[0001] This invention is directed to a closure combination comprising a closure plug and
a tamper evident, closure overseal for shipping containers; such as drums.
BACKGROUND OF THE INVENTION
[0002] In today's global political climate the security of drummed products is coming under
ever closer scrutiny. This, coupled with the need for normal tamper vigilance, is
driving a trend toward the increased use of effective tamper indicating seals on all
types of shipping containers. It has long been the practice to apply overseals of
one kind or another with special hand and power tools which were able to crimp a metal
portion of the overseal tightly around an upstanding opening neck designed to receive
the seal. This type of overseal is rather costly as are tools for their application.
Moreover, the application step itself is quite labour intensive and relatively inefficient.
Consequently a number of hand applied overseals have come forth which to a certain
degree obviate the above-mentioned application tools. These hand-applied overseals
are for the most part easily snapped onto the container opening neck and usually almost
as easily snapped off. While these plastic snap-on overseals serve to dress up a container
such as a 55 gallon drum, giving the closure area a finished appearance and some added
degree of cleanliness, there is still much to be desired in terms of drum security.
To be effective such drum closure overseals need to meet a number of rather demanding
criteria. Obviously the hand application has to be simple and relatively effortless
to satisfy normal filling line speeds. Once the drum is shipped, of paramount importance
is the ability of the overseal to guard against unauthorized access to the drum contents.
This means that the overseal cannot be physically removed without destroying same
or making such unauthorized access clearly noticeable and such that the overseal cannot
be reapplied in unaltered form to the drum closure. In this regard, plastic, manually-applied
overseals currently in general use for both steel and plastic drums are, for the most
part, easily pried off in an undetected manner particularly when in a warmed state.
In other words "easy-on easy-off".
[0003] Also of importance is the ability of the overseal to resist inadvertent damage during
handling and shipment. Commonly employed tamper detection devices such as frangible
locking rings, shrink bands and the like found on consumer packages are not at all
suited for use on 55 gallon drums. One can easily see that any inadvertent or accidental
damage to the tamper resistant overseal immediately raises the question, has the drum
security been breached or compromised in some way or is this simply damage to be expected
resulting from normal handling? This aspect dictates that any tamper detecting feature
be sufficiently robust to remove any question of doubt as to whether unauthorized
entry has in fact occurred.
[0004] A performance criteria also of major importance is the ease with which the overseal
can be removed from the underlying drum closure in an authorised manner such that
subsequent replacement of the overseal is not possible. Normally this requires destruction
of the overseal in some fashion to prevent reuse. In this regard the use of sharp
cutting or puncturing implements is undesirable due to the likelihood injury or of
accidental damage to the underlying closure. Thus, in addition to the overseal's robust
construction, hand removeability is yet another advantageous attribute.
PRIOR ART
[0005] Document
DE-A-36 37 644 discloses a closure plug and tamper evident overseal combination for shipping containers
(11), the closure plug (2) and the overseal (3) having hidden, complimentary, interlocking,
snap-fit features (7, 8, 10) and a frangible portion (9) to permit removal of the
overseal from the plug. The interlocking features comprise "On the under side of the
seal cap (3), there are integrally formed two half-shells (7), projecting into the
stopper cavity between the wrench attachments (5), which half-shells - when the seal
cap (3) is snapped on - engage with the help of arresting projections (8) - arranged
at their lower end - behind corresponding undercuts (10) in the lateral wall of the
stopper cavity, and that above the arresting projections (8), predetermined breaking
notches (9) are provided in the outer jacket of the half-shells (7)." [Col. 1 lines
13-22]. The undercut 10 is shown by Figs 1 and 2 to only to extend to either side
of wrench attachments (5). Also, the relative angular position of the plug and overseal
is critical for fitting the one to the other as the half-shells (7) could foul the
wrench attachments (5).
OBJECT OF INVENTION
[0006] It is an object of the present invention to provide a solution to the tamper-detection
problems of the closure plug and tamper evident overseal combination as described
in respect of document
DE-A-36 37 644.
STATEMENT OF INVENTION
[0007] According to the present invention, a closure plug and a tamper evident, closure
overseal combination for shipping containers, comprises a closure plug having a cylindrical,
cup-shaped body with axially-extending, wrench engaging lugs about the inner periphery
of the plug sidewall and a segmented, radially and circumferentially extending groove
formed in the sidewall and an overseal has having axially extending, resilient legs,
each having a radially-extending foot for hidden, complimentary, interlocking, snap-fit
engagement with the radial groove undercuts and a visible frangible portion to permit
removal of the overseal from the plug; wherein the inner, segmented locking groove
is formed by a radial undercut at the base of each lug, as defined in claim 1.
[0008] When it comes to removal in an authorized manner, manually tearing the visible frangible
portion of the overseal results in the interengagement of the interlocking features
being released and the overseal is easily removed. However, unlike the overseal of
document
DE-A-36 37 644, the overseal of the present invention is quite obviously destroyed and rendered
completely unusable for resealing.
[0009] The present invention also extends to closure plugs in accordance with the combination
of the present invention.
[0010] According to another, further embodiment of the present invention, the closure plug
has axially extending wrench engaging lugs equi-spaced about the inner periphery of
the plug sidewall and the space between lugs may be at least as great as the width
of the lugs.
[0011] The above and further features of the present invention are illustrated, by way of
example, the following description and drawings.
DRAWINGS
[0012]
Fig. 1 is a vertical cross sectional view of a closure combination in accordance with
a first embodiment of the present invention;
Fig. 2 is an enlarged fragmentary sectional view of the plug wrench engaging lug of
the closure plug of Fig. 1;
Fig. 3 is a top plan view of the closure plug of Fig. 1;
Fig. 4 is a vertical cross sectional view of the closure overseal of Fig. 1;
Fig. 5 is a bottom plan view of the overseal shown in Fig. 4;
SPECIFIC DESCRIPTION
[0013] In the embodiment shown by Figs 1 to 5, a wall 1 of a container, such as an industrial
size plastic drum, has an upstanding neck 2 defining an internally threaded opening
in the container wall. The neck 2 terminates at its upper end in an annular gasket
seat 3a surrounded by an upstanding collar 4. Immediately beneath the collar 4 is
a peripheral annular bead 5.
[0014] A cup shaped closure plug 6, having a bottom wall 7 and an externally threaded sidewall
8, is screwed into the neck 2. The plug has a circumferentially enlarged head 9 with
a gasket retaining groove 10 and resilient sealing gasket 11 on the undersurface thereof.
Looking at the top surface of the plug in Fig. 3, there are a series of four equally
spaced wrench engaging lugs 12 which are hollowed out as indicated at 13. Also, it
can be seen that the width of the lugs 12 is slightly less than the width of the gaps
14 therebetween. Each lug has two radially extending wrench engaging surfaces 15 and
a radially inwardly facing guide surface 16. The base of each lug 12, where it joins
the plug bottom wall 7, is radially undercut to form a locking groove 17 designed
to interlockingly engage the closure overseal in a manner described hereinafter.
[0015] The closure overseal 20 consists of an imperforate cap moulded of synthetic plastic
resin having a disc-like top wall 21 surrounded by a peripheral depending skirt 22.
A segmented collet depends from the central portion of the cap made up of a series
of axially elongated leg segments 23 clearly shown in Fig. 4. Each segment terminates
at its distal end in a radially outwardly projecting foot 24 having a bottom cam surface
25. A tear strip 26 is formed in the cap and is defined by a pair of score lines 27
extending diametrically across the top wall 21 so as to intersect the segmented collet
shown, for purposes of illustration, with three of the segments 23 on one side of
the tear strip 26 and three segments on the other side of the tear strip. As the score
lines 27 approach the cap skirt 22 they diverge outwardly at 28 and continue across
the skirt including the circumferentially enlarged portion 22a down to the skirt edge.
A tearing ear 29 extends outwardly from either end of the tear strip and is provided
with a raised outer edge bead 30 to facilitate gripping.
[0016] In practice the plug 6 is screwed into the upstanding neck 2 of a shipping container,
such as a blow moulded plastic drum, and tightened by a suitable plug wrench designed
to exert a force against the wrench engaging surfaces 15 of the lugs 12. Tightening
torque applied in this matter causes the gasket 11 to become compressed against the
neck gasket seat 3 providing a leak proof liquid seal. The overseal 20 is then placed
over the plug with the segmented collet generally axially aligned with the central
portion of the plug defined by the wrench engaging lugs. Simply pressing the overseal
by hand onto the plug causes the camming surfaces 25 on the segment feet 24 to deflect
the segments 23 radially inwardly upon forceful contact with the top of the wrench
engaging lugs 12. As the segment feet move axially along the lug guide surfaces 16,
the skirt free edge contacts the neck bead 5 causing the skirt enlargement 22a to
expand thereover. In fully seated position the segment feet 25 snap into the wrench
engaging lug grooves 17 expanding back out to their moulded position. This snap-fit
interlocking engagement permanently secures the overseal to the plug and, of course,
the plug to the container opening since the wrench engaging lugs are rendered inaccessible.
In fact, as seen in Fig. 1, the segmented collet itself is inaccessible to any kind
of pry off tool making unauthorized removal of the overseal extremely difficult, if
not impossible, without destroying the overseal or certainly leaving very clear evidence
of tampering. To assure the necessary security the arcuate grooves 17 extend laterally
and are disposed completely below the plug head top surface and open in an axial plane.
The design of the closure plug and overseal is such that the overseal will snap-fit
with the plug irrespective of their relative angular position. The overseal 20 is
an interference fit on the container neck bead 5.
[0017] To gain authorized access to the container contents one tearing ear 29 is grasped
aided by the raised bead 30 and pulled outwardly separating the tear strip 26 along
the score lines 28 and 27 from the rest of the cap. Removal of this top wall section
allows the segmented collet to collapse; releasing the segment feet 25 from the grooves
17. This release condition occurs when the tearing action reaches the far side 4 of
the top wall 21. At this point, the destroyed and released overseal simply lifts off
of the neck 2 still in one piece so that loose cap fragments do not become a problem.
Once the overseal is torn off, not only is there assurance against prior opening of
the container but in addition the plug and surrounding gasket seat remain dirt free
and uncontaminated.
[0018] Various other changes in or modifications of the closure combination of the present
are possible; for example the number and spacing of the collet segments could vary.
1. A closure plug and tamper evident, closure overseal combination for shipping containers
comprising:-
a cup-shaped closure plug (6) having:-
a plug sidewall (8),
axially-extending, wrench-engaging lugs (12) about the inner periphery of the plug
sidewall (8),
and
an inner, segmented locking groove (17),
wherein the closure plug (6) has a bottom wall (7);
and
an overseal (20) having:-
axially extending, resilient legs (23), each with a radially-extending foot (24) for
hidden, complementary, snap-fit, interlocking engagement with locking groove segments
(17), and
a visible frangible portion (26) to permit removal of the overseal from the plug;
characterised in that:-
the base of each lug (12), where it joins the plug bottom wall (7), is radially undercut
to form the locking groove segments (17).
2. A closure plug for the closure plug and tamper evident, closure overseal combination
of claim 1.
3. A closure plug as claimed in claim 2, wherein the lugs (12) extend axially and are
equi-spaced about the inner periphery of the plug sidewall (8) with the space between
lugs at least as great as the width of the lugs.
4. A closure plug as claimed in claim 2 or claim 3 and having four lugs (12).
1. Kombination aus Verschlussstopfen und (manipulationssicherem) Originalitätsverschluss
für Versandbehälter, umfassend:
einen topfförmigen Verschlussstopfen (6) mit:
einer Stopfenseitenwand (8),
axial verlaufende Schlüsseleingriffsansätze (12) um den inneren Umfang der Stopfenseitenwand
(8) herum,
und
eine innere segmentierte Verschlußausnehmung (17),
wobei der Verschlussstopfen (6) eine Bodenwand (7) aufweist;
und
eine Überdichtung (20) mit:
axial verlaufenden, elastischen Schenkeln (23), jeweils mit
einem radial verlaufenden Fuß (24) zum verdeckten, komplementären, ineinandergreifenden
Rasteingriff mit Verschlussausnehmungssegmenten (17),
und
ein sichtbarer zerbrechlicher Abschnitt (26), der eine Entfernung der Überdichtung
von dem Stopfen erlaubt;
dadurch gekennzeichnet, dass
das Unterteil jedes Ansatzes (12) dort, wo er an der Stopfenbodenwand (7) ansetzt,
radial unterschnitten ist, um die Verschlussausnehmungssegmente (17) zu bilden.
2. Verschlussstopfen für die Kombination aus Verschlussstopfen und Originalitätsverschluss
von Anspruch 1.
3. Verschlussstopfen nach Anspruch 2, wobei die Ansätze (12) axial verlaufen und in gleichen
Abständen um den inneren Umfang der Stopfenseitenwand (8) herum angeordnet sind, wobei
der Abstand zwischen Ansätzen zumindest so groß wie die Breite der Ansätze ist.
4. Verschlussstopfen nach Anspruch 2 oder 3 und vier Ansätze (12) aufweisend.
1. Combinaison de bouchon de fermeture et capsule de garantie de fermeture, inviolable,
pour conteneurs d'expédition, comprenant :
un bouchon de fermeture (6) en forme de coupelle, comportant :
une paroi latérale de bouchon (8),
des pattes d'engagement de clé (12) s'étendant axialement, autour de la périphérie
interne de la paroi latérale de bouchon (8),
et
une rainure de verrouillage segmentée interne (17) ;
le bouchon de fermeture (6) comportant une paroi inférieure (7) ;
et
une capsule de garantie (20) comportant :
des jambages élastiques (23) s'étendant axialement, chacun pourvu d'un pied (24) s'étendant
radialement pour un engagement par verrouillage réciproque, par encliquetage, complémentaire,
dissimulé, avec des segments de rainure de verrouillage (17),
et
une partie susceptible de rupture (26), visible, pour permettre d'enlever la capsule
de garantie du bouchon ;
caractérisée en ce que :
la base de chaque patte (12), à l'emplacement de sa jonction avec la paroi inférieure
de bouchon (7), est radialement découpée par en dessous pour former les segments de
rainure de verrouillage (17).
2. Bouchon de fermeture pour la combinaison de bouchon de fermeture et capsule de garantie
de fermeture, inviolable, selon la revendication 1.
3. Bouchon de fermeture selon la revendication 2, dans lequel les pattes (12) s'étendent
axialement et sont équidistantes autour de la périphérie interne de la paroi latérale
de bouchon (8), l'espace entre les pattes étant au moins aussi grand que la largeur
des pattes.
4. Bouchon de fermeture selon la revendication 2 ou la revendication 3 et comportant
quatre pattes (12).