Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
Closure caP of plastics material
The invention relates to a closure cap comprising
plas~ics material for closing the mouth of a container9
comprising a substantially cylindrical cap wall portion and
a cap end portion 9 having at least one annulax seali.ng lip
which is intended for sealing the mouth o~ the eontainerO
The invention also relates to a con-tainer closure means
comprising such a c~osure cap which can be fitted OD a mou~h
of a container and whi~h is intended for sealing to a
substantially cylindrical outsi~e wall portion of the mouth
10 of the containerO
Closure caps o that kind7 ~hich are used in particular
for bottles containing .
carbonated refreshing beveragesp are already known in many
different forms9 Between the bottler and the cvnsumer9 drinks
lS bottles are subjected to many fluctuations in temperature,
vibration and changes in positionD and must therefore have a
closuxe means which provides a reliable seal~ Annular sealing
lips which co~operate with the ~utside of the mou-th of the
container have already been pxoposed7 to provide a reliable
seal. Thus for example the present applicantsl German laid-
open application (~OS~ No 26 4~ 845 discloses an arrangement
in which the sealing lip is bent upwardly when the ~crew cap
is sc~ewed onto the container~ or the present applican-tsl
Swiss patent speciication No ~07 702 discloses an arrangement
which has a sealing lip extending substantially parallel to
the wall pvrtion of the capO US ~atent speeification No
3 360 149 discloses a screw cap wherein ~n inclined sealiny
lip co~operates wqth a peripheral recess ox chamfer on the
mouth of the container~ Britlsh patent specifi~a*ion No
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1 229 322 proposes a pexipheral sealing lip which is at any
rate arranged on the cap ~nd portion and which is pressed
outwardly when the cap is screwed into place, similarly as
in the arrangem~nt disclosed in Swiss patent specification
No 607 70Z.
A serious problem with all kno~n external sealing
arrangements is that the mouths of containers suffer from
large fluctuations in tolerancesO In addition; it is not
possible reliably to predetermine whether such sealing lips
are bent back when the cap is screwed on, or whether they are
expandedJ or whether for ex~mple the container does not even
bear against the lipsO
The problem of the present invention is theref~re to
provide a closure cap of the kind set forth above, wherein the
sealing lip engages against the mouth of the container in the
same manner, even when there are larye fluctuations in -tolerances~
According to the invention9 this problem is solved by the
following combination of features: the sealing lip is arr~nged
on the cap wall p~rtion andJox on the cap end portion and is
direc-ted at an inclined angle inwardlyl reducing in diameter; at
the location of its smallest diameter, the sealing lip has a
sealing portion which is of rounded cross-section; below the
sealing portion the sealing lip has a substantially funnel-
shaped outwardly extending enlargement, the lar~est diameter
of which is larger than the outside diameter of the mouth of
the container fox which the closure cap is intended; and the
plastics material has elasticity properties such that the
sealing lip can be expanded sleeve-like outwardly to receive
the mouth o~ the container.
The container closure means, that is tc say9 the
co-operation of the closure cap and the rnouth opening of the
container, is characterised by the following features:
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the sealing lip is arranged vn the cap wall portion andlor
the cap end portion an~ is directed a~ an inclined angle
in~ardly~ reducing in diameter~ the smallest inside diameter
before being screwed on being smaller than the outside
diameter of the mouth of the container9 at the lvca~ion of
its smallest inside diameter~ *he sealing lip has a sealing
portion which is of rounded cross-section; below the sealing
portion the sealing lip has an enlargemen-t which extends
outwardly in a substantially funnel-like shape~ wherein the
diameter in the region o~ the lower edge of the funnel-like
enlargement or the entry portion before being screwed on i5
larger than *he outside diameter o the mouth of the container~
The above-indicated arxangement of the funnel-shaped
enlaxgement on the seali~g lip will be seen to ensure that the
sealing lip always comes to bear against the outside of the
mouth of the container~ is not bent upwardly even when *here
is an excessive outside diameter on the mouth ~f the
container, and in particular is also not displaced or
irxegu~arly bent back~ wh n the cap is applied tv -the mouth of
the containerO B~ virtue of *he rounded sealing portion on
the sealing lip~ the sealing lip has a line of sealing action
which is the same in all cases and which extends arQund the
outside wall portion of the mouth of the container~ irrespective
of the inclined positioning of the sealing lip~ It will be
seen that the sealing lip can occupy a different inclined
position, depending on the respective outside diameter of the
mouth of the con*ainer~ Depending on the inclined posi-tion of
the sealing lip~ the line of sealing ac-tion against the mouth
of the container will be somewhat higher or somewhat lower.
The essential consideration in this connection is tha-t the
funnel~like enlargement has an entxy portion which in cross-
section is of a curved configuration which extends subs-tantially
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at an anale9 relative ~o ~he longitudinal axis of the cap
wall portion,/ ~ ~ the norm~l to each part of the entry
portion extends below the centre of rotation of the sealing
lip ~r the axis which is neutral in bending of the sealing lip
S cross-section in the region ~ the j~in between the sealing
lip and the cap end portion or the cap wall portion~
In this respeet, the expression entry portion is intended
to mean that region of the funnel-like enlaraement which is
intended for continuous insertion of the mouth of the container 9
10 while at the s~me time expanding the sealing lip. It will be
appreciated that the sea1 ing lip may be in the form of an
entry portion in the entire region of the funnel~like
enlargement~ Particularly when the se~ling li~ is to be for~ed
with a somewhat thiekex cxoss-section howevex~ only a part of
the side of the sealing lip, which is towards the container
mouth~ may be in the form o an entry portion.
It will be seen that the centre of rotation of the sealing
lip may be readily ascertained in a cross-sectional vi~w of the
sealing lip and cap wall portion or cap en~ portion. That point
is concerned with the neutral axis i~ the interior of the
sealing lip which, upon bending *hereofJ is not subjected either
to a tensile load ~r to a compression load9 and remains ~neutral~O
In the case of sealing lips of which the top and bvttom extend
parallel to each other~ the neutral axis coincides with the
cen~re line of -the cross~section o the sealing lipo When the
sealing lip is of a cross-section which co~verges at an angle 7
the neutral axis generally coincides with the an~le bisector.
It wi.ll be seen that the man skilled in the art will not find
any problem in definin~ the neutral axis (also re~erred to as
the zero line) and the ~ ; n~y centre of rotation in the
region in which the sealing lip joins to *he cap wall poxtion or
the cap end portion respe~tively. The precise point may be
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established with a s~fficient degree of accuracy or example
by joining together the two "points vf origin" ~f the sealing
lip on the cap end portion ~r the cap wall portion, and by
considering the point of intersection of that line with the
centre line or the neutral ~xis of the cross sectivn of the
sealing lip9 as the centre of rotation. X* will be appreciated
that it may also be defined by empirioal tests, for example by
showing Uunbent" and ~Ibent~i sealing lips on a split view
projector. If diff erenc s are found between empirical
definition and yraphic definition9 then for reasons o saf2ty9
the front centre of rotation~ that is to say~ that which is
closer to the entry portion, can be used~ If the entry portion
is in -the shape of a truncated cone9 that is to Say9 i5 in the
form of an inclinedly extending straight line in cross section,
the normal to that s*raight line may be readily defined, ~hen
producing an image of the cross sectionO If the entry portion
is entirely or partially in the fo~m of a curve ~concave or
convex), the normal to each entry portion may be gr~phically
represented by first applying a tangent to the c~rved portion
to be defined, and *hen drawing a line normal to the tangentO
If the surface of the sealing lip and/ox the entry porti~n
has an irregular suxface, as may occur ~or example by the
provision of circulaxly extending grooves in oxder to enhance
the sealin~ action, then it will be appreciated that the
opexation of defining the above-mentioned normal is not based
on the configuration of the "micro-grooves", but on *he general
curve configuration of the entry portion~ against which the
mouth of the container bearsO
. In some situations of use9 it is advantageous for the
point of attachment of the sealing lip to the cap end pvrtion
to be arranged at a spacing from the cap wall por*ion and for
the mou*h of *he containex, in the container closure means, to
have peripheral I reduced-diamet~r channel or chamfer3 for
receiving the sealing lip.
~ ox production process reasons, it is easier to provide
only a relatively small portion with small tolerances, on the
mouth of the bot~le. Tha* portion is in the for~ of a channel
or cha~fer 50 that it will be seen that the sealing lip must
also be of smaller diameterp at its point of attac}~enta By
virtue of that arrangement, the above-mentioned point o
attachment is shifted entirely onto the cover portion, ~hic~
possibly results in the sealing lip having better resiliency.
Tha* arxangement is particularly sui~able for cont~iner mouths
of large di~meters~ wherein *here is sufficient spaceO
A particularly advantageous arrangement and configura~ion
in respect of the sealing lip is achieved i~ the sealing lip
îs arranged at an angle of at most 45 with respect to the
wall portion of the cap. In this way) the sealing lip may be
arrange~ on the inside of the scxew cap~ thereby saving space,
although it is nonetheless capable of accommodating wide
fluctua*ions in tolerances a~ the mouth of the container. If
the funnel-shaped enlargement extends a* an angle of at moSt
45 with respect to the axial centre line9 the sealing lip is
-- reliably expanded outwardly without being bent back and without
the need to apply a large am~unt of force when fitting the cap
ln pos~ tion .
The action of the sealiny lip may be enhanced in some
cases by an abutment means being provided on the cap end
portion, within the sealing lip~ to delimit the relative
position of the cap end portion with respect to the mouth of
the containe~. In a bottling plant~ closure caps are fitted
onto the mouth of the container by machine~ by applying a aiven
torque. In this respect, the abutment means mak~s it easier to
accurately define and adjust the torgue required~ and ensures
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that the sleeve-like ring is in the same position, at a
spacing f~om the upper edge of *he mouth of the container.
An additional sealing action can be achieved by the
abutment means being in the form of a concentric porti~n
~hich co-operates ~ith the top of the mouth of the containér~
The outside surfaces of container mouth structures sometimes
have such severe damage thereto that the sealing lip on the
outside can no longe~ properly pexform its function~ Therefore 9
an additional sealing portion enhances the reliability and
security of the en~ire closure means~ The safety factor in
regard to the sealing action can be further enhanced by the
closure cap having an inner sealing means which pro~ects into
the mouth of the container~ In this xespect~ in particular
the combination of the various sealing systems gives a closure
cap which has a reliable and satisactory sealing effec-tO
The flexibility of the sealing lip and the sealing action
of the sealing lip may be increased by providiny a peripheral
depressi~n or recess in the cap end portion, on the inward
side. The depression or xecess prevents the f~rmation of
cracks in the sealing lip matexial, ev~n when the sealing lip
is severely stre*chedO
The spring action of the sealing lip against the m~u th
of the contai~er ~ay be maintained in a particularly reliable
~ashion by virtue of the inside diameter at the location at
25 which the ~ealing l~ o~sthe cap end portion being larger -than
~he ou~side diameter o the mouth-of the container. The above~
mentioned spring action may be fur~hex increased by the sealina
lip being rigidly connected to *he cap end portion in such a
way that i-t can be pressed against the outside wall surface of
the mouth of the container by the curvature of the cap end
portion~ which occurs when an internal pressure is produced~
The sealing lip will be pressed ~gainst the outside wall surface
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i606
of the mouth o the containex to an increas~d degree~ in
propo~tion to the screw cap being more firmly scr~wed on-to
the mouth of the container or in proportion to the increased
curvature which is produced in the cap end portion when the
S cap is screwed onto the mouth of the container~
Embodiments of the invention are described in greater
detail hereinaftex and illustlated in the d~awings in which:
~ igure 1 shows a sectional view on an enlarged scale of
par~ of a closure cap according to the invention 9
Figure 2 shows the cl~sure cap shown in Figure 19 on
the mouth o a container7
Figure 3 shows a modified embodime~t of the inven*ion,
~igure 4 shows a v~ew on an enlarged scale of a sealing
lip having the featurès of the invention~
~igure 5 shows ~he sealing lip of Figure 4 in a position
of engagement with the mouth of a containe~ and
~igure 6 shows a sealing lip at a spacing from the cap
wall portion with a channel or chamfer on the mouth of the
container~
Figure 1 shows a closure cap comprising a substantially
cylindrical cap wall po*tion 3 and a cap end portion 40 The
inside of the cap ~all portion 3 is provided wi-th a screw thread~
A sealing lip 5 which extends at an inclined angle inwa~dly is
disposed approxima-tely in the region of the join 6 between the
cap end p~rtion and the cap wall poxtion. The sealing lip is
at an angle ~ of for example 25 to 30 with respect to ~he ~ap
wall portion 3~ A rounded sealing portion 7 is disposed in the
regio~ of the smallest inside di~meter A of the s~aling lip 50
Below the sealing portion 7 9 the sealing lip has a funnel~ e
enlargement 9 whio~ is at an angle ~ of 30 with xespect to the
~axial centre line ~ (See Figuxe 4)0
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- Provided on the inside of the sealing lip 5 is a
concentric abu*ment means 10 for delimiting the scxewing-on
n~ovement of the capO ~n additional inner sealino means 13
seals against th~ inside of the mou*h 2 of the container~ as
can be particulaxly clearly seen from ~igure 2. The closure
cap may be provided in per se known manner with a guarantee
strip 15 which mus~ be removed by the consumer before the
container closure arrangement is op~ned for the firs~ timeO
The lower edge 16 of the ~unn~l-like enlargement 9 is of
a diameter D which, before the cap is screwed on, is in any
case already larger than the outside diameter B o the ou$si.de
wall portion 8 of the mouth 2 of the container~ That ensures
that the sealing lip 5 is bent outwardly~ as shown in ~ig~re 2,
and bears against the outsid~ wall portion 87 by means of its
rounded sealing p~rtion 7.
If possible, the sealing lip 5 should not be b~nt outwardly
by.the mouth of *he container *o such an exten* that it extends
virtually parallel *o the outside wall portion 8 of the mouth
of the containerO I~ that happens~ there would be th~ danger
that the sealing portion between the mouth of the container and
the sea~ing lip would no longer be linear but would be a
sealing area~ Xhat may be reliably prevented by the diameter C
at the location 14 at which the sealiny lip is attached to the
cap end portion 4 being larger than the outside diameter B of
the outer wall portion 8 of the container mouth. In this way9
when the closure cap is screwed onto the mouth of the container
the sealing lip 5 is always slightly incIined inw~rdly so that
there cannot be a sealing portion which seals over an area, but
instead~ the co~operation between the cylindrical ou~er wall
portion 8 of the mouth of the container and the rounded sealing
portion 7 of the sealing lip 5 always maintains a linear sealing
region~ with constant sealing properties~
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3~i ~
~ i~ure 2 shows the screw cap 1 in its condition of being
fully screwed into place on the ~outh of a containerO In this
conditionJ the top 17 of the mouth of the container bears
against the concentric abutmer3t means 10, whexeby the cap end
portion 4 is pressed slightly upwardlyO The cay end portion 4
is ormed into a curved configurationg to a greater or lesser
de~ree~ depending on the tvrque applied to screw the cap into
place. By virtue of suitable dimensioning in re~pect of wall
thickness and the location of attachment thereof 7 the sealing
lip 5 is rigidly connected to the cap end portion 4 in such a
way that the sealin~ lip S is pressed inwardly in the direction
indicated by ~he arrow X, when the cap end portion is of a
curved configuration. It will be seen that this can enhance
the effect of the sealing lip~
Figure 3 shows a m~dified embodiment wherein a further
sealing portion 11 is arranged within the sealing lip. The
further sealing portion 11 simultaneously performs the function
of an abutment means9 for restricting the screwing ~ovementO
In ordex to avoid material stressing and thus cracks in the
sealing lip 5 when the closure cap i5 screwed into place 9 a
depression or recess 12 is provided in the cap end portion 4,
on the inside of the sealing lip,D ~his is particularly
advantageous because there is a relatively short distance
between the sealing portivn 7 where the sealing lip S is most
stretched~ and -the c~p end porti.on 4. That distance is
ef~ectively increased by the provision o~ the depression 12 3
thereby increasing the stretchability of the eap in the region
of the sealing portion 70 That increases the possible number
of materials that can be selected for use, ~nd in addition -the
sealing lip is capahle of adapting to wide fluctuations in
tolerances in respect of the outside diameteI B ~see ~igure 2)
of the mouth of *he oont~iner~ -
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- The sealing lip S shown in ~igure 3 is of a so~ewhat
diferent CQnfi9Ura*iOn from that shown in F`igure 1~ Howe~er~
it performs the same functionO The two sealing lips 5 and 11
and -the inner sealing means 13 togethex form a sealing system
in the upper mouth region of the container~ which ensures a
particularly xeliable and advantageous sealing actionO It
will be appreciated that it is readily possible alternatively
to use other ~ealing systems, in combination with the inclined
sealing lip 5~ The configuration of the closure cap may also
be altered as ~esired, without thereby departing from the
subject-matter of this invention~ The mouth of the container
may be inserted into the sealing lip in a particularly gentle
and trouble-ree manner~ if the closure cap and the mou-th of
the container are provided with a screw threadO Thus, it is
in particular possible to envisage *he closure cap having a
multiple internal thxead, or parts of the closure cap being
made from metal or another material. Xt is particulaLly
advantageous for the closure cap to be produced by an injection
moulding process~ using polyethylene or polypropylene~
Reerriny now to ~i~ure 4 9 a sealing lip 5 has an entry
portion 9a in the region of the funnel~shaped enlargement 9
The entry portion 9a extends between the rounded sPaling
portion 7 and a bottom flat portion 18. The drawing shows the
sealing lip in broken~line positions in which it is bent
upwardly and in which it is bent downwaxdly~ When the sealing
lip is subjected to bending, one side thereof is subjected to
a compression stress while the other side is subjected to a
tensile stress7 as is known f~om the science of the strength of
materials or stress analysis. A5 the sealing lip has
substantially paxallel side walls 9 the centre line M also
indicates the neutral axîs at which the sealing lip 5 7 when
subjected to bending, is loa~ed neither in respect of tensile
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stress nor in respect of compression stressO The centre or
point of ~otation D about which the sealing lip is notionally
pivoted9 that is to sayj the point D remains in its positi~n
when the sealiny lip 5 is bent, is disposed in the region of
~he connecting line V between the two join locations 1~ and 17a~
The ~urved configuration of the entry portion 9a i5 such
that the normal lines Sl *o S3 at each part of the entry
portion 9a extend beneath the c~ntre of rotation D vf the
sealing lip. That also applies in regard *o the sealing
portion 7~ In ~hat arrangement, the en-try portion 9a is in *he
form of a straight line, so that there are no problems in
representing the two normals Sl and S29 and checking -the
configuration. On the other hand~ the sealing portion 7 is of
a rounded configuration so that firs* of all a tangent must be
drawn to the respective curvature to be examined? in order then
to draw the line S3 normal to that tangent, for the portion
which is to be checked.
It will be ceen th~t the formation of the angle ~ , in
accordance with the invention9 in dependence on the centre of
xotation D of the sealing lip~ means that, when the mouth Z of
a container penetxa*es into the sealing lip S, it stretches the
sealing ~poutwardly so as to cause e~pansion thereof, and does
not press the sealing lip upwardly towards tAe cap end portion
Figure 5 shows an embodiment which is similax to that
shown in Figure 4 7 with the sealing lip 5 being illustrated in
the expanded and the une~panded conditionsO The sealing
portion 7 and the entry po~tion 9a in this arrangement are
provided with concentxically extending grooves which9 in certain
situations of use, can enhance the sealing properties of the
sealing portion 7~ It will be seen that this embodiment too
fulils the condition that the normal lines S~ ~nd S3 pass below
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the centre of rotati~n D of the sealing lip~ More
specifically, in comparison with th~ upper edge 20 of the
mouth of the container~ the grooves lg are so small that they
do not affect the distribution or pattern of forces ir. the
sealing lip 5 during the insextion movement. The grooves 19
can at best influence the friction as between the uppex
edge 20 of the mouth 2 of the container, and the en-try portion
9aO The lines S2 and S3 are thexefoxe formed in such a way
that they are drawn in rela-tion to the overall curvature and
not the ~rooves.
Figure 6 shows an ~mbodimen* as is used for container
mouths of large diameters, with sufficient space therein. The
location 14 of attachment of thP sealing lip 5 is arranged at
a certain spacing from the cap wall p~rtion 3, on the cap end
portion 4~ The transition from the cap wall portion 3 to the
sealing lip 5 is advan*ageously xadiused, as in the other
embodiments~ .
A channel or chamfer lB for receiving ~he sealing lip 5
is provided on the mouth of the container~ at a set-back
position~ The configuration 18 can be produced with
particulaxly accurate tolerances so that the same sealing action
_ can be achieved with all container closure meansO
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