U.S. patent number 3,870,450 [Application Number 05/360,743] was granted by the patent office on 1975-03-11 for multicelled structure apparatus for making same.
Invention is credited to Robert H. Graebe.
United States Patent |
3,870,450 |
Graebe |
March 11, 1975 |
MULTICELLED STRUCTURE APPARATUS FOR MAKING SAME
Abstract
A multicelled structure which may be used as a body support or
other cushioning device has inflatable cells against which a
supported or cushioned body bears. The structure is formed from a
flexible material on mandrels which have a fluted or other shaped
configuration and spaced apart. This prevents the material which is
in a soft or uncured condition from bridging adjacent cells during
the forming operation. The fluting or shape on the resulting cells
is configured to enable the side walls of adjacent cells to closely
approach or contact each other when the cells are expanded by
internal fluid pressure so that the end walls of the cells form a
generally continuous surface.
Inventors: |
Graebe; Robert H. (Belleville,
IL) |
Family
ID: |
23419239 |
Appl.
No.: |
05/360,743 |
Filed: |
May 16, 1973 |
Current U.S.
Class: |
425/269; 425/275;
428/159; 425/403 |
Current CPC
Class: |
B29C
33/00 (20130101); A61G 7/05769 (20130101); B29C
41/14 (20130101); Y10T 428/24504 (20150115) |
Current International
Class: |
B29C
41/14 (20060101); A61G 7/057 (20060101); B29C
33/00 (20060101); B29c 013/00 () |
Field of
Search: |
;425/93,269,275,403,383
;161/116 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Spicer, Jr.; Robert L.
Attorney, Agent or Firm: Gravely, Lieder & Woodruff
Claims
What is claimed is:
1. An apparatus for producing from an initially fluent material a
cushioning device having flexible inflatable cells formed integral
with and projecting outwardly from an intervening layer, said
apparatus comprising: a base member and mandrels projecting
outwardly from the base member such that each of the mandrels
except those mandrels located at the periphery of the base is
surrounded by other mandrels, the base member having an intervening
surface extended between the mandrels with that surface being
substantially continuous and substantially free of voids, the
mandrels being fluted along their sides to form grooves and ribs
with the longitudinal axes of the grooves and ribs for each mandrel
being at a steep angle with respect to the portion of the
intervening surface surrounding that mandrel whereby, when the
mandrels and intervening surface are coated with the initially
fluent material and that material is allowed to solidify, the
cushioning device is formed with the shape of the flexible cells
being determined by the mandrels and the shape of the intervening
layer being determined by the intervening surface on the base.
2. An apparatus according to claim 1 and further characterized by
means on the base member for further forming the material into
embossed channels which open into the interiors of the cells.
3. An apparatus according to claim 1 wherein the ends of the flutes
are spaced from the base member and the portions of the mandrels
between the flutes and the base member form attachment portions at
which the mandrels are connected to the base member.
4. An apparatus according to claim 3 wherein the attachment
portions are of lesser thickness than the fluted portions of the
mandrels so as to form reduced necks at the ends of the cells.
5. An apparatus according to claim 3 wherein the attachment
portions are of greater diameter than the fluted portions of the
mandrels so as to form enlarged connecting pedestals at the ends of
the cells.
6. An apparatus according to claim 3 wherein the attachment
portions are tapered.
7. An apparatus according to claim 3 and further characterized by
elongated embossments extending between the attachment portions of
mandrels for shaping the material into connecting fluid transfer
channels which open into the hollow interiors of the cells.
8. An apparatus according to claim 1 wherein the mandrels are
imperforate.
9. An apparatus according to claim 1 wherein the ribs of each
fluted mandrel are spaced at equal circumferential intervals around
the mandrel.
10. An apparatus according to claim 1 wherein the intervening
surface is substantially planar and the axes of the mandrel ribs
and grooves are perpendicular to the intervening surface.
11. An apparatus for producing from an initially fluent material a
cushioning device having flexible inflatable cells formed integral
with and projected outwardly from an intervening layer, said
apparatus comprising: a base member and mandrels projecting
outwardly from the base member, the base member having an
intervening surface extended between the mandrels with that surface
being substantially continuous and free of voids, each mandrel
having its longitudinal axis presented at a steep angle with
respect to the portion of the intervening surface from which the
mandrel projects, each mandrel also having lontiduinally extending
flutes, the mandrels further being arranged such that each mandrel
except the mandrels at the periphery of the apparatus is surrounded
by other mandrels, whereby when the mandrels and intervening
surface are coated with the initially fluent material and that
material is allowed to solidify, the cushioning device is formed
with the shape of the flexible cells being determined by the
mandrels and the shape of the intervening layer being determined by
the intervening surface on the base.
12. An apparatus according to claim 11 wherein the base has
embossments on the intervening surface with the embossments
extended between adjacent mandrels.
13. An apparatus according to claim 11 wherein the flutes of each
mandrel are spaced at equal circumferential intervals around the
mandrel.
14. An apparatus according to claim 11 wherein the intervening
surface is substantially planar and the longitudinal axes of the
mandrels are perpendicular to the intervening surface.
Description
BACKGROUND OF THE INVENTION
This invention relates in general to multicelled structures such as
a body supporting device and more particularly to a method and
apparatus for forming inflatable devices as well as the inflatable
device itself.
Through clinical tests it has been determined that one of the
better methods of preventing the development of bed sores on
invalids is to support such persons on a series of flexible
intercommunicated cells. Since the cells are intercommunicated all
exert an equal supporting force against the engaged individual.
Such an arrangement of cells is disclosed in U.S. Pat. No.
3,605,145.
In order to have the supporting force distributed over as large an
area as possible, it is necessary to have the sides of the cells in
close proximity to one another and preferably touching one another.
When this condition exists, the ends of the cells form a generally
continuous and conformal surface on which the supported individual
sits or reclines. Such devices may be used for general cushioning
and impact protection purposes also.
Heretofore, the only practical method of producing multicelled
structures with closely spaced or contacting cells was to mold, dip
or otherwise form the cells individually and then secure them to a
base capable of providing physical support and/or
intercommunication between the cells. This procedure is not only
time consuming and expensive, but also leaves the finished product
with a multitude of seams along which leaks may develop. Hence, it
is desirable to form the multicelled structure as an integral
unit.
SUMMARY OF THE INVENTION
One of the principal objects of the present invention is to provide
a process and an apparatus for producing a multicell structure such
as a body supporting device in which the cells are formed along
with a base as an integral unit and when inflated will contact or
nearly contact one another. Another object is to provide a process
and an apparatus of the type stated which are economical and easy
to use. A further object is to provide a process and an apparatus
for producing a multicell structure which has a minimum amount of
seams and hence is very reliable. It is a further object to produce
cells which have a large range of height to diameter or base area
ratios. An additional object is to provide a multicell structure
which is inexpensive and extremely reliable. These and other
objects and advantages will become apparent hereinafter.
The present invention is embodied in an apparatus for forming a
multicell structure having expandable cells which are initially in
a configuration so that the cells when formed are spaced apart but
when later expanded by a pressurized fluid can have various shaped
cross sections and will contact or be closely spaced to one another
at their side walls. The invention also resides in the multicelled
structure itself as well as the process for forming the fluted
cells. The invention also consists in the parts and in the
arrangements and combinations of parts hereinafter described and
claimed.
DESCRIPTION OF THE DRAWINGS
In the accompanying drawings which form part of the specification
and wherein like numerals and letters refer to like parts wherever
they occur:
FIG. 1 is a sectional view of a multicell structure such as a body
support having intercommunicated cells;
FIG. 2 is a plan view of the multicell structure of FIG. 1 and
showing the cells when deflated in interrupted lines;
FIG. 3 is a sectional view of an alternative multicelled structure
having pneumatically independent cells;
FIG. 4 is a perspective view of a flat based tool used to form a
multicelled structure having intercommunicated cells;
FIG. 5 is a detailed elevational view of the fluted mandrels
illustrated in FIG. 4 where the fluted mandrel has a reduced
connecting portion;
FIG. 6 is a plan view of one row of the tool illustrated in FIG.
4;
FIG. 7 is an elevational view of a alternate fluted mandrel which
may be used to form the multicelled structure of FIG. 1 where the
fluted mandrel has a conical pedestal like connecting portions;
and
FIG. 8 is a plan view of the tool illustrated in FIG. 7.
DETAILED DESCRIPTION
Referring now to the drawings (FIGS. 1-3), S designates a multicell
structure which forms part of the present invention and is produced
with the tooling and in accordance with the process of the present
invention. The multicell structure S includes a plurality of cells
2 attached to a common base 4 comprised of an intervening layer 6
occupying the area between the cells 2 and a sealing layer 8
underlying the intervening layer 6. The intervening layer 6 is
preferably embossed between adjacent cells 2 to provide internal
fluid transfer channels 10 which interconnect the cells 2 so that
all the cells 2 are in communication (FIG. 1). This results in
equal pressure within the cells 2. However, the cells 2 may be
pneumatically independent of one another (FIG. 3).
The base should be provided with a valve for inflating the body
support S. The multicell structure S is used as a cushioning device
or impact aborbing device. It is ideally suited for use as a body
support such as a mattress or seat cushion. Each cell 2 has a side
wall 12, an end wall 14, and a connecting portion 16 interposed
between the side wall 12 and intervening layer 6 of the base 4 for
attaching the cell 2 to the base 4. The connecting portion may take
the form of a reduced neck 16a (FIG. 3) or a flared or otherwise
enlarged pedestal 16b (FIG. 1). When deflated the side wall 12
possesses a fluted configuration, and the side walls 12 of adjacent
cells 2 are spaced a substantial distance apart (FIG. 2, dotted
lines). However, when the cells 2 are pressurized, the side walls
12 assume a generally cylindrical configuration or they can be made
to form other cross-sectional shapes. However, the side walls 12 of
adjacent cells 2 may contact and interfere with one another to such
an extent that they deform each other into more or less rectangular
configurations (FIG. 2, full lines). The fit is quite tight, and as
a result the end walls 14 of the air cells 2 form a generally
continuous outwardly exposed surface on multicell S. This surface
will conform to objects forced against it and hence may be
described as a conformal surface. The fluid transfer channels 10
when used may be provided with restrictions 18 to regulate the rate
of fluid transfer between cells 2.
The apparatus or tool A for forming the multicell structure S
includes (FIGS. 4-8) a base member 30 having a generally flat
surface 32, and mandrels 34 projecting outwardly from the surface
32. The mandrels 34 are arranged in longitudinally and transversely
extending rows (FIG. 4). Moreover, the mandrels 34 are spaced from
one another as may be required to accommodate a mix of mandrel
sizes.
Each mandrel 34 for most of its length is fluted, having a fluted
portion 36 provided with a plurality of radially directed ribs 38.
The longitudinal axis of each mandrel 34 as well as the
longitudinal axes of the ribs 38 thereon are perpendicular to the
intervening flat surface 32 and are hence disposed at a steep angle
with respect to that surface. The upper ends of the ribs 38 may be
tapered to affect the pressurized shape of the cell 2 formed
thereon. The opposite end of the fluted portion 36 merges into the
attaching portion 40, or may extend all the way to the surface 32
on the base member 30. If the tool A is to form cells 2 having
reduced necks 16a, then the attaching portion 40 of the mandrel 34
should taper inwardly (FIG. 5). On the other hand, if the mandrel
34 is to form cells 2 having a flared pedestal 16b, then the
attaching portion 40 of the mandrel 34 should flare outwardly (FIG.
7). When the fluid transfer channels 10 are desired in the
multicell structure S, the attaching portions 40 of adjacent
mandrels 34 are joined by elongated embossments 42 which project
outwardly from the surface 32 of the base member 30. Approximately
midway between their ends the embossments 42 may be reduced in
thickness to form necks 44.
The cells 2 and the intervening layer 6 of the multicelled
structure S may be formed as an integral unit by dipping the tool A
into a vat containing a suitable coating material in liquid or
semiliquid condition. The tool A is immersed sufficiently to enable
the liquid to cover and coat the flat surface 32 on the base member
30. The material should, of course, adhere to the mandrel 34 so as
to coat the mandrel 34 as it is dipped. Preferably, this material
is of such a nature that it can be cured to a flexible impervious
condition. The tool A is dipped to provide a coating of desired
thickness, and once this coating is acquired, the tool A is removed
from the vat and the coating is cured to the extent that it assumes
desired characteristics. Then the integrally formed cells 2 and
intervening layer 6 are stripped from the tool A. If the cells 2
are formed with enlarged pedestals 16b, or have ribs 38 extended
straight to the surface 32, adequate draft angles can be used to
permit the use of a two piece pressure mold as may be used for
injection molding. In this connection, the cells 2 and integral
intervening layer 6 can be formed in an injection molding operation
also.
Once the integrally formed cells 2 and intervening layer 6 are
removed from the tool A, the sealing layer 8 of the base 4 is
adhesively or otherwise secured to the back face of the intervening
layer 6, both along the periphery of the base 4 and also between
adjacent air cells 2. The sealing layer 8 is merely a flat sheet of
suitable material. As a result those portions of the intervening
layer 6 which are molded about the elongated embossment 42 will be
raised from the sealing layer 8 and hence, from the fluid transfer
channels 10 in the common base 4. Since the sealing layer 8 is
secured to the intervening layer 6 between adjacent cells 2; the
base 4 will not balloon outwardly when the multicell structure S is
pressurized.
The ribs 38 on the fluted portion 36 of the mandrel 34 enable the
cells 2 to be formed in a configuration relatively small in
diameter. This, in turn, prevents the coating material from
bridging adjacent mandrels 34 so that the cells 2 as formed are
separate and distinct from one another. They need not be cut apart.
Nevertheless, the ribs 38 provide sufficient wall surface on the
side walls 12 of the cells 2 to enable the cells 2 when pressurized
to assume a much larger diameter. Indeed, the side walls 12 possess
sufficient material to enable adjacent cells 2 to contact one
another and in so doing substantially deform each other. As a
result, the end walls 14 of the cells 2 form a substantially
continuous surface across the upper end of the body support S.
Other mandrel shapes can also be used. A rectangular or otherwise
elongated cross sectional shape in lieu of a fluted cross sectioned
shape for the mandrels 34 would produce cells 2 which would also
tend to assume a cylindrical configuration when pressurized and
therefore be made to contact adjacent cells 2. The fluted mandrel
yields the largest cell inflation diameter to mandrel diameter and
is therefore the preferred configuration.
When the multicell structure S is made with all the cells 2
flexible and intercommunicated through the fluid transfer channels
10, the continuous upper surface formed by the end walls 14 of the
cells 2 is highly conformal in nature and will easily conform to
the contour of objects placed against it. For example, if an
invalid sits or reclines on the multicell structure S, the end
walls 14 of the cells 2 will conform to and contact practically the
entire skin area overlying the multicell structure S. Therefore,
the supporting force exerted by the multicell structure S is spread
over the entire skin area and is not concentrated in localized
areas as is true of mattresses of current construction. As a
result, the chances of bed sores developing are minimized when the
structure S is used as a mattress or seat cushion for invalids.
In lieu of forming the base member 30 of the tool with a flat
surface 32 from which the mandrels 45 project, the surface 32 may
be cylindrical or spherical.
The cells 2 and intervening layer 6 need not be formed from a
flexible or elastomeric material, but instead may be formed from a
material such as a metal. In that case the metal can be applied on
the mandrels 34 and base 30 in a electroforming process.
This invention is intended to cover all changes and modifications
of the example of the invention herein chosen for purposes of the
disclosure which do not constitute departures from the spirit and
scope of the invention.
* * * * *