U.S. patent number 3,776,408 [Application Number 05/157,409] was granted by the patent office on 1973-12-04 for nursing unit.
This patent grant is currently assigned to Scott Paper Company. Invention is credited to Stephen A. Wald.
United States Patent |
3,776,408 |
Wald |
December 4, 1973 |
NURSING UNIT
Abstract
A nursing unit having a disposable, seamless, plastic liner for
containing liquid; a self-supporting tubular holder for the plastic
liner and a nipple for closing an open end of the tubular holder.
The disposable, seamless, plastic liner has a flexible, collapsible
body portion defining a cavity for containing liquid, and an upper,
firm flange extending transversely beyond an outer side surface of
the body portion. The body portion collapses as liquid is drawn out
of the liner during nursing to prevent the formation of a vacuum in
unfilled portions of the cavity. The flange defines and maintains
an open mouth under ambient, uniform pressure when said flange is
unsupported by the holder, said open mouth permitting egress and
ingress of liquid. The flange is clamped between an upper margin of
the tubular holder and a downwardly extending shoulder on the
nipple.
Inventors: |
Wald; Stephen A. (Wallingford,
PA) |
Assignee: |
Scott Paper Company (Delaware
County, PA)
|
Family
ID: |
22563595 |
Appl.
No.: |
05/157,409 |
Filed: |
June 28, 1971 |
Current U.S.
Class: |
215/11.3;
220/495.06 |
Current CPC
Class: |
A61J
9/001 (20130101) |
Current International
Class: |
A61J
9/00 (20060101); A61j 009/00 () |
Field of
Search: |
;215/11R,11E ;220/63R
;150/.5 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1,294,758 |
|
Apr 1962 |
|
FR |
|
871,425 |
|
Jun 1961 |
|
GB |
|
Primary Examiner: Rothberg; Samuel B.
Assistant Examiner: Marcus; Stephen
Claims
What is claimed is:
1. A disposable, seamless, thermoplastic liner adapted to receive
and contain liquid and adapted to be supported in an opening
defined within a self-supporting holder of a nursing unit, said
plastic liner being drawn from a sheet of thermoplastic material
and comprising:
A. a flexible, collapsible body portion of a pre-shaped and set
self-supporting open configuration which is sustained under
ambient, uniform pressure, said body portion including a
substantially continuously rounded bottom region and a sidewall
region extending upwardly and tapering outwardly from said bottom
region said body portion defining a cavity for containing liquid
and terminating at an upper end defining an open mouth into said
cavity for permitting egress and ingress of said liquid, said body
portion being sufficiently thin for permitting at least a
substantial portion thereof to collapse as liquid is drawn out of
said liner during nursing to prevent the formation of a vacuum in
said cavity during substantially the entire nursing operation,
whereby a steady flow of liquid from said liner is achieved without
labored sucking and excessive air swallowing; and
B. an upper, firm flange extending outwardly from and transversely
beyond the upper end of said body portion, said flange being
thicker than said body portion and non-collapsing during handling
of said liner for sustaining said mouth in an open configuration
when assembling said liner with a self-supporting holder, said
flange being adapted to be supported on an upper margin of a
self-supporting holder of a nursing unit.
2. The disposable, seamless, plastic liner according to claim 1,
wherein said flexible, collapsible body portion collapses under a
pressure differential of less than 0.5 lbs. per square inch.
3. The disposable, seamless, plastic liner according to claim 1
having an internal depth to maximum internal transverse dimension
ratio of greater than 2:1.
4. The disposable, seamless, plastic liner according to claim 3,
wherein said body portion has a thickness of between approximately
1-1/2 mils and 8 mils.
5. The disposable, seamless, plastic liner according to claim 3,
wherein said internal depth to maximum internal transverse
dimension ratio is in the range of 2:1 to 3:1.
6. The disposable, seamless, plastic liner according to claim 5,
wherein said flexible, collapsible body portion collapses under a
pressure differential of less than 0.5 lbs. per square inch.
7. The disposable, seamless, plastic liner according to claim 6, in
combination with at least one other liner of the same construction,
said liners being disposed in telescopic relationship with each
other.
8. The disposable, seamless, plastic liner according to claim 5,
wherein said body portion has a thickness of between 1-1/2 mils and
8 mils.
9. The disposable, seamless, plastic liner according to claim 8,
wherein said flexible, collapsible body portion collapses under a
pressure differential of less than 0.5 lbs. per square inch.
10. The disposable, seamless, plastic liner according to claim 9,
in combination with at least one other liner of the same
construction, said liners being disposed in telescopic relationship
with each other.
11. The disposable, seamless, plastic liner according to claim 1,
in combination with at least one other liner of the same
construction, said liners being disposed in telescopic relationship
with each other.
12. A nursing unit including a self-supporting tubular holder
having an inner wall defining an opening therein which terminates
at an upper margin of said holder; a seamless, thermoplastic liner
drawn from a sheet of thermoplastic material, said liner including
a body portion disposed within the opening of said holder and a
flange disposed on the upper margin of said holder, said body
portion including a bottom region and a side wall region defining a
cavity for containing liquid, said side wall region terminating at
an upper end defining an open mouth into said cavity for permitting
egress and ingress of liquid, said flange extending outwardly from
and transversely beyond the upper end of said body portion; and a
nipple disposed on said holder for closing the open end thereof,
said nipple having a shoulder overlying the upper margin of said
holder for clamping the flange of the liner between the shoulder of
the nipple and the upper margin of the holder to retain the liner
in assembled relationship with the nipple and the holder, wherein
the improvement comprises said bottom region of the body portion
being substantially continuously rounded, and said side wall region
extending upwardly and tapering outwardly from said bottom region,
said body portion of said liner being of a pre-shaped and set
self-supporting open configuration which is sustained under
ambient, uniform pressure, said body portion being sufficiently
thin for permitting at least a substantial portion thereof to
collapse as liquid is drawn out of said liner during nursing, said
body portion having a transverse dimension relative to the
transverse dimension of the opening in the holder for permitting
the body portion to be assembled and maintained within the opening
of the holder without transverse distortion of the pre-shaped open
configuration of said body portion said flange being thicker than
said body portion and non-collapsing during handling of said liner
for sustaining the mouth of the liner in an open configuration when
assembling said liner with the self-supporting holder.
13. The nursing unit according to claim 12, wherein said flexible,
collapsible body portion collapses under a pressure differential of
less than 0.5 lbs. per square inch.
14. The nursing unit according to claim 12, said plastic liner
having an internal depth to maximum internal transverse dimension
ratio of greater than 2:1.
15. The nursing unit according to claim 14, wherein said body
portion has a thickness of between 1-1/2 mils to 8 mils.
16. The nursing unit according to claim 12, wherein the side wall
region of the body portion of the liner in the preshaped open
configuration of said body portion is spaced inwardly from the
inner wall of the tubular holder, whereby the liner can be
assembled with the tubular holder without altering the pre-shaped
open configuration of said body portion.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a nursing unit, and more specifically, to
a nursing unit having a disposable, plastic liner for receiving and
containing liquid.
2. Description of the Prior Art
Nursing units having presterilized, disposable, collapsible liners
for containing milk or other liquids to be fed to an infant have
become quite popular. These liners are not selfsupporting and
require the use of a holder to support them during use of the
nursing units. The liners are so flexible as to be extremely
difficult to handle and assemble with the supporting holders, and
in some cases a special mechanical insertion device, such as is
disclosed in U.S. Pat. No. 2,900,779, must be utilized to secure
the liners to the holders. Alternatively, these liners have been
provided with tab extensions adjacent the upper ends thereof, as
exemplified in U.S. Pat. No. 3,204,855, and these tabs are manually
grasped and pulled outwardly and downwardly about the outer surface
of the holders to define an open mouth in the liners, and to secure
the liners to the holders.
Use of mechanical insertion devices, such as the one disclosed in
U.S. Pat. No. 2,900,779, complicates the use of the nursing unit
and requires sterilization of an additional item. In addition, the
chances of desterilization or contamination are increased in
handling the mechanical applicator. Even when tab extensions are
included on the liners the handling of the liners to assemble them
to a holder is difficult, requiring a degree of manual dexterity
which many people do not possess, due to the extremely flexible
nature of the liners.
The prior art disposable, collapsible liners are made by a
continuous extrusion process in which a plastic tube is
continuously formed and transversely heat sealed at spaced
intervals equal to the desired liner length, as shown in U.S. Pat.
No. 3,204,855, and then packaged in a roll. These heat-sealed
regions define the bottom closure of individual liners, and it is
quite common for the bottom closures of several liners in a given
roll to be defective. These defective closures permit fluid leakage
through the bottom of the liners which obviously is
undesirable.
A nursing unit having a self-supporting disposable liner,
preferably fabricated of paper, is suggested in U.S. Pat. No.
2,110,928. This liner appears to have a reinforcing bottom member
which will prevent the required volumetric collapsing of the liner
to prevent the formation of a partial vacuum in the liner as liquid
is drawn therefrom. The formation of a partial vacuum inside the
liner causes labored sucking and air swallowing during nursing
which may upset the digestive system of an infant. In addition, the
bottom member and side walls of the self-supporting disposable
liner appear to be separate elements which are secured to each
other at a seal region. Separation at the seal region can create a
leakage problem similar to that encountered in the prior art
collapsible liners described above.
SUMMARY OF THE INVENTION
This invention relates to a nursing unit having a disposable,
seamless, plastic liner which is adapted to receive and contain
liquid. The plastic liner has a flexible, collapsible body portion
having an inner surface defining a cavity for containing liquid
therein. At least a substantial elongate portion of said body
portion will collapse as fluid is drawn out of said liner during
nursing to provide a steady flow of liquid by preventing the
formation of a vacuum in unfilled portions of the cavity. The
creation of a vacuum in an unfilled portion of the cavity can cause
labored sucking and excessive air swallowing which will upset the
digestive system of an infant. The liner further includes an upper,
firm flange for defining and maintaining an open mouth under
ambient, uniform pressure when said firm flange is unsupported by a
holder, said open mouth permitting egress and ingress of liquid.
The flange extends outwardly beyond an outer side surface of the
body portion of the liner to seat on an upper margin of a
self-supporting holder. The firm flange construction facilitates
the assembling of the liner with a holder in a manner which has not
been achievable with prior art collapsible plastic liners. The
plastic liner of this invention has an internal depth to maximum
width ratio of greater than 2:1, and is deep drawn from a sheet of
plastic material in a thermo-forming operation.
In the preferred embodiment of the invention the body portion is
sufficiently self-supporting to substantially maintain a preshaped,
open configuration under ambient, uniform pressure; and is
sufficiently flexible to collapse as fluid is sucked out of the
liner through a nipple secured to the upper end of the supporting
holder. Preferably the body portion of the liner is sufficiently
flexible to collapse as fluid is permitted to exit therefrom by
gravity when the nursing unit is turned upside down, i.e. the body
portion of the liner is sufficiently flexible to collapse without
the aid of suction created during nursing.
The plastic liner can be grasped about the outer margin of the firm
flange and inserted into the opening of a hollow holder such that
the flange is supported on an upper margin of said holder. The
plastic liner of this invention is inserted in the holder more
easily than prior art collapsible liners, and this ease of
insertion results from the firm construction of the flange which
maintains the mouth of the liner in open condition under ambient,
uniform pressure.
A nipple is removably secured to the holder for closing the open
end thereof, and the nipple has a downwardly extending shoulder
overlying the upper margin of the holder for clamping the flange of
the liner between the downwardly extending shoulder of the nipple
and the upper margin of the holder.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded isometric view of the various elements
forming the nursing unit of this invention;
FIG. 2 is a longitudinal sectional view through the assembled
nursing unit showing the approximate configuration of the
disposable liner in solid lines prior to and after receiving liquid
therein, and showing schematically the collapsed condition of the
liner in dashed lines after nursing of an infant; and
FIG. 3 is a schematic view, in section, of a single thermoforming
station of a thermoforming apparatus for forming the disposable
liners of this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION
Referring to FIG. 1, the nursing unit 10 of this invention is
comprised of a self-supporting tubular holder 12; a disposable, or
throw-away seamless plastic liner 14 and a nipple 16. The holder 12
is made of a plastic material, and is self-supporting to retain its
tubular configuration when held by either an adult or child during
nursing, and also when placed on a supporting surface. Other
materials from which a self-supporting tubular holder can be
constructed may be utilized in place of plastic. Also, the
self-supporting holder can be in the form of a ring, such as is
disclosed in U.S. Pat. No. 2,541,934. The self-supporting tubular
holder 12 has an inner wall 18 which defines an opening 20 for
receiving the plastic liner 14. The opening 20 terminates at an
open end defined by an upper margin 22. The bottom of the tubular
holder 12 can be either open or closed. A circumferential groove,
or recess 21 is formed in outer wall 23 of the tubular holder 12 a
short distance below the upper margin 22.
Referring to FIG. 2, the nipple 16 has a downwardly extending skirt
portion 24 which overlies the outer wall 23 of the holder. An
inwardly directed rib 26 is integrally formed with the skirt
portion and cooperates with the circumferential recess 21 for
retaining the nipple 16 to the holder 12. The nipple 16 has an
upper breast portion 28 which is joined to the downwardly extending
skirt portion 24 through a shoulder region 30. The shoulder region
30 has a downwardly facing surface 32 which overlies the upper
margin 22 of the holder 12 when the nipple 16 is secured to said
holder for a purpose which will be described later. The specific
arrangement for retaining the nipple to the tubular holder can be
varied, and is not intended to be limiting on the present
invention. For example, screw-type nipples can be utilized in lieu
of nipple 16.
Referring to FIG. 1, the plastic liner 14 is of a seamless
construction, and is comprised of a flexible, collapsible body
portion 34 and an upper, firm, circumferential flange 36. The body
portion 34 is defined by a side wall region 38 and a rounded bottom
region 40. The side wall region has an outer side surface which is
disposed adjacent the inner wall 18 of the holder 12 when the liner
14 is supported by said holder (FIG. 2). The body portion 34 has an
inner surface 44 which defines a cavity 46 for containing milk, or
other liquid therein. The upper, firm, circumferential flange 36
defines and maintains an open mouth 45 under ambient, uniform
pressure when said flange is unsupported by the holder 12. The
flange 36 extends outwardly beyond the outer side surface of the
liner to define a downwardly facing surface 48 which is adapted to
seat on the upper margin 22 of the tubular holder 12.
The seamless, plastic liner 14 is formed in a preshaped, open
configuration by a thermoforming operation which will be described
later, and the body portion 34 of the liner 14 preferably is
sufficiently self-supporting to maintain said preshaped, open
configuration under ambient, uniform pressure. The body portion is
sufficiently flexible so that at least a substantial elongate
portion thereof will collapse, as schematically shown in dashed
lines in FIG. 2, as a result of the pressure differential created
between the inside and outside of said body portion 34 during the
nursing of an infant. A region of the body portion adjacent the
flange 36 may be prevented from collapsing completely as a result
of being supported by the firmly constructed flange. FIG. 2
schematically indicates the collapsed condition of the liner in
dashed lines after the liner is completely filled with liquid and
drained during nursing. It should be understood that the body
portion of the liner will not necessarily completely collapse in a
transverse direction, but will collapse to a sufficient degree to
accommodate the volumetric displacement of liquid from the liner
during substantially the entire nursing operation to prevent the
formation of a vacuum in regions vacated by the liquid. Thus, the
collapsing of the liner prevents the formation of a vacuum therein
for substantially the entire nursing operation to thereby minimize
labored sucking and air swallowing. The excessive swallowing of air
often upsets the digestive system of an infant, and this problem is
eliminated by the liner 14 of the present invention.
In the preferred embodiment of this invention, the body portion 34
of the liner is sufficiently flexible to collapse as fluid is
permitted to exit from the cavity thereof by the action of gravity
alone when the nursing unit 10 is turned upside down. Stating this
another way, the body portion 34 is sufficiently flexible to
collapse without the increased pressure differential created
between the inside and outside thereof by the sucking action of a
baby during the nursing operation.
The liner 14 can be grasped around the outer periphery of the
flange 36 for insertion into the opening 20 of the holder 12. This
flange 36 is sufficiently firm to prevent collapsing of the open
mouth 45 during handling of the liner 14 to facilitate the
insertion of said liner into opening 20 of the holder. Since the
preshaped open configuration of the mouth 45 is maintained during
handling of liner 14 the necessity of opening the liner and draping
a portion of said liner about the outer side surface of the holder
12 is eliminated.
Referring to FIG. 2, the downwardly directed surface 48 of the
flange 36 is in overlying relationship with the upper margin 22 of
the holder, and seats on said upper margin when the plastic liner
is properly positioned within the holder 12. The downwardly facing
surface 32 of the nipple 16 cooperates with the upper margin 22 of
the holder to firmly clamp the circumferential flange 36 of the
liner between the nipple and holder to assure that the liner is
retained as part of the nursing unit 10 during the nursing
operation.
In the preferred embodiment of the invention the body portion 34 of
the plastic liner is self-supporting under ambient, uniform
pressure and thereby facilitates the handling of the liner for
insertion into the opening 20 of the tubular holder 12. It is
within the scope of this invention to provide a disposable,
seamless, plastic liner in which the body portion is not
sufficiently self-supporting to maintain a preshaped open position;
however, a plastic liner in which the body portion is
self-supporting is preferred and is easier to handle. It is
extremely important that the circumferential flange 36 be
sufficiently firm to maintain the mouth 45 of the liner 14 in its
open condition such that the downwardly directed surface 48 of the
flange will be properly positioned to seat on the upper margin 22
of the holder without requiring spreading, or opening of the liner
in the region of the open mouth 45. The downwardly directed surface
48 preferably is planar; however, this surface can assume other
configurations within the purview of this invention. For example,
the flange may be formed such that the lower surface 48 is provided
with a raised area or areas which cooperate with complementary
recesses formed in upper margin 22 of the tubular holder 12. Such
raised areas may be circumferentially continuous areas or discrete
discontinuous areas as desired.
The plastic liner 14 preferably is formed from a sheet of plastic
material in a deep-draw, thermoforming operation, and the plastic
liner has an internal height to maximum internal transverse
dimension ratio of greater than 2:1, and preferably this ratio is
in the range of 2:1 to 3:1. The plastic liner can be made from any
suitable plastic material which can be deep-drawn in a
thermoforming operation, and which will set in its thermoformed
configuration upon cooling. The polyolefins, and in particular
polyethylene, have been found to be suitable for use in forming a
seamless, plastic liner 14 of this invention.
In the preferred embodiment of this invention the seamless, plastic
liner 14 has a circular, transverse configuration; however, other
configurations are within the scope of this invention. Also, the
body portion 34 is tapered in a downstream direction from the open
mouth 45 of the liner to facilitate the stacking of a plurality of
liners into a conventional packaging system. Alternatively, the
liners can be individually packaged, and sold as single units.
In an exemplary embodiment, the seamless, plastic liner 14 of this
invention is deep-drawn in a thermoforming operation into a
substantially cylindrical configuration from a 30 mil thick sheet
of high density polyethylene. The seamless, plastic liner 14 has an
internal depth between approximately 5 to 5-1/2 inches, and a
maximum internal diameter between approximately 2 to 2-1/2 inches.
The circumferential flange 36 is substantially unstretched during
the thermoforming operation and has substantially the same
thickness as the unformed sheet, i.e. 30 mils. The body portion of
the liner has a thickness in the range of between approximately 1.5
mils and 8 mils, and is preferably in the range of 1.5 to 3 mils.
The body portion of the liner collapses under a pressure
differential of less than 0.5 lbs. per square inch.
Referring to FIG. 3, a single thermoforming station 50 in a
thermoforming apparatus is shown, and exemplifies a preferred
method of manufacturing the disposable liners 14. The thermoforming
apparatus can be provided with a plurality of identical
thermoforming stations 50 for forming a plurality of seamless,
plastic liners 14 from a sheet of plastic material; however, for
purposes of explanation, only the single thermoforming station 50
shown in FIG. 3 will be described.
The thermoforming station 50 has a forming assembly 52 movable from
an upstream position (not shown), in which the forming assembly 52
is below the plane occupied by plastic sheet 54, to a downstream
position shown in FIG. 3, wherein the thermoforming of the plastic,
seamless liner 14 of this invention is complete. The body portion
34 of the plastic liner 14 is formed by stretching the plastic
sheet 54 in unclamped regions defined by aligned cavities 56, 58
disposed through clamping plates 60, 62, respectively. The clamping
plates are provided with cooling passages 64 through which a
cooling fluid, such as water or oil, can be passed to cool the
clamping plates and chill portions of the plastic sheet 54 which
are engaged by the clamping plates prior to the thermoforming
operations.
The forming assembly 52 includes a male plug 66 secured to a
support member 68 by any suitable means (not shown). The support
member 68 has a vacuum chamber 70 formed therein which is connected
to a source of vacuum (not shown), and this vacuum chamber 70 is in
communication with a vacuum passage 72 extending through the male
plug 66. The support member 68 extends transversely beyond the
outer periphery of the male plug 66 to define a shoulder 74 facing
in a downstream direction. This shoulder 74 cooperates with an
opposed surface 76 of clamp plate 60 when the forming assembly 52
is in its downstream position shown in FIG. 3 to accurately form
the transversely extending flange 36 of the plastic liner 34.
In operation, the clamp plates 60, 62 are initially opened to
permit the feeding of the plastic sheet 54 therebetween by any
suitable feed means (not shown). The plastic sheet 54 can be heated
by any suitable means, such as a radiant heater (not shown), to a
thermoforming temperature prior to being fed between the clamp
plates 60, 62; or alternatively, the unclamped regions of the
plastic sheet 54 can be heated after the clamp plates 60, 62 are
closed to firmly grasp and confine the plastic sheet 54. The
forming assembly 52 is in its upstream position below the plane of
the plastic sheet 54 as the plastic sheet is fed and clamped
between the clamp plates 60, 62. After the sheet is properly
clamped, the forming assembly 52 is actuated by any suitable means
(not shown) to move said forming assembly from its upstream
position to the downstream position shown in FIG. 3. As the forming
assembly moves to the downstream position shown in FIG. 3, the male
plug 66 engages the unclamped regions defined by the aligned
cavities 56, 58 within the clamping plate 60, 62, to stretch this
region and form the body portion 34 of the plastic liner 14. The
upper and lower clamping plates chill the plastic sheet 54 in the
region adjacent the unclamped regions of the plastic sheet to
prevent excessive stretching in the region which will constitute
the circumferential flange 36 of the plastic liner 14. A vacuum is
pulled through the vacuum chamber 70, and the vacuum passage 72
after the forming assembly 52 has been moved to its complete
downstream position shown in FIG. 3, to thereby create a pressure
differential to assure that the stretched plastic material
constituting the body portion 34 of the liner will closely conform
to the outer periphery of the male plug 66. The sheet is then
permitted to cool with the male plug in its downstream position to
set the plastic material in its stretched condition. The vacuum
application is terminated after setting of the plastic, and the
mold assembly is moved in an upstream direction to a position below
the plane of the unstretched portions of the plastic sheet 54. The
clamping plates 60, 62 are then opened, and the sheet 54 is removed
and fed to a separate severing station (not shown) at which
individual seamless, plastic liners 14 are severed from the plastic
sheet 54.
The male plug can be made from any suitable material which will not
adhere, or stick to the plastic material, and in the preferred
embodiment of this invention, the material is a woven cloth
impregnated with a phenolic resin which is sold under the trademark
SYNTHANE by Synthane, Taylor Corporation of Valley Forge,
Pennsylvania. The support member 68 can be made of any suitable
material, such as steel.
The above-described thermoforming operation is intended to be
representative of one preferred method for manufacturing the
disposable liners of this invention. Other methods can be utilized,
such as the electrostatic spray molding method invented by
SprayMould Ltd., Preston, Ontario, Canada.
* * * * *