Strengthened food container and method

Abstract

A metal food can including a metal sidewall is provided. The diameter of the sidewall varies at different axial positions along the sidewall. The can includes a can end coupled to an end of the metal sidewall, and a plurality of circumferential beads formed in the metal sidewall. The shape of each circumferential bead varies based upon the diameter of the section of the sidewall in which the beads are formed.

Description

BACKGROUND OF THE INVENTION

The present invention relates generally to the field of containers. The present invention relates specifically to a metal food can having a non-cylindrical, strengthened sidewall.

SUMMARY OF THE INVENTION

One embodiment of the invention relates to a metal food can including a metal sidewall having an axial center point. The diameter of the sidewall varies at different axial positions along the sidewall. The can includes a can end coupled to an end of the metal sidewall, and a plurality of circumferential beads formed in the metal sidewall. The shape of each circumferential bead varies based upon the diameter of the section of the sidewall in which the beads are formed.

Another embodiment of the invention relates to a metal can for holding and storing food. The metal can includes a container end and a non-cylindrical metal sidewall. The metal sidewall includes a center section having a first diameter and an upper sidewall section located above the center section having a second diameter different than the first diameter. The upper sidewall section extends radially relative to the center section to provide the transition from the first diameter to the second diameter. The metal sidewall includes a lower sidewall section located below the center section having a third diameter different than the first diameter, and the lower sidewall section extends radially relative to the center section to provide the transition from the first diameter to the third diameter. The metal sidewall includes a plurality of circumferential beads formed in the metal sidewall each having a bead depth. At least one circumferential bead is formed in each of the center section, the upper sidewall section and the lower sidewall section.

Another embodiment of the invention relates to a metal can for holding food. The can includes a first end wall and a metal sidewall, and the metal sidewall includes an upper end. a lower end and a cylindrical center section having a first diameter. The non-cylindrical upper sidewall section is located between the center section and the upper end. The upper sidewall section includes an upper maximum diameter greater than the first diameter. The diameter of the upper sidewall section increases between the center section and the upper maximum diameter to provide the transition from the first diameter to the upper maximum diameter, and the diameter of the upper sidewall section decreases between the upper maximum diameter and the upper end of the sidewall. The non-cylindrical lower sidewall section is located between the center section and the lower end. The lower sidewall section includes a lower maximum diameter greater than the first diameter. The diameter of the lower sidewall section increases between the center section and the lower maximum diameter to provide the transition from the first diameter to the lower maximum diameter, and the diameter of the lower sidewall section decreases between the lower maximum diameter and the lower end of the sidewall. The can also includes a plurality of circumferential beads formed in the metal sidewall, and a circumferential bead is formed in each of the center section, the upper sidewall section and the lower sidewall section. The first end wall is coupled to either the upper end or the lower end of the metal sidewall.

Another embodiment of the invention relates to metal food can including a metal sidewall having an axial center point. The diameter of the sidewall varies at different axial positions along the sidewall. The can includes a can end coupled to an end of the metal sidewall, and the can end has an end diameter. The can includes a plurality of circumferential beads formed in the metal sidewall, and the shape of each circumferential bead varies based upon the diameter of the section of the sidewall in which the beads are formed. The metal sidewall has a first diameter at the axial center point and a maximum diameter at a position between the axial center point and the can end, and the maximum diameter is greater than both the first diameter and the end diameter.

Another embodiment of the invention relates to a method of forming a beaded metal food can. The method includes providing a cylindrical metal tube having an upper edge defining an upper opening and a lower edge defining a lower opening. The method includes forming a plurality of circumferential beads in the cylindrical metal tube. The method includes shaping the cylindrical metal tube to form a non-cylindrical metal sidewall, after forming the plurality of circumferential beads.

Alternative exemplary embodiments relate to other features and combinations of features as may be generally recited in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

This application will become more fully understood from the following detailed description, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements in which:

FIG. 1A is a front elevation view of a container, according to an exemplary embodiment;

FIG. 1B is a top perspective view of the container of FIG. 1A, according to an exemplary embodiment;

FIG. 2 is a sectional view along the longitudinal axis of the container of FIG. 1A, according to an exemplary embodiment;

FIG. 3 is an enlarged view of a portion of the container shown in FIG. 2;

FIG. 4 is a front elevation view of a container according to another exemplary embodiment;

FIG. 5 is a front elevation view of a container according to another exemplary embodiment;

FIG. 6 shows a method of making a container according to an exemplary embodiment;

FIG. 7 shows the profile shape of a container sidewall prior to formation of beads according to an exemplary embodiment;

FIG. 8 is a detailed sectional view showing an end wall attached to a sidewall via double seam according to an exemplary embodiment;

FIG. 9 is a sectional view taken along the longitudinal axis of the container of FIG. 4 according to an exemplary embodiment;

FIG. 10 is an enlarged view of a portion of the container shown in FIG. 9;

FIG. 11 is a front elevation view of a container according to another exemplary embodiment; and

FIG. 12 is an enlarged view of a portion of the container shown in FIG. 11.

DETAILED DESCRIPTION

Before turning to the figures, which illustrate the exemplary embodiments in detail, it should be understood that the present application is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology is for the purpose of description only and should not be regarded as limiting.

Referring generally to the figures, various embodiments of a strengthened food container are shown. Specifically, the embodiments relate to metal food cans having a sidewall including at least one non-cylindrical sidewall portion and strengthening beads formed in the sidewall. In various embodiments, the containers discussed herein are configured to contain foods at a negative internal pressure (e.g., cans in which the pressure within the can following sealing is less than the atmospheric pressure) and the negative internal pressure results in an inwardly directed force on the sidewall of the can. In some embodiments, the food container is filled with a hot, cooked food product and the container is sealed while the food is hot. As the food cools within the sealed can, the pressure within the interior of the can decreases relative to atmospheric pressure resulting in an inwardly directed force on the container. The beads act to provide strength to the sidewall, and the beaded sidewalls discussed herein are configured to provide support to a non-cylindrical metal sidewall, particularly against the inwardly directed force.

Referring to FIG. 1A and FIG. 1B, a container, shown as metal food can 10, is shown according to an exemplary embodiment. Can 10 includes a first container end, shown as an upper end wall 12, and a second container end, shown as lower end wall 14. Can 10 also includes a sidewall 16. Generally, upper end wall 12 is coupled to an upper end of sidewall 16, and lower end wall 14 is coupled to a lower end of sidewall 16. As shown, upper end wall 12 and lower end wall 14 are can ends designed to be removed using a tool, such as a can opener.

Sidewall 16 is a metal sidewall and is coupled to upper end wall 12 and lower end wall 14 via hermetic seams. A first seam 20 joins upper end wall 12 to sidewall 16, and a second seam 22 joins lower end wall 14 to sidewall 16. In the embodiment shown, seams 20 and 22 are hermetic double seams (shown in detail in FIG. 8) formed of interlocked and crimped sections of the upper and lower edges of sidewall 16 and of the periphery of end walls 12 and 14, respectively.

Generally, sidewall 16 is a non-cylindrical sidewall (e.g., a sidewall in which the cross-sectional shape varies at different positions along the axial length of the sidewall, a sidewall in which the cross-sectional area varies at different positions along the axial length of the sidewall, a sidewall having a generally circular cross-sectional shape but in which the cross-sectional diameter varies at different positions along the axial length of the sidewall, etc.). In the embodiments shown in the FIGS., sidewall 16 is a substantially circular shaped sidewall having different diameters at different axial positions along the length of the sidewall. Referring in particular to FIG. 1A and FIG. 2, sidewall 16 includes a center section, shown as center portion 24, an upper sidewall section, shown as upper portion 26, and a lower sidewall section, shown as lower portion 28. Generally, center portion 24 is a centrally located portion of sidewall 16 in which the axial center point of the sidewall is located, upper portion 26 is a sidewall section extending from an upper end of center portion 24, and lower portion 28 is a sidewall section extending from a lower end of center portion 24.

In the embodiment shown, center portion 24 has a diameter D1, and in the embodiment shown, center portion 24 is a substantially cylindrical section (e.g., a section in which cross-sectional shape and area remain the same at all axial positions along the section) such that D1 remains constant, for at least a portion of the axial length of center portion 24. Upper portion 26 extends upward from center portion 24 and extends radially outward relative to center portion 24, and lower portion 28 extends downward from center portion 24 and extends radially outward relative to center portion 24. Upper portion 26 includes a diameter D2, and lower portion 28 includes a diameter D3. As shown, both D2 and D3 are greater than D1. In this embodiment, upper portion 26 is outwardly angled and provides the transition from the small diameter of D1 to the greater diameter of D2, and lower portion 28 is outwardly angled and provides the transition from the small diameter of D1 to the greater diameter of D3. Thus, in this embodiment, the diameter of sidewall 16 increases from the upper end of center portion 24 to D2, and the diameter of sidewall 16 increases from the lower end of center portion 24 to D3. In other embodiments, D1 may be greater than D2 and/or D3 such that the sidewall portions immediately above and/or below center portion 24 angle radially inward relative to the center section. In another embodiment, D2 may be the same as D1 such that both upper portion 26 and center portion 24 have substantially the same diameter and shape as each other, and in this embodiment, D3 may be different from both D2 and D1 such that only lower portion 28 has a non-cylindrical shape. In another embodiment, D3 may be the same as D1 such that both lower portion 28 and center portion 24 have substantially the same diameter and shape as each other, and in this embodiment, D2 may be different from both D3 and D1 such that only upper portion 26 has a non-cylindrical shape.

As shown in FIG. 2, sidewall 16 is shown prior to the attachment of upper and lower can ends 12 and 14, and includes an upper flange 30 and a lower flange 32. Upper flange 30 is an outwardly curled section of metal contiguous with the rest of sidewall 16 and is configured to be interlocked and crimped with an outer peripheral section of upper can end 12 to form seam 20 (shown in FIG. 1A). Lower flange 32 is an outwardly curled section of metal contiguous with the rest of sidewall 16 and is configured to be interlocked and crimped with an outer peripheral section of lower can end 14 to form seam 22 (shown in FIG. 1A). Upper section 26 continues to extend radially outward beyond the portion labeled D2 to join to flange 30, and lower section 28 continues to extend radially outward beyond the portion labeled D3 to join to flange 32. In other embodiments, both upper section 26 and lower section 28 may curve radially inward to join to flanges 30 and 32, respectively.

In the embodiment shown, sidewall 16 is sized and shaped to be coupled to upper and lower can ends that have different diameters from each other. Sidewall 16 has an upper diameter D4 and lower diameter D5, and upper and lower diameters D4 and D5 are selected such that the final, sealed can 10 has end walls of two different sizes. In the embodiment shown, D4 is greater than D5 such that the diameter of lower end wall 14 is smaller than the diameter of upper end wall 12. In one embodiment, D4 is 2.88 inches plus or minus a half inch, and in another embodiment, D4 is 2.880 inches plus or minus 0.005 inches. In one embodiment, D5 is 2.76 inches plus or minus a half inch, and in another embodiment, D5 is 2.760 inches plus or minus 0.005 inches.

As shown in FIG. 2, the portion of upper sidewall section 26 extending from the upper end of center portion 24 to the location of D2 is a substantially straight segment (e.g., non-curved, annular, etc.), and the portion of lower sidewall section 28 extending from the lower end of center portion 24 to the location of D3 is a substantially straight segment (e.g., non-curved, annular, etc.). In other embodiments, upper sidewall section 26 and/or lower sidewall section 28 may include one or more curved sections. It should be understood, that the general shape and dimensions of sidewall 16 discussed herein refer to the shape and dimensions of the sidewall sections generally (e.g., if the shape and dimensions of the beads are ignored), and are not intended to relate to the localized shape and dimension variability introduced by the beads. For example, center portion 24 is generally cylindrical with a constant diameter if the localized variability of the beads in center portion 24 are ignored or averaged. The same applies to upper portion 26 and lower portion 28.

In various embodiments discussed herein, can 10 includes a series of beads that act to strength the non-cylindrical of the can against inwardly directed forces. In the various embodiments discussed herein, beads are formed in the non-cylindrical portions of the sidewall and act to strengthen the sidewall against inwardly directed forces. In the embodiment of FIG. 1A, can 10 includes a plurality of circumferential beads 40 formed in sidewall 16. Generally, each bead 40 is a radially outwardly extending curved surface that extends radially outward relative to sidewall 16. In various embodiments, can 10 includes at least two circumferential beads including at least one bead located in center portion 24 and at least one bead located in upper portion 26 and/or in lower portion 28. Beads 40 act to strengthen sidewall 16 against radial loads that may occur due to the pressure differential between the interior of can 10 and atmospheric pressure and/or by the grip of a person holding can 10. In various embodiments, can 10 is configured to hold contents at an internal pressure differential of at least 28 pounds/square inch (gauge) or “psig,” and in another embodiment, can 10 is configured to hold contents at an internal pressure differential of at least 22 psig. In other embodiments, can 10 is filled with food located with the internal cavity of can 10 and the can is sealed and has an internal pressure differential of at least 22 psig, in one embodiment, and at least 28 psig, in another embodiment. In these embodiments, beads 40 are configured to strength non-cylindrical sidewall 16 against the radial inward force that results from the internal pressure differential.

In various embodiments, sidewall 16 is made from metal of various thicknesses, and beads 40 are selected to strength non-cylindrical sidewall 16 against the radial inward force that results from the internal pressure differential for the various thicknesses. According to various exemplary embodiments, sidewall 16 is formed from steel (e.g., tinplate, stainless steel, food grade tinplate, etc.) having a working gauge range of about 0.003 inches thick to about 0.012 inches thick, specifically of about 0.005 inches thick to about 0.009 inches thick, and more specifically, of about 0.006 inches thick to about 0.008 inches thick. In one specific embodiment, sidewall 16 is formed from steel having a working gauge of 0.007 inches plus or minus 0.0005 inches.

In various embodiments, for example as shown in FIGS. 1A and 2, can 10 includes a bead panel 42. Bead panel 42 includes a plurality of continuous, radially outwardly extending beads 40. In various embodiments, bead panel 42 is formed in the material of center portion 24, upper portion 26 and lower portion 28, such that bead panel 42 is a continuous beaded sidewall section extending from the non-cylindrical upper portion 26 through cylindrical center portion 24 and into non-cylindrical lower portion 28. Thus, bead panel 42 includes beads 40 located on the cylindrical portion (e.g., center portion 24) and on the non-cylindrical or angled portions (e.g., upper portion 26 and lower portion 28) of sidewall 16.

Referring to FIG. 3, a detailed view of center portion 24 and upper portion 26 of sidewall 16 is shown. As shown in FIG. 3, a radially inwardly extending curved bead 44 is located between each adjacent outwardly extending bead 40 in bead panel 42. This configuration gives bead panel 42 a pattern of alternating outwardly extending beads 40 and inwardly extending surfaces, and in this embodiment, each outwardly extending bead 40 is contiguous with each adjacent inwardly extending bead 44. In the embodiment shown, the outer surface of each bead 40 is a continuously curved surface that is concave relative to the longitudinal axis 34 of can 10, and the outer surface of each inward bead 44 is a continuously curved surface that is convex relative to longitudinal axis 34. As shown in FIG. 1A, each inwardly extending curved bead 44 extends around the circumference of sidewall 16.

In various embodiments, the shape (e.g., the depth, height, radius of curvature, the profile outline, etc.) of circumferential beads 40 varies at different axial positions along sidewall 16. In one embodiment as shown in FIG. 2, the shape of at least one bead 40 located in upper sidewall portion 26 is different from the shape of at least one bead located in center portion 24, and the shape of at least one bead 40 located in lower sidewall portion 28 is different from the shape of at least one bead located in center portion 24. In various embodiments, the shape of beads 40 is a function of the diameter of sidewall 16 in which the beads are located. For example, in the embodiment shown in FIGS. 2 and 3, the shape of beads 40 is a function of the diameter of sidewall 16 at the location of the bead.

In various embodiments, the depth of each bead 40 (e.g., distance between the outermost point of an outward bead 40 and the inner most surface of the adjacent inwardly curved bead 44 measured in the direction perpendicular to longitudinal axis 34) is a function of the diameter of sidewall 16 in which the bead 40 is formed. Thus, in the embodiment shown in FIG. 2, the depth of beads 40 located in upper sidewall portion 26 is different than the depth of the beads 40 located in center sidewall portion 24, and the depth of beads 40 located in lower sidewall portion 28 is different than the depth of the beads 40 located in center sidewall portion 24. In general as shown in FIG. 2, the depth of at least one bead 40 in upper sidewall portion 26 is less than the depth of at least one bead 40 formed in center portion 24, and the depth of at least one bead 40 in lower sidewall portion 28 is less than the depth of at least one bead 40 formed in center portion 24.

In the embodiment shown in FIG. 2, both upper portion 26 and lower portion 28 are tapered sections having diameters that increase as the distance from the axial center point of can 10 increases. In this embodiment, the depth of beads 40 in both upper portion 26 and lower portion 28 decrease as the axial distance from the center point increases. Further, the depth of beads 40 in both upper portion 26 and lower portion 28 decrease as the axial distance to upper end wall 12 and lower end wall 14 decreases, respectively. In these embodiments, the depth of beads 40 decrease as the diameter of sidewall 16 at the location of the bead increases.

In various embodiments, the pitch of each bead 40 (e.g., the distance between the outer most points of adjacent outward beads measured in the direction parallel to longitudinal axis 34) is a function of the diameter of sidewall 16 in which the bead 40 is formed. Thus, in the embodiment shown in FIG. 2, the pitch of beads 40 located in upper sidewall portion 26 is different than the pitch of the beads 40 located in center sidewall portion 24, and the pitch of beads 40 located in lower sidewall portion 28 is different than the pitch of the beads 40 located in center sidewall portion 24.

Referring to FIG. 3, an enlarged view of center portion 24 and upper portion 26 is shown according to an exemplary embodiment. By way of example, outward bead 50 is a bead located in center portion 24 and outward bead 52 is a bead located in upper portion 26. Bead 50 has a bead depth BD1, and bead 52 has a bead depth BD2. In one embodiment, depth BD1 of bead 50 is the same before and after sidewall 16 is shaped into the non-cylindrical shape shown in FIG. 2, and depth BD2 of bead 52 is less than the depth of bead 52 before shaping.

FIG. 3 shows a portion of a non-cylindrical sidewall in which the shape of the bead 40 varies based upon the diameter of the sidewall 16 at the location of the bead 40 according to an exemplary embodiment. In various embodiments, BD2 is between 1% and 40% less than BD1, specifically between 5% and 30% less than BD1 and more specifically is between 5% less and 20% less than BD1. In specific embodiments, BD2 is between 10% and 20% less than BD1 and more specifically is between 13% and 16% of BD1.

In various embodiments, BD1 is between 0.015 and 0.035 inches, specifically between 0.020 and 0.030 inches and more specifically is between 0.023 and 0.027 inches. In various embodiments, BD2 is between 0.011 and 0.031 inches, specifically is between 0.016 and 0.026 inches and more specifically is between 0.019 and 0.023 inches.

In various embodiments, BD2 of bead 52 is different before and after shaping a metal tube into a non-cylindrical sidewall 16. For example, in various embodiments, before shaping of upper portion 26 into the non-cylindrical shape, BD2 is between 0.015 and 0.035 inches, specifically between 0.020 and 0.030 inches and more specifically is between 0.023 and 0.027 inches, and, in these embodiments, after shaping, BD2 is between 0.011 and 0.031 inches, specifically is between 0.016 and 0.026 inches and more specifically is between 0.019 and 0.023 inches.

As noted above, bead pitch also varies based on the diameter of the sidewall 16 where the beads are located. By way of example, bead panel 42 includes an upper most outward bead 54 located in upper portion 26 at the uppermost end of bead panel 42. Bead 50 has a bead pitch BP1, and bead 54 has a bead pitch BP2. In one embodiment, bead pitch BP1 of bead 50 is the same before and after sidewall 16 is shaped into the non-cylindrical shape shown in FIG. 2, and pitch BP2 of bead 54 is greater than the pitch of bead 54 before shaping. In various embodiments, BP2 is between 0.5% and 15% greater than BP1, specifically between 0.5% and 10% greater than BP1 and more specifically is between 1% and 5% greater than BP1. For the specific embodiment shown in FIG. 3, BP2 is about 3.5% greater than BP1 (plus or minus 0.5%).

In various embodiments, BP1 is between 0.05 and 0.25 inches, specifically between 0.09 and 0.20 inches and more specifically is between 0.12 and 0.16 inches. In one specific embodiment, BP1 is between 0.139 and 0.140 inches. In various embodiments, BP2 is between 0.05 and 0.25 inches, specifically between 0.09 and 0.20 inches and more specifically is between 0.12 and 0.16 inches. In one specific embodiment, BP2 is between 0.140 and 0.141 inches. In various embodiments, BP2 is between 0.139 and 0.140 inches prior to shaping of upper portion 26 into the non-cylindrical shape, and BP2 is between 0.140 and 0.0141 inches after shaping of upper portion 26 into the non-cylindrical shape. It should be noted that corresponding beads in lower portion 28 may be similarly shaped as beads 52 and 54 and the measurements, relative sizing and ratios discussed herein also relate to beads in lower portion 28.

Referring to FIG. 2, in one embodiment, can 10 includes a bead panel 42 including 18 outwardly extending beads 40. Further, bead panel 42 extends more than 50% of the axial length of sidewall 16. However, in other embodiments, can 10 may include differently shaped bead panels. For example, as shown in FIG. 4, can 10 includes a bead panel 60 that includes eight radially outward extending beads 62, and, as shown in FIG. 5, can 10 includes a bead panel 70 that includes six radially outward extending beads 72. In various embodiments, the bead panel of can 10 may include between 4 and 24 beads, between 6 and 18 beads or between 8 and 18 beads.

Thus in the various embodiments, can 10 may include one or more outwardly extending beads on upper portion 26, one or more outwardly extending beads on center portion 24 and one or more outwardly extending beads on lower portion 28. In some embodiments, can 10 may include an unbeaded sidewall section between the beads of upper portion 26 and center portion 24, and can 10 may include an unbeaded sidewall section between the beads of lower portion 28 and center portion 24. In various embodiments, can 10 may include a bead panel that extends more than 25% of the axial length of sidewall 16, and in other embodiments, can 10 may include a bead panel that extends more than 30% of the axial length of sidewall 16. In various embodiments, can 10 may include a bead panel that accounts for between 25% to 75% of the axial length of sidewall 16, and in other embodiments, can 10 may include a bead panel that accounts for between 30% to 60% of the axial length of sidewall 16.

Referring back to FIG. 1A, sidewall 16 of can 10 includes an alternating series of vertically positioned bands or facets. As shown, for example in FIG. 1A, can 10 includes inwardly curved facets 46 spaced between outwardly curved facets 48. Inwardly curved facets 46 and outwardly curved facets 48 are evenly spaced around sidewall 16 and extend substantially parallel to the vertical axis of can 10. In one embodiment, can 10 includes ten inwardly curved facets 46 and nine outwardly curved facets 48. In one embodiment, facets 46 and facets 48 are caused by an expanding mandrel which expands within sidewall 16 to form the non-cylindrical shape of sidewall 16.

Referring to FIG. 6, a method 100 of making can 10 is shown according to an exemplary embodiment. At step 102, a rectangular piece of metal 104 is provided. At step 106, a metal tube 108 is provided. In one embodiment, tube 108 is formed by rolling rectangular piece of metal 104 such that the lateral edges 110 and 112 are adjacent to each other and are welded together creating a welded seam 114 that extends vertically the axial length of tube 108. At step 116, tube 108 under goes a pre-shaping step in which an upper flared section 118 and a lower flared section 120 are formed such that tube 108 includes a substantially cylindrical sidewall 122 located between the upper and lower flared sections.

At step 124, beads 126 are formed in the cylindrical sidewall 122. In one embodiment, beads 126 are formed such that each bead has substantially the same bead depth and bead pitch as the other beads formed in cylindrical sidewall 122. At step 130, tube 108 is shaped to form non-cylindrical sidewall 16 including center portion 24, upper portion 26 and lower portion 28, discussed above. Thus, the shaping step that forms the non-cylindrical sidewall 16 occurs after beads 126 are formed into the material that becomes sidewall 16.

In one embodiment, non-cylindrical sidewall 16 is formed using an expanding mandrel. Profile 132 shown in FIG. 7 is the general profile shape of an embodiment of sidewall 16 prior to bead formation. In one embodiment, an expanding mandrel may be expanded from a collapsed configuration to an expanded configuration to generally form a can sidewall 16 having the profile 132 shown in FIG. 7. In such an embodiment, the expanded configuration of the mandrel is shaped to match the desired shape of non-cylindrical sidewall 16, and the mandrel is expanded following insertion into the sidewall. In other embodiments, other shaping tools may be used to shape sidewall 16 into the desired shape.

At step 140, upper flange 30 and lower flange 32 are formed at the upper and lower ends of sidewall 16. At step 142, lower end wall 14 is coupled to the lower flange 32 via double seam 22. A detailed view of double seam 22 is shown in FIG. 8 and shows the seam formed from interlocked and crimped portions of material of both sidewall 16 and end wall 14. Following attachment of lower end wall 14, can 10 may be stored or shipped along with a separate upper can end 12. Once can 10 is filled, for example filled with food at a packaging facility, upper end wall 12 is attached to sidewall 16 via double seam 22 hermetically sealing the food within can 10.

Referring to FIG. 9, a cross-sectional view of can 10, having bead panel 60 as shown in FIG. 4, is depicted according to an exemplary embodiment. FIG. 10 shows an enlarged view of bead panel 60. As shown in FIG. 9 and FIG. 10, bead panel 60 includes eight radially outwardly curved beads 62 and nine radially inwardly curved beads 63. Similar to the embodiment discussed above regarding FIG. 2, beads 62 and beads 63 extend through the center portion of the can sidewall onto the expanded upper and lower sidewall portions, and the shape, bead height and/or bead depth of beads 62 and beads 63 may vary based on the diameter of the sidewall at the location of the bead, providing increased strength to the can sidewall.

Referring to FIG. 10, bead 150 is a centrally located bead located in center sidewall portion 24 and has a bead depth BD1 as discussed above. Bead 152 is an inwardly curved bead formed in upper sidewall portion 26, and bead 154 is an inwardly curved bead formed in lower sidewall portion 28. Bead 152 has a bead depth BD3, which is the radial distance measured between the radially innermost point of bead 152 and the upper edge of bead panel 60. Bead 154 has a bead depth BD4, which is the radial distance measured between the radially innermost point of bead 154 and the lower edge of bead panel 60.

In various embodiments, BD3 is between 10% and 60% less than BD1, specifically between 20% and 50% less than BD1 and more specifically is between 25% less and 40% less than BD1. In specific embodiments, BD3 is between 30% and 40% less than BD1 and more specifically is between 30% and 36% less than BD1.

In various embodiments, BD1 is between 0.015 and 0.035 inches, specifically between 0.020 and 0.030 inches and more specifically is between 0.023 and 0.027 inches. In various embodiments, BD3 is between 0.006 and 0.031 inches, specifically is between 0.010 and 0.020 inches and more specifically is between 0.013 and 0.019 inches. In a specific embodiment, BD3 is about 0.016 inches.

In various embodiments, BD3 of bead 152 is different before and after shaping a metal tube into a non-cylindrical sidewall 16. For example, in various embodiments, before shaping of upper portion 26 into the non-cylindrical shape, BD3 is between 0.015 and 0.035 inches, specifically between 0.020 and 0.030 inches and more specifically is between 0.023 and 0.027 inches, and, in these embodiments, after shaping, BD3 is between 0.006 and 0.031 inches, specifically is between 0.010 and 0.020 inches and more specifically is between 0.013 and 0.019 inches. In a specific embodiment, BD3 is about 0.016 inches after shaping.

In various embodiments, BD4 is between 20% and 70% less than BD1, specifically between 30% and 60% less than BD1 and more specifically is between 35% and 55% less than BD1. In specific embodiments, BD3 is between 40% and 50% less than BD1 and more specifically is between 43% and 46% less than BD1. In various embodiments, BD4 is between 0.003 and 0.023 inches, specifically is between 0.07 and 0.019 inches and more specifically is between 0.010 and 0.016 inches. In a specific embodiment, BD4 is about 0.013 inches.

In various embodiments, BD4 of bead 154 is different before and after shaping a metal tube into a non-cylindrical sidewall 16. For example, in various embodiments, before shaping of lower portion 28 into the non-cylindrical shape, BD4 is between 0.015 and 0.035 inches, specifically between 0.020 and 0.030 inches and more specifically is between 0.023 and 0.027 inches, and, in these embodiments, after shaping, BD4 is between 0.003 and 0.023 inches, specifically is between 0.07 and 0.019 inches and more specifically is between 0.010 and 0.016 inches. In a specific embodiment, BD4 is about 0.013 inches, after shaping.

As shown in FIG. 9, bead panel 60 extends at least 20% but less than 80% of the axial length of the sidewall of can 10. In one embodiment, bead panel 60 accounts between 30% and 40% of the axial length of the sidewall of can 10, and more specifically accounts for about 37% of the axial length of the sidewall of can 10. As noted above, bead panel 60 extends through center portion 24 and onto the expanded upper and lower sections of the can sidewall.

Referring to FIGS. 11 and 12, a container, shown as metal can 200, is depicted according to an exemplary embodiment. Can 200 is similar to can 10 with certain specific differences discussed below. Can 200 includes a metal sidewall 202. Sidewall 202 is coupled to upper and lower can ends via hermetic seams 230 and 232 as discussed above. Sidewall 202 includes a center portion 204, an upper portion 206 and a lower portion 208. Upper portion 206 extends from the upper edge of center portion 204 to the lower edged of seam 230. Lower portion 208 extends from the lower edge of center portion 204 to the upper edge of seam 232.

Upper portion 206 extends upward toward the upper end of can 200 and radially outward from center portion 204. Thus, the diameter of upper portion 206 increases as the distance from center portion 204 increases until a maximum upper diameter, D6, is reached. At the maximum upper diameter, upper portion 206 extends upward toward the upper end of can 200 and radially inward to join the vertical sidewall section immediately adjacent the upper can end. Thus, the diameter of upper portion 206, above maximum diameter D6, decreases as the distance from the maximum upper diameter D6 increases and as the distance to the upper end of can 200 decreases.

Lower portion 208 extends downward toward the lower end of can 200 and radially outward from center portion 204. Thus, the diameter of lower portion 208 increases as the distance from center portion 204 increases until a maximum lower diameter, D7, is reached. At the maximum lower diameter D7, lower portions 207 extends downward toward the lower end of can 200 and radially inward to join the vertical sidewall section immediately adjacent the lower can end. Thus, the diameter of lower portion 208, below maximum lower diameter D7, decreases as the distance from the maximum lower diameter D7 increases and as the distance to the lower end of can 200 decreases.

As shown in FIG. 11, upper portion 206 and lower portion 208 include radially outwardly extending curved sections at D6 and D7, respectively. The outer surface of the curved sections are concave curved relative to the longitudinal axis of can 200 and are convex curved surfaces relative to the exterior of can 200. In one embodiment, as shown, D6 and D7 are substantially the same as each other. In another embodiment, D6 is greater than D7 such that upper portion 206 extends radially outward beyond D7. In another embodiment D7 is greater than D6 such that the lower portion 208 extends radially outward beyond D6.

Can 200 includes a bead panel 210. Similar to the bead panel of can 10 discussed above, bead panel 210 acts to strengthen sidewall 202 against radially directed forces. Referring to FIG. 12, a detailed view of bead panel 210 is shown. As shown, bead panel 210 includes five radially inwardly extending beads and four radially outwardly extending beads. Specifically, bead panel 210 includes at least three inwardly extending beads, 212, 214 and 216, located in the substantially cylindrical, center portion 204. Bead panel 210 also includes an upper radially inward extending bead 218 and a lower radially inward extending bead 220. Bead 218 is the upper most inward bead of bead panel 210 and is located on the lower section of upper sidewall portion 206. Bead 220 is the lowermost inward bead of bead panel 210 and is located on the upper portion of lower sidewall portion 208.

Bead panel 210 also includes a series of outwardly extending beads 222. Outwardly extending beads 222 are located between adjacent inwardly extending beads as discussed above. Thus, each outwardly extending bead 222 transitions into an inwardly extending bead located above the outwardly extending bead and also transitions into an inwardly extending bead located below the outwardly extending bead. Further, both the inwardly extending beads and the outwardly extending beads of bead panel 210 are circumferential beads that extend around the entire circumference of can 210. Further the beads are positioned such that they are substantially parallel with the plane of the upper and lower can ends.

As shown in FIG. 12, centrally located inward bead 216 has a bead depth BD5. In various embodiments, BD5 is between 0.005 and 0.025 inches, specifically between 0.010 and 0.020 inches and more specifically between 0.010 and 0.016 inches. In various specific embodiments, BD5 is between 0.011 and 0.016 inches, more specifically is between 0.013 and 0.014 inches. In the embodiment shown, centrally located beads 212, 214 and 216 have substantially the same bead depth as each other, which may be any of the bead depths BD5 discussed above.

Upper most inward bead 218 has a bead depth BD6. BD6 is the radial distance measured between the innermost point of bead 218 and the lower edge of upper portion 206. In various embodiments, BD6 is between 0.001 and 0.020 inches, more specifically BD6 is between 0.005 and 0.015 inches and more specifically between 0.009 inches and 0.013 inches. In various specific embodiments, BD6 is between 0.010 and 0.013 inches, and more specifically is between 0.011 and 0.012 inches. In one embodiment, the bead depth of lower most bead 220 (i.e., the radial distance measured between the innermost point of bead 220 and the upper edge of lower portion 204) is the same as BD6.

In various embodiments, BD6 is less than BD5, and BD5 and BD6 may be any combination of bead depths or ranges of bead depths recited herein. For example, in various embodiments, BD6 is less than BD5, and BD5 is between 0.005 and 0.025 inches, and BD6 is between 0.001 and 0.020 inches. In a more specific embodiment, BD6 is less than BD5, and BD5 is between 0.010 and 0.020 inches, and BD6 is between 0.005 and 0.015 inches. In a yet more specific embodiment, BD6 is less than BD5, and BD5 is between 0.011 and 0.016 inches, and BD6 is between 0.009 inches and 0.013. In a particular embodiment, BD6 is less than BD5, and BD5 is between 0.013 and 0.014 inches, and BD6 is between 0.011 and 0.012 inches.

Thus, similar to can 10, the depth of the beads formed in the sidewall of can 200 decrease as the diameter of the sidewall in which the beads are located increases. For example, as shown, BD6 is less than BD5, because the diameter of sidewall 202 is greater at the lower end of upper portion 206 than it is in the middle of center portion 204. In one embodiment, BD6 is between 10% and 30% less than BD5, specifically is between 15% and 25% less than BD5 and more specifically between 15% and 20% less than BD5. In various specific embodiments, BD6 is between 17% and 20% less than BD5 and more specifically is between 18.5% and 19.5% less than BD6.

Bead panel 210 also has a bead panel height, BH. In various embodiments, BH is between 0.7 inches and 1.1 inches, specifically is between 0.8 and 1.0 inches, and more specifically between 0.90 and 0.95 inches. In one specific embodiment, BH is between 0.92 and 0.94 inches and more specifically is 0.93 inches. In various embodiments, BH is between 10% and 30% of the total height of can 200, specifically between 15% and 25% of the total height of can 200, and more specifically between 19% and 23% of the total height of can 200. In various specific embodiments, BH is between 20% and 22% of the of the total height of can 200 and more specifically is about 21% of the total height of can 200.

According to exemplary embodiments, the containers, and specifically the container sidewalls, discussed herein are formed from metal, and specifically may be formed from, stainless steel, tin-coated steel, aluminum, etc. In some embodiments, the containers discussed herein are formed from aluminum and the can ends are formed from tin-coated steel. In some embodiments, the sidewall of the container is formed from a metal material and other metals or materials (e.g., polymers, high-temperature plastic, thermoplastics, cardboard, ceramic, etc.) are used to form the end walls of the container.

Containers discussed herein may include containers of any style, shape, size, etc. For example, the containers discussed herein may be shaped such that cross-sections taken perpendicular to the longitudinal axis of the container are generally circular. However, in other embodiments the sidewall of the containers discussed herein may be shaped in a variety of ways (e.g., having other non-polygonal cross-sections, as a rectangular prism, a polygonal prism, any number of irregular shapes, etc.) as may be desirable for different applications or aesthetic reasons. In various embodiments, the sidewall of can 10 may include one or more axially extending sidewall sections that are curved radially inwardly or outwardly such that the diameter of the can is different at different places along the axial length of the can, and such curved sections may be smooth continuous curved sections. In one embodiment, can 10 may be hourglass shaped. Can 10 may be of various sizes (e.g., 3 oz., 8 oz., 12 oz., 15 oz., 28 oz, etc.) as desired for a particular application.

Further, a container may include a container end (e.g., a closure, lid, cap, cover, top, end, can end, sanitary end, “pop-top”, “pull top”, convenience end, convenience lid, pull-off end, easy open end, “EZO” end, etc.). The container end may be any element that allows the container to be sealed such that the container is capable of maintaining a hermetic seal. In an exemplary embodiment, the upper can end may be an “EZO” convenience end, sold under the trademark “Quick Top” by Silgan Containers Corp.

The upper and lower can ends discussed above are shown coupled to the can body via a “double seam” formed from the interlocked portions of material of the can sidewall and the can end. However, in other embodiments, the can ends discussed herein may be coupled to the sidewall via other mechanisms. For example, can ends may be coupled to the sidewall via welds or solders. As shown above, the containers discussed herein are three-piece cans having an upper can end, a lower can end and a sidewall each formed from a separate piece of material. However, in other embodiments, a two-piece can (i.e., a can including a sidewall and an end wall that are integrally formed and a separate can end component joined to the sidewall via a double seam) may be provided with an internal strainer as discussed herein.

In various embodiments, the upper can end may be a closure or lid attached to the body sidewall mechanically (e.g., snap on/off closures, twist on/off closures, tamper-proof closures, snap on/twist off closures, etc.). In another embodiment, the upper can end may be coupled to the container body via an internal pressure differential. The container end may be made of metals, such as steel or aluminum, metal foil, plastics, composites, or combinations of these materials. In various embodiments, the can ends, double seams, and sidewall of the container are adapted to maintain a hermetic seal after the container is filled and sealed.

The containers discussed herein may be used to hold perishable materials (e.g., food, drink, pet food, milk-based products, etc.). It should be understood that the phrase “food” used to describe various embodiments of this disclosure may refer to dry food, moist food, powder, liquid, or any other drinkable or edible material, regardless of nutritional value. In other embodiments, the containers discussed herein may be used to hold non-perishable materials or non-food materials. In various embodiments, the containers discussed herein may contain a product that is packed in liquid that is drained from the product prior to use. For example, the containers discussed herein may contain vegetables, pasta or meats packed in a liquid such as water, brine, or oil.

During certain processes, containers are filled with hot, pre-cooked food then sealed for later consumption, commonly referred to as a “hot fill process.” As the contents of the container cool, the pressure within the sealed container decreases such that there is a pressure differential (i.e., internal vacuum) between the interior of the container and the exterior environment. This pressure difference, results in an inwardly directed force being exerted on the sidewall of the container and on the end walls of the container. In embodiments using a vacuum attached closure, the resulting pressure differential may partially or completely secure the closure to the body of the container. During other processes, containers are filled with uncooked food and are then sealed. The food is then cooked to the point of being commercially sterilized or “shelf stable” while in the sealed container. During such a process, the required heat and pressure may be delivered by a pressurized heating device or retort.

According to various exemplary embodiments, the inner surfaces of the upper and lower can ends and the sidewall may include a liner (e.g., an insert, coating, lining, a protective coating, sealant, etc.). The protective coating acts to protect the material of the container from degradation that may be caused by the contents of the container. In an exemplary embodiment, the protective coating may be a coating that may be applied via spraying or any other suitable method. Different coatings may be provided for different food applications. For example, the liner or coating may be selected to protect the material of the container from acidic contents, such as carbonated beverages, tomatoes, tomato pastes/sauces, etc. The coating material may be a vinyl, polyester, epoxy, EVOH and/or other suitable lining material or spray. The interior surfaces of the container ends may also be coated with a protective coating as described above.

Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only. The construction and arrangements, shown in the various exemplary embodiments, are illustrative only. Although only a few embodiments have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. Some elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. The order or sequence of any process, logical algorithm, or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present invention.

While the current application recites particular combinations of features in the claims appended hereto, various embodiments of the invention relate to any combination of any of the features described herein whether or not such combination is currently claimed, and any such combination of features may be claimed in this or future applications. Any of the features, elements, or components of any of the exemplary embodiments discussed above may be used alone or in combination with any of the features, elements, or components of any of the other embodiments discussed above.

In various exemplary embodiments, the relative dimensions, including angles, lengths and radii, as shown in the Figures are to scale. Actual measurements of the Figures will disclose relative dimensions, angles and proportions of the various exemplary embodiments. Various exemplary embodiments extend to various ranges around the absolute and relative dimensions, angles and proportions that may be determined from the Figures. Various exemplary embodiments include any combination of one or more relative dimensions or angles that may be determined from the Figures. Further, actual dimensions not expressly set out in this description can be determined by using the ratios of dimensions measured in the Figures in combination with the express dimensions set out in this description.

Claims

1. A method of forming a beaded metal food can comprising: providing a cylindrical metal tube having an outer surface, an upper edge defining an upper opening and a lower edge defining a lower opening;forming a plurality of circumferential beads defining a bead panel in the cylindrical metal tube, wherein the bead panel comprises a continuous series of radially outwardly extending curved surfaces and radially inwardly extending curved surfaces positioned between each radially outwardly extending curved surface, each radially outwardly extending curved surface and each radially inwardly extending curved surface extending circumferentially around the metal tube, wherein the radially outwardly extending curved surfaces and the radially inwardly extending curved surface are defined in the outer surface of the metal tube;shaping the cylindrical metal tube to form a non-cylindrical metal sidewall, after forming the bead panel, the non-cylindrical sidewall comprising: a center section having a first diameter;an upper sidewall section located above the center section having a second diameter greater than the first diameter, the upper sidewall section extending radially outward relative to the center section to provide the transition from the first diameter to the second diameter; anda lower sidewall section located below the center section having a third diameter greater than the first diameter, the lower sidewall section extending radially outward relative to the center section to provide the transition from the first diameter to the third diameter; andcoupling a can end to at least one of the upper edge and the lower edge of the tube.

2. The method of claim 1 wherein shaping includes shaping at least a portion of the metal tube including one of the curved surfaces of the bead panel.

3. The method of claim 1 wherein shaping includes inserting an expanding mandrel into the cylindrical metal tube and expanding the mandrel against an inner surface of the cylindrical metal tube to form the non-cylindrical metal sidewall, and wherein the center section is located at the axial center point of the non-cylindrical metal sidewall.

4. The method of claim 3 wherein at least one of the curved surfaces of the bead panel is formed in each of the center section, the upper sidewall section and the lower sidewall section.

5. The method of claim 4 wherein the bead panel encompasses at least 10% of the axial length of the sidewall.

6. The method of claim 1 further comprising: providing a rectangular piece of metal having left and right lateral edges;rolling the rectangular piece of metal such that the left and right lateral edges are adjacent to each other; andwelding the left and right lateral edges together to form the cylindrical metal tube, wherein the tube includes an axially extending weld that extends from the upper edge to the lower edge.

7. The method of claim 4 wherein an uppermost radially inward extending curved surface of the bead panel is located in the upper sidewall section, wherein the bead panel extends through the center section to a lowermost radially inward extending curved surface of the bead panel located in the lower sidewall section.

8. The method of claim 4 wherein each of the plurality of the circumferential beads of the bead panel has a bead depth, wherein the depth of at least one circumferential bead of the bead panel located in the upper sidewall section is less than the depth of at least one circumferential bead of the bead panel located in the center section and the depth of at least one circumferential bead of the bead panel located in the lower sidewall section is less than the depth of at least one circumferential bead of the bead panel located in the center section.

9. The method of claim 8 wherein the depth of at least one circumferential bead of the bead panel located in the upper sidewall section is between 10%-30% less than the depth of at least one circumferential bead of the bead panel located in the center section.

10. The method of claim 8 wherein the bead depths of the circumferential beads of the bead panel decrease as the diameter of the sidewall in which the bead is formed increases, wherein the metal tube is formed from steel having a thickness between 0.0065 inches and 0.008 inches.

11. The method of claim 7 wherein each of the plurality of the circumferential beads of the bead panel has a shape, wherein the shape of at least one circumferential bead of the bead panel located in the upper sidewall section is different from the shape of at least one circumferential bead of the bead panel located in the center section and the shape of at least one circumferential bead of the bead panel located in the lower sidewall section is different from the shape of at least one circumferential bead of the bead panel located in the center section.

12. The method of claim 1 further comprising forming a first flared section in the cylindrical metal tube adjacent the upper edge and forming a second flared section in the cylindrical metal tube adjacent the lower edge, wherein both the first flared section and the second flared section are formed before forming of the plurality of circumferential beads.

13. A method of forming a beaded metal food can comprising: providing a metal tube having an upper edge defining an upper opening, a lower edge defining a lower opening and a cylindrical portion located between the upper edge and the lower edge;forming a plurality of circumferential beads in the cylindrical portion of the metal tube, wherein each circumferential bead includes a radially inwardly extending curved surface positioned along an outer surface of the metal tube;shaping the beaded cylindrical portion of metal tube after formation of the plurality of circumferential beads to form a beaded non-cylindrical metal sidewall section, the non-cylindrical sidewall section comprising: a center section having a first diameter;an upper sidewall section located above the center section having a second diameter greater than the first diameter, the upper sidewall section extending radially outward relative to the center section to provide the transition from the first diameter to the second diameter; anda lower sidewall section located below the center section having a third diameter greater than the first diameter, the lower sidewall section extending radially outward relative to the center section to provide the transition from the first diameter to the third diameter, wherein the non-cylindrical metal sidewall section includes the plurality of circumferential beads following shaping to form the non-cylindrical metal sidewall section; andcoupling a can end to at least one of the upper opening and the lower opening of the tube.

14. The method of claim 13 further comprising: providing a rectangular piece of metal having left and right lateral edges;rolling the rectangular piece of metal such that the left and right lateral edges are adjacent to each other; andwelding the left and right lateral edges together to form the metal tube, wherein the tube includes an axially extending weld that extends from the upper edge to the lower edge.

15. The method of claim 14 further comprising forming a first flared section in the metal tube adjacent the upper edge and forming a second flared section in the metal tube adjacent the lower edge, wherein the cylindrical portion is located between the first flared section and the second flared section, wherein both the first flared section and the second flared section are formed before forming of the plurality of circumferential beads.

16. The method of claim 13 wherein the forming of the plurality of circumferential beads is forming a bead panel comprising a continuous series of radially outward extending curved surfaces and radially inward extending curved surfaces positioned between each radially outward extending curved surface, each radially outward extending curved surface and each radially inward extending curved surface extending circumferentially around the cylindrical portion of the metal tube.

17. The method of claim 16 wherein each bead of the bead panel has the same bead depth prior to shaping to form the bead non-cylindrical metal sidewall section.

18. The method claim 17 wherein shaping includes inserting an expanding mandrel into the metal tube and expanding the mandrel against an inner surface of the cylindrical portion of the metal tube to form the beaded non-cylindrical metal sidewall section, wherein the center section is located at the axial center point of the non-cylindrical metal sidewall.

19. The method of claim 18 further comprising: forming a first flange adjacent the upper edge of the metal tube;forming a second flange adjacent the lower edge of the metal tube;wherein the can end is coupled to at least one of the upper opening and the lower opening of the tube by coupling the can end to at least one of the first flange and the second flange.

20. A method of forming a beaded metal food can comprising: providing a metal tube having an outer surface, an upper edge defining an upper opening, a lower edge defining a lower opening and a cylindrical portion located between the upper edge and the lower edge;forming a bead panel in the cylindrical portion of the metal tube, wherein the bead panel comprises a continuous series of radially outward extending curved surfaces and radially inward extending curved surfaces positioned between each radially outward extending curved surface, each radially outward extending curved surface and each radially inward extending curved surface extending circumferentially around the cylindrical portion of the metal tube, wherein the radially outwardly extending curved surfaces and the radially inwardly extending curved surface are defined in the outer surface of the metal tube;shaping the cylindrical portion of the metal tube after formation of the bead panel to form a beaded non-cylindrical metal sidewall section, wherein the non-cylindrical sidewall extends concavely along at least a portion of the length of the non-cylindrical sidewall;forming a first flange adjacent the upper edge of the metal tube;forming a second flange adjacent the lower edge of the metal tube; andcoupling a can end to at least one of the first flange and the second flange.