U.S. patent number 3,850,124 [Application Number 05/331,645] was granted by the patent office on 1974-11-26 for easy opening container wall.
This patent grant is currently assigned to Ermal C. Fraze. Invention is credited to Omar L. Brown.
United States Patent |
3,850,124 |
Brown |
November 26, 1974 |
EASY OPENING CONTAINER WALL
Abstract
An easy opening container wall including a container wall having
a line of weakness therein defining a tear portion at least
partially removable from the container wall and a tab affixed to
the tear portion to initiate severance thereo from the container
wall. The tab has a rupturing portion which overlies a location on
the container wall closely adjacent the line of weakness. The tab
has a hinge line which extends between said location and the region
of attachment of the tab to the tear portion so that by
manipulating the tab, a segment of the tear portion is forced
inwardly generally about a bend line. The tear portion has a
weakened region therein positioned to facilitate the inward bending
of the segment about the bend line. Although various kinds of tabs
may be used, the tab preferably includes a lever portion and an
attachment portion joined by a connecting wall. A marginal portion
of the tab is bent inwardly to form a curl having a double layer
portion which is engageable with the connecting wall to support the
latter. According to another feature of the present invention, the
tab is made in a strip of sheet material and the carrying strip
therefor is positioned at the lifting end of the tab.
Inventors: |
Brown; Omar L. (Dayton,
OH) |
Assignee: |
Fraze; Ermal C. (Dayton,
OH)
|
Family
ID: |
26744361 |
Appl.
No.: |
05/331,645 |
Filed: |
February 12, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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64291 |
Aug 17, 1970 |
3720349 |
|
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Current U.S.
Class: |
413/25 |
Current CPC
Class: |
B65D
17/4011 (20180101); B21D 51/383 (20130101) |
Current International
Class: |
B21D
51/38 (20060101); B21d 051/44 () |
Field of
Search: |
;113/121C,1F
;220/54 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Herbst; Richard J.
Attorney, Agent or Firm: Martella; Mario A.
Parent Case Text
This application is a division of Ser. No. 64,291 filed Aug. 17,
1970, now U.S. Pat. No. 3,720,349.
Claims
I claim:
1. A method of making a tab of the type attachable to an easy
opening container wall to initiate severance of a segment of the
container wall wherein said tab includes a body having a lifting
end movable away from the container wall and an attachment portion
for fastening to the container wall and means defining an opening
to accommodate a user's finger, said method comprising:
providing a strip of sheet material,
forming in said strip a tab blank having a body and an inner and
outer peripheral surface,
said tab blank being integrally connected to said strip by web
means at a junction located at that portion of the blank formable
into the lifting end of said tab,
forming an inner curl on the inner peripheral surface of said blank
to protect the user's finger from laceration,
forming an outer curl on the outer peripheral surface of said blank
which is continuous along the longitudinal sides of the tab body,
said outer curl in the region of said web means including portions
adjacent to but spaced from said web means, and
severing said web means at the junction of said body so that the
line of severance is recessed towards said body whereby said
adjacent portions of said outer curl prevent contact between a
user's finger and said line of severance.
2. A method as defined in claim 1 wherein said inner and outer
curls are bent over to form a double layer of sheet material.
3. A method as defined in claim 1 wherein a rupturing element is
formed on the portion of the tab blank removed from said lifting
end.
4. A method as defined in claim 3 wherein said rupturing element is
formed by shaping said outer curl.
5. A method as defined in claim 3 wherein said rupturing element is
formed by interrupting the outer curl to form a rupturing
flange.
6. A method as defined in claim 1 wherein said strip is advanced
through several stations and wherein said tab blank is carried on
said strip solely by said web means.
7. A method as defined in claim 6 wherein said web means is located
generally centrally of the lifting end of said tab blank.
8. A method as defined in claim 1 wherein a notch is formed in that
portion of the tab blank formable into the lifting end of the tab,
and said web means being located in the area of the notch and
constituting the sole support between said strip and said tab blank
for all subsequent operations on said tab blank.
9. A method as defined in claim 8 wherein said outer peripheral
curl is interrupted by said notch, and wherein the line of
severance of said web means is adjacent to said body whereby the
portion of said outer peripheral curl is adjacent to said notch and
operates to prevent contact between a user's finger and the line of
severance.
10. A method as defined in claim 1 wherein said strip is an
elongated strip of sheet material.
11. A method as defined in claim 1 wherein said inner and outer
peripheral surfaces are formed sequentially.
12. A method as defined in claim 1 wherein said inner curl is
formed by turning the sheet material along the inner periphery
outwardly, and the outer curl is formed by turning the sheet
material along the outer periphery inwardly.
13. A method as defined in claim 1 wherein an attachment portion is
formed in said opening, and wherein said inner curl is continuous
except in the area of said attachment portion.
14. A method of making a tab of the type attachable to an easy
opening container wall to initiate severance of a segment of the
container wall wherein the tab has an outer curl extending along
the outer periphery of the tab and a lifting end movable away from
the container wall to initiate severance of said segment, said
method comprising:
providing a section of sheet material;
severing the sheet material to form a tab blank with the tab blank
being integrally connected to the section of sheet material by a
web of the sheet material and with the tab blank being completely
severed from the section of sheet material except for said web;
deforming the tab blank to form said tab with the tab being
integrally connected to said section of sheet material by said web
and with said web being at said lifting end and at least partially
interrupting said outer curl; and
severing said web to separate the tab from the section of sheet
material,
said line of severance being recessed whereby adjacent portions of
the outer curl extend outwardly beyond the line of severance.
15. A method as defined in claim 14 wherein said web is located
generally centrally of the lifting end of the tab.
16. A method as defined in claim 14 wherein said section is an
elongated strip of sheet material, said step of deforming and said
last mentioned step of severing are carried out at first and second
stations, respectively, said method including moving the strip so
that the tab moves from said first station to the second station
with the web carrying the tab in the strip between said stations.
Description
BACKGROUND OF THE INVENTION
An easy opening container wall typically includes a container wall,
a primary line of weakness in the container wall defining a tear
portion at least partially removable from the container wall and a
tab connected to the tear portion by suitable attaching means such
as a rivet to initiate severance of the tear portion from the
container wall. The tab may be of the front opening type in which
the tab has a rupturing portion which overlies a location on the
container wall closely adjacent the primary score line and is
operable upon pivotal movement of the tab to push a segment of the
container wall inwardly about a bend line. Alternatively, the tab
may be of a rear opening type in which lifting of the lifting end
of the tab lifts the leading end of the tear portion upwardly to
initiate severance thereof.
Front opening tabs are often used when the tear portion is a
relatively large panel such as in a full panel pullout. One problem
with this construction is how to facilitate the initial rupturing
of the panel from the container wall. Another problem is how to
maximize the length of arc which is ruptured in response to
pivoting of the tab. If an insufficient length of arc is ruptured,
continuation of rupture of the tear portion in response to an
outward pulling force on the tab is made more difficult.
It is also important that the tab be sufficiently strong to avoid
tearing and structural failure during use thereof. One form of tab
which has been used includes a tab body and an attachment portion
interconnected by a connecting wall. The tab body has a lifting end
and a rupturing or nose end which is forced against the container
wall in response to lifting of the lifting end of the tab to
initiate severance of the tear portion. The tab has a hinge line
intermediate the attaching means and the rupturing end. A problem
with tabs of this type is that they have been subject to structural
failure and tear out particularly when used on large panels.
Tabs for easy opening containers are typically formed in a strip of
sheet material and several operations are performed thereon at
several different stations. When the tab is being formed, it is
carried between stations in the strip and it is attached thereto by
one or more webs or carrying strips. When the tab is nipped from
the strip, the web is cut and this results in interruption of the
usual outer periphery curl of the tab. This causes weakening of the
tab or interference with the construction of various portions of
the tab such as the rupturing end thereof.
SUMMARY OF THE INVENTION
The present invention facilitates the initiation of severance of
the tear portion with a front opening tab. The present invention
employs a tab with a hinge line between the attachment means and
the rupturing end of the tab and a secondary score line in the
container wall. Pivotal movement of the tab about the hinge line
thereof bends a segment of the container wall inwardly about a bend
line, and the secondary score line is positioned to facilitate the
inward bending of such segment of the tear portion.
The secondary score line can advantageously lie at least in part
between the tab attaching means and the rupturing end of the tab.
Preferably at least a portion of the secondary score line lies
generally along the bend line about which the segment of the tear
portion bends. The secondary score line can advantageously be
located immediately under the hinge line in the tab and it may
extend in chord-like fashion toward the periphery of the tear
portion.
The shape and position of the bend line affects the length of arc
of initial rupture. The secondary score line can be used to
influence bend line configuration and thus the length of the
initial arc of rupture. Specifically the bend line, within limits,
tends to take the shape of the secondary score line if the
secondary score line lies at least in part along the region which
the bend line would inherently fall. Thus, if the secondary score
line is generally chord-like, the bend line will also tend to be
generally chord-like.
Another aspect of this invention is to interrelate the secondary
score line with an anti-fracture score line. An anti-fracture score
line is sometimes provided in the tear portion adjacent the primary
score line for allowing flexure of a section of the tear portion
when the container is subjected to an impact force such as when the
container is dropped. According to this aspect of the present
invention, a segment of the anti-fracture score is positioned to
facilitate the inward bending of the segment about the bent
line.
The tab is preferably constructed of sheet material and may include
a tab body and an attachment portion interconnected by a connecting
wall with the sheet material of the tab adjacent the juncture of
the attachment portion and the connecting wall being sufficiently
pliable to form the hinge in the tab. To strengthen the tab, a
marginal portion of the sheet material of the tab body is turned
inwardly to form an outer reinforcing bead or curl along the
periphery of the tab body. To strengthen the tab adjacent the
connecting wall, a section of the curl adjacent the connecting wall
is bent over to form a double layer of sheet material. The double
layer of sheet material is positioned so that it is engageable with
the connecting wall to support and reinforce the latter during
operation of the tab.
The tab is preferably formed at one end of the tab body with a
rupturing element. The rupturing element may be formed by merely
appropriately shaping the outer curl or by interrupting the outer
curl to form a rupturing flange.
Upon manipulation of the tab to sever the primary score line, the
tab body pivots about a hinge line extending generally transverse
to the tab intermediate the ends thereof. This pivotal movement of
the tab body causes the rupturing element to move in an arc toward
the container wall and rearwardly, i.e., toward the central region
of the container wall. The movement of the rupturing element
rearwardly about the hinge line is known as travel back and should
be minimized in front opening applications. Travel back also occurs
after initial rupture of the primary score line because the tab and
tear portion bend about different hinge lines.
One reason travel back is undesirable in front opening applications
is that it causes the rupturing element to scrape across the
container wall. This scraping action may scrape metal particles
from the container wall, which upon severance of the primary score
line may mix with the contents of the container. To facilitate
initial severance of the primary score line, the rupturing flange
should be forced generally perpendicularly downwardly at about the
moment that sufficient pressure has been created to rupture the
primary score line. This is more difficult to provide for as travel
back increases. Furthermore, the rupturing element should apply its
force directly to the sheet material at the primary score line and
this is also more difficult to provide for as travel back
increases.
To minimize travel back, the present invention provides for moving
of the hinge line of the tab closer to the plane of the tear
portion. This also moves the hinge line of the tab closer to the
bend line in the tear portion. Specifically it has been found that
the hinge line in the tab can be moved by using a portion of the
outer curl to support the connecting wall. Moreover, the location
at which the connecting wall is supported by the curl or bead
affects travel back. By moving the support region nearer the
container wall, the hinge line of the tab is moved closer to the
container wall and closer to the hinge line in the tear portion.
Accordingly, travel back is reduced.
Normally, the sheet material from which the tab is constructed is
thicker than the width of the primary score line. Accordingly, to
ensure that the rupturing element will interlock with the sheet
material at the score line, a portion of the rupturing element
preferably overhangs a region of the container wall ahead, i.e.,
outside, of the tear portion.
To avoid weakening of the tab due to nipping the tab from the strip
of sheet material in which it is formed, the present invention
provides for the tab to be carried in the strip at the lifting end
of the tab. According to this aspect of the present invention, the
sheet material of the strip is severed to form a tab blank with the
tab blank being integrally connected to the strip by a web at the
lifting end of the tab. Preferably, the web is located generally
centrally of the lifting end of the tab. The tab blank is then
deformed to form a tab of the desired configuration with the tab
being retained in the strip by the web. When the tab is nipped out
of the strip, the outer curl of the tab is interrupted at the
lifting end of the tab. Accordingly, to the extent that the tab is
structurally weakened as a result of a nipout, such weakening
occurs at the lifting end of the tab where such weakening effect
can be tolerated. If the outer curl is weakened in the
longitudinally extending portions of the curl, the ability of the
tab to withstand bending forces during use would be reduced. Also,
if the web or carrying strip were at the nose end of the tab, it
may interfere with the construction of the nose end. The nipout
point is preferably recessed to avoid possible injury to the user
as a result of contact with the severed sheet material.
The invention, both as to its organization amd method of operation
together with further features and advantages thereof, may best be
understood by reference to the following description taken in
connection with the accompanying illustrative drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top plan view of an easy opening container wall
constructed in accordance with the teachings of the present
invention.
FIG. 2 is an enlarged fragmentary sectional view taken generally
along line 2--2 of FIG. 1.
FIG. 3 is an enlarged fragmentary sectional view taken on the same
plane as FIG. 2 and showing the rupturing end of the tab and the
adjacent portions of the container wall.
FIG. 3A is a fragmentary elevational view of the tab looking
generally in the direction of the arrows 3A--3A of FIG. 3.
FIG. 4 is a bottom plan view of a tab constructed in accordance
with the teachings of this invention.
FIG. 5 is a top plan view of a tab and tab blank in a strip of
sheet material.
FIG. 6 is an enlarged fragmentary sectional view similar to FIG. 2
with the tab body having been pivoted to initiate severance of the
tear portion.
FIG. 7 is a top plan view similar to FIG. 6 showing another
configuration of secondary score line.
FIG. 8 is a top plan view of another form of easy opening container
constructed in accordance with the teachings of this invention.
FIG. 8a is a sectional view taken generally along line 8a-8a of
FIG. 8 with the lifting end of the tab body having been raised
slightly to illustrate the idle lift obtainable with this
embodiment of the invention.
FIG. 9 is a bottom plan view of another form of tab constructed in
accordance with the teachings of this invention.
FIG. 10 is an enlarged fragmentary sectional view taken generally
along lines 10--10 of FIG. 12.
FIG. 11 is a fragmentary elevational view of the tab looking
generally in the direction of the arrows 11--11 of FIG. 10.
FIG. 12 is a top plan view showing the tab of FIG. 9 installed on a
can end.
FIGS. 13 and 14 are sectional views similar to FIG. 2 showing the
effect of supporting the connecting wall at different
locations.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings and in particular to FIG. 1 thereof,
reference numeral 11 designates an easy opening container wall
constructed in accordance with the teachings of this invention. The
easy opening container wall 11 includes a container wall in the
form of a can end 13 constructed of sheet material such as
aluminum. The can end 13 has a primary score line 15 therein
defining a tear portion or panel 17 which is removable from the can
end 13. In the embodiment illustrated, the primary score line 15
and the panel 17 are circular in plan, it being understood that
other configurations may be utilized if desired. Although the
primary score line 15 and the panel 17 can be of any size desired,
in the embodiment illustrated the panel 17 covers substantially the
entire area in plan of the can end 13. The can end 13 has a
peripheral attaching flange 19 for attaching the can end 13 to a
can body 21 (FIG. 2).
The easy opening container wall 11 also includes a tab 23 connected
to the panel 17 by attaching means such as a rivet 25 formed
integrally with the sheet material of the panel 17. A secondary
score line 27 is formed in the panel 17 adjacent the rivet 25 as
shown in FIG. 1.
The tab 23 includes a tab body 29 and an attachment portion 31
integrally joined to the tab body by a connecting wall 33 (FIG. 2).
The tab 23 preferably integrally formed of sheet material such as
aluminum and the tab body 29 surrounds the attachment portion 31.
The tab body 29 defines an opening 35 sized to accommodate the
finger of a user. The tab body 29 is relatively rigid
longitudinally and includes a lifting end 37 and a rupturing or
nose end 39 which overlies a location 41 (FIG. 2) on the can end 13
closely adjacent the score line 15. The tab 23 is positioned
generally radially on the panel 17 with the lifting end 37 lying
radially inwardly of the rupturing end 39.
The connecting wall 33 attaches the attachment portion 31 to the
tab body 39 at a region adjacent the rupturing end 39. The sheet
material of the tab along and adjacent the connecting wall 33 is
sufficiently pliable to hingedly attach the tab body 29 to the
attachment portion 31. The construction of the tab is such as to
form a hinge line 42 (FIGS. 3 and 6). Thus, the tab body 29 serves
as a lever.
The details of the tab 23 can best be seen in FIGS. 2-4. An inner
peripheral region of the sheet material of the tab surrounding the
opening 35 is turned outwardly to form an inner reinforcing bead 43
which extends completely around the opening 35 except in the region
on the attachment portion 31. Similarly, a marginal portion of the
sheet material of the tab body 29 is turned inwardly to define an
outer reinforcing bead or curl 45 which extends substantially
completely around the outer periphery of the tab body. The lifting
end 37 of the tab body 29 has a notch 47 therein. The outer
reinforcing bead 45 is interrupted at the notch 47 and is severed
along a radial line 49 at the rupturing end 39 of the tab to
facilitate formation of the rupturing end. The bead 45 is
uninterrupted at the nose end 39 except for the radial line 49.
The connecting wall 33 slopes downwardly as shown in FIGS. 2 and 3.
The attachment portion 31 has a rivet receiving aperture 51
therein.
The sheet material at the rupturing end 39 is deformed to form a
solid rupturing element or point 53 which overlies the location 41
on the score line 15. The sheet material of the outer curl 45 at
the rupturing end 39 is used to support the connecting wall 33 as
shown in FIGS. 2 and 3. Specifically, the construction includes
first and second layers of sheet material 55 and 57 interconnected
by a bend portion 59 of the sheet material, to define a reinforcing
section of the connecting wall 33. The bend portion 59 is
engageable with a face 61 of the connecting wall 33 at a region as
close to the can end as the dimensions of the sheet material permit
to support the connecting wall 33 during use of the tab. The layers
55 and 57 support the connecting wall 33 to a greater extent than
would be possible if only a single layer were utilized for this
purpose. This also gives a greater bend radius to help avoid
fracturing.
The hinge line 42 lies substantially along the region of contact
between the bend portion 59 and the face 61. It is apparent from
FIGS. 1 and 4 that the hinge line 42 of the tab 23 lies
intermediate the rivet 25 and the rupturing end 39. Furthermore,
the hinge line 42 extends in a direction generally transverse of
the longitudinal direction of the tab 23.
The secondary score line 27 in the embodiment illustrated has a
straight line segment underlying the tab 23 and curved end portions
which terminate adjacent regions of the primary score line 15. A
central region of the secondary score line 27 substantially
underlies the hinge line 42 of the tab 23 as shown in FIG. 1. Thus,
this region of the secondary score line 27 lies intermediate the
rivet 25 and the location 41 (FIG. 2). However, as shown in FIG. 3,
the score line 27 lies intermediate the hinge line 42 and the rivet
25.
In operation of the easy opening container wall 11, the lifting end
of the tab 37 is moved away from the panel 17 to thereby pivot the
tab body 29 about the hinge line 42. This forces the rupturing end
39, and more specifically the rupturing point 53 against the
location 41 of the can end 13 to thereby stress the primary score
line 15. Continued upward movement of the lifting end 39 results in
rupture of the sheet material along the score line 15 as shown in
FIG. 6.
During and after initial rupture or breaking of the score line 15,
a segment 63 of the panel 17 is bent inwardly about a bend line
which generally lies along a central region of the secondary score
line 27. The secondary score line 27 facilitates the inward bending
of the segment 63 and makes initiation of severance of the sheet
material along the primary score line 15 easier. The sheet material
along the secondary score line 27 does not rupture during ordinary
pivotal movement of the tab body 29. The secondary score line 27
also tends to increase the length of arc of the primary score line
15 which is ruptured in response to pivotal movement of the tab
body 29. Thus, with the construction shown in FIG. 1, the primary
score line 15 would be ruptured from the location 41 outwardly to
the regions of the primary schore line 15 which are substantially
in alignment with the central portion of secondary score line 27.
If the secondary score line 27 were not provided, the initial arc
of rupture may be shorter than this for a given angular
displacement of the tab body 29. Following initiation of severance
of the primary score line 15, the user exerts an outward pulling
force on the tab body 29 to completely remove the panel 17 from the
can end 13. During tab manipulation, the layers 55 and 57 are
operative to support and strengthen the connecting wall 33. It
should be apparent that the concepts of this invention are
applicable to tabs of different construction provided that the tab
has a hinge line intermediate the rivet 25 and the rupturing end
thereof.
A preferred method for making the tab 23 is illustrated in FIG. 5.
A tab blank 65 of the desired configuration is formed in an
elongated strip of sheet material 67 by appropriately severing the
strip 67 to form a slot 69 and openings 71 and 73. The tab blank 65
is integrally connected to the strip 67 by a web 75 and the
remainder of the periphery of the tab blank 65 is separated from
the strip 67 by the slot 69. As shown in FIG. 5, the web 75 is
located centrally at the lifting end 37. The slot 69 and the
openings 71 and 73 may be formed simultaneously or sequentially at
one or more stations by suitable tooling (not shown). The strip 67
is moved between work stations by any suitable strip stock feeding
means (not shown). Subsequently, additional work operations are
performed on the tab blank 65 while the tab blank is retained in
the strip 67 by the web 75 to thereby convert the tab blank into a
tab 23' which may be identical to the tab 23. Finally, the tab 23'
is severed from the strip 67 by cutting the web 75.
With reference to FIG. 4, it can be seen that the outer curl 65 is
substantially uninterrupted except for the notch 47 which is at a
location corresponding to the web 75 when the tab was in the strip
67. The notch 47 recesses raw edges 78 and 78a to protect the user
against lacerations. The interruption of the outer curl 45 at the
lifting end 37 is the result of cutting the web 75 to free the tab
from the strip 67. Thus, the outer curl 45 is not interrupted along
the longitudinal sides of the tab body 29 where such interruption
would result in some weakening of the tab. Nor is the outer curl 45
interrupted at the rupturing end 37 as a result of carrying the tab
23' in the strip 67.
FIG. 7 shows a second embodiment of the invention and portions of
the embodiment of FIG. 7 corresponding to portions of the
embodiment of FIG. 1 are designated by corresponding reference
numerals followed by the letter a. The embodiment of FIG. 7 is
identical to the embodiment of FIG. 1 except for the shape of the
secondary score line 27a. In the embodiment of FIG. 7, the
secondary score line 27a has end portions 79 and 81 which curve
outwardly from a straight central portion 83. The end portions 79
and 81 curve away from the lifting end 37a of the tab 23a generally
toward an adjacent region of the primary score line 15a. Generally
the secondary score line 27a is shaped to conform to the bend line
which would inherently be formed in the panel 17a if no secondary
score line were provided. Except for the curved end portions 79 and
81, the positioning and configuration of the score line 27a is
identical to the positioning and configuration of the secondary
score line 27 (FIG. 1).
FIG. 8 shows an easy opening container wall 85 which represents a
third embodiment of the invention. The easy opening container wall
85 includes a container wall in the form of a circular can end 87
having a peripheral attaching flange 89 to secure the can end to a
can body (not shown). A primary score line 91 in the can end 87
defines a tear portion 93 in the can end 87. The tear portion is
elongated with the direction of elongation extending generally
radially of the circular can end 87 and the tear portion covers a
relatively small area of the can end.
A tab 95 (FIGS. 8 and 8a) is attached to the leading end of the
tear portion 93 adjacent the center of the can end 87 by a rivet 97
formed integrally with the sheet material of the can end 87. The
tab 95 includes a tab body 99 and an attachment portion 101
interconnected by a connecting wall 103. The tab 95 has a lifting
end 105 and a nose end 107 which overlies a region of the can end
87 outside of the tear portion 93. The tab 95 is preferably
identical to the tab 23 except the former has no rupturing element
or point. Rather, the tab 95 has an arcuate cam 108 at the nose end
thereof adapted to bear against the can end 87 during manipulation
of the tab. In addition the rivet 97 is spaced from the connecting
wall 103 as shown in FIG. 8a. This provides idle lift, i.e., allows
the tab body 99 to be pivoted relatively easily to the position
shown in FIG. 8a without rupturing the score line 91. Idle lift is
advantageous in allowing the user to get his finger beneath the
lifting end 105. The tab 95 also has a double layer reinforcing
section 109 substantially as described hereinabove with reference
to FIGS. 1-3.
In operation of the easy opening container wall 85, the lifting end
105 of the tab 95 is moved away from the can end 87 and during idle
lift such movement of the handle end is substantially unrestrained.
Following idle lift the nose end 107 bears on the region of the can
end 87 outside of the tear portion 93 and is given relatively rigid
support with the result that an upward lifting force is applied to
the leading end of the tear portion 93 through the connecting wall
103, the attachment portion 101 and the rivet 97. By continuing
such pivotal movement of the tab body 99, the sheet material of the
score line 91 at the leading end of the tear portion 93 will be
ruptured. A portion of the tab covers the area of initial opening
to deflect spray of the contents. Following such initial rupture,
the user exerts an outward pulling force on the tab body 99 to
thereby completely sever the tear portion 93 from the container
wall 87 to form a pouring opening.
FIG. 9 shows a tab 121 of somewhat different construction than the
tabs illustrated in FIGS. 1-8. The tab 121 includes a tab body 123
and an attachment portion 125 integrally joined to the tab body by
a connecting wall 127 (FIG. 10). The connecting portion has an
arcuate cutout 128. The tab 121 is preferably integrally formed of
sheet material such as aluminum and the tab body 123 surrounds the
attachment portion 125. The tab body 123 defines an opening 129
sized to accommodate the finger of a user. The tab body 123 is
relatively longitudinally rigid and includes a lifting end 131 and
a rupturing or nose end 133.
The tab body 123 is of less rounded appearance than the tab body 29
(FIG. 4). The tab body 123 has an inner reinforcing bead or curl
135 and an outer reinforcing bead or curl 137 which is interrupted
at the lifting end 131 and at the nose end 133 by a rupturing
flange 139. The rupturing flange 139 differs from the rupturing
point 53 (FIG. 4) in that the outer bead 133 is severed along lines
141 and 143 (FIG. 11) to thereby free the sides of the flange 139
so that it is connected to the remainder of the tab only along the
upper end thereof. The outer bead 133 also includes a double layer
portion 145 which supports the outer surface 147 of the connecting
wall in the same manner described hereinabove with reference to
FIGS. 3 and 4. The outer bead 137 is cut along a radial line 149 at
the nose end 133 as shown in FIG. 9. Accordingly, the tab 121 is
very similar to the tab 23 shown in FIGS. 3 and 4 except that the
former provides a rupturing flange 139 in lieu of the integral
rupturing point 53 of the former.
FIGS. 10 and 12 show an easy opening container wall 151 utilizing
the tab 123, it being understood that the tab may be used with easy
opening container walls of different construction than that
illustrated in FIGS. 10 and 12. The easy opening container wall 151
includes a can end 153 having a peripheral attaching flange 155 for
attaching the can end to a container body 157 (FIG. 10). The can
end 153 is constructed of sheet material such as aluminum and has a
primary score line 159 therein defining a panel 161 which is
removable from the can end 153 upon complete severance of the
primary score line.
The panel 161 covers a major portion of the area in plan of the can
end 153 and has a secondary score line 163 therein closely adjacent
and spaced radially inwardly from the primary score line 159. The
secondary score line 163 constitutes an anti-fracture score which
permits the segment of the panel 161 circumscribed thereby to flex
if the container is dropped to thereby prevent such impact from
rupturing the primary score 159. Except for a section 165 of the
score line 163, the score line 163 is spaced a constant radial
distance from the primary score line 159. Thus, except for the
section 165, the secondary score line 163 is geometrically similar
to the score line 159.
The tab 123 is attached to the panel 161 by a rivet 167 formed
integrally with the panel with the rivet 167 projecting through an
aperture 169 of the attachment portion 125. The tab 123 is oriented
radially of the panel 161 with the lifting end 131 being at an
inward position and with the rupturing flange 139 overlying a
location on the primary score line 159. Such orientation is
maintained by a dimple 168 integral with the panel 161 which
projects into the arcuate cutout 128 of the tab 121. The panel 161
has an upstanding integral rib 170 to space the lifting end 133
above the panel.
In the embodiment of FIGS. 9-12, the rupturing flange 139 projects
generally perpendicular relative to the panel 161. The thickness of
the rupturing flange 139 is greater than the width of the primary
score line 159 and a portion of the rupturing flange 139 overlies
the can end 153 outside of the panel 161. Upon raising of the
lifting end 131, the tab body 123 pivots generally about a pivot
axis 171 lying on or closely adjacent the region of contact between
the connecting wall 127 and the double layer portion 145. This
forces the rupturing flange 139 downwardly towards the can end. In
addition, the rupturing flange 139 travels back, i.e., toward the
central region of the panel 161 somewhat. The rupturing flange 139
tends to interlock with the primary score line 159. As pivotal
movement of the tab body 123 continues, the tip of the rupturing
flange 139 tends to remain interlocked with the score line and to
bend as the remainder of the rupturing flange travels back somewhat
more. Ultimately, the rupturing flange 139 applies sufficient force
to the sheet material along the primary score line 159 to rupture
the same and thereafter further pivotal movement of the tab body
123 causes inward bending of the panel 161 generally along the
section 165 of the secondary score line 163 substantially as
described above with reference to FIGS. 1-6. After initial
severance of the score line 159, the bending of the panel 163 and
of the tab body 123 about different hinge lines may cause some
additional bending of the rupturing flange 139 assuming that the
latter remains interlocked with the sheet material along the
ruptured primary score line 159.
FIGS. 13 and 14 illustrate the effect of changing the location at
which the connecting wall is supported on the amount of travel back
of the rupturing flange. FIGS. 13 and 14 show tabs 121a and 121b,
respectively, each of which is identical to the tab 121 (FIGS.
9-12) except as specifically noted herein. Similarly FIGS. 13 and
14 show can ends 153a and 153b, respectively, which are identical
to the can end 153 (FIG. 12) except as specifically noted herein.
Parts of FIGS. 13 and 14 corresponding to parts of FIGS. 9-12 are
designated by corresponding reference numerals followed by the
letters a and b, respectively.
The tab 121a has a tab body 123a and an attachment portion 135a,
the latter being attached to a panel 161a by a rivet 167a integral
with the panel 161a. The tab 121a also has a connecting wall 127a
and a rupturing flange 139a which is oriented relative to the
primary score line 159a substantially as described in connection
with FIGS. 9-12. The tab 121a has a double layer portion or
reinforcing section 145a which engages the upper end of the
connecting wall 127a. Thus, while the reinforcing section 145 (FIG.
10) engages a central portion of the connecting wall 127, the
reinforcing section 145a engages the connecting wall 127a as high
up on the connecting wall as the dimensions of the components of
the tab 121a will permit. This causes the tab to be pivotable about
a hinge line 171a which lies near the upper end of the connecting
wall 127a.
The operation of the tab 121a is the same as the operation of the
tab 121 except that the tab body 123a pivots about the hinge line
171a which is higher up on the connecting wall 127a than is the
hinge line 171. This has the effect of moving the hinge line 171a
further away from the section 165a of the secondary score line and
from the panel 161a thereby tending to increase travel back.
Accordingly, the travel back of the rupturing flange 139a is
greater than the travel back of the rupturing flange 139 (FIG.
10).
The tab 121b is identical to the tab 121 except that the
reinforcing section 145b engages the connecting wall 127b at a
lower point thereby forming a relatively low hinge line 171b. The
panel 161b is identical to the panel 161a except for the formation
of an upwardly opening rib 173 which receives a portion of the
reinforcing section 145b to thereby permit the latter to engage the
connecting wall 127b at a lower region than would be possible if
the rib 173 were not formed in the panel 161b.
The tab 121b operates in the same manner as the tabs 121 and 121a
except that the hinge line 171b is lower relative to the panel 161b
and closer to the section 165b of the secondary score line to
thereby reduce travel back of the rupturing flange 139b. The rib
173 preferably is somewhat longer than the reinforcing section 145b
and is dimensioned so as to loosely receive the portion of the
reinforcing section which is positioned therein.
Although exemplary embodiments of the invention have been shown and
described, many changes, modifications and substitutions may be
made by one having ordinary skill in the art without necessarily
departing from the spirit and scope of this invention.
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