Note: Descriptions are shown in the official language in which they were submitted.
;~O 93~18986 ~117 9 2 4 P~tCA93~00106
GA~-COI\ITAlI\IING PRODUCT SUPPORTlNG STRUCTURE
TECHNICAL FIELD: -
This invention relates generally to product supporl ~ackaging inserts and more
particularly to ecologically advantageous packing inserts for supportin~ products within
outer shipping cartons and protecting the supported products against external shsck.
BACKGROUND OF THE INYE~TION:
Wh.e-l shipping fragile products, it is desirable to provide protection against external
shock which is as complete ~as possible and, at the same time, minimi7e both packaging
and shipping costs. In the past, both expanded polystyrene (EPS or styrofoam) and
polyurethane or polyethylene (flexible foam) inserts have been used for such purposes with
considerable success. In recent years, however, environmental concems over both EPS
and flexible foams have been growing. Both are very voluminous per pound and thus tend
to exhaust landfill areas much too quickly. Any foamed plastic prod is, moreover, both
dif~lcult and costly to rec!aim or recycle back to its original non-foan1ed state. There is,
therefore, an ongoing need for new packaging techniques which not only provide aa .}uate
protection to products agains-~ external shock and n-inimi7~ both packag1ng and shipping
costs but also present minim~l ecologlcal problems in the disposal of packaging materials
after they have served their intended purpose.
:
SUMMARY OF THE INV~,NTION: -
The present invention generally takes the form oi' a supporting structure for
positioning and supporting a~product within an outer packing container. In accordance
wi~h a principal aspect of the invention, that structure is self- s~orting and is also
capable of supporting loads thereon, thus becoming a main sl ~porting element, and further
uses a gas such as air as the other main supporting element. ln the preferred embodiment
the supporting structure comprises a product specific gas-containing bladder or air bladder
with an externai cavity on one side or in a first region thereof. The cavity is shaped to fit
the external pre-deterrnined configuration and dimensions of the product and with its
WO 93/18986 2 1 1~ 9 2 1 PCT/CA93/00106
exterior on the other side or in a second opposed region shaped to flt internal
dimensions of the packing container or shipping carton. The air bladder may be either a
vertical or a horizontal positioning element and rnay typically be used in sets of top and
bottom pairs within a single outer packing container. The air bladder provides both
product suppo~rt and impact protection during storage and ~}ipping and can be easily
collapsed a~ter use. Collapsed, the air bladder is compact an~ can be re-used indefinitely
before it is finally re-cycled, and need not be discarded, thus nlinimi7.ing environmental
impact. Before final assembly for shipping, air bladder r~aterials require relatively little
storage space and even fo~ned air bladders can themselves be stored either wholly or
partially deflated to save space.
For purposes of this patent application, use of the term "inflated" to refer to gas
~ithin an air bladder or other gas-containing bladder shall mean that there is gas within
the bladder. The ~as may be at ambient pressure (zero gauge pressure), or somewhat
above or below zero gauge pressure. &enerally, the bladder is not purposely inflated
above atmospheric pressure, either during manufacture or at the time of use.
Correspondingly, the term deflated shall mean that the bladder has been collapsed, with
a small amount of gas remaining therein~ Likewise, semi-inflatecl or semi-deflated means
that the bladder is in a partially collapsed condition with a corresponding amount of gas
therein.
In accordance with anothet aspect of the invention, the air bladder is composed of
a plastic resin material such as polyethylene~ and is produced by blow molding. Blow
molding involves extruding a semi-solid tube of the plastic material into a mold having the
product's outer wall shape. After the mold is closed, a jet of air from a nozzle forces the
plastic material to expand and contact the metal walls of the mold. The plastic resin is
cooled and hardened almost instantly as the mold is kept cool by circulating water through
built-in internal cavities. Blow molding is well know and is already the process of choice
in the manufacture of many commercial products such as large soft drink bottles, gas cans,
and even garbage cans. Use of blow molded plastic material is particularly advantageous
environrnentally with respect to the present invention in that the materials it makes use of
may be recycled with a minimum of cost or inconvenience. There are, furthermore, no
environmentally hazardous substances or expansion a~ents which are used in the
O 93~18986 2I I 7 9 2 ~ PCI/CA93/00l()6
manufacturing process. Moreover, the material of the air bladder itself can be made up
with virtually 100% recyclable ma~erial, due to modern recycling techniques.
In accordance with an important aspect of the invention, the air bladder may
contain a plurality of interior chambers or compartments. Such interior chambers, when
present, provide location controllable damping by way of separate air shock absorbers in
areas such as corners subject to potentially higher impacts. When a passage is provided
between one chamber and another, the size of the passage is controlled by baffling and has
a direct influence on the rapidity with which those chambers will deflate under load. A
high degree of controllable damping is thus provided. Alternatively, multiple air bladder
chambers may be entirely sealed from one another in order to provide maximum isolation
if needed to meet directional load requirements. When air bladder chambers are sealed
from one another in this manner, the blow molding process makes use of a separate
inflation nozle fior each chamber. This aspect of the invention adds yet anothercontrollable design element to protective packaging technology, allowing smaller and
effectivé protective packing containers or shipping cartons.
Damping is also realized due to ~he increased pressure of the gas within the
bladder. Special gases such as sulphur hexafluoride may be used to maximize the damping
capacity of the gas. Further, damping is also obtained as a result of the resiliency of the
plastic that constitutes the air bladder and also from the relatively small amount of
elasticity of that plastic. In terms of damping, it is detrimental to have too much elasticity
in the plastic material because this amoun, of elasticity could cause motion to be returned
to the product being supported. Other gases that may be used include carbon dioxide,
nitrogen, argon and krypton.
In accordance with yet another aspect of the invention, the air bladder may be
further inflated with air or other gases as desired either before or after the air bladder has
been sealed, and even after assembly of the product and the air bladder within the packing
container. The air bladder may thus, when required, be only partially inflated or even fully
deflated after manufaeture, allowing the air bladder to take up less room during shipping
of the air bladder per se and also m~kinE final assembly of the product and one or more
air bladders within the container easier to accomplish. After final assembly, inflation
needles can be forced through the outer container at one or more predetermined inflation
WO 93/189~6 2117 9 2 4 PC~/CA93/001~-
points, where they penetrate the designated air bladder chambers and inflate them to
designated pressure levels.
The supporting structure is a semi-rigid self supporting monolith that is made from
relatively thick polyethylene plastics material or similar, preferably by a blow molding
process. The structure has been designèd with tfie properties of typical polyethylene
plastics in mind. Polyethylene plastic having a thickness of about 1/32" is resilient and
slightly elastic, and is also stiff enough to support an appreciable load if used in a suitably
designed ioad bearing structure.
The load bearing supporting structure must perforrn the following functions:
- support a static vertically oriented load (all or at least a
portion the weight of the product);
- support a vertically oriented dynamic load due to vertically
displaced motion of the product or outer package;
- support a horizontally oriented (in the other two dimensions)
dynamic load due to horizontally displaced motion of the
product or outer package;
- de~orm so to cushion the product from high accelerative or
decelerative forces. with such deformation being realized
over as large a displacement as reasonably possible, so as to
Ininimi7e the forces transmitted to and therefore absorbed by
the product.
The product supporting structure of the present invention has been designed so as
to have walls thick enough to support a static load of several pounds so that a product may
be supported by the strength of the walls alone, and also to absorb the extra forces caused
by dynamic loading.
The product supporting structure of the present invention has also been designedso as to have walls that are thin enough to be at least partially defolmable under typical
loading conditions, so that the overall structure will deform and thus absorb the force of
the load over a relatively large displacement, at least as large as reasonably possible. Such
large displacement deformation helps to minimi7e the deceleration forces encountered in
receiving and supporting a load and in damping the motion of dynamic loading.
.~0 ~3/18986 21~ 7 9 2 ~ PCr/CA93/00106
The walls must be thin enough to be resiliently and somewhat elastically
deformable so that the structure will non-permanently deforrn under a static or dynamic
load caused by the weight of the material and the movement of the material to be absorbed
without perrnanently defoarning the material. The elasticity allows the stmcture to return
to its original shape after it has been deforrned by a load, within limits. If the walls are
too thick, then the structure will not deform by a significant amount lnd therefore will not
be able to minimi7~ the accelerative or decelerative forces impar~ed to it. Further, the
structure will be less resilient and be more likely to be perrnanently deforrned if it is
deformed by at least a certain amount, and will be less likely to elastically return to its
original shape.
The invention may be better understood from the following more detailed
description of several specific embodiments, taken in the light of the accompanying
drawing and the appended claims.
BI~IEF DESCR~?TION OF THE DRAWINGS:
Figure 1 Illustrates a product supporting vertical end cap air bl2dder embodyingvarious aspects of the inventlon;
Figure 2 is a plan ~view showing detaiis of the end cap air bladder illustrated in
Figure 1;
Figures 2A, 2B, and ~C are cross-sectional views of the end cap air bladder shown
in Figure 2,
Figure 2D is a side view of the end cap air bladder shown in Figure 2;
Figure 3 illustrates product supporting horizontal tray air bladders embodying
various aspects of the invention;
Figure 4 shows an inflation gun suitable for post molding inflation of air bladders
embodying various aspects of the invention;
Figure 4A illustrates tip details of the inflation gun shown in Figure 4;
Figure 5 is an exploded isometric view of a further specific embodiment of the
present invention showing a discrete product supporting structure co-operating with the
corner of a product and the corner of an outer package; and
Figure 6 is a cross-sectional view of the product supporting structure of Figure 5.
WO 93/18986 PCT/CA93/001(;~, -
2ll~92~
DE~TATLED DESCRIPT~ON:
In order to properly understand the present invention, it is necessary to first
understand the applied physics of the situation where impact forces would be experienced
by the outer package containing the product and also expe~ienced by the supporting
structures and the product itself. There are essentially two types of situations. The first
situation involves an outer package in motion, which ha~een impacted by an external
object that may or not be moving, and which decelerates the package. The second
situation involves a package that may or may not be moving, and which is impacted by
an external object that is moving which in turn accelerates the package. The ~ormer case
is more common in the handling and shipment of packages of goods and typically occurs
when a package is dropped. In either case, there is a change of speed of the package and
of the product therein.
In the first situation, Inertial forces of the product are transmitted to the supports,
to the outer package and to the external object. The supporting structure absorbs as much
as possible of the forces. The supporting structure transmits a force to the product, which
causes the product to decelerate. In the second situation, accelerative forces are
transmitted from the external object to the outer package, to the supports and then to the
product. The supporting structure absorbs as much as the force as possible. Some of the
force is transmitted to the product, which in turn accelerates the product.
In either case, there are forces transmitted to the product, and the product must
absorb the energy being transmitted by these forces. If the forces are too high, damage
to the product could result. It is therefore necessary to minimize the forces that reach the
product so that it will not be damaged.
It must be realized that basically what is happening is that kinetic energy is being
transferred to the product. When an outer package is hit by a moving external object, the
kinetic energy of the extemal moving object must be absorbed. When an outer package
is dropped and subsequently impacts onto to a surface such as a floor, the kinetic energy
of the product inside at the time of the impact must be absorbed from the product by the
supporting structure, and so on.
1093/18986 211 792~ PCr/CA93/00106
ln order to absorb kinetic energy while realizing a minimum amount of force
transmitted to the product, it is necessary to distribute the energy absorption ov~er time as
rnuch as possible and to keep the acceleration and deceleration of the product as close to
constant as possible. In order to accomplish this, it is necessary to, among other things,
maximize the displa~ement over which the acceleration takes place. Thus, a relatively
resilient supporting structure is preferable.
In use, when an objeci is introduced to the supportin - structure, the relatively stiff
yet resilient plastic that forms the supporting structure supports the initial weight loading
of the obJect placed thereon. As more of the weight of the object is borne by the
supporting structure, the welght of the object causes the structure to deform and
correspondingly causes the pressure of the gas inside to increase. As the pressure of the
gas inside the support;ng structure, the gas pro~ddes a correspondingly increased support
for the load. The stn~cture continues to defor in a resilient rnanner until the resistive
force provided by th: pporting structure and ihe increase pressure of nhe gas therein are
eq~.a and opposite to the load thereon equilibrium is reached. In this manner, a ~elatively
large displacement of the supporting structure is possible bf ~re equilibrium i eached,
which provides relatively low supporting or damping forces for the object being supported.
In a dynamic load situation, the supporting s~ructur and the p,e ;sure o.~ the gas
therein supports the c:h~n~ing load of a supportlng object in a marmer I.lalogoui to that
described immediately above.
If the supporting structure were inflated to a positive ,,auge pressure of pernaps 2-5
p.s.i., then the pressure of the gas in the supporting structure would help support the
weight of a load placed on the supporting structure virtually as soon as the load is ~ laced
thereon. This means that there would be comparatively less displacemenl of the supporting
structure when a load is placed thereon and correspondingly ~he load would not be
damped over as great a distance -- that is to say that the energ~ from the product being
supported would be absorbed within a short distance and there~ore over a relatively short
period of time~ which in turn would cause relatively high forces to be transmitted to the
product, which may be undesirable.
WO 93/18986 Z 1 ~ 7 9 2 4 PCI /CA93/0010~, -
-
In comparison if the supporting struc~ure does not have a positive gauge pressure,
then the str~lcture would de~orrn for a greater distance after receiving a load, all the while
absorbing energy during the defonnation due to the resiliency of the plastic. By the time
the air pressure was sufficiently high to help support the load, the energy from the
placement of the load would already be partially absorbed and correspondingly lower
forces would be transmitted to the product.
Figure I illustrates a typical application of the invention. In the protective
packaging industry, vertical packaging elements are usually referred to as "end caps",
while horizontal packaging elements are usually referred to as l'trays". Figure 1 shows one
of a pair of "end caps" which~ may, for example, be used in the packaging of personal
computers, In Figure }, an air bladder 11 forming the end cap is shown with a product
receiving cavity 13 facing the viewer. Air bladder 11 is product specific in the sense that,
once forlned, a speci~lc end cap will receive only a product with exterllal dimensions
matching the internal dimenslons of cavity 13 and will only fit within shipping cartons
matching its own external dimensions. Thus, in the illustrated application, the side of a
personal computer rnay fit into the ~cavities 13 of a pair of air bladder end caps and the
entire assembly may be placed In a snug fitting co~l~ugated cardboard box (not shown)
which serves as an outer shippmg container. As an alternative, for instance when an inner
container is desired for housing multiple products, the internal dimensions of cavity 13
may be made to match the external dimensions of that inner container. Such an alternative
may be desirable when multiple products are to be packed within a single inner container,
which is then given protective support withln the outer shipplng container. In a broad
sense, the filled inner container then becomes the product to be stored or shipped.
As shown in Figure 1, product receiving cavity 13 ;n air bladder 11 is bounded by
four respective cor.1er elements l5j 17, 19, and 21 and by two respective side walls 23 and
25. Although many examples of air bladder 11 will have comer elements, the need for
side walls will depend a good deal upon the specific application. A relatively large
product may, for example, require side walls between corner elements 15 and 17 and
between corner elements 19 and 21. A relatively small product, on the other hand, may
not require even the presence of side walls 23 and 25.
.~093~l8g86 21 1 792 ~ PCr/CA93/00106
~ 4ir bladder 11 in Figure I is, in accordance with an important aspect of the
invention, composed of a suitable plastic resin material, such as polyethylene, and is
produced by a blow molding process to form the illustrated e~ ap. In that ~rocess, a
semi-solid tube of t~e plastic resin material is extruded into a rr.old that has the shape of
the product's outer wall. In the instance illustrated, the shape is that of the outer wall of
a personal computer. After the mold is closed, a blast of high pressure air through one or
more holes in the wall of the mold forces the plastic tube to expand and contact the metal
walls of the mold. The plastic resin then cools and hardens as the mold is cooled by
circulating water through internal cavities in the mold. In an application such as that
illustrated in Figure 1, air bladder end cap l l is infiated during the blow molding process
to a gauge pressure of about 3 to 5 pounds per square inch.
Figure 2~is a plan view of end cap alr bladder 11 of Flgure I with the side of air
bladder 11 fonning cavity 13 shown facing the viewer. Figure 2 illustrates several details
not shown in Figure 1, one being the division of air bladder l l into two separately sealed
main chambers 27 and 29, bounded by the exterior dimensions of ~he air bladder and by
side walls 31 and 33, whlch are indicated by respecti~/e dashed lines. Chambers 27 and
29 are thus separated from one another in the vertical plane because of the vertical
orientation of air ~ladder 11. Without the separation, the weight of the product ~a
computer in this instance) would compress the air in lower chamber 29 into upper chamber
27, resultlng in a partial collapse of lower side wall 25 and lower corner elements }7 and
21.
Although main chambers 27 and 29 within air bladder 11 in Figure 2 are sealed
from one another, the invention malces it possible to provide sub-chambers within main
chambers. Such sub-chambers are partially segregated from other chambers in order to
provide a controllable shock damping effect. Examples of such sub~charnbers are comer
elements 15, 17, 19, and 21 in Figure 2. Corner element 15 is molded to be a corner
baffling sub-chamber, defined by the outer walls of air bladder 11 and by fingers or
protrusions 35 and 37 extending from the outside of air bladder 11 into the interior until
they nearly contact one another. The gap 39 left between protrusions 35 and 37 perrnits
the passage of air between the corner baf~ling charnber and main chamber 27 but only at
WO 93/18986 2 1 1 7 9 2 ~ PCI /CA93/0010~''
a relatively slow rate. The degree of isolation of the sub-chamber forming comer element
15 is controlled by the size of gap 39.
As shown in Figure 2, remaining corner elements 17, 19, and 21 are similarly
constructed and provide corner baMing sub-chambers which operate in a similar manner.
Extra shock protection is provided in this manner at respective corners of the ultimate
shipping package. In the interest of clarity, reference numerals 35, 37, and 39 are used
to denote corresponding components in all four corner elements in Figure 2.
Figure 2A is cross-sectional view of air bladder 11 in Figure 2, taken along the line
A-A, which is broken at the center in order to show details of both exterior and interior
construction. Recess 41 in Flgure~ 2A marks the end of side walls 31 and 33 separating
upper and lower chambers 27 and 29. The matching recesses 37 mark the ends of the
''similarly numbered protrusions into those chambers to provide restricted air flow between
upper and lower chambers 27 and 29 and their respective ones of corner sub-chamber
elements 19 and 21.
Figure 2B is another cross-sectional view of air bladder 11 in Figure 2, this time
taken along the line B-B. Here, dividing walls 31 and 33 are farthest apart from one
another. Portions of upper and lower chambers 27 and 29 are shown7 as is recess 41 at the
other end of air bladder 11.
Figure 2C is yet another cross-sectional view of air bladder 11, this time takenalong the line C-C. Here, the er.ds of protrusions 35 and 37 into the interior of air bladder
11 are shown, along wlth gap 39 which is provided between them to provide for the
restricted flow of air needed for corner damping.
Figure 2D, finally, is a side view of air bladder 11, with side wall 25 and corner
elements 17 and 21 facing the viewer. Dashed lines 43 marks the bottom and ends of
product supporting cavity 13 of air bladde'r 11.
Figure 3 illustrates another typical application of the invention, this time providing
horizontal trays for packaging a product such as a television set. In Figure 3, a first air
bladder 51 forms an upper tray and a second air bladder 53 a lower tray. The two air
bladder trays provide respective top and bottom support for a product 55 (shown by dashed
lines~ within a corrugated cardboard outer shipping container 57 (also shown by dashed
lines). Air bladder trays 51 and 53 are shown as mirror images of one another in this
. ,~ 93/189~6 21 ~ 79 2 ~ pcr/cAs3/~o1o6
particular example, for purposes of clarity, but need not be identical as a general
proposltlon.
In Figure 3, holes 59 and 61 are an example of a number of holes extending
entirely through respective air bladder trays 51 and 53 to constrict the passage of air
between various sections of their single main interior chambers by ~rming sub-chambers.
Protrusions 63 and 65, sirnilarly, are examples of protrusions extending partially into
respective air bladder trays 51 and 53 both from the exterior of the air bladders and from
the product supporting ca~tities to perform a similar purpose. In Figure 3, a product
supporting cavity 67 in lower air bladder tray 53 faces up, while a similar product
supportin~ cavity (not seen) in upper air bladder tray 5l faces downward.
In a horizontal application of the invention such as that shown in Figure 3, it is
sometimes advantageous to manufacture respective air bladder trays 51 and 53 initially
slightly deflated. Such slight deflation simplifies the packing process in that the defla~ed
and hence slightly undersized air bladders will more easily fit into corrugated cardboard
outer container 57. After product 55 and the two slightly deflated air bladder trays 51 and
53 are installed within container 57 and container 57 is sealed, air bladder trays 51 and 53
may be furiher infl~ted directly through corrugated cardboard container 57 with an
inflation gun, an example of which is shown in Figure 4.
In Figure 4, an inflation gun 71 is essentially an air valve connected to a hollow
needle upon which there is a small heater element installed within a gun tip 73. Inflation
gun 71 is connected to a regulated air supply (not shown) through an air line 75, and to
a variable power source (not shown) through a power line 77 to control the needle
ternperature. A trigger mech~ni~m 79 on the handle of gun 7I provides the user with on-
off con~rol and a heat adjust knob 81 (also on the handle~ permits accurate control of the
heater element within gun tip 73. An air pressure gauge 83 and a heat gauge 85 complete
the combinatisn. : ~;
Details of inflation gun tip 73 in Figure 4 are shown in Figure 4A. Gun tip 73 is
composed of a neoprene bellows 87 which surrounds a hollow air and heater needle 89
and a heater coil 91. Heater coil 91 encircles the base of needle 89 and bellows 87
compresses upon itself to expose needle 89 when the user presses the gun against an
intended target such as outer container 57 in Figure 3.
wo 93tl8~q ~ 7 9 2 ~ PCr/C~93/001d~ - :
12
In practice, when in the idle mode, needle 89 in Figure 4A remains at a temperature
approximately ten percent higher than the melting temperature of the plastic air~bladder
material. Outer packing container 57 in Figure 3 may have pre-printed inflation point
instructions and markings of locations where the neèdlë is to be forced through corrugated
cardboard container 57 and into the air bladder.~ By way of example, in the areas where
the extruded plastic tube is pinched off and sealed, the air bladder walls are o~en three to
four times thicker than the walls of the rest of the bladder. Such areas, generally, are good
post-assembly inflation points. ~Presslng trigger 79 in Figure 4, will inflate the bladder to
preset pressure level. In order~ to keep needle 89 from continuing to melt the bladder and
creating an oversize opening during the five to ten second filing time, incoming air is
relied upon to drop the temperature of needle 89 quickly below the mel~ing point of the
plastic bladder material. Once the preset pressure is reached and incoming air stops,
needle 89 quickly cycles back up to temperature, allowing it to remelt the plastic to ease
its withdrawal. As needle~ 89 w~thdraws, internal bladder pressure pushes some of the
melted plastic into the hole left by the needle and reseals the bladder.
Upon final disasscmbly when the shipped product reached its destination, graphicinstructions~ on the bladder itself may be used to instruct the consumer to puncture the
bladdèr for easy removal of the product as well as to provide either general of specific
disposal and recycling instruetions. --
Reference ~will now be made to Figure 5, which shows an alternative embodiment -
of the present invention. In this alternative embodiment, a supporting structure l 00 is used
to position and support a product 102 within an outer packing container 104. Typically,
a total of eight such supporting structures l00 would be used, one in each corner of ~he
product 102. The product supporting structure l 00 supports the product l 02 at a
predetermined portion thereof~ The supporting structure l 00 has a predeterminedconfiguration and predetermined dimensions such that it supports the product at the
predetermined portion -- which is of a predetermined configuration. Further, the outer
packing container l 04 has a predetermined configuration, with the supporting structure l 00
to be placed at a predetermined portion thereof.
,~'O 93/18986 21 1 7 9 2 4 PCr/CA93/0010ti
When in use in combinatior, .Lh the product ~02 and the outer packing container
104, the supporting structure comprises a gas-containing bladder I 10 that has a product
receiving portion 112 in a first region of the gas-containing bladder 110. The product
receiving portion 112 has a predetermined configuration and dimensions so as to be co-
operative with the predetermined portion of the product 102 and so as to receive in
generally intimate and co-operating relation thereto the predetermined configuration of the
predetermined portion of the product 102. The predetermined configuration and
dimensions of the supporting structure 100 are adapted to fit the predetermined
configuration of the predetermined portion of the product. Typica!ly, the predetermined
portion of the product is a portion of a corner of the product 102.
The gas-containin~ bladder 1 10 has ~ package containing portion 1 14 in a second
region thereof. The second region is remote from and generally opposed to the first
region. The package containing portion 114 is such as to be co-operati~e w th the
predetermined configuration of the outer packing container 104.
The ;pporting structure 100 has a predetermined size and shape when it is
manufactured. The supporting structure 100 is typically manufactured with an opening
116 therein. A plug 118~s~adapted to fit into the opening in sealed relation thereto and
is inserted therein either imme~diately after manufacture or just before use. Thus, a
sealable opening into the gas-containin~ '-ladder I 10 is provided. When the plug 1 18 is
in place, the gas-containing bladder i lO is sealed to its ambient surroundings. For
shipping ;purposes, the supporting structure may be shipped without tl?e plug ir in wh ch
case it is somewhat collzpsib]e if necessary, or it may be shipped w. ~he plu- ' 8 in . ;e
opening 116. The supporting stmcture 100 retains its size and shape wher. l e gauge
pressure of the gas within the gas-containing bladder 100 is zero, ir- pective of whether
the gas-containing bladder 110 is sealed or open to the ambient surroundings.
The supporting structure 100 is capable of supporting a load th-,reon even when t'le
interior of the gas-containing bladder 110 is in fluid communication with the ambient
surroundings.
The gas-containing bladder 110 may be sealed so as to have a gauge pressure of
the gas therein that is about zero. This will allow for relatively soft cushioned damping
of the product 102. It is also possible to inflate the gas-containing bladder 110 to a gaugc:
WO ~31189862 1 ~ 7 9 2 4 PCr/CA93/001~";
-
1~
pressure above zero, typically within a range of about 0.01 to about 2.0 atmospheres.Such additional gas pressure would cause the air bladder 110 to provide ~Irmer,.damping
for the product 102.
In a further alternative embodiment of the"'invention, the predeterrnined
configuration and dimensions of the supporting structure 100 may be adapted to fit a
predetermined configuration of a predetermined portion of a product, with the
predetermined portion of the product being an edge of the product. For example, a long
slender item may be supported at its centre, or a plate or a drum at selected places around
its circumference.
Preferably, the supporting structure 100 is made of a plastics material having an
average wall thickness in the order of about 1132 of an inch. The material that forms the
supporting structure 100 can be chosen from the group consisting of polyethylene,
polypropylene, and co-polymers thereof~ as well as vinyl, polyvinylchloride, or nylon. The
gas within the gas-containing bladder 110 is most commonly air, but also may be chosen
from the group consisting of nitrogen, carbon dioxide, sulphur hexafluoride, argon and
krypton.
The gas-containing bladder lI0 may comprise a plurality of discrete chambers
therein, with the discrete charnbers being in fluid~ communication with one another through
small openings, which are~ means for restricting gas flow between chambers. These
openings allow a small amount of gas to pass therethrough in a given time, thereby
providing a baffling effect which ultimately aids m the cushioning effect provided by the
gas-containing bladder 110. Preferably, contiguous chambers within the gas-containing
bladder are in fluid communication with one another.
Reference will now be made to Figure 6 which shows the supporting structure 100
of the present invention having the product 102 placed thereon. It can be seen that the
portion of the product 102 that is supported by the supporting structure 100 is a somewhat
complicated shape. and the predetermined configuration and dimensions of the supporting
structure are adapted to fit to the predetermined configuration of the predeterrnined portion
of this product. When the product 102 is placed on the supporting structure 100, there is
a static force~ indicated by arrow I20, which of course is in a downward direction. This
static force I20 causes the supporting structure 100 to deforrn somewhat as shown by the
VO 93/18986 2 I 1 7 9 2 4 PC~/CA93/00106
dash lines 122. If, as usual, the gas-containing bladder 110 is sealed, then the deformation
causes an increase in pressure of the gas within the gas-containing bladder l 1~.
It is to be understood that the embodiments of the invention which have been
described are iilustrative. Numerous other arrangements and modifcations may be readily
devised by those skilled ln the art without departing from the spirit and scope of the
invention.
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