Note: Descriptions are shown in the official language in which they were submitted.
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I.VIPROVED TAMPER-EVIDENT CLOSURE
FIELD OF THE INVENTION
The present invention relates to a tamper-evident closure with a thin web
S of material formed between the tamper-evident tabs.
BACKCROUND OF THE INVENTION
Tamper-e~ ident closures of various types have been used in the past on
containcrs to enable the user of a product to determine whether the container has
10 been opened. Such closures have commonly been made of aluminum or plastic.
One type of closure includes an upper cap portion and a lower security
ring or band which is attached to the cap portion by a failure line. When the cap
is removed. the closure breal;s along the failure line, leaving the ring separate
from the cap portion. Often the security ring is heatec. and rolled under a
15 shoulder of the container; plastic closures of this type are described in U.S. Patent
Nos. 3~673,761 and 4.033.472.
U.S. Patent ~os. 4.506.795 and 4,595,110 describe tarnper-evident closures
with tamper-indicating tabs which fold upwardly and inwardly and lock against
the lower surface of an annular shoulder on a container neck to retain the tamper
20 indicating means on the necl; as the cap is removed. The tarnper indicating
means has a ring to which the tabs are integrally connected at their lower outerends. The tabs are resilient and are flexed by the container finish at the joints
where they are joined to the ring. These closures may be installed simply by
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screwing them onto a container neck in a one step process. The flexible tabs
guide the closure and center it as it is lowered onto the container neck for
in~S~ tion. They do not require the holding of the closure or the container finish
to close tolerances. However, there is a small chance in such a system that
flexible tabs may turn outwardly during shipment.
There is a need for an improved tamper evident closure which may be
simply installed on a container finish and yet will not suffer the drawbacks of
inadvertent outwardly flexing tabs.
SUMMARY OF THE INVENTION
These and other needs are met by the tamper-evident closure and container
of the present invention. A tarnper-evident closure is provided for sealing an
open-topped container. A container of the present invention has an external screw
thread formed on the neck of the container and an outwardly projecting annular
I ~ shoulder formed below the screw thread on the container. A closure of the
present invention has an internally threaded closure which may be removed from
the container for dispensing the contents of the container. The closure has a base
~ all for extending across the open top of the container, an annular sidewall
integrally joined to the base wall about the periphery of the base wall and
'0 depending from it. and tamper-indicating features. The tamper-indicating features
include a pilfer ring depending from the annular sidewall and located axially invertical alignment ~ ith the side~all. a number of flexible tabs connected to the
pilfer ring capable of being bent upward and radially inward from the pilfer ring
for contacting the annular shoulder of the container during removal of the closure
'~ to prevent the pilfer ring and tamper-indicating features from traveling upward
beyond the annular shoulder with the rest of the closure. As such the pilfer ring
then breaks away from the closure. The tamper indicating features also include
webbed areas located between the flexible tabs to prevent the flexible tabs fromflexing outwardly.
The closure may be advantageously made of plastic.
The tabs in the present invention join the pilfer ring along folded joints,
and the tabs are spaced from each other in a circumferential direction. The cross-
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sectional thickness of the tabs may be subst~nti~lly equal to ~e cross-sectionalthickness of the pilfer ring portion to which they are joined. The tabs are
preferably s--bst~nti~lly rectangular in shape and project upwardly and inwardly.
The webbed areas are also subst~nti~lly rectangular in shape, however, the cross-
sectional thickness of the webbed areas is substantially less than the cross-
sectional thickness of the tabs.
BRIEF DESCRIPTI~N OF THE DR~WINGS
FIG 1 shows a side view of an embodiment of a closure of the present
invention with webbing between the tabs.
FIG 2 shows a side view of an embodiment of a container of the present
invention v.ith an annular shoulder.
FIG 3 shows a side view of an embodiment of a closure of the present
invention. with the tabs in a flexed position just prior to installation on a
I ~ container neck.
FIG 4 shows a side view of an embodiment of a closure of the prior art,
with the tabs in an undesired "tab-out" condition.
DETAILED DESCRIPTION
'0 FIG I illustrates an embodiment of a closure 2 of the present invention.
Closure 2 has a base wall l l '. Depending from the periphery of the base wall
11~ is an annular sidewall 110. The interior of the annular sidewall 110 has
threads for engaging correspondin~ threads on a container nec~. The annular
sidewall 110 is frangibly connected to a pilfer ring 125 through a weakened area
Depending from the pilfer ring 125 are a series of tabs 121a, 121b,
121c...., 121n. In this application, if an individual tab is mentioned, the term"tab(s) 121k" will be used. However, if characteristics of all of the tabs are
discussed the general term "tabs 121" will be utilized. The tabs 121 are spaced
circumferentially from each other. Between the tabs are placed webs 123a, 123b,
123c,..., 123n, which tend to tie the movement of one tab 123k to the movement
of its neighboring tabs 123(k-1) and 123(k+1). These webbed portions are
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preferably rectangular in shape so as to well-match the space between the tabs.
The webs 123 generally do not extend as far, in a downward direction, as do the
tabs 121. The thickness of the material from which the webs 123 are constructed
is also preferably less than that of the tabs 121, so as to allow a reasonable
S amount of flexibility.
FIG 2 shows an embodiment of a container 200 of the present invention
has a shoulder 204 from which a neck 203 extends upwardly. The neck 203 has
opening 205 through which the contents of the container 200 may be dispensed.
The exterior of neck 203 has threads 201 which threadingly engage corresponding
l 0 threads on the interior of the annular sidewall. Finally, the neck 203 has an
annular shoulder 202 which provides a projection which tabs 121 may push
against so as to hold the pilfer ring 125 below the annular shoulder.
~ hen the closure 2 is used to seal the open mouth of the container 200,
the closure 2 is installed by being screw-threaded onto the neck 203 of the
I S container 200.
Prior to the capping operation, the tabs 121 must be flexed inward so that
the~ e.~tend radiall~ and inwardly~ pointing towards the interior of the closure 2~
as shown in FIG 3. Once the tabs 121 are flexed inwardly, the closure 2 may be
pl~ced onto the container 200. During this installation procedure, the tabs 121, so
'O tle~;ed~ contact the threads 201 but.travel over them. The tabs 121 also travel
o~er the annular shoulder 202. Once past these obstructions, the tabs 121 flex
slightly inwardly toward the central axis of the closure 2.
This flexing of the tabs 1 1 inhibits upward motion of the closure 2
because the tabs 121 enga~e the annular shoulder 202 but may not pass back over
'~ the shoulder 202. Thus~ the tabs 121 hold the pilfer ring 125 onto the container
neck 203, which in tum holds the closure 2 onto the container neck 203 via the
weal;ened area 124.
When a user wishes to dispense some or all of the contents of the
container 200, the user rotates the closure 2 off of the container 200. This
30 rotational motion is, of course, translated into an upward force by the action of
the threads. As the closure 2 is forced upward, tension is exerted on the
weakened area 124 because the upward motion of the closure 2 is countered by
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the downward force of the tabs 121 against the armular shoulder 202. That is, the
tabs 121 keep the pilfer ring 125 at or below the level of the armular shoulder
202, while the user's rotation of the closure 2 forces the closure 2 upward.
After more rotation of the closure 2, and its subsequent upward motion,
enough tension is placed on the weakened area 124 that it ruptures and breaks.
This frangible quality of the weakened area 124 thus allows the closure 2 to be
removed from the container neck 203 while leaving in place, under the annular
shoulder 202, the pilfer ring 125 and tabs 121. The presence of the pilfer ring
125 and tabs 121. separated from the closure 2, thus alerts the user that the
closure's seal has been broken and that at least one person has gained entry to the
closure prior to its use by the user.
The presence of the tabs 121 also assist in the initial installation of the
closure ' onto the container 200. This is because the inwardly flexed tabs 121
~end to _uide the closure onto the container neck 203 during installation, even if
I ~ the alignment of the closure 2 ai~d the container neck 203 is not exact. In
particular~ if the alignrnent is not exact, the tabs 121 tend to push the closure 2
and'or container 200 into alignment.
FIG 4 demonstrates the situation where no webs are between the tabs.
Wall 412 has dependin~ sl;irt ~10. Tabs 421a, 421b, etc. surround the base. It is
2() clear that. in both the initial installation and the operation of the tabs to produce a
tamper-evident feature. that the tamper-e-ident result is defeated if one or more
tabs inadvertently ne~; outward at any time prior to in~t~ tion, as is shown in
FIG 4. Such a "tab-out" condition may occur during shipment or during the
installation itself. As may be seen from FIG 4, the tab-out condition is
'5 e.~acerbated by the independence of movement of individual tabs 421k. In other
words. because the movement of one tab 421k is not connected in any way to the
movement of another. once a tab 4'1(k-l) has flexed outward, its neighboring
tabs 421(k-2) and 1211; do not influence its movement. In particular, the
neighboring tabs do not serve to pull the tab 121(k-1) back in line.
FIG 3 shows that. in addition to the inventive features discussed above, the
present invention also includes webs 123 placed between the tabs 121. The webs
123 are advantageously present just near the base of the tabs 121, in particular, at
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the folded joints where the tabs 121 connect with the pilfer ring 125. However,
the webs 123 may extend even as far as the tabs 121 themselves. Generally, the
webs are made of a similar material as the closure, but their thickness is generally
less so as to not inhibit the tabs' inward movement. These webs prevent the
outward flexing of the tabs 121 by connecting the movement of one tab 121k
with the movement of its neighboring tabs 121(k-1) and 121(k+1). In this way,
the webs 123 serve to keep the tabs 121 from flexing outward by providing
tension against outward movements in which the average distance between points
on adjacent tabs 121 becomes relatively large. The webs 123 do not, however,
prevent the tabs 121 from flexing inward because the inward flex tends to
decrease the distance between the tabs 121. That is, the webs 123 are useful forpreventing the tab-oul condition~ but do not inhibit the effectiveness of the tabs
121 in providing a tamper-evident feature.
The -eakened area 1~4 may include, for example, a circumferential cut in
I ~ a series of frangible connecting posts (not shown) which hold the pilfer ring 125
to the rest of the closure 2. The circumferential cut is made in the pilfer ring (or
above the pilfer ring). which cut can be such that few of the connecting posts
remain. or most of the connecting posts survive the cutting, as desired. As the
present invention includes a pilfer ring 125 with tabs 121 and webs 123, the
'0 volume of the closure 2 below the weakened area 124 is relatively heavy. As
such. the frangible connecting posts. in this example, may need to be
manufactured in an especially strong manner to ensure that the pilfer ring does
not break away Aurin installation. It has been found th~t a preferable width and
thickness of such a connecting post lies in the range of .010 to .025 in. The
preferred materials are polyolefins such as polystyrene or polypropylene.
From the foregoing. it will be appreciated that an improved tamper-evident
closure is provided by the present invention. While a certain embodiment of the
present invention has been shown and described herein, there is no intent to limit
the invention by this description. The invention extends to all modifications and
alternate constructions falling within the spirit and scope of the appended claims.
