FOR CORRUGATED CONTAINERS

AND BLANK THEREFOR

BACKGROUND OF THE INVENTION

This invention relates to the manufacture of corrugated containers and, more particularly, to a process of self- centering a corrugated liner member onto a container blank and a blank for use in such a process.

In the construction of corrugated containers, it is common to place or glue a liner member on the inner surface of a box blank to form a laminated structure. Usually, the fluting of the liner is transverse to the fluting of the blank to increase the rigidity of the assembled product.

During the blank folding process, the liner may become misaligned if it has not been precisely centered in its correct position on the blank. Such misalignment can comprise a portion of the liner overlying one or more of the fold lines on the blank. Usually, the placement of the liner member onto the blank is done by hand to attempt to insure the correct placement of the liner. Therefore, a process has been needed to eliminate the labor-intensive step of precisely situating the liner on the blank.

SUMMARY OF THE INVENTION

The above disadvantages are overcome by the present invention which comprises a self-centering laminated process for corrugated containers and the blank therefor. A corrugated container blank is provided with a pair of parallel, longitudinally extending first and second fold lines along its inner surface. Each of the second fold lines is adjacent the outer side edge of the blank, with an outer edge panel being defined between each second fold line and each of the respective outer side edges of the blank.

The distance between each first and second fold line approximates the thickness of the liner and the distance between the inner, first fold lines defines a central portion on the blank which is the width of the inner liner member.

The laminating process is as follows: glue is applied to the inner surface of the blank and the liner member is then generally positioned on the central portion of the blank. Alternatively, glue may first be applied to the underside of the liner which is then positioned onto the blank; glue is then applied to the inner surfaces of the outer edge panels.

The outer edge panels are then simultaneously folded upwardly 90° about the first fold lines which automatically aligns the liner member on the blank so that the sides of the liner are in alignment with the first fold lines. The outer edge panels are then folded inwardly another 90° about the fold lines so that the outer edge panels now overly the liner. The laminated assembly can then be fed to a pressure roll conveyor to complete the bonding process.

The folding of the outer edge panels upon the top of the liner member not only centers the liner onto its desired position overlying the central portion of the blank, but also provides a cosmetically appealing appearance to the erected container by covering the fluting of the exposed sides of the liner.

BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWINGS

Fig. 1 is a schematic view of the steps of the self- centering lamination process of the present invention; and Figs. 2A - 2C are end views of the outer edge panels of the container blank being folded onto the liner member;

Fig. 3 is a schematic view of an alternate embodiment of the present invention;

Figs. 4A and 4B are end views of glue having been applied to the outer edge panels which are folded onto the liner member; and

Fig. 4C is an end view of an erected container utilizing the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the figures of the drawing, the numeral 10 refers to the finished laminated assembly of the corrugated container blank 12 and the corrugated inner liner 14. The blank 12 can be for any type of container or box which requires an inner liner 14 for strengthening purposes. The blank 12 will probably include additional elements such as other fold lines and cut lines, as depicted in Fig. 3. Thus, the blank 12 is meant to represent only the relevant portion of an otherwise conventional blank for corrugated containers.

As shown, the blank 12 is one-piece and has inner and outer surfaces 16, 18 and front and side edges 20, 22. A pair of longitudinally extending, parallel first fold lines 24 are formed on the inner surface 16. The first fold lines 24 border a rectangular central portion 26. Spaced from the first fold lines 24 is a second fold line 28, thereby forming intermediate panel 30 therebetween. An outer edge panel 32 on the blank 12 is defined between the second fold line 28 and the side edge 22. The length of the panels 32 and the fold lines 24, 28 is approximately equal to the length of the liner member 14.

The liner member 14 is rectangular in shape, having top and bottom surfaces 34, 36 and end and side walls 38, 40. The width of the liner 14 between its side walls 40 is the same as the width of the central portion 26 (i.e. , the distance between the first fold lines 24) . The height of the liner 14 from its top and bottom surfaces 34, 36 is equal to the width of the intermediate panel 30 (i.e.. the

distance between the first and second fold lines) . Usually, the fluting of the blank 12 and the liner 14 is transverse to the other in order to provide extra strength to the finished container.

The first embodiment of the lamination process is shown in Fig. 1 and is as follows: glue is applied to the inner surface 16 of the blank 12 at a gluing station A by conventional means, such as a glue roll 42. The blank 12 is then moved to station B where it receives the liner 14 which is usually fed transversely to the path of travel of the blank 12. Either manually or mechanically, the bottom surface 36 of the liner 14 is placed onto the blank 12 to generally overly the central portion 26.

Care has to normally be taken so that the side walls 40 of the liner 14 are in registration with the sides of the central portion 26 defined by the first fold lines 24. Fig. 2A illustrates a misalignment of the liner 14 on the blank 12 with the distance marked "misalignment" being the space between the side walls 40 and the first fold line 24. Thus, fold lines (not shown) in the liner 14 would not be in registration with respective fold lines (also not shown) on the blank 12, resulting in uneven folding with a possible buckling in the finished product of the liner 14 on the blank 12.

The fold lines 24, 28 and the outer edge panels 32 provide an automatic means for centering the liner 14 onto the blank 12. As seen in Figs. 1 and 2B, the outer edge panels 32 are first bent upwardly 90° about first fold line 24 at the folding station C. During that process, any misalignment of the liner 14 in its position on blank 12 is automatically corrected. Thus, the misalignment in Fig. 2A is corrected by having the liner 14 be shifted to the right in the figure the distance of the misalignment with the liner 14 now captured between the upright outer edge panels 32. Also, while at the folding station C, the

panels 32 are then folded downwardly 90° about the second fold lines 28 so that the inner surfaces of the panels 32 overlap a portion of the top surface 34 of the liner 14.

Referring again to Fig. 1, the laminated assembly 10 is then moved to station D where the assembly 10 is fed between opposed pressure rolls 44 for a predetermined glue cure time at a predetermined pressure to cement the liner 14 onto the blank 12. From station D, the assembly 10 can be moved to subsequent conventional container-erecting stations which may result in a container as shown in Fig. 4C.

Figs. 3 and 4A and 4B depict another embodiment of the carton-forming process. The liner 114 is fed between an upper feed roller 46 and a lower glue roller 48 whereby glue 50 is applied to the bottom surface 136 of the liner 114. The liner 114 is then placed generally onto the central portion 126 of the blank 120 and glue 50 is applied to the outer edge panels 132. The panels 132 are then folded about fold lines 124, 128 onto the liner 114, as described above for the first embodiment. The assembly is then indexed into the compression section, as described above, to form the laminated product.