Tub-shaped carton and blank for forming same

A generally cylindrical, tub-shaped carton having a flat bottom, and particularly suited for containing butter or margarine, is formed of a single paperboard blank, and is characterized by having a generally cylindrical-shaped side wall formed of two panels, each of which is integrally formed with and hingedly connected to one of two opposing sides of a hexagonal horizontal base portion. Intermediate each of the remaining sides of said hexagonal base portion and a side wall panel is an articulated webbed corner which, in the erected position of the carton, is wholly disposed within the tub-shaped carton in a flattened relationship against said side wall panels to reinforce the side wall seam of the tub-shaped carton. The hexagonal base or bottom of the carton is flat, thereby offering a more stable carton having greater capacity at a reduced cost of manufacture, and also offering better sealing of the carton during packaging of the butter therein.

BACKGROUND OF THE INVENTION 
The present invention relates to a new and improved carton, and more 
particularly a generally cylindrical tub-shaped carton and blank for 
making same, which is particularly suited for containing a food product, 
such as butter or margarine. The carton of the subject invention is formed 
of a single sheet of paperboard material having a new and unique 
configuration so as to result in a cylindrical container, having an 
unobstructed top portion, and a flat, reinforced rigid base portion, 
thereby greatly facilitating the loading of the carton with butter or 
margarine, and offering increased capacity, at a reduced manufacturing 
cost of the carton. In addition, when employing conventional carton 
filling equipment, the flat bottom offers improved sealing capability of 
the resulting carton even under application of a mandrel pressure during 
packaging of the food products into the carton. 
Heretofore, semi-soft food products, such as butter or margarine, have been 
packaged in paper outer wrappers, and more recently in molded plastic 
containers of generally tub-shaped configuration. Because of the molding 
operation and the cost of manufacture, it is appreciated that the cost of 
the resulting plastic container is relatively high, as compared to a 
container formed of a paper or paperboard material. It is also known to 
provide cartons of tub-shaped configuration formed of a single paperboard 
blank wherein, in order to achieve a cylindrical configuration of the 
carton from a single blank, the base of the resulting carton has included 
arcuate portions or depressions, thereby decreasing the volume of the 
resulting carton, and creating, in effect, false bottoms in the carton. 
Furthermore, with such depressions or false bottoms, the resulting base of 
such carton is not flat, and thus is less stable than desired, especially 
during filling of the carton with the food product. 
SUMMARY OF THE INVENTION 
It is an object of the subject invention to overcome the shortcomings of 
the prior art paperboard cartons, and to provide a new and improved 
tub-shaped carton having a reinforced flat bottom, and yet formed of a 
single sheet of paperboard material. In the subject invention, a 
tub-shaped carton is formed of a single sheet of paperboard material and 
basically comprises two side wall panels each of which is hingedly 
connected to one of two opposed sides of a horizontally disposed hexagonal 
base. Closure means such as an intermediate articulated webbed corner is 
integrally formed with and hingedly connected between each of the 
remaining sides of the base portion and a side wall panel, and in the 
erected condition of the carton, the articulated webbed corners are folded 
so as to be wholly disposed within the tub-shaped carton, and either in a 
position contiguous with and overlying a wall panel for reinforcing same, 
and at the same time insuring that the bottom of the tub-shaped carton is 
totally flat or, in an alternate embodiment, the webbed corner is replaced 
with a triangular panel integrally formed with and attached along the 
longest side thereof to either the bottom edge of each end of each side 
wall panel or to each of the remaining side edges of said base whereby the 
triangular panel may be positioned in a flattened condition against said 
base or in a flattened condition against said side wall panels.

DETAILED DESCRIPTION 
Referring to FIGS. 1 through 3, the tub-shaped carton of the subject 
invention is generally cylindrical in configuration and designated by the 
numeral 10. Preferably the carton is formed of a single sheet of 
paperboard material, with the blank for forming the carton being 
illustrated in FIG. 4. As shown in FIGS. 1 through 3, tub-shaped carton 10 
includes upstanding side wall 12 which is hingedly connected to a 
horizontally disposed base portion 14 that is generally flat. The side 
wall 12 is formed by two generally arcuate panels 16 and 18 which are 
connected along opposed wall seams 20 and 22, such as by bonding with 
adhesive material. As shown in FIGS. 2 and 3, the hexagonal base or bottom 
14 of the carton 10 is a flat surface. 
Referring to FIG. 4, the blank for forming carton 10 is preferably formed 
of a single sheet of paperboard material and includes first side wall 
panel 16 that has a generally arcuate top edge and a bottom edge that is 
congruent with three sides of the hexagonal base 14. The middle portion of 
said bottom edge is congruent with, hingedly attached to and integrally 
formed with base portion 14 along hinge line 38. Disposed on opposite ends 
of first side wall panel 16 are glue flaps 30 and 32 which form seams 20 
and 22, as shown in FIG. 1. The second side wall panel 18 is congruent 
with side wall panel 16 except for the glue flaps and the middle portion 
of the bottom edge thereof, is hingedly connected to and integrally formed 
with the opposite side of base portion 14 along hinge line 40. Integrally 
formed with and hingedly connected to one of the equal length sides 60 of 
the hexagonal base 14 as well as to one of the side panels 16 or 18, is 
one of four closure means which are shown as intermediate webbed corners, 
designated by the numeral 52. Each webbed corner 52 is closed by and 
includes two articulated, generally triangular segments 54 and 56 which 
are integrally formed with each other hingedly connected along line 58, 
and hingedly connected to and integrally formed with hexagonal base 48 
along hinge line 60. Segment 54 of each intermediate webbed corner 52 is, 
in turn, hingedly connected to and integrally formed with the adjacent 
first or second side panels along hinge lines 38 and 40, respectively. 
As shown in FIG. 3, during the erection of carton 10, each intermediate 
webbed corner 52 is folded about its central hinge line 58, and then about 
its associated hinge line 60 and hinge lines 38 or 40 so that each 
intermediate webbed corner is disposed wholly within the confines of the 
resulting tub-shaped carton. The partial erected position of the carton 10 
is illustrated in FIG. 3, and it is noted that intermediate webbed corners 
52 may be in a flattened condition folded against said side wall panels 16 
or 18. In the final erected condition of the carton 10, glue flaps 30 and 
32 are bonded to the opposed edges of the second side panel 18. At such 
time, the triangular-shaped segments 54 and 56 of each intermediate webbed 
corner 52 are in contiguous disposition, and folded in flattened condition 
against wall panels 16 and 18 as shown in FIG. 6. The entire bottom or 
hexagonal base 14 of the carton 10 is flat, and as such does not present a 
false bottom, thereby resulting in a more structurally stable carton 
providing greater interior volume. 
The preferred embodiment is shown in FIGS. 5 and 6 wherein the 
triangular-shaped segments 54 and 56 of each webbed corner 52 are in 
contiguous disposition and glued or otherwise attached in flattened 
condition to wall panels 16 and 18. Glue may be applied to segment 54 to 
cause it to adhere to wall panel 16 or 18. The base 14 of the tub-shaped 
carton is then totally flat for greater stability and the side wall seams 
20 and 22 are strengthened at the base thereof. 
FIG. 7 discloses the blank for forming a tub-shaped carton of a first 
alternate embodiment in which means 52 for closing each corner between a 
side wall panel 16 or 18 and one of the remaining side edges 60 of the 
base 14 is a triangular panel 54. Panel 54 is integrally formed with an 
attached along the longest side 55 thereof to the bottom edge of each end 
of each side wall panel 16 and 18. It will be understood that when the 
carton blank of FIG. 7 is folded each of said triangular panels 54 is 
folded about articulation 55 and is positioned in a flattened condition on 
said base 14. This configuration allows a flatter fold than the webbed 
corners. 
FIG. 8 discloses a blank for forming a tub-shaped carton of a second 
alternate embodiment in which means 52 for closing each corner between a 
side wall panel 16 or 18 and one of the remaining side edges 60 of the 
base 14 is also a triangular panel 56. However, unlike the embodiment of 
FIG. 7, in the embodiment, triangular panel 56 is integrally formed with 
and attached along the longest side 60 thereof to each of the remaining 
side edges of said base 14. In this case, when the carton blank is folded, 
each of said triangular panels 56 is folded about articulation 60 and is 
positioned in a flattened condition against an adjacent side wall panel 16 
or 18. This configuration allows not only a smooth base 14 but also allows 
smoother interior walls inasmuch as triangular panels 56 are only half as 
thick as the webbed corners in the preferred embodiment shown in FIG. 4. 
In contrast to the embodiment of the tub-shaped car shown in FIGS. 1, 3-6, 
the blanks shown in FIGS. 7 and 8 include a single triangular panel 54 or 
56 having the base edge thereof formed integral with the hexagonal base 14 
(FIG. 8) or the corresponding side wall panel 16 or 18, while the 
remaining two edges of such triangular panels 54 or 56 are individually 
defined by cut lines. Each of the triangular panels 54 or 56 are 
significantly shaped such that an altitude reference line extending 
perpendicular to the base edge of such panel through the vertex thereof 
defined by the intersection of the two remaining edges intersects such 
base edge at an area therealong which is spaced from the mid-point 
thereof, in a direction toward the corresponding side wall seam. Thus, for 
example, in FIG. 7, the altitude reference line 70 extends perpendicular 
to the base edge or longest side 55 and passes through the vertex 72. 
Reference line 70 intersects the base edge or longest side 55 at an area 
74 which is spaced from the mid-point 76 in a direction toward the glue 
flap 32. This feature of the invention is particularly important where 
single ply closing means 52 in the nature of a single panel 54 or 56 is 
employed because of the fact that the strength of the side wall 12 of the 
carton 10 in the radially outward direction is least at the seams 20 and 
22 defined by glue flaps 30 and 32. In other words, that portion of the 
lower edges of side wall panels 16 and 18 along hinge lines 38 and 40 is 
held in place against the hexagonal base 14 by virture of the fact that 
the base 14 is formed integral with such side wall panels 16 and 18; 
however, the magnitude of force tending to urge the opposite extremities 
of the side wall panels 16 and 18 outwardly away from the base 14 when the 
carton is in its erected condition due to the natural outward biasing of 
the material forming the side wall panels 16 and 18 increases rapidly in 
accordance with the circumstantial distance measured from the hinge lines 
38 and 40 to the seams 20 and 22. The uniquely configured triangular 
panels 54 or 56 provide, however, increased surface area to be bonded 
either to the base 14 or the side wall panels 16 and 18 in accordance with 
increased distance away from the hinge lines 38 and 40 toward the seams 20 
and 22; this increases the strength of the attachment bond between the 
base 14 and side wall panels 16 and 18 in proportion to the increased 
outwardly directed pressure imposed on the side wall panels 16 and 18 by 
the natural resiliency of the paperstock as well as by the contents within 
the carton 10. 
Accordingly, there is provided a new and improved tub-shaped carton, 
particularly suited for use in containing foodstuffs, such as butter or 
margarine, and which is formed of a single paperboard blank. The resulting 
carton has a structurally reinforced flat bottom, which is achieved by the 
new and improved structure of applicant's carton blank, which blank 
structure, when fully erected, provides the desired configuration of the 
carton, and the required strength for packaging of the foodstuffs. Since 
the blank is formed from a single blank paperboard material, the resulting 
cost of manufacture of the carton is less than heretofore achieved, 
especially compared to cartons formed of molded plastic articles. 
Furthermore, the flat hexagonal bottom of the subject carton provides a 
more stable structural carton than heretofore achieved from paperboard 
cartoons having false bottoms or depressions. 
Although the invention has been described with respect to a single 
embodiment, it is readily apparent that various modifications or 
alterations may be made in the subject carton and blank for forming same, 
without departing from the spirit and scope of the invention as defined by 
the appended claims.