Note: Descriptions are shown in the official language in which they were submitted.
CA 02635326 2012-05-04
LID AND CONTAINER
[0001] This application is based on, and claims priority to, U.S. patent
publication
no. 2007/0205196, having a publication date of September 6, 2007, and which
issued as
U.S. Patent No. 7,963,419, having an issuance date of June 21, 2011; and U.S.
patent
publication no. 2008/0230550, having a publication date of September 25, 2008.
FIELD OF THE INVENTION
[0002] The invention is related to containers and the associated lids, wherein
the
lids provide a seal that reduces or eliminates the need for a gasket.
BACKGROUND OF THE INVENTION
[0003] The invention, as outlined in the following narrative, is a variation
of a
molded plastic industrial container of a type in common usage today for the
containment
and shipping of various substances including, but not limited to, foods and
foodstuffs,
paints, oils, solvents, and other industrial chemicals. Generally, the
container and lid are
injection molded from a commodity plastic compound such as high density
polyethylene
or polypropylene and typically utilize a gasket of compressible foam or rubber
between
the contact surfaces ofthe pail and coyer to form a liquid tight seal.
Containers of this
type typically fall within the capacity ranges of 1 gallon up to 10 gallons.
[0004] FIG. I depicts a prior art pail and lid. The general container
configuration in
common usage today is comprised of a wide mouth pail commonly referred to as
an
"openhead" pail, and a lid which affixes over the pail opening. Installation
of the lid I is
accomplished by applying axial pressure to the top of the lid, forcing its
mechanical
latching features to expand radially over corresponding latching features on
the pail until
it locates axially into its final position and the latching features relax
into corresponding
undercuts in the pail exterior. It is noted that the term "pail" is used
broadly herein and
does not necessarily require that the item has a handle.
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[0005] The lid 1 exterior is generally comprised of a recessed center panel 6,
a
raised channel 7 designed to straddle the top of the pail sidewall, and an
outer skirt 24
having a tear strip 8 that extends downward below the level of the panel 6.
The pail
exterior is generally a tapered cylinder typically having a series of
satellite rings 3, 4, 5
around its upper half that may provide additional stiffness to the pail
opening and protect
the container in the event of a side-oriented drop. These satellite rings may
be simple
single ribs of plastic extending radially from the pail wall 3, 4 or they may
be more
geometrically complex rings 5 honeycombed with internal rib structures to
provide even
more stiffness. Additionally, the pail opening is topped by a thicker, rounded
ring or lip
9. In a gasketed container, this pail lip provides both the pail component of
the main
pail-to-cover latching mechanism and the sealing surface that interfaces with
the
compressible foam gasket.
SUMMARY OF THE INVENTION
[0006] Embodiments of the disclosed invention include a lid for a container
that
reduces or eliminates the need for a gasket by providing a series of seals.
The first seal is
a cork seal mechanism that is forced against the container interior at a top
portion of the
container. The second seal is created by at least two ribs that create a
spring-like force
against the pail, preferably at the pail lip. As used herein "lip" refers to
any top edge of a
container. Such edges may be for example, greater in thickness than the
container wall,
of equal thickness or of a rolled configuration. An additional seal may be
incorporated
that includes a skirt having a tear strip. The skirt has a first hook above
the tear strip that
will engage the pail lip or a rib on the pail after the tear strip is removed.
A second hook
is position on the tear strip and engages a rib on the pail below the lip or
rib to which the
first hook engages. This hook is engaged when the tear strip is in place.
[0007] In a further illustrative embodiment of the invention, the lid contains
a
substantially u-shaped circumferential protrusion extending downward from the
lid top
portion with the opening of the "u" facing downward. This u-shaped protrusion
serves as
a cork seal mechanism. The first and second ribs are between the u-shaped cork
seal
mechanism and the lid side portion. This u-shaped protrusion may also provide
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additional support to a container/lid combination on which it is used. A
latching
mechanism, such as a bead may extend from the u-shaped protrusion to engage
the inner
surface of a container wall.
[0008] In yet a further embodiment of the invention, the ribs of the second
seal
are of different flexibility or stiffness. When the lid is positioned on the
container, one or
more flexible ribs are forced against one or more rigid ribs.
[0009] These and additional aspects of the invention will be discussed in more
detail below.
DESCRIPTION OF THE DRAWINGS
[00010] The invention is best understood from the following detailed
description
when read with the accompanying drawings.
[00011] Figure 1 depicts a prior art pail and lid.
[00012] Figure 2 depicts a cutaway of a lid according to an illustrative
embodiment
of the invention.
[00013] Figure 3 depicts a cross section of a lid a according to an
illustrative
embodiment of the invention.
[00014] Figure 4 depicts a cross section of a lid- in position on a pail a
according to
an illustrative embodiment of the invention.
[00015] Figure 5 depicts a lid and pail showing a tear strip a according to an
illustrative embodiment of the invention.
[00016] Figure 6 depicts a cross-section of a lid according to another
illustrative
embodiment of the invention.
[00017] Figure 7 depicts a cross-section of the lid of Figure 6, secured on a
container according to an illustrative embodiment of the invention.
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[00018] FIG. 8 depicts a lid according to a further illustrative embodiment of
the
invention.
[00019] FIG. 9 shows an illustrative embodiment of the lid of FIG. 8
positioned
on a container.
[00020] FIGS. 10 and 11 show various measurements for a lid and container
combination such as depicted in FIGS, 6 and 7.
[00021] FIG. 12 depicts the container and lid of FIGS. 1-5 and shows various
measurements.
DETAILED DESCRIPTION OF THE INVENTION
[00022] An illustrative embodiment of the inventive pail and lid is shown in
FIGS.
2-5 as a wide mouth pail. This illustrative embodiment incorporates features f
the prior
art pail shown in FIG. 1. The exemplary embodiment of FIGS. 2-5 eliminates or
reduces
the need for a compressible gasket, utilizing instead distinct plastic-to-
plastic sealing
mechanisms in combination with a unique latching arrangement to effect a
liquid-tight
seal. First, a circumferential plastic rib 10 extends downward from the
underside of the
lid 1. The outer diameter of this rib is tapered and stepped such that, during
lid
installation, it initially clears the inner pail side wall 16. As the lid is
pressed into its final
position, the outer diameter of the rib 10 transitions to a larger diameter
surface 18 that
forms an interference fit with the inner pail wall 16, creating a plug seal
similar to that of
a cork in the neck of a bottle. Second, two thin, tapered circumferential ribs
11, 12 extend
downward, preferably at outwardly sloping angles from the underside of the
lid's channel
7, the outermost of these ribs 12 being somewhat shorter than the innermost
rib 11. When
the lid is pressed into the latched position on the pail, the innermost rib
contacts the top
surface 14 of the pail lip 9 and is deflected upward and outward, placing the
rib material
in tension and forming a compressive plastic-to-plastic seal with the top
surface 14 of the
pail lip 9. Near the end of its deflection, the longer innermost rib 11
contacts the shorter
outermost rib 12, deflecting it also in an outwardly direction. The resulting
reciprocal
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force applied by these ribs in combination against the top surface 14 of the
pail lip 9
assures continuous plastic-to-plastic contact, forming a liquid tight
secondary seal.
Lastly, the inner surface 13 of the outermost wall of the lid is sized such
that it is of a
diameter smaller than that of the outer surface of the pail lip 15. As the lid
1 is pressed
into its final position, this outer lid wall 13 stretches over the outer lip
surface 15 of the
pail, effecting a tertiary liquid tight seal. The integrity of these three
unique sealing
mechanisms in combination has been proven liquid-tight under multiple test
conditions.
[00023] The method of latching this lid to the container is also somewhat
unique,
and driven, in part, by the requirements of the sealing mechanisms as listed
above. In a
typical plastic openhead pail and lid assembly, as commercially available
today, the
primary latching mechanism is a large hook, or undercut, molded as part of the
inner wall
of the cover's outermost diameter, which deforms during lid application until
it passes the
pail lip, at which point it relaxes back into shape below the pail lip,
securing the lid to the
pail. Typically these lids are segmented to facilitate removal, as each
segment must be
pried away from the pail in series in order to release the hook and remove the
lid.
[000241 To effect the interference seal between the inner cover surface 13 and
outer pail lip surface 15, it is necessary for the cover's outer wall to form
a continuous
and unbroken surface. This precludes the segmentation of this wall to
facilitate cover
removal by the end user as is done in a typical openhead pail lid. The
gasketless
container, therefore, relies on non-traditional latching techniques.
[00025] Embodiments of the gasketless container utilize two latches, primary
and
secondary mechanisms, to affix the lid to the pail and a removable
circumferential tear
strip 8 to facilitate the initial opening of the container. Tear strip 8 is
removable from lid
I at a point between hooks 19 and 20. The primary latch mechanism, used for
the initial
lid application by the filler, consists of a circumferential hook feature 19
located far down
the inside of the outer wall of the lid which interfaces with the topmost
satellite ring 3 of
the pail.
[00026] As the lid is applied to the pail, the cover hook 19 is forced to
expand over
the pail's ring 3 until it snaps past said ring and locks into place below it,
securing the lid
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to the pail. The secondary latch, useful only for resealing of the container
after the initial
opening, consists of a much smaller hook 20 located farther up on the inside
of the outer
lid wall which, in application, deforms around and snaps under the pail lip 9.
[000271 This highlights one of the key differences between the gasketless pail
and
traditional pails. Where traditional containers may have satellite rings to
add stiffness and
improve drop performance, the uppermost ring on the gasketless pail is used as
a latching
feature and its location relative to the corresponding latching feature on the
lid is
important to performance of the seal mechanisms.
[000281 In use, the pail and lid function as follows:
= The open pail 2 is filled with its contents.
= The lid 1 is placed upon the pail 2 and pressure is applied to force it
into its final position. At this point, both the primary 19 and secondary
20 latches have snapped into position and all sealing mechanisms are
effectively compressed.
= The container is shipped to its retail or wholesale outlet where it is
purchased by the end user.
= The end user opens the container by gripping the tear tab 17 and
removing the bottom skirt section 8 from the lid, effectively removing
the primary latching mechanism.
= The lid may now be removed by gently prying the remainder of the lid
from the pail.
= The lid may now be reapplied to the pail by means of hand pressure
and the secondary hook becomes the primary latching feature.
[000291 The invention will now be described more generally including various
embodiments. Lid I commonly has a top portion, such as center panel 6, and a
side
portion 22 extending downward with respect to the top portion along the
perimeter of the
top portion or from the top edge portion. The term "downward" as used herein
does not
necessarily indicate a direction perpendicular from the lid top portion, but
instead is used
in a more general manner to indicate toward ground level when the container is
in an
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upright position. As used herein "top edge portion" refers to an area at or
near the
perimeter of the lid. The top portion of the lid is disposed over the opening
of the
container and may extend further outward. The side portion extends from the
top portion
downward along a portion of the sidewall of the container. The top portion may
include
a channel, such as the u-shaped latching channel 7 shown in FIGS. 2-4. The u-
shaped
latching channel may have a curved upper portion as shown in the figures, or
have a flat
top with channel walls substantially perpendicular thereto. Various channel
profiles are
included in the scope of the invention, provided they are suitable to
accommodate the
features of the invention.
[000301 The lid provides its superior sealing qualities by incorporating a
number of
features, including protrusions extending from the underside of the lid's top
portion. A
cork seal circumferential flap, such as part 10 in FIG. 3, protrudes from the
underside of
the top lid portion such that when the lid is placed on a container the cork
seal flap is
forced against an interior wall of the container.
[000311 A first circumferential rib, such as component 11, and a second
circumferential rib, such as component 12, each extend from the underside of
the top lid
portion such that when the lid is placed on the container the first rib is
deflected toward
and contacts the second rib and the second rib is deflected toward and
contacts the
container. FIGS. 3 and 4 depict ribs 11 and 12 deflecting outwardly. It is
noted,
however, that this secondary seal can also be accomplished by one or both of
the first and
second ribs deflecting inwardly or one deflecting inwardly and the other
outwardly,
provided there is a spring-like force exerted on at least one rib against the
container. FIG.
4 depicts the second rib as shorter than the first rib. Depending on the
various
parameters, such as position of the ribs, deflection direction and lid
materials, the first rib
may be shorter than the second rib or they may be the same size. Different
thicknesses
and profiles may also be used to achieve the desired spring-like force that
facilitates the
sealing property. Additional ribs can be incorporated into the structure to
provide extra
force for the multi-rib seal or to provide further seals.
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[00032] An additional seal may be provided by incorporating a skirt with
hooks,
such as component 24, wherein the skirt has a tear strip, such as component 8.
The skirt
or lid side portion has two hook closures, such as hooks 19 and 20 (see FIG.
4), extending
from the inner surface of the skirt. The hooks latch onto protrusions on the
container,
such as satellite rings 3, 4 and 5, and lip 9. FIG. 4 depicts a larger hook 19
that engages
pail ring 3, and a smaller hook 20 that engages lip 9 after the tear strip is
removed. The
design shown in FIG. 4 is applicable to the most common pail types on the
market that
have one or more rings already incorporated into the pail design for
stability.
[00033] Accordingly, this embodiment of the invention utilizes the existing
structural rings. Rings can be incorporated into the pail design specifically
to engage the
hook, thereby providing additional options. For example, the hooks need not be
single
fully circumferential hooks, but may be comprised of a group of protrusions at
the same
height around the pail that can each engage the rib on the pail. It is also
possible for the
pail rib not to be a single fully circumferential rib. Generally, for
manufacturing reasons
and ease of lid placement, circumferential ribs and hooks are preferred.
[00034] FIG. 6 depicts a cross-section of a lid according to a further
illustrative embodiment of the invention. Cross-sectional FIG. 7 shows the lid
of FIG. 6
positioned on a container according to an illustrative embodiment of the
invention. In
this embodiment, rib 111 is significantly flexible compared to rib 112. Rib
ill's
flexibility creates a spring-like action against the more rigid rib 112. The
stiff second rib
1] 2 limits the flexure of rib I1 I to inhibit permanent deformation of rib
I11. When the
lid is placed on the container or containers are stacked, for example,
considerable stress
can be exerted on the ribs. If the ribs are allowed to flex too much, they may
permanently deform, which will negatively affect the integrity of the seal.
For most
applications, a single flexible rib and a single stiff rib that remains
substantially non-
deflected when the lid is secured on the container, will provide adequate
protection
against permanent deformation of the engaged sealing rib 111. However, it is
within the
scope of the invention to have more than one of each type of rib. It is also
possible to
have a series of ribs with varying flexibility. The choice of number,
dimensions,
location, and flexibility of ribs will depend on one or more of such factors
as the inherent
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stiffness of the materials used, lid/container application, and the size and
shape of the lid
and container.
[00035] FIGS. 6 and 7 also depict an illustrative embodiment of a u-shaped
support member 126 incorporated into the lid. U-shaped support member 126
provides
additional support to a container/lid combination on which it is used. It also
provides a
spring-like force against the interior side wall of container 102 at position
118 to serve as
a cork seal. The u-shape may provide additional force against the container as
compared
to that of rib 10 shown in FIG. 3,. In the illustrative embodiment of FIGS. 6
and 7, u-
shaped support member 126 extends downward from an outer edge of the lid top
panel
106. The embodiment depicted in FIGS. 6 and 7 also shows a portion of u-shaped
member 126 extending upward from the outer edge of lid top panel 106. This
extension
is not necessary, but may add to the structural reliability of the lid. In
this embodiment,
the top surface of the lid extends roughly perpendicular from or near the top
of a first leg
of u-shaped support member 126, and a latching mechanism extends from the
second leg
of u-shaped support member 126. U-shaped member 126 can help cushion side
impacts
and improve drop performance. The particular dimensions and material of u-
shaped
support member 126 will, at least in part, determine the extent of support and
improved
performance achieved.
[00036] FIGS. 6 and 7 show a tear strip 108. A portion of lid 101 immediately
above tear strip 108 contains one or more windows 130 that extend to tear
strip 108.
When tear strip 108 is removed, windows 130 form slits in the remaining lid
skirt 132.
The lid can then be plied off the container, for example by inserting a
screwdriver
beneath skirt 132. Other tear strip configurations are within the scope of the
invention
provided they create an adequate sealing or fastening mechanism.
[00037] Yet another sealing mechanism is shown in the illustrative embodiment
depicted in FIGS. 6 and 7. This seal is created by the interface of the inner
surface 113 of
the side portion of container lid 101 and the outer surface of container lip
109. Container
lip 109 also engages hook 134 to secure lid 101 onto container 102. The
particular
dimensions of hook 134 will depend at least in part on one or more factors
such as
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container lip characteristics, container and lid materials and application of
the container
and lid.
[00038] Various sealing mechanisms have been depicted in FIGS. 1-7, such as
those shown within channels 7 and 117. It is in the spirit and scope of the
invention to
mix and match these features to attain the most desirable container and lid
characteristics
for a particular application.
[00039] FIGS. 8 and 9 show a further illustrative embodiment of the invention
that
incorporates features shown in FIG. 3 and FIG. 6. This embodiment includes the
flexible
ribs 11 and 12 shown in FIGS. 3 and 4 but lacks u-shaped support member 126
diagramed in FIGS. 6 and 7. It also incorporates tear strip 108 and a latching
interface
between container lip 109 and rib 134 on the lid side portion as shown in
FIGS. 6 and 7.
[00040] FIG. 10 shows sealing interfaces for a container and lid of the design
shown in FIGS. 6 and 7. In an exemplary embodiment of the invention, the
interference
segment between the inner container wall and a bead 136 on u-shaped member
126,
shown at 138, is in the range of about 0.015 inches and about.035 inches. The
diameter
of bead 136 can be chosen to attain an interference fit in this range. This
illustrative
interference segment length is applicable to a lid having an outer diameter in
the range of
about 11 inches to about 13 inches. A lid of that diameter is generally used
on containers
with volumes in the range of about 3.5 gallons to about 7.0 gallons. Any of
the
interference ranges provided herein should be scaled according to the
container size, with
greater interference lengths generally necessary for larger volume containers.
All ranges
provided are particularly applicable for container and lid sizes described
above.
[00041] The interference fit is important for each sealing mechanism. In an
exemplary embodiment of the invention, the inner diameter of the cover is
sized to create
an interference fit , also called a stretch fit, with the outer diameter of
the container lip
(shown at position 140 on FIG. 10) in the range of about 0.010 inches to about
0.030
inches,
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[00042] The seal diameter, i.e. the distance from the tip of sealing rib 111
at one
point on the container circumference to the tip of sealing rib Ill on the
direct opposite
side of the container (see location 160 on FIG. 11), as measured without the
lid being on
the container, must exceed the diameter of the container taken at the apex 142
of
container lip 109, by a minimum of about 0.020 inches per side so that it will
always
deflect outward during coyer installation.
[00043] Dimensions associated with ribs Ill and 112 are also important to
achieve
a desirable seal. The seal stop height 146, i.e. the distance from the bottom
most point of
rib 112 and the top of rib 112 is preferably in the range of about 0.10 inches
to about 0.15
inches. Seal stop heights in this range will allow the coyer to be pressed
onto the
container approximately 0.03 inches past the point where the hook (such as rib
134)
engages with the container lip before the flap seal (rib 111) meets the seal
stop (rib 112).
Reference number 145 shows the face of from which rib 112 protrudes (the top
of rib 112)
to the apex 142 of container lip 109.
[00044] The gap distance 144, i.e. the distance between rib 111 and rib 112
along
the face from which they protrude, is in the range of about 0.04 inches to
about 0.08
inches in an exemplary embodiment of the invention. This distance along with
the
lengths of ribs 111, 112 will allow rib 111 to deflect under rib 112 so that
rib 111 can
form a secure interface with container lip 109. Rib I1 I is preferably at an
angle of
between about 8 and about 12 , measured away from the vertical toward the lid
center
(see location 148 on FIG. 11). Flap seal height 150 as measured vertically
(shown in
FIG. 11) is preferably in the range of about 0.20 inches and about 0.30
inches.
[00045] In an illustrative embodiment of the invention, the thickness of flap
seal
111 ranges from a top thickness in the range of about 0.05 inches to about
0.07 inches; to
a bottom thickness of about 0.020 inches to about 0.03 inches (see 152 and
154,
respectively in FIG. 11). The composition of the flap material can affect
ideal thickness,
as both thickness and material composition affect stiffness, and hence sealing
capacity.
The proper thickness is that which maintains a suitable spring force of flap
111 against
the container.
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[00046] The distance 156, as shown on FIG. 11, from the face from which ribs
111, 112 protrude, to the top of rib 134 is preferably in the range of about
0.35 inches to
about 0.45 inches.
[00047] The distance 158, from the apex of container lip 109 to the lowest
point of
the lip 109, is preferably in the range of about 0.20 inches to about 0.30
inches.
[00048] The relative sizes of the seals stop (112) height and the flap seal
(111)
height are also important in order to form an adequate seal. In an exemplary
embodiment
of the invention, the seal stop height 146 is about 60% to about 80% of the
flap seal
height. In an illustrative embodiment of the invention it is in the range of
about .01 inches
to about .15 inches.
[00049] FIG. 12 depicts the container and lid of FIGS. 1-5 and shows various
measurements. For a container of that design having a volume of about 3.5
gallons to
about 7 gallons with a lid having an outer diameter in the range of about 11
inches to
about 13 inches, the various dimensions described above would also apply. In
addition
the height between the container lip apex and the lowest point of top most
satellite ring 3
should be optimized. This height is indicated in FIG. 12 by reference number
24. In an
illustrative embodiment of the invention, distance 24 is in the range of about
1.00 inches
to about 1.40 inches.
[00050] Dimension 26 as shown on FIG. 12, is also significant if a design such
as
that depicted in FIGS. I and 5 is used wherein the lid engages a satellite
ring in the pail.
Distance 26, which extends from the lid face from which ribs 111, 112 protrude
to the top
of hook 19, should be sized for adequate seal compression.
[00051] Embodiments of the invention also include a container and lid
assembly.
The lid and the container can be of any embodiment described herein, provided
that the
lid is compatible with the container to create the desired seals. FIGS. 1-7
depict circular
lids and pails, however, the scope of the invention includes other shaped
pails, such as
square and rectangular, for example.
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[00052] Embodiments of the invention include containers and lids comprised of
any material that can comprise the features that effectuate the seals
incorporated therein.
Generally, the lid features will need some flexibility to allow the ribs to
deflect toward
the pail to form a seal. The pail material does not necessarily need to be
flexible to form
the desired seals.
[00053] While the invention has been described by illustrative embodiments,
additional advantages and modifications will occur to those skilled in the
art. Therefore,
the invention in its broader aspects is not limited to specific details shown
and described
herein. Modifications, for example, to the specific container and lid shapes
and
materials, may be made without departing from the spirit and scope of the
invention.
Accordingly, it is intended that the invention not be limited to the specific
illustrative
embodiments, but be interpreted within the full spirit and scope of the
appended claims
and their equivalents.
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