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Description  |
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The invention relates to sterile packaging of a liquid, and more
particularly to packaging assemblies allowing a liquid to be dispensed in
drops.
A typical case is that of tamperproof and sterile packaging for eye drops,
where the packaging assembly should permit easy dispensing of liquid in
the form of drops, in particular in the form of regular drops without any
jet.
This problem is well known to persons skilled in the art, and numerous
solutions have already been proposed.
A first type of proposed solution consists of techniques for manufacturing
packaging assemblies of the type referred to in the art as "bottle packs".
One such technique is known, for example, in U.S. Pat. Nos. 3,919,374 and
4,176,153.
The technique begins by extruding a preform, and then a bottle is blown
after closure; thereafter the (as yet unfinished) bottle made in this way
is filled, generally by means of a needle, and finally it is sealed (with
this final operation being performed by means of an additional top mould).
This technique is completely satisfactory for obtaining packaging
assemblies which are sterile, either with or without tamperproofing.
However, it is not suitable for obtaining satisfactory dispensing in the
form of drops.
For this application, a capsule or cap is used having an inside central
perforating pin. The hole formed in this way in the body of the packaging
assembly does not permit drops to be formed regularly (with drop
formatting depending to a large extent on the pressure exerted by the user
of the packaging assembly), and in addition the liquid jet is disordered.
In a variant, it has been proposed to replace the capsule-and-pin system by
a tear-off closure head (see, for example U.S. Pat. No. 4,378,891).
However, the orifice obtained necessarily has a relatively large diameter
(otherwise there would be a danger of the outlet channel being blocked).
The flow rate is therefore very irregular as before, and the jet is
relatively disordered.
Another type of proposed solution consists in using a prefabricated
subassembly constituting an enpiece and a stopper.
The advantage lies in the accuracy with which the subassembly can be
manufactured in advance by injection.
French patent number 2,511,973 shows several solutions of this type.
Such packaging assemblies are made by starting with a conventional bottle
blowing operation followed by filling, the end-piece and stopper
subassembly is then put into place, and the procedure is finished by
sealing the top portion, thereby simultaneously fixing the subassembly in
place (in a manner analogous to hot forming).
Sometimes sealing applies only to the bottom portion of the end-piece and
stopper subassembly (eg. see FIGS. 9 to 11 of French patent number
2,511,973), which has the disadvantage that it is then possible for the
stopper to be opened and to be closed. Sealing may alternatively apply to
the entire end-piece and stopper subassembly by ensuring that a kind of
cocoon is provided around the entire subassembly, thereby avoiding the
above-mentioned disadvantage (eg. see FIGS. 25 and 26 of French patent
number 2,511,973).
Such techniques making use of prefabricated subassemblies nevertheless
remain expensive (two injected parts need to be made separately and then
assembled, while always ensuring the required levels of cleanliness are
maintained).
Another important disadvantage lies in the imperfect sealing obtained.
As already mentioned above, if the end-piece and its stopper are directly
accessible, then there is a danger that the substance will no longer be
sterile after the packaging assembly has been stored. This arises, in
particular, because of the danger of the parts of the subassembly becoming
unscrewed while being conveyed (in a vibrating bowl) and/or while they are
being put into place. If a cocoon is provided, it must constitute a
tear-off closure head which means that a line of weakness needs to be
provided so that a patient can open the bottle, in other words a
connection is provided which is partially perforated. This always results
in a risk of leakage to a greater or lesser extent.
Further, it is well known that the technique of hot forming is difficult to
master (eg. variations in the formed substance can spoil forming). As a
result there is not only a further risk of leakage, but there is also a
risk that the product does not remain sterile (and unfortunately this is
not always visible from the outside).
All in all, these techniques using prefabricated subassemblies are
expensive and not very satisfactory either for sealing or for sterility.
Analogous techniques of an add-on stopper may also be mentioned (see U.S.
Pat. No. 4,226,334 and PCT application number WO 85/00 340, for example)
and the same disadvantages as mentioned above apply.
A third type of proposed solution consists in forming a channel of very
small diameter in the head of the packaging assembly (in which case
persons skilled in the art use the term "microchannel" since the diameters
involved are about one tenth of a millimeter to about three tenths of a
millimeter).
U.S. Pat. No. 4,584,823 illustrates a solution of this type.
A very fine needle is then used for making the microchannel.
In order to manufacture packaging assemblies of this type, the procedure
begins, as before, with a bottle-blowing operation and a filling operation
using a mandrel which is counted in a vertical axis drum. Thereafter the
mandrel is raised and the drum is located so as to bring the needle and
its support into alignment with the partially formed main body. The needle
is then put into place in a waiting intermediate mould and the mould is
then closed in order to allow the process to continue, ie. in order to
from a dispensing end-piece.
More recently, proposals have been made to improve this technique by
providing two intermediate moulds (with the assembly then being completely
closed by means of the third mould).
Nevertheless, this technique remains very difficult to perform, in
particular because of the fragility of the needle. The needle may break or
it may bend (if it breaks there is no hole, and if it bends there is a
danger of leakage). This means that the needle must be monitored on a
permanent basis in order to verify its condition, since it is difficult to
verify that a hole is indeed present and/or that sealing is satisfactory.
Finally, mention may be made of other techniques which are more remote but
which serve to illustrate the wide variety of possible solutions: these
techniques are described in PCT application number WO 86/00 598, British
patent number 2,053,866, German patent number 1,813,047, and U.S. Pat.
Nos. 2,893,613 and 2,324,237.
The principal object of the present invention is to provide a sterile
packaging assembly avoiding the above disadvantages and, more
particularly, making it possible to obtain regular drop formation without
forming a jet.
Another object is to produce a packaging assembly whose structure makes it
possible to avoid any risk of a sealing defect which could spoil
sterility.
Another object of the invention is to provide a packaging assembly which is
easy to use by a patient, even when the patient is an elderly person.
Another object of the invention is to provide a packaging assembly which is
simple in structure, and to implement an associated manufacturing method
which is simple and advantageous with respect to production costs.
More particularly, the present invention provides a sterile packaging
assembly for dispensing a liquid in drops, characterized by the fact that
it comprises a main body of plastic material, having a top portion with a
dispensing orifice and an outside thread for receiving a screw cap, and
containing a flow rate restriction system for controlling drop formation,
said system being positioned substantially on the axis of said main body
and being held in position by a constricted portion of the top portion of
said main body.
Preferably, the top portion extends beyond the flow rate restriction
system, via the dispensing portion which is surmounted by a closure head
that can be torn off in order to define a dispensing orifice on first
utilization of said packaging assembly.
According to a particular embodiment, the flow rate restriction system is a
small capillary tube whose central channel is delimited by two end facets.
In this case, the capillary tube may be cylindrical with a circular
cross-section, otherwise it may be cylindrical with a figure eight
cross-section. This is advantageous, insofar as capillary tubes are cheap
and available in long lengths, thereby making it easy to automate
manufacture. Suitably, the top facet of the capillary tube is inclined
relative to the axis of the central channel; the jet of the liquid can
thus be diverted towards the wall of the main body so that the jet broken
in this way is more easily transformed into a drop (a non-inclined facet
could run the risk of providing a small jet that did not form a drop).
Preferably, the top portion of the main body has a cylindrical bore beyond
the top facet of the capillary tube, the bore being wider than the
capillary tube in order to improve control of the size of liquid drops
during utilization of said packaging assembly.
Advantageously, in this case, the dispensing portion of the main body is
connected to the closure head beyond a rounded top shoulder terminating
the cylindrical bore by means of an annular zone constituting a rim
conferring a degree of elastic deformation in an axial direction to the
main body; in particular, the rim-forming annular zone is connected to the
closure head via necking making it possible to seal the main body by
applying axial pressure after said closure head has been torn off.
It is also advantageous for the top portion of the main body to be
terminated by a relatively narrow elongate neck constituting the
dispensing portion and is surmounted by a closure head which is wider than
said elongate neck; in particular, the closure head may have an outside
surface with outside teeth, said teeth serving to co-operate with
corresponding inside teeth of the screw cap in order to enable said
closure head to be detached by unscrewing said cap (for example, the
associated teeth of the closure head and of the screw cap may be in the
form of axial fluting).
Also advantageously, the packaging assembly of the invention it includes
snap-fastening means between the screw cap and the closure head, thereby
enabling said closure head to be retained in said cap after it has been
torn off by unscrewing the cap.
For example, the snap-fastening means may be essentially constituted by
radial fins surmounting the closure head with radial outside edges thereof
forming lugs which co-operate with an annular rim provided on the inside
surface of the screw cap; in particular, it is possible to provide two
radial fins situated in the join plane of the mould used for making the
main body.
In the first embodiment, the screw cap is unitary, and has, at the lower
end, a flexible thread which can move aside upon fitting by pressure, when
the said assembly is being put together, in contact with the outer
threading of the upper part of the main body.
In another embodiment, the screw cap is made of two parts which are fixed
together by axial snap-fastening, said parts comprising a main part with
an inside thread for screwing normally onto the top portion of the main
body when said assembly is being put together, and a second part
constituting a closure cap, with said second part having the toothed
portion which co-operates with the outside teeth on the closure head, and
a rotary drive connection being provided between said parts of said screw
cap.
Advantageously, in this case, the beyond part forming the closure cap has a
cylindrical sleeve penetrating into the main part of the cap, said sleeve
having inside teeth for co-operating with the closure head and having
outside teeth for co-operating with said main part; in particular, the
associated teeth are in the form of axial fluting, said fluting further
being such that the closure cap connects with the closure head prior to
connecting with the main portion of the cap.
It is also advantageous, for either embodiment, for the screw cap to have a
lower tamperproofing ring which is snap-fastened over the main body when
said assembly is put together, the said tamperproofing ring being toothed
internally in order to co-operate with the outer thread of the main body,
both the upper and lower connections by associated teeth to said screw cap
being homothetic in order to prevent any twisting of the closure head when
the said assembly is being put together, the lower connection additionally
providing for a centering of the said screw cap allowing the upper
connection to be positioned without risk of twisting of the said closure
head.
In another variant, the flow rate restriction system is a small capillary
tube whose central channel is delimited by two end facets, and whose lower
end is capped by a filter which is held in position by the constricted
portion of the top portion of the main body, the mesh of said filter being
chosen with respect to the desired degree of flow rate restriction.
Advantageously, in this case, the edge of the filter capping the capillary
tube is wedged between the said tube and the constricted portion of the
upper part of the main body. Also preferably, the capillary tube is
cylindrical and is circular in cross-section, and/or the top facet of the
capillary tube is inclined relative to the axis of the central channel.
In another variant, the flow rate restriction system includes at least one
porous tube bent into a horseshoe shape, with the two ends thereof being
disposed side-by-side and parallel to the axis of the main body and being
held in position by the constricted portion of the top portion of said
main body.
In yet another variant, the flow rate restriction system is a porous
cylindrical block disposed coaxially with the main body and held in
position by the constricted portion of the top portion of said main body,
the entire outside surface of said block being embedded in said
constricted portion; in particular, the porous cylindrical block is
preferably made of sintered polypropylene or polyethylene.
In yet another variant, the flow rate restriction system is a
longitudinally fluted cylindrical core or is made in the form of a porous
tube having a central channel, said system being disposed coaxially with
the main body and having its working side surface embedded in a filter
which is held in position by the constricted portion of the top portion of
the main body by being crimped between said constricted portion and the
fluted cylindrical core at each of the ends of the core, with the mesh
size of the filter being selected as a function of the desired degree of
flow rate restriction.
It is then advantageous for the constricted portion of the top portion of
the main body to have a central deformation level with the bottom end of
the fluted cylindrical core, thereby both holding said core in place and
defining two axial passages for conveying liquid to the working side
surface embedded in the filter. In particular, the filter may be wound
through slightly more than one turn around the fluted cylindrical core in
order to constitute an axial overlap layer; or else the filter may be made
up of two sheets whose opposite edges are interconnected, with the two
longitudinal lips being folded down.
It is also advantageous in the above-mentioned variant for the top portion
of the main body to have a cylindrical bore beyond the top end of the flow
rate restriction system, said bore being of greater width for the purpose
of improving control of the size of liquid drops during utilization of
said assembly.
Also preferably, the dispensing portion of the main body may be connected
to the closure head beyond a rounded top shoulder by means of a conically
flared annular zone. Advantageously, the top portion of the main body is
terminated by a dispensing end-piece which is surmounted by a hat-shaped
closure head which is wider than said end-piece; in particular, the
closure head has an outside surface with outside teeth for the purpose of
co-operating with corresponding inside teeth of the screw cap in order to
cause said closure head to be detached when said cap is unscrewed, with
the associated teeth being in the form of axial fluting.
Also preferably, the packaging assembly includes snap-fastening means
between the screw cap and the closure head, thereby enabling said closure
head to be retained in said cap after the head has been torn off by
unscrewing the cap; for example, the snap-fastening means is essentially
constituted by a spike in the form of an arrowhead surmounting the closure
head and suitable for co-operating with transverse lugs or a transverse
web in the screw cap.
Advantageously, the screw cap is unitary, and has, at the lower end, a
flexible thread, which can move out of the way on coming into contact with
the outside thread of the top portion of the main body while the assembly
is being put together by applying axial force; in particular, the screw
cap has a bottom tamperproofing ring which snap-fastens onto the main body
when the assembly is put together, the said tamperproofing ring having
internal teeth in order to cooperate with a corresponding outer teeth of
the said main body, both the upper and lower connections by associated
toothings to the said screw cap being homothetic in order to prevent any
twisting of the closure head when the said assembly is being put together,
the lower connection additionally providing for a centering of the said
screw cap allowing the upper connection to be positioned without risk of
twisting of the said closure head.
The invention also provides a method of manufacturing a plastic sterile
packaging assembly of the above type, the method being characterized by
the fact that it comprises the following stages:
a bottom portion of a main body is made by blowing in a main mould, said
bottom portion being intended to contain the liquid to be dispensed, after
which said main body is filled;
a flow rate restriction system is positioned substantially on the axis of
the main body by temporary support means;
the flow rate restriction system is held in place in a mould head which
clamps a portion of the main body onto said system on being closed.
According to another advantageous variant of the manufacturing method,
after the stage of positioning of the flow rate restriction system, the
following successive steps are additionally carried out:
a closure head is made in a sealing mould in order to terminate the main
body; and
a screw cap is put into place, thereby coupling the closure head in
rotation with said cap.
Other characteristics and advantages of the invention appear more clearly
in the light of the following description of various particular
embodiments, made with reference to the accompanying drawings, in which:
FIG. 1 is an axial section through a sterile packaging assembly in
accordance with the invention, in which the flow rate restriction system
is a small cylindrical capillary tube, and the screw cap is outlined, in
this case, in dot-dashed lines;
FIG. 2 shows a variant of the above assembly with a cylindrical bore being
provided above the capillary tube, thereby improving liquid drop size
control during use of said assembly;
FIG. 3 shows another variant in which the cross-section of the capillary
tube has a figure eight shape as can be seen in FIG. 4, which also
specifies section line III--III of FIG. 3 in greater detail;
FIGS. 5 and 6 show the gripping mandrel used in this case for installing
the figure eight section capillary tube;
FIG. 7 shows another variant in which the closure head has outside teeth,
with the screw cap being in two parts in this case;
FIG. 8 is a section on VIII--VIII of FIG. 7 showing the two rotary
connections via axial fluting;
FIG. 9 shows a variant of the above assembly in which the screw cap is
unitary, in which case it is put into place by applying axial force (the
cap has, at end, a flexible thread which moves out of the way while the
force is being applied).
FIG. 10 is a section on X--X of FIG. 9 showing the rotary connection via
axial fluting;
FIGS. 11a and 11b are diagrammatic sections showing the method of
manufacturing an assembly of the above type, with FIG. 11a corresponding
to preliminary blowing and filling operations and FIG. 11b corresponding
to subsequent operations of installing the capillary tube and final
sealing;
FIGS. 12 to 14 are sections through other variants in which the flow rate
restriction systems are respectively constituted by: a capillary tube
whose bottom end is capped by a filter; a porous tube folded into a
horseshoe shape; and a porous cylindrical block;
FIG. 15 is a section through another variant in which the flow rate
restriction system is a fluted cylindrical core whose working surface is
embedded in a filter (with the main body having a central deformation at
the bottom end of the embedded core, as can be seen more clearly by
referring also to the side view in section of FIG. 16);
FIGS. 17 to 20 are sections respectively on XVII--XVII, XVIII--XVIII,
XIX--XIX, and XX--XX of FIG. 15 for facilitating understanding of the
special shape of the body of the assembly;
FIGS. 21 and 22 are sections showing how the fluted core is covered by a
filter, respectively in the case of a single overlap and in the case of
two folded-down lips; and
FIG. 23 is a diagrammatic view of an apparatus which makes it easy to cut
and grasp lengths of capillary tube.
FIG. 1 shows a sterile packaging assembly 100 in accordance with the
invention for dispensing a liquid in drops. The packaging assembly 100
comprises a main body 101 of plastic material whose bottom portion 102
constitutes a bottle portion per se for receiving the liquid to be
dispensed, and whose top portion 103 has an outside thread for receiving a
screw cap 104.
In accordance with an essential aspect of the invention, the top part of
103 of the main body 101 has an internal flow rate restriction system 105
for controlling drop formation, said system being disposed substantially
on the axis on the main body 101 and being held in position by a
constricted portion 106 of the top portion 103 of said main body.
It is particularly advantageous for the top portion 103 to extend beyond
the flow rate restriction system 105 via a dispensing portion covered by a
closure head 110 in the form of a flat disc which can be torn off to
define a dispensing orifice 111 on the first occasion that said packaging
assembly, 100 is used.
The flow rate restriction system is constituted in this case by a small
capillary tube 105 whose central channel 107 is delimited by two end
facets 108 and 109. In this case, the capillary tube 105 is cylindrical
and is circular in cross-section, however this is merely by way of
example, as shown below. Such an embodiment is particularly advantageous
in that capillary tubes are cheap and are available in long lengths,
thereby making it easy to automate manufacture, as described below.
As can be seen in FIG. 1, the top facet 108 of the capillary tube 105 is
inclined relative to the axis of the central channel 107 (the bottom facet
109 is also inclined in this case, but that is merely the consequence of a
simplification to the way in which the small capillary tube is
manufactured). As a result, the jet of liquid can thus be diverted towards
the wall of the main body 101 so that the jet which is broken down in this
way transforms itself more easily into a drop.
The closure head 110 is connected to the dispensing portion of the main
body 101 via an annular zone constituting a rim 112, this improving the
geometry at the level of the dispensing orifice 111.
The flattened closure head 110 can be easily detached manually by twisting,
after unscrewing the cap 104 protecting the said closure head. It is also
possible to provide a rotational connection between the closure head 110
and the screw cap 104 when the packaging assembly is being put together
(for example by gluing or welding at the level of the opposite surface,
after positioning of the screw cap), thereby making it possible to entrain
the closure head 110 when the cap 104 is unscrewed, thus tearing the
annular zone 112 and releasing a central orifice 111 for dispensing
liquid.
Dot-dashed lines diagrammatically indicate the presence of moulds used in
the manufacture of the packaging assembly 100. It can thus be seen that
there is a main mould M1, a capillary tube holding mould M2, and a sealing
mould M3. Typical stages in the manufacturing method are described in
greater detail below with reference to FIGS. 11a and 11b.
However, the major advantages provided by such a disposition in accordance
with the invention can already be seen: the small capillary tube 105 makes
it easy to obtain regular drop formation without a jet; and the tear-off
head 110 ensures that the system remains sterile and sealed. Further, the
capillary tube is cheap (it is possible to use long extruded capillary
tubes of the type used in aerosol manufacture, for example). By way of
comparison, such a small capillary tube is about 30 times cheaper than an
injected end-piece and stopper subassembly as used in certain prior art
techniques mentioned above.
Drop formation is completely controlled. The flow rate restriction system
constituted in this case by the capillary tube 105 is particularly
effective in controlling the flow rate, given that it is easy to form a
microchannel 107 in such a tube. Drop size is essentially a function of
the geometrical shape of the dispensing end, and overall results are very
satisfactory.
It should be observed that the axial fixing of the small capillary tube 105
is not critical in any way for obtaining satisfactory drop-forming
qualities. This facilitates manufacture, particularly when the capillary
tube is held in position by the constricted portion 106 (with such fixing
being equivalent, in fact, to welding, particularly if materials of the
same nature are used, such as polyethylene).
However, it should be observed that, when using a packaging assembly
exactly as shown in FIG. 1, the quality of the result is not optimal with
respect to drop size, and this is essentially due to the special shape of
the dispensing portion of the main body 101 beyond the capillary tube 105.
The purpose of the variant shown in FIG. 2 is specifically to overcome this
drawback. The packaging assembly 200 has a large number of features in
common with the packaging assembly 100 as described above, and such common
features are therefore given the same references as above, plus one
hundred.
The essential difference compared with the previous variant lies in the
shape of the dispensing portion of the main body 201. It can be seen that
the top portion 203 of the main body 201 has a cylindrical bore 213 beyond
the top facet 208 of the capillary tube 205 which is wider than the
outside diameter of the capillary tube, thereby quite substantially
improving control of the size of liquid drops when said packaging assembly
is used. Further precautions are taken with geometrical shape at the
dispensing orifice 211. In this case the cylindrical bore 213 is
terminated by an outwardly directed annular rim 214, and the weak annular
zone 212 interconnecting the tear-off head 210 and the main body 201 lies
on the outside of the rim.
The improved geometrical shape provides a quite substantial improvement in
drop accuracy, and this constitutes a considerable advantage even though
the size of the drop is bigger than before, thus leading to a quantity of
liquid being dispensed which may be greater than the quantity strictly
necessary. It should also be observed that the formation of the
cylindrical bore 213 and the top annular rim 214 naturally makes
manufacture somewhat more complicated (it becomes necessary to provide a
suitably shaped grasping system, as described below).
The variant shown in FIG. 3 makes it possible to remedy the drop size
problem when very high accuracy is desired in this respect.
The packaging assembly 300 comprises, as before, a main body 301, with a
top portion 303 having an outside thread, said top portion being extended
by a constricted portion 306 for holding a flow rate restriction system
305 in position. The essential difference compared with the
above-described embodiment lies in the special shape of the flow rate
restriction system 305 which is constituted in this case by a small
cylindrical capillary tube having a figure eight crosssection (the section
of FIG. 4 shows this particular sectional shape more clearly). This
section makes it possible to take advantage simultaneously of having both
a small and a large outside diameter. The small diameter makes it possible
to obtain a drop which is small in size, while the large diameter in the
other direction makes it possible to retain sufficient substance for good
mechanical behavior and ease of grasping during manufacture. Further, as
above, it is advantageous to cause the top facet 308 of the capillary tube
305 to be inclined relative to the axis of its central channel 307.
Further as for the variant shown in FIG. 2, there is a cylindrical bore
313 beyond the capillary tube 305 which is terminated by an annular rim
314 at the dispensing orifice 311.
FIGS. 5 and 6 show the bottom end of an end-piece 315 serving as a grasping
system when using a capillary tube of the same type as above-described
tube 305. The end-piece 315 has an annular shoulder 316 whose function is
to define a smaller diameter cylindrical portion 316 during moulding of
the annular rim 314 for the propose of defining a bottom cylindrical bore
313, and finally two lugs 316 for holding a length of capillary tube 305
by means of its small diameter portion.
Naturally, in some cases, it may be advantageous to provide an outside
thread on the portion 306 of the main body 301 for the purpose of screwing
on a stopper after the head 310 has been removed. FIG. 4 also makes it
possible to understand the special shape of the portion 306 of the main
body which results from using a capillary tube 305 having a figure eight
cross-section. It should also be observed that the section of FIG. 3
comprises a left half section in a plane perpendicular to the opening
plane of the mould M2, whereas the right half-section corresponds to a
section in the opening plane of said mould.
FIGS. 7 to 10 show variants of the invention in which the top portion of
the main body is terminated by a relatively narrow elongate neck
constituting the dispensing portion which is surmounted by a closure head
which is wider than said elongate neck, said closure head also having an
outside surface with outside teeth for the purpose of co-operating with
corresponding inside teeth on the screw cap in order to detach said
closure head by unscrewing said cap.
It should be observed that in prior techniques using a tear-off head, the
head has been torn off by hand, such that the packaging assembly could not
be reclosed, thus requiring the use of a separate stopper, preassembled or
otherwise. This gives rise to a succession of operations that can be
difficult for some patients who must, in succession: open the cap; tear
off the head; remove the head; and then reclose the assembly. Persons
skilled in the art then encounter a well-known problem: if the tear-off
head is small in diameter, then it is difficult to handle; whereas if it
is large in diameter, then although it is easier to handle, a preassembled
separated cap or stopper is required.
Thus, in accordance with an advantageous embodiment of the invention, a
screw cap is provided which performs two functions ie. not only does it
provide initial opening by tearing off the head, it also allows the
packaging assembly to be reclosed. However, it should be observed that an
additional difficulty needs to be overcome in this case, namely to ensure
that under no circumstances can the head be torn off prior to the screw
cap being unscrewed on the first occasion that the packaging assembly is
used. It is therefore necessary to ensure that the forces which may be
communicated from the screw cap to the tear-off head when the screw cap is
being put into place are kept small, and in particular that twisting
forces are kept small.
The packaging assembly 400 shown in FIGS. 7 and 8 includes portions which
are common with the assemblies described above, and in order to avoid
overloading the description, these portions are given corresponding
reference numerals in the four hundreds.
The dispensing portion of the main body 401 is connected to the closure
head 410 beyond a rounded top shoulder 414 which terminates the
cylindrical bore 413 by means of an annular zone constituting a rim 412
and which imparts a degree of elastic deformation in an axial direction to
the main body 401. The annular zone forming the rim 412 is also connected
to the closure head 410 by necking 412 which makes it possible to seal the
main body 401 by applying axial pressure after said closure head has been
torn off. In addition, the top portion 403 of the main body 401 terminates
in the form of a relatively narrow elongate neck constituting the
dispensing portion and closed by a closure head 410 which is wider than
said elongate neck, with said closure head 410 having an outside surface
419 with outside teeth for the purpose of co-operating with corresponding
inside teeth 421 on the screw cap 404 so as to ensure that said closure
head is detached when the screw cap is unscrewed. The cooperating teeth of
the closure head 410 and of the screw cap 404 are advantageously in the
form of axial fluting.
In this case, the screw cap 404 comprises two parts 417 and 418 which are
fastened together by axial snap-fastening. A main part 417 has an inside
thread for being screwed in the normal manner onto the top portion 403 of
the main body 401 when the assembly is being put together, and a second
part 418 constituting a closure cape, said second part having the toothed
portion which co-operates with the outside teeth on the closure head 410.
Naturally, a rotary drive connection must be provided in this case between
the two portions of the screw cap. Thus, the second part constituting the
closure cap 418 has a cylindrical sleeve 418 which penetrates into the
main part 417 of the cap 404, said sleeve having inside teeth for
co-operating with the closure head 410 (axial fluting 422 on the sleeve
418 and corresponding axial fluting 420 on the main part 417). It should
be observed that lugs 423 are provided on the inside of the main part 417
in order to provide axial snap-fastening with a corresponding groove in
the second part constituting the closure cap 418.
It is also advantageous to provide snap-fastening means between the screw
cap 404 and the closure head 410 for retaining said closure head in the
cap after the head has been torn off by the cap being unscrewed. In this
case, the snap-fastening means is essentially constituted by radial fins
424 on top of the closure head 410 with the radially outer edges thereof
constituting lugs which co-operate with an annular rim 425 provided on the
inside surface of the screw cap 404. It is preferable to provide two
radial fins 424 situated in the join plane of the mould used for making
the main body 401. In this case it is preferable to ensure that the
associated teeth are in the form of axial fluting organized in such a
manner that the connection between the closure cap 418 and the closure
head 410 takes place prior to the connection between said closure cap and
the main part 417 of the screw cap 404. It may also be observed that the
main part 417 of the screw cap 404 has a tamperproofing ring 426 at its
bottom end which has a toothed inside surface (preferably with axial
fluting not shown here), with connection taking place via points 426',
said ring snap-fastening by means of a circular groove 427 therein over a
swelling 428 of the main body 401 when said assembly is put together, in
order to cooperate with a corresponding outer toothing of the main body
401 when the packaging assembly is put together. In this case it is
expedient to ensure that the two upper and lower connections by teeth
associated with the screw cap 404 are corresponding in order to avoid any
twisting of the closure head 410 when the packaging assembly is being put
together, the lower connection additionally affording a centering of the
screw cap 404 permitting correct positioning of the upper connection
without risk of twisting of the said closure head 410.
Once the main body 401 has been made together with its capillary tube 405
and its tear-off closure head 410 with outside teeth, the screw cap 404
should be put into place. This is begun by putting the main part 417 into
place by screwing it onto the main body 401 until the tamperproofing ring
426 snap-fastens, after which the part 418 forming the closure cap is put
into place solely by applying twist to the closure head 410. Once the
closure cap 418 has snap-fastened onto the main part 417, then said cap is
certain to have snap-fastened properly to the closure head 410 via the
radial fins thereof, with the elasticity in the axial direction conferred
by the interconnecting rim 412 preserving flexibility of the system. In
addition to ensuring that the assembly is tamperproof, it should be
observed that this disposition makes it possible to centre the closure
head 410 axially, with centering taking place progressively, initially by
means of the closure cap 418 engaging the closure head 410 axially
(through an angle corresponding in this case to 1/12th of a turn), and
subsequently by the main part 417 on the preceding subassembly (in which
case the angle is about 1/48th of a turn), thereby ensuring that no twist
forces are transmitted to the closure head 410.
A practical advantage of making the screw cap 404 in two parts needs to be
underlined, namely: the two parts can be made in different colours,
thereby enabling a packaging assembly to be readily identified by a
patient. Handling can be further facilitated by providing longitudinal
ribs 429 on the outside surface of the main part 417 of the screw cap 404.
It should be observed that after the cap 404 has been unscrewed for the
first time, and the head 410 has been separated, the necking 421 of said
head (which head is retained inside the screw cap) serves during
subsequent closure to reseal the packaging assembly by bearing against the
annular rim 414.
FIGS. 9 and 10 show a variant of the abovedescribed embodiment, with the
screw cap in this variant no longer comprising two parts, but being
constituted by a single part.
In order to avoid overloading the | | |
