Note: Descriptions are shown in the official language in which they were submitted.
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IMPROVED CHILD-RESISTANT CAP FOR LIQUID MEDICAMENTS
FIELD OF THE INVENTION
[00011 The invention relates to improvements to child-resistant closures
for
dispensers of liquid medicaments, in particular dispensers of liquid
ophthalmic and nasal
medicaments, and thereby provides enhanced safety of the dispensers by making
the contents
of the containers less susceptible to access by children.
BACKGROUND OF THE INVENTION
[0002] Child-resistant caps for medicaments have been known in the art for
nearly
fifty years. These caps generally require two opposed movements acting at the
same time to
overcome the locking mechanism. For example, one type of cap requires a user
to squeeze
the cap at specific points, causing a deformation, and then to rotate the cap.
If either the
squeezing or rotating step is not performed, the cap cannot be opened. Another
common
method for imparting child-resistance on a cap is to require that the cap be
pushed in a
downward direction and then turned in order to be removed. Again, it can be
seen that the
two movements are opposed to one another; it is only through application of
this unnatural
combination of movements that the cap can be removed. Such a cap is disclosed
in U.S.
Patent 5,316,161.
[0003] However, several issues arose with implementation of prior art
caps. Such
caps utilized unequal numbers of lugs and their mates; that is to say, in a
two-piece closure,
the prior art taught a greater number of lugs, beams, or fingers on an inner
shell than the
corresponding number of lugs, beams, or fingers on an outer shell or vice-
versa. This meant
that not all of the lugs, beams, or fingers of one shell were being engaged.
This lack of
engagement allowed for slippage during the rotational process, which can lead
to damage to
the lugs, beams, and fingers of both the outer and inner caps. Such damage
often manifested
itself in the form of stripping of the lugs, beams, and fingers. When these
parts become
stripped, the user is required to apply greater downward force to engage the
appropriate
mechanisms. However, the application of this downward force would often result
in
additional damage to the lugs, beams, or fingers. Additionally, prior art caps
utilized flexible
lugs, beams, or fingers with an angled underside. This angled underside
presented problems
in that it would concentrate flexion at a very specific point which would
often weaken the
lug, beam, or finger.
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[0004] When excess force is applied to flexible lugs, beams, or fingers,
they are
often forced to flex beyond their capabilities. This hyper-flexion can result
in a permanent
deformation and even complete breakage of the lugs, beams, or fingers. In
lugs, beams, or
fingers having an angled underside, breakage often occurred immediately above
the angle.
Once breakage has occurred, whether above the angle or elsewhere, the deformed
or broken
lugs, beams, or fingers may no longer exert a contrary or biasing force on
other component
parts of the cap. In such situations, no downward force is necessary for
removal, leaving
only a rotational force required to remove the cap. Therefore, the cap is no
longer child-
resistant.
[0005] Additionally, prior art caps often permitted an outer cap to float
above and
rotate unhindered about an inner cap until the application of a downward
force. However, a
major complaint of child-resistant caps has been that they are difficult for
the elderly and
infirm to remove. With free-floating caps, the elderly often have a difficult
time applying the
appropriate amount of downward force necessary to get the appropriate lugs,
beams, or
fingers to engage. Similarly, the elderly often have a difficult time
maintaining the
appropriate downward force throughout the rotational movement. When applied to
prior art
caps, this lack of coordination and partial engagement would result in
frustration on the part
of the user. Redoubled efforts often resulted in damage to the elements of the
cap, through
the combination of improper alignment and application of excess force, albeit
briefly applied.
This was manifested in the crushing of certain portions or the stripping of
others.
Additionally, when excess force is applied to a misaligned cap, portions of
the cap may jam,
requiring additional unconventional movements to clear the jam. These
unconventional
movements may damage the cap, again leading to decreased, if not eliminated,
child-
resistance.
[0006] Similarly, an additional problem of prior art caps is that they
require a
downward force to apply them to a pre-existing bottle. This is especially
important to
manufacturers, as machines capable of applying a downward force are more
expensive than
those which only apply a rotational force. Work-arounds have been designed,
however they
are expensive and can often involve re-tooling of a machine, at a cost which
eats into the
profit margin of the manufacturer. Additionally, on machines imparting a
downward force
(whether through original design or through later modifications), the amount
and timing of
downward force must be carefully calculated and must remain within specific
tolerances. If
the machine ventures too far beyond these tolerances, excess downward force
may be applied
to the cap as it is being affixed to the pre-existing bottle, and damage to
the lugs, beams, and
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fingers may result. As mentioned above, such damage includes, but is not
limited to,
deformation or breakage of the lugs, beams, or fingers, as well as crushing of
other various
critical components of the cap.
[0007] Finally, when prior art child-resistant closure mechanisms were
applied to
dispensers of liquid medicaments, their design did not significantly differ
from bottles for
pill-form medicaments. That is to say, the shape of the cap was cylindrical,
which created a
large interior cavity where medicament could pool when the bottle was inverted
while the cap
was affixed thereto. In such prior art caps, a large quantity of residual
medicament would
then remain in the cap upon removal. Should a young child obtain access to
this
medicament-laden cap, it would be possible for the child to ingest significant
quantities of the
liquid medicament simply by removing the residual amount stored in the inner
chamber of
the cap.
100081 As a result, in light of the foregoing, it is clear that there is
an unmet need in
the art. The prior art caps are prone to damage resulting in loss of child-
resistant qualities,
and further, may unintentionally provide access to significant amounts of
residual liquid
medicament stored in the removed cap. Specifically, there has been a need for
a cap: (1)
which reduces potential for damage to component parts through full engagement
of lugs,
beams, or fingers, (2) prevents over-flexion of lugs, beams, or fingers, (3)
modifies the shape
of lugs, beams, or fingers, (4) allows the elderly to more easily remove the
cap, (5) provides
for easier application of the cap by manufacturing processes while at the same
time reducing
the likelihood of damage to the cap, and (6) minimizes the amount of residual
medicament
accessible to a child in possession of the removed cap.
BRIEF SUMMARY OF THE INVENTION
100091 The present invention provides an improved child-resistant closure
for liquid
ophthalmic and nasal medicaments, as well as a system for providing child-
resistant closure
of an existing bottle, and a method of application and removal, providing ease
of application
during the bottling phase and enhanced child-resistant properties once the
apparatus and
system have been distributed to an end user.
[0010] One embodiment of the closure provides for a cap with matching
numbers of
complementary lugs and beams, with the flexible beams having an angled ridge
with an
arcuate underside. Additional embodiments of the closure include the
requirement that an
underside of an upper lug overlap a lower flexible beam by a predetermined
distance or range
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of distances when the lug faces of upper lugs are properly aligned. These
embodiments
improve upon the reliability of a child-resistant closure by ensuring that it
is only engaged
when properly aligned, providing ideal frictional contact, and preventing
undue stress upon
the flexible beams when a downward force has been applied to them. Additional
embodiments include modifications to a top portion of the cap, wherein one
embodiment
provides for a flat top and an alternative embodiment provides for a shaped
top,
complementary to the shape of a dispenser of liquid medicaments, to minimize
the internal
volume available for unintentional pooling of excess medicament.
100111 An additional embodiment of the invention is a system in which
flexion of
the flexible beams is limited such that the beam head does not extend below
the beam base of
an adjacent flexible beam. By limiting such flexion, the beams are not damaged
by hyper-
flexion. The prior art does not address this issue, and by permitting beams to
be
unnecessarily hyper-flexed, the resiliency of the beam is decreased, often to
the point where
no downward force is necessary to engage the lugs of the cap, and the child-
resistant nature
of the cap has been eliminated.
[0012] The final embodiments of the invention relate to methods for
attaching and
removing the closure from a bottle containing liquid medicaments. In one
embodiment, the
steps of applying a downward force and rotating the outer cap are sequential.
In another
embodiment, the steps are simultaneous. However, the present invention
advantageously
eliminates the requirement of a constant downward force, such elimination
being beneficial
for elderly populations or those with arthritis. The final embodiment of the
invention relates
to the manner in which the invention is affixed to a bottle containing liquid
medicaments. In
this embodiment, no downward force is necessary. As a result, the present
method is
advantageous in that it does not require a re-tooling of present cap-applying
machinery which
lack the ability to exert a downward force. By providing for a method in which
no downward
force is needed, not only are more machines capable of affixing the cap to the
bottle, but
there is also a reduction in the likelihood of damage to the flexible beams
due to
misealibrations in the amount of downward force required.
[0013] Additional objects, advantages and novel features of the invention
will be set
forth in part in the description, examples and figures which follow, all of
which are intended
to be for illustrative purposes only, and not intended in any way to limit the
invention, and in
part will become apparent to those skilled in the art on examination of the
following, or may
be learned by practice of the invention.
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I3R1EF DESCRIPTION OF THE FIGURES
[0014] The foregoing summary, as well as the following detailed description
of the
invention, will be better understood when read in conjunction with the
appended drawings. It
should be understood, however, that the invention is not limited to the
precise arrangements
and instrumentalities shown.
[0015] Figure 1 shows the improved child-resistant cap.
[0016] Figures 2A-2C show multiple views of the outer cap.
[0017] Figures 3A-3C show multiple views of the inner cap.
[0018] Figures 4A-4B show a cap with top sections complementary to the
shape of a
dispenser nozzle for liquid medicaments affixed to a pre-existing bottle.
[0019] Figure 5 shows the overlap of the skirt lug with the flexible beams
when lug
faces of the shoulder lugs are aligned.
[0020] Figures 6A-6C shows the movements of the skirt lugs of the outer cap
and the
flexible beam of the inner cap as the outer cap is rotated counter-clockwise
relative to the
inner cap.
[0021] Figure 7 shows the flexible beam when the lug faces of the shoulder
lugs of
the inner and outer caps have been aligned and a downward force has been
applied to the
outer cap.
[0022] Figure 8 shows engagement of the flexible beam and the skirt lugs
required to
thread the cap onto a bottle.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE
INVENTION
[0023] For the purposes of the present disclosure, the term "overlap" shall
be
understood to mean the horizontal distance measured from the vertical plane of
a lug face of a
skirt lug to the vertical plane of the nearest beam face of a flexible beam,
when the lug faces
of shoulder lugs on inner and outer caps are aligned.
[0024] For the purposes of the present disclosure, the term "lug" shall be
understood
to include both male lugs and female lugs. Thus, discussion of "lugs" engaging
one another
shall be understood to include complementary male and female lugs engaging one
another,
two or more male lugs engaging one another, as well as two or more female lugs
engaging
one another. Similarly, discussions of flexible beams engaging lugs shall be
understood to
include engagement of male or female lugs by a flexible beam.
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[0025] For the purposes of the present disclosure, the term "depth," when
referring
to lugs, shall be understood to be a measure of the change in vertical length
between a first
end and a second of a lug. As such, with regard to a female lug, the term
"depth" shall be
understood to be a measure of the trough created by second end of the lug.
Similarly, with
regard to a male lug, the term "depth" shall be understood to be a measure of
the peak created
by the second end of the lug. The term "depth" has been selected because in
the
embodiments shown, shoulder lugs of the outer cap are male and extend in a
downward
direction, where they mate with female shoulder lugs of the inner cap.
However, the term
"depth" is not limited to such male-to-female engagements nor to the relative
directions
depicted in the figures.
[0026] The present invention may be constructed of any one of a number of
polyolefins, including but not limited to polypropylene, as well as high-,
medium-, and low-
density polyethylene. These materials are known for their critical mechanical
properties
including, but not limited to, their flexural modulus, tensile strength, and
elongation, and with
the benefit of the present disclosure, one of ordinary skill in the art would
understand that
other materials exhibiting the same properties could be used in the
construction of the cap,
and therefore the invention is not limited to embodiments constructed of the
materials listed
above, but is intended to include all materials, whether presently known or
developed in the
future, which may exhibit similar structural properties.
[0027] Turning now to Figure 1, it can be seen that the child-resistant
cap 100 is of a
two-part construction, with an outer cap 101 and an inner cap 102. As can be
seen in Figure
2C, outer cap 101 has a top portion 103 which is adjacent to depending skirt
104. As shown
in Figure 2B, in one embodiment, depending skirt 104 contains a gripping
surface 105, which
may be defined by ridges, dimples, cross-hatching, or any other mechanism or
method known
to one skilled in the art to increase the friction between the hand of a user
and outer cap 104.
However, although the embodiment depicted in Figure 2B includes gripping
surface 105
embodied in the form of ridges, the invention is not so limited, and it is
contemplated that in
alternative embodiments, the materials used in the construction of outer cap
101 will provide
adequate friction and gripping capabilities for a user, and thus no
independent gripping
surface 105 may be present.
100281 Turning to Figures 2A and 2C, outer cap 101 also has an internal
chamber
106 defined by the interior surfaces of top portion 103 and depending skirt
104. The shape of
internal chamber 106 includes shoulder 107, on which is mounted a quantity of
shoulder lugs
108. Shoulder lugs 108 have a first end 109 and a second end 110. The depth of
shoulder
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lugs 108 increases from first end 109 to second end 110. The depth of shoulder
lugs 108 may
be varied to suit the specific needs of the enclosure, and with the benefit of
the present
disclosure, one skilled in the art would be enabled to tailor the depth of
shoulder lugs
appropriately. In one embodiment, the depth of shoulder lugs 108 ranges from
between
0.015 to 0.040 inches, although the present invention is not limited to this
embodiment.
Second end 110 has a lug face 111, oriented perpendicular to the longitude of
shoulder lug
108 and distal to first end 109. Further, the orientation of each lug face 111
is Common,
providing for a common rotational direction. That is to say, when each lug
face 111 is acted
upon by another object, the direction of action provides for a consistent
rotational action
around a central axis. In an alternative embodiment, second end 110 also
includes a bottom
surface extending parallel to the longitude of shoulder lug 108 and providing
for a ninety-
degree or "right angle" transition from second end 110 to lug face 111.
[0029] Internal chamber 106 is further defined by an annular ridge 112
located at a
predetermined distance from shoulder 107. The distance between shoulder 107
and annular
ridge 112 is greater than the height of shoulder lugs 108, and with the
benefit of the present
disclosure, one skilled in the art would be enabled to tailor the distance
between shoulder 107
and annular ridge 112 as required for the size and shape of the bottle and
closure in question.
In one embodiment, this may range from 0.562 to 0.576 inches, although the
present
invention is not limited to this embodiment.
[0030] Annular ridge 112 contains a quantity of skirt lugs 113. As with
shoulder
lugs 108, skirt lugs 113 have a first end 114 and a second end 115, with
second end 115
having a lug face 116. Lug faces 116 are oriented perpendicular to the
longitude of skirt lug
113 and distal to first end 114. Further the orientation of each lug face 116
is common, such
that when each lug face 116 is acted upon by another object, a common
rotational direction is
achieved, providing for rotation about a central axis. However, the
orientations of lug faces
116 is opposite that of the orientations of lug faces 111. That is to say, if
a clockwise
application of force is required to act upon and engage lug faces 111, the
opposite, counter-
clockwise application of force is required to act upon and engage lug faces
116, and vice
versa. Second end 115 also has bottom surface 117, oriented distal to top
portion 1103.
100311 Outer cap 101 also includes an assembly retaining bead 130 located
within
internal chamber 106 at a location distal to both shoulder 107 and annular
ridge 112. In one
embodiment, assembly retaining bead 130 is located a distance inward from open
end 131 of
outer cap 101. In an alternative embodiment, assembly retaining bead 130 is
located at open
end 131.
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[0032] Outer cap 101 is capable of vertical movement relative to inner cap
102. In
one embodiment depicted by the figures, the vertical downward travel distance
of outer cap
101 relative to inner cap 102 is 0.067 inches, although the present invention
is not so limited.
Indeed, with the benefit of this disclosure, one skilled in the art would be
enabled to
determine the appropriate downward travel for bottles of varying sizes, as may
be required by
product specifications set forth by the manufacturer.
(00331 As shown in Figures 3A-3C, inner cap 102 has a top portion 118, a
shoulder
119, a depending skirt 124, and an open end 132. As can be seen in Figure 3B,
Shoulder 119
is located at the transition point between top portion 118 and depending skirt
124. Figure 3A
depicts a quantity of shoulder lugs 120 mounted on shoulder 119. Shoulder lugs
120 have a
first end 121 and a second end 122. Second end 122 has a lug face 123 located
distal to first
end 121 and oriented perpendicular to the longitude of shoulder lugs 120. The
orientation of
lug faces 123 is common, such that when each lug is acted upon by another
object, common
rotational direction is achieved, providing for rotation about a central axis.
The orientation of
lug faces 111 is complementary to the orientation of lug faces 123 to provide
for engagement
of one lug face by the opposing lug face. In one embodiment, the depth of
shoulder lugs 120
ranges from between 0.015 to 0.040 inches, although the present invention is
not limited to
this embodiment.
[00341 Turning to Figure 3B, depending skirt 124 has a quantity of
flexible beams
125 mounted thereon. Flexible beams 125 extend around portions of the
perimeter of
depending skirt 124. Each flexible beam 125 consists of a beam base 126 and a
beam arm
127. Beam arm 127 has an angled ridge 128 which terminates in a beam head 129.
Beam
base 126 has an upper face 133 and a leading face 134. Angled ridge 128 has a
top side 135
and an underside 136. Angled ridge 128 is connected to beam base 126 such that
top side
135 extends from upper face 133 and underside 136 extends from leading face
134.
Underside 136 extends from leading face 134 in an arcuate or radiused manner.
When
downward force is exerted upon flexible beam 125, flexion or deformation takes
place along
angled ridge 128. The construction of flexible beam 125 is such that it has a
resiliency which
permits for it to return to its original shape and location when the downward
force is no
longer applied. In one embodiment, as pictured in Figures 3A-3C, underside 136
consists of
an arcuate or radiused portion 137 adjacent to a straight portion 138. In an
alternative
embodiment not shown, underside 136 consists entirely of an arcuate or
radiused portion 137.
Beam head 129 has an upper surface 139 and a beam face 140. In one embodiment,
the
radius of arcuate or radiused portion 137 is 0.065 inches, although the
invention is not so
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limited. With the benefit of the present specification, one skilled in the art
would understand
that any radius up to and including a radius of 0.095 inches could be
utilized. Indeed, as the
materials used in the construction of flexible beam 125 vary, different radii
may be necessary
to provide for maximum resiliency of flexible beam 125 while at the same time
ensuring that
downward forces exerted upon flexible beam 125 do not result in the
deformation of flexible
beam 125 in a vector oriented radially to a central axis.
[0035] Beam faces 140 are located distal to beam base 126 and have an
orientation
permitting for a common rotational direction about a central axis, such that
force imparted on
any beam face 140 will result in inner cap 102 rotating in the same direction
about a central
axis. The orientation of beam faces 140 is complementary to the orientation of
lug face 116,
and correspondingly the common rotational direction of beam faces 140 is
complementary to
the common rotational direction of lug faces 116.
[0036] The quantity of shoulder lugs 108 must be equivalent to the
quantity of
shoulder lugs 120. Additionally, the quantity of skirt lugs 113 must be
equivalent to the
quantity of flexible beams 125. Equivalent quantities provide for maximum
engagement of
lugs and complementary lugs and/or beams. Additionally, equivalent quantities
of shoulder
lugs 108, shoulder lugs 120, skirt lugs 113, and flexible beams 125 provide
for maximal
engagement of outer cap 101 with inner cap 102. As such, in one embodiment,
the quantity
of shoulder lugs 108 is equal to the quantity of shoulder lugs 120 and the
quantity of skirt
lugs 113 is equal to the quantity of flexible beams 125. In an alternative
embodiment, the
quantities of shoulder lugs 108, shoulder lugs 120, skirt lugs 113, and
flexible beams 125
are all equal. Traditional closure mechanisms have permitted unequal numbers
of
complementary lugs and or beams; such as six lugs designed to be complementary
mates to
eight fingers. These unequal quantities result in an increased chance of
slippage between
beams and lugs, and such slippage can result in damage to the flexible beams
themselves,
including permanent upward or downward deformation of the beams or crushing of
the
lugs, leading to a decrease in, or even full elimination of, the child-
resistant nature of the
two-part closure.
[0037] As can be seen in Figure 3C, inner cap also has an internal cavity
141 defined
by the internal surfaces of top portion 118, shoulder 119, and depending skirt
124. The
internal surface of depending skirt 124 is configured with threads 142 to
permit attachment of
the cap to a pre-existing bottle with complementary, mated threads on its neck
face.
[0038] In one embodiment, top portions 103 and 118, are flat and do not
extend
above shoulder 107 and 119 respectively.
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[0039] Figures 4A-4B depict cap 100 when it is attached to a pre-existing
bottle.
Figure 4A shows the outer view of cap 100 when it is attached to a pre-
existing bottle.
Figure 4B shows a cross-sectional view of cap 100 attached to a bottle, with
top portions 103
and 118 extending above and away from shoulder 107 and shoulder 119
respectively. In the
depicted embodiment, top portions 103 and 118 have a shape which is
complementary to the
shape of a dispenser nozzle for liquid medicaments. This complementary shape
provides for
an extra level of safety with regard to access of the medicament by a child.
In embodiments
with flat top portions 103 and 118, when cap 100 is affixed to a bottle of
liquid medicaments
and the bottle is inverted, there is the potential for liquid to flow out of
the bottle and pool
within the area created by the internal cavity of inner cap 102. Embodiments
containing such
an extruded shape complementary to the shape of a nozzle of a dispenser of
liquid
medicaments significantly reduce the overall volume of the cap cavity by more
closely
approximating the size and shape of the dispenser nozzle. By providing for a
smaller cavity
where medicaments may inadvertently pool, the embodiment depicted in the
Figures reduces
the likelihood of accidental overdose by children who ingest residual
medicament from a cap
which has been removed from the dispenser.
[0040] Another feature of the present invention involves the spatial
relationship of
shoulder lugs 108 and 120 as they relate to skirt lugs 113 and flexible beams
125. Figure 5
demonstrates the overlap exhibited by skirt lugs 113 and flexible beam 125
when lug faces
111 and 123 are aligned. In one embodiment, the overlap is a predetermined
horizontal
distance of 0.019 inches, although the present invention is not so limited,
and alternative
embodiments include overlaps in a variety of ranges. For example, in an
alternative
embodiment, the range for predetermined horizontal distances of overlap is
between 0.016
and 0.022 inches. In yet another alternative embodiment, the range for overlap
distance as
between 0.013 and 0.025 inches. With the benefit of the present disclosure,
one skilled in the
art would be enabled to create a closure with an overlap appropriate to any
size of cap as may
be required by production specifications.
[0041] An additional benefit of the present invention relates to the
interaction
between shoulder lugs 108, flexible beams 125, and assembly retaining bead
130. As
discussed above, flexible beams 125 have a resiliency which allow them to be
deformed
when a downward force is applied and then return to their original shape and
location when
the downward force is removed. This resiliency provides an upwards biasing
force on
shoulder lugs 108. This upward biasing force is counteracted by assembly
retaining bead
130, in that assembly retaining bead 130 prevents the upward biasing force
exerted on
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shoulder lugs 108 by flexible beams 125 from detaching outer cap 101 from
inner cap 102
entirely. As seen in Figures 6A-6C, when outer cap 101 is rotated relative to
inner cap 103 in
the direction required for removal of cap 100 from a bottle, most commonly in
the counter-
clockwise direction, skirt lugs 113 will come in contact with flexible beam
125. Figure 6A
shows skirt lug 113 first coming into contact with flexible beam 125. Figure
6B
demonstrates the result when the rotational direction of outer cap 101
continues with skirt
lugs 113 riding along angled ridge 128. If no downward force is applied to
outer cap 101, the
incline of angled ridge 128 will cause outer cap 101 to rise vertically with
respect to inner cap
102 until assembly retaining bead 130 engages inner cap 102, thus preventing
any further
vertical movement of outer cap 101 relative to inner cap 102. When assembly
retaining bead
130 has engaged inner cap 102, despite the vertical movement of outer cap 101
relative to
inner cap 102, bottom surface 117 of skirt lug 113 remains in contact with
beam head 129 of
flexible beam 125. As such, at not time does bottom surface 117 extend above
beam head
129 in such a manner as to provide unencumbered rotation of outer cap 101.
Instead, even
when the vertical distance between outer cap 101 and inner cap 102 is at its
greatest, there is
still a frictional force between bottom surface 117 and beam head 129. As a
result, outer cap
101 rises and falls vertically with respect to inner cap 102, in a ratcheting
motion when it is
rotated in this manner.
[0042] As has been described above, if no downward force is exerted upon
outer cap
101, it will rise vertically with respect to inner cap 102 when rotated in the
direction of
removal. This is shown in Figure 6C. Additionally, if no downward force has
been exerted
upon outer cap 101, when it has been rotated to align lug face 111 with lug
face 123 of inner
cap, outer cap 101 will be at its furthest possible vertical distance from
inner cap 101,
although, as has been described, the two caps remain in contact with one
another due to the
effects of assembly retaining bead 130 engage inner cap 102. However, when in
this aligned
position, lug face 111 has not yet engaged lug face 123, due to the vertical
differential
between the two caps. When a downward force is applied to outer cap 101 as
shown in
Figure 7, this vertical differential is decreased, and lug face 111 may
finally engage lug face
123. This downward force deforms or flexes each flexible beam 125, however
this
downward force is halted when shoulder lug 108 is fully nested in and engaged
with shoulder
lug 120. Further, this downward force acts upon beam head 129 and causes it to
change
position. However, the relationship of the depth of the shoulder lugs and the
displacement of
the beam head is such that when shoulder lugs 108 have fully engaged and
nested in shoulder
lug 120, that is to say, when it is no longer possible for outer cap 101 to
move any further
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downward relative to inner cap 101, beam head 129 is at its lowest position.
This position is
the optimal deformation of flexible beam 125, does not travel below the bottom
of the
adjacent beam base 126. Further, this downward force deforms or flexes angled
ridge 128
such that angled ridge becomes approximately parallel with the adjacent beam
base 126 when
beam head 129 is at its lowest position. By limiting the distance which beam
head 129
travels, hyper-flexion of flexible beam 125 can be prevented. This is
advantageous, because
hyper-flexion can result in a loss of resilience of flexible beam 125. When
resilience is lost,
an active downward force is no longer required to engage lug face 111 of
shoulder lug 108
with lug face 123 of shoulder lug 120. When the downward force is no longer
required, the
cap has lost its child-resistant nature. Therefore, the design of the present
invention
represents an improvement upon prior art, in that it eliminates hyper-flexion,
and thus
preserves the child-resistant nature of the cap; while the prior art, lacking
such a defined
spatial limitation on flexion, permits hyper-flexion and its resultant damage
to flexible beam
125 and loss of child-resistant functionality.
METHOD OF USE
[0043] The closure described above is designed to be applied to pre-
existing bottles
for liquid medicaments. It is understood that these bottles will already have
threads provided
on their neck finishes.
[0044] Application of the cap to the pre-existing bottle is effected
thusly: a
rotational movement is applied to outer cap 101 in an attaching direction
about a central axis
and relative to inner cap 102, the direction most commonly being clockwise,
until lug face
116 engages beam face 129, as shown in Figure 8. Once lug face 116 has engaged
beam face
140, the rotational movement is maintained on outer cap 101. This force is
then transferred
to inner cap 102, permitting the two caps to rotate in concert about a central
shared axis. This
rotation of inner cap 102 allows threads 142 to engage the threads of the pre-
existing bottle.
Rotation is maintained until threads 142 have fully engaged the threads of the
pre-existing
bottle. At this point, rotation ceases, and cap 100 has been affixed to the
pre-existing bottle.
As a result, no additional downward force is required to apply cap 100 to the
pre-existing
bottle. The engagement of threads 142 with the threads of the pre-existing
bottle will impart
a downward force on the cap 100 and cause it to travel downwards relative to
the pre-existing
bottle. However, this downward force is the mechanical result of the
engagement of threads
142 and is not imparted directly by the user. This represents a benefit over
the prior art in
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that present machinery which is only capable of imparting a rotational
direction may be used
to affix cap 100 to a bottle ¨ there is no re-tooling of the machine
necessary. Additionally,
machines imparting a downward force require careful calibration which can
often be thrown
out of alignment over the course of time. In such cases, caps may be
insufficiently applied to
a bottle, or more importantly, may be over tightened, causing damage to
flexible beam 125,
more specifically beam head 129. Prior art methods of affixing a child-
resistant to a cap
containing flexible beams 125 have often required a downward force, which
could potentially
crush beam head 129 or result in an increase in the depth of shoulder lugs 108
and 120.
Crushed beam heads 129 prevent the proper upward biasing of outer cap 101.
[0045] Removal of the cap is effected thusly: a downward force is applied
upon
outer cap 101, moving it in a downward direction relative to inner cap 102. A
rotational
movement is then applied to outer cap 101 in a removal direction about a
central axis relative
to inner cap 102, the direction most commonly being counter-clockwise.
Rotation of outer
cap 101 is continued until shoulder lugs 108 engage shoulder lugs 120.
Rotation of outer cap
101 continues, and the rotational force is transferred to inner cap 101 due to
the engagement
of shoulder lugs 108 with shoulder lugs 120. This continued rotation permits
outer cap 101
and inner cap 102 to rotate in concert about a central axis. This rotation of
inner cap 102
begins to disengage threads 142 from the threads of the pre-existing bottle.
Once the initial
torque needed to overcome the static frictional forces between threads 142 and
the threads of
the pre-existing bottle has been achieved, the user may optionally cease
applying a downward
force on outer cap 101. This option is available to the user because the
flexible beam 125
will impart an upward biasing force on outer cap 101; at the same time, the
placement of
assembly retaining bead 130 will maintain contact between bottom surface 117
of skirt lugs
113 and the angled ridge 128 and beam head 129 of flexible beam 125. This
contact results
in friction which continues to transfer the rotational force imparted on outer
cap 101 to inner
cap 102. Thus, maintained rotation of outer cap 101 will result in concerted
rotation of inner
cap 102 despite the fact that shoulder lugs 108 may no longer be engaging
shoulder lugs 120.
The rotational force continues to be applied to outer cap 101 and transferred
to inner cap 101
until threads 142 are fully disengaged from the threads of the pre-existing
bottle. At this
point the cap may be lifted from the pre-existing bottle. The method described
above is
particularly advantageous for the elderly, as it only requires the downward
force to be applied
until the torque needed to overcome the static frictional forces between
threads 142 and the
threads of the bottle has been overcome; it requires the two-directional
movement necessary
to ensure child-resistance, but by permitting only single-directional movement
at later stages
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of removal, ease of use is increased for those who have decreased coordination
or strength
due to advanced age and infirmity.
[00461 In an alternate embodiment, the first step of applying a downward
force and
the second step of applying a rotational force may be reversed, such that the
rotational force
is applied first and the downward force is applied second. In yet another
alternative
embodiment, the first two steps of applying a downward force and applying a
rotational force
are combined into a single step wherein the downward and rotational forces are
applied
simultaneously.
[00471 While the foregoing specification has been described with regard
to certain
preferred embodiments, and many details have been set forth for the purpose of
illustration, it
will be apparent to those skilled in the art without departing from the spirit
and scope of the
invention, that the invention may be subject to various modifications and
additional
embodiments, and that certain of the details described herein can be varied
considerably
without departing from the basic principles of the invention. Such
modifications and
additional embodiments are also intended to fall within the scope of the
appended claims.
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