Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to a mold and a method oF
molding an improved tamper indicating closure.
B~CKGROUND OF T~IE INVENTION
There presently exist numerous tamper indicating closures
for containers, bottles, etc. These closures come in various
materials for example, metals and plastics predominently~ Metal
closures however have the disadvantage of being expensive, and prone
to leaving sharp edges which can cut the user's fingers.
Some closures are adapted to allow for a portion thereof to
be left on the container after opening as an indication of tampering.
This is often accomplished by requiring the user to pull or strip
from the closure a band, typically situated between the threads of
the closure and the portion remaining on the container to allow the
unscrewing of the closure. Thusg two operations are required for
removal of the closure in addition to the discarding of the band. In
addition, experience has proven that the tamper proof evidence in
these closures many times will not remain on the neck of the bottle.
Other types of closures provide for a breakaway portion
which breaks from the closure during unscrewing thereby providing for
a single operation. This type of closure may come in a single piece
or a plurality of pieces~ Many of these closures are made of
inappropriate material, involve complicated design of the closure
and/or container cr involve complex molding techniques, limiting
their application.
Thus, it would be advantageous to have a simple but
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effective tamper proof closure which would indicate tampering once
opened, inhibit reuse of the container for bogus material, yet be
asthestically pleasing with straight walls and effective in resealing
d bottle. It would also be advantageous to have a closure which
could be readily molded and used on a bottle with a relatively simple
neck thus reducing the cost of the manufacturing of the bottle.
In this regardl typical molding techniques for closures
usually require that the cores be skepped or offset to facilitate
molding so as to get the closure off the core. Such molding does not
lend itself to the production of straight molded closures and
obviously requires involved complicated molding techniques.
In the molding of closures that do have straight sidewalls,
the molds usually require a collapsible core or a cam action cavity
to enable the removal of the closure therefrom, obviously complicated
and expensive.
A further consideration in closure design is the material
from which it is molded and the molding technique required. In many
cases whether strip molding is used depends upon the type of material
involved since it can result in excessive stretching of the closure.
Accordingly, there is a need for a means for molding a straight sided
closure which is relatively simple yet effective.
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Accordingly, it is an object of the invention to provide
for a means of molding a single piece tamper indicating closure
suited for various types of containers which is relatively simple in
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construction, operation and expense and which allows for the
fabrication of a closure which is asthetic in appearance being
straight walled with a breakaway skirt or portion thereon which will
normally remain on the container when the closure is removed so as to
indicate tampering.
A yet further object of the invention is to provide for a
means of molding a tamper indicating closure which is readily
removable from the core of the mold while allowing it to be made of a
variety of resins, and does not require a core which is collapsible
or a cam action cavity to remove the closureJ
The tamper indicating closure to be molded is formed in d
single piece, with or without a liner, and is provided with a
breakaway skirtO A flat crown or dome is provided and a sidewall
downwardly extending therefrom. A breakaway skirt is coupled to the
sidewall via a frangible connection comprising a serration or a
plurality of straps formed out of the sidewall and positioned between
the top of the breakaway skirt and the sidewall.
The inside wall of the breakaway skirt is molded so as to
be provided with a continuous circumferentially extending wedge
shaped ring. In one embodiment in this regard~ the wedge shaped ring
includes a plurality of locking lugs which are formed in such a
manner to assist in the screwing off of the closure from the core
once the mold or cavity is removed. In another embodiment, the core
of the mold is formed out of three parts to enable the stripping of
closure therefrom. Once the cavity is removed, the first part of the
core which forms the crown, sidewalls and threaded portion in
cooperation with the cavity is axially displaced with respect to the
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second part of the core which also forms a portion of the sidewall in
conjunction with the frangible portion and breakaway skirt.
Contemporaneously, a third part of the core, in the shape of a
sleeve, serves to assist in pushing the closure, particularly the
breakaway skirt thereof, off the second part of the core thereby
advantageously preventing undue strain on the frangible portion so as
to prevent its fracture.
Thereafter tlle closure is removed from the first part of
the core by unthreading.
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The above mentioned as well as other objects and advantages
of the present invention will become more apparent from the
description thereof which is to be taken in conjunction with the
accompanying drawings in which:
Figure l is a partially sectional view of the cavity and
core for a tamper indicating closure, incorporating the teachings of
the present invention;
Figure 2 is a substantially sectional view of the cavity
and the core with a tamper indicating closure formed therebetween,
Figure 3 is a partially sectional view of a second
embodiment showing a cavity and three piece core for a tamper
indicating closure, incorporating the teachings of the present
invention;
Figure 4 is a partially sectional exploded view of the
cavity and core shown in Figure 3;
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Figure 5 is a partially sectional view of the core with a
tamper proof closure formed thereon and the cavity removed from the
core;
Figure 6 is a partially sectional view of the parts of the
core in phantom and advanced to enable the stripping of the closure
thereFrom;
Figure 7 is a perspective view of another embodiment of the
core having 1ug notches thereon to ~orm lugs on the closure allowing
the screwing off of the closure in certain applications;
Figure 8 is a partial enlarged view of the notches on the
core shown in Figure 7; and
Figure 9 is an enlarged view of raised lugs on the core to
form notches on the closure allowing the screwing off of the closure
in certain applications.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Turning now to Figures 1 and 2, there is shown a means for
readily molding a tamper indicating closure 10, as shown in Figure 2.
With refPrence to Figure 1~ there is shown a mold or cavity
12 having an openiny 74 to allow the material (i.e., polypropylene,
polyethylene etc.) to be molded to enter the CdVity when it is placed
over a core 76 so as to form the closure 10 as described in the
immediately aforementioned application.
As shown in Figure 2, the outer surface of the core 76
compliments the internal surface of the closure, with the internal
surface of the cavity complimenting the external surface of the
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closureD Note that the point of widest diameter of ~he core at 78
forms an undercut Ineans and in conjunction with the cavity 72, a
point of reduced area therebetween on the closure 10, allowing
formation of the frangible portion between the breakaway portion 20
and sidewall 14. Variation of the width of this area allows for a
variation of the thickness of the frangible portion to a point where
the frangible portion would be formed just out of the vertical side
ribs thereby providing a serrated appearance around the closure 10.
Once the closure is formed on the core 76, the cavity 72 is
lifted off. The closure 10 is then merely turned off of the core.
As this occurs~ the angular upper surface of the wedge shaped
internal riny assists in allowing this without causing undue stress
on the frangible portion. Also the locking 1ugs 60 on the closure
10, at point 66 are practically flush with surface 5~ and ease the
closure gradually off the core with the thickness of surface 64
increasing gradually expanding the breakaway portion 20 until the
apex 58 of the ring and lugs 60 have passed the point of the widest
diameter of the core at 78. The diameter of the apex 58 is
sufficiently large so that it clears the threaded portion of the
core, and continued turning causes the closure to turn completely off
of the core. Accordingly, the closure 10 may be readily molded out
of a variety of materials and removed from the core of the mold
without the necessity of a complicated procedure or collapsible core,
or cam action cavity.
Also, as aforenoted, at point 78 during molding, the
sidewall 14 of the closure is the thinnest and by using the vertical
ribs in conjunction with a thin wall, readily allows for the
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formation of the serrated line without any complicated procedure or
molding.
Turning now to the embodiment shown in Figures 2-6, there
is shown a molding apparatus for a tamper proof closure.
Briefly, as can be seen in Figures 3, 5 and 6, the closure
110 has a dome or crown 112 which is circular in form with a flat
external surface. Extending downward from the crown is an annular
sidewall 114 on which is located a plurality of outwardly tapered
vertical ribs 116 which facilitate grasping the closure. Attached to
the sidewall 114, via several longitudinal straps or connectors 118
making up the frangible portion, is a breakaway skirt 120.
The sidewall 114 has located on its internal surface a
helical thread 122 which would correspond, in a mating like relation-
ship, to the thread on a container to which it is placed so as to
allow the closure to be screwed on and off. Below thread 122 is a
straight cylindrical portion 124 which continues to the bottom rim
126 of the wall.
The breakaway skirt 120 has smooth outer surface 128 and
two inner surfaces 130 and 132 forming a wedge shaped internal ring
134, The surface 130 as can be seen is formed of actually two
angling surfaces. Inner surface 130 and outer surface 128 form the
top 136 of the sklrt, while inner surface 132 and outer surfaçe 128
form the bottom 138 of the skirt.
Note that during the molding process the breakaway skirt
120 may have a circumference slightly larger than that of the
sidewall 114. If this occurs, the closure will however straighten
out when placed on the container.
The skirt 120 is connectecl at the lower end oF wall 114 by
several horizontal straps or connectors 1189 with the straps being
affixed to the breakaway skirt 1209 at 136. These straps are
arranged around the bottom portion of wall 114 and may be at equal
arc length to each other and seven or eight in number, although not
limited thereby. Note that the straps 118 may be formed out of a
select number of vertical ribs 116 if formed in an area where the
ribs extend by undercutting outwardly through the sidewall 114 about
its circumference as will be apparent. The straps are relatively
short and the space between the sidewall 114 and the breakaway skirt
120 is slight (approximately .005") giving the closure a clean,
elegant look.
As can be seen from Figures 3-6, there is shown a mold or
cavity 142 having an opening 144 to allow the material (iDe.,
polypropylene, polyethylene etc.) to be molded to enter the cavity
when it is placed on the core 146, so as to Form the closure 110.
Accordingly, the outer surface of the core compliments the internal
surface of the closurP 1109 with the internal surface of the cavity
142 complimenting the external surFace of the closure, as shown in
Figure 3. Note however that the inner surface 130 is Formed by a
complimentary surface of an annular V-shaped groove 148 which
similarly comprises two angular surFaces. The upper of these
surfaces 148a includes an undercut means or upper edge 150 which is
approximately of equal diameter as that oF the internal diameter of
the cavity adjacent thereto so that in the molding of the closure a
space is formed (approximately .005") between the sidewall 114 and
the breakaway skirt 120. To provide a frangible portion, connections
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at this junction a plurality o-f notches 152 are provicled on the edge
150 ard serve to allow the forrnation of the straps or connectors 118
on the closure. If the vertical ribs 116 of the closure extend down
to the notches 152, this allows for the straps 118 to be formed out
of a select number of the ribs, depending upon the width of the
notch. Otherwise the straps can be formed out of the sidewall 114.
Turning now to Figure 4, it shows an exploded view of the
molding apparatus which comprises the cavity 142 as aforenoted and
the core generally designated 146. The core 146 comprises three
separate pieces axially displaceable with respect to each other.
The first piece or head section 153 includes a cylindrical head or
stem portion 154 having a helical groove 156 thereon which serves to
form the helical thread of the closure, The head 154 is attached to
a cylindrical shaft 158 which is slidably maintained in a channel 160
formed in the second portion or cylindrical base 162 of the coreu
The base 162 includes a flat annular surface 163 which serves to form
a portion 124 of sidewall 114. Below surface 163 is an annular
V-shaped groove 148 which serves to form the wedge shaped internal
ring 134 of the breakaway skirt 120 as aforenoted. As part of this
groove is surface 148 which terminates in edge 150 having notch 152
located thereon as herebefore described.
Below the groove 148 is an annular smooth surface 164
havins a diameter slightly smaller than the interior sur-face 166 of
the third portion or sleeve 168 which is slidably disposed thereon~
This diameter is approximately equal to that of the edge 150 so as to
allow the sleeve 168 to be axially displaced thereover for reasons
that will be apparent.
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Once the formed closure 110 is formed as shown in Figure 4,
to remove it from the molding apparatus the first step is to remove
the cavity 142 from the core. As shown in Figure 5, the cavity 142
is readi1y axially displaced therefrom in the direction indicated by
the arrows. Next the head portion 153 is axially displaced from the
base 162 which pulls the breakaway skirt 120 from the groove 14~.
Due to the angle of surface 130, this allows for the easing off of
the breakaway skirt 120 to a point beyond edge 150 without Fracturing
the frangible portion 118. Beyond this point, the closure can be
axially withdrawn further and then screwed off of the head section
153. Note that to assist in removal of the closure from the core,
the sleeve 168 moves contemporaneously with the movement of the head
portion 153 as shown in phantom in Figure 6 so as to engage the
bottom 138 of the breakaway skirt 120 and push it or "strip" the
lS closure off the base 162 thereby aiding in preventing a fracture of
the straps 118. Note further that once the closure is off the base
162, it may be unthreaded therefrom by placing a rotational force on
the sidewall 114 so as to unscrew the closure, as is standardly done,
while maintaining the head section 153 fixed. When the closure has
been removed from the core9 the pieces of the core return to their
initial positions as shown in Figure 3 to prepare for the molding of
another closure.
However in certain applications rather than applyiny a
rotational external force on the sidewall 114 and maintaining the
2s head section 153 fixed, an alternate means of removing the closurefrom this section is to hold the closure while turning the head
section. This typically requires vertical lugs or notches to be
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positioned on the closure's interior beneath the -threaded portion.
In this regard, reference is made -to Figures 7 and 8 and which show
alternate embodiments of the core which is similar to that previously
discussed except for providing the lugs or notches, so like parts to
the immediately preceeding embodiment will be similarly numbered and
designated with a prime. As can be seen in Figures 7 and 8, the core
is provided with a plurality of vertical cutouts or notches 170
positioned on the flat annular surface 163 of the head section 153'
and are positioned between the helical groove 154' and edge 150'.
Since these are cutouts9 during molding they will serve to provide
vertical lugs on the interior surface of the closure which should not
be to deep to otherwise interfere with the removal of the closure
from the core, in which to secure the closure while the head section
153' is unthreaded therefrom.
Similarly in Figure 9 rather than forming lugs on the
interior surface of the closure, raised notches are formed thereon by
way of raised lug portions 172 provided on surface 163' and operate
to provide a means of rota-tionally fixing the closure as the head
section is unthreaded therefrom.
Clearly then from the aforenoted invention, the object and
advantages are readily realized and although preferred embodiments
have been disclosed and described in detail herein, its scope should
not be limited thereby rather its scope should be determined by that
of the appended claims.
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