of the box keel in relation to side wall fold line 28 and when the keel is set up it is hinged overcentre so that edge 38a of the locking tab rides over the ridge and engages the side face thereof which is remote from securing tab 12. Thus, the keel is held upright against collapse in the setting up direction by the locking tab.

Claims: A carton for a plurality of articles which carton has a box keel structure (K) in which the box keel serves as an article separator and/or retention device, in which cooperating locking means (38,40) is provided in part by said keel structure (K) and in part by a panel (12) of said carton from which the keel depends, characterised in that said cooperating locking means (38,40) is automatically engaged as a consequence of erecting said keel structure (K) thereby to maintain the keel structure in an erected position within said carton in the absence of said articles. A carton according to claim 1, wherein said cooperating locking means comprises a locking tab (38) carried by said keel (K) and a raised formation (40) in a base panel (12) of said carton, said locking tab (38) and said raised formation (40) being positioned for engagement when said keel is substantially fully erected. A carton as claimed in claim 2 wherein said raised formation (40) comprises a ridge formed by indenting said base panel (12) from the face thereof remote from said keel. A carton according to claim 3 wherein a free edge (38a) of said locking tab (38) which faces downwardly when said keel (K) is erected is caused to override said ridge (40) to engage against a side surface thereof. A carton according to any of claims 2 to 4 wherein said locking tab (38) is formed at a lower edge of a side wail (22,22a) of said keel structure (K). A carton having a box keel structure according to claim 5 wherein a securing flap (14) is hinged to said side wall (22,22a), said securing flap (14) being secured in superposed relation on a base panel (12) and said locking tab (38) being struck from said securing flap (14) adjacent to the hinged connection (28) between said securing flap (14), and said side wail (22,22a). A blank for forming a carton for a plurality of articles comprising means for forming a box keel structure (K) in the carton in which the box keel serves as an article separator and/or retention device, cooperating locking means (38,40) provided in part by said keel structure means (K) and in part by a panel (12) of the blank from which the keel structure means depends, characterised in that said cooperating locking means (38,40) is automatically engaged as a consequence of erecting said keel structure (K) in said carton thereby to maintain the keel structure in an erected position within said carton in the absence of said article. A blank according to claim 7, wherein said cooperating locking means comprises a locking tab (38) carried by said keel (K) and a raised formation (40) in a base panel (12) of said blank, said locking tab (38) and said raised formation (40) being positioned for engagement when said keel is substantially fully erected, and preferably wherein said raised formation (40) comprises a ridge formed by indenting said base panel (12) from the face thereof remote from said keel, and more preferably wherein a free edge (38a) of said locking tab (38) which is adapted to face downwardly when said keel (K) is erected is also adapted to be caused to override said ridge (40) to engage against a side surface thereof during erection. A blank according to claim 8 wherein said locking tab (38) is formed at a lower edge of a side wall (22,22a) of said keel structure (K), and preferably a securing flap (14) is hinged to said side wall (22,22a), said securing flap (14) being secured in superposed relation on a base panel (12) and said locking tab (38) being struck from said securing flap (14) adjacent to the hinged connection (28) between said securing flap (14), and said side wall (22,22a). A method of forming a carton including a plurality of articles and having a box keel structure (K) in which the box keel serves as an article separator and/or retention device, in which cooperating locking means (38,40) is provided in part by said keel structure (K) and in part by a keel panel (12) in the top or bottom of said carton from which the keel depends, the method being characterised in that said cooperating locking means (38,40) are automatically engaged as a consequence of erecting said keel structure (K) thereby to maintain the keel structure in an erected position within said carton, the method comprising the step of moving the keel from a collapsed position beyond its erected position and back to its erected position thereby to effect engagement of said cooperating locking means in the absence of said articles.

Inventors: MARIE PHILIPPE, MARIE, PHILIPPE
Applicants: MEAD CORP, THE MEAD CORPORATION
Application year: 1991
Main classification: B65D71
IPC codes: B65D71, B65D5