U.S. patent number RE45,665 [Application Number 11/700,903] was granted by the patent office on 2015-09-08 for flow control element including elastic membrane with pinholes.
This patent grant is currently assigned to Medela Holding AG. The grantee listed for this patent is James W. Holley. Invention is credited to James W. Holley.
United States Patent |
RE45,665 |
Holley |
September 8, 2015 |
Flow control element including elastic membrane with pinholes
Abstract
A flow control element (e.g., a baby bottle nipple or a child
nippy cup flow control valve) that includes a tube-like wall
section defining a flow channel, and a substantially flat membrane
supported by the wall section such that membrane impedes flow
through the flow channel to an external region. The membrane
punctured to form multiple, substantially round pinholes arranged
in a two-dimensional pattern that remain closed to prevent fluid
flow under normal atmospheric conditions, and open and to
facilitate fluid flow rate through the membrane under an applied
pressure differential (e.g., when sucked on by a child). The wall
section has a greater rigidity than the membrane (which is formed
from a relatively highly elastic material). Different sized
pinholes are produced using different sized pins, thereby
facilitating different flow rates in response to different applied
pressure differentials. The pinholes are generated while stretching
the membrane in a radial direction.
Inventors: |
Holley; James W. (Colorado
Springs, CO) |
Applicant: |
Name |
City |
State |
Country |
Type |
Holley; James W. |
Colorado Springs |
CO |
US |
|
|
Assignee: |
Medela Holding AG (Baar,
CH)
|
Family
ID: |
32735734 |
Appl.
No.: |
11/700,903 |
Filed: |
January 31, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
10351137 |
Jan 24, 2003 |
6957744 |
|
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Reissue of: |
10758573 |
Jan 13, 2004 |
6991122 |
Jan 31, 2006 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61J
11/009 (20130101); A61J 11/001 (20130101); B26F
1/24 (20130101); B65D 47/20 (20130101); A61J
9/00 (20130101) |
Current International
Class: |
A61J
11/00 (20060101); B65D 47/20 (20060101); B26F
1/24 (20060101) |
Field of
Search: |
;215/11.1,11.4,11.5,902,247,248,262,311,385
;220/711,714,203.11-203.19,366.1,367.1 ;30/368
;137/512.15,587,588,849 ;251/149.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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3830448 |
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Mar 1990 |
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DE |
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571788 |
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May 1924 |
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FR |
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2302724 |
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Oct 1976 |
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FR |
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2154451 |
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Sep 1985 |
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GB |
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WO 9203118 |
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Mar 1992 |
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WO |
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9911218 |
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Mar 1999 |
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WO |
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WO 9929278 |
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Jun 1999 |
|
WO |
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WO 03045200 |
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Jun 2003 |
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WO |
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Primary Examiner: Weaver; Sue A
Attorney, Agent or Firm: McDonnell Boehnen Hulbert &
Berghoff LLP
Parent Case Text
RELATED APPLICATION
The present application is a continuation-in-part of U.S. patent
application Ser. No. 10/351,137 filed by James W. Holley, Jr. on
Jan. 24, 2003 .Iadd.now U.S. Pat. No. 6,957,744.Iaddend..
Claims
What is claimed is:
1. A flow control element for controlling the flow of a liquid
.Iadd.between a first region and a second region of a wall
section.Iaddend., the flow control element comprising: .[.a
tube-like wall section having a first end and a second end, the
wall section defining a liquid flow channel extending from the
first end to the second end of the wall section; and.]. a
substantially flat.Iadd., elastic .Iaddend.membrane .Iadd.including
a perimeter, wherein the perimeter of the membrane is
.Iaddend.connected to the wall section such that the membrane is
disposed between .Iadd.the first region and the second region in
the flow path of .Iaddend.the liquid .[.flow channel and an
external region located outside of the flow control element.].,
wherein the membrane defines a plurality of pinholes that are
formed such that when the membrane is subjected to normal
atmospheric conditions and the membrane remains undeformed, the
plurality of pinholes remain closed to prevent liquid flow between
the .[.liquid flow channel.]. .Iadd.first region .Iaddend.and the
.[.external.]. .Iadd.second .Iaddend.region through the membrane,
and when the membrane is deformed in response to an applied
pressure differential between the .[.liquid flow channel.].
.Iadd.first region .Iaddend.and the .[.external.]. .Iadd.second
.Iaddend.region, the plurality of pinholes open to facilitate
.[.liquid.]. flow .Iadd.of said liquid .Iaddend.through the
membrane.
2. The flow control element according to claim 1, wherein the wall
section defines a central axis, and wherein the membrane is
.[.and.]. arranged perpendicular to the central axis.
3. The flow control element according to claim 1, wherein the
plurality of pinholes are arranged in a two-dimensional
pattern.
4. The flow control element according to claim .[.1.].
.Iadd.2.Iaddend., wherein the wall section has a greater rigidity
than the membrane such that, when an applied pressure differential
is generated between the .[.liquid flow channel.]. .Iadd.first
region .Iaddend.and the .[.external.]. .Iadd.second
.Iaddend.region, the membrane undergoes a greater deformation than
the wall section.
5. The flow control element according to claim 4, wherein the
membrane and the wall section form an integrally molded structure
comprising at least one of silicone, a thermoplastic elastomer, and
soft rubber, and wherein the wall section has a first thickness
that is greater than a second thickness of the membrane.
6. The flow control element according to claim 4, wherein the wall
section is formed from a .[.first,.]. relatively rigid material.[.,
and wherein the membrane is formed from a second, relatively
elastic material.]..
7. The flow control element according to claim 1, wherein the flow
control element comprises a nipple for a baby bottle.
8. The flow control element according to claim 1, wherein the flow
control element comprises a valve for a sippy cup.
9. A flow control element for controlling the flow of a liquid
.Iadd.between a first region and a second region of a wall
section.Iaddend., the flow control element comprising: .[.a
tube-like wall section having a first end and a second end, the
wall section defining a liquid flow channel extending from the
first end to the second end of the wall section; and.]. a
substantially flat.Iadd., elastic .Iaddend.membrane .Iadd.including
a perimeter, wherein the perimeter of the membrane is
.Iaddend.connected to the wall section such that the membrane is
disposed between .[.the liquid flow channel and an external region
located outside of the flow control element.]. .Iadd.the first
region and the second region.Iaddend., wherein the membrane defines
a plurality of pinholes that are formed such that when the membrane
is subjected to normal atmospheric conditions and the membrane
remains undeformed, the plurality of pinholes remain closed to
prevent liquid flow between the .[.liquid flow channel.].
.Iadd.first region .Iaddend.and the .[.external.]. .Iadd.second
.Iaddend.region through the membrane, and when the membrane is
deformed in response to an applied pressure differential between
the .[.liquid flow channel.]. .Iadd.first region .Iaddend.and the
.[.external.]. .Iadd.second .Iaddend.region, the plurality of
pinholes open to facilitate liquid flow through the membrane, and
wherein the plurality of pinholes include a first pinhole and a
second pinhole that are formed such that when the membrane is
subjected to a first, relatively low applied pressure differential,
the first pinhole remains closed and the second pinhole opens to
facilitate a first, relatively low liquid flow rate through the
membrane, and when the membrane is subjected to a second,
relatively high applied pressure differential, both the first
pinhole and the second pinhole open to facilitate a second,
relatively high liquid flow rate through the membrane.
10. A flow control element for controlling the flow of a liquid,
the flow control element comprising: a wall section surrounding a
liquid flow channel; and a substantially flat elastic membrane
connected to the wall section and extending across the liquid flow
channel, wherein the elastic membrane defines a plurality of first
pinholes and a plurality of second pinholes, wherein said
pluralities of first pinholes and second pinholes are formed such
that: when the membrane is subjected to normal atmospheric
conditions, both the first pinholes and the second pinholes remain
closed to prevent liquid flow from the liquid flow channel through
the membrane, when the membrane is subjected to a first, relatively
low applied pressure differential, the first pinholes remain closed
and the second pinholes open to facilitate a first, relatively low
liquid flow rate through the membrane, and when the membrane is
subjected to a second, relatively high applied pressure
differential, both the first pinholes and the second pinholes open
to facilitate a second, relatively high liquid flow rate through
the membrane.
11. The flow control element according to claim 10, wherein the
wall section defines a .Iadd.longitudinal .Iaddend.central axis,
and wherein the elastic membrane is .[.and.]. arranged
perpendicular to the central axis.
12. The flow control element according to claim 10, wherein the
first and second pinholes are arranged in a two-dimensional
pattern.
13. The flow control element according to claim 10, wherein the
wall section has a greater rigidity than the elastic membrane such
that, when an applied pressure differential is generated between
the liquid flow channel and an external region, the membrane
undergoes a greater deformation than the wall section.
14. The flow control element according to claim 13, wherein the
membrane and the wall section form an integrally molded structure
comprising at least one of silicone, a thermoplastic elastomer, and
soft rubber, and wherein the wall section has a first thickness
that is greater than a second thickness of the membrane.
15. The flow control element according to claim 13, wherein the
wall section is formed from a first, relatively rigid material, and
wherein the membrane is formed from a second, relatively elastic
material.
16. The flow control element according to claim 10, wherein the
flow control element comprises a nipple for a baby bottle.
17. The flow control element according to claim 10, wherein the
flow control element comprises a valve for a sippy cup.
18. A method for manufacturing a flow control element, the flow
control element including a tube-like wall section surrounding a
fluid flow channel, and an elastic membrane .Iadd.defining a radial
axis, the membrane being .Iaddend.integrally formed with the wall
section .[.and extending across the fluid flow channel.]., the
method comprising: stretching the elastic membrane by applying a
tensile force along the radial axis; piercing the stretched elastic
membrane using a plurality of pins, thereby forming a plurality of
pinholes; and removing the plurality of pins and releasing the
tensile force, whereby each of the plurality of pinholes is closed
by elastomeric material surrounding said each pinhole and the
elastic membrane is subjected to normal atmospheric conditions,
wherein piercing comprises inserting a first pin having a first
diameter into the stretched elastic membrane to form a first
pinhole, and inserting a second pin having a second diameter into
the stretched elastic membrane to form a second pinhole, wherein
the first diameter is smaller than the second diameter.
Description
FIELD OF THE INVENTION
The present invention relates to fluid flow control devices for
beverage containers, and more specifically it relates to "no drip"
flow control elements for baby bottles and child sippy cups.
RELATED ART
Baby bottles and sippy cups represent two types of beverage
containers that utilize flow control devices to control the
ingestion of beverage in response to an applied sucking force. Baby
bottle assemblies utilize nipples to pass baby formula or milk from
the bottle to a child (i.e., infant or toddler) in response to a
sucking force (pressure) applied by the child on the nipple. Sippy
cups are a type of spill-resistant container typically made for
children that include a cup body and a screw-on or snap-on lid
having a drinking spout molded thereon. An inexpensive flow control
element, such as a soft rubber or silicone outlet valve, is often
provided on the sippy cup lid to control the flow of liquid through
the drinking spout and to prevent leakage when the sippy cup is
tipped over when not in use.
A problem associated with conventional baby bottle nipples is that,
unlike natural female breasts, the quantity of formula/milk drawn
through the nipple is relatively fixed, which causes a parent to
periodically replace relatively low flow nipples with higher flow
nipples as a child's feeding needs increase. Natural breasts
generally adjust to a baby's sucking pressure so that its
nutritional needs are met as it grows. When newborn, an infant's
sucking force is relatively weak and its appetite is relatively
small, so the female breast supplies a relatively low flow rate. As
the infant grows into a toddler, its sucking force increases along
with its appetite. Female breasts are able to adjust to this
increased demand by providing a higher flow rate in response to the
increased sucking force and appetite. Unlike breast-fed babies,
bottle-fed babies often experience feeding related problems
associated with conventional nipple products that exhibit
substantially fixed milk flow rates. That is, many conventional
nipples are provided with an opening that is sized to facilitate a
relatively fixed amount of milk flow depending on the size of the
baby. Nipples for newborn babies have relative small holes that
support relatively low flow rates, while nipples for toddlers
typically include relatively large holes or slits to facilitate
greater flow rates. A problem arises when a baby's draw rate fails
to match the particular nipple from which that baby is being fed.
For example, when a newborn infant is fed from a toddler nipple,
the high flow rate can result in choking and coughing. Conversely,
when a toddler is presented with a newborn baby's nipple, the low
flow rate can cause frustration. In many instances, parents
experience a great deal of anxiety trying to match the correct
nipple to a baby's ever-changing milk flow demand.
A problem associated with "no drip" flow control elements (i.e.,
sippy cup flow control valves and baby bottle nipples) that are
formed by cutting or molding slits in elastomeric material is that
these slits typically fail or become clogged over time, which
results in undesirable leakage and/or failure. Such sippy cup flow
control valves typically include a sheet of the elastomeric
material located between the inner cup chamber and the drinking
spout that defines one or more slits formed in an X or Y pattern.
As a child tilts the container and sucks liquid through the
drinking spout, the slits yield and the flaps thereof bend outward,
thereby permitting the passage of liquid to the child. When the
child stops sucking, the resilience of the causes the slits to
close once more so that were the cup to be tipped over or to fall
on the floor, no appreciable liquid would pass out the drinking
spout. Similarly, some toddler nipples are formed by cutting or
molding slits into the end of a silicone nipple that yield and open
outward to pass formula or milk when a toddler tilts the bottle and
applies a sucking force, and to close when the child stops sucking.
The problem with such slit-type sippy cup valves and baby bottle
nipples as is that the elastomeric material in the region of the
slits can fatigue and/or become obstructed over time, and the
resulting loss of resilience can cause leakage when the slit flaps
fail to fully close after use. This failure of the slit flaps to
close can be caused by any of several mechanisms, or a combination
thereof. First, repeated shearing forces exerted at the end of each
slit due to repeated use can cause tearing of the elastomeric
material in this region, thereby reducing the resilient forces
needed to close the slit flaps after use. Second, thermal cycling
or mechanical cleaning (brushing) of the elastomeric material due,
for example, to repeated washing, can cause the elastomeric
material to become less elastic (i.e., more brittle), which can
also reduce the resilience of the slit flaps. Third, solid deposits
left by liquids passing through the slits can accumulate over time
to impede the slit flaps from closing fully.
What is needed is a "no drip" flow control element for baby bottles
and the like that automatically adjusts its fluid flow rate to the
needs of a growing child. What is also needed is a flow control
element that avoids the clogging and tearing problems associated
with conventional slit-type elastic flow control elements.
SUMMARY
The present invention is directed to a flow control element (e.g.,
a baby bottle nipple or a child sippy cup flow control valve) that
includes a tube-like wall section defining a flow channel, and a
membrane supported in the flow channel such that membrane impedes
flow through the flow channel to an external region. The membrane
is formed from a suitable elastomeric material (e.g., soft rubber,
thermoplastic elastomer, or silicone) that is punctured to form
multiple, substantially round pinholes that remain closed to
prevent fluid flow through the membrane and flow channel under
normal atmospheric conditions (i.e., while the membrane remains
non-deformed), thereby providing a desired "no drip"
characteristic. In contrast, when subjected to an applied pressure
differential (e.g., when sucked on by a child), the membrane
stretches (deforms), thereby causing some or all of the pinholes to
open and to facilitate fluid flow rate through the membrane.
Because the amount that the pinholes open, and the associated fluid
flow through the pinholes, is related to the applied pressure
differential, the present invention provides a flow control element
that automatically adjusts its fluid flow rate to the needs of a
growing child. In addition, because the pinholes are substantially
round, the pinholes resist the clogging and tearing problems
associated with slit-type flow control elements.
According to an embodiment of the present invention, the membrane
is substantially flat (planar) and arranged such that a force
generated by the applied pressure differential is perpendicular to
a plane defined by the non-deformed membrane. By providing a flat
membrane, sufficient deformation of the membrane (and associated
opening of the pinholes) is achieved in response to a relatively
small sucking force (pressure). Formation of the pinholes is also
easier when the membrane is flat.
According to an aspect of the invention, the pinholes are arranged
in a spaced-apart, two-dimensional pattern (e.g., a diamond
pattern), thereby maintaining a relatively balanced pressure on the
membrane that resists tearing of the membrane material as a child's
sucking force increases.
According to another aspect of the present invention, the wall
section has a greater rigidity than the membrane (which is formed
from a relatively highly elastic material) such that, when an
applied pressure differential is generated between the fluid flow
channel and the external region, the membrane undergoes a greater
deformation than the wall section. This arrangement directs the
applied flow pressure against the membrane to produce maximum
deformation for a given applied sucking pressure.
According to another embodiment of the present invention, the
pinholes are formed such a first group of pinholes opens at a lower
applied pressure differential than a second group of pinholes,
which open at a somewhat higher applied pressure. Such different
sized pinholes produce relatively low flow rates at low sucking
pressures (i.e., because larger pinholes open while smaller
pinholes remain essentially closed), and substantially greater flow
rates at high sucking pressures (i.e., because both large and small
pinholes are opened), thereby facilitating the production of a baby
bottle nipple that can be used throughout a child growth from
infant to toddler.
According to another embodiment of the present invention, a flow
control element including the wall section and elastic membrane
described above is produced by stretching the elastic membrane in a
radial direction, piercing the membrane using a pin, and then
releasing the membrane such that the thus-produced pinhole closes.
In one embodiment, stretching is performed inserting a base
structure or other fixture into the wall section such that the wall
section is pushed radially outward, thereby stretching the
membrane. In another embodiment, two pins having different
diameters are used to form the pinholes.
The present invention will be more fully understood in view of the
following description and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective side view showing a flow control element
according to a generalized embodiment of the present invention;
FIGS. 2(A) and 2(B) are top and cross-sectional side views,
respectively, showing the flow control element of FIG. 1;
FIGS. 3(A) and 3(B) are simplified diagrams illustrating tensile
forces generated in flat and curved membranes;
FIGS. 4(A), 4(B) and 4(C) are enlarged cross-sectional side views
showing a portion of the membrane of the flow control element of
FIG. 1 during operation;
FIG. 5 is a simplified cross-sectional side view showing an
apparatus for forming pinholes in the flow control element of FIG.
1;
FIGS. 6(A), 6(B) and 6(C) are enlarged cross-sectional side views
showing the membrane portion of FIG. 1 during the formation of
pinholes using the apparatus of FIG. 5;
FIG. 7 is a partial cut-away side view showing a baby bottle
assembly utilizing a nipple according to an exemplary embodiment of
the present invention;
FIG. 8 is a cross-sectional side view showing the nipple used on
the baby bottle of FIG. 7;
FIG. 9 is a top plan view of the nipple shown in FIG. 8;
FIG. 10 is a top plan view showing a nipple according to another
exemplary embodiment of the present invention;
FIGS. 11(A) and 11(B) are cross-sectional side views of the nipple
shown in FIG. 10;
FIG. 12 is a side view showing a sippy cup including a flow control
element according to another exemplary embodiment of the present
invention;
FIG. 13 is a plan view showing the flow control element utilized in
the sippy cup of FIG. 12;
FIG. 14 is a cross-sectional side view taken along section line
14-14 of FIG. 13;
FIG. 15 is a side view showing a portion of a sippy cup including a
flow control element according to another exemplary embodiment of
the present invention;
FIG. 16 is a plan view showing the flow control element utilized in
the sippy cup of FIG. 15; and
FIG. 17 is a cross-sectional side view taken along section line
17-17 of FIG. 16.
DETAILED DESCRIPTION
FIG. 1 is a perspective view showing a generalized flow control
element 50 including a wall section 54 and a membrane 55. FIGS.
2(A) and 2(B) show flow control element 50 in top plan and
cross-sectional side views, respectively, where FIG. 2(B) is taken
along section line 2-2 of FIG. 2(A).
Wall section 54 is a tube-like structure defining a fluid flow
channel 56 that extends generally along a central axis X between a
lower (first) end 54A and an upper end 54B of wall section 54. As
indicated in FIG. 2(A), in one embodiment wall section 54 has a
circular cross section having a diameter D.
Membrane 55 is formed form a relatively elastic material and is
connected to wall section 54 such that membrane 55 is disposed
across fluid flow channel 56 to impede flow between fluid flow
channel 56 and an external region ER (i.e., either from fluid flow
channel 56 to external region ER, or from external region ER to
fluid flow channel 56). In the disclosed embodiment, membrane 55
has a circular outer perimeter 57 that is secured to wall section
54, elastic membrane 55 is formed from a suitable material (e.g.,
soft rubber, thermoplastic elastomer, or silicone) having a
thickness T2 in the range of 0.01 to 0.1 inches (more particularly,
0.02 to 0.05 inches). According to the present invention, membrane
55 defines a plurality of spaced-apart pinholes 58 and 59 formed
using the procedure describe below such that when the membrane is
subjected to normal atmospheric conditions and the membrane remains
non-deformed, pinholes 58 and 59 remain closed to prevent fluid
flow between fluid flow channel 56 and external region ER through
membrane 55. As described in additional detail below, pinholes 58
and 59 are also formed such that when membrane 55 is deformed
(stretched) in response to an applied pressure differential between
fluid flow channel 56 and external region ER, pinholes 58 and 59
open to facilitate fluid flow through membrane 55. Accordingly,
pinholes 58 and 59 facilitate adjustable fluid flow through
membrane 55 that increases in direct relation to the applied
pressure differential, thereby facilitating, for example, a baby
bottle nipple that can be used throughout a child's development
from infant to toddler.
As indicated in FIG. 2(B), according to a preferred embodiment of
the present invention, membrane 55 is substantially flat (planar)
in its relaxed (i.e., non-deformed or unstretched) state, and lies
in a plane X-Y that is perpendicular to central axis X defined by
wall section 54. Two advantages are provided by making membrane 55
in this manner. A first advantage, which is illustrated by the
simplified diagrams shown in FIGS. 3(A) and 3(B), is that a flat
membrane is easier to stretch under an applied pressure than a
curved membrane. In particular, as depicted in FIG. 3(A), a
pressure P.sub.z applied perpendicular to substantially flat
membrane 55 causes membrane 55 stretches (bows downward, as
indicated by the dashed membrane 55'). Note that because membrane
55 is substantially flat, virtually all of the resultant tensile
force T generated in membrane 55 is directed in the X-Y plane
(indicated by component T.sub.x-y), thereby generating little or no
component T.sub.z in the Z-axis direction until the membrane is at
least partially stretched. Because the tension component T.sub.z
remains relatively small, planar membrane 55 is stretched (and the
pinholes opened) in response to a relatively small applied pressure
P.sub.z, thereby facilitating fluid flow through membrane 55 in
response to a relatively small sucking force. In contrast, as
indicated in FIG. 3(B), a pre-curved membrane 310 generates a
significantly larger tensile force component T.sub.z, thereby
requiring a substantially larger pressure P.sub.z to produce even a
minimal stretching of membrane 310 from its resting position (e.g.,
as indicated by deformed membrane 310', shown in FIG. 3(B)). A
second advantage to provided by making membrane 55 substantially
flat is that, as described below, formation of the pinholes is
greatly simplified and facilitated.
Although the preferred embodiment includes a substantially flat
(planar) membrane, a curved membrane may also be used, although
such membrane would necessarily be relatively thin (i.e., relative
to a flat membrane formed from the same material) in order to
facilitate a similar amount of deformation in response to an
applied pressure. A problem posed by using a relatively thin
membrane is the increased chance of rupture and/or tearing of the
membrane material, which may result in the unintended ingestion of
membrane material.
Referring to FIG. 2(A), according to an aspect of the present
invention, membrane 55 defines a plurality of spaced-apart pinholes
58 and 59 that are arranged in a two-dimensional pattern. The term
"spaced-apart" is used to indicate that the pinholes are separated
by regions of non-perforated membrane material (i.e., there are no
holes, cracks, slits, or other significant structural weaknesses in
the membrane material in the regions separating adjacent pinholes).
The spacing between pinholes 58 and 59 is selected based on the
membrane material such that tearing of the membrane material
between adjacent pinholes is avoided under normal operating
conditions (i.e., the pinholes are spaced as far apart as is
practical). Note that arranging pinholes 58 and 59 in a
two-dimensional pattern provides the advantage of balancing the
distribution of forces across membrane 55, thereby reducing the
chance of tearing of the membrane material.
According to another aspect of the present invention, wall section
wall section 54 has a greater rigidity than the membrane 55 such
that, when an applied pressure differential is generated between
fluid flow channel 56 and external region ER, membrane 55 undergoes
a greater amount of deformation than wall section 54. In one
embodiment, membrane 55 and wall section 54 are integrally molded
from a suitable material (i.e., both hollow structure 54 and
elastic membrane 55 are molded in the same molding structure using
a single molding material, e.g., silicone, a thermoplastic
elastomer, or soft rubber), and the increased rigidity is provided
by forming wall section 54 to include a thickness T1 that is
greater than the thickness of membrane 55. In an alternative
embodiment, wall section 54 may be formed from a relatively rigid
material (e.g., a hard plastic), and membrane 55 may be separately
formed from a relatively elastic material and then secured to wall
member 54.
Referring again to FIGS. 1 and 2(A), membrane 55 is depicted as
being secured around its peripheral edge 57 to upper end 54B of
wall section 54. As set forth in at least one specific embodiment
provided below, membrane 55 may be alternatively be recessed into
flow channel 56 to avoid damage caused, for example, by gumming or
chewing on the end of flow control element 50. In yet other
alternative embodiments, membrane 55 may located anywhere between
lower end 54A and upper end 54B of wall section 54.
FIGS. 4(A) through 4(C) are enlarged cross-sectional side views
depicting pinholes 58 and 59 under normal atmospheric conditions
(FIG. 4(A)) and under applied pressure differential conditions
(FIGS. 4(B) and 4(C)). Referring to FIG. 4(A), under normal
atmospheric conditions (i.e., when a pressure PR1 exists both in
fluid flow channel 56 and in external region ER), membrane 55
remains non-deformed (e.g., planar), and pinholes 58 and 59 remain
closed to prevent fluid flow between fluid flow channel 56 and the
external region ER through membrane 55. In contrast, as indicated
in FIG. 4(B), when an applied pressure differential is generated
(e.g., pressure PR1 exists in fluid flow channel 56, but a
relatively low pressure PR2 is generated in external region ER,
e.g., due to sucking), membrane 55 is deformed (i.e., stretched
toward external region ER), and at least one of pinholes 58 and 59
is opened to facilitate fluid flow through membrane 55.
According to another embodiment of the present invention, pinholes
58 and 59 are formed, for example, using different sized pins (as
described below) such that when membrane 55 is subjected to a
relatively low applied pressure differential, pinholes 58 remain
closed and pinholes 59 open to facilitate a relatively low fluid
flow rate through membrane 55, and when membrane 55 is subjected to
a relatively high applied pressure differential, both pinholes 58
and 59 open to facilitate a relatively high fluid flow rate through
membrane 55. As indicated in FIG. 4(A), both holes 58 and 59 remain
pinched closed under normal atmospheric conditions due to the
elasticity of the membrane material. However, because holes 59 are
formed using a larger pin than that used to form holes 58, the
elastic closing force F.sub.58 that pinches closed hole 58 is
larger than the elastic closing force F.sub.59 pinching closed hole
59. Accordingly, as shown in FIG. 4(B), a relatively small pressure
differential deforms membrane 55' and overcomes the elastic closing
force F.sub.59 to open pinhole 59', but does not overcome the
elastic closing force F.sub.58 holding closed pinhole 58, thereby
producing a relatively low fluid flow through deformed membrane
55'. As shown in FIG. 4(C), when a relatively large pressure
differential is applied across membrane 55'' that overcomes both
elastic closing forces F.sub.58 and F.sub.59, both pinholes 58''
and 59'' open to producing a relatively high fluid flow through
deformed membrane 55''.
FIG. 5 is a simplified cross-sectional side view depicting an
apparatus for generating pinholes in flow control element 50, and
FIGS. 6(A) through 6(C) illustrate the process of forming the
pinholes in membrane 55 according to another embodiment of the
present invention.
Referring to FIG. 5, the apparatus includes a base structure 400
and a movable structure 405. Base structure 400 is shaped to fit
inside of control element 50 in a manner that stretches wall
section 54, thereby stretching elastic membrane 55 along its radial
direction (i.e., along the plane X-Y). In the disclosed embodiment,
base structure 400 has a diameter D400 that is 1% to 10% greater
than the diameter D of wall section 54 (see FIG. 2(A)).
Accordingly, as indicated in FIG. 6(A) when base structure 400 is
press-fitted into wall section 54 (as shown in FIG. 5), a tensile
force F is generated that stretches membrane 55 along plane X-Y
such that it expands by 1% to 10% of its resting diameter.
Referring again to FIG. 5, extending from a lower surface of
movable structure 405 are several pins 410 that are arranged in a
predetermined pattern corresponding to the desired two-dimensional
pinhole pattern (e.g., the diamond patter indicated in FIG. 2(A),
which is described above). During operation, movable structure 405
is reciprocated in the Z direction such that pins 410 pierce
membrane 55 to form pinholes. In a preferred embodiment, each pin
410-1 and pin 410-2 is formed with a continuously curved (e.g.,
circular) cross section such that each pinhole 158 and each pinhole
159 is substantially circular (i.e., does not have a slit or fold
that would be formed by a cutting element having an edge). In
addition, according to an embodiment of the present invention,
different sized pins 410-1 and 410-2 are utilized to produce
pinholes 58 and 59 in membrane 55. In particular, as indicated in
FIG. 6(A), each pin 410-1 has a relatively small diameter D1, and
each pin 410-2 has a relatively large diameter D2. As indicated in
FIG. 6(B) when pins 410-1 and 410-2 are inserted into membrane 55,
holes 58 and 59 are formed with diameters that correspond to the
diameters of pins 410-1 and 410-2, respectively. In one practical
embodiment, pins 410-1 having a diameter D1 of approximately 0.028
inches were used to produce pinholes 58 and pins 410-2 having a
diameter D2 of approximately 0.062 inches were used to produce
pinholes 59 (i.e., using a membrane 55 having a thickness of
approximately 0.02 inches). Subsequently, as indicated in FIG.
6(C), when pins 410-1 and 410-2 are subsequently removed from
membrane 55, flow control element is removed from the base
structure (i.e., the tensile force in membrane 55 is released), and
membrane 55 is subjected to normal atmospheric conditions, pinholes
58 and 59 are at least partially closed by the elastomeric membrane
material surrounding each pinhole (e.g., as indicated by forces
F.sub.58 and F.sub.59).
The present invention will now be described with reference to
certain specific embodiments, each of which includes a wall section
and elastic membrane formed according to the generalized embodiment
described above.
FIG. 7 is a partial cut-away side view showing a baby bottle
assembly 100 including a nipple (flow control element) 150 formed
in accordance with a first specific embodiment of the present
invention. Baby bottle assembly 100 generally includes a
substantially cylindrical bottle body 110 and a ring-shaped cap 140
for securing nipple 150 to bottle body 110. Bottle body 110 has a
roughly cylindrical wall 111 and threaded upper neck 113 that
define a beverage storage chamber 117 for storing a fluid beverage
(i.e., infant formula or milk). Cap 140 includes a cylindrical base
portion 142 having threaded inside surface, and a disk-shaped upper
portion 145 defining a central opening through which a portion of
nipple 150 extends. When cap 140 is connected (screwed) onto bottle
body 110, the threads formed on cylindrical base portion 142 mate
with threaded neck 113. Bottle body 110 and cap 140 are molded from
a suitable plastic using known methods.
Referring to FIGS. 8 and 9, nipple 150 includes a lower disk-shaped
flange 151, a lower conical wall section 152 extending upward from
flange 151, a neck region 153 formed above lower conical wall
section 152, an upper conical wall section 154 extending upward
from neck region 153, and a substantially flat, disk-shaped upper
membrane 155 located at the upper portion of upper conical wall
section 154. Lower conical wall section 152, neck region 153, upper
conical region 154, and membrane 155 define an interior chamber
157. As indicted in FIG. 1, when mounted in bottle assembly 100, a
ring-shaped portion of flange 151 is pinched between an upper edge
of neck 113 and a portion of upper portion 145 of cap 140, and
interior chamber 157 of nipple 150 communicates with storage
chamber 117 of bottle body 110. Lower conical wall section 152
extends through the opening defined in disk-shaped upper portion
145 of cap 140, and gradually tapers from a relatively wide
diameter near flange 151 to a relatively narrow diameter D2 at neck
region 153. Above neck region 153, upper conical wall section 154
again widens to a third, relatively wide diameter D3, which
corresponds with the diameter of disk-shaped upper membrane 155.
Flange 151 and conical sections 152 and 154 are formed using
relatively thick sections of the elastomeric material, in
comparison to membrane 155, which is relatively thin. In one
embodiment, nipple 150 is molded as a single integral piece using
silicone. In this embodiment, flange 151 has a thickness T3 of
approximately 0.1 inches and a diameter D3 of approximately 2
inches, lower conical wall section 154 has a thickness T4 of
approximately 0.06 inches, and membrane 155 has a diameter D4 of
approximately 0.75 inches and thickness of approximately 0.02
inches. As indicated in FIG. 8, during use (e.g., when an
infant/child sucks on nipple 150 with bottle body 110 tipped such
that liquid flows into nipple chamber 157), a pressure differential
is generated such that a relatively high pressure inside storage
chamber 117 becomes greater than a relatively low pressure in the
infant/child's mouth, thereby causing membrane 155' to stretch
upward from plane X-Y in the manner described above, thereby
opening at least some of pinholes 158 and 159 to facilitate
feeding.
FIGS. 10, 11(A) and 11(B) show a nipple 250 according to another
specific embodiment of the present invention. Nipple 250 includes a
lower flange 251, a lower wall section 252 extending upward from
flange 251, an oval neck structure 254 extending upward from lower
wall section 252, and an flat oval membrane 255 formed at an upper
edge of neck structure 254. The dimensions and thicknesses
associated with nipple 250 are similar to those described above
with reference to the first embodiment. Also, similar to the first
embodiment, membrane 255 is essentially flat such that it defines
plane X-Y. Note that, due to the smaller size of membrane 255
(i.e., approximately one-half inch along the short axis and
three-quarters of an inch along the long axis), the number of holes
258 formed therein is smaller (e.g., thirty-seven, with nineteen
larger pinholes 259 and eighteen smaller pinholes 258). To
compensate for the smaller number of pinholes, the membrane
thickness may be reduced (e.g., to 0.015 inches) to facilitate the
same fluid flow, as compared to that of thicker membranes having a
larger number of pinholes. Note also that stiffening ribs 259 may
be integrally molded on the inside of neck structure 254 to resist
collapse of nipple 250 during use. In one embodiment, membrane 255
is indented by an amount I (e.g., 0.015 inches) below the uppermost
portion of neck structure 254.
FIG. 12 is a side view showing a sippy cup 300 that utilizes a flow
control element 350 formed in accordance with another specific
embodiment of the present invention. Sippy cup 300 generally
includes a hollow cup-shaped body 310, and a cap 340 having flow
control element 350 mounted thereon. Body 310 includes a roughly
cylindrical sidewall 311 having a threaded upper edge 313, and a
bottom wall 315 located at a lower edge of sidewall 311. Sidewall
311 and bottom wall 315 define a beverage storage chamber 317 in
which a beverage BVG is received during use. An optional cold plug
320 is mounted on bottom wall 315, as described in co-owned U.S.
Pat. No. 6,502,418 issued Jan. 7, 2003. Cap 340 includes a base
portion 342 having threaded inside surface that mates with threaded
upper edge 313 to connect cap 340 to body 310, thereby enclosing
storage chamber 317. Cap 340 also includes a drinking spout 345
defining an outlet passage 346. Provided at a lower end of drinking
spout 345 is a cylindrical mounting structure 347 to which flow
control element 350 is press fitted. Cylindrical mounting structure
347 forms a flow channel through which liquid passes from storage
chamber 317 to outlet passage 346.
Referring to FIGS. 13 and 14, flow control element 350 is formed
according to the generalized embodiment described above, and
includes several peripheral pull-tabs 352, a cylindrical wall
section 354 extending away from pull-tabs 352, and a membrane 355
extending across one end of cylindrical wall 354. Pull-taps 352 are
formed by a flat, relatively thick section of the elastomeric
material, and provide convenient handles for removing flow control
element 350 from cap 340. Cylindrical wall 354 is also relatively
thick, and defines a central axis X that extends substantially
perpendicular to the plane defined by pull-tabs 352. In contrast,
membrane 155 is relatively-thin, and in the disclosed embodiment is
located in the plane defined by pull-tabs 352. In accordance with
the present invention, several pinholes 358 and 359 are formed in
the manner described above with reference to pinholes 58 and 59 of
the generalized embodiment to facilitate liquid flow from storage
chamber 317 through drinking spout 345 in the manner described
above.
FIG. 15 is a side view showing a portion of a sippy cup 400
according to yet another embodiment of the present invention.
Similar to the first embodiment discussed above, sippy cup 400
utilizes a cap 440 and body (not shown) that are similar to cap 340
and body 310, which are described above. However, sippy cup 400
utilizes an elastomeric flow control element 450 mounted on cap 440
that differs from flow control element 350 in the manner described
below.
Referring to FIGS. 16 and 17, flow control element 450 is formed
from a suitable elastomeric material (e.g., soft rubber,
thermoplastic elastomer, or silicone), and includes several
peripheral pull-tabs 452, a cylindrical wall 454 extending away
from pull-tabs 452, and a membrane 455 extending across the end of
cylindrical wall 454 that is located opposite to pull-tabs 452.
Similar to the above-described sippy cup embodiment, pull-taps 452
are formed by a flat, relatively thick section of the elastomeric
material. However, membrane 455 is positioned below the plane
formed by tabs 452 (i.e., at a lower end of wall 454). The outer
diameter of cylindrical wall 454 is provided with a slight taper
(as indicated in FIG. 16) to facilitate insertions into cylindrical
mounting structure 447 of cap 440 (as shown in FIG. 15), and is
sized to be secured (i.e., press fitted) to cap 440 when
cylindrical wall 454 is pushed into mounting structure 447. As in
the embodiment described above, flow control element 450 includes
pinholes 458 and 459 that are formed in the essentially the same
manner described above to facilitate different flow rates at
different applied differential pressures.
In addition to the general and specific embodiments disclosed
herein, other features and aspects may be added to the novel flow
control elements that fall within the spirit and scope of the
present invention. Therefore, the invention is limited only by the
following claims.
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