Note: Descriptions are shown in the official language in which they were submitted.
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CUP LID HAVING TEAR-:BACK LID RETAINER
Technical Field of the Invention
The present invention relates generally to lids for beverage containers
and more specifically to lids having a tear-back drink-thru opening flap which
is securably held in an open position within a straw depression formed in the
lids.
Background of the Invention
It is well-known to provide covers for drinking containers to prevent the
spillage of the contents of the container. Many prior art covers incorporate
an opening in the top of the cover in order to allow drinking of the contents
either in the normal drinking fashion or by the insertion of a straw. Some
covers have an opening which is sealed by a depressible tab such.that when
the tab is depressed by the insertion of a straw, the opening is unsealed for
drinking the contents of the container. U.S. Patent No. 3,048,317 issued to
Cochrane et al. discloses one such lid having an opening for a straw disposed
in a depression formed in the lid with an integrally formed hinged flap in the
bottom of the depression. The hinged flap is severed from the lid about the
majority of the periphery of the flap to pivot open when a pressure is exerted
on the flap by the end of a straw. However, unless the hinged opening is
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exactly the same diameter as the straw, the fluid within the cup may spill out
the opening between the straw and the sides of the opening once the hinged
flap has been pivoted open.
Other covers utilize a releasable drinking flap in order to prevent the
sloshing of the contents out of the containers. An example of this type of
cover is disclosed in U.S. Patent 4,738,373 issued to DeFarales, which shows
a cover having a hinged tab which is defined by score Lines formed in the
cover leading from the rim of the cover to a hinge positioned in the medial
portion of the cover. A depression is formed in the cover on the opposite ofi
the
i 0 hinge from the tab, wherein the recess receives the rim portion of the tab
once
the tab is torn open and pivoted about the hinge in order to retain the hinged
tab in an open position. However, if the user desired to use a straw with a
cover of this type, the straw would have to be inserted into the opening
created by the tearing open of the hinged tab. This would create an
exceptionally large opening for a straw, allowing the straw to float about and
allowing the contents of the cup to be spilled.
In an effort to overcome the aforementioned shortcomings, other covers
have been proposed utilizing both a straw slot and a releasable flap,
depending
upon the desired use by the consumer. An example of this type of cover is
disclosed in U.S. Patent No. 4,090,660 to Schram et al., which discloses a
cup Lid having a liftable tab which snap fits on the rim of a cup with a straw
slot formed in the portion of the lid constituting the liftable tab. This
design,
however, does not include a feature incorporated into the lid which will
retain
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the liftable tab in an open position for convenient repeated drinking from the
opening created by the liftable tab.
Another example of a prior art drinking lid utilizing both a straw slot
and a releasable flap is disclosed in U.S. Patent No. 5,335,812 issued to
Boiler, which shows a lid having a straw puncturable area formed in a
rupturable depression in the lid. The lid further includes a flap defined by
lines of weakness that may be torn and pivoted to overlie a central portion of
the lid to retain the flap in an open position. Of course, designs of this
general type forming a retaining portion in the center of the lid to hold the
flap open as well as forming a separate rupturable depression for a straw are
difficult to mold due to the number of depressions and features which must be
formed in the cup lid.
Yet another type of prior art drinking lid utilizing both a straw slot and
a releasable flap is disclosed in U.S. Patent No. 3,994,411 issued~to Elfelt
et
al., which shows a lid having a foldback drink opening. A pull tab formed
on the edge of the rim of the foldback portion is insertable in a straw slit
formed in the lid in order to hold the foldback portion in an open position.
This foldback drink opening requires a great amount of attention by the user
to insert the pull tab into the narrow straw slot in order to hold the
foldback
portion of the lid open. Furthermore, since the straw slot must be forced open
to receive the pull tab, the straw slot will be slightly ajar when retaining
the
pull tab which can allow the contents of the cup to spill therethrough.
Clearly, there is a need for a drink-thru cup lid which provides both a
straw slot and a tear-back flap which is simple to form and which does not
a
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require multiple separate components to be formed in the lid for each drink-
thru feature. Moreover, 'there is a need for a drink-thru cup lid which
securably retains the tear-back flap in place within the straw slot depression
without rupturing the cup lid in the straw slot area.
Surnman~ of the Invention
According to one aspect of the invention there is provided a disposable
iid for a drinking cup that includes a substantially planar cover portion and
an
annular mounting portion surrounding a periphery of the planar cover portion
for
sealingly engaging the drinking cup. The annular mounting portion includes a
downwardly extending annular skirt. A tear-back section extends from the
annular skirt to a medial portion of the lid and is formed within a quadrant
of the
annular mounting portion and the planar portion. A raised protrusion extends
firom an upper surface of the tear-back section of the lid and has a
circumferential dimension less than a corresponding circumferential dimension
of ' '
the tear-back section. A hinge region is located in the said quadrant of the
planar cover portion and a depression is formed in the quadrant on an opposing
side of the hinge region from the raised protrusion. The depression has an
inner
surface extending from the planar cover portion to a bottom surface and the
depression has a circumferential dimension equal to or less than the
2d circumferential dimension of the protrusion, such that the tear-back
section of
the lid may be displaced from the lid and pivoted about the hinge region until
the circumferential dimension of the raised protrusion is received within the
circumferential dimension of the depression, the protrusion frictionally
engaging
the inner surface of the depression to retain the tear-back section of the lid
in
an open position.
a
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Another aspect -of the invention provides a disposable tid for a drinking
cup comprising a substantially planar cover portion including a first
substantially
horizontal plane and a second substantially horizontal plane. An annular
mounting portion surrounds a periphery of the planar cover portion for
sealingly
engaging the drinking cup. The annular mounting portion includes a downwardly
extending annular skirt and a tear-back section extends from the annular skirt
to
a hinge region located in a medial portion of the lid. A raised protrusion
extends
from an upper surface of the tear-back section of the lid and has a
circumferential dimension less than a corresponding circumferential dimension
of
1 ~. ~ the tear-back section. A depression is formed in a medial portion of
the lid on
an opposing side of the hinge region from the tear-back section so that the
ear-back section of the lid may be displaced from the lid and pivoted about
the
hinge region until the circumferential dimension of the raised protrusion is
received within the depression. The raised protrusion, the hinge region, the
depression and the tear-back section of the lid are formed in the second
horizontal plane of the planar cover portion positioned lower than the first
horizontal plane.
These, as well as additional objects of the present invehtion will become
apparent from the following detailed description when read in light of the
severaf
figures.
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Brief Description of the Drawinss
Fig . 1 is a perspective view of a lid in accordance with the present
invention.
Fig. 2 is a perspective view of the lid illustrated in Fig. 1 with an
opening formed by tearing back a portion of the lid.
Fig. 3 is a top plan view of the lid illustrated in Figure 1.
Fig. 4 is a cross-sectional side view of the lid of Fig. 1 taken along line
IV-IV of Figure 3.
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Fig. 5 is a cross-sectional side view of the lid of Fig. 4 in a stacked
relationship with another lid.
Fig. 6 is a cross-sectional side view of the mold used to form beads in
the skirt of the lid of Figure 1.
Fig. 7 is an enlarged, cross-sectional side view of the area A of the
mold of Fig. 6.
Fig. 8 is a cross-sectional side view of the mold used to form the lid of
Figure 1..
Detailed Descriptionl"of the Preferred bodiment
The present invention is generally embodied in a lid 10 for a drinking
cup 12. The lid 10 may be used with cups of various types, and is
particularly suitable for use with disposable cups of the type commonly used
as carry-out containers for beverages such as coffee and the like. Such cups
are commonly made of StyrofoamTM or paper. The drinking cup 12 has a
generally circular upper lip or rim 14 with a bead formed on it for receiving
and securing the lid 10 thereon.
Referring now to Figures 1, 2, and 3, the lid 10 of the present
invention is illustrated. The lid 10 provides a cover for the cup 12 which
inhibits spillage and reduces heat transfer between the beverage and the
surrounding atmosphere. The lid 10 is secured in place on the cup 12 by an
annular mounting portion 16 which engages the rim or lip 14 of the cup 12,
wherein the annular mounting portion 16 includes a downwardly extending
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skin 17 which forms the outer peripheral circumference of the lid 10. A
portion 18 of the lid 10 may be torn back to provide an opening 20 in the lid
to enable drinking from the cup 12 without removal of the lid 10. The lid
also includes a straw slot opening 22 which functions as a means for
5 facilitating the insertion of a drinking straw (not shown) into the cup 12
for
withdrawing liquid by suction.
A central raised portion 24 is formed about a substantial portion of a
medial area within the circumference of the lid 10 with an upstanding annular
wall 26 forming the side surfaces of the central raised portion 24. Bridging
10 the space between the mounting portion 16 and the upstanding annular wall
26
is an annular channel 28 which readily receives any fluid which may flow out
of the opening 20 when the container is jarred or which may spill during
consumption of the container. As can be seen from Figs. 1 and 2, the annular
channel 28 is significant in size to accommodate more than just a few droplets
of fluid.
In the preferred embodiment of the present invention, the tear-back
portion 18 of the lid 10 and the straw slot opening 22 are formed in a medial
portion of the lid which is not raised, wherein the non-raised medial portion
is surrounded on three of its sides by central raised portion 24. The straw
slot
opening 22 is formed radially inward of the tear-back portion 18 of the lid
10,
wherein the tear-back portion 18 of the lid 10 includes a protrusion 30 which
extends from the upper surface of the lid 10. The tear-back portion 18 of the
lid 10 extends from the annular mounting portion 16 to a trough 32 formed
radially inward of the annular mounting portion 16 between the protrusion 30
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and straw slot opening 22. The trough 32 serves as the pivotal hinge axis for
the tear-back portion l8.of the lid 10, so that, as the tear-back portion 18
is
torn away from the remaining portion of the lid 10, the tear-back portion i 8
will rotate away from the brim 14 of the cup I2 while pivoting about trough
32.
A flange 34 extends from the edge of the skirt I7 away from the cup
I2 on the tear-back portion 18 of the lid 10 to provide a gripping surface for
a consumer to grasp and pull in order to tear open tear-back portion 18. In
order to facilitate tearing; a pair of cuts 37 rraay be formed through the
skirt
17 adjacent to flange 34 to provide a starting point for tearing open tear-
back
portion 18. In an alternative embodiment of the present invention, a plurality
of corrugations 36 may be formed on both sides of protrusion 30, as shown
in Fig. 3, to direct the tearing of tear-back portion 18 in a predetermined
manner and prevent accidental and random tear directions to be assumed. The
i 5 corrugations 36 preclude random tearing by the fact that the lid structure
is
extremely rigid across the corrugated sections 36 and weak only on the precise
line at which the corrugations 36 stop. Therefore, a sharp and accurate tear
line is provided along the edge 38 of the corrugations 36 without the
disadvantages of a score Iine which is the most frequently used tear inducing
means. The formation of corrugations 36 in the lid 10 provides a simple and
efficient method of producing an accurate tear line since the corrugations 36
can be formed along with the rest of the lid 10 and delicate tool adjusting is
not required as is required with a scoie line to avoid cutting through the lid
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material if the score is too deep or forming an inadequate score line if too
shallow.
The straw slot opening 22 is formed in a depression 40 within the lid
10, wherein the depression 40 facilitates the receipt of the end of a straw
(not
shown) in the straw slot opening 22 as the opening to the depression 40 in the
top surface of the lid 10 is larger than the diameter of the straw. The
depression 40 includes a pair of sloping side walls 42 and 44 which extend
from the top surface of the lid 10 toward a frangible junction 46 at the
bottom
of the depression 40, so that the depression 40 has a V-shaped or triangular
cross-sectional shape, as can be seen from Fig. 4. The thickness of the lid
material at frangible portion 46 is thinner than the lid material in the other
portions of the lid 10 to allow frangible portion 46 to be ruptured by the
force
exerted by the end of a straw as it is inserted into straw slot opening 22. As
a straw is inserted into straw slot opening 22, the tapered shape of the
depression 40 causes the circular shape of the end of the straw to flatten
until
the end of the straw deforms into a V-shaped cross-sectional shape similar to
that of the depression 40. Therefore, the end of the straw is deformed into a
point as it progresses into depression 40 which acts to assist in piercing
frangible portion 46 in addition to the force applied by the straw pushing
side
walls 42 and 44 away from oneanother. The side walls 42 and 46 further
extend between end walls 48 and 50 in depression 40, wherein end walls 48
and 50 prevent against extended fracture, cracking or tearing of the frangible
junction 46 which may be caused by the insertion of the drinking straw into
the straw slot opening 22. Due to the V-shaped configuration of the
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depression 40, a momentary countering force is created to center the straw
over the frangible portion 46 by side walls 42 and 44. If the force used to
insert the straw is excessive, the end walls 4$ and 50 provide a structure
which redirects and absorbs the tearing forces to prevent extended tears
across
the lid 10. The momentary excessive force will be absorbed by the end walls
48 and 50 such that the radial propagation of the tear will reach the end
walls
48 and 50 which causes the radial force to be redirected upwardly which
prevents continued tearing of the frangible juncture 46.
The frangible portion 46 is formed at substantially the same time as the
remaining structural portions of the lid configuration. That is, a sheet of
thermo-deformable material, such as thermoplastic, is placed in a
predetermined position with respect to a die element in a known manner for
forming lids of this nature. The thermo-deformable material is either
previously heated or subsequently heated to a deformable temperature and then
vacuum formed over the die element. A suction device draws the thermo-
deformable material into a depression in the die element to form depression
40, wherein the thermo-deformable material is drawn into the depression until
the desired thickness of the material forming frangible portion 46 at the
bottom of the depression is achieved. Therefore, frangible portion 46 is
formed at the same time as the rest of the lid configuration without the need
for delicate tool adjusting to provide the proper scoring in the lid material
as
is usually done when forming straw slots. Furthermore, since frangible
portion 46 is integrally formed with the rest of the lid 10, the lid 10 has no
openings where the contents of the cup 12 can spill out if the cup 12 is
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advertently knocked over. While the depression 40 is described above as
having a V-shaped cross-sectional shape, it is understood that the depression
40 may comprise any shape which allows the straw slot opening 2? to function
with the goals and objectives of the present lid configuration as described
herein.
Once frangible junction 46 is broken by the end of a straw, the side
walls 42 and 44 of depression 40 are separated from oneanother and allow the
straw to travel into the cup 12 between the side walls 42 and 44. As the straw
passes between side walls 42 and 44, the side walls 42 and 44 bend around the
straw to conform to the shape of the straw. Therefore, the side walls 42 and
44 provide a close engagement around the inserted straw, which acts to seal
the cup lid 10 around the straw to prevent the contents of the cup 12 from
spilling out of the straw slot opening 22 between the straw and side walls 42
and 44. Additionally, each of side walls 42 and 44 included guides 43 and 45,
respectively which aid the consumer in inserting the straw into the depression
40.
The protrusion 30 is shaped such that when the tear-back portion 18 of
the lid 10 is opened and pivoted about hinge 32, the protrusion 30 is received
within depression 40 to retain the protrusion in an open position, as shown in
Fig. 2. The width of protrusion 30 is slightly larger than the width of
depression 40, resulting in the end walls 48 and SO frictionally engaging the
end surfaces 52 and 54 of protrusion 30 to hold the protrusion within
depression 40. In order to be received within depression 40, protrusion 30
includes sloping side surfaces 56 and 58 of a substantially similar slope to
that
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of sloping side walls 42 and 44 of depression 40, wherein sloping side
surfaces 56 and 58 rest adjacent to sloping side walls 42 and 44,
respectively,
when protrusion 30 is inserted into depression 40. In the preferred
embodiment of the present invention, protrusion 30 has a substantially
trapezoidal cross-sectional shape, as illustrated best in Fig. 4. However,
protrusion 30 may be triangular or any other shape which allows the
protrusion to be positioned within depression 40 without rupturing frangible
juncture 46.
By forming protrusion 30 having a substantially similar shape as
depression 40, the protrusion 30 will not engage the sloping side walls 42 and
44 of depression 40 and cause frangible juncture 46 to be broken. Therefore,
the straw slot opening 22 remains unaffected and frangible juncture 46 remains
intact when the straw slot depression 40 is used to retain the tear-back
portion
18 of the lid 10 in an open position. Even if frangible juncture~46 is broken
by inserting a straw into depression 40, end walls 48 and 50 of depression 40
will still function equivalently by frictionally engaging protrusion 30 to
retain
the tear-back portion 18 in the open position. Accordingly, the prior use of
one of the drink-thru features of the lid 10 will not affect later use of the
other
drink-thru feature by a consumer.
A recess 60 is also formed in the lid configuration radially inward of
the depression 40 for receiving the mounting portion 16 of the lid 10 when the
tear-back portion 18 is retained in its open position. The lid configuration
is
further designed such that a plurality of lids 10 may be positioned together
in
a stacked relationship, as shown in Fig. 5.
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In one embodiment of the lid configuration of the present invention, a
plurality of inwardly projecting interrupted beads 62 are formed about the
periphery of the skirt 17 to assist in retaining the lid 10 on the rim 14 of
the
cup 12. The beads 62 extend radially inward further than the remaining
portions of skirt 17, causing the mounting portion 16 of the lid 10 to engage
the rim 14 of the cup 12 more tightly in the portions of the skirt 17 where
the
beads 62 are formed. This causes a greater frictional engagement between the
lid 10 and the rim 14 of the cup 12 at beaded portions 62 which assists in
retaining the lid 10 on the rim 14 of the cup 12. Greater frictional
engagement between the lid 10 and cup 12 is especially useful in retaining the
lid 10 in place when an upward force is applied on flange 34 to tear open tear-
back portion 18. For this reason, beads 62 of a first predetermined length are
formed in the skirt 17 at least on both sides of tear-back portion 18 to
retain
the lid 10 on the rim 14 of the cup 12 as a force trying to remove the lid 10
will be exerted on that area of the lid 10 when tear-back portion 18 is
opened.
Furthermore, two spaced-apart beads 64 of a second predetermined length,
shorter than the beads 62 of the first predetermined length, are formed in the
skirt 17 connected to tear-back portion 18. The beads 64 assist in retaining
the tear-back portion 18 of the lid 10 on the rim 14 of the cup 12, especially
when closing tear-back portion 18 after it has already been opened.
Fig. 6 shows a cross-sectional view of a die element 70 which may be
used to form the interrupted beads 62 and 64 of the lid illustrated in Fig. 1.
This die ?0 is used along with otherwise conventional thermoforming
equipment in a lid thermoforming process such as is conventionally performed
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to create the remaining features molded into the plastic disposable cup lids
10.
Further, the die 70 may be readily added to the present thermoforming cup
dies for the formation of disposable cup lids. The die 70 includes an outer
circumferential projection 72 which is used to form the mounting portion 16
and skirt 17 of the lid 10. Fig. 7 shows an enlarged view of area A on the
circumferential projection 72 of Fig. 7. The projection 72 includes a
plurality
of indentations 74 which are used to form interrupted beads 62 and 64,
wherein vacuum passageways 76 are formed in the die 70 extending from
indentations 74 to a suction device (not shown} to draw the thermo-deformable
material in the indentations 74.
Fig. 8 shows a die element 80 which may be used to form the
remaining portions of the lid configuration of the present invention, wherein
die element 80 may be used in conjunction with die element 70 to form lid 10.
The die 80 includes recess 82 designed to form straw slot depression 40,
wherein a groove 84 is formed at the bottom of recess 82 to form frangible
portion 46. A vacuum passageway, similar to that of vacuum passageway ?6,
is formed at the nadir of groove 84 to draw the thermo-deformable material
into recess 82. The die 80 also includes recesses 86 and 88 to form trough 32
and recess 60 in the lid 10, respectively. Additionally, die 80 includes an
aperture 90 for receiving an alignment projection 78 from die 70 in order to
ensure the interrupted beads 62 and 64 are formed in the proper locations with
respect to the remaining features of the lid formed by die 80.
As can be seen from the foregoing, a cup lid formed in accordance with
the present invention provides a simpler structure to manufacture due the
straw
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slot depression 40 serving dual functions of providing a straw slot opening as
well as retaining the tear-back portion 18 of the lid in an open position.
Therefore, only one depression needs to be formed in the cup lid to
accomplish both functions. Furthermore, forming a .cup lid in accordance with
the present invention provides a straw slot and tear-open flap which can be
molded at substantially the same time as the remaining features of the lid
without the need for precise tooling to perform scoring in the lid.
While the present invention has been described with reference to a
preferred embodiment, it should be appreciated by those skilled in the art
that
the invention may be practiced otherwise than as specifically described herein
without departing from the spirit and scope of the invention. It is,
therefore,
to be understood that the spirit and scope of the invention be limited only by
the appended claims.
