IE43096B1 - Interlocking - Google Patents

Description

This invention relates generally to the packaging arts, and more cifically to interlocking of a pair of panels together in overlapping relation, and o to novel article carrier cartons and blanks therefor including a pair of panels pted to be so interlocked.

Panel interlocking means which comprise a so-called heel and toe angement inserted into a locking aperture thereby interconnecting two panels known. Historically this type of panel interlocking means has been utilized ι top closures for light duty carriers requiring very little strength in the i of the lock. In addition this type of interlocking means has been utilized in :alled wraparound article carriers which do not require end closure means. In ir to form this known type of locking arrangement, a portion of the toe must be led in a transverse direction in order to insert it into the corresponding ture. This procedure tends to weaken the lock thereby making it very sirable for packages requiring strength between the locked panels. Such ication of a heel and toe type lock is feasible only because the packaged cles are disposed in firm engagement with the toe and heel and thus prevent vertent release of the lock. Where strength is required and where the aged items do not aid in holding the lock in locked condition, known heel and locks are not satisfactory. - 2 43096 According to a first aspect of this invention, we provide interlocking means for securing two panels together in overlapping relation, said interlocking means comprising a locking tab joined to one of the panels along a fold line and having an integral locking toe and an integral locking heel extending in opposite directions and generally transverse to said fold line, and a locking aperture formed in the other panel and having a locking edge for engaging said locking heel upon insertion of said locking heel into said locking aperture in co-ordination with folding of said locking tab along said fold line out of the plane of said one panel and relative movement of the panels toward each other, said locking toe being of a size and configuration different from said aperture such that locking swinging movement of said locking tab causes edge portions of said locking toe other than its medial extremity to overlap corresponding parts of said other panel while simultaneously allowing the extremity of said locking toe to clear the corresponding part of the edge of said locking aperture thereby to fold said locking tab along a longitudinal fold line during a locking operation without substantial transverse bending of said locking tab.

In a second and alternative aspect of this invention, we provide a pair of panels adapted to be secured together in overlapping relation, one said panel being provided with a locking tab joined to the remainder of said panel along a fold line and having an integral locking toe and an integral locking heel extending in opposite directions and generally transverse to said fold line; and the other of said panels being provided with a locking aperture into which the locking heel and locking toe are adapted to be inserted; the locking toe being of a size and configuration which is sufficiently different from the corresponding configuration of the locking aperture both to allow an amount of overlap when said panels are interlocked and to allow the extremity of said locking toe to clear the corresponding part of the edge of said locking aperture when said locking toe is inserted therein with said locking tab folded along a longitudinal fold line and without substantial transverse bending of said locking tab. - 3 0 8 6 The invention provides, in a third alternative aspect thereof, an article carrier carton having top lap panels, and bottom and side walls interconnected to form a tubular structure and provided with end closure means in the form of end panels hinged to each end edge of each side wall, the end panels being folded into overlapping relationship and being secured together by interlocking means which comprises at least one locking aperture formed in one end panel at each end of the carrier and arranged to co-operate with a corresponding locking tab which is foldably joined to the other end panel at each end of the carrier and has an integral locking toe and an. integral locking heel extending in opposite directions, the locking heel and locking toe being arranged to be inserted into the locking aperture, and the locking toe being of a size and configuration different from that of the locking aperture to allow the medial extremity of the locking toe to clear the corresponding part of the locking aperture edge while other portions of the locking tab overlap corresponding portions of the said one end panel, whereby the locking tab is caused to fold along a longitudinal fold line during a locking operation.

Me provide, according to a fourth alternative aspect of this invention, a method for interlocking a pair of panels in overlapping relation, which method comprises the steps of: folding a locking tab associated with one of the said panels out of the plane of said panel about a fold line along which said locking tab is joined to the remainder of its said panel, the locking tab having an integral locking toe and an integral locking heel extending in opposite directions and generally transverse to said fold line; inserting said locking heel into a co-operating locking aperture formed in the other of said two panels; thereafter folding said locking tab in the opposite direction about its said fold line and at the same time causing it to fold along a longitudinal fold line, such that said locking toe is enabled to clear the corresponding part of the edge of the locking iperture and to be inserted through the said aperture; and thereafter allowing ;aid locking tab to relax. - 4 4309 6 The invention is hereinafter more particularly described with reference to the accompanying drawings, in which:FIG. 1 is a perspective view of an article carrier having an embodiment of end panel closure means formed according to this invention; FIG. 2 is a plan view of a blank from which the carrier shown in FIG. 1 is formed with portions thereof removed; FIG. 3 depicts a completed carrier in collapsed condition with portions thereof removed; FIG. 4 is an enlarged cross-sectional view depicting an intermediate stage in the forming of a closure with an embodiment of panel interlocking means according to this invention; FIG. 5 is a view of an embodiment of panel interlocking means formed according to this invention; FIG. 6 is a cross-sectional view of a panel interlocking means taken along line 6-6 in FIG. 5; and FIG. 7 depicts another embodiment of panel interlocking means also according to this invention.

In the- drawings the numeral 1 designates the bottom wall of the carrier. Side wall 2 is foldably joined to bottom wall 1 along fold line 3 and side wall 4 is foldably joined to bottom wall 1 along fold line 5. End wall panels 6 and 7 are respectively joined to side wall 2 along fold lines 8 and 9. Similarly, end wall panels 10 and 11 are foldably joined respectively to side wall 4 along fold lines 12 and 13. End closure flaps 14 and 15 are respectively joined to bottom wall 1 along fold lines 16 and 17. Top lap panel 18 is foldably joined to side wall 2 along fold line 19 and top lap panel 20 is foldably joined to side wall 4 along fold line 21. End closure flaps 22 and 23 are respectively joined to top lap panel 18 along fold lines 24 and 25. In like manner end closure flaps 26 and 27 are respectively joined to top lap panel 20 along fold lines 28 and 29. Hand carrying apertures 30 and 31 are respectively formed in top lap panels 18 and 20. - 5 auae Locking tabs 32 and 33 are foldably joined to end wall panel 6 along fold line 34 and, likewise, locking tabs 35 and 36 are foldably joined to end wall panel 7 along fold line 37. Also locking apertures 38 and 39 are formed in end wall panel 10 and respectively include locking edges 40 and 41, Likewise locking apertures 42 and 43 are formed in end wall panel 11 and are provided with locking edges 44 and 45 respectively. Each locking tab is provided with a locking toe as indicated by the letter T. In addition each locking tab is provided with a locking heel as indicated by the letter H.

As shown in the drawings, a longitudinal score line designated L is incorporated into the locking tabs. While this score line is desirable for many applications, the invention is not limited thereto and for certain applications it may be omitted.

In order to form the carrier blank as shown in FIG. 2 ihto the collapsed condition as shown in FIG. 3, it is simply necessary to first fold top lap panel 20 upwardly and to the right along fold line 21. Thereafter an application of glue is applied to top lap panel 18 as indicated by stippling in FIG. 2. Finally the portion of the carrier blank to the right of fold line 3 is elevated and folded to the left into the position depicted in FIG. 3.· This operation secures the top lap panels together so that loading may be effected through the ends after the carrier is manipulated into set up open ended condition.

In order to form the completed article carrier appropriate for the reception of primary packages, the collapsed carrier, as shown in FIG. 3, is opened by forming machinery and assumes a generally rectangular shape with both ends of the carrier in the open position. In order to close the ends of the carrier, end closure flaps 14, 15, 22, 23, 26 and 27 are folded inwardly into a position perpendicular to bottom panel 1 and top lap panels 18 and 20. Then end wall panels 10 and 11 are folded into a position perpendicular to side walls 2 and 4. As shown in FIG. 4 end wall panels 6 and 7 are then folded downwardly while at the same time locking tabs 32 and 33 are folded upwardly along fold line 34 - 6 43096 and likewise locking tabs 35 and 36 are folded upwardly along fold line 37. Subsequently the locking heel H of each locking tab 32, 33, 35 and 36 is swung into abutting overlapping engagement with corresponding, locking edges 40, 41, and 45 as the locking heels are inserted into the locking aperture.

Thereafter an appropriate machine element pushes locking toe T of each locking tab into the corresponding locking aperture and into overlapping engagement with a portion of the locking aperture as shown in FIG. 5.

Conventional heel and toe type locking arrangements for interconnecting two panels are ordinarily formed by first folding a locking tab out of the plane ig of the panel to which it is foldably joined and subsequently by inserting the heel portion of the locking tab into a locking aperture formed in the other panel. Following this operation and in accordance with the prior art, the locking toe is folded toward the locking aperture and is simultaneously folded along a transverse fold line which enables the locking toe to enter the locking aperture. After the lock is completed, the locking toe is folded back into the plane of the locking tab and, when thus formed, is susceptible to release if any significant stress is applied because the locking toe is already conditioned to bend along the transverse fold line thereby to release the lock.

In our arrangement described herein the locking toe is constructed and 2q manipulated in such a way that transverse folding and the resulting weakening of the locking tab is prevented. Instead, the locking toe is forced to bend along a longitudinal rather than a transverse fold line and such bending does not tend to weaken the lock. In order to ensure bending along a longitudinal fold line, the size and configuration of the locking tab relative to the locking aperture is such that clearance space is provided at the medial extremity of the locking tab which allows the medial extremity of the locking tab to swing into locked condition without engaging the medial part of the end edge of the locking aperture. A notch in the medial extremity of the tab may contribute to this clearance, as may a notch on the corresponding part of the edge of the aperture. Folding of the locking toe along a longitudinal fold line is effected by a machine element which engages - 7 003 the locking toe along a longitudinal generally medial portion to force the locking toe through the locking aperture. Furthermore the locking toe is wider than the corresponding dimension of the locking aperture at the outer end thereof so that prior and subsequent to locking the locking toe overlaps certain edge portions of the locking aperture on the outside of the panel 11 and subsequently on the inside thereof. Thus during formation of the lock the locking machine element forces the locking toe to bend along a longitudinal fold line and upon completion of the lock allows the side edges of the locking toe to spring back into face contacting engagement with the adjacent corresponding edge portions of the locking-aperture. Thus the lock is formed and secured in locked condition without weakening the locking tab in a direction which facilitates unlocking.

Therefore a heel and toe type lock is provided which is capable of withstanding substantial stress.

From FIG. 5 it is clear that the outer truncated corners of the locking tab designated at C overlie the adjacent portions of the locking aperture.

Furthermore from FIG. 5 it is apparent that the clearance notch N, which forms a portion of the edge of the locking aperture, establishes a clearance distance at the outer end of the score line L so that when the locking tab is forced through the locking aperture to occupy the locked condition, end edge portions of the locking aperture offer no resistance whereas the corner portions C of the locking tab must be forced through the locking aperture. In order to effect a lock, the locking tab must fold longitudinally thereof along the score line L, if such a score line is used. If the score line L is not Used, the function is the same.

Since the locking tab is precluded from bending along a weakening transverse fold line, it is possible that the side edges E of the locking apertures might interfere with the formation of the lock and conceivably might damage the corresponding edges of the locking toe. It may be desirable for certain applications to form the locking apertures in such a manner that they are rendered somewhat yieldable. This may be accomplished by forming at least one slit S which extends laterally from the locking aperture (two are shown here) and in such - 8 43086 manner that its inner end coincides with the side edge of the locking aperture.

While slits S for many applications are desirable, it is not necessary to use the slits S for applications where the transverse dimension of the aperture is significantly greater than the corresponding dimension of the associated locking toe.

FIG. 7 depicts a modification which provides a clearance notch 'N1 in the locking tab while at the same time eliminating the need for a clearance notch in the locking aperture. The arrangement of FIG. 7 like that of FIGS. 1-6 simply provides unobstructed clearance for the medial end portion of the locking toe while providing a locking toe and aperture configuration which force medial bending of the locking tab during a locking operation along a longitudinal line of bend and thereby prevent bending along a transverse line and the resultant weakening of the lock. In other arrangements both the aperture edge and the tab extremity may be formed with a notch.

By the specifically described arrangements panel interlocking means are provided which allow the packaging of very large primary packages by utilizing strong locks while at the same time providing article carriers of attractive appearance.

Claims (24)

1. Interlocking means for securing two panels together in overlapping relation, said interlocking means comprising a locking tab joined to one of the panels along a fold line and having an integral locking toe and an integral locking heel extending in opposite directions and generally transverse to said fold line, and a locking aperture formed in the other panel and having a locking edge for engaging said locking heel upon insertion of said locking heel into said locking aperture in co-ordination with folding of said locking tab along said fold line out of the plane of said one panel and relative movement of the panels toward each other, said locking toe being of a size and configuration different from said aperture such that locking swinging movement of said locking tab causes edge portions of said locking toe other than its medial extremity to overlap corresponding parts - 9 3088 of said other panel while simultaneously allowing the extremity of said locking toe to clear the corresponding part of the edge of said locking aperture thereby to fold said locking tab along a longitudinal fold line during a locking operation without substantial transverse bending of said locking tab.

2. Interlocking means according to Claim 1, wherein a score line extends generally medially of said locking tab,

3. Interlocking means according to Claims 1 or 2, wherein a clearance notch is disposed along the edge of the locking aperture at a position remote from said locking edge.

4. Interlocking means according to Claim 3, wherein said edge remote from said locking edge is of an arcuate configuration.

5. Interlocking means according to any preceding claim, wherein a clearance notch is disposed along the end edge of said locking toe remote from said locking heel.

6. Interlocking means according to any preceding claim, wherein at least one slit is disposed in said other panel with one end thereof in coincidence with a side edge of said locking aperture.

7. Interlocking means according to Claim 1, wherein at least one slit is disposed in said other panel with one end thereof in coincidence with a side edge of the locking aperture and a score line extends generally medially of said locking tab and defines the longitudinal fold line along which the tab folds during a locking operation.

8. Interlocking means according to any preceding claim, wherein said locking toe is of generally rectangular configuration having truncated end corners.

9. Interlocking means for securing two panels together in overlapping relation, said interlocking means being substantially as hereinbefore described vi th reference to and as shown in the accompanying drawings.

10. A pair of panels adapted to be secured together in overlapping relation ;y interlocking means constructed according to any preceding claim. - 10 43096

11. A pair of panels adapted to be secured together in overlapping relation, one said panel being provided with a locking tab joined to the remainder of said panel along a fold line and having an integral locking toe and an integral locking heel extending in opposite directions and generally transverse to said , fold line; and the other of said panels being provided with a locking aperture into which the locking heel and locking toe are adapted to be inserted; the locking toe being of a size and configuration which is sufficiently different from the corresponding configuration of the locking aperture both to allow an amount of overlap when said panels are interlocked and to allow the extremity of said locking toe to clear the corresponding part of the edge of said locking aperture when said locking toe is inserted therein with said locking tab folded along a longitudinal fold line and without substantial transverse bending of said locking tab.

12. An article carrier carton provided with a plurality of panels including two panels according to Claim 10 or Claim 11 adapted to be secured together.

13. An article carrier carton having top lap panels, and bottom and side walls interconnected to form a tubular structure and provided with end closure means in the form of end panels hinged to each end edge of each side wall, the end panels being folded into overlapping relationship and being secured together by interlocking means which comprises at least one locking aperture formed in one end panel at each end of the carrier and arranged to co-operate with a corresponding locking tab which is foldably joined to the other end panel at each end of the carrier and has an integral locking toe and an integral locking heel extending in opposite directions, the locking heel and locking toe being arranged to be inserted into the locking aperture, and the locking toe being of a size and configuration different from that of the locking aperture to allow the medial extremity of the locking toe to clear the corresponding part of the locking aperture edge while the other portions of the locking tab overlap corresponding portions of the said one end panel, whereby the locking tab is caused to fold - 11 3096 along a longitudinal fold line during a locking operation.

14. An article carrier carton according to Claim 13, wherein a score line extends generally medially of said locking tab.

15. An article carrier carton according to Claims 13 or 14., wherein a clearance notch is disposed along the edge of the locking aperture at a position remote from said locking edge.

16. An article carrier carton according to Claim 15, wherein said edge remote from said locking edge is of an arcuate configuration.

17. An article carrier carton according to any of Claims 13 to 16, wherein a clearance notch is disposed along the ehd edge of said locking toe remote from said locking heel.

18. An article carrier carton according to any of Claims 13 to 17, wherein at least one slit is disposed in said other panel with one end thereof in coincidence with a side edge of said locking aperture.

19. An article carrier carton according to Claim 13, wherein at least one slit is disposed in said other panel with one end thereof iri coincidence with a side edge of the locking aperture and a score line extends generally medially of said locking tab and defines the longitudinal fold line along which the tab folds during a locking operation.

20. An article carrier carton according to any of Claims 13 to 19, wherein said locking toe is of generally rectangular configuration having truncated end corners.

21. An article carrier carton substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

22. A carton blank for an article carrier carton according to any one of Claims 12 to 21.

23. A method for interlocking a pair of panels in overlapping relation, which a locking method comprises the steps of: folding/tab associated with one of said panels out of the plane of said panel about a fold line along which said locking tab is joined to the remainder of its said panel, the locking tab having an integral locking toe and an integral locking heel extending in opposite directions and generally - 12 43096 transverse to said fold line; inserting said locking heel into a co-operating locking aperture formed in the other of said two panels; thereafter folding said locking tab in the opposite direction about its said fold line and at the same time causing it to fold along a.longitudinal’ fold line, such that said 5 locking toe is enabled to clear the corresponding part of the edge of the locking aperture and to be inserted through the said aperture; and thereafter allowing said locking tab to relax.

24. A method for interlocking a pair of panels in overlapping relation, as claimed in Claim 23 and. / substantially as hereinbefore described.