Technical Field
This invention relates primarily though not exclusively to the packaging of articles which are of cube shape configuration and concerns improved means for interlocking the lap panels at the ends of a generally rectangular blank in secure overlapping relation with each other so as to form a tubular structure disposed about a plurality of articles.
Background Art
U.S. Pat. No. 4,330,079 issued May 18, 1982 discloses a wrapper in which lap panels are formed at the ends of a blank and wherein locking tabs each having a main body-portion, a heel portion and a toe portion are struck from one lap panel and wherein locking apertures are formed in the other lap panel, each locking aperture including an anchoring edge and a securing edge spaced from the anchoring edge and generally parallel thereto.
Structure such as is disclosed and claimed in U.S. Pat. No. 4,330,079 is well suited for use in packaging articles such as bottles and cans used as primary packages for consumer products and which are small in physical size and thus light in weight. This type of structure is not well suited for use in packaging primary packages which are large and heavy due to the fact that the locking tab is small and thus not very strong mechanically.
Disclosure of the Invention
According to this invention in one form, an article wrapper is provided in which lap panels are formed at the ends of the blank and in which a heel and toe type locking tab is struck from the outer lap panel and wherein an anchoring aperture is formed in the inner lap panel for receiving the heel of the locking tab during a locking operation and wherein a securing slit for receiving the toe of the locking tab is formed in general coincidence with the fold line between the inner lap panel and its associated side wall.
Brief Description of the Drawings
In the drawings,
FIG. 1 is an isometric view of an article wrapper formed according to the invention and which is shown in set-up condition but with the packaged articles removed for clarity;
FIG.2 is a plan view of a blank from which the wrapper shown in FIG. 1 is formed and
FIG. 3 includes views from below and designated A, B and C, depicting sequential stages through which the interlocking means formed according to this invention is manipulated in order to form the completed lock as shown from below in FIG. 3D.
Best Mode of Carrying Out the Invention
In the drawings the numeral 1 generally designates the main central panel of the blank and is sometimes herein referred to as the top wall of the wrapper although it will be understood that the term top wall is used in a general sense and that the wall 1 conceivably could constitute a bottom wall or even a side wall depending upon the orientation of the package. Side wall 2 is foldably joined to top wall 1 along fold line 3 while side wall 4 is foldably joined to a side edge of top wall 1 along fold line 5. Inner lap panel 6 is foldably joined to side wall 2 along the interrupted fold line by the numeral 7 while outer lap panel 8 is foldably joined to side wall 4 along fold line 9.
Locking tabs 10, 11 and 12 are struck from lap panel 8 while anchoring apertures 13, 14, and 15 are struck from lap panel 6. Securing slits 16, 17 and 18 are struck from lap panel 6 and are in general coincidence with the fold line 7 between side wall 2 and lap panel 6.
All of the locking tabs, as well as all of the anchoring apertures and securing slits are identical in configuration and in operation. Only one set of locking tabs such as 10 and the associated anchoring aperture such as 13 as well as the securing slot 16 are here described in detail. Thus with reference to FIG. 3A locking tab 10 includes a body portion 19, a heel portion 20 and toe portion 21. Body portion 19 is foldably joined to lap panel 8 along aligned fold lines 22 and 23 while toe portion 21 is foldably joined to body portion 19 along fold line 24. Arcuate slots 25 and 25a extend from the ends of fold line 24 to the edges of the locking tab as is apparent from FIG. 3A.
As is apparent from FIG. 3A anchoring aperture 13 is of generally semi-circular configuration and includes a straight line 26 and a semi-circular line 27. Line 26 is generally parallel with the end edge 28 of lap panel 6.
Slit 16 preferably is defined by a projecting portion 29 of side wall 2 which in effect is struck from lap panel 6. For some application of the invention slit 16 may be disposed astride fold line 7 and with the end slits 16a and 16b struck from side wall 2.
Views 3B and 3C depict stages through which the locking tab is manipulated as shown from below, i.e., from the bottom of the package when the package is oriented as shown in FIG. 1.
With the articles to be packaged arranged in a group to form a generally rectangular configuration, the top panel 1 is arranged in overlying relationship with the group of articles and the side walls 2 and 4 are folded downwardly. Thereafter the inner lap panel 6 is folded inwardly underneath the group of articles and the outer lap panel 8 is folded underneath the group of articles into overlapping relation with the inner lap panel 6 so that the parts then occupy the position depicted in FIG. 3B. Body portion 19 of the locking tab is swung downwardly out of the plane of lap panel 8 so as to cause the heel portion 20 to enter the anchoring aperture 13. Toe portion 21 is folded out of the plane of body portion 19 and enters the securing slit 16 as represented in FIG. 3C. During this operation, the projecting portion 29 of side wall 2 is engaged by the end portion 21a of the toe 21 and by this means the toe 21 is guided into the slit 13. It will be obvious that FIG. 3C is a view taken somewhat to one side so as to depict the lower portion of side wall 2 as well as the parts which constitute the locking mechanism.
Thereafter the body portion 19 of the locking tab is pressed toward the part of lap panel 8 which is disposed between the end edge 30 thereof and the fold lines 22 and 23 so as in effect to envelop that edge portion 30 of lap panel 8. Of course the edge portion of lap panel 8 is secured in flat face contacting relation with the lower surface of lap panel 6. The body portion 19 of locking tab 10 is then disposed in close underlying generally parallel relation with the portion of the inner lap panel 6 which is disposed between anchoring aperture 13 and securing slit 16. The completed lock then appears as shown in FIG. 3D. FIG. 3D like FIG. 3C is taken toward one side so as to depict the lower portion of side wall 2 as well as the locking element in completed locked condition. Since the securing slit 16 is spaced a substantial distance from edge 26 of anchoring aperture 13, the body portion 19 is large when compared to the corresponding parts of similar locks and is thus characterized by substantial strength and easy machineability.
Industrial Applicability
While the locks formed according to this invention are particularly well suited for use in conjunction with a wrapper used to package articles which are of cubed configuration with no voids, it is obvious that the invention is not limited to this particular use and may also apply very well to wrappers used to package articles of different configurations such as cylindrical articles for example.