U.S. patent application number 14/368985 was filed with the patent office on 2014-12-04 for can with a polygonal cross section.
The applicant listed for this patent is Brasilata S.A. Embalagens Metalicas. Invention is credited to Antonio Carlos Teixeira Alvares, Silverio Candido Da Cunha.
Application Number | 20140353319 14/368985 |
Document ID | / |
Family ID | 47562889 |
Filed Date | 2014-12-04 |
United States Patent
Application |
20140353319 |
Kind Code |
A1 |
Alvares; Antonio Carlos Teixeira ;
et al. |
December 4, 2014 |
Can with a Polygonal Cross Section
Abstract
The present can includes a tubular body (C) formed by lateral
walls of rectangular contour and which are connected, two by two,
by longitudinal edges, said tubular body (C) being closed by an
upper wall and a lower wall. Each lateral wall incorporates a
structural reinforcing means defined by a plurality of depressions
having a polygonal or circular contour and located side by side,
without overlapping and occupying at least one portion of the area
of each lateral wall
Inventors: |
Alvares; Antonio Carlos
Teixeira; (Sao Paulo, BR) ; Da Cunha; Silverio
Candido; (Lajeado, BR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Brasilata S.A. Embalagens Metalicas |
Sao Paulo |
|
BR |
|
|
Family ID: |
47562889 |
Appl. No.: |
14/368985 |
Filed: |
December 18, 2012 |
PCT Filed: |
December 18, 2012 |
PCT NO: |
PCT/BR2012/000528 |
371 Date: |
June 26, 2014 |
Current U.S.
Class: |
220/660 |
Current CPC
Class: |
B65D 1/18 20130101; B65D
7/06 20130101; B65D 7/46 20130101; B65D 1/40 20130101 |
Class at
Publication: |
220/660 |
International
Class: |
B65D 1/18 20060101
B65D001/18; B65D 1/40 20060101 B65D001/40 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 27, 2011 |
BR |
PI 1105354-2 |
Claims
1. A can with a polygonal cross section, comprising a tubular body
formed by lateral walls of rectangular contour and which are
connected, two by two, by longitudinal edges, said tubular body
being closed by an upper wall and a lower wall, the can being
characterized in that each lateral wall incorporates a structural
reinforcing means defined by a plurality of depressions, having a
contour selected between the polygonal and circular shapes and
located side by side, without overlapping and occupying at least
one portion of the area of each lateral wall.
2. The can, according to claim 1, characterized in that the contour
area of each depression corresponds from 1/16 to 1/8 of the area of
the lateral wall, and in that the depth of each depression is
defined between 0.1 to 20 times the thickness of the metallic
sheet.
3. The can, according to claim 1, characterized in that the depth
of the depressions, in each lateral wall of the tubular body, is
progressively reduced in the vertical direction, from the lower
depressions toward the upper depressions.
4. The can, according to claim 3, characterized in that each
depression has a bottom wall projecting toward the interior of the
tubular body, the depth of the depressions in each lateral wall of
the tubular body being progressively reduced according to a plane
inclined in relation to said lateral wall and containing the bottom
walls of the depressions.
5. The can, according to claim 4, characterized in that the
depressions are frusto-conical
6. The can, according to claim 5, characterized in that the
frusto-conical depressions are approximately tangent to each
other.
7. The can, according to claim 4, characterized in that the
depressions are truncated pyramids having rectangular bases and
rounded corners.
8. The can, according to claim 7, characterized in that the
depressions are spaced from each other by a distance corresponding
from 1/40 to 1/20 of the width of the lateral wall.
Description
FIELD OF THE INVENTION
[0001] The present invention refers to a can with a tubular body
having a horizontal cross section of polygonal shape, usually
square or rectangular, and end edges to which are respectively
affixed, for example by means of a double seam, a bottom wall and
an upper wall, which may be annular, having a large discharge
opening closed by a pressure lid, or of the integral type provided
with a small discharge opening closed by a respective lid. The
invention allows the subject can to be used to contain several
types of bulk products in the liquid, paste or particulate
state.
BACKGROUND OF THE INVENTION
[0002] Metallic sheet containers are well known in the art, taking
the form of cans with a lateral wall of square, rectangular or
cylindrical contour, and having an integral upper wall provided
with a small discharge opening, or an annular upper wall provided
with a large discharge opening, in which is defined a closing seat
for the seating of a pressure lid.
[0003] The tubular body of this type of can is usually obtained
from conventional operations of cutting the metallic sheet,
calendering the metallic sheet into a tubular cylindrical shape,
and longitudinally welding or seaming the metallic sheet, for
laterally closing the tubular body of the can.
[0004] Aiming at increasing the structural strength of the lateral
wall of the tubular body, the latter is often submitted to an
operation, usually in a milling machine, to form, in the lateral
wall of the cylindrical tubular body, a plurality of structural
circumferential ribs, adjacent or axially spaced from each other
and projecting slightly inwardly or outwardly of the tubular body
of the can.
[0005] Said ribs are obtained by deformation of the lateral
cylindrical wall of the tubular body, allowing for the increase of
the structural resistance of the lateral wall in the radial
direction and, consequently, the production of a can with a thinner
metallic sheet, thereby significantly reducing the cost of the
final product.
[0006] The above mentioned constructive solution is more suitably
applied to cans having a cylindrical tubular body, in which the
continuous cylindrical ribs do not cause relevant structural
weakening of the can in the axial direction. In said cans, the
thickness of the metallic sheet may be reduced, since said
reduction is compensated by the increased structural resistance to
radial loads, and the resistance to the compression loads is not
reduced to levels at which the structure of the can is compromised
when filled and submitted to stacking.
[0007] However, in the case of cans presenting a polygonal cross
section, more specifically the cans with a square cross section
having rounded longitudinal edges, the provision of such structural
ribs with a continuous circumferential development, for increasing
the resistance of the walls to radial loads and for allowing
reducing the thickness of the metallic sheet, has not shown to be
acceptable. Said ribs weaken, beyond acceptable levels, the
longitudinal edges of the can, which undergo a great reduction in
their resistance to axial compression loads, impairing the
operation of the can.
[0008] The attempts to compensate the thickness reduction of the
metallic sheet, in cans having a square cross section, by providing
continuous circumferential ribs, have not reached a satisfactory
result due to the degree of weakening generated on the longitudinal
edges of the can.
[0009] Due to the aforementioned drawback, it has been proposed the
provision of structural ribs only in the lateral wall portions of
the can, that is, at the panels which define the lateral walls of a
can presenting a square or rectangular cross section.
[0010] Patent application BR PI 9801887-6 and in its Certificates
of Addition C1 and C2 with the same number (U.S. Pat. No. 6,712,575
B1) of the same assignee, propose a technical solution which
provides the structural ribs only in the portions of lateral wall
(the lateral panels) of the tubular body of the can, which solution
comprises the provision of the aforementioned continuous
circumferential ribs on the still cylindrical tubular wall,
followed by the expansion of the tubular body into the desired
polygonal cross section, whereby the circumferential ribs are
eliminated at the region of the rounded edges of the expanded
polygonal tubular body.
[0011] Although allowing for the production of a can having a
polygonal contour with a structure significantly more resistant
than those without ribs, said prior solution still presents one
aspect to be improved, resulting from the fact that the regions in
which are formed the longitudinal edges of the can, which regions,
initially provided with ribs in the cylindrical tubular body, are
afterwards deformed for eliminating said ribs from said regions,
upon the expansion of the cylindrical tubular body into the desired
polygonal shape. Said deformation of the metallic sheet in opposite
directions, in the regions of the longitudinal edges of the can,
causes some material fatigue which, in addition to the fact that
the deformation of the metallic sheet back to the original
condition is not complete, prevents the structural resistance of
the can, particularly to compression radial loads, from reaching
even higher values.
[0012] Aiming at minimizing the undesirable effects of the double
deformation of the metallic sheet in the region of the longitudinal
edges of the can, the same assignee proposed, in the Certificates
of Addition C2 BR C2 9801887-6, to provide longitudinal rib
extensions at said edges of the can. Although providing new axial
structural strengthening elements, said longitudinal rib extensions
at the longitudinal edges of the can did not eliminate the effects
of the double deformation of the metallic sheet, as mentioned
above, thereby maintaining the limitation regarding the achievement
of a substantial increase of the structural resistance of the
can.
[0013] Due to the aforementioned limitations, it has been proposed
the solution object of the patent document BR PI 0003728-1 (WO
0197998 A1) of the same assignee, according to which only the
lateral walls of the can (of polygonal cross section, usually
square) are provided with circumferential and longitudinal ribs,
having a substantially increased structural resistance, without
causing weakening of the longitudinal edges of the can and allowing
reducing the thickness of the sheet metallic used to build the
lateral walls of the can.
[0014] In this prior art solution, as commented above, the
cylindrical tubular body of the can is expanded without forming any
extension of structural rib, either on the flattened lateral walls,
or on the rounded longitudinal edges matching with the adjacent
flattened lateral walls. Each of the flattened lateral walls are
then provided with a plurality of transversal rib extensions and
with at least one longitudinal rib extension, said rib extensions
being defined by means of a radial plastic deformation of the
respective region of the flattened lateral walls of the tubular
body. Usually, each lateral wall is provided with transversal rib
extensions, which may be adjacent to each other or spaced apart,
and with two longitudinal rib extensions, located next to the
longitudinal edges of the can.
[0015] Although leading to an increase in the structural resistance
of the can and to the possibility of reducing the metallic sheet
thickness, the prior art constructive solution still causes the
structural resistance of the can, to the compression loads and to
the expansion loads resulting from internal pressure, to largely
depend on the thickness of the metallic sheet, that is, on the
resistance of the latter to the radial expansion loads and to the
compression axial loads acting on the lateral walls of the can.
[0016] From the above, it is thus desirable to search for a
technical solution which is able to provide structural resistance
to a can of the type considered herein, by using a thinner metallic
sheet.
SUMMARY OF THE INVENTION
[0017] The present invention has the object of providing a can
having a polygonal cross section, usually square or rectangular,
having lateral walls presenting a desired structural resistance
against radial and axial loads, by using a metallic sheet thinner
than that usually required to achieve the same structural
resistance.
[0018] The present invention has also the object of providing a can
with a polygonal cross section as mentioned above, which may have
the flattened lateral walls of the tubular body thereof easily
reinforced by radial and localized plastic deformations, as a
function of the different load levels to which said walls are
submitted.
[0019] The present can comprises a tubular body formed by lateral
walls of rectangular contour and which are connected, to by two, by
longitudinal edges, said tubular body being closed by an upper wall
and a lower wall.
[0020] According to the invention, each lateral wall incorporates a
structural reinforcing means defined by a plurality of depressions
of polygonal or circular contour, located side by side, without
overlapping and occupying at least one portion of the area of each
respective lateral wall, thus allowing to provide, to each area of
a lateral wall of the can, the required resistance to withstand the
axial compression loads and radial expansion loads.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The invention will be described below, with reference to the
attached drawings, given by way of example of a possible embodiment
of the invention, and in which:
[0022] FIG. 1 illustrates a partially cut perspective view of the
tubular body of a can built according to the prior art and having
each of the lateral walls thereof provided with a first type of
known structural reinforcing means, in the form of transversal and
longitudinal rib extensions projecting to the interior of the
tubular body;
[0023] FIG. 2 is a perspective view of the tubular body of a can
similar to that of FIG. 1, but having each of the lateral walls
thereof provided, according to a first constructive variant of the
present invention, with a first type of structural reinforcing
means, defined by truncated pyramid depressions of rectangular
bases, with no overlapping and occupying the area of each lateral
wall of the tubular body of the can;
[0024] FIG. 2A illustrates a lateral view of the tubular body of
the can of FIG. 2;
[0025] FIG. 2B illustrates a partially cut view of the lateral wall
of the can, taken according to line II-II in FIG. 2A;
[0026] FIG. 3 illustrates a perspective view of the tubular body of
a can similar to that of FIG. 2, having the lateral walls thereof
each provided with a second type of structural reinforcing means,
according to a second constructive embodiment of the present
invention, defined by frusto-conical depressions of rectangular
bases, with no overlapping and occupying the area of each lateral
wall of the tubular body of the can;
[0027] FIG. 3A illustrates a lateral view of the tubular body of
the can of FIG. 3; and
[0028] FIG. 3B illustrates a partially cut view of the lateral wall
of the can, taken according to line III-III in FIG. 3A.
DETAILED DESCRIPTION OF THE INVENTION
[0029] In the construction illustrated in the attached drawings,
the present can is of the type which comprises a tubular body C
having a horizontal cross section with a square contour, having
four lateral walls 10 of rectangular contour (only two being
illustrated in FIG. 1), an upper wall 11 and a lower wall 12, both
of integral metallic sheet and having the peripheral portions
thereof respectively affixed, usually by double seaming, to an
upper end edge 10a and a lower end edge 10b of the lateral walls
10.
[0030] The four lateral walls 10 are connected to each other by
longitudinal edges 13, which are rounded and match with the
adjacent lateral walls 10 which are flat. In the construction
illustrated in FIG. 1, the upper wall 11 is further provided with a
small discharge opening 14, closed by a suitable lid, and also with
a small suspension handle 15.
[0031] In the embodiment illustrated in FIGS. 2 and 3, the upper
wall 11 may be in the form of a structural ring, peripherally
seamed to the lateral walls 10 and having an inner opening which
defines a seat, onto which is seated and axially retained a known
pressure lid 16.
[0032] The formation of the can may be obtained by the known steps
of cutting a metallic sheet of predetermined thickness and having
dimensions designed to form, after its bending and longitudinally
seaming or welding, a cylindrical tubular body C with a perimeter
substantially equal to the perimeter of the polygonal section of
the can to be produced.
[0033] The tubular body C, still in the form of a calendered
cylinder, is then expanded so that the cylindrical lateral wall is
radially deformed, as illustrated in FIG. 1, into the desired
format of polygonal cross section, with flattened lateral walls 10
connected by longitudinal edges 13, rounded and matching with the
adjacent lateral walls 10.
[0034] After the tubular body C is expanded into a polygonal shape,
the deformation of the flattened lateral walls is carried out, in
order to provide them with structural reinforcing means, as
described below.
[0035] FIG. 1 illustrates a prior art embodiment, object of BR PI
003728-1 (WO 0197998A1), according to which each lateral wall 10 of
the tubular body C is provided with a first type of structural
reinforcing means, defined by a plurality of transversal ribs 20
located in planes orthogonal to the axis of the tubular body C, and
by a pair of longitudinal ribs 30, each being located next to one
of the longitudinal edges 13 and which, in the illustrated
embodiment, are connected to the ends of the transversal ribs
20.
[0036] In the embodiment illustrated in FIG. 1, said ribs 20, 30
project inward to the tubular body C.
[0037] FIGS. 2, 2A and 2B illustrate a tubular body C built in a
manner similar to that described for the can of FIG. 1, but having
the four lateral walls 10 thereof provided with a first variant of
the structural reinforcing means of the invention, which is defined
by a plurality of truncated pyramid depressions 50, of rectangular
bases and rounded corners, located side by side, without
overlapping and occupying at least one portion of the area of each
respective lateral wall of the tubular body C of the can.
[0038] In the illustrated embodiment, the truncated pyramid
depressions 50 are spaced apart from each other by a distance which
corresponds to 1/40 to 1/20 of the width of the lateral wall
10.
[0039] It should be understood that the depth, the dimensions of
the contour and the inclination of the lateral walls of each of the
truncated pyramid depressions 50 are defined as a function of the
degree and type, radial and axial, of structural resistance to be
provided to the lateral walls 10 of the tubular body C.
[0040] For square 18 liter cans, the truncated pyramid depressions
50 were produced with a depth sufficient to provide, to the
respective portion of area of the lateral wall, the required
resistance to the compression axial loads and expansion radial
loads resulting from the weight of the liquid, paste or granular
product contained in the can.
[0041] The inclination of the lateral walls of each truncated
pyramid depressions 50 is defined so as to impart the necessary
strength to the wall in the radial direction, without impairing the
structural resistance to the compression axial loads.
[0042] The contour of said truncated pyramid depressions 50 is
dimensioned to define an area corresponding from about 1/16 to 1/8
of the area of the respective lateral wall 10 in which said
truncated pyramid depressions 50 are provided.
[0043] Generally, the depth of the truncated pyramid depressions 50
is about 0.1 to 20 times the thickness of the metallic sheet.
[0044] Each truncated pyramid depressions 50 has a bottom wall 51
projecting inward of the tubular body C. However, it should be
understood that said depressions may have to be produced, from the
inside to the outside, in each lateral wall 10, in order that the
bottom walls 51 are kept projecting outwardly from the plane of the
respective lateral wall 10.
[0045] As it will be seen below, this first variant of the
reinforcing means of the invention, illustrated in FIGS. 2, 2A and
2B, provided a substantial increase of the structural resistance of
the lateral walls 10 of the can, when submitted to compression
loads resulting from stacking the cans.
[0046] FIGS. 3, 3A and 3B illustrate a tubular body C built in a
manner similar to that described for the can of FIGS. 1 and 2, but
having the four lateral walls 10 thereof provided with a second
variant of the structural reinforcing means of the invention, which
is defined by a plurality of frusto-conical depressions 60, located
side by side, without overlapping and occupying at least one
portion of the area of each respective lateral wall 10 of the
tubular body C of the can.
[0047] In the configuration illustrated in FIGS. 3, 3A and 3B, the
frusto-conical depressions 60 occupy the entire area of each
lateral wall 10, being located approximately tangent to each
other.
[0048] Similarly to the above description related to the embodiment
of FIGS. 2, 2A and 2B, the depth and dimensions of the contour and
the inclination of the lateral walls of each of the frusto-conical
depressions 60 are defined as a function of the degree and type,
radial and axial, of the structural resistance to be provided to
the lateral walls 10 of the tubular body C.
[0049] For square 18 liter cans, the frusto-conical depressions 60
were produced with a depth sufficient to provide, to the respective
area portion of the lateral wall, the required structural
resistance to the compression axial loads and to the expansion
radial loads.
[0050] The inclination of the lateral walls of each frusto-conical
depression 60 is defined so as to impart the necessary structure to
the wall in the radial direction, without compromising the
structural resistance to the axial compression loads. In the case
of the frusto-conical depressions 60, the inclination of the
lateral walls has less influence in the resistance of the lateral
walls to the axial compression loads, due to the circular contour
of said depressions 60.
[0051] The contour of said frusto-conical depressions 60 is
dimensioned to define an area corresponding from about 1/16 to 1/8
of the area of the respective lateral wall 10 into which said
depressions are provided.
[0052] Generally, the depth of the frusto-conical depressions is
about 0.1 to 20 times the thickness of the metallic sheet. Each
frusto-conical depression 60 has a bottom wall 61 projecting to the
interior of the tubular body C. However, it should be understood
that said depressions may have to be produced from the inside to
the outside, in each lateral wall 10, in order that the bottom
walls 61 are kept projecting outwardly from the plane of the
respective lateral wall 10.
[0053] As commented below, this second variant of the reinforcing
means of the invention, illustrated in FIGS. 3, 3A and 3B
presented, in relation to the first variant of FIGS. 2, 2A and 2B,
an even larger increase of the structural resistance of the lateral
walls 10 of the can, when submitted to compression loads resulting
from stacking the cans.
[0054] Table I below illustrates the result of the tests conducted
with the three structural reinforcing means illustrated in FIGS. 1
to 3B, in order to simulate the conditions of the axial compression
to which a filled can is subject, and onto which are stacked 10
cans also filled with a material having a specific weight
substantially equal to water.
[0055] Forces equivalent to the stacking were applied onto the can
and there were used cans having different metallic sheet thickness:
0.27 mm which is the commonly used; 0.22 mm and 0.19 mm.
TABLE-US-00001 TABLE I Depression Sheet thickness Lateral wall
profile/FIG. (mm) deformation (mm) 0.27 0.111e-3 1 0.22 0.210e-3
0.19 0.282e-3 0.27 0.107e-3 2 0.22 0.167e-3 0.19 0.232e-3 0.27
0.102e-3 3 0.22 0.145e-3 0.19 0.188e-3
[0056] As can be noted, the structural reinforcing means of FIGS. 2
and 3 were those that resulted in the smaller deformations of the
lateral wall 10, particularly in relation to the deformations of
the prior art construction represented in FIG. 1, under the same
compression conditions, especially in the tests which used metallic
sheets having the thickness reduced to the values of 0.22 and 0.19
mm.
[0057] The structural reinforcing means defined by the frusto
conical depressions 60 (illustrated in FIGS. 3, 3A and 3B)
presented the best results, and it should be also noted that these
frusto-conical depressions 60 have the further advantage of not
leading to the concentration of residual stresses in specific
points of the depressions, allowing these stresses to be
distributed along the entire extension of said frusto conical
depressions 60.
[0058] The frusto-conical shape, which may be derived to the format
of a truncated spherical cap, when applied to depressions having
the bottom wall 61 projecting inwardly of the tubular body C of the
can, provides the lateral wall 10 with an increased resistance to
deformation, caused not only by the internal pressures of the
product stored in a filled can, but mainly by the compression loads
caused by stacking cans in a filled condition.
[0059] As can be better observed in FIGS. 2B and 3B of the
drawings, the truncated pyramid depressions 50 and frusto conical
depressions 60 may have their depth progressively reduced in the
vertical direction, from the lowermost depressions 50, 60 toward
the uppermost depressions 50, 60 in each lateral wall 10 of the
tubular body C.
[0060] The depth variation of the depressions 50, 60 of both
constructive forms is possible due to the fact that the lower
regions and median regions of each lateral wall 10 undergo a
greater lateral pressure produced by the filled product, and also
by the vertical loads in the case of stacking the cans.
[0061] With the new construction of the structural reinforcing
means for the lateral walls 10 of the tubular body C of the can, it
becomes possible to obtain a can with a polygonal cross section
having both a reduced metallic sheet thickness and the desired
structural resistance.
[0062] Although not illustrated herein, it should be understood
that the depth of the depressions 50, 60 in each lateral wall 10 of
the tubular body C may be optionally and progressively reduced in
the horizontal direction, from the median depressions toward the
lateral depressions adjacent to the longitudinal edges 13 of the
tubular body C. The progressive depth reductions of the depressions
50, 60 may occur in the vertical and horizontal directions, either
alternatively or simultaneously.
[0063] In both constructive forms illustrated for the depressions
50, 60, the depth of each lateral wall 10 of the tubular body C is
progressively reduced, according to a plane P inclined in relation
to said lateral wall 10 and comprising the bottom walls 51 and 61
of the depressions 50, 60.
[0064] It should be further understood that the depth variation of
the depressions 50, 60 of each lateral wall 10 may be carried out
in each depression, according, at least, to one of the
aforementioned vertical and horizontal directions. In this case,
the bottom walls 51, 61 of the depressions 50, 60 remain located in
planes parallel in relation to the plane of the respective lateral
wall 10, but spaced therefrom by different values defined as a
function of the depth to be imparted to each of the depressions 50,
60.
[0065] It should be understood that modifications in the dimension,
shape and number of the structural reinforcing depressions may be
carried out, without departing from the inventive scope defined by
the accompanying claims.
* * * * *