Tubular carton

A tubular carton is formed from a blank of paperboard and has a side wall interconnected to a bottom wall by intermediate panels. The intermediate panels are joined to the bottom wall along convex/concave score lines.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a carton formed from paperboard or the like and, 
more particulary, to a carton having substantially cylindrical or 
substantially frustoconical configuration. 
2. The Prior Art 
Heretofore, paperboard cartons having round, oval or similarly shaped 
bottom walls were formed by folding a paperboard tube having two side wall 
forming body panels. Each panel had a disc attached to a small portion of 
its lower edge along a common fold line. 
The length of the fold line was minimized so as to have the erected carton 
as cylindrical as possible (the straight fold line obviously caused a 
distortion in the desired circular shape of the base). By minimizing the 
length of the score line, the strength and interegrity of the bottom was 
sacrificed somewhat. This was true of a conventional flush bottom or 
recessed bottom round container. 
SUMMARY OF THE INVENTION 
The carton has side wall forming panels connected to the bottom wall by 
intermediate panels. The intermediate panels are foldably joined to the 
bottom wall along convex/concave score lines. By using the convex/concave 
score lines, the length of the score line is significantly increased thus 
increasing the strength of the bottom structure of the carton. The 
convex/concave, or arcuate, score line makes it possible to have a 
completely round bottom wall, as distinguished from a cylindrical carton 
with flat facets. Further, the present concept provides a possibility of 
constructing a liquid tight bottom by carrying the opposed arcuate score 
lines to a meeting point. 
The basic concept is readily adaptable to flush bottom wall or recessed 
bottom wall variations, and the arcuate line can be easily changed to an 
eliptical curve or rounded corner polygonal shapes without sacrificing 
structural integrity.

Referring now to the drawings, more specifically to FIGS. 1 through 3, 
there is shown a first embodiment of the present invention comprising a 
blank, generally designated 10, and a carton, generally designated 11, 
formed from the blank 10. 
The blank 10 has a pair of body panels 12 and 14 foldably connected to each 
other along a score line 18. The body panels form a side wall of the 
carton, as later described. The outer vertical side edges of the body 
panels 12 and 14 are provided with attaching panels 20 and 22, 
respectively. The panel 20 is foldably attached to the body panel 12 along 
a fold line 24, while the panel 22 is foldably attached to the body panel 
14 along a fold line 26. Since it is desired to form a tubular, 
substantially cylindrical carton having tapered side wall, fold lines 24 
and 26 converge slightly toward one another in the downward direction 
between top and bottom edges of the body panels, as viewed in FIG. 1. In 
view of the taper in the side wall, fold lines 24 and 26 are not parrallel 
to the score line 18 mentioned above. 
As best seen in FIG. 1, there are two bottom wall forming panel portions 28 
and 30. The panel portion 28 has an attaching flap 32 foldably joined to 
the outer edge thereof along a fold line 34. 
The panel portion 28 is connected to the side wall forming body panel 12 by 
an intermediate panel 36, whereas the panel portion 30 is connected to the 
body panel 14 by an intermediate panel 38. 
The intermediate panels 36 and 38 are foldably joined to their respective 
body panels 12 and 14 along substantilally straight fold lines 40 and 42, 
respectively. The intermediate panels 36 and 38 are foldably attached to 
the bottom wall forming panel portions 28 and 30 by convex/concave score 
lines 44 and 46, respectively. The interior tapered edges of the 
intermediate panels 36 and 38 are spaced from each other as indicated at 
48. 
In forming the caron 11 from the blank 10, glue panels 20 and 22 are 
secured to each other in an overlapped relation forming a tapered tubular 
structure, as best seen in FIG. 2. The glue panel could overlap a marginal 
area of the body panel and could be secured thereto. Likewise, glue panels 
could be eliminated and the marginal areas of the body panels could be 
secured to one another in an overlapped relation. 
The intermediate panels 36 and 38 are folded in such a manner as to provide 
a recessed and curved bottom wall formed from overlapped bottom panel 
portions 28 and 30 which are secured to one another. The carton so 
constructed can be collapsed into flat position and re-erected again by 
inward pressure on the side wall of the carton from two opposite sides. 
Referring now to FIGS. 4 thru 6, there is shown a second embodiment of the 
present invention. Like elements have been designated with the same 
numerals used to designate the elements in the description of the first 
embodiment except that 100 has been added to each numeral to describe the 
elements of the second embodiment. 
The second embodiment comprises a blank, generally designated 110 and a 
carton, generally designated 111 formed from said blank. The blank 110 has 
three body panels 112, 114 and 116 foldably connected by score lines 118 
and 119. In this exemplary embodiment, the three body panels are of 
different sizes. The areas along remote side edges of the panels 112 and 
116 are secured to one another in overlapped fashion when the carton is 
constructed and thus perform a function similar to the one performed by 
the glue panels 20 and 22 of the first embodiment. The blank shown in FIG. 
4 has a top edge flap 21 foldably connected to the body panels along fold 
line 123. As best seen in FIG. 5 the top edge flap is folded inwardly into 
the carton and is formed with a plurality of apertures 125 adapted to 
receive and securely hold a cover (not shown). 
There are three bottom wall forming panel portions of differing sizes and 
shapes. A panel portion 128 has an attaching flap 132 foldably joined 
thereto along a fold line 134. Flap portions 131 and 133, when joined to 
each other, generally represent a structure similar to the panel portion 
30 illustrated in FIG. 1. 
There are three intermediate panels in this embodiment. Intermediate panel 
136 joines the panel portion 128 to the body panel 114 and has a 
substantially straight fold line 140 joining it to the body panel 114 and 
a convex/concave fold line 114 joining it to the panel portion 128. The 
remaining intermediate panels 137 and 139 are attached to the respective 
body panels 112 and 116 along straight fold lines 141 and 143, 
respectively. A curved fold line 145 joins panel portion 131 to the 
intermediate panel 137, while a curved fold line 147 performs a similar 
function between the panel portion 133 and the intermediate panel 139. The 
inner edges of intermediate panels are spaced from each other as indicated 
at 148. 
The carton is constructed in a manner similar to that used in constructing 
carton 11 of the first embodiment. In the present embodiment, the body 
panels 112 and 116 have their remote side edge area secured in an 
overlapped relation. A recessed and curved or concavely depressed bottom 
wall is formed from three panel portions, namely 128, 131 and 133. As 
mentioned before, the carton of this embodiment is provided with an 
inwardly folded top edge flap 121 and presents a straight sided rather 
than tapered configuration with a substantially circular cross section. 
The third embodiment of the present invention is illustrated in FIGS. 7 
through 9. Here, again, like elements have been designated with the same 
numerals used heretofore except that 200 has been added to each numeral. 
A blank 210 of this embodiment is generally similar to the blank 110 of 
FIG. 4 and is used to form a carton 211 having straight, rather than 
tapered, side wall. There are three body panels of varying size identified 
by numerals 212, 214 and 216. Score lines 218 and 219 foldably connect the 
adjacent body panels to each other. 
The bottom wall of the carton 211 is formed from a panel portion 228 of 
generally eliptical configuration which is divided into two segments by a 
fold line 235. The panel portions 231 and 233 overlap the portion 228 and 
are secured thereto by any suitable means well known in the art. As best 
seen in FIG. 8, the bottom wall is not flat but has a curved 
configuration. 
An intermediate panel 237 interconnects the panel portion 231 with the body 
panel 212 so that the panel portion 231 can be folded on the curved score 
line 245 while the intermidiate panel 237 can be folded against the body 
panel 212 along a substantially straight score line 241. 
Similarly, an intermediate panel 236 is foldably joined to the body panel 
214 along a substantially straight score line 240 and to the bottom wall 
forming portion 228 along a convex/concave, or curved, score line 244. An 
intermediate panel 239 is foldably joined to the body panel 216 along a 
line 243 while being foldably attached to the panel portion 233 along a 
curved score line 247. The intermediate panels are spaced from each other 
as shown at 248. 
In forming the tubular configuration the marginal areas along the remote 
edges of the body panels 212 and 216 are secured in an overlapped 
relation. 
Once the carton is formed, it can be collapsed by folding its bottom wall 
along the line 235 and its side wall along the lines 218 and 219. As 
described in connection with prior embodiments, the carton can be brought 
out of collapsed position by pressure applied against opposite edges of 
the bottom wall at the ends of the line 235. 
The fourth embodiment of the present invention is shown in FIGS. 10 through 
13 with like elements designated with the same numerals as before except 
that 300 has been added to each numerals. 
A blank 310 is used to form a tubular carton 311 of substantially oval 
cross-section. 
A side wall is formed from body panels 312 and 314 foldably connected along 
a score line 318. A panel 322 which is an extension of panel 314 is 
secured to the outer surface of panel 312. 
The bottom wall is concavely depressed, or dished-out and is formed from 
two panel portions 328 and 330 in an overlapped manner and secured by an 
attaching flap 332 foldably joined to the portion 328 by a line 334. 
Generally straight fold lines 340 and 342 secure an intermediate panel 336 
to the body panel 312 and an intermediate panel 338 to the body panel 314, 
respectively. 
Convex/concave lines 344 and 346 foldably attach the intermediate panels 
336 and 338 to the panel portions 328 and 330, respectively. 
The inner edges of the intermediate panels 336 and 338 are spaced from each 
other as indicated at 348. 
The carton 311 is collapsible along lines 318, 326 and 334 and can be 
re-erected as described heretofore in regard to other embodiments of this 
invention.