Note: Descriptions are shown in the official language in which they were submitted.
FLEXIBLE BOTTOM PROFILE FOR
DRAWN AND IRONED BEVERAGE CAN
This invention relates to a can with a dome-shaped
(calotte) bottom outwardly or inwardly offset center portion
circumscribed by an annular bead between the dome and the can
body.
Cans in one piece of a similar kind are known as
disclosed in U.S. patents 3,369,694, 3,904,069 and 3,409,167
which show various types of expandable bottoms. The disad-
vantages or problems in these known cans are that:
a. The application of the profiles disclosed leadto a considerable difference in height between the closed and
the empty can, on the one hand, and the conventional can with
a large rigid calotte (cup) on the other. This has as a con-
sequence costly conveyor changes in the installations at thecustomer.
b. Furthermore, in the conventional can with the
large, rigid calotte, it is known that the adhesion of lac-
quer or coating on the interior is worse where the slightest
deformation of the sheet metal takes place, namely in the
area of the bottom profile. Such profiles as dlsclosed in
the above references are submitted to a lesser deformation
than that of the instant invention.
c. When the containers with the prior art profiles
are pressurized rolling out of the ends which delimits the
small calotte from the flat portion can occur. The thereby
caused embrittlement of the lacquer may cause a premature
defect of the can.
d. The relative afterflow of the sheet material
from the body into the area of the bottom is greater in the
disclosed profiles than in case of the conventional large
rigid calotte.
e. The resulting value of the unit pressure upon
the small calotte is smaller in case of the known profile
than the pressure upon the conventional calotte, but thç
sheet metal in the area of the smaller inner calotte is un-
necessarily thick.
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These problems are solved by the features of the
preserlt invention. In case of cold~drawn cans it is caused
by deformations in the annular bottom area that in stretch-
drawing and in forming the bottom deformations less of the
material flows from the body area into the bottom area and
the calotte-shaped section is equally stretch-drawn by a
reduction of the thickness of its sheet metal, while in the
known cans only a deformation of the area of the calotte is
basically obtained. By the greater stretching of the area
of the calotte, a considerably better adhesion of the lacquer
layers on the inner surface of the can is obtained in the
bottom area because of the greater roughness caused by the
stretching operation and the larger area thereof.
A to-the-outside circular, or even better an in-
ward projecting bead in the bottom section has proven to beadvantageous. This bead borders advantageously directly with
the edge of the calotte. The bead needs to project only
qlightly from the plane, in which the outer edge of the an-
nular bottom section is placed, to the outside or to the in-
side. ~ height of the bead of less than 2 mm, preferably aheight between 0.2 and 0.5 mm suffices. In the latter case,
the stability of the empty can above all is also improved.
In a crown-shaped arrangement of several deforma-
tions in the annular bottom section these deformations pro-
ject throughout into the inside of the body of the can. Thedeformations can then penetrate at least into the inner
delimiting edge of the annular bottom section, so that they
penetrate slightly even into the calotte area.
This invention relates to the provision of a metal
can for pressurized packaged products, the can in an as formed
non-pressurized state comprising a cylindrical body and an in-
tegral bottom, the bottom including an outer transition sec-
tion of inverted frustoconical shape joined to the body by a
radius, a generally planar intermediate ring-shaped section,
and a central calotte-shaped section pro3ecting into the in-
terior of the can, the can bottom being characterized by stif-
fening deformation means in the intermediate ring-shaped section.
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It has also proven to be of further advantage to
provide several blank (cup) like impressions dividedly ar-
ranged in the annular bottom section on two concentric par-
tial circles.
The invention is best explained on several ex-
amples of embodiments with the aid of schematic drawings
wherein:
Figure 1 is a vertical sectional view of the
lower portion of a can made according to the invention;
Figure 2 is a fragmentary bottom view of the can
shown in Figure l;
Figures 3, 5, 6, 7, 8, 10, 12, 14 and 16 are
fragmentary schematic vertical sectional views of various
embodiments of the invention, and Figures 4, 9, 11, 13, 15,
and 17 are fragmentary bottom views of the cans of Figures
3, 8, 10, 12, 14 and 16, respectively.
The can shown in Figures 1 and 2 has a basically
cylindrical can body 1 which at its lower end is integral -
with a bottom. The transition between the body and the
bottom can be made by a rounding or curve, preferably, how-
ever, by a beveling in the shape of a truncated cone 3, as
shown in Figure 1. The bottom proper consists of two sec-
tions, namely of a central section 6 projecting into the `
inside of the body 1 and being of ~alotte or dome shape, and
surrounding the central section 6 is an intermediate bottom
section 5 that is basically radially extending. The radial
W~dth of the annular section 5 of the bottom 2 is radially
li~ited ~t the in$ide by the edge 8 to the calotte shaped
portion 6 and at the outside by ~he edge 4 of the transition-
al sec~ion 3, The calotte 6 is visibly thinner than theannula~ bottom section 5.
As far as heretofore described, the design of the
bottom corresponds basically to the design of the bottom of
the container according to Figure 5 of ~.S. patent No.
3,369,694.
The annular section 5 has, however, additional
deformations. In the example according to Figures 1 and 2,
B
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this deformation consists of an annular bead 7 which has a
radially inside flange forming a direct continuation of the
calotte section 6. The bead 7 projects axially downwardly
although it may slope toward the inside (not illustrated).
The axial projection of the crest of the bead 7 relative to
the annular section 5 from the outward delimiting edge 4 is
identified by the numeral 10 and is less than 2 mm in a
customary size beverage can made of metal. The axial dis-
tance 10 is preferably from about 0.2 to 0.4 mm.
The angle between the annular section 5 and the
can body 1 is identified by the numeral 11 in Figure 1 and
the numeral 25 in Figure 7. This angle can be larger than
90 (Figure 7) in a preferred example of embodiment, but
also smaller than 90. Due to the preferred inclination of
the annular section 5, the radial inner delimiting edge of
the annular section as related to the outer delimiting edge
4 is spaced downwardly.
The axial distance between the highest point of
the calot~e shaped section and of the deepest point of the
annular bottom section is represented by the numeral 9. It
is recognized that this axial height 9 is comparably small.
A better stability of the empty container over the prior art
is nevertheless provided as was demonstrated by thorough
tests.
In the example of embodiment according to Figures
3 and 4, there is a flat bead 12 which projects into the
interior of the container and spans the entire width of the
annular section between the delimiting edges 13 and 14.
The axial depth of deformation of the bead 12 is designated
by the numeral 10.
In the exmaple of embodiment according to Figure
5, the width of the annular bead 1~ is limited to a fraction
of the width of the annular section whereby on both sides of
the bead there remain flat sections 19 and 20 of the annular
section.
In the example of embodiment according to Figure -
6, there is an axially downwardly projecting bead 22 combined
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with a bead 23 projecting axially into the interior of the
can. The bead 23 is directly adjacent to the calotte area 6.
In a preferred example of embodiment, the bead 23 can be
omitted. seside the outwardly projecting bead 22, there is
still a plane or flat annular area of the bottom section 5
left. While in the heretofore described examples of embodi-
ments the deformations are made annularly, it is equally
feasible to make crown-shaped divided deformations in the
annular bottom section 5.
In the example of embodiment according to Figure
7, radially extending depressions 27 are provided which
extend between the edge 13 of the dome 6 and the edge 13
and the edge 14 and of the truncated portion 3. The depres-
sions widthwise (circumferentially of the can) are of the
order of those shown at 30 in ~igure 11.
In the example of embodiment according to Figures
8 and 9, there are at least four circumferentially spaced,
equally cup-shaped depressions or dimples 28 provided in the
bottom section 5. The depressions extend into the interior
of the body of the can. The dimples 28 intersect the radi-
ally inner limiting edge of the annular bottom section 5 as
clearly shown in Figures 8 and 9. Instead of four, a greater
number of cup-shaped deformations can be provided as indicated
in dash lines at 28a.
In the example of embodiment according to Figures
10 and 11, the cup-shaped depressions of the embodiment of
Figures 8 and 9 are elongated in a radial direction to extend
over the entire width of the annular section 5 so that the
outside placed ends of the depressions 30 or 30a penetrate
into the frustoconical transitional section 3.
In the example of Figures 12 and 13, there are
cup-shaped depressions 35 which have a basically radial extent
approximately equal to the radial width of the annular sec- -
tion 5. The cup-shaped depressions 3; are appropriately
limited on the radially outwardly direc~ed side and to both
circumferential sides by steep walls, in the bottom area and
in the radially inner area. However~ a continuous flat wall
34 is provided.
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In the examples of Figures 14 and 15, the depres-
sions 38, 39 are arranged in crown shape and are divided
into two different pitch circles 40, 41. In the example of
embodiment according to Figures 14 and 15, the deformations
are longer in radial direction than in circumferential direc-
tion. They are spaced in the circumferential direction by a
gap whereby adjacent depressions 38, 39 in the circumferential
direction are assigned to different pitch circles overlap in
radial direction. A joint line, concentric with the can axis
is eliminated. The bottom thus has an extraordinary stiffness,
so that the deformations are kept within limits. Further, the
calotte area being subjectto only a slight expansion, takes
only a slight portion of the usable volume.
In the embodiment of Figures 16 and 17, the two
different diameter pitch circles have formed thereon circular
depressions 45, 46. The depressions 45 are of larger di-
ameter than the depressions 46.
The above-described cans are all in the as formed
non-pressurized state. That is, the cans have not been filled
with any product and have not been internally pressurized by
any gaseous pressure.
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