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Description  |
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BACKGROUND OF THE INVENTION
This invention relates to easy opening cans and, more specifically, to an
improved easy opening container wall including inseparable tear strips,
each defined by a separate score line, wherein the tear strips may be
opened with a single retained tab member, and wherein protective means are
incorporated in order to reduce the incidence of laceration.
The ready acceptance of easy opening containers has resulted in extended
use of this type of container for a substantial number of canned products,
especially beverages such as beer, soft drinks and the like, as well as
other products which are non-carbonated. This type of container is
characterized by a lever or tab permanently joined to a tear strip, the
latter normally bein separable from the can top to provide a pouring
spout, in the case of beverages. In the form heretofore used, the tab or
top is ruptured along a continuous score line and the pull tab and tear
strip is normally removed and discarded.
The convenience of easy opening cans has created problems because of the
unfortunate and indiscriminate disposal of the severed portion of the can
top. For example, beach and picnic areas have had an accumulation of
litter in the form of tabs and tear strips which have been removed from
easy opening cans. These discarded tabs and tear strips are quite
difficult to clean up because they are small and thus pass through the
tines of a rake. Being made normally of aluminum, they cannot be collected
by magnetic means. Nonetheless, this type of can is widely used and it is
definitely advantageous to provide a solution to the problem of littering
while still providing to the public the convenience of easy opening
containers.
The numerous advantages incident to the use of easy opening cans are
significantly enhanced if a container end is provided including an
inseparable tear strip and which is relatively safe to use in the sense
that the incidence of lacerations are reduced. As will be appreciated,
where a tear strip is not separable from the end wall, precautions must be
taken to prevent laceration by the retained tear strip or by the exposed
edge of metal formed upon opening of the container. This is particularly
true with respect to small children who exhibit a tendency to place their
fingers down into the pour opening of an easy opening container.
The packaging industry is generally aware of the problem of indiscriminate
littering of separable tabs and tear strips as well as the potential
problem of laceration.
Accordingly, it is definitely advantageous to provide an easy opening end
wall structure with a retained tear strip system in that there are no
detachable components which may be thrown away as litter. In such an end
structure, it is desirable to retain, to the extent possible, the opening
action, which is in the form of lifting to bring about rupture of the
score lines, since the public is accustomed to this type of opening action
in an easy opening end wall.
It is also advantageous to provide an easy opening end structure having the
advantages previously noted that is a conversion and interchangeable with
present tooling used by the industry in the sense that the basic container
dimensions need not be altered in order to accommodate the improved end.
An additional factor is that the end should provide normal performance for
the variety of products packaged in convenient easy opening end type
containers, for example, an end structure which is capable of withstanding
the normal pressures utilized in the beer and beverage industry, and
particularly those products packaged under pressure or which develop
pressure during their packaging, for example, pasteurization of certain
beer type products.
DESCRIPTION OF THE PRIOR ART
It is known to use a noncontinuous score line such that the tear strip is
firmly attached to the container. Such a structure is shown in U.S. Pat.
No. 3,327,891.
An improvement in the structure described in the above-identified U.S.
Patent is described in U.S. application Ser. No. 103,255, filed Dec. 31,
1970, as well as U.S. application Ser. No. 346,712, filed Mar. 30, 1973,
each assigned to the same assignee as this application.
Recently, beverage and beer containers have appeared in commercial use
which include a push type opening which is ruptured by pushing downwardly
upon a panel and folding it into the container. This type of structure is
objectionable principally because of the laceration problem since it is
necessary for the user to place his finger through the pour opening during
the opening operation.
SUMMARY OF THE INVENTION
The present invention relates to an easy opening container wall structure
which offers several distinct advantages not heretofore found in prior
devices. The container end wall of the present invention includes a
retained tear strip structure in that the tear strip cannot be discarded
once the pour opening has been formed. Moreover, recognizing the need to
provide an easy opening container which vents properly during the opening
sequence, the end wall of the present invention includes a separate vent
opening, the pour opening and the vent opening being provided in a single
opening sequence which follows generally the opening operation heretofore
used with the more conventional easy opening container ends.
More specifically, the easy opening wall of the present invention includes
an end wall and a first line of weakness in the end wall which defines a
tear portion partially removable from the end wall to form a pour opening.
Also provided in the end wall is a second line of weakness, spaced from
the first line of weakness, and defining a vent tear portion partially
removable from the end wall to form a vent opening. A tab structure is
attached to each of the tear portions, preferably by an integrally formed
rivet, and is used to rupture the lines of weakness and is likewise
retained on the end wall after the opening sequence.
Each line of weakness includes an associated means for preventing complete
removal of the ruptured tear strips. Accordingly, as the tab is
manipulated to rupture the score lines, inseparable tear strips are formed
which are joined to the tab and the tab and tear strips can be folded back
against the end walls of the container, out of the way of the user, but
retained on the container end wall.
Another feature of the present invention is the provision of protective
means associated with the tear strip which forms the pour opening and the
residual metal which surrounds the pour opening. In one form, a raised
protective bead is formed adjacent to the score line forming the pour
opening thereby substantially reducing the possibility of laceration. It
will be appreciated, that the system described for protecting against
laceration is not fool proof but operates substantially to reduce the
possibility of laceration by virtue of a beaded formation which tends to
prevent the user's finger from coming into cutting contact with the free
edge of metal surrounding the pour opening.
The tear strip which is partially severed to form the pour opening likewise
includes a beaded formation which performs several different functions.
With the beaded formation in accordance with the present invention, it is
in the form of a downwardly extending depression such that the pressure
from the interior of the container operates to maintain the adjacent score
line in compression thus increasing the strength of the score line to some
extent. Moreover, the depression acts as a strengthening means to prevent
the bending of the ruptured tear strip thereby allowing it to be hingedly
folded back against the end wall. In the open and folded position, the
depression now appears in the form of a protrusion which prevents the
user's fingers or nose or lips from coming into contact with the sharp
edges which are formed along the severed portion of the tear strip.
The vent opening and the pour opening, as already described, cooperate with
the tab to form a hinge line by which each of the tear strips is hingedly
foldable against the end wall of the container. In a preferred form, the
distance from the center of the rivet to the hinge line at the vent
opening is less than the distance from the center of the rivet to the
hinge line of the pour opening such that one end of the tab is rotated
through a greater arc than the other end of the tab.
The end structure also includes depressions in the end wall, one
cooperating with the tab to permit the user's finger to be inserted
beneath the tab, and the other positioned such that the folded vent strip
and pour strip may be pushed flat against the end wall by pushing the tab
into the depression. This latter depression generally follows the contour
of the tab itself and in effect forms a tab receiving pocket.
Further objects, advantages, and modes, and such additional embodiments of
the present invention will be readily apparent to those skilled in the art
after they have read the detailed description and referred to the
accompanying drawings which illustrate what are presently considered to be
preferred embodiments of the best mode contemplated for utilizing the
novel principles which are defined in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view, on a somewhat enlarged scale, of a container end
wall in accordance with the present invention;
FIG. 2 is a view similar to FIG. 1 with the tab structure removed so that
further details of the structure of the container end wall of the present
invention may be seen;
FIG. 3 is a view in section, with portions thereof being in elevation,
taken along the line 3--3 of FIG. 2;
FIG. 4 is a view, partly in section and partly in elevation taken along the
lines 4--4 of FIG. 2;
FIG. 5 is a view, partly in section and partly in elevation taken along the
lines 5--5 of FIG. 1;
FIG. 6 is a fragmentary view, in perspective, of the container end wall of
the present invention illustrating the relative position of the parts
during the start of an opening sequence;
FIG. 7 is a view similar to FIG. 6 but illustrating the relative position
of the parts after complete severance of the vent opening and pour opening
in accordance with the present invention;
FIG. 8 is a view similar to FIG. 6, showing the tab structure and vent and
tear openings being folded back in accordance with the present invention;
FIG. 9 is a plan view of a container end wall in accordance with the
present invention, on a somewhat enlarged scale, showing a modification of
a tab structure usable in accordance with the present invention; and
FIG. 10 is a view, partly in section and partly in elevation taken along
the lines 10--10 of FIG. 9.
DETAILED DESCRIPTION OF THE INVENTION
Referring to the drawings which illustrate a preferred form of the present
invention, FIG. 1 illustrates a container end wall generally designated
10, the container end wall being formed of sheet material as, for example,
aluminum alloys and the like or any of the other materials capable of
being used in the formation of end walls for convenience type containers.
A typical such alloy is 5082H19 of a thickness of 0.0135 inches. The
container end wall 10 includes an end wall panel 12 and a peripherally
extending flange 13 (FIG. 4) joined to the end wall panel by a chuck wall
14. The container end wall 10 is attached to a container body in the usual
manner, well known in the art.
The end wall panel 12 includes a first line of weakness 15 in the form of a
score line which is noncontinuous in the sense that it does not extend in
a full 360.degree. circle. The first line of weakness defines a tear
portion 17 which is at least partially removable from the end wall, the
removal of the tear portion 17 forming a pour opening. Spaced from the
first line of weakness 15 is a second line of weakness 18 in the form of a
score line, defining a tear strip 19, the latter likewise being partially
removable to form a vent opening. The score lines may be of the
conventional V-shaped score type, or a pinched score line, as is known in
the art, may be used.
A tab element generally designated 25 is attached to each of the tear
portions 17 and 19 by integral rivets 27 and 29, respectively. The end
wall panel 12 also includes a plurality of depressions 30 and 31,
depression 30 forming a tab receiving depression and tab 31 forming a
finger well to enable the user to insert his finger between the end wall
panel and the underside of the tab 25 in order to operate the tab in an
opening sequence.
Referring now specifically in FIG. 2, each of the lines of weakness 15 and
18 is configured to prevent removal of the associated tear panel. To
accomplish this, score line 15 terminates in reversing curves 33 and 34,
as illustrated, while score line 15 likewise terminates in reversing
curves 36 and 38, the reversing curves 33-34, and 36-38, operative to
prevent continued tearing of the metal as the vent strip and pour strip
are ruptured by the tab 25, as will be described hereinafter.
As in known, the rupture of sheet metal to form a pour opening frequently
results in the formation of sharp peripheral edges, on each of the end
panel and on the tear strip. Accordingly, in accordance with this
invention, protective means are provided both on the end panel and the
pour strip to provide protection against laceration.
Referring to FIGS. 2-5, the end wall 12 in the portion thereof surrounding
the score line 15 which forms the pour opening includes a generally
annular raised flat 40, the flat in turn including a protective bead 42
which circumscribes that portion of the end wall which defines the pour
opening. As illustrated, the score line 15 is located on the raised flat
40 and closely adjacent to the protective bead 42. Thus, as the score line
15 is ruptured, the amount of laterally extending residual cutting edge is
reduced. Moreover, the presence of the protective bead 42 tends to inhibit
contact between the free edge and the user's finger. As shown in FIG. 2,
the ends 46 of the protective bead 42 terminate a short distance from the
reversing curves 36 and 38. Since the vent opening normally does not
create any problems with respect to laceration due to its relatively small
opening, it is not necessary to provide the vent opening or the vent tear
strip with any form of protective bead or other form of protective device.
In order to protect the user from laceration by the portion of the end wall
panel which constitutes the pour opening tear strip 17, the latter is
provided with a downwardly extending depression 50, which in addition to
forming a protective means forms several other functions as will be
described.
As illustrated in FIGS. 2 through 5, rivet 27 is positioned in a rivet well
52 formed in panel 17, the rivet well being generally planar and at
approximately the same vertical level as the raised flat 40. Cooperating
with the rivet well is a generally arcuate, sloping wall 53 whose maximum
relative dimension is illustrated in FIG. 4 and which generally decreases
in dimension to the right and to the left of the section line 4--4 of FIG.
2. The sloping wall 53 operates to permit the rivet to be placed in a flat
plane while likewise permitting the downward depression 50 to be formed
into the tear panel 17 which forms the pour opening.
One function of the downward depression 50 is to maintain the associated
score line 15 in compression, especially in those instances in which the
contents in the container are under some pressure. Referring to FIG. 3,
for example, pressure on the underside 54 of the depression 50 operates to
maintain the score line 15 in compression. In this way, score line
integrity is enhanced, particularly in those instances in which the
contents of the container are under considerable pressure as may be the
case with certain types of carbonated beverages. Score line integrity is
also important in those instances in which the processing involves the use
of a pasteurization step which creates substantial pressures during the
pasteurization operation. The downward depression 50, in that particular
instance, also acts to prevent considerable bulging of the container end
in the sense that the container end takes a permanent set in the domed
configuration.
Referring to FIGS. 6 through 8 wherein like reference numerals have been
applied, the opening sequence of the container end wall may be understood,
as well as the additional functions performed by the protective depression
50. As illustrated in FIG. 6, the user inserts his finger between the tab
25 and the finger well 31 and lifts the tab 25 in an upward direction,
following generally the operation used in opening a beverage container
having a ring type pull tab. During the initial movement of the tab 25,
the score lines 18 and 15 are stressed, preferably such that score line 18
begins to rupture immediately prior to the start of rupture of score line
15. As long as the vent score line 18 starts to rupture immediately prior
to, or simultaneously with the rupture of score line 15, the venting
action sought to be achieved in accordance with the present invention is
obtained. Thus, the initial manipulation of the tab is effectively a
rotating action in the sense that the end 56 of the tab is lifted upwardly
and the edge portion 57 is rotated downwardly in stressing the score lines
18 and 15 in the portions generally designated 58 and 59, respectively.
Since the single tab 25 is attached at its ends 61 and 62 to rivets 29 and
27, respectively, the manipulation of the single tab element is effective
simultaneously to open both score lines either simultaneously or with the
score line of the vent opening being initially popped slightly ahead of
the score line for the pour opening.
As the user continues to manipulate the tab 25 by a rotating lifting action
towards a vertical plane, the score lines 15 and 18 are ruptured to the
point of the reversing curves associated therewith which, as earlier
indicated, operate to prevent complete severance of the vent tear strip
and the pour strip from the end wall. Thus, a fold zone 65 exists, as
illustrated in FIG. 1 between lines 65a and 65b which effectively forms a
hinge line for the vent panel and pour panel resulting from severance of
the score lines 15 and 18.
As illustrated in FIG. 1, the center point from rivet 29 to the fold zone
is substantially less than the distance from the center of rivet 27 to the
fold zone 65. Accordingly, to effect complete severance of the score lines
while providing the retained tear strips, it is necessary that the end 62
of the tab 25 move through a greater arcuate distance vertically above the
end wall than the end 61.
Referring to FIG. 7, the general vertical orientation of the tab 25
attached to the tear strips 67 and 69 is illustrated, as well as the
difference in vertical heighth above the end wall of the ends 62 and 61 of
the tab 25.
In the type of opening action described, it is important that the tear
strip 69 be folded about the fold zone 65 rather than midway or part way
through the panel. Accordingly, another function of the depression 50 is
to provide structural integrity to the tear strip 69 thereby assuring that
it folds along the fold zone 65 rather than folding in the middle. Since
the length of tear strip 67 is relatively short, no reinforcement is
needed since the legs 71 and 72 of the score line are relatively short
from the center point of the rivet to the reversing curves 33 and 34.
Once the tab has been elevated to the vertical position with the tear
strips oriented generally in a vertical position, it is possible for the
user to continue to rotate the tab around the fold zone 65 and to push the
tab 25 into the tab receiving well 30. Such a relative position is
indicated in FIG. 8 with the tab in its initial position indicated by the
dotted lines 74.
In the opened condition, as illustrated in FIG. 8, with the tab 25 pushed
into the tab receiving pocket 30 and with the tear strips folded about the
fold zone 65, depression 50 now appears as a protrusion rising above the
folded pour strip 69. The protrusion 50 which extends above the surface of
the end panel protects the user from contacting the exposed edges on the
tear strip 69 since the panel is folded against the end wall and in
contact therewith by virtue of the fact that the depression 30 receives
the tab. Thus, the protective depression, now operating as a raised
projection, assists materially in preventing the user's nose or fingers
from contacting the exposed edge of metal along the periphery of the panel
69.
As seen in FIG. 5, the rivet 27 is somewhat vertically above the rivet 29
and in order for the tab 25 to lay flat against the end panel of the
container end wall, it includes a vertically raised section 80 at the end
62 thereof to which the rivet 27 is attached. The other end 61 is attached
to rivet 29, with the portion 80 being raised along a generally angularly
disposed line 83 as seen in FIG. 1.
While the above structure operates effectively and in the manner described,
it will be apparent that modifications may be made. For example, referring
to FIGS. 9 and 10 wherein the same reference numerals have been used where
applicable, the tab 95 is attached to the rivets 29 and 27, the tab
including a fold shoulder 96 at the junction between the body portion 98
and the end 99 attached to the rivet 27. The fold shoulder operates to
contact the end panel of the container during the operation of the tab
thereby permitting somewhat easier rupturing of the score line 15 in the
tear panel which forms the pour opening.
In all other respects, the end panel is essentially the same as that
previously described.
The end structure of the present invention may be easily manufactured in a
series of operations on an end blank. For example, that tab well and
finger well are first formed, the depression and bead are then formed, the
scoring then placed, and finally the tab is staked. It is understood that
the rivet button may be formed in the bubble and button stages or what is
called a single hit rivet.
While the pour opening has been shown as generally circular in shape, other
shapes may be used because of the presence of a vent opening separate from
the pour opening which substantially improves the pouring characteristics
of a container with an end wall as herein described.
It is to be understood that depression 50 may be a protrusion if only a
stiffening means is needed to prevent the pour panel from folding during
an opening sequence. Where protection and increased score integrity are
also desired, the depression will achieve all three functions, as
described.
One of the definite practical advantages of the present invention is the
fact that venting is easily accomplished by a separate vent opening
located in a portion of the end panel other than where the pour opening is
located. Also, since the tab is rigidly held by rivets to the tear panels
which are inseparable from the end wall and folded into the tab receiving
recess 30 after opened, there is little tendency to remove the tab from
the tear strips to which it is attached. Since the entire opened end of
the end wall is folded back, it is, in a sense, out of the user's way and
there is no need for any further manipulation of the tab or the tear
strips during the dispensing of whatever material is within the container.
Another practical advantage of the end structure of the present invention
is the fact that the pouring characteristics of the container are enhanced
considerably by the use of a separate vent opening. As shown in the
drawings, the pour opening is located closely adjacent to the chuck wall
which places the vent opening in the upper quadrant of the container
during a normal pouring operation. This permits air to come in through the
top of the container while liquid is being dispensed from the lower end,
in a pouring operation. It is for this reason, that the rivets are located
on a straight line which defines a cord with respect to the end wall, the
cord being so located as to permit the tab and retained but fractured tear
strips to be folded back into the end wall and out of the way of the pour
opening and the vent opening.
Thus, the container end structure of the present invention offers several
advantages over the prior art structure including a retained tear strip
structure and more importantly a retained tab structure which is not
easily removed from the tear strips. Means are provided to protect the
user against laceration, and there is no need for the user to insert a
finger into the pour opening. Even so, if this is done, there is a measure
of protection provided by the protective beads which surround the major
portion of the pour opening, as described, and thus protection is afforded
against laceration. Accordingly, the combination of a retained tear strip,
attractive from an ecology standpoint, with the protective features as
described, and the highly desirable pouring characteristics all offer a
combination of advantages which are sought after in the design of
container end structures.
It will be apparent to those skilled in the art that there are several
features of the present invention. Thus, many modifications and
alterations of the disclosed and described embodiments may be made as will
be apparent to those skilled in the art, without departing from the scope
of the invention as defined in the following claims.
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