Method and apparatus for injection molding

A method and apparatus are described for forming a closure device having a cylindrical plug and a cylindrical collar extending coextensively and coaxially from a cap. The apparatus includes an outer mold defining an injection mold cavity. A cylindrical hollow outer core extends into the injection mold cavity and a cylindrical inner core extends into the injection mold cavity within the hollow outer core. Pushing means separate the molded part from the inner core. A stripper separates the part from the outer core by engaging an annular shoulder on the part. The part is pushed free of the mold's inner core after the outer mold is removed but before the stripper is advanced to engage the annular shoulder.

FIELD OF THE INVENTION 
This invention relates generally to safety closure devices for use on 
bottles containing pressurized beverages such as champagne or sparkling 
wines. More specifically, the invention relates to an improved safety 
closure device, and to an improved mold and method for making the new 
device. 
BACKGROUND OF THE INVENTION 
The internal pressure inside an unopened bottle of champagne or sparkling 
wine can be as much as 100-150 psi, especially if the contents of the 
bottle are warm or if the bottle has been shaken. Because of this 
pressure, a champagne cork can be propelled from the bottle at a velocity 
of well over 120 Kph. A cork traveling at such a speed can seriously 
injure the person that is opening the bottle as well as individuals that 
are standing nearby. The human eye is especially vulnerable to injury 
because the cup shape of the eye socket mirrors the cup shape of the 
typical champagne cork. Individuals standing near windows or mirrors that 
can be shattered by the force of the flying cork are also vulnerable to 
injury from flying pieces of glass. To make matters worse, as soon as the 
shrink wrap and wire restraining device are removed from the champagne or 
sparkling wine bottle, the corks can explode spontaneously. In such an 
instance there is no opportunity for the person opening the champagne to 
place a towel over the top of the bottle as a means of providing some 
protection against the dangers of the explosive release of the cork. 
The problem of premature or inadvertent explosive release of champagne 
corks is exacerbated by the fact that many lower priced champagnes and 
sparkling wines are closed by molded plastic corks. Plastic corks possess 
an even greater tendency than natural corks to become dislodged as a 
result of internal pressure in the bottle. Wetness on the glass surface of 
the bottle as a result of condensation or seepage of the contents can also 
reduce friction between the surface of the glass and the surface of the 
plastic cork. 
In an attempt to solve the problem of premature or inadvertent release of 
champagne corks, U.S. Pat. No. 4,474,302, issued October, 1984 to 
Goldberg, et al., discloses a closure device (referred to herein as the 
'302 device) that employs a helical tether strip of rounded cross-section 
that is integrally connected to a cap-plug portion and an outer retaining 
collar which fits over the neck of the bottle. When the tear strip is torn 
away, a helical tether strip remains interconnecting the plug or cork and 
the retainer collar. The cork or plug can thus be easily released from the 
bottle, and yet is restrained from flying free. In most instances such 
restraint is sufficient; however laboratory tests of the device showed 
that the helical tether would sometimes break when the cork was released 
from the bottle. 
U.S. Pat. No. 4,564,114, issued Jan. 14, 1986 to Cole, discloses an 
improved tethered safety closure device (referred to herein as the '114 
device) that is similar to the '302 device but differs from it in that the 
'114 device employs a tether of rounded cross-section that is folded upon 
itself, thereby making it stronger than the helical tether of rounded 
cross-section of the U.S. Pat. No. 4,474,302. 
The present invention discloses a new tethered safety closure device that 
utilizes the folded tether design of the '114 device, but improves upon it 
by replacing the rounded cross-section tether portions with tether 
portions of rectangular cross-section. Surprisingly, unlike the rounded 
cross-section tethers, the rectangular cross-section tether portions do 
not significantly distort or collapse when the molded closure devices are 
removed from the mold or when they are initially placed on the bottles of 
champagne or sparkling wine. In addition, the closure device of the 
present invention incorporates an annular shoulder on the device's 
retainer collar as a partial means for removing the finished closure from 
the mold of the present invention. 
U.S. Pat. No. 4,541,795, issued Sep. 17, 1985 to Cole, discloses a mold 
that is especially suited for making the tethered closure devices of the 
'302 and the '114 patents. As the '795 mold patent points out, the molding 
of a plastic closure device is typically carried out in an injection 
molding machine. Such machines usually employ a plurality of die or mold 
plates and, in appropriate cases, a movable core. The mold plates and core 
move once the piece is molded to separate and enable removal of the molded 
device from the mold. 
Where, as is the case with the '302 and the '114 devices, and the improved 
plastic closure device of the present invention, there are two portions 
(i.e., a plug portion and a retaining collar) that extend substantially 
coextensively and coaxially with each other, the molding procedure and 
mold may be extraordinarily complex. With a simple cylindrical device, a 
collapsible mold core may be provided making removal of the molded part 
after molding relatively easy. However, in the present case, a collapsible 
core is not practical due to the presence of the plug portion that is 
coextensive and coaxial with the surrounding cylindrical collar. This 
problem is exacerbated in the present instance because the lower portion 
of the restraining collar contains an annular recess (for mating with a 
retaining ring on the bottle or other container) that has deep undercuts 
on both its inner and outer surfaces. Such undercuts make it very 
difficult to remove the closure device from the mold once the molding 
process is complete. 
The mold of the U.S. Pat. No. 4,541,795 (referred to herein as the '795 
mold) has multiple moving parts. It addresses the problem of the severe 
undercuts on the retaining collar by employing movable mold segments which 
include a gripping portion or means. The gripping means retain the closure 
device while the mold's outer core is extracted from the cavity between 
the plug portion and the inner surface of the closure. Once the core is 
extracted the gripping means separate along with the remainder of the mold 
segments to allow removal of the molded device. 
Unlike the '795 mold, the mold of the present invention has relatively few 
moving mold parts. In addition, the mold has a novel stripper means to 
remove the molded closure device from the mold's outer core means. As 
those skilled in the injection molding arts will appreciate, the fact that 
the mold of the present invention has few moving parts makes it possible 
to have more cavities per mold (for the size of the mold), which in turn 
makes it possible to mold more closures per mold cycle. In addition, the 
design of the mold of the present invention permits placement of more 
cooling channels close to the molding surfaces. This results in greater 
cooling of the newly molded devices, which in turn shortens molding cycle 
times. Consequently, closure devices can be made faster and cheaper in the 
mold of the present invention than they could be made in the '795 mold.

SUMMARY OF THE INVENTION 
Very generally, the improved safety closure device 10 of the invention 
comprises a cap portion 27, a cylindrical plug portion 11 adapted to close 
the mouth of a sparking wine bottle 12 by frictional engagement with the 
bottle's interior facing surface 13, and a cylindrical retainer collar 14 
that fits around the retaining ring or circumferential ridge found on the 
neck of bottles that hold champagne and other sparking wines. Retainer 
collar 14 is coupled to cap 27 and plug portion 11 by a redesigned and 
improved intercoupling section 15. The redesigned intercoupling section 
includes at improved rectangular cross section tether strip portions 16 
that prevent collapse of the device as it is removed from the mold or when 
the device is initially placed on a bottle of champagne or sparkling wine. 
Tether strip 16 is integrally formed with and secured at its respective 
ends 17, 18 to cap 27 and collar 14. (Preferred safety closure devices of 
the invention contain one rectangular cross-section tether strip; less 
preferred safety closure devices of the invention can contain more than 
one rectangular cross-section tether.) In its "unopened" state, 
rectangular cross-section tether strip 16 is folded upon itself, and when 
folded and untorn along the length of the frangible webs, rectangular 
cross-section tether strip 16 sections are from about 0.050 inch (1.269 
mm) to about 0.018 inch (0.457 mm) apart, and preferably from about 0.005 
inch (0.127 mm) to about 0.018 inch apart. Also in its "unopened" state, 
rectangular cross-section tether strip 16 is joined to cap 27 and collar 
14 along a portion of the length of the tether strip by frangible webs 
19,20,21. The webs are of a thickness that permit the tether strip 
portions to be separated along the length of the frangible webs. In the 
preferred safety closure device of the invention, tether strip 16 is 
folded upon itself at least once and is of a length unfolded such that the 
attached capped plug portion may be removed from the bottle or the like 
but is restrained by the collar from flying free. 
The mold and method of the invention are useful for forming a closure 
device 10 having a cap portion 27, a cylindrical plug portion 11 extending 
therefrom, and a cylindrical collar 14 extending substantially 
coextensively and coaxially with the plug portion spaced therefrom to 
provide an annular recess for receiving the open end of the bottle to be 
closed. The mold has a mold cavity that delineates the outer surfaces of 
the closure device to be molded. The cavity is partially defined by upper 
mold segments 103 that delineate the outer surfaces of the cap, and 
lateral mold segments 105 that delineate intercoupling section 15 and 
collar 14. Lateral mold segments 105 include means for molding rectangular 
cross-section tether strip(s) 16 and their interconnecting frangible webs 
19,20, 21, and collar 14 with its annular shoulder 50. The mold cavity for 
the closure device 101 is further defined by a substantially cylindrical 
hollow outer core 109 which extends into the mold cavity and defines the 
annular recess in closure device 10 between collar 14 and plug portion 11. 
In preferred form the mold cavity is further defined by a substantially 
cylindrical inner core 111 that delineates the inner surfaces of the 
device's cylindrical plug portion. Inner core 111 preferably incorporates 
cooling means 112 within it. Outer core 109 is substantially cylindrical; 
it extends into the mold cavity 101 and delineates the annular recess in 
closure device 10 between collar 14 and plug portion 11. Outer core 109 
includes portion 147 that mimics the bottle's circumferential ridge. Inner 
core 111 delineates the inner surfaces of the closure device's plug 
portion. The mold also includes plate portions, some of which are movable. 
The mold's inner and outer cores are attached to plate portions that do 
not move, while pushing means 205 and stripper means 250 are attached to 
plate B that does move by suitable supports 450. Sequential movement of 
the movable B plate (and the attached pushing means) enables pushing means 
205 to push on plate D, thus pushing molded closure device 10 away from 
the mold's inner core 111. Additional movement of the B plate enables 
stripper means 250 to engage annular shoulder 50 on collar 14 of closure 
device 10. Still more movement of plate B enables stripper means 250 to 
push molded closure device 10 past outer core portion 147 (which mimics 
the bottle's circumferential ridge 34) and past the portion that 
delineates the plug portion's gripping ridges 37. As a result the molded 
device is freed from the mold. See FIGS. 4 and 10. 
DETAILED DESCRIPTION OF THE INVENTION 
The Closure Device 
The improved safety closure device of the present invention is illustrated 
in FIGS. 1 through 4. In FIGS. 1 and 2 the safety closure device is shown 
mounted on the neck of a bottle 12 designed to hold pressurized liquids 
such as champagne or other sparkling wines. The device of the invention 
includes a cylindrical closure element or plug portion 11 and a retainer 
collar 14 that are joined by an improved intercoupling section 15. 
The bottle 12 in FIGS. 1 and 2 is typical of bottles used to contain 
champagne and sparkling Wines. Such bottles often have elongated, tapered, 
cylindrical necks containing a circumferential bulge or ridge 34 (known to 
the trade as a "retaining ring" or "finishing bead") a distance below lip 
25 at the top of the bottle. The circumferential ridge 34 protrudes from 
the side of the bottle with sufficient radius to provide a means for 
restraining or impeding objects or devices, fastened above or below it, 
from moving up or down the neck of the bottle. In the past, such objects 
and devices have included, for example, woven wire baskets used to 
restrain plugs or corks. In the present invention, the circumferential 
ridge 34 is used to restrain retainer collar 14. 
The closure device of the invention is preferably formed of a molded 
unitary piece or a suitable resilient substance. While polymerized plastic 
(such as FDA approved 800 series polyethelene) is a preferable resilient 
substance because it allows the lower annular portion 47 of retainer 
collar 14 to expand over the bottle's circumferential ridge 34, other 
resilient substances are suitable as long as they are weak in shear when 
thin but strong in tension when thick. As used herein, "weak in shear when 
thin" means a substance that is manually tearable when used at the 
thickness of the thin frangible webs 19,20,21 that interconnect the untorn 
tether strip portions to cap 27 and collar 14. "Strong in tension when 
thick" means that, at the thickness of the tether strip, the substance is 
strong enough to withstand longitudinal strain caused by sudden release of 
the cork from the bottle. 
For purposes of this invention, a suitable resilient substance will be 
moldable. A suitable resilient substance will also have sufficient 
resiliency to allow retainer collar 14 to stretch circumferentially but 
not break as it is inserted over the neck of the bottle, including the 
circumferential ridge 34. Following the expansion necessary to allow the 
tapered lower annular portion 47 on retainer collar 14 to pass over the 
circumferential ridge 34, a suitable material will still have sufficient 
resiliency to allow the collar to assume a shape that conforms generally 
to the contour of the outside of the bottle with sufficient force to be 
retained despite stresses exerted from the pressurized contents of the 
bottle. 
Closure device 10 includes a cap 27 of generally cup-like shape. Cap 27 is 
comprised of a circular disklike top portion 29 integrally molded with a 
hollow cylindrical side portion 31. The diameter of the cap's circular top 
portion 29 is greater than the diameter of the opening in the top of the 
bottle at lip 25. The inner circumference of the cap's hollow cylindrical 
side portion is slightly larger than the outer circumference of lip 25 at 
the top of bottle 12. 
Plug portion 11 is preferably hollow having an outer cylindrical wall 
surface 33 (FIG. 3) and an inner cylindrical wall surface 35. Plug portion 
11 has an outer diameter at surface 33 that is very slightly smaller than 
the diameters of the opening at the top of the bottle and the upper inner 
portions of the bottle neck. This size differential allows plug portion 11 
of closure device 10 to fit tightly down into the neck of the bottle. In 
the preferred device of the invention a series of parallel annular ridges 
37 protrude slightly from the outer wall surface 33 about halfway down the 
length of plug portion 11. The width and height of the annular ridges are 
approximately equal. These annular ridges continue down the outer wall 
surface 33 of plug portion 11 to a point approximately at or slightly 
below the bottle's circumferential ridge 34 when closure device 10 is in 
place in bottle 12. When the closure device is in the bottle, outer 
circumferential wall 33 of the plug portion 11 supports the annular ridges 
37 against the inner wall of the bottle neck. As a result, the annular 
ridges push against the inner facing surface 13 of bottle 12 helping to 
seal its contents. 
Plug portion 11 is adapted to close the mouth of bottle 12 by frictional 
engagement with the interior facing surface 13 of the mouth. Intercoupling 
section 15 couples collar 14 to cap 27 on closure device 10. In the 
preferred device of the invention, intercoupling section 15 is comprised 
essentially of at least one rectangular cross-section tether strip 16 and 
interconnecting frangible webs 19,20,21 formed integrally in the 
intercoupling section. One end 17 of tether strip 16 is secured to cap 27, 
the other end 18 is secured to collar 14. Tether strip 16 is preferably 
folded once on itself and the two tether portions are interconnected by 
grooved frangible webs 19,20,21. The thickness and configuration of 
frangible webs 19,20,21 are preselected to be less than the thickness of 
tether strip 16. Tether strip 16 preferably contains an integral pull tab 
portion 42 at the area of its fold which provides an easy and convenient 
means for grasping the tether strip 16 prior to its separation as 
described below. 
The finger-grip section of tab portion 42 of tether strip 16 may be 
suitably roughened, not shown, to help prevent the tab from slipping when 
grasped by a person wishing to separate the tether strip portions. In the 
closure device of the present invention, a plurality of parallel stays 43 
preferably extend along the tab portion 42, the tab portion being 
thickened so as to be non-frangible from the free tip of the tab 42 to the 
end of the frangible web 21 at the fold 600 of the tether strap 16. This 
acts to stiffen and strengthen this section of tab portion 41. (See FIGS. 
1 and 2.) 
Retainer collar 14 is comprised of a hollow annular portion that fits 
around the top outside portion of the bottle neck. The interior shape of 
retainer collar 14 generally mirrors the contour of the outer surfaces of 
sparkling wine bottle 12. In the improved closure device of the present 
invention, collar 14 contains an annular shoulder 50 (see FIG. 3) that 
facilitates removal of the closure device from the mold of the invention. 
Just below the annular shoulder 50, collar 14 contains a tapered annular 
portion 47. The size and shape of the inner surface of annular portion 47 
generally mirrors and approximates the shape and size of the lower portion 
of circumferential ridge 34 on bottle 12. 
The location of annular shoulder 50 relative to the mold part that mimics 
circumferential ridge 34 is critical to the ability to remove finished 
molded closure device 10 from the mold of the present invention. As those 
skilled in the art will appreciate, the shape and position of 
circumferential ridges will vary depending on the size of the bottle and 
which manufacturer made it. As a result the shape and position of mold 
portions that mimic the circumferential ridges will differ as well. 
Although such variations make it impractical to list precise locations for 
the annular shoulder on any particular closure device (since the closure 
device of the present invention can be adapted for use on any of these 
bottles that have circumferential ridges), the following functional 
definition can be used without undue experimentation by those skilled in 
the art to determine what constitutes a proper location of the shoulder 
when the closure device is being adapted for a particular bottle. 
When shoulder 50 is positioned correctly on collar 14, shoulder 50 
functions to aid in the removal of the finished molded closure lo device 
from the mold. More specifically, during the mold's ejection process, the 
mold's stripper means 250 (which will be discussed more fully below) 
engages shoulder 50 and pushes against it. As a result, as stripper means 
250 advances, the lower tapered annular portion 47 of collar 14 stretches 
circumferentially as it is pushed up and around the mold portion (referred 
to herein as 147) that mimics the bottle's circumferential ridge 34. If 
shoulder 50 is positioned too low on collar 14, stripper means 250 will 
inhibit the expansion required for the collar's lower tapered annular 
portion 47 to clear mold portion 147. On the other hand, if shoulder 50 is 
located too high on collar 14, stripper means 250 may disengage from 
shoulder 50 during the ejection process. When shoulder 50 is positioned 
correctly, the circumferential expansion of lower tapered collar portion 
47, that results as molded closure device 10 is pushed by stripper means 
250 up and around mold portion 147, causes the "expanded" collar to push 
against stripper means 250. This in turn helps secure edge 251 of stripper 
means 250 tightly against the lower edge of shoulder 50. When shoulder 50 
is placed too high on collar 14, the expanded collar does not push against 
stripper means 250 as much, which makes it easier for stripper means 250 
to disengage from annular shoulder 50 on collar 14. 
By way of example, with regard to the bottle and closure device shown in 
the figures, the following are preferred: (1) the location of shoulder 50 
must be as vertically shown, plus or minus 0.005 inch (0.127 mm) in order 
for removal of the device from the mold to function as described herein, 
(2) the inside diameter of edge 251 of stripper bar 250 must be within 
0.002 inch (0.058 mm) of the relative positions that are shown in order 
for the device to be removed properly from the mold, (3) the shown shape 
of trough 252 is critical for proper functioning of removal of the device 
from the mold. Those skilled in the art, using the present disclosure, can 
adjust these exemplified tolerances, without undue experimentation, to fit 
other bottles used in the sparkling wine and champagne industries. 
When tethered safety closure device 10 is installed on a sparkling wine 
bottle, collar 14, and especially lower annular portion 47, fits around 
the circumferential ridge 34 on the neck of the bottle and holds the 
collar in place. Additional security of the collar on the bottle neck is 
assured by providing sufficient thickness in the wall of the collar below 
annular shoulder 50 to prevent circumferential expansion and consequent 
upward movement of the collar 14 as a result of pressure in the bottle. 
Tether strip 16 is folded upon itself a single time in the illustrated 
embodiment and is of a length unfolded such that plug portion 11 may be 
removed from the bottle. (Although the illustrated embodiment shows a 
single fold, other numbers of folds could be used.) However, regardless of 
the number of folds, the length of the tether strip unfolded is such as to 
restrain cap 27 and attached plug portion 11 from flying free of the 
bottle with the attendant possibility of injury. Preferably, the length of 
tether strip 16 is between 6 centimeters and 10 centimeters. 
Tether strip 16 is interconnected with cap 27 of closure device 10 by 
frangible web section 19 and is connected to the collar 14 by frangible 
web section 20. The webs 19 and 20 are of a thickness and configuration 
preselected to be less than the thickness of tether strip 16 for reasons 
explained below. 
When pull tab portion 42 of tether strip 16 is grasped and pulled by one 
wishing to open a bottle of sparkling wine, tether strip 16 separates from 
cap 27 and collar 14 along the length of the frangible portion of the 
tether strip because of a tearing of frangible web sections 19,20,21 along 
the path of grooves that separate rectangular cross-section tether strip 
16. When tether strip 16 is torn along the path of the grooves, it still 
remains to interconnected cap 27 to collar 14, thus enabling plug portion 
11 to be released from the bottle 12 without flying free. 
Webs 19,20,21 may be continuous, or may be broken by a series of openings, 
not shown, which facilitate separation of tether strip 16. The strength of 
the webs is selected, however, to provide sufficient strength to maintain 
a cohesive structure until separation of the tether strip portions. Tether 
strip 16 is separable by manually causing the webs to tear. (If pressure 
within a bottle of sparkling wine builds to the point that the cork or 
closure device is released spontaneously, the explosive force of the 
closure device Will be the cause of a tearing of webs 19,20,21 between 
tether strip 16. However, as indicated below, the tether will keep the 
cork from flying free.) Following the tearing of the webs 19,20,21 as 
shown in FIG. 2, rectangular cross-section tether strip 16 remains 
attached to cap portion 27 and to collar 14. These attachments are 
preferably accomplished by means of a merging brought about by a gradual 
diminution of the depth of the groove separating the cap or collar 
material from the ends of the tether turns at terminal regions 17 and 18. 
The improved closure device of the present invention has a rectangular 
cross-section tether rather than the round cross-sectioned ones of the 
prior art (e.g., the '114 and the '302 devices referred to in the 
Background section of this specification). (As used herein, rectangular 
cross-section tether means that in cross-section the tether is 
substantially like a rectangle having corners with right angles; in 
contrast, round cross-section tether means that in cross section the outer 
edge of the tether is rounded or substantially arc-like or curved.) In 
addition to being substantially rectangular in cross-section, tether 16 is 
preferably of a size and mass sufficient to prevent rupture under tensile 
stress in excess of about 200 psi at about 20.degree. C. The new 
rectangular cross-section design of tether 16 is critical because it 
prevents intercoupling section 15 from collapsing when intercoupling 
section 15 undergoes longitudinal compression force in a direction 
parallel to the long-axis of closure device 10. This compression force 
occurs under the following two sets of circumstances: (1) when closure 
device 10 is being removed from the mold of the present invention, 
stripper means 250 exerts pressure at shoulder 50, which in turn must 
transmit the force via cap portion 31 to plug portion 11 in order to free 
parallel annular ridges 37 from outer core mold means 109; and (2) when 
closure device 10 is placed on a bottle 12 containing sparkling wine, 
pressure on cap 27 or its circular disklike top portion 29 is transmitted 
through intercoupling means 15 to collar 14, thus forcing collar 14 to 
momentarily stretch circumferentially so that the collar can slip over the 
bottle's circumferential ridge 34. 
When longitudinal compression force is applied to the improved rectangular 
cross-section tethered device of the present invention, the spaces 
occupied by webs 19,20,21 collapse like an accordion, thus allowing one 
rectangular cross-section surface of tether 16 to make direct contact with 
or otherwise engage an adjacent rectangular cross-section tether surface. 
Such direct contact of these surfaces effectively transmits the 
compression force longitudinally up or down the closure device. Prior art 
tethered closure devices, such as the '114 and '302 devices, which have 
round cross-section tethers, do not allow the tether surfaces to make 
comparable direct contact with one another when longitudinal compression 
forces are applied to these devices. As a result, some of the compression 
force is channeled inwardly, and if the force is great enough, the 
intercoupling section of the device collapses. The more rectangular the 
tethers 16, the more efficient they will be in transmitting the 
compression force longitudinally. Furthermore, when the untorn rectangular 
cross section tethers are at least about 0.005 inch apart but not more 
than about 0.05 inch apart, and preferably not more than about 0.018 inch 
apart, the compression force is effectively transmitted up or down the 
closure device. With regard to a closure device designed to fit on a 
standard bottle used in the sparkling wine industry, a distance between 
the tethers 16 of about 0.005 inch to 0.018 inch also allows control of 
the direction of tearing in the illustrated closure device. These values 
can be adjusted by those skilled in the arts of mold designs, without 
undue experimentation, for closure devices that fit other standard bottle 
shapes and sizes. 
Because of the design of the tethered safety closure device and the 
material used to construct it, the unitary tethered safety closure device 
of the present invention can easily be inserted on bottles containing 
champagne or sparkling wine. The thickness at the bottom of the retaining 
collar is selected to facilitate placing the device on the wine bottle. 
The resiliency of the material used to make the tethered safety closure 
device allows it to expand and contract as necessary to fit securely in 
and around the neck of the bottle. This resiliency can be increased with 
heat if the properties of the material so warrant. 
In addition to providing the means for connecting cap 27 to retainer collar 
14, intercoupling section 15 creates an integral tamper proof safety seal 
between cap 27 and collar 14 because it indicates by dismemberment if the 
product has been prematurely opened. 
The Mold and Method 
The mold of the invention is shown in FIGS. 6-10. Very generally, the mold 
comprises mold means 103, 105, which enclose mold cavity 101 that defines 
the outer surface of the closure device to be molded. A substantially 
cylindrical hollow outer core means 109 extends into the mold cavity and 
defines the annular cavity in closure device 10, including the inner 
surface of cylindrical collar 14 and the outer surface of cylindrical plug 
portion 11. In addition, a substantially cylindrical inner core means 111 
may extend into the mold cavity; the inner core mold means define the 
inner surface of cylindrical plug portion 11 when the plug portion is 
hollow. See FIG. 6 for detail. 
Referring now more particularly to FIG. 6, a preferred form of the mold of 
the invention is illustrated in position in a multi-mold plate injection 
molding machine. The mold cavity is defined by an upper mold segment means 
103, lateral mold segment means 105, substantially cylindrical outer core 
mold means 109 and substantially cylindrical inner core mold means 111. 
Upper mold segment means 103 is formed to have a cavity surface defining 
the outer surface of the cup-like cap 27 of closure device 10. Lateral 
mold segment means 105 are shaped to form the outer surfaces of the 
closure device's intercoupling section 15 (comprising the tether region) 
and the outer surface of collar 14, including annular shoulder 50 and 
lower annular portion 47. Outer core mold means 109 is shaped to define 
the recess between cylindrical plug portion 11 and the following: collar 
14, intercoupling section 15 and cap portion 27. Inner core mold means 111 
defines the interior surface of the cylindrical plug portion 11 of closure 
device 10, which in the illustrated embodiment is hollow. Completing the 
mold means are multiple water or cooling means 112 within lateral mold 
segments 105, and at least one cooling means within cylindrical inner core 
means 111 and upper mold means 103. 
It may be noted from FIG. 6 that lateral mold segment means 105 and outer 
core mold means 109 engage each other to close the mold cavity. Similarly, 
outer core mold means 109 and inner core mold means 111 engage at the 
lower end of plug 11 to close mold cavity 101. The outer Wall of outer 
core mold means 109 is provided with a suitable shape to conform with the 
inner surface of the collar 14 and cup shaped portion of the cap 27, and 
includes an annular protuberance or circumferential ring 147 which forms 
the annular recess in the inner surface of collar 14. Rectangular 
cross-section grooves 106 are provided in lateral mold segments 105 at 
suitable locations to form rectangular cross-section tethers 16. 
The injection mold, as may be seen in FIGS. 6 through 10, comprises mold 
plates that are described in detail below and which carry the various 
parts of the mold means that form mold cavity 101. The mold means that 
delineate the outer surfaces of the closure device are carried on movable 
mold plates, while those that delineate the device's inner recesses (i.e., 
inner core mold means 111) are attached to plates that do not move. 
Pushing means 205 and stripper means 250 are also attached to movable mold 
plates. In this way, after the device is molded, sequential movement of 
the movable plates enables the closure device to be removed from the mold. 
Since injection molding machines are well known in the art they will be 
not be described in detail herein other than with respect to the 
particular method of the present invention. 
The mold illustrated in FIG. 6 includes an upper mold segment means 103 
which has a recess 141 therein of dual stepped diameter. Upper mold 
segment 103, which is carried on a mold plate F, is provided with a recess 
127 therein which also includes a frustoconical section 129. A hot tip or 
hot runner 131 of any suitable type known in the art is positioned in the 
cavity formed by recesses 127 and 129. Hot tip 131 has a central passage 
133 therein through which molten material is injected into mold cavity 
101. A corresponding passage 134 is provided in upper mold segment 103 
aligned with the passage 133 to complete the route for the injected 
material to the mold cavity. At least one coolant passage 112 is 
preferably provided in the outer surface of upper mold segment 103. 
The molding apparatus is constructed of a series of plates which will now 
be described. Plate A is lowermost, and contains recesses and spaces in 
which plate B can move. Plate A is attached to a standard molding machine 
(not shown). Plate A supports plate C by attachment means 293 at surface 
297. Plate B consists of two metal plates B1 and B2 which are suitably 
united by means not shown. Stepped holes in B2 provide a means for 
fastening support rods 450 for stripper means 250 and pushing means 205 to 
plate B. plate C consists of two metal plates C1 and C2 that are joined by 
means not shown. Stepped holes 183 and 185 in plate C2 provide support and 
attachment for inner core mold means 111. Holes are also provided in plate 
C1 for the passage of pushing means 205. Matching holes are provided in 
plate C2 for the upper part of pushing means 205 and for suitable 
frictional engagement of cam 210, which will be described in more detail 
below. Holes are also provided in plates C1 and C2 for support rods 450 
for stripper means 250. 
Plate D consists of two metal plates D1 and D2 that are joined by means not 
shown. Holes are provided in plates D2 and D1 for the passage of support 
rods 450 of stripper means 250 and inner core mold means 111. A stepped 
hole 151 is provided in plate D2 to support outer core mold means 109 and 
fasten them to plate D. Holes 325 are provided in plate D2 to give 
clearance for slanted shoulder pins 317. A detente mechanism 152 
consisting of a spring-loaded ball is provided in plate D2 to lock plate E 
in position after movement. Plate E consists of two movable portions 190 
and 191 which separate during the ejection cycle. Plate E portions 190 and 
191 are firmly preset together when the mold is closed by angle bars 192, 
which press against the angled surfaces 193 of plate portions 190 and 191. 
Plate portions 190 and 191 also contain angled holes 194 (FIGS. 8 and 9) 
into which slanted shoulder pins 317 descend and slide during mold 
closure. Plate portions 190 and 191 additionally provide grooves 195 for 
clearance for stripper means 250, and contain stepped holes that provide a 
housing chamber for the upper mold means 105 that mold intercoupling 
portion 15. 
Lower ejector housing plate A, in the operation of the molding machine, is 
suitably supported, by means not shown, in a fixed position. Pushing means 
205 and support rods 450 for stripper means 250 are attached to movable 
ejector plate B. Shoulder bolt 293 extends through passage 295 in plate A 
and attaches support post 500 to plate A. 
A slanted shoulder pin 317, fixed to the mold plate G by a flange 319, 
extends through mold plate F, and through openings 321, 194 and 325 in 
mold plates F, E and D, respectively. Opening 325 is shaped so as to clear 
the end of angled pin 317 when plates F and G are moved vertically upward, 
as will be described below. A second slanted shoulder pin is provided as a 
mirror image to the pin 317. 
It will be noted by comparing FIGS. 7 and 8 that, as plates F and G move 
upwardly, pin 317 exerts a lateral or horizontal component of force on 
part 190 of plate E in a direction away from the mold cavity. As stated 
above, a pin similar to pin 317 is provided on the opposite side of the 
mold cavity in a mirror image configuration. The horizontal forces exerted 
on plate E by pin 317 and its mirror image pin cause separation of lateral 
mold segment means 105 carried on plate portions 109, 191 of plate E along 
the parting plane. This causes a withdrawing of the rectangular 
cross-sectioned grooved portion (which forms tether 16 and webs 19,20,21) 
and the collar forming portion of lateral mold segment means 105 from 
engagement With newly molded closure device 10. 
Cooling means 112 preferably circulate throughout the entire length of 
inner core mold means 111; such cooling aids in "setting" the molded 
closure devices, and thus shortens mold cycle times. 
After the elapse of a period of time sufficient to permit a desired degree 
of solidification of the injected material, the molding machine first 
operates to move the die plates G, F, and E to the positions shown in FIG. 
8 relative to the plates D, C, B and A. In this position, mold plates G 
and F and upper mold segment means 103 are separated from engagement with 
lateral mold segment means 105 and plate E. In addition, lateral mold 
means 105 and mold plate E are separated from the molded closure device 
10. See FIG. 8. 
In the condition shown in FIG. 9, movable plate B has been made to advance. 
Because cam 210 on pushing means 205 abuts shoulder 215 in opening 213 in 
plate D1 (see FIG. 8) advancement of movable plate B (to which pushing 
means 205 are attached) causes a concomitant movement in plates E, D2 and 
D1 Pushing means 205 passes through openings in plate C, which is 
stationary. Since mold plate C is stationary, inner core mold means 111 
(which is attached thereto) is stationary as well. As a result, as mold 
plates D and E advance forward, molded closure device 10 is pulled away 
from the mold's inner core means 111. See FIG. 9. 
The final stages of the ejection process are shown in FIG. 4 (which shows 
detail of how stripper means 250 engages annular shoulder 50 on the 
surface of retainer collar 14) and FIG. 10. These final stages are the 
most difficult of the ejection process since molded closure device 10 must 
be "pushed" up and over annular protuberance 147 on the outer wall of the 
mold's outer core means 109. They are accomplished by further forward 
movement of plate B, which is made to move in the following manner. Cam 
210 is made to separate (by means not shown) from pushing means 205, thus 
allowing pushing means 205 to advance into opening 213 in plate D. Since 
both pushing means 205 and stripper means 250 are attached to movable 
plate B, as pushing means 205 moves into opening 213, plate B (and 
stripper means 250) advances as well. 
Turning now to FIG. 4, which shows the stripper means in greater detail, it 
can be seen that stripper means 250 has a wedged edge 251 with a small 
trough or depression 252 in it at the point where stripper means 250 comes 
in contact with annular shoulder 50 on the outer surface of retainer 
collar 14. As the stripper means 250 advances forward, trough 252 in edge 
251 allows increased frictional stability between edge 251 and annular 
shoulder 50. As plate B advances, stripper means 250 provides the force 
needed to push closure device 10 up and around annular protuberance 147 on 
the outer surface of outer core mold means 109. 
As closure device 10 is pushed up and around annular protuberance 147, the 
portion of collar 14 that lies below annular shoulder 50 is distorted as 
it moves around the deep undercut on protuberance 147. The natural 
resilience of the moldable material permits collar 14 to regain its shape 
after passing over annular protuberance 147. Following separation of 
molded device 10 from the mold's outer core 109 the molded device falls 
free of the mold. 
After achieving the positions shown in FIG. 10, the plates reverse their 
motions to return to the positions shown in FIG. 7, and the cycle is 
completed. 
From the foregoing description, one of ordinary skill in the art can 
understand that the present invention is an improved safety closure 
device, injection mold and molding method are described. The safety 
closure device has a cap portion; a cylindrical plug portion extending 
therefrom; a cylindrical collar extending substantially coextensively and 
coaxially with the plug portion spaced therefrom to provide an annular 
recess for receiving the open end of the container to be closed; and an 
improved intercoupling portion comprised of at least one rectangular 
cross-section tether strip that is interconnected alone its edges by 
frangible webs and secured at its respective ends to the cap and the 
collar. The tether strip is folded upon itself at least once and is of a 
length that, after the frangible webs have been torn, the attached cap and 
plug can be removed from the bottle without flying free. 
The mold has a mold cavity that delineates the outer surfaces of the 
closure device to be molded. The cavity is partially defined by upper mold 
segments that delineate the outer surfaces of the cap and lateral mold 
segments that delineate the intercoupling section and the collar. The 
lateral mold segments include means for molding the rectangular 
cross-section tether strip(s) and their interconnecting frangible webs, 
and the collar with its annular shoulder. The mold cavity is further 
defined by a substantially cylindrical hollow outer core which extends 
into the mold cavity and defines the annular recess in the closure device 
between the collar and the plug portion. In preferred form the mold cavity 
is further defined by a substantially cylindrical inner core that 
delineates the inner surfaces of the device's cylindrical plug portion. 
The mold preferably includes pushing means for separating the finished 
molded closure device from the mold's inner core and stripper means for 
separating the finished device from the mold's outer core. 
Various modifications of the invention in addition to those shown and 
described herein will become apparent to those skilled in the art from the 
foregoing description and accompanying drawings. Such modifications are 
intended to fall within the scope of the appended claims.