U.S. patent application number 13/453351 was filed with the patent office on 2012-11-29 for plastic container structure.
Invention is credited to Arne Danielsson.
Application Number | 20120298669 13/453351 |
Document ID | / |
Family ID | 46044415 |
Filed Date | 2012-11-29 |
United States Patent
Application |
20120298669 |
Kind Code |
A1 |
Danielsson; Arne |
November 29, 2012 |
PLASTIC CONTAINER STRUCTURE
Abstract
The present invention relates to a plastic container structure
(1) comprising a lid (2), a gasket (3), and a container (4). The
lid (2) is configured to be attached to the container (4) to close
it by movement of the lid (2) relative to the container (4) along
an engagement direction (D). The container (4) has an opening
defined by a circumferential flange (5) having a circumferential
seat (6) for receiving the gasket (3). Also, the lid (2) has a
circumferential wall (7) configured to surround the circumferential
flange (5) of the container (4). The seat (6) is provided on the
outside of the flange (5) of the container (4) opposite the
circumferential wall (7) of the lid (2) and the seat (6) and the
circumferential wall (7) of the lid (2) are configured such that
the gasket (3) is compressed between the circumferential wall (7)
of the lid (2) and the seat (6) of the container (4). The
circumferential flange (5) of the container and/or the wall (7) of
the lid (2) are convex in a plane substantially perpendicular to
the engagement direction (D).
Inventors: |
Danielsson; Arne; (Hoor,
SE) |
Family ID: |
46044415 |
Appl. No.: |
13/453351 |
Filed: |
April 23, 2012 |
Current U.S.
Class: |
220/345.3 ;
220/345.6 |
Current CPC
Class: |
B65D 2543/00972
20130101; B65D 2543/00648 20130101; B65D 2543/00685 20130101; B65D
2543/00537 20130101; B65D 2543/00555 20130101; B65D 2543/00796
20130101; B65D 43/0212 20130101; B65D 2543/00101 20130101; B65D
2543/0074 20130101; B65D 2543/005 20130101; B65D 2543/00296
20130101 |
Class at
Publication: |
220/345.3 ;
220/345.6 |
International
Class: |
B65D 43/10 20060101
B65D043/10; B65D 53/02 20060101 B65D053/02; B65D 41/18 20060101
B65D041/18 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 21, 2011 |
SE |
1150357-0 |
Claims
1. A plastic container structure (1) comprising: a container, a
gasket, and a lid configured to be attached to said container to
close it by movement of the lid relative to the container along an
engagement direction, wherein the container has an opening defined
by a circumferential flange having a circumferential seat for
receiving the gasket, wherein the lid has a circumferential wall
configured to surround the circumferential flange of the container,
wherein the seat is provided on the outside of the flange of the
container opposite the circumferential wall of the lid, and wherein
the seat and the circumferential wall of the lid are configured
such that the gasket is compressed between the circumferential wall
of the lid and the seat of the container, wherein the
circumferential flange of the container and/or the wall of the lid
are convex in a plane substantially perpendicular to the engagement
direction.
2. The plastic container structure according to claim 1, wherein
the lid is further provided with support means, said support means
being configured to contact the flange of the container from the
inside of the container such that movement of the flange of the
container due to forces from compression of the gasket is
prevented.
3. The plastic container structure according to claim 2, wherein
said support means comprises a ridge extending at a distance from
and parallel to the circumferential wall of the lid.
4. The plastic container structure according to claim 2, wherein
the support means are convex in a plane substantially perpendicular
to the engagement direction.
5. The plastic container structure according to claim 1, wherein
the circumferential wall of the lid extends a distance past the
gasket substantially along said engagement direction, and wherein
an end portion of the circumferential wall of the lid is provided
with engagement means for interlocking engagement with
corresponding interlocking means of the container, said engagement
and interlocking means being configured to prevent the lid from
moving away from the container along the engagement direction.
6. The plastic container structure according to claim 5, wherein
said engagement means comprises a protrusion extending along the
circumferential wall of the lid on the inner side of the lid.
7. The plastic container structure according to claim 5, wherein
said interlocking means of the container comprises a flange
extending from the circumferential flange of the container
substantially along said engagement direction.
8. The plastic container structure according to claim 7, wherein
said flange of the interlocking means of the container is outwardly
slanted away from the circumferential flange of the container.
9. The plastic container structure according to claim 1, wherein
the gasket is an O-ring.
Description
TECHNICAL FIELD
[0001] The present invention relates to a waterproof plastic box
suitable for injection molding. More specifically, the present
invention relates to a joint design for a waterproof joint between
plastic parts, in particular a waterproof plastic box suitable for
containing electronics.
BACKGROUND
[0002] Plastic containers with removable lids are well known in the
art and may be used for storage and protection of for example
objects or cooked food. Plastic containers typically are not
airtight and hence are not suitable for protection of sensitive
electronic equipment. Another problem of known plastic containers
are that they have to be designed in such a way that they can be
injection molded. Therefore, a plastic container which may be
manufactured by injection molding and which is airtight would be
beneficial. A further problem is how to design a plastic container
that can be manufactured with an inexpensive mold with high
tolerances, little wear on the mold and with short injection and
cooling times for each molded container. Yet another problem is
that plastics typically creep over time, which leads to deformation
of the plastic parts and eventually leads to air leaks of the
container produced using said plastic parts.
SUMMARY
[0003] Hence, an object of the invention is to provide a plastic
container which is airtight, which can be manufactured by injection
molding in an inexpensive mold and which is not prone to leaking
over time.
[0004] These and other objects and advantages, which will be
obvious from the following description of the present invention,
are achieved by a plastic container structure according to the
independent claim.
[0005] According to an aspect of the invention a plastic container
structure is provided comprising a container, a gasket and a lid.
The lid is configured to be attached to the container to close it
by movement of the lid relative to the container along an
engagement direction. The container has an opening defined by a
circumferential flange having a circumferential seat for receiving
the gasket. Also, the lid has a circumferential wall configured to
surround the circumferential flange of the container. The seat is
provided on the outside of the flange of the container opposite the
circumferential wall of the lid and the seat and the
circumferential wall of the lid are configured such that the gasket
is compressed between the circumferential wall of the lid and the
seat of the container. The circumferential flange of the container
and/or the wall of the lid are convex in a plane substantially
perpendicular to the engagement direction
[0006] An advantage of the plastic container structure is that the
gasket is compressed inwards by the circumferential wall of the
lid, which in turn leads to the gasket being compressed in a
direction substantially different from the direction in which the
lid is moved onto the container. This results in that the gasket
will not act to force the lid off the container, since the
compressed gasket does not act to push the lid back off the
container, but rather to try to expand the circumferential measure
of the circumferential wall of the lid. Here, a further advantage
is that the circumferential wall distributes forces from the
compressed gasket over a large area along the gasket, thus reducing
stress in the material of the wall of the lid, which in turn
prevents creep and deformation of the lid. Altogether, this enables
airtight sealing along and between the container and the lid. The
design of the container structure makes it possible to manufacture
the structure in inexpensive molds without sliders. Also, the
convexity brings an advantage in that the flange of the container
and the circumferential wall surrounding the flange are both made
more stable against deformation due to compression forces from the
gasket acting on the flange and the wall. Especially, it should be
noted that the wall portion immediately surrounding the gasket
forms a convex ring surrounding the gasket, which ring receives and
distributes stress from forces from the gasket such that material
creep in other parts of the lid is prevented. The convex shape
results in that any movement of the wall outwards requires
circumferential extension of the circumferential wall. If one or
more wall portions would have been straight, the wall would
initially be able to move slightly outwards without tensioning the
wall but rather tensioning the material connecting the wall portion
and the rest of the lid. The same physical rules and reasoning
applies for the circumferential flange of the container for which
any movement inwards will cause compressive forces in the flange,
due to its convex shape.
[0007] According to an embodiment, the lid is further provided with
support means, said support means being configured to contact the
flange of the container from the inside of the container such that
movement of the flange of the container due to forces from
compression of the gasket is prevented. This brings an advantage in
that the circumferential flange of the container will be stabilized
such that material stress will be reduced in other parts of the
container, effectively preventing unnecessary stress and creep of
the container.
[0008] The support means may comprise a ridge extending at a
distance from and parallel to the circumferential wall of the lid.
This brings an advantage in that it provides support along the full
length of the circumferential flange of the container whilst at the
same time being easy to manufacture in a mold without the
complexity of extra slides or cores.
[0009] The support means of the lid may be convex in a plane
substantially perpendicular to the engagement direction. The
convexity brings an advantage in that the support means is made
more stable against deformation due to compression forces from the
gasket acting on the flange.
[0010] According to an embodiment, the circumferential wall of the
lid extends a distance past the gasket substantially along said
engagement direction. Also, an end portion of the circumferential
wall of the lid is provided with engagement means for interlocking
engagement with corresponding interlocking means of the container.
The engagement and the interlocking means are configured to prevent
the lid from moving away from the container along the engagement
direction. This brings an advantage in that the lid will be firmly
secured to the container independently of the gasket seal.
[0011] The engagement means may comprise a protrusion extending
along the circumferential wall of the lid on the inner side of the
lid. This brings an advantage in that the interlocking engagement
is provided for around the whole circumference of the lid. A
further advantage is that the protrusion is easily provided for in
the mold without any need for extra slides or cores, since the lid
design allows the wall of the lid to spring outwards during
extraction/release from the associated mold core, such that the
protrusion slides out of its cavity in the mold core where after
the lid may be ejected/released from the mold core.
[0012] Further, the interlocking means of the container may
comprise a flange extending from the circumferential flange of the
container substantially along said engagement direction. This
brings an advantage in that the interlocking means provides a
locking surface all around the circumference of the container, such
that the engagement means of the lid may grip the container around
the whole circumference of the container.
[0013] Also, the flange of the interlocking means of the container
may be outwardly slanted away from the circumferential flange of
the container. This brings a further advantage in that the flange
is suitable to injection molding, since no extra slides or cores
are needed to shape the outwardly slanted flange. Further, the
outside surface of the flange provides a slanted surface along
which the engagement means of the lid slides during engagement of
the lid to the container, which in turn promotes relaxation of the
gasket during engagement/disengagement of the lid, since the
circumferential wall of the lid is moved outwards.
[0014] The gasket may be an O-ring. This brings an advantage in
that 0-rings have a continuous cross section, thus require less
attention when mounting on the container. Further, O-rings are
inexpensive and are readily available, which in turn provides for
easy future service and replacement.
BRIEF DESCRIPTION OF DRAWINGS
[0015] Embodiments of the present invention will in the following
be described with reference to the appended drawings, in which:
[0016] FIG. 1 shows an exploded view of a container structure
according to an embodiment of the invention;
[0017] FIG. 2a-c shows a front view, a top view, and a side view of
the container structure also shown in FIG. 1;
[0018] FIG. 3 shows an exploded cross-sectional view of
cross-section B-B of the container structure also shown in FIGS. 1
and 2a-c;
[0019] FIG. 4 shows a non-exploded cross-sectional view of
cross-section B-B of the container structure also shown in FIGS. 1
and 2a-c; and
[0020] FIG. 5 shows an enlarged portion of the cross-section of
FIG. 4 without cross-hatching for improved clarity.
DETAILED DESCRIPTION
[0021] As shown in FIGS. 1-5, a plastic container structure 1
according to an embodiment of the invention comprises a lid 2, a
gasket 3, and a container 4. The lid 2 is configured to be attached
to the container 4 to close it by movement of the lid 2 relative to
the container 4 along an engagement direction D. The container 4
has an opening defined by a circumferential flange 5 having a
circumferential seat 6 for receiving the gasket 3. Also, the lid 2
has a circumferential wall 7 configured to surround the
circumferential flange 5 of the container 4. The seat 6 is provided
on the outside of the flange 5 of the container 4 opposite the
circumferential wall 7 of the lid 2 and the seat 6 and the
circumferential wall 7 of the lid 2 are configured such that the
gasket 3 is compressed between the circumferential wall 7 of the
lid 2 and the seat 6 of the container 4.
[0022] The plastic material of choice of the container 4 and the
lid 2 is a thermoplastic material suitable for injection molding.
Particularly suitable materials are PMMA, PA, CA, PETG, and PC.
[0023] Suitable materials for the gasket 3 are elastomers commonly
used for making gaskets, such as rubber, PU, TPE, and silicon
rubber. In the embodiment shown in FIGS. 1-5, the gasket 3 is an
O-ring, but it could as well have other forms and it may also be
molded directly onto the container 4.
[0024] When assembling and closing the container structure 1, the
gasket 3 is first placed around the container 4 in the seat 6
provided on the outside of the flange 5 of the container 4.
Thereafter, the lid 2 is aligned with the container 4 and pushed
onto the container 4, e.g. by pressing. The box assembly is not
easily openable due to the specific configuration of container and
lid which is discussed further below. Hence, the closed box is
secure and reliable as regards remaining closed and airtight.
Depending on the specific design of the lid 2 and the container 4,
the direction of engagement D in which the lid 2 has to be moved
relative to the container 4 may vary. For example, the direction of
engagement D may be perpendicular to the top surface of the lid 2
and the surface of the bottom of the container, i.e. the direction
of engagement D essentially coincides with the direction of the
flange 5. The gasket 3 is compressed between the circumferential
wall 7 of the lid 2 and the seat 6 of the flange 5 of the container
4. This results in that the gasket 3 will not act to force the lid
2 off the container 4, since the compressed gasket 3 does not act
to push the lid 2 back off the container 4, but rather to try to
expand the circumferential measure of the circumferential wall 7 of
the lid 2. Hence, once the lid 2 is engaged with the container 4 to
close and seal the container 4, there is little to no built in
stress acting to move the lid 2 off the container 4.
[0025] According to an embodiment, the lid 2 is further provided
with support means 8, said support means 8 being configured to
contact the flange 5 of the container from the inside of the
container 4 such that movement of the flange 5 of the container 4
due to forces from compression of the gasket 3 is prevented. This
brings an advantage in that the circumferential flange 5 of the
container 4 will be stabilized such that material stress will be
reduced in the container 4, effectively preventing unnecessary
stress and creep of the container 4. Hence, the gasket 3 is mainly
compressed by forces from the support means 8 and the
circumferential wall 7 of the container 4.
[0026] According to an embodiment, as shown in FIGS. 1-5, the
support means 8 comprises a ridge extending at a distance from and
parallel to the circumferential wall 7 of the lid 2.
[0027] This brings an advantage in that the support means 8
provides support along the full length of the circumferential
flange 5 of the container 4 whilst at the same time being easy to
manufacture in a mold without the complexity of extra slides or
cores.
[0028] According to an embodiment, the circumferential flange 5 of
the container 4 is convex, which is to be construed as that the
flange 5 is outwardly convex in a plane substantially perpendicular
to the engagement direction D, as shown in FIG. 2b. The flange 5
may have a convex shape wholly or in part. The wall 7 of the lid 2
may also be convex, i.e. the wall 7 is outwardly convex in a plane
substantially perpendicular to the engagement direction D.
"Outwardly convex" is to be construed as the flange 5 and/or the
wall 7 having a convex shape as seen from the outside of the box,
i.e. that the flange 5 and/or wall 7 bends outwards in a direction
from the centre of the box/container/lid. "In a plane" means that
the flange 5 or wall 7 may be convex in two directions, i.e. in
both directions contained within that plane. This brings an
advantage in that the flange 5 of the container 4 and the
circumferential wall 7 surrounding the flange 5 are both made more
stable against deformation due to compression forces from the
gasket 3 acting on the flange 5 and the wall 7 respectively.
Especially, it should be noted that the portion of the wall 7
immediately surrounding the gasket 3 forms a convex ring of
material surrounding the gasket 3, which ring of material receives
and distributes stress caused by forces from the gasket 3 such that
material creep in other parts of the lid 2 is prevented. The convex
shape results in that any movement of the wall 7 outwards requires
circumferential extension of the wall 7, effectively providing good
compression of the gasket 3 along the whole length of the gasket 3
and not only in corners of the container structure 1. If one or
more wall portions would have been straight, those wall portions
would initially be able to move slightly outwards without
tensioning the wall 7 but rather tensioning material connecting the
wall 7 to the rest of the lid 2.
[0029] The same reasoning applies for the circumferential flange 5
of the container 4 for which any movement inwards will cause
compressive forces in the flange 5, due to its convex shape.
[0030] Also, the same reasoning regarding convexity holds for the
support means 8 according to the embodiment shown in FIGS. 1-5
comprising a ridge extending at a distance from and parallel to the
circumferential wall 7 of the lid 2. The support means 8 may have a
convex shape wholly or in part, i.e. the support means 8 is
outwardly convex in a plane substantially perpendicular to the
engagement direction D. "Outwardly convex" is to be construed as
the support means 8 having a convex shape as seen from the outside
of the box, i.e. that the support means 8 bends outwards in a
direction from the centre of the lid. "In a plane" means that the
support means 8 may be convex in two directions, i.e. in both
directions contained within that plane.
[0031] According to an embodiment, the circumferential wall 7 of
the lid 2 extends a distance past the gasket 3 substantially along
said engagement direction D. Also, an end portion of the
circumferential wall 7 of the lid is provided with engagement means
9 for interlocking engagement with corresponding interlocking means
10 of the container 4. The engagement 9 and the interlocking means
10 are configured to prevent the lid 2 from moving away from the
container 4 along the engagement direction D.
[0032] This brings an advantage in that the lid 2 will be firmly
secured to the container 4 and that deformation of the engagement
means 9 and the interlocking means 10 will not substantially affect
the sealing function of the gasket 3. Since the wall 7 extends
substantially along said engagement direction, a compact container
structure 1 is achieved. Further, moldability is maintained.
[0033] According to an embodiment, the engagement means 9 comprises
a protrusion extending along the circumferential wall 7 of the lid
2 on the inner side of the lid 2. The protrusion extends inwardly
in a plane substantially perpendicular to the engagement direction
D. "Inwardly" is to be construed as the protrusion extending
inwards as seen from the outside of the box, i.e. that the
protrusion extends inwards in a direction towards the centre of the
box/container/lid.
[0034] The interlocking means 10 comprises a flange extending from
the circumferential flange 5 of the container 4 substantially along
the engagement direction D. This is to be construed as said second
type of flange being a kind of extension of the first flange 5 in
said direction. Further, the flange of the interlocking means 10 of
the container 4 is outwardly slanted away from the circumferential
flange 5 of the container 4.
[0035] Further, the locking engagement may be accomplished by other
methods such as gluing, welding, screwing, bolting, riveting, and
shrinking, in addition to the above discussed use of a protrusion
and/or flange.
[0036] The invention has been described above with reference to
some embodiments. However, it is obvious to the person skilled in
the art that additional embodiments are possible within the scope
of the invention.
* * * * *