Note: Descriptions are shown in the official language in which they were submitted.
FIELD OF THE INVENTION:
This invention relates to a lid Eor containers, and in
particular lids for beverage containers. The lid of the
present invention may be applicable for use with containPrs
designed for holding hot beverages or cold beverages, but is
more particularly intended for use wi~h cold beverages. rhe
lid of the presen~ invention is in~ended to be formed using
vacuum thermoforming process, from thin, flexible plastic sheet
material, usually polystyrene.
BACKGROUND OF THE I~VENTION:
Disposable lids for containers such as beverage cups, food
cups, and the like, are well known. Usually, when such lids
are disposable, they are made from an inexpensive thin,
flexible plastic material, such as polystyrene; which, however
does n~t have a significant amount of elasticity. Therefore,
in order to be able to be placed over and removed from the bead
of a container, the lids must be designed ~n such a manner that
they have a so-called "garter-spring" configuration. This
20 configuration compr~ses a plurality of convolutions or
corrugations, or other protruberances, formed on the skirt
portion of the lid.
By so configurlng cup lids and lids for food cups and the
like, such lids may be applied to and removed from the
container at least once, after which they are usually disposed
of. However, the llds must alfio first be stripped from the
27 mould on or in which they are made.
PAGE 1
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Certain difficul~ies have arisen from previous designs,
including difficulties in stripping the lids from moulds,
causing deformations or stress failure in the material of the
lids, or requiring special stripping st~tions which add to the
expense of lid production and which may slow down the process
of production.
Moreover, even though a lid may be designed to fit a cup
having a particular dimension, the manufacturing tolerances by
which such cups or other containers may be produced are such
10 that the diameter of the rim or mouth of the container, or the
size of the bead formed at the outer edge of the container, may
vary significantly~ so that lids designed to fit such
containers having a nominal size may not, in fact, do so. This
may result in a container wh~ch is much inclined to leakage
around the lid, and very often results in an inadvertent
stripping or dislodging of the lid from the container mouth,
partlcularly when more than one container, each having its own
lid, may be placed in a bag or other receptacle for carrying.
Still further, the space taken for shipping and storage of
20 prior art lids kas sometimes been quite significant. For
example, food vendors or the like may sometimes find that the
designated space that they have for lid storage, in which they
expect to store a specific number of lids as received from the
manufacturer, may not be quite enough space; or as a corollary,
either the producer of the lids or the food vendor may wish to
store more lids in a given amount of space. The present
27 invention provides a lower stacking height, so that each lid
occupies a somewhat smaller volume, which may be significant
PAGE 2
when storage of lids in amounts of thousands or even millions
or such lids is considered.
Certain prior paten~s are par~icularly indicative of the
kinds of lids in respec~ o which the present invention
provides an improvement; particularly as to ease of
stripability from moulds, lessening of the likelihood of
inadvertent removal from a container when placed thereon, and
accommodation of a wider tolerance of container siz s of a
nominal size.
Included among the prior art patents of interest is
ALDINGTON, United States Patent 2,922,563, issued January 26,
1960. That patent is specifically concerned wlth the provision
of a container closure which has a downwardly and outwardly
flared skirt which is then corrugated, and above and inwardly
of the skirt there ls located a cavity for fitting to the bead
of a container. ALDINGTON is also concerned with stackability,
by which lateral shifting of stacked lids relative to each
other is precluded. However, lids of the sort taught ~n
ALDINGTON are formed in female dies or moulds, and may be
20 easily dislodged from a container on which they are placed if
they are jostled agalnst other such lids on containers.
NEGORO, United States Patent 3,065,875, issued November
27, 1962, teaches a snap-on plastic cup lid having a
garter-spring flexibility in the skirt portion to permit
fitting to a cup bead, but which only accommodates and fits to
the cup bead discontinuously around the circumference thereof
27 by virtue of projections formed in the skirt portion.
Yet another approach is tàken by BREWER, United States
PAGE 3
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Patent 3,583,596, issued June 8, 1971 - reissued as Unlted
States Patent Re28,797, on May 4, 1976, with the same
disclosure. BREWER provides a lid having a conical skirt in
which is formed a plurality of spaced flutes, which vary in
dimension from top to bottom~ and whlch provide telescopic
rigidity to ~he skirt with sufficient conical strength to adapt
to the bead of the cup. BREWER is particuarly concerned with
nesting and s~acking, and provides three spaced stacking lugs
in the ~entral panel for that purpose.
A different approach, particularly to mounting the plastic
container closure on the container, is taken by BLAMCHARD,
United States Patent 4,026,459, issued May 31, 1977.
BLANCHARD provides a series of pro~ruberances around the
outside wall of the container, which thereby provides a
discontinuous bead to grip the rim of the cup or container.
Each of the protruberances may be disengaged from the rim of
the container, without causing displacement of adjacent
protruberances from engagement with the rim.
None of the above, nor any other known flexible plastic
20 lid for containers for food or beverages, whether hot or cold,
provides a lid which has a generally central panel and a
circumferentially extending cavity which opens downwardly and
inwardly to receive the bead of the container to which the lid
is to be fitted~ where the skirt portion which extends
downwardly from the cavity has a plurality of outwardly
p~o~ o~5
extending ~ r~ es~ , each of which has a substantially
27 vertical face and substantially vertical side edges and side
walls which extend inwardly from each face of each
PAGE 4
~rojection, and where ~he portions of the skirL between the
outwarclly extendino projec~ions, extend inwarclly to form a
discontinuecl waist which has an undercut clefinin~ the cavity in
the waist portions. Each of the outwardly extending
projections, and each of the discontinued waist portions
between them, all terminate at their lower portlons in a
downwardly and outwarclly slopecl lower bancl portion. the lower
band portion may, in turn, terminate at a su~stantially
vertically ciisposed downwardly extending wall portion, which
1~ may generally have an outwardly turned lip at its bottom. All
of the outwardly extending projections terminate at a
respective upper discontinued band portion which extends
inwardly and upwardly from the upper eclge of each of the
vertical faces of the projections, each of which terminales at
the cavity at an upper unclercut which is higher ancl less
inwardly extencling than the undercut of the waist portions, but
whicll also defines the cavity.
Thus, the present invention provides a thermoformed, thin
plastic lid for containers, generally formed of a plastic which
has no significant arnount of inherent elasticity, and which has
a continuous cavity formed at its upper periphery in such a
manner that the cavity can accommodate the beads of different
sized containers which have a given nominal size; i.e.~ the
bead-receiving cavity of lids of the present invention may
accornmoclate a wicle tolerance of bead size and mouth diameter of
containers for which any such ]id is nominally intendecl to be
27 used as a closure therefor.
Moreover, the present invention provides lids of the sort
PAGE 5
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spoken of above, which have a lower stacking height ~han prior
art lids, thereby permitting more lids to be stored in the same
spaceO
Still further, th~ presen~ invention provides lids which
may be formed on male moulds, a process which is somewhat less
expensive and more positi.ve as to the interior dimensions of
the lid -- which are the dimensions intended to be fitted to
the rim or mouth of a container __and yet the lids of the
present invention are easily stripped from the moulds on which
they are made.
Still further, the present invention provides lids which
are less likely to be disengaged from the container on which
they are fitted by jostling against similar lids on similar
containers.
BRIEF DESCRIPTION OF THE DRAWINGS:
~ ~ _ .
The above features and objects of the present invention
will become more evident, and are dis~ussed in greater detail
hereafter, together with o~her advantages of the present
20 invention, in association with the accompanyirlg drawings, in
which:
Figure 1 is a perspective view of a lid according to the
present invention fitted to a typical container;
Figure 2 is a partial plan view from above~ looking in the
direction of arrows 2-2 of Figure l;
Figure 3 is a partial cross-section of a lid, taken on
27 line 3-3 of Figure l;
Figure 4 is a partial cross-section similar to Figure 3 but
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taken on line 4-4 in Figure 1~ and,
Figure 5 is a partial cross-section showing a typical
stacking arrangement of lids according to the present
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS:
As noted, the present invention provides a lid 10, which
is intended for use with a container 12. The lid 10 is formed
of thin, flexible plastic material, usually polystyrene. If
the lid is made of polys~yrene plastlc material, tha~ material
is such that it does not generally have any significant amount
of elasticity, but is flexible. Indeed, the lid 10 of the
present invention is generally intended for manufacture using a
vacuum thermoforming process on male moulds 9 by which the
inside dimensions of the lid may be more particularly defined
and controlled. This is diseussed in greater detail hereafter.
The container 12 may generally be a paper container or
tub, intended for use with hot or cold beverages, milkshakes or
foodstuffs such as salads or the like. Usually, such
containers are formed of paper and may have a plastlc or wax
coating or lining, and have a bead formed on the outer edge of
their upper periphery or mouth3 such as the bead designa~ed 14
in Figures 3 and 4.
The lid 10 has a generally central panel 16, in which
there may be formed a vent or cross cut opening 18, through
which a drinking straw may be inserted.
p~Llr; p~ ,a ~1~
27 Specifically, the lid 10 has a ~trc~-~ere-~L~Iy extendi.ng
PAGE 7
cavity 2~ whicll is i~ol-me(l at the upl)er and outer extremity of
the lid, for receiving the bead 14 o~ the container 12 to which
the lid is to be fitted. The cavity 20 o~ens downwardly and
inwardly, in order to receive the bead 14.
~ leans such as an upwardly extendin~ circular rim 22 and an
inner skirt 24 may be provided, for connecting the cavity 20 to
the central panel 16; but the precise configuration is
immàterial to the present invention.
The outer portion of the lid 1~ comprises a skirt,
generally designated at 26, which extends downwardly ~rom the
cavity 20. Formed in the skirt 26 are a plurality of
outwardly extending projections 2$, each of which has a
substantially rectangular ~ront face, de~ined by verticaL side
eclges and inwardly extencling vertical side walls 30. Between
the outwardly extending projectio-ns 28 there are portions 32 oE
the skirt 26, which extend around the lid 10 in the skirt
portion 2G to form a discontinuecl waist indicated at 34. I`he
waist 34 ~orms an undercut which thereby defines the cavity 20
in the waist portions 32.
The outwardly extending projections 2~ and the
discontinued waist portions 32 all terminate at their lower
portion in a downwardly and outwardly sloped lower band portion
36. The lower band portion 36 may, in turn, terminate at a
substantially vertical, downwardly extending wall portion 3~;
which, in turn, may terminate at an outwardly extending lip 4~.
Each of the outwardly extending projections 28 terminates
27 at a discontinuecl band portion 42, which extends inwardly and
upwardly from the vertical outer face o~ each
PAGE 8
outwardly exterldiTlg projection 2~. ~ach barl(l portion 42
terminates at the cavity 2~ at an undercut 44, which is higher
and less inwardly extending than the undercut 34, and which
also defirles the cavity 2~ in each region of the skirt portion
26 over the outwardly extending projecti.ons 2~.
~ igure 3 is taken through a waist portion 32, so as to
indicate the relationship of the cavity 2~ and the undercu~ 34
to the bead 14 of a container 12. Like~ise, FigJure 4 is taken
through an outwarc31y extending projection 2$, to demonstrate
1~ the relationship of the undercut 44 to the bead 14 and
container 12.
Very eviclently, as a lid 10 is being placed over the bead
14 oE the container 12, it flexes in each undercut portion 34,
sufficiently that the li.d may be pushed downwardly over the
bead, so that it then accommodates the bead due to its
flexibility.
l~1hat is also evident, from the above discussion and with
reference particularly to Figures 3 and 4, is that a wide
tolerance of bead dimensions and of outer diameter dimensions,
2~ from extremities of the bead 14 of containers 12, may be
accommodated, due to the interaction o~ both of the undercuts
44 and 34 against the bead 14. Thus, a tight fit of the lid lU
to the bead 14 of the container 12 is assured, over a
relatively wide range of bead sizes and outer diameters.
~ loreover, because it is advantageous to form the lids of
the present invention on male molds, it is evident tha~ the
27 discontinuities of the undercuts 34 and 44 make it easier to
strip the lids from the
PAGE 9
moulds on which they are formed.
Figure 5 shows one possible rela~ionship of vertically
contiguous lids 10 in a stacking arrangement, where that
portion of the lid which deines the cavity 20 oE the bottom
lid extends up to and interferes with the underside of the
waist portions 32 of the upper lid. Obviously, there may be a
possibility that the upper and outer port:ion of the lower lid
10 may also extend up to and interfere with the upper band
portion 42 of the upper lid 10. Thus, in that event, the lids
10 would nest very closely one with another, if necessary.'
The configuration of the lids is such that, in any event,
when the lids are stacked and nest against each other, they do
not lock one on another.
However, even in a normal stacking position as lndieated
in Figure 5, it is clear that there is a minimal space taken
for each lid, because of the rela~ive nesting position in any
event of the lids one with respect to the next adjacent lid
above it.
Indeed, as an example, lids of a size intended to fit
20 containers having a nominal diameter of 3.75 inches may stack
such that one hundred llds occupies 15 inches of height, as
opposed to the 19 inches of height taken by ordinary lids of
the sort, for example, that are illustrated in the BREWER
patents referred to above. This represents a saving of 20% of
storage volume; and when storage and shipping of lids in
amounts of hundreds of thousands or millions is considered,
27 such saving is quite significant.
On a lid of the present invention, it is usual that the
PAGE 10
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circumterenti~ tl~ e.lcll of ~l~e outwar(lly extending
projections 2~ -- i.e., the widtll across the face of the
~rojections 2~ -- is approximately the same as the
circumferential leng~h of the waist portions 32 between them.
Such outwardly extending projections 2~ may be put into place
such that the distance between a point on one of them and the
respective point on the next adjacent outwardly extending
discontinuity (e.g., between the centre lines of each), is 1
degrees.
In general, the cross-section of the cavity, in the
portion thereof as i:Llustrated in each of Figures 3 and 4, is
transversely arcuate -- i.e., at least the extreme outer
portion of the material of the lid lU which defines the cavity
20 forms a segment of an arc. Generally, the position of the
upper undercut 44 is such as to be just below and inward of a
vertical tan~ent to the mate~rial clefinin~, the cav;ty 2(), at
that point.
Obviously, because of the sul~stantially straigh~ sides in
the skirt portions 26 of lids 10 according to the present
2~ invention, and the positive engagement of the unclercuts 34 and
44 to the bead 14, there is consicderably less likelihood of
interference between adjacent lids as they may be jostle~
against one another when bein~ carried in a bag or other
receptacle, so that the likelihood of one of the lids being
stripped from its respective container is lessened. Indeecl, it
is evident that, if the container is li~ted by radially
27 inwardly directed pressure between the thumb and fingers of the
hand, against the slcirt portions 26 or against the outer eclge
PAGE 11
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of the rim portions 40 thereof, additional pressure of the
undercuts 34 and 44 against the underside of the bead 14 of the
container 12 is created, thereby even more particularly
assuring a secure fit of the lid 10 to the container 12. That
same pressure may also exist as adjacent lids 10 may rub or
jostle against each other.
Also, because ~he bottom of the lower band portion 36 and
the vertical wall 38 of the skirt portion 26 of the lid 10
according to this invention is at a wider diameter than that of
the cavity 20, it is very easy to fit a lid 10 to a container.
This wider bottom opening of a lid 10 according to this
invention, is such ~hat substantially automatic placement of
lids 10 on containers may be accommodated, for example in
dispensing machines.
Moreover, as mentioned above, the depth of the undercuts
34 provides an accommodation of a variety of bead sizes and
bead diameters, for any speclflc nominal size ofcontainer 12.
For example, lids having a diameter such as to accommodate cups
having a nominal mouth diameter of 3.75 inches may have
20 undercuts of 0.025 inches at each side as opposed to an
undercut of 0.015 of the waist portion of lids such as those
referred to in the BREWER patents mentioned above, thereby
giving an additional 0.02 inches across the diameter of a cup
or container. Thus, a variation of up to about 1% of nominal
diameter of the mouth of the container 12, or indeed of the lid
10, may be accommodated. This is all the more important when
27 it is recognized that shrinkage of polystyrene film material of
the sort from which lids according to the present invention are
PAGE 12
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normally manufactured may be up to 0.004 inches per inch of
diameter of the lid, but variations of shrinkage are such ~hat
they may not be posi~ively forecast and designed for in the
manufac~ure of each die from which lids according to the
present invention may be made. This is especially true when it
is considered that the thickness of the polystyrene material,
which is extruded, may vary from time to time and from machine
to machine.
There has been described a lid for containers, which may
10 be used with food tubs or cups for hot or cold beverages, for
example, and which may normally be ormed of thin, flexible
plastic material such as polystyrene, using a vacuum
thermoforming process over male moulds. Certain specific
features of the lids according to the present invention have
been described and their advantagès explained. Other
variations, and specific design considerations particularly as
to the central panel portion, and as to the conformation of the
wall portlon 38 and rim 40 which may be eliminated, may be
provided for, without departing from the spirit and scope of
20 the appended claimsO
27
PAGE 13
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