CONTAINER LID

COUVERCLE DE RECIPIENT

English Abstract

Thermoformed plastic container lid comprising a substantially sheet like lid
body having a depending skirt (1) extending around the full periphery of the
lid body, the skirt (1) being suitable for engagement with the peripheral
portion of a plastic open top container, comprising a lid rim (2) in a
position near the periphery of the lid body, which divides the lid body in a
centrally located mirror (3) and an outer part (4) on the other side of the
lid rim (2), wherein the lid rim (2) comprises one or more bridges (5)
connecting the mirror (3) and the outer part (4).

French Abstract

L'invention concerne un couvercle de récipient en plastique thermoformable comprenant un corps sensiblement en feuille possédant une jupe dépendante (1) sur tout le pourtour du corps du couvercle, laquelle jupe (1) est conçue pour entrer en contact avec la partie périphérique d'un récipient ouvert en plastique. Ce couvercle de récipient comprend également un bord (2) situé dans à proximité du pourtour du corps du couvercle et divisant le corps du couvercle en un miroir central (3) et une partie extérieure (4) sur l'autre côté du bord du couvercle (2), le bord du couvercle (2) comprenant un ou plusieurs ponts (5) reliant le miroir (3) et la partie extérieure (4).

Claims

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Claims
1. Thermoformed plastic container lid comprising a
substantially sheet like lid body having a depending
skirt (1) extending around the full periphery of the
lid body, the skirt (1) being suitable for engagement
with the peripheral portion of a plastic open top
container, comprising a lid rim (2) in a position near
the periphery of the lid body, which divides the lid
body in a centrally located mirror (3) and an outer
part (4) on the other side of the lid rim (2),
characterised in that the lid rim (2) comprises one or
more bridges (5) connecting the mirror (3) and the
outer part (4).
2. Container lid according to claim 1, wherein the one or
more bridges (5) are in the same plane as the mirror
(3).
3. Container lid according to claim 1 or 2, wherein the
bridge is a partial bridge consisting of two bridge
parts (9,10), each being an indentation of a side wall
of the lid rim (2).
4. Container lid according to claim 3, wherein the
indentation is formed by placing part of the side wall
at a negative angle, compared to the side wall at a
place where there is no bridge.
5. Container lid according any of claims 1-4, comprising
four or more bridges (5).

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6. Container lid according to claim 5, comprising six or
more bridges (5) .
7. Container lid according to any of claims 1-6, wherein
the bridges (5) are distributed evenly around the
periphery of the lid.
8. Container lid according to any of claims 1-7,
comprising an uneven number of bridges (5).
9. Container lid according to any of claims 1-8, wherein
the width of the bridges (5) is 3 mm or more.

Description

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Container lid
Description
Field of the invention
The invention relates to a thermoformed plastic
container lid comprising a substantially sheet like lid
body having a depending skirt (1) extending around the
full periphery of the lid body, the skirt (1) being
suitable for engagement with the peripheral portion of a
plastic open top container, comprising a lid rim (2) in
a position near the periphery of the lid body, which.
divides the lid body in a centrally located mirror (3)
and an outer part (4) on the other side of the lid rim
(2). Such a container lid is also known as a two-step
container lid (see figure 1), as opposed to a one-step
container lid (see figure 2), in which the rim (2')
engages with the container rim.
Background to the invention
A two-step container lid as described in the preamble of
claim 1 is known from DE29910076U1. A two-step container
lid may be used in situations where the container is
covered with a cover foil, whereas the one-step lid may
not. The reason is that the mirror of the two-step lid
is at the same level as the top rim of the container and
the foil. A one-step container lid cannot be used in
combination with a foil at the level of the container
rim, since the mirror of the one-step lid will be at a
level below the level of the foil.

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A disadvantage of the known two-step container is that,
after initial opening, when the user wants to re-close
the container, the top rim of the container may fall
into the recess (8) of the lid rim (2), after which the
container cannot be closed. This re-closing problem
especially occurs, when the user wants to re-close the
container using one hand, and presses the lid on the
container from one side to the other.
It is therefore an object of the invention to avoid the
above re-closing problem.
Statement of the invention
This object is attained according to the invention in
that the lid rim (2) comprises one or more bridges (5)
connecting the mirror (3) and the outer part (4).
The bridge or bridges (5) will cause the lid to slide
over the container rim until the container rim is Caught
by the skirt (1), it is no longer possible that the
container rim enters into the recess (8) of the lid rim
(2) .
An additional advantage of the invention is that the
bridges (5) reduce or even avoid the problem of nesting
of the lids when stacked and put under pressure, e.g. in
a production line. Conventional two-step lids, may when
stacked and put under pressure nest, because the lid rim
(6) of a lower lid may be pushed into the recess (8) of
the lid rim (2) of a lid higher in the stack. This

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problem is also solved by the provision of bridges (5).
The tendency to nest is herein determined by measuring
the pressure needed to compress a stack of lids, and the
pressure needed is herein called the stack compression
resistance (expressed in N/m2).
Detailed description of the invention
The container and lid according to the invention may be
made by the technologies known in the art, from
materials known in the art.
The lid is made by thermoforming. In thermoforming a
plastic sheet softened by heat is formed either into or
around a mould. This forming step may be supported by
vacuum, air pressure, and material distribution may be
improved by plug assistance. There are three main groups
of thermoforming: vacuum forming, pressure forming and
matched mould forming.
The material of the lid and container may be any
material known for this use. Examples of possible
materials are HDPE (high density polyethyl.ene), LDPE
(Low density polyethylene), PP (polypropylene),
PET(Polyester Terephtalate), PVC (Polyvinylchloride),
OPVC (oriented PVC) , PC (Polycarbonate), EVOH
(Ethylenevinylalcohol) and multilayer materials of two
or more of these polymers.
The shape of the container lid may be any shape, for
example round, rounded rectangular, oval or square.

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The skirt (1) is preferably provided with indent
features (7) see figure 4. These indent features (7) fix
the lid on the container when closed.
In a preferred embodiment, the one or more bridges (5)
are in the same plane as the mirror (3). In another
preferred embodiment the lid rim (2) comprises four or
more bridges (5). Four bridges (5) may already be
effective if positioned on each of the sides of a square
or rectangular container lid. Preferably the container
lid comprising six or more bridges (5) and preferably
the bridges (5) are distributed evenly around the
periphery of the lid.
.Another preferred embodiment of the invention is shown
in figure 5, which shows the cross-section of the two
preferred lids at the place of a bridge. In this
preferred embodiment, the bridge is a partial bridge
consisting of two bridge parts (9,10), each bridge part
(9,10) being an indentation of a side wall of the lid
rim (2). Preferably, the indentation is formed by
placing part of the side wall at a negative angle,
compared to the side wall at a place where there is no
bridge, as shown in figure 5. The advantage of this
construction is that it is no longer possible that the
container rim enters into the recess (8) of the lid rim
(2) and that the stack compression resistance
is very high, because a load on the stack is effectively
transferred to lower lids, through the bridge parts
(9, 10) .

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The number of bridges may be easily determined by the
skilled person taking into consideration the size and
shape of the container lid. A large container lid will
need more bridges than a small container lid.
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In another preferred embodiment the container lid
comprises an uneven number of bridges (5) evenly
distributed around the periphery of the lid. This
improves the flexing strength of the lid, compared to
the same lid with an even number of bridges distributed
evenly around the periphery of the lid. Preferably the
width of the bridges (5) is 3 mm or more. The width
should be such that the bridge does not break when a
pressure commonly used to close the container is
applied. The features of the preferred embodiments
described above may be applied as such or in combination
with eachother.
The lid and container may be used for packaging consumer
goods, such as for instance foods, such as for instance
margarines or spreads.
Description of the drawings
Figure l: Cross-section of detail of two stacked one-
step container lids
Figure 2: Cross-section of detail of two stacked two-
step container lids
Figure 3: Top view of container lid according to the
invention having eight bridges

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Figure 4: Side view of conventional container lid
showing skirt ( 1 ) and indent features ( 7 ) ,
as may also be applied on the lid according
to the invention
Figure 5: Cross-section of detail of a preferred
embodiment, showing partial bridges (9,10)

Representative Drawing