Note: Descriptions are shown in the official language in which they were submitted.
-- 1 --
TA~PER--IlJDICATING PI~STIC CI~SURE
Cross~Reference To Related ApPlication
This application is a continuation-in-part of
U.S. patent application Serial No. 07/343,995, filed
April 26, 1989.
Teehnical Field
The present invention relates generally to
tamper-indicating or tamper evident packaging
~rrangements, and more particularly to a ~amper-
indicating plastic closure for a container which
functions to provide two modes of interference with the
container for ~nh~nceA tamper resistance.
Back~loulld Of ~he Inventi3n
The provision of tamper-indicating or tamper-
evident closures for containers is desirable for all
manner of consumer products, so that partial or complete
~emoval of tha closure results in clearly discernable
visible alteration thereof. Typically, closures of this
nature include an upper cap portion, and a depending
pilfer band arranged to interact and cooperate with the
container to which the clo~ure is applied. The pilfer
band is typically configured so as to fracture and/or
separate from the closure cap atte~nt to closure
removal, thereby providing clearly discernable evidence
that the container has been partially or completely
opened.
As will be appreciated, it is desirable for a
tamper-indicating closure to be as resistant as possible
to tampering or the like without visibly discernable
evidence thereof. To this end, the present plastiG
closure has been particularly configured for economical
and efficient manufacture for use on existing
- containers, with the closure being highly resistant to
tampering, consistent and reliable in performance, and
.
- 2 -
highly ~ersatila for use with a wide variety of
different containers.
Summary Of The Inventio~
The present invention relates to a tamper-
indicating plasti~ ciosure ~or a container having a
typical annular locking ring positioned adjacent to and
beneath the ~hreads on the neck portion of the
container. For tamper-indication, ~he closure includes
a pilfer band having a plurality o~ inwardly ext~n~ing
flexible tabs, with the pilfer band further including a
coacting int rference bead positioned beneath the
flexible tabs. Notably, the pilfer band ~unctions to
provide dual modes of interfering interactio~ with the
container locking ring for tamper-indication.
In accordancQ with the invention, the present
plastic closure includes a plastic cap having a circular
top wall portion, and an annular depPn~ing cylindrical
skirt portion. In the illustrated embo~; -nt, the skirt
portion includes an internal thread formation adapted
~or coaction with a mating thread formation on the neck
portion o~ the associated container for retaini ng the
closure thereon after application to the container.
The present closure further includes an
annular, integrally formed pilfer band depP~ing from
~5 the skirt portion of the closure cap. The pilfer band
is at least partially detachably connected to the skirt
portion of the cap by a plurality of circumferentially
spaced frangible ribs. In the illu~trated e~bodiment,
the frangible ribs extend between inside surfaces of the
skirt portion and pilfer band, with the ~kirt portion
and pilfer band otherwise being distin~li~he~ and
separated from each other by a circumferential score
line which extends partially into the frangible ribs.
The pilfer band includes an annular band
portion, and a plurality of circumferentially spaced,
7~
- 3 -
inwardly extDn~ing flexible tabs which extend inwardly
of the annular band portion. Notably, the pilfer band
further includes an annular interference bead ex~n~;ng
generally inwardly of the annular ~and portion, with the
inter~erence bead positioned beneath the inwardly
ext~n~ing flexible tabs.
By this arrangement, two mode~ of interfering
interaction, for tamper-indication, are provided between
the flexible tab~ and the annular locking ring o~ the
container. During application of the closure to the
container, the ~lexible tabs are bent upwardly to an
out-of-the-way disposition as the pil~er band moves
downwardly past the container threads and locking ring.
As the closure is-fully seated on the container, the
~lexible tabs mov~ past the container locking ring, and
due to their re~ilient memory, move inwardly to assume
an angularly generally upwardly and inwardly disposition
relative to the annular band portion. In this
disposition of the flexible tab~, they are positioned
for interfering engagement with the generally downwardly
facing surface of the container locking ring, whereby in
this first mode of inter~erence, the free end portions
~f the flexible tabs engage the lo~ki ng ring for
~racturing the franqible ribs which at l~ast partially
detachably connect the pilfer band to the skirt portion
o~ the closure cap. Clearly visible evidence of opening
is thus provided.
In a second mode o~ interfering interaction,
the flexible tabs cooperate and coact with the
interference bead of the pilfer band to again
interferingly engage and coact with the container
lo~kin~ ring. In thi6 mode of op~ration, the ~lexible
tabs are engageable with the container lo~kinq ring in
the event that the flexible tabs assume an angularly
downwardly and inwardly ext~n~ing disposition relative
-- 4 --
to the annular band portion of the pilfer band. In this
orientation, the ~lexible tabs are engageable with the
container locking ring by disposition between the
locking ring and the annular interference bead. The
flexible tabs and interference bead are dimensioned
relative to the container locking ring so as to r~sist
opening muv~ ient of the closure, thereby fracturing the
frangible ribs joining the pilfer band to the skirt
portion. Again, clear visua~ evidence of opening is
1~ achieved.
In accordance with alternate, illustrated
~ ho~; -nts of the present closure, a scoring bead can
be provided which extends circumferentially on the
inside surface of the closure, and which desirably acts
to support the interior of the closure during formation
of the circumferential score whic~ distinguishes the
pilfer band from the skirt portion of the closure.
Additionally, at least some of the frangible ribs of the
construction can be configured to extend on the inside
surface of the pilfer band between adjacent ones of the
flexible tabs. Such ribs desirably function to center
the pilfer band on the associated container with respect
to the locking ring thereof, thus further enhancing
tamper resistance. If desired~ a plurality of
~5 circumferentially spaced prestressing projections can be
provided on the inside of the pilfer band, with these
pro;ections being engageable with the container locking
ring for prestressing the frangible ribs joining the
pilfer band to the closure skirt portion. This
prestressing arrangement can desirably promote failure
of the frangible ribs in the intPnfle~ ~nnPr.
Numerous other features and advantages of the
present invention will become readily apparent from the
following detailed description, the acc ~nying
3S drawings, and the appended claims.
Brief DescriPtion Of The Drawings
FIGURE 1 is a side elevational view, in
partial cross-sec~ion, of a tamper-indicating plastic
closure embodying the principles of the present
invention applied to an associated container;
FIGURE 2 is a cross-sectional view o~ the
novel tamper-indicating alosure;
FIGUXE 3 is a fragmentary, side-elevational
view, in partial cross-section illustrating application
of the novel closure to the associated container;
FIGURE 4 is a view similar to FIGURE 3
illustrating the closure after application to the
associated container, and in a poæition ~or providing a
first mode of interPering engagement with the container;
FIGURE 5 is a view similar to FIGURE 4,
illustrating the closure in position for effecting a
second mode of inter~ering engagement with the
associated container;
FIGURES Sa and 6b are views similar to FIGURE
5, further illustrating the second mode of interfering
engagement of the closure with the associated container;
FIGURE 7 is a fragmentary, cross-sectional
view of a further embodiment of the present tamper-
indicating plastic closure, and
~5 FIGURE 8 is a view similar to FIGURE 7
illustrating another embodiment of the present tamper-
indicating closure.
FIGURE 9 illustr~tes a further e~bo~; ~nt of a
tamper-indicting closure;
FIGURE 10 is a cross-sectional view of the
closure illustrated in FIGURE 9; and
FIGURE 11 is a ~ragmentary, cross-sectional
view taken along lines 11 11 of FIGURE 10.
~etailed Descxiption
While the pre~ent invention is ~usceptible of
embodiment in various forms, ~here is ~hown in the
drawings and will hereinafter be described a presently
preferred embodiment, with the understAn~;ng that the
present disclosure is to be considered as an
exemplification o~ the inven~ion, and is not intended to
limit the invention to the specific embodiment
illustrated.
With reference first to FIGURE 1, therein is
illustrated a plastic closure 10 embodying the
principles of the present invention. Closure 10 can be
made by various injection-molding or compression-molding
techn;ques, and it can be formed in accordance with the
compression-molding te~hniques taught in U.S. Patent No.
4,497,76S, which is incorporated herein by r~ference.
As illustrated, closure 10 includes an upper
generally cup-shaped closure cap 12 including a circular
top wall portion 14, and a depenfl;ng, annular
cylindrical skirt portion 16. Skirt portion 16
preferably includes an internal thread formation 18
configured for thre~ing engagement in cooperation with
tha threads T of an associa~ed container C to which the
closure is fitted. If desired, the plastic closure can
be provided with an associated sealing liner, such as
illustrated in the above-referenced patent.
The present closure ~urther includes an
annular pilfer band 20 dep~n~ln~ from and at least
partially detachably connected to skirt portion 16 of
the closure cap. Pilfer band 20 preferably comprises a
continuous annular band portion 22 arranged in
substantial vertical alignment with ~kirt portion 16.
In the preferred embodiment~ the pil~er band is at least
partially detachably connected to the skirt portion by a
plurality o~ circumferentially spaced ~rangible ri~s 24
which extend between the inside surfaces o~ the skirt
portion 16 and the band portion 22 of the pil~er band.
As shown, the pilfer band 20 is otherwise distin~; ~he~
and separated from the skirt portion 16 by a
circumferentially ext~n~ing score line 26.
In accordance with the teachings o~ U.S.
Patent No. 4,418,828, incorporated herein by reference,
score line 26 and frangible rib 24 together cooperate to
provide the desired frangible cnnnection between the
pilfer band 20 and the closure cap 12. Specifically,
the closure cap 12 and the pilfer band 20 are formed
integrally with each other during molding, with the ribs
24 molded on the inside surfaces of the skirt portion
and pilfer band. Thereafker, score line 26 is formed,
preferably by use of a scoring cutting blade, thereby
distin~lishing and separating the pilfer band 20 from
the skirt portion 16, with the score line 26 ext~n~; ng
partially into the ribs 24.
By this arrangement, the unscored, 'iresidual"
portions of the frangible ribs 24 collectively provide
the desired frangible connection between the pilfer band
and the skirt portion. If desired, an integral
connector portion can be provided between the pilfer
band and the skirt portion (such as by leaving a portion
~5 of the closure uncut by score line 26) whereby the
pilfer band rPr-inR connected to the sXirt portion 16
after fracture of the ribs. In conjunction with such a
connector portion, one or more fracturable areas can be
provided in the pilfer band itself, whereby the pilfer
3~ band 6plits and fractures during closure removal from
the associated container.
Referring now to the configuration of the
pilfer band 20, the present closure has been
specifically configured to provide a very high degree of
tamper resistance, and in particular provides two
~ 3~J~
distinct and separate modes of interfering interaction
with the associa~ed con~ainer. To this end, the pilfer
band includ~s a plu~ality of circ~mferentially spaced,
inwardly ext~n~;ng flexible tabs 28 which extend
inwardly from the annular band portion ~2 of the pilfer
band. In a current embo~i ?~t, twelve evenly spaced
tabs 28 are provided about the circumference of the
pilfer band, with each tab having a width of about 0.240
inches, and a thickness of between about 0.012 inches
and O.U20 inches. By this arrangement, the free end
portions of adjacent ones of the tabs 28 axe closely
spaced ~about 0O020 inch spacing) when the tabs extend
horizontally inwardly. ~his horizontally inwardly
exten~i ng orientation of the tabs is indicated in
phantom line, and represents the orientation in which
the flexible tabs 28 are preferably molded.
As will be further described, the flexible
tabs 28 cooperate with an annular locking ring portion L
of container C for effecting fracture of frangible ribs
24, thereby providing the desired tamper-indication. In
a first mode of interference and failure, the free end
portions of the flexible tabs are engageable with the
locking ring I,. In a second mode of failure, the
flexible tabs are configured to cooperate with an
~5 annular interference bead 30 provided generally at the
lower edge of annular band portion 22 of the pilfer band
20. To this end, the interference bead 30 is po~itioned
beneath the flexible tabs 28, with the upper, inward
edge portion of the interference bead positioned
relative to the flexible tabs so that this edge portion
is engaged by the tabs in the second failure mode. In
the preferred form, the inside diameter of the
interference bead is about equal to or slightly less
than an inside diameter collectively defined by the
;~$~7~
g
inside surfaces of tha circumferentially spaced
frangible ribs 24.
Referring now to FIGURE 3, the function o~ the
present closure will be described. During application
of the closure 10 to the associated container, the
flexible tabs 28 engage the container C and are mov~d
upuardly generally to an upwardly exte~in~, out-o~-the~
way disposition as the pilfer band moves downwardly
relative to the container threads T and the container
1~ locking ring ~. To this end, the flexible tabs 28 are
preferably provided with a thickness about equal to the
radial dimension o the frangible ribs 24, or the tabs
28 are otherwise configurad to collectively define an
inside diameter about equal to an insi~e diameter
lS collectively defined by the ribs 24.
When the closure is fully seated on the
container, the flexible tabs 28 have moved past the
container lock; n~ ring L, and thereafter, due to the
resilient memory of the plastic, assume a generally
angularly upwardly and inwardly exten~;ng disposition,
as illustrated in FIGURE 4. The flexible tabs 28 are
now in position for the first mode of interfering
interaction and ~ailure in cooperation with the
container locking ring. Specifically, unscrewing upward
~5 movement of the closure 10 relative to the container
urges the generally upwardly ~xten~in~ flexible tabs 28
into and against the container locking ring L. This
interfering engagement ~ith the ~ontainer locking ring
acts to resist the upward unscrewing movement of the
closure, thereby stressing and fracturing the frangible
ribs 24. ~racture of the ribs ~4 results in clearly
visibly ~iscernable separation of the pilfer band 20
from the skirt portion 16, thus providing a clear
indication of opening of the container.
.:
-- 10 --
In a current embodiment, each flexible tab 2
is of a generally planar confi~ura~ion, having a
thickness ~i -n~ioned between a~out 0.012 inches and
0.020 inches. However, as will ke appreciated, each
flexible tab 28 is preferably dimensioned and configured
for sufficisnt thickness, in the direction from its free
end to its base integral with the band portion 22, so as
to exhibit sufficient resistance to collapse or
deformation to thereby provide the desired interfering
interaction with locking band L. To this end, each of
the ~abs 28 may be of a non-planar configuration, such
as being slightly curved when viewed in cross-section
perpendicular to the length of each tab, or similarly,
of a generally angled or compound con~iguration when
similarly viewed. As will be appreciated, such
arrangements can act to enh~nce the "column strength" of
aach flexible tab for providing the desired interfering
engagement with locki n~ ring L.
In accordance with the present invention, the
flexible ~abs ~8 are configured for cooperation with
interference bead 30 to provide a second and distinct
mode of interfering engagement with the container
locking ring L. In the event that the flexible tabs 28
are moved from their angularly upwardly and inwardly
~5 disposition (such as by unauthorized manipulation or the
like, which is desirably inhibited by the inwardly
exte~;ng bead 30) the flexible tab~ will assume an
angularly downwardly and inwardly ext~n~i ng disposition~
as illustrated in FIGURE 5. In this orientation of the
tabs, the tabs are positioned for engagement with the
container lock~ng ring L by disposition between khe
container locking ring and the upper inward edge o~ the
interference bead 30. In this -nner~ the tab~
cooperate and coact with the inter~erence bead to again
provide interfering interaction with the container
locking ring, to thereby fracture frangible ribs 24 for
at least partially detaching the pilfer band 20 ~rom the
skirt portion 16. This action is illustrated in FIGURES
6a and 6b, where in FIGURE 6a, a flexible tab 28 i6
illustrated between the locking ring L and the
interference bead 30, with FI~URE 6b illustrating the
subseguent failure of frangible rib 24 and separation
along score line 26.
Rererring now to FIGURE 7, therein is
illustrated an al~erna~e embo~i -n~ of the pre~ent
tamper-indicat~ng closureO In most respects, this
ambodiment is the same as the previously described
ho~i ^nt, although it will be noted that th~ closure
illustrated in FIGURE 7 shows the provision of a sealing
liner 15 adjacent to top wall portion 14, and a vent
groove 17 traversing the internal thread formation 18,
with the vent groove 17 exte~ing into the cylindrical
skirt portion ~6 of the closure. The provision of one
or more vent grooves 17 facilitates venting of gas
pressure, atten~nt to closure ~, val, when the present
closure is used in connection with a container having
carbonated contents or the like.
As in the previous embodiment, the closure 10
includes a pilfer band 20 which is distinguished and at
least partially separated from the skirt portion 16 by a
circumferential score 26. Moreover, the pilfer band 20
includes a plurality (twelve being presently preferred)
of circum~erentially spaced, inwardly extPn~i~g flexible
tabs 28, again configured to provide a dual ~ode o~
interference with the locking ring o~ an associated
container. To this end, zn inwardly exten~ing
interference bead 30 i8 positioned beneath the flexible
tabs 28, with the tabs 28 being engageable with the
inter~erence bead 30 in the second mode of interaction
o~ the closure with an associated container.
- 12 -
In this embo~ t, khe frangible connection
between the pilfer band ~0 and the ~kirt portion 16 is
provided by a plurality of circumferentially ~paced,
frangible ribs 124 which extend between the inside
surfaces of the skirt portion and the pilfer band.
Significantly, at least some of the frangible ribs 124
extend on the inside surface of the band portion 22 of
the pilfer band 20 between adjacent ones of the ~lexible
tabs 28. In the illustrated embodiment, each of the
illustrated frangible ribs 124 is so configured.
This configuration of the frangible ribs 124
desirably acts to center the pilfer band 20 on the
associated container C with respect to the container
locking ring ~. By virtue of this configuration of the
frangible ribs 124, a very li~ited amount of clearance
is provided between the container locki ng ring L and the
inwardly facing surfaces of the frangible ribs 124 when
the closure 10 is fully seated on the associated
container. This desirably acts to enhance tamper-
resistance since the frangible ribs 124 thus act toprevent deformation of ~he pilfer band ~o an out-of-
round configuration, thus substantially precluding
removal of the pilfer band from the associated container
without at~en~nt fracture of the frangible ribs 124.
~5 Like the frangible ribs 24 of the previous embo~i ?nt~
ribs 124 are rendered fracturable by virtue of thP score
line 26 partially extPn~ing into at least some of the
ribs.
In the embodiment of FIGUR~ 7, an arrangement
is provided to facilitate efficient and accurate
formation of the score line 26. 5pecifically, this
embo~; -nt includes a circumferentially exte~ing
scoring bead 127 on the inside o~ ~he closure, wi~h the
scoring bead 127 preferably ext~n~i ng continuously along
- 13 -
the inside of thQ closure, and with circumferential
~cor~ line 26 positioned beneath the scoring bead.
During scoring of the present closure, a
scoring mandrel inserted into the closure is preferably
employed, with a scoring knife or the like then applied
to the exterior surface o~ the closure. For high-speed
~anufacture, it is presently preferred that position of
the scoring knife be referenced relative to the
interioxly-positioned scoring mandrel.
1~ Accordingly, it is desirable to have the
closure remain in a sub~tantially fixed position on the
scoring mandrel, without excessive deformation or
deflection duxing scoring. Otherwise, inaccurate
scoring may result.
Thus, the scoring bead 127 is configured to
securely engage and seat against the scoring mandr21,
whereby highly e~ficient and accurate formation of the
score line 26, with the desired degree of partial
cutting of the frangible rib 124, is readily
accomplished.
As in the previous embodiment, the flexible
tabs 28 are preferably provided with a thickness about
equal to the radial di -nRion of frangible ribs 1~4.
This preferred di~ensional relation permits the tabs ~8
to desirably support the interior of the closure during
scoring (when the tabs 28 are flexed upwardly against
the inside surface of the closure) in absence of the
scoring bead 127.
Efficient and accurate ~coring is furth~r
facilitated by the dispositlon of the frangible ribs 124
between adjacent ones of the tabs 128. By this
arrangement, any possible overlap of one of the tabs 12
with an adjacent frangible rib (such as by deformation
and elongation of a flexible tab att~ nt to ejection
from its molding apparatus) is avoided. Additionally,
pfs~ t~
this ex~n~e~ configuration of ~he frangible ribs 124
permits th~ score line 26 to be positioned relatively
close to the bottom edge of the pil~er band 20, which
has been found to desirably ènhance the tamper-
resîstance of the pre~ent closure, 6ince anyunauthorized manipulation or other tampering is more
lik~ly to result in fracture of one or more of the
~rangible ribs 124.
A further feature of the embodiment of FIGURE
7 concerns the formation of each of the ~rangible ribs
124 with an upper portion 125 which extends on the
inside surface of skirt portion 16 above scoring bead
127. This configuration of the frangible ribs has been
found to desirably enhance the colu~nar strength of the
overall closure, which facilitates high-speed ejection
fro~ ~he associated molding apparatus.
Referring now to FIGURE 8 t therein is
illustrated a further alternate embodiment of the
present closure. In most respects, this embo~i -nt is
like that described above and illustrated in FIGURE 7,
although the embodiment of Figure 8 does not include a
scoring bead 127. The absence of the ~coring bead,
together with the extended configuration of frangible
ribs 124 (with upper portions 125) can enhance the gas
ventin~ characteristics of the closure~
~ wo additional features of the emho~i ?nt of
FIGURE 8 should be noted. First, thi~ embodiment of the
present tamper-indicating closure includes an
arrangement for prestressing the frangible connection
between the pilfer band 20 and the ~kirt portion 16
provided by the frangible ribs 124. Speci~ically, a
plurality of circumferentially ~paced, prestressing
projections 131 are pro~ided on the inside surface of
the band portion 20 of the pilfer band. In the
illustrated embodimentO and in accordance with the
~ ~ kJ ~ j 9
-- 1~
preferred configura~ion, the~e prestressing projections
131 are each positioned on a re pective one of the
frangible ribs 124. In the illustrated embodiment, the
prestressing projections 131 are provided on alternate
ones of the frangible ribs 124, but a fewer or greater
nu~ber of the projections 131 can be similarly provided.
Projections 131 can be provided to prestress
the frangible ribs 124 atten~nt to both application and
re~oval of the closure. During application of the
closure to the ae~ociated container, the projections 131
are engageable with the container locking ring L, thus
acting to ~rA~ and ~bell out" the pil~er band 20
att~n~nt to application. This action can act to weaken
the unscored, residual portion of each ~rangible rib
124, thereby facilitating failur2 of the frangible ribs
in the intended manner during closure removal.
Additionally, the prestressing projections 131
can cooperate with the locking ring ~ during closure
removal. In particular, this can occur in conjuncti.on
with stressing and fracture of the ribs ~24 when tabs 28
extend angularly downwardly, and are positioned between
the container locking ring L and interference bead 30.
Att~nd~nt to this action, the projections 131 provide
additional interference with ~he container locking ring,
~5 thus desirably subjecting the ~rangible ribs 124 to
additional ~tress to assure fracture and failure of the
ribs.
A further ~eature of the embodiment o FIGURE
8 concerns configuriny the pilfer band 20 ~or fracture
of the band portion 22, which is ordinarily desired, as
discussed above, in conjunction with the provision of an
unscored connector portion which integrally joins ~he
pilfer band to the skirt portion 16 after fracture of
ribs 12~. By such an arrangement, the pilfer band
:
J~?~
-- 16 --
rf -in~ joined to, but par~ially detached from, the
skirt portion 16.
To this end, FIGURE 8 illustrates the manner
in which a vertical score is preferably formed in the
pilfer band 20. Speci~ically, an external ~coring knife
is preferably applied to the pilfer band so as to form
one or more scores extending to a depth as illustrated
in phantom line at 133. Preferably, ~uch vertical
scoring is provided between one of ~he ~lexible tabs 28
1~ and an adjacent frangible rib 124, so that such vertical
scoring does nok extend into either the tab 28 or the
rib 124.
Notably, it is preferred that the verti~al
scoring extend partially, but not completely, into the
interference bead 30, to thereby define a fracturable
residual portion 135 of the pil~er band. This
arxangement preserves a desired degree of strength in
~he pilfer band, to facilitate high-speed application,
while still rendering the pilfer band fracturable in the
intended manner.
Thus, a high degree of tamper-resistance is
provided by the present closure. As will be
appreciated, various modifications and departures from
the illustrated embo~ t can be effected. For
example, ~he number, spacing, thicknç~, and
configuration of the flexible tabs 28 can be varied and
selected while keeping with the principles disclosed
herein. Similarly, while the annular interference bead
30 is preferably substantially continuou~ in nature for
providing additional circumferential hoop strength ~or
the closure, segmented or otherwi6e discontinuous
con~igurations for the interference bead can be
alternately employed. Moreover, w~ile ~he present
invention has been illustrated in the form of a one-
piece, all plastic closure, it will be appreciated that
.
- 17 -
a closure embQdying the present invention may be
composi~e in nature, such as a combination metallic and
plastic closure (with or without a separate s~aling
liner).
Referring now to FIGURES 9-11, therein is
illustrated a further embodiment of tamper-indicating
plastic closure 10~ In accordance with previous
--ho~ ~nts, this plastic closure 10 includes a cup-like
closure cap 12 having a circular top wall portion 14,
and a depPn~lng annular or cylindrical skirt portion 16
having an internal thread formation 18. As shown in
FIGURE 9, closure 10 is inten~e~ to be applied to an
associated container C having an external bead-like
locking ring L which extends circum~erentially of the
neck portion of the container perpendicular to the
vertical axis thereof. Locking ring ~ is positioned
just beneath external container threads T, with the
container C including a hand grip or handle H.
In this embodiment, the closure includes ~n
annular pilfer band 20 depPn~ing ~rom skirt portion 16
which is at least partially detachably connected to the
skirt portion by a plurality of circumferentially spaced
apart fracturable bridges 220 The fracturable bridges
can alternately be provided generally along the inner
surfaces of the pilfer band and skirt portion, such as
disclosed in U.S. Patent No. 4,418,828.
Pilfer band 20 includes an annular, bead-like
interfarence lip 24 extending circumferentially about
the inner surface of the pilfer band 20. Notably,
interference lip 24 does not extend perpendicularly to
the vertical axis of closure 10, but rathar extends in a
plane arranged at an acute angle relative to the
vertical axis of the closure. In the pre~erred form,
this plane is arranged at an acu~e angle in the range of
about 1 degree to about 5 degrees relative to the
. .
18 -
closure axis. While th~ in~er~erence lip as shown is
ext~n~ing continuously about the inner surface o~ the
pilfer band 20, it should be recognized that the lip 24
may be otherwise confi~ured, 60 as to extend
discontinually about the inner surface ~uch as by the
provision of a series of seyments, lugs, or lik~
projections. Whether the interference lip 24 is of a
continuous or discontinuous configuration, it is
eontemplated that the lip extends in a skewed or non-
perpandicular relationship to the vertical axis of theclosure.
By virtue of the skewed configuration of the
interference lip 24 with respect to the closure axis,
non-circular engagement is created between the
interference lip and the locXing ring L of the container
duriny application and removal of the closure.
~on~equently~ stresses created on the closure, are non-
uniform about the circumference of the closure.
During application, this non-uniform stressing
desirably results in the deformation of the pilfer band
20 to an out-of-round, non-circular configuration, i.e.,
to a generally elliptical or oval shape. ~his
de~ormation in the pilfer band facilitates movement of
the interference lip past the locking ring L during
application of the closure to the container, thereby
reducing the ~orce required for application and
minimizing stresses created on fracturable bridges 22.
During closure removal, the interference lip 24 again
coop~rated with the containsr locking ring ~ to create a
non-uniform stressing of the pilfer band 20, and in
particular provide a progressive stressing of
fracturable bridges 22. During closure removal, that
portion of the interference lip ~ closest to the top
wall portion 12 of the closure first engages the locking
ring L of the container. This results in localized
-- 19 --
stressing in the r~gion of thi6 initial engagement. In
~his manner, progressi~e failure of the bridges 22 can
be induced.
In order to prevent the interference lip 24
from slipping over the locking xing L without failure of
bridges 22 during closure . ~val, it is desirable to
provide means for preventing the pilfer band 22 from
assuming a non-circular configuration. To this end, a
plurality of circumfexentially spaced centering ribs 26
are provided on the inside surface of pilfer band 20
abova interference lip 24. centering ribs 26 are
positioned to engage the container locking ring L during
closure removal, and thus maintain the pilfer band in a
circular configuration.
As will be appreciated, other suitable forms
of centering means can be employed, such as by the
provision of a continuous ~ing on the interior of the
closure, or by the provision of an area of relatively
reduced inside diameter just above the interference lip.
In essence, it is contemplated that a centering
arrangement be provided for engagement with lock;n~ ring
L as the interference lip 24 engages the locking ring,
to thereby prevent the pilfer band from assuming a non-
circular configuration, thus assuring the int~n~e~
fracture of bridges 22.
From the foregoing, it will be observed that
numerous modifications and variations can be effected
without departing from the true spirit and scope of the
novel concept of the present invention. It is to be
understood that no limitation with respect ~o the
specific embodiments is intended or should be inferred~
The disclosure i~ inte~e~ to cover by the appended
claims all such modifications as fall within the score
of the claims.
