Note: Descriptions are shown in the official language in which they were submitted.
CA 02406653 2002-10-25
-1-
Applicant: SULO Eisenwerk Streuber & Lohmann GmbH
Our File: 53357 AI/Gr
Container comprising a body and a cover
1. Field of Application
1 o The invention relates to a container comprising a barrel-like body and a
fitting,
tight cover.
II. Technical Background
It is common practice today to fill the pulverulent homopolymers and
copolymers
of tetrafluoro ethylene (TFE) into barrel-like plastic containers or fiber
drums which
preferably have a cup-shaped body and a cover fitting thereon. The containers
serve to protect the mentioned polymers, which are often produced and
processed
2 o under clean-room conditions, against dust and humidity as well as
compressive
stress. In the processing of TFE-polymerisates foreign substances of any kind,
humidity and polymer particles that are compressed due to the exertion of
compressive stress lead to defects in the moulded parts or extrudates produced
from the polymerisates, which are unacceptable particularly in the case of
thin
walled products such as wire coatings or films.
For high-quality end applications plastic containers made of polypropylene for
example are preferred to fibre drums for the packing of polytetrafluoro
ethylene
(PTFE) powders as the plastic containers possess an improved surface quality
3 o and dispense with the insertion of a film inliner as a protection for the
powders.
The plastic containers have to meet high demands of various kinds: They have
to
be sufficiently tight even when being opened and closed repeatedly. Moreover,
according to DE-U-94 08 630 they have to withstand the compressive stress
caused by the stacking of the filled containers onto the individual packing
units. In
practice two to four pallet bundles are stacked, which are each loaded with
two to
three container layers. The containers are filled with 20 to 50 kg of powder.
During
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_2-
the filling specific charging levels must not be exceeded in the container
since a
baking of the powder might otherwise occur, as a result of which a correct
processing is not guaranteed.
In their technically complicated high-quality constructions containers for
PTFE-
powder are preferably produced by means of injection moulding. In this process
standard plastics such as polypropylene or polyethylene are employed for cost
reasons. Since the containers are required to have a high stability during
transport
and storage even at temperatures ranging between -20°C and 60°C,
chemically
1 o modified propylene copolymers are preferably used as material. The packing
systems are of great value so that the aim is their reuse by, for instance,
cleaning
and re-filling.
The demands made on the sealing of the containers for PTFE powder are of a
very specific kind. Compared to the known single-cover system as for example
for
coatings the packing system according to EP-B-362 959 is a round three
component system consisting of container body, cover and tensioning ring. The
sealing principle resides in the fact that the upper part of the body runs out
to the
outside in a declining manner, while thin by-pass lugs located in the internal
edge
2 0 of the cover are pressed onto the upper part of the body by means of the
tensioning ring. However, the restoring force of these by-pass lugs is small
so that
the ,degree of sealing is greatly reduced after the first opening and closing.
A
reusage of the cover and a recycling of the container is practically
impossible.
Furthermore, the production of the tightening thin sealing lips by means of
the
injection moulding method involves great expense from a technical point of
view
and is susceptible to failure as the complete injection moulding of the thin
sealing
lips requires a complicated venting in the injection moulding tool. In the
injection
moulding process polymeric depositions may for example cause a complete or
3 o partial blocking of the venting areas which leads to an incomplete
injection
moulding of the thin by-pass lugs so that the sealing function is no longer
ensured.
This kind of sealing by means of thin by-pass lugs in the inside of the cover
is
described analogously in WO-A-96/37 410 for a rectangular plastic container.
According to US-A-4 674 650 a sealing is described for a round plastic
container,
which consists of container body, cover and tensioning ring. The sealing is
CA 02406653 2002-10-25
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effected by a sealing ring that is additionally inserted in the cover and
seals the
external downward directed body_ The insertion of an additional sealing ring
of a
resilient material bears various disadvantages: It renders the system more
expensive, makes the automatic cleaning of the packing system prior to its use
s more difficult and when the system is being disposed of it has to be
separated as
an additional material component if the material of the container is to be
used in a
recycling method.
In a packing system customary in the trade which consists of container body,
1 o cover and tensioning ring of the company Sulo Plast GmbH 8 Co. KG the
sealing
is effected by moulding an elastomeric seal, for example of polyurethane, into
a
groove located in the cover. This elastomeric seal tightens against the upper
edge
of the body. The fundamental disadvantage of this system is that the seal can
be
damaged under the compressive stress exerted on the elastomeric seal during
15 transport and storage. Parts of the seal are detached and can penetrate the
PTFE-powder to be protected. Moreover, in this case too the elastomeric
component has to be separated if the container covers are used in a recycling
method after the packing system has been used.
2 o Furthermore, EP A-4 269 032 describes a snap-in device to attach a cover
to a
container, on which a rim 10 is formed on the upper edge of the container and
a
sealing surface is formed on the edge of the cover for mutual engagement. In
addition, further grooves and webs are designed on container and cover, which
may also have a sealing effect, as described in column 4, line 2'T_
However, the snap-in elements that serve to attach the cover are not part of
the
aforementioned sealings.
Likewise an encircling flange with snap-in straps that are formed separately
and
3o embrace the edge cannot be taken from D1.
A~~/I~E IV DE U
SHEcT
CA 02406653 2002-10-25
-3a-
Ill. Representation of ~e Invention
a) Technical Problem
The object of the present invention is to provide a container with a seal
which
prevents contamination of the contents during transport and storage, permits
repeated opening and closing without reducing the degree of sealing and
dispenses with the use of an elastomeric seal as an additional material
component whilst consisting of the smallest possible number of individual
1 o components.
b) Solution of the problem
This problem is solved by the characterizing features of claim 1. Advantageous
embodiments become apparent from the subclaims.
Since the first sealing point 4 is axially spaced from the tensioning device 3
the
intem~ediate cover and/or body can be constructed in such an manner that they
are resiliently deformable between the released and tensioned state while the
zo resilient restoring force ensures tightness. In addition, due to the
spacing in the
portion of the tensioning device a second sealing point 5 can be arranged so
that
altogether a very high safety of the sealing is provided.
AMENDED
SHEET
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On account of the cup-shaped container open to one side and the cover that
fits
thereon the sealing points are always designed such that they are closed over
the
circumference, regardless of whether the basic form of the container is round
or
polygonal.
to
The tensioning device is preferably designed integrally with one of the
container
parts, preferably it is integral with the cover and preferably not in a
continuous
fashion over the circumference but provided at a plurality of separate points,
for
instance at four points that are each distributed by approximately 90°.
In this the tensioning device consists of a radially downward extending snap-
in
projection, which is preferably formed on the body and consists by preference
of
an annular flange that is continuous over the circumference, and of a snap-in
recess that is radially open to the inside and formed on the snap-in straps of
the
2 o cover to accommodate the annular flange as snap-in projection.
The snap-in straps have a considerably smaller wall thickness in the portion
of the
snap-in recesses, i.e. the bottom of the snap-in recess, than laterally beside
the
snap-in straps. Since the radially protruding cover edge that leads towards
the
2 5 snap-in recess also has a relatively high material thickness, which
preferably still
increases radially from the outside to the inside, the snap-in straps 33, when
being
radially deformed to the outside to open the tensioning device, can be
deformed
preferably in the portion having a small material thickness, i.e. in the
portion of the
groove bottom of the snap-in recess, or the encircling cover edge can be
3 o deformed in its entirety in the connecting portion axially above the snap-
in recess
32.
Furthermore, in the following the first sealing point is described in such a
manner
that the sealing surface (groove) is formed in the cover and the sealing web
3 5 (upper edge of the wall of the body) is formed on the container, whereas
this
allocation is exactly the other way round in the second sealing point
(flange).
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In one sealing point or also in both of them the allocation of sealing surface
and
sealing web to the body or cover may also be the other way round in each case,
hence for example the free upper end of the edge of the body may have V-shaped
grooves, into which a fitting projection of the cover might engage.
On account of the high sealing probability of each sealing point and
consequently
the high sealing safety of the container as a result of a plurality of
separate sealing
points and their movability to each other the risk can be run that body and
cover
directly rest against each other at the sealing points, i.e. without inserting
a
1 o specific, more resilient sealing material, which has the advantage of
being easier
to recycle and makes for a reduced risk of contamination of the contents by
detaching parts of the sealing material.
Through a sufficient axial spacing of the sealing points the distance can be
used
for the adjustment of diameter and/or length and thus the sealing probability
can
be increased at both sealing points. If at least one of the sealing points is
in
addition divided into a plurality of partial sealing points, the sealing
probability is
increased further through this even if e.g. the sealing webs of the partial
sealing
points are not or are scarcely movable with respect to each other.
The following descriptions always relate to the cross sectional forms of the
respective parts of cover or body only. With the exception of the snap-in
straps
these points are always shaped in an annularly encircling manner in accordance
with the annularly encircling shape of the body, which is round or polygonal
or
2 5 freely formed, i.e. the circumferential walls of the body as seen in top
view.
In a preferred embodiment the first sealing point consists of the free upper
end of
the edge of the body as sealing web, onto which a groove formed in the
underside
of the cover is seated that preferably has a V-shaped cross section. The
diameter
3 0 of the upper end of the edge of the body is slightly larger than the
diameter of the
groove in the cover so that due to the axial pressing-on of the cover the
flank of
the groove presses the edge of the body radially inwards and perhaps
resiliently
deforms the same. This groove portion of the cover which constitutes the
groove
passes over radially inwards into the main portion of the cover, i.e. the
central
3 5 portion, while passing over on the periphery into a connecting portion
which is
located on the periphery of the wall and directed to the outside and downwards
to
the latter in a parallel or inclined fashion, e.g. with an increasing
distance.
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At the lower end the connecting portion passes over into a cover edge that has
a
forked or U-shaped cross section in particular with one or a plurality of
downward
directed free ends, the sealing webs.
By means of a tensioning device these sealing webs can be pressed with their
free ends against an upward directed sealing surface that constitutes the
upper
side of a flange protruding outwards from the wail of the body.
1 o The annularly encircling sealing surface against which the sealing web or
webs
press can extend horizontally, hence precisely vertically to the longitudinal
direction of the container, which usually is the axis of symmetry of the body
and
the cover, or it can be declined to the said axis, for example by declining
radially
from the outside to the inside, hence with an increasing distance in the
longitudinal
direction to the free end of the edge of the body.
The pressing of cover and body against each other, in particular at both
sealing
points, is effected by a tensioning device, in particular by snap-in straps
that are
integrally formed e.g. on the cover and distributed separately over the
2 o circumference as described above.
The snap-in straps have a groove as snap-in recess that is radially open to
the
inside and provided with inclined flanks, whose internal surfaces gain an
increasing distance to each other from the bottom of the groove towards the
open
end, i.e. in the assembled state radially from the outside to the inside.
Likewise, the rears of both the cover edge and the flange, which are turned
away
from the sealing surface, are formed in an inclined manner in the same way:
3 o The upward directed rear of the cover edge therefore declines from the
inside to
the outside, while the downward directed rear of the flange inclines from the
inside
to the outside according to the mutual inclination of the internal flanks of
the snap-
in recess of the tensioning ring.
3 5 The probability of both sealing points resting against each other in a
tight manner
is increased considerably by a movability of the elements that constitute both
sealing points either on the side of the cover or on the side of the body.
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_7.
In practice the annular flange is arranged 10 mm to 100 mm, in particular 30
mm,
beneath the edge of the body and protrudes radially outwards by 10 mm to 50
mm, in particular by 20 mm. The encircling sealing webs, which may be arranged
on the annular flange of the body or on the cover edge, have a height of 1 mm
to
mm, in particular of 3,5 mm, and a width of 1 to 10 mm, in particular of 3 mm.
c) Embodiments
In the Figures a detailed description is given of embodiments according to the
invention with different dimensional relations between cover and edge of the
body,
wherein:
Figs. 1: show the cover placed on the body in the released and in the
tensioned state at a great axial extension of the cover and
Figs. 2: show the cover placed on the body in the released and in the
tensioned state at a small axial extension of the cover,
Figs. 3: show a third variant of the container and
Fig. 4: shows a perspective view of the closed container.
Figures 1 to 3 each show a sectional view along the longitudinal direction 20,
i.e.
the axis of symmetry 10, of body 1 and cover 2 when resting against each
other,
that is in Figures a and c with the cover being loosely placed on and in
Figures b
and d with the cover being tensioned against the body. Figures c and d are
sections in the portion of the snap-in straps, while Figures a and b represent
3 o sections in the circumferential portion in-between, as can be seen in
Figure 4.
The constructions of Figures 1 to 3 have in common the basic design of the
cross
sectional form of the cover, in particular of the cover edge, and of the upper
part of
the wall of the body 1: Seen in top view both the cover and the body are
3 5 symmetrical to the axis of symmetry 10, which shall define at the same
time the
longitudinal direction 20 so that containers are formed that are closed over
the
CA 02406653 2002-10-25
circumference wherein the only side of the body that is open can be tightly
closed
by the cover. As a rule body and cover are rotationally symmetrical.
By preference, the wall 7 of the body 1 has a smooth surface on the inside to
facilitate the filling, emptying and cleaning of the inside of the container.
On the periphery, axially offset backwards and also radially spaced outwards
from
the free end of the edge of the body 1 a, the body 1 has an encircling annular
flange 8 that protrudes radially outwards and is in addition located at a
lower level
1 o than the central portion of the cover 2.
The edge of the body 1 a, hence the wall above the annular flange in
particular,
can be slightly thicker than below the annular flange, but usually it is not
thicker
than 3 mm.
In cross section the cover 2 has in the radial portion of the edge of the body
1a a
U-shape or V-shape with an annular groove 6 that is open downwards, i.e.
towards the body, with which the cover 2, being the first sealing point 4, can
be
placed on the edge of the body 1.
Radially inside this U-shaped or V-shaped groove portion 2c the cover passes
over integrally into its central portion 2d, which consequently lies on a
lower level
with respect to the groove portion 2c. The radial external flank of the groove
portion 2c is extended either in the axial direction or in a flaring fashion
by means
2 5 of a connecting portion 2b at whose lower external free end the cover edge
2a is
integrally formed. When being placed on, the latter is therefore still
disposed
below the central portion 2d of the cover in the axial direction.
In total 4 snap-in straps 33 that are distributed over the circumference
protrude
3 o downwards in the axial direction from the external end of the cover edge
2a.
These snap-in straps serve to engage with the annular flange 8 whereby the
cover
is kept resting tightly against the body in the engaged state.
In addition, the cover edge 2a has encircling concentric sealing webs 11 b, 11
c,
3 5 which are directed downwards and lie radially inside the snap-in straps 33
but in
one preferred embodiment they extend concentrically to each other only in the
portion between the snap-in straps 33 and in the circumferential portion of
the
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- 9 -
snap-in straps 33 they are combined to a single sealing web 11 b' whose radial
width preferably corresponds to the total width of the sealing webs 11 b, 11 c
including their mutual spacing.
When the cover is tensioned against the body the sealing is to take effect at
least
at the first, preferably at two different sealing points 4, 5:
The free end of the edge of the body 1 a that rests against the groove 6 of
the
cover 2 represents the first sealing point 4. The sealing webs 11 b, 11 c or
11 b' of
1 o the cover edge 2a, which rest on the upper side of the annular flange 8 of
the
body, represent the second sealing point, which is divided by the mutually
concentric sealing webs 11 b, 11 c into partial sealing points 5a, 5b over the
major
part of the circumference.
Due to the fact that the pressing of the sealing web 11 b' against the annular
flange 8 is especially strong in the portion of the snap-in straps 33 a single
sealing
web suffices in this portion. In the remaining circumferential portions the
two
concentric sealing webs serve the purpose of increasing the sealing safety.
2 o As can be seen in Figures c and d respectively the tensioning by means of
the
snap-in straps is effected in that the snap-in straps 33 have a snap-in recess
32
that is radially open inwards and located immediately below the sealing web
11b'
and corresponds in its shape and dimensioning with the cross section of the
radial
free external end of the annular flange 8, which is not webbed in this portion
but
2 5 preferably has a solid design.
As shown in Figures d respectively, the flanks of the snap-in recess 32, which
run
outwards towards each other at an angle according to the sealing surface 12b
and
the rear 14 of the annular flange 8, are formed on the upper side by the
sealing
3 o web 11 b' and on the underside by a bulge in the snap-in strap 33. The
radial
internal side of the bulge therefore forms an inclined guide surface 35, along
which the radial utmost edge of the annular flange 8 slides when the cover is
being pressed on from above whereby the snap-in strap 33 is deformed radially
outwards until the lower bulge snaps over the annular flange 8 and the latter
35 engages in the snap-in recess 32 of the snap-in strap 33. In this state the
annular
horizontal sealing surface 12b, which represents the upper side of the annular
flange 8, is being pressed on from above by both the sealing web 11 b' in the
CA 02406653 2002-10-25
-10-
portion of the snap-in straps 33 and the sealing webs 11 b and 11 c in the
other
circumferential portions. The smaller free end 34 of the snap-in strap 33,
which
protrudes downwards from the bulge, serves - also because of the sufficient
distance to the periphery of the wall of the body 1 - to be gripped from
behind with
a finger in order to pull the cover 2 radially outwards and thus release the
same.
Here it is of importance among other things that the cover edge 2a with its
sealing
webs 11 b, 11 c is in itself designed relatively stable. The same applies to
the
groove portion 2c, which may have at least a double wall thickness especially
in
1 o the portion of the groove bottom compared to the normal wall thickness of
the
central portion 2d for example and which may furthermore be reinforced by an
additionally stabilizing extension 2e located on the rear of the groove, i.e.
facing
upwards.
Compared to this the cover edge 2a is in fact movable with respect to the
groove
portion 2c, for example due to a reduced material thickness in the transition
in-
between, in particular in the transition between the groove portion 2c and the
connecting portion 2b and the connecting portion 2b and the cover edge 2a,
respectively.
Through this the cover edge 2a can for instance be bent slightly downwards
with
respect to the connecting portion or the entire connecting portion can be
pressed
slightly inwards in the radial direction with respect to the groove portion.
In addition, it is of importance that the edge of the body 1a, especially the
whole
part of the wall 7 from the flange 8 to the free end, is sufficiently stable
and has in
particular a greater wall thickness than the remaining wall 7 so that the edge
of the
body 1 a can in fact be deformed inwards or outwards in the radial direction
at its
free end but only at a relatively great expenditure of force.
Likewise, the outward directed flange 8 has a relatively stable design, in
particular
it is stabilized by means of webs 15 extending radially outwards on the
underside.
By preference, the flange 8 has a horizontally extending upper side as sealing
3 5 surface 12b, whereas the underside 14 declines from the outside to the
inside. In
the portion, in which the snap-in straps 33 of the cover 2 are placed on, the
cross
section of the annular flange 8 preferably has a solid design, in the
remaining
CA 02406653 2002-10-25
-11-
circumferential portions it is constituted by a ribbing of radially extending
webs 15
that are spaced over the circumference.
As can best be seen in Figure 4, the annular flange 8 can in addition be
reinforced
by vertical stabilizing webs 21 that protrude outwards from the wall of the
body 1
and then pass over into the annular flange 8 at the upper end while running
out
freely at the lower end. The stabilizing webs 21 only protrude radially
outwards to
such an extent that they do not impede an embracing of the external free end
of
the annular flange 8 by the snap-in strap 33 and by preference they are mostly
1 o distributed at regular intervals in those circumferential portions that
serve to put on
the snap-in straps 33, but perhaps also in the circumferential portions
located in-
between.
Figures 1 to 3 differ from each other by the relation of the distances A or B
at
cover and body which shall be defined in the following:
These distances that are to be measured in the longitudinal direction 20,
hence in
parallel to the axis of symmetry 10, shall be defined as follows in the
released
state of rest of body and cover respectively: Distance A is the axial
extension in
2 o the cover between the bottom of the groove 6 and the sealing web 11 b, 11
c of the
cover edge 2a which protrudes furthest downwards.
Distance B shall be the distance in the body between the free upper end of the
edge of the body 1a and the upward directed sealing surface 12b of the flange
8.
2 5 However, in all cases the cover 2 rests tightly in the groove 6 of the
cover 2 at the
first sealing point 4 when the tensioning device 3 has been tensioned. This
sealing
can be supported by the second sealing point 5 on the annular flange 8.
While it is clear from Fig. 1 that distance B is somewhat larger than distance
A the
3 0 opposite is the case in Fig. 2. These different relations and the
situations resulting
therefrom may be chosen on purpose or may be ascribed to production tolerances
appearing in the production of cover or body that are usually produced by
means
of the injection moulding method.
3 5 If the cover distance A is smaller than the body distance B as in Figure 1
the
groove portion 2c of the cover, when the latter is loosely placed on, is
seated with
one flank or with the groove bottom of the groove 6 on the free upward
directed
CA 02406653 2002-10-25
-12-
end of the edge of the body 1 a without the downward directed sealing webs 11
b,
11 c of the cover edge 2a reaching the upward directed sealing surface 12b of
the
flange 8, which usually extends at a right angle to the axis of symmetry 10.
If, on account of differences in diameter, the edge of the body 1 a does not
rest in
the groove bottom of the groove 6 of the cover 2 but is spaced therefrom
radially
inwards or preferably outwards by resting against one of the flanks of the
groove
6, the distance between the sealing webs 11 b', 11 b, 11 c of the cover edge
2a and
the flange 8 will be even larger at the second sealing point 5.
As shown in Figure 1 a, the lower free ends of the concentrically encircling
sealing
webs 11 b, 11 c do not lie on the same level but due to a slight outward
inclination
of the cover edge 2a and in addition a slight declining to the outside of the
connecting portion 2b of the cover 2 the radial internal sealing web 11 b is
slightly
z 5 closer to the sealing surface 12.
Through the engagement of the snap-in straps 33, that is through an increasing
penetration of the annular flange 8 into the snap-in recess 32 of the snap-in
straps
33, the snap-in straps 33 move radially inwards as far as possible on account
of
2 o their inherent resilience and at the same time they move increasingly
downwards
due to the inclined underside of the annular flange 8. As a result the cover
edge
2a is moved radially inwards on the one hand and at the same time and/or
instead
it is moved axially against the sealing surface 12b of the flange, hence
pressed
downwards, on the other hand. This can be ascribed to the movability of the
cover
2 5 edge 2a with respect to the remaining cover 2, in particular with respect
to the
groove portion 2c and especially on account of a bending or distortion of the
individual parts of the cover about the transitions 17 or 18 that have a
smaller wall
thickness and are located on both sides of the connecting portion 2b.
3o Merely because of the radial inward movement of the cover edge 2a and
because
of the approximation of the transitional portion 2b from the inclined position
to
being parallel to the axial direction, at least one of the sealing webs 11 b,
11 c
reaches - in the strap portion of the sealing web 11 b' - with its free end
the sealing
surface 12b of the flange 8 so that an additional sealing is achieved at this
second
3 5 sealing point 5. According to Figure 1 b the sealing web 11 c that extends
radially
outwards rests against the sealing surface 12b with its entire front surface
while
CA 02406653 2002-10-25
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the sealing web 11 b that extends radially inwards only has line contact to
the
sealing surface 12b.
Due to the axial movement of the cover edge 2a the groove 6, in particular its
point of contact at the flank, is pressed against the edge of the body 1 a
also at the
first sealing point whereby an increased sealing is achieved at the first
sealing
point 4 too.
If the edge of the body 1 a has a diameter that is somewhat larger than the
groove
1 o bottom of the groove 6, the edge of the body 1 a is in addition deformed
slightly
inwards in the radial direction at its free end when the cover 2 is being
pressed on,
as can be seen in Figure 1 b for example, so that the resilient restoring
force of the
edge of the body 1 a into the released resting position additionally increases
the
sealing at this first sealing point 4.
If the sealing surface 12b does in addition not extend vertically to the axis
of
symmetry 10 but gains an increasing distance in the radial direction from the
outside towards the inside to the upper free end of the edge of the body 1a
due to
an inclined position, as drawn in Fig. 2b in a dashed line, with the point of
contact
2 o possibly moving in the direction of the groove bottom and the edge 1 a
being
deformed slightly radially, this axial tensioning effect is intensified
further.
In contrast to this in Figure 2a the distance A of the cover 2 is larger than
the
distance B of the body 1. When the cover 2 is loosely placed on, the cover
edge
2 5 2a will rest on the sealing surface 12b of the flange 8 and owing to the
weight of
the cover the cover edge 2a will thereby slightly deform about the transition
18 to
the connecting portion 2b so that only the sealing web 11 b that lies radially
inwards will rest on the sealing surface 12b and the sealing web 11 c that
lies
radially outwards will be a bit raised from the said surface.
At the first sealing point 4 the groove bottom of the groove 6 still does not
reach
the free end of the cover edge 1a, unless the latter is aligned in the radial
direction
not with the bottom of the groove but is radially offset outwards - which is
the
preferred construction - or inwards and therefore already rests against one of
the
3 5 flanks of the groove 6.
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By setting on the tensioning device 3 in the form of the snap-in straps 33 the
cover
edge 2a will at first be moved radially inwards along the sealing surface 12b
and in
addition it is effected that both sealing webs 11 b, 11 c of the cover edge 2a
rest on
the sealing surface 12b of the web 8 of the body 1.
Through this radial inward displacement the connecting portion 2b adjacent to
the
cover edge 2a is likewise displaced radially inwards whereby the edge of the
body
1 a rests against at least the radially outward lying flank of the groove 6 -
perhaps
with a radial resilient deformation of the edge of the body 1 a to the inside -
1 o whereby a sealing is effected at this first sealing point 4 too.
Another possibility is shown in Figures 3:
Whereas in the solution of Figures 1 and 2 the wall thickness of the edge of
the
body 1 a was clearly smaller than the width of the groove bottom of the groove
6 in
the cover 2, the opposite is the case in the solution according to Figures 3:
At least at its free end the wall thickness of the edge of the body 1a is so
great
that it cannot penetrate into the groove 6 to such an extent that the groove
bottom
2 o is reached.
When the cover is Loosely placed on, the edge of the body 1 a therefore
already
rests with its end portion against both flanks of the groove 6, while the
sealing
webs 11 of the cover edge 2a still do not reach the sealing surface 12b of the
2 5 flange 8. Only when the snap-in straps 33 are put on and engage in
accordance
with Fig. 3d is the cover edge 2a pulled radially inwards, but above all it is
also
pulled downwards in the axial direction onto the sealing surface 12b against
which
the sealing webs 11 b, 11 c now rest. Due to this axial tensioning the free
end of
the edge of the body 1 a is also pressed further into the groove 6 and,
depending
3 0 on the stability of the groove portion 2c, the groove is also slightly
widened. On the
side lying radially inwards this leads to a small deformation of the central
portion
2d of the cover to a bulged shape and on the side lying radially outwards it
leads
to an inclined position of the outer leg of the groove portion 2c and of the
connecting portion 2b.
However, this is compensated by the radial inward displacement of the cover
edge
2a through the engagement of the snap-in straps and by the movability of the
CA 02406653 2002-10-25
-15-
cover edge with respect to the groove portion 2c due to the longitudinal
extension
of the connecting portion 2b and/or the movability resulting from the thinned
transitions 17 and/or 18 of the connecting portion 2b with respect to the
adjacent
portions.
In the perspective representation of the assembled container, hence of one
having
a cover 2 placed on the body 1 while the snap-in straps 33 are being engaged,
the
stabilizing webs 22 can furthermore be seen on the cover 2, which extend
radially
and are distributed over the circumference between the highest elevation of
the
1 o groove portion 2c of the cover 2 and the central portion 2d that lies
lower
compared to the said groove portion. These stabilizing webs 22 are also
integrally
formed on the cover just like the snap-in straps 33. By analogy this applies
to the
stabilizing webs 21 of the body 1.
1 5 In addition, in Figure 4 in the broken up part of the cover 2 and in
Figures 1 a, 1 b it
is shown that the edge of the body 1 a can be supported on the periphery by
additional stabilizing webs 23 which extend radially and are located in the
angle
between the periphery of the edge of the body 1a and the upward directed
sealing
surface 12b of the annular flange 8. The radial extension outwards as well as
2o upwards towards the free end of the edge of the body 1a has to be limited
in such
a way that these stabilizing webs 23 do not hinder a complete engagement of
the
cover 2 including the engagement of the snap-in straps 33.
30
CA 02406653 2002-10-25
-16-
LIST OF REFERENCE SIGNS
1 body 12a, b sealing surface
1 a edge of the body 13 rear
2 cover 14 rear
2a cover edge 15 webs
2b connecting portion 16 bottom
2c groove portion 17 transition
2d central portion 18 transition
2e extension 19 tensioning groove
3a, 3b 20 longitudinal direction
tensioning
device
3a groove 21, 22, 23 stabilizing webs
4 first sealing point 31 snap-in projection
5 second sealing point 32 snap-in recess
5a, 5b 33 snap-in straps
partial
sealing
point
6 annular groove 34 free end
7 wall 35 guide surface
2 0 8 annular flange
9
10 axis of symmetry A = cover distance
11a, b, c sealing web B = body distance
30
