Full-open convenience-feature sheet metal can

One-piece sheet metal can body and end closure structure for assembly of a two-piece can with full-panel convenience feature and protection for residual scoreline metal edge after opening; a tamper-proof non-breakable container with full access for various types of food is provided. A stepped-flange rim on the can body and a U-shaped groove in the end panel, for submerging the scoreline, shield severed edge metal.

This invention is concerned with one-piece sheet metal can bodies, closure 
structures for two-piece sheet metal cans, convenience features with 
severed edge metal protection and corresponding fabrication methods. 
A typical application for the contributions of the invention would be baby 
food containers. Sheet metal threaded caps have been widely and 
advantageously used with glass jars in the manufacture of such containers. 
Several desirable features for baby food containers have presented 
problems of long standing which tended to block further use of sheet metal 
in the manufacture of such containers. However, significant improvements 
in fabricating methods and structural features as taught herein enable 
sheet metal usage throughout such containers while providing the access 
required for the different types of baby foods, and desired easy-open 
features. 
As part of the present invention, measures capable of providing desired 
versatility in handling semi-fluid to semi-solid contents were analyzed 
along with prior art problems and limitations on convenience features. As 
a result of the concepts devised, a tamper-proof, rigid, non-breakable, 
long shelf-life storage container for foods is provided along with 
full-panel pull-out convenience features for ready access to and removal 
of semi-solid foods, stable stacking provisions for sealed cans, and 
severed metal edge protection features after opening. These features are 
provided economically while eliminating disadvantages which have been 
associated with the side wall seam of a three-piece can.

That the assembled sheet metal can 20 of FIG. 1 utilizes a cup-shaped can 
body 21 which is free of seams is an important contribution considering 
the convenience and safety features made available by the invention. 
Portions of this can body, such as its unitary end wall and side wall, can 
be formed by draw-redraw techniques as disclosed in copending U.S. 
application Ser. No. 712,238, filed Mar. 15, 1985, entitled "Drawn Can 
Body Methods, Apparatus and Products" (which is included herein by 
reference). However, in addition, a stepped-flange rim 22 (FIG. 6) is 
formed at its open end. 
Stepped-flange rim 22, side wall 24 and bottom end wall 25 are unitary and 
each is symmetrically located with respect to central longitudinal axis 
26. 
A significant contribution to the food container art is the provision of a 
convenience-feature opening having a diameter at least equal to that of 
the side wall main body. This facilitates removal of non-pourable contents 
(for example semi-solid comestibles) while combining easy-open and edge 
protection features. 
In the embodiment of FIG. 1, the main body portion of the side wall is of 
uniform diameter throughout the height from unitary end wall 25 to 
stepped-flange rim 22. 
The closure structure 28 of FIG. 2 presents peripheral flange metal 29 
which is joined with peripheral flange metal of can body 21 to form a 
chime seam 30 (FIG. 1); conventional double-seam chime practice can be 
utilized. 
An elongated tab opener 32 (FIGS. 1 and 2), made integral with closure 
structure 26, by means such as unitary rivet 33, is oriented diametrically 
of the cylindrical can; working end 36, longitudinally opposite to handle 
end 38, is positioned contiguous to a scoreline to be ruptured. (Methods 
for fabricating a sheet metal rivet button and securing an opener to a 
closure structure with a unitary rivet are known in the art so as not to 
require detailed explanation for purposes of understanding concepts of the 
present invention.) 
The sheet metal of the closure structure is scored in a continuous line. 
Resulting scoreline 40 is located radially inwardly of, but contiguous to, 
the closure structure flange metal 29 and the resultant can chime seam 30. 
The reduced sheet metal thickness scoreline 40 is strategically positioned 
for providing the desired opening and, for safety purposes after opening. 
After opening, the severed edge of scoreline residual metal of that minor 
portion of original end wall panel 42 which remains with the can body is 
shielded. That is, user protection is provided should a consumer 
accidentally insert a finger into the opened end of the can. 
Such protection is provided by scoreline placement and disposition, in 
coordination with a can body configuration which inhibits cutting contact 
with such severed edge of the residual metal of the scoreline; thus, 
accidental cutting is substantially precluded by multiple concepts which 
are shown and explained in more detail in relation to later figures. 
At the opposite end of the can body, unitary bottom wall 25 is 
substantially planar (as shown in cross section in FIG. 1) except for 
nodules such as 44, 45, 46 of FIG. 3. These nodules extend externally in 
relation to the cup-shaped can body 21 beyond the transverse plane of the 
main panel of end wall 25. The important function of such nodules is to 
support a can, on end, in slightly spaced relationship from a heating 
surface, e.g., when a baby food can is placed, open end up, in a pan of 
water resting on a burner for purposes of heating the contents of the can. 
Nodules 44, 45, 46 are oriented in a tripod arrangement in FIG. 3 but 
other arrangements, with additional nodules positioned for stable support, 
can be utilized. 
The cup-shaped configuration, per se, of can body 21 is formed by 
draw-redraw practice with special stepped-flange tooling and bottom nodule 
tooling being utilized as final redraw is being completed. 
Initially, a circular blank of predetermined diameter is cut from 
flat-rolled sheet metal coated with an organic coating on both its planar 
surfaces. Such cut blank is formed into cup 48 (FIG. 4) having end wall 
49, side wall 50 and flange metal 51, at the open end of the cup, 
extending radially outwardly in transverse relationship to the central 
longitudinal axis. In forming a baby food can, cup 48 has an internal 
diameter of about 3.5", a side wall height of about 1.27", a radius 
between end wall 49 and side wall 50 of about 0.2", and a radius between 
the side wall and flange metal of about 0.04". 
In the illustrated embodiment, which uses a double redraw, cup 48 is then 
redrawn into redrawn cup 52, shown in FIG. 5, presenting a decreased 
diameter end wall 53, increased-height side wall 54 and flange metal 55 at 
the open end of the redrawn cup. Flange metal 55 extends radially 
outwardly in transverse relationship to the center longitudinal axis of 
the cup. In forming a baby food can, work product 52 has a diameter of 
about 2.4", a side wall height of about 2.0", a radius between bottom wall 
53 and side wall 54 of about 0.07" and a radius between the side wall 54 
and flange metal 55 of about 0.04". 
Final can body 21 is formed by redrawing the cup 52 of FIG. 5 to further 
decrease its diameter, to that shown for end wall 25 and side wall main 
body 24 (FIG. 1), and to elongate the side wall of cup 52. 
As redrawing of cup 21 is being completed, the stepped-flange rim 22 is 
formed utilizing a portion of the side wall metal and the flange metal of 
the previous work product cup 52. 
For example, in the stepped-flange rim 22 of FIG. 6, the diameter of wall 
portion 59 was the diameter of side wall 54 of cup 52 of FIG. 5. Ledge 60, 
which lies in a plane substantially transversely perpendicular to central 
longitudinal axis 26 and is toroidal in plan view, is formed by 
interrupting the second redraw before reaching the open end of the can 
body; the diametric dimension of ledge 60 comprises the reduction in 
diameter during such final redraw. Seam flange metal 62, at the 
longitudinal end of the can body 21 and at the periphery of rim 22, 
comprises a portion of flange metal 55 from the work product 52 of FIG. 5, 
after trimming. 
In forming stepped-flange rim 22, the final redraw stroke is interrupted so 
that neither the metal of side wall portion 59, nor flange metal 62, are 
re-formed during final redraw. 
In forming a baby food can, the diameter of the main body side wall 24 of 
FIG. 6 has an internal diameter of about 21/8"; the radius between end 
wall 25 and side wall 24 is about 1/8", the internal diameter of rim side 
wall portion 59 is about 2.4", the ledge 60 has a radial dimension (one 
side of the can body) of about 0.17", the radius between side wall 24 and 
ledge 60 is about 0.03", the radius between wall portion 59 and flange 62 
is about 0.07". 
As shown in FIG. 6, flange metal 62 has been trimmed to be of uniform 
diameter utilizing commercially available flange trimming apparatus, 
preferably of the type described in U.S. Pat. No. 4,404,836 of Sept. 20, 
1983, entitled "Metal Container Edge Trimming Method and Apparatus". 
Referring to FIG. 7, in forming a unitary can body, in accordance with the 
invention, continuous strip coated with organic coating on both its 
surfaces from coil 64 is lubricated as coiled or at lube station 65. A 
circular blank of predetermined diameter is cut from the sheet metal and 
drawn at cupping and blanking station 66 into the cup-shaped work product 
with flange metal shown in FIG. 4. 
The cup with flange metal is lubricated on both its surfaces with an 
FDA-approved lubricant at cup lube station 67 using apparatus as disclosed 
in copending U.S. application Ser. No. 681,630, filed Dec. 14, 1984, 
entitled "Electrostatic Lubrication of Cup-Shaped Can Bodies". The 
lubricated cup is then drawn at first redraw station 68 into the work 
product shown in FIG. 5, relubricated on both surfaces at station 69 and 
transferred to the final redraw station 70. As indicated at 71, profiling 
of the closed end wall providing, for example, nodules 44, 45, 46, can be 
completed utilizing a portion of the stroke of the final redraw apparatus. 
The stepped-flange rim 22 of FIG. 6 can also be formed utilizing such 
final redraw apparatus as indicated by 72. 
At station 74 flange metal is trimmed and the can body is inspected at 
station 75. Filling and closure can be completed at station 76 for 
delivery of assembled can 20. 
FIG. 8 is a partial view at the final redraw station as the diameter of the 
work product is being reduced by relative movement between draw die 78, 
draw ring 79, and draw punch 80 as indicated. The sheet metal at 81 is 
draped across nodule-forming pins, such as 82, which move with draw punch 
80. 
Subsequent to FIG. 8, as shown in FIG. 9, the bottom profiling is completed 
by contact of draw punch 80 with end wall die 84; and, the stepped-flange 
rim 22 is formed, as shown, by interrupting the redraw before reaching the 
open end of the can body. The side wall portion 59 of the stepped-flange 
rim 22 comprises, as mentioned, a portion of the side wall of the previous 
work product; the ledge 60 shown comprises the reduction in diameter of 
the final redraw, and flange 62 is part of the flange metal from the 
previous work product. Side wall portion 59 and flange metal 62 are not 
redrawn in the final redraw operation but, rather, the draw die and draw 
ring 79 are contoured to the desired stepped-flange rim configuration. 
FIGS. 10, 11 and 12 are partial views from shop assembly type drawings 
showing portions of tooling and work product during forming of a closure 
structure in accordance with the invention. 
A flat-rolled sheet metal blank of circular configuration and predetermined 
diameter is cut from sheet or strip material. The blank is initially 
forced, as shown in FIG. 10, to present a generally planar end wall panel 
42 recessed longitudinally from peripheral flange 84. Finger indentation 
85 is also impressed in end wall panel 42. 
In this first forming operation, tooling 86 impresses externally directed 
protrusion 88 as tooling 90 starts formation of a button contour 91 for 
unitary rivet 33. In two sequential steps, not illustrated, such initial 
contour for a rivet button is progressively shaped in a manner known in 
the art. 
Rivet button 92 is completed in the step represented by FIG. 11. In this 
step, a trough 94 of U-shaped configuration (in radial cross section) is 
formed about the periphery of end wall panel; such trough extends in the 
axial direction, protruding on the can interior surface of the closure 
structure. Trough 94 is recessed in relation to the can exterior surface 
of panel 42 and is located between panel 42 and closure wall portion 95; 
ledge 96 and wall portion 97 extend to flange metal 84. 
FIG. 12 shows scoring tool 98 forming scoreline 40 in the bottom of trough 
94. The scoreline 40 is continuous, extending around the length of the 
trough which circumscribes panel 42. Rivet button 92 is ready for the next 
operation in which an elongated opener is placed over such button and the 
unitary rivet 33 is formed in accordance with known methods. 
The end closure 26 of FIG. 12 has a diameter of about 2.75" dependent on 
the length of flange metal 84 with the midpoint of flange metal for chime 
seam purposes being about 2.6". Trough 94 has a depth between about 0.03" 
to 0.05" (relative to panel 42) and width of 0.1" (in radial cross 
section). Trough wall portion 95 has a height of about 0.085", ledge 96 a 
radial cross-sectional width of about 0.16", and wall portion 97 a height 
of about 0.12". The centerline of rivet 33 and centerline of protrusion 88 
are each about 0.832" along the diameter of closure structure 26 from its 
center. 
An enlarged schematic view of a portion of can body 21 along with a 
similarly enlarged schematic view of a portion of the closure structure 26 
are shown in juxtaposition in FIG. 13. 
The stepped-flange of can body 21 presents side wall portion 59, 
intermediate ledge 60 and flange metal 62. Compound curvilinear transition 
zone 100 extends between ledge 60 and can body side wall 24 and presents a 
rounded convex edge oriented in the direction of central longitudinal axis 
26. 
The portion of closure structure 26 of FIG. 13, shown in juxtaposition 
(above and to the right of) the stepped flange of can body 21, is moved 
during can assembly such that its flange metal 84 overlays the flange 
metal 62 of the can body 20 providing flange metal for the double chime 
seam 30 of FIG. 1. 
When thus assembled, scoreline 40 is contiguous to ledge 60. Trough 94 
overlays ledge 60 with scoreline 40 at the radially outward portion (with 
respect to central axis 26) of the compound curvilinear transition zone 
100. 
The severed residual metal edge is shielded by placement of the scoreline 
40 in the bottom of U-shaped trough 94. Consider the full-opening pull-out 
removed from panel 42. Because the scoreline 40 is in the bottom of trough 
94, the severed residual metal edge (0.002" to about 0.0025" for steel) is 
not presented as a knife edge but, rather, only as a portion of a 
significantly thicker edge represented by the depth of trough 94. Only a 
minor portion of such thickened edge presents a severed metal edge. 
Protection for such minor edge portion on the throwaway panel pull-out is 
provided by selection of the depth of trough wall 101. 
The severed residual metal edge which remains affixed to the can body after 
opening is additionally shielded. That is, in addition to thickened-edge, 
trough-wall protection, the rounded convex edge of can body 21 at 
transition zone 100 protects this severed residual metal edge. 
Because of the curved transition zone 100, and the position of the severed 
scoreline metal contiguous to ledge 60, it is impossible to use such 
residual metal as a cutting edge. It is possible to sense by hand, on an 
opened can, that a scored metal edge is contiguous to ledge 60 and 
transition zone 100 but it would be difficult for a consumer or user to be 
scratched, let alone cut, by that edge. 
Typically, double-reduced flat-rolled steel would be used for manufacture 
of can bodies for a baby food can. Both surfaces of such flat-rolled steel 
would include an organic coating. A TFS (tin-free steel) coating or other 
plating, selected for adherence of the organic coating, would be 
intermediate the steel base metal and outer organic coating. 
The closure structure would typically be made from single-reduced 
flat-rolled steel. Flat-rolled aluminum could be used for the can body, 
closure, or tab opener. 
Typical sheet metal gages are as follows: 
______________________________________ 
Part Steel Aluminum 
______________________________________ 
can body .005-.009" 
.007-.012" 
closure structure 
.007-.009" 
.008-.011" 
tab opener .011-.015" 
.014-.020" 
______________________________________ 
The can body configuration of FIG. 14 enables an assembled can to roll, on 
its side, in a straight line. The purpose of this is to enable heat 
treatment of can contents, e.g. baby food, for either cooking or hygienic 
reasons, in conventional ovens. So-called "retorting" ovens convey baby 
food containers on their sides, which requires them to roll symmetrically 
about their central longitudinal axis. 
The present invention provides a can body side wall configuration which 
provides for the chime seam at the open end of the can body to have 
substantially the same diameter as the main body portion of the can body 
side wall. In addition, the present invention avoids use of an abrupt 
necked-in or lip portion at the open end which would tend to inhibit 
discharge of contents or make access under such an abrupt necked-in or lip 
portion difficult. 
Rather, a beveled side wall makes a smooth longitudinal transition from the 
main body side wall portion toward the open end of the can body. The 
desirable convenience and protection features, previously discussed, are 
maintained while further facilitating heat treatment of an assembled can 
in commercially available ovens. 
Referring to the cross-sectional view of FIG. 14, a beveled side wall 
one-piece can body 104 is symmetrical about central longitudinal axis 105. 
Closed end wall 106 is unitary with cylindrical configuration main body 
side wall portion 107 and beveled side wall portion 108 which extends 
longitudinally toward the open end of the can body. 
Stepped-flange rim 109 extends from a reduced-diameter cylindrical wall 
portion 110 and includes ledge 111, rim wall portion 112 and peripheral 
flange metal 114. Stepped-flange rim 109 serves the corresponding 
purposes, for adding an end closure structure and protecting severed 
scoreline metal, as described in relation to stepped-flange 22 of earlier 
figures. However, in forming a chime seam with can body flange metal 114 
and flange metal 84 of closure 26, the outer diameter of the chime seam 
thus formed is substantially equal to the outer diameter of main body side 
wall portion 107. 
The beveled side wall 108 of FIG. 14 is preferably fabricated by selecting 
tooling conforming to the desired configuration of side wall 108 and use 
of eccentrically-mounted side wall rolling apparatus of the type available 
from the Carnation Company, 5045 Wilshire Blvd., Los Angeles, Calif. 
90036, or from Metal Box Engineering, Queens House, Forbury Road, Reading 
RG1 3JH, Great Britain; more conventionally, such apparatus is used for 
rolling reinforcing ribs into tubular side walls of sheet metal cans. 
In fabricating the can body of FIG. 14, the final can body is redrawn to 
the diameter of main body side wall portion 107 with extra length flange 
metal oriented transversely to the central axis of the cylindrical side 
wall; such added length flange metal provides for pulling-in of flange 
metal into the side wall during eccentric rolling of the side wall. 
Beveled side wall portion 108 is eccentrically rolled into the cylindrical 
wall portion above main body portion 107 starting at the juncture 115 
between such wall portions and working toward such open end. After 
eccentric rolling of beveled side wall portion 108, stepped-flange rim 109 
is formed, above reduced-diameter wall portion 110, from reduced-diameter 
side wall and flange metal at the open end of the can body. 
The following dimensions are typical for a baby food can body of the 
configuration shown in FIG. 14: 
______________________________________ 
Diameter 
Height 
______________________________________ 
Main body side wall 107 
1.625" .675" 
Beveled side wall 108 
1.25" 1.0" 
(at reduced-diameter 
110) 
Wall portion 110 1.25" 0.15" 
Rim wall 112 1.52" .083" 
______________________________________ 
Such wall heights do not include dimensions of compound curvilinear 
transition zones between horizontal and vertical portions of the can body; 
such radius dimensions are tabulated below: 
______________________________________ 
Transition Zone Approximate 
between Radius 
______________________________________ 
flange 114 and wall 112 .06" 
wall 112 and ledge 111 .07" 
ledge 111 and wall 110 .03" 
wall 110 and wall 108 .09" 
wall 108 and wall 107 .10" 
wall 107 and bottom 106 .20" 
Ledge 111 has a radial dimension of about 
.27". 
______________________________________ 
The configuration of FIG. 14 could also be formed by removing flange metal 
after a draw-redraw process, by progressively necking-in the side wall 
above 115 to the reduced diameter of side wall portion 110, then forming 
the stepped-flange rim in necked-in metal remaining above the 
reduced-diameter wall 110. 
While specific values relating to materials, dimensions, and geometric 
relationships have been set forth for purposes of describing the 
invention, other values could be adapted by those skilled in the art to 
the disclosed concepts in the light of the present teachings; therefore, 
for purposes of determining the scope of this invention, reference should 
be made to the accompanying claims.