The present invention relates to an inflatable bag for
providing a pillow or a cushion and further a closure of an inflatable bag.
Within the technical field of packaging, a particular technique
relating to packaging fragile or costly products in air-inflatable and deflatable
packages is known, which technique is described in, among others,
EP 0 306 204
. Reference is made to the above patent applications and patents and the
above US patents are further hereby incorporated in the present specification by
The commercially available inflatable bags including the
bags described in the above-listed patent applications and patents, however, suffer
from severe drawbags in relation to the complexity of the structure of the bags
and in consequence necessitates the utilization of fairly complex and elaborated
production techniques involving separate and distinct assembling processes and the
combination of a number of individual components to be assembled into the inflatable
EP 1 311 491
, an inflatable bag for protecting fragile products is known and further
from the published European patent application, an inflatable protective cushion
is also known. The technique described in
European patent application, publication No. 1 311 491
constitutes the prior art on the basis of which the present inventors
have developed the novel inflatable cushion or pillow and the closure of the inflatable
On the basis of the technique described in published
European patent application 1 311 491
, a novel application of an inflatable bag has been developed, namely an
inflatable bag for use as a cushion or pillow to be used in hospital applications,
in transportation appliances or in public events such as sports events allowing
a person participating in the sports event as a spectator to use the inflatable
bag as a cushion pillow and obtain a more comfortable sitting position and also
obtaining a high degree of thermal insulation from the supporting seat, which in
numerous instances may e.g. be a concrete, a wooden or steel seat, which in certain
periods of the year may be extremely cold and therefore incomfortable to use as
a sitting support.
A particular feature of the present invention relates to
a surprisingly high load-bearing capability of the bag according to the present
invention, which a load-bearing capability which exceeds the capability which would
be expected from the thighs, i.e. the thickness of the foil materials used.
A particular advantage of the present invention relates
to the use of the provision of a self-sealing closure, which includes no protruding
parts such as the inflatabel closure pockets which are used in the prior art self-closure
bags including self-closure ice cube bags and the inflatable
EP 1 311 491
. The novel closure according to a particular aspect of the present invention,
which provides a highly reliable self-sealing function without using exterior self-closure
pockets extending beyond the constriction of the inlet of the bag prevents the inflatable
bag, when used as a pillow or cushion from being unintentionally deflated by unintentionally
pressing or otherwise manipulating the closure pockets of the prior art self closure
A further advantage of the present invention as compared
to the prior art inflatable bags relates to the improved reliability of the inflatable
bag as compared to the prior art multiple component bags, as the simplyfied inflatable
bag according to the first aspect of the present invention due to a reduced number
of components, is contemplated to be exposed to a reduced failure rate as compared
to the more complex multicomponent prior art inflatable bags.
The inflation medium may in most instances simply be pressurized
air or alternatively be a gas or liquid, such as a low or high molecular weight
gas e.g. a non-combustible and substantially inert gas, such as nitrogen, carbondioxid,
helium or any other low cost gas or alternatively a liquid, such as plain water.
The above object, the above advantage and the features
together with numerous other objects, advantages and features according to a first
aspect of the present invention obtained by an inflatable bag for providing a cushion
or pillow by inflating said bag, comprising:
- two sheets of two-layer foil material, said sheets being of substantially identical
geometrical shape and defining an outer periphery,
- a peripheral joint extending along the major part of said outer periphery of
said sheets, except for a peripheral area constituting an inlet opening of said
bag, said peripheral joint joining said sheets together in substantially overlapping
relationship and defining an inner space within the interior of said bag, and
- a closable and sealable closure being provided at said opening for allowing
an inflation medium to be introduced into said inner chamber through said closable
and sealable closure from the environment.
According to the basic teachings of the present invention,
the inflatable bag according to the first aspect of the present invention is produced
from two-layer foils rather than a single layer foil, which surprisingly provides
an increased strength as compared to a bag produced from a single layer foil having
the same overall thickness as the two-layer foil used in accordance with the teachings
of the present invention.
Below, measuring results support this highly surprising
an unforeseable feature.
The materials used for the two-layer foil material sheets
have, dependent on the actual application and also the inflation medium used, to
comply with certain requirements as to mechanical strength, flexibility, elasticity
and also permeability to the air and further the inflation medium. Preferably, materials
are made from an integral continuous web or webs of a plastics material substantially
impermeable to liquid and/or gas.
Although the inflatable bag according to the first aspect
of the present invention is preferably made from two sheets of two-layer foil material,
which sheets are identical and further from sheets of two-layer foil material including
two layers of identical materials, different polymer materials may be used for the
two layers of one or both sheets characteristic of the inflatable bag according
to the first aspect of the present invention. Furthermore, the sheets may each be
composed of two, three or four layer sheets constituting individual or alternatively
composite or laminated polymer sheets produced from identical or different polymer
materials and even including different foil materials, such as aluminum foils etc.
In the present context, the term bag is to be construed
a generic term representing any element of a type allowing inflation of the bag
for producing a cushion or pillow, however, the term is by no means to be construed
limiting the geometrical configuration of the element in question, as the element
may have any configuration differing from the conventional understanding of the
term or expression bag
The closable and sealable closure may be established in
any appropriate manner by utilizing specific and dedicated means for allowing the
closure to be sealed or closed, e.g. by means of a weld, an adhesive, a separate
closure clamp or similar element after the inflation medium has been introduced
into the inner space of the bag. According to two advantageously embodiments of
the bag according to the first aspect of the present invention, the closable and
sealable closure is established in accordance with a self-closure technique well
known within the art of freezing mould bags, e.g described in
EP 0 264 407
EP 0 574 496
EP 0 616 948
EP 0 825 122
to which patent applications and patents reference is made or alternatively
according to a closure technique including the technique described in
US RE 31890
to which reference is made and which US patent is hereby further incorporated
in the present specification by reference. According to the first embodiment, the
closable and sealable closure is constituted by prolongations of the four sheets,
which prolongations define turned-in parts extending into the inner space.
According to a further refinement of the self-closure valve
technique utilized in the above described first advantageous embodiment of the bag
according to the first aspect of the present invention, which refinement constitutes
a particular and distinct, second aspect of the present invention, the turned-in
parts of the prolongations or extensions are joined together by additional joints
for permanently maintaining the turned-in parts of the prolongations or extensions
in a face-to-face and non-folded state. The additional joints may be constituted
by a single joint connecting the one or both turned-in foil parts to one of the
foil layers of which the turned-in parts constitute prolongations or extensions.
The above-mentioned joint may be constituted by a point or circular weld or similar
connection or joint and furthermore, the turned-in parts may preferably be joined
together by additional joints joining the turned-in parts together without joining
the turned-in parts to the adjacent foil layers which additional joints connecting
the turned-in parts together may be configurated as linear joints, bent, curved
or any other appropriately configurated joints.
According to the above-described alternative embodiment
having a knot-closure, the two sheets define prolongations or extensions, which
are provided with perforations or cuttings defining flaps of the prolongations or
extensions for allowing the flaps to be tied together for providing a closure knot
for closing off the closable and sealable closure.
For establishing a permanent and reliable sealing of the
closable and sealable closure through the use of a closure knot, an additional material
such as an adhesive may appropriately be used in connection with a closure knot
as the adhesive is applied between the two prolongations or extensions prior to
the tying of the knot thereby glueing or adhering the material of the closure knot
The technique utilized for establishing the joints may,
dependent on the material used for the foil material, be welded joints or joints
established by means of a glue or an adhesive material or a combination of welded
and glued joints.
The material used for the foil material may, as stated
above, be any appropriate material exhibiting adequate properties as to permeability
and strength and are further preferably plastics material such as polyethylen, preferably
LDPE or HDPE or any other glueable or weldable foil material, preferably plastics
or polymer foil material or aluminium foil material or combinations of such foil
The inflatable bag according to the first aspect of the
present invention may, as stated above, have any appropriate configurations, such
as a square, a circular, an elliptical, a polygonal or any other geometrical shape,
however, according to the presently preferred embodiment of the inflatable bag according
to the first aspect of the present invention the sheets of two-layer foil material
have rectangular configurations.
The above object, the above advantage and the features
together with numerous other objects, advantages and features according to a second
aspect of the present invention obtained by a closure of an inflatable or self-closure
- two foil layers of substantial identical shape and constituting at least part
of a pair of walls of said bag, said bag defining an inner space delimited by said
pair of walls being joint together by a peripheral joint except for a peripheral
area constituting an inlet opening including said closure,
- said foil layers having at said inlet opening foil prolongations defining turned-in
parts extending from said inlet opening into said inner space of said bag and defining
from said inlet opening a longitudinal extension of said turned-in flaps into said
- a first set of joints extending from said peripheral joint at said inlet transversely
to said longitudinal direction, said first set of joints joining said foil layers
and said prolongations together at a position along said longitudinal extension,
said first set of joints defining a pair of opposite joint ends delimiting the width
of said inlet opening,
- a second set of joints joining said prolongations defining said turned-in parts
together without joining said prolongations or extensions to any of said two foil
layers and extending from said joint ends towards said inner space of said bag,
said second set of joints defining an inlet channel extending from said inlet opening
into said inner space of said bag,
- a third set of joints joining each of said prolongations to a respective foil
layer at said inlet opening, and
- at least one further dot-shaped joint joining said turned-in parts to one of
said foil layers for maintaining said turned-in parts in parallel and stretched
relationship when said closure pockets are filled with an inflation medium and pressurized
as said bag be inflated.
The closure according to the second aspect of the present
invention constitutes a refinement of the closure described in the above-mentioned
European patent application EP 1 311 491
, as the closure according to the second aspect of the present invention
is integrated in the bag and includes no outwardly protruding parts, in particular
no exterior closure pockets. Surprisingly, it has been realised by the inventors
of the invention described in the above-mentioned European patent application and
of the present invention that the second set of joints provided an inlet channel
into the inner space of the bag in combination with the at least one further dot
shaped joint provides a sufficient self-closure effect provided the first set of
joints joining each of the prolongations to a respective foil layer at the inlet
opening are provided.
From the technical field of freezing mold bags or ice cube
bags, self-closure valves are known, such as the self-closure valves illustrated
and described in
EP 0 129 072
, and in the above-mentioned patents
EP 0 246 407
EP 0 574 496
to which reference is made. None of the prior art self-closure valves
of ice-cube bags, however, describe the provision of the inlet channel defined by
a set of joints joining the turned-in valve flaps or foil layers together and a
separate joint linking the turned-in parts to one of the two outer walls of the
According to alternative embodiments of the closure according
to the second aspect of the present invention, the closure may constitute a separate
or constitute an integral part of the bag as the two foil layers may constitute
two separate foil layers of the bag or alternatively constitute integral parts of
the pair of walls of the bag.
The second set of joints which, as stated above, are characteristic
of the closure according to the second aspect of the present invention may, according
to alternaitve embodiments, be constituted by linear joints, curved joints, combined
linear, bend and/or curved joints, and may define a diverging, converging or tubular
inlet channel or a combined diverging, converging and/or straight inlet channel.
The dot-shaped joint which is, as stated above, characteristic
of the closure according to the second aspect of the present invention may, in accordance
with alternative embodiments be configurated as a circular, an eliptical, a square,
a rectangular, a polygonal or any other configurated joint or a combination of any
of the above joints or being composed of a plurality of individual microjoints.
The closure may, as discussed above, be constituted by
a separate component or constitute an integral part of the bag, similarly, the prolongations
or extensions of the two-layer foils defining the turned-in parts may, according
to alternative embodiments, be constituted by separate single-layer, two-layer or
multi-layer foils as the prolongations or extensions may be constituted by integral
parts of the two-layer foils or be constituted by separate foil layer parts joined
to the two-layer foils.
The closure according to the second aspect of the present
invention may be implemented as a separate component of the bag or as an integral
part of the bag, which bag may further have any of the features of the bag according
to the first aspect of the present invention.
The bag according to the first aspect of the present invention
and also the closure according to the second aspect of the present invention may
dependent of the application and in this context particularly the lifetime of the
bag defined as the period of time through which the bag being inflated with an inflation
medium, such as pressurized gas, is maintained in its pressurized state for fulfilling
its intentional purpose as a packaging and protection bag, be made from polymer
foil materials selected from two-layer polymer materials, such as PP, PVC, PV or
PE materials being LD, PE, HDPE or MDPE of a thickness varying from 10µm -
100pm or two-layer coextruded or laminated polymer foils exhibiting improved gas
impermeability properties. The combined, the coextruded or laminated polymer layers
may, apart from PE, include PP, PVC and PU materials. Alternatively, the laminated
polymer layers may include three or more layers exhibiting identical outer layers,
such as PE layers sandwiching an intermediate layer or intermediate layers of another
material or other materials.
The present invention is now to be further described with
reference to the drawings, in which:
- Fig. 1 is a schematic and perspective view of a first side or the upper side
of a first and presently preferred embodiment of an inflatable bag according to
a first aspect of the present invention, which bag is to be inflated for producing
a cushion or pillow and is shown in un-inflated state.
- Fig. 2 is a schematic and perspective view similar to the view of fig. 1 illustrating
the first and presently preferred embodiment of the inflatable bag in inflated state,
- Fig. 3 is a schematic and perspective view similar to the views of figs. 1 and
2 illustrating the inflated bag also shown in fig. 2 from the opposite side or the
- Fig. 4 is a schematic and perspective view of a detail of the inflated bag shown
in Fig 3,
- Fig. 5 is a vertical sectional view of the inflated bag shown in Figs. 2, 3
- Fig. 5a is a detail of the vertical sectional view of the inflated bag shown
in Fig. 5 illustrating a particular feature of the foil material of the bag, which
foil material is constituted by a two-layer foil,
- Fig. 6 is a graph illustrating a surprising property of the two-layer foil material
of the bag according to the first aspect of the present invention as compared to
a single layer foil bag and a foil layer bag having a foil layer of the same thickness
as the two-layer foil,
- Fig. 7 is a schematic and perspective view of a detail of certain tools for
the on-line production of inner weld seams within the inflatable bag,
- Fig. 8 is a schematic and perspective view illustrating a presently preferred
method of producing the inflatable bag according to the first aspect of the present
- Figs. 9a, 9b, 9c and 9d are schematic views illustrating alternative geometrical
designs or configurations of an inflatable bag according to the first aspect of
the present invention.
The present invention relates to a novel technique of providing
a cushion or pillow by means of an inflatable bag. In figs. 1, 2 and 3, a first
and presently preferred embodiment of an inflatable bag according to the present
invention is shown designated the reference numeral 10 in its entirety.
Generally, the bag 10 includes an inner chamber defined
between two outer two-layer foils, which chamber is inflatable through the application
of an inflation medium, such as atmospheric air, pressurized air or a non-toxic
liquid, such as water into the inner chamber. Preferably, the inflation medium is
constituted by a gas, such as atmospheric air or alternatively a non-aggressive
or substantially inert or truly inert gas such as nitrogen or alternatively helium.
In Fig. 1, the bag 10 according to the first aspect of
the present invention is shown in an un-inflated state and the inflated bag is shown
in Figs. 2 and 3.
The bag 10 is basically made from a two-layer foil material
web, such as a two-layer HDPE, MDPE or LDPE foil, each layer having a thickness
of 10 -100µm, such as 15, 25µ or 50µm. The two-layer foil material
web is folded into a four-layer structure defining two opposite two-layer walls
12 and 14. Between the walls 12 and 14, an inner chamber 16 is defined.
The inner layers of the two-layer walls 12 and 14 are provided
with extensions or prolongations or extensions 24, 26 shown in greater details in
Fig. 8 defining turned-in parts extending into the interior of the chamber 16, as
the prolongations or extensions 24 and 26 are folded from the inner layers of the
two-layer walls 12 and 14, respectively through folds 28 and 30, respectively. The
lower ends of the turned-in prolongations or extensions 24 and 26 are designated
the reference numerals 25 and 27, respectively. Alternatively, both layers of the
two-layer walls 12 and 14 may in alternative or modified embodiments be used for
the prolongations or extensions 24 and 26, respectively.
As is evident from Figs. 1-3, the two-layer walls 12 and
14 are joined together through a plurality of joints, which may be constituted by
glue joints or advantageously weld seams. Two major weld seams 18 and 20 extend
parallel with two outer edges 19 and 21, respectively, of the bag 10. Opposite to
the folds 28 and 30, a further joint 22 extends parallel with an outer edge 23 of
the bag, which joint 22 is joined to the two edgewise positioned joints 18 and 20.
Whereas the joint 22 joins the two-layer walls 12 and 14 together, the edgewise
positioned joints 18 and 20 also join the three ply two-layer structure generated
by the turned-in prolongations 24 and 26 in combination with the outer walls 12
and 14 together along joined sections designated the markings, i.e. along joined
sections 18' and 20', respectively. The joined section 18' continues into a transversal
minor joint 32 and similary, the joined section 20' continues into a transversal
major joint 34. Between the transversal minor joint 32 and the transversal major
joint 34, an inlet opening into the interior of the bag 10 is provided. The inlet
is designated the reference numeral 36.
The transversal major joint 34 continues into a further
joint 40 extending to a position juxtaposed the folds 28 and 30 and defines a three
ply two-layer area, in which a cut 38 is provided, which cut serves as a handle
4 for carrying the bag prior to or after inflation of the bag. The interior of the
bag defined between the two two-layer walls 12 and 14 is divided into five compartments
defined by two parallel joints 42 and 44 extending parallel with the joints 18 and
20 and further two joints 46 and 48, which are each composed of three straight line
segments and are located adjacent to the joints 22 and 34, respectively. The joints
46 and 48 serve, as is illustrated in Fig. 2, to provide two transversal cushion
parts, which may adavantageously support the person sitting on the cushion or pillow
along the femurs, whereas the joints 42 and 44 serve to provide three inflated parts
providing sitting comfort to the person sitting on the cushion or pillow, as the
three cushion parts may adapt to the contour of the posterior of the person sitting
on the cushion or pillow.
The inlet 36 of the bag 10 constitutes a self-closure inlet
which, however, as distinct from prior art self-closure inlets, such as prior art
self-closure inlets known from the prior art self-closure ice cube bags, such as
the ice cube bags described in
EP 0 264 407
EP 0 574 496
EP 0 616 948
EP 0 825 122
, which US patent is hereby incorporated in the present specification by
reference, or alternatively the self-closing inflatable bag known from applicant's
European patent application No. EP 1 311 441
published international patent application WO 02/04317
in that no outer closure pockets are provided as the self-closure function
is established in the inlet channel itself extending into the interior of the bag
For providing the self-closure effect in the inlet channel,
the inlet channel is provided by two parallel curved joints 48 and 50, which join
the prolongations or extensions 24 and 26 together without joining the prolongations
24 and 26 to the opposite two-layer walls 12 and 14. In addition, a dot-weld 52
is provided, which dot-weld 52 joins the two prolongations or extensions 24 and
26 to one of the two opposite two-layer walls 12 and 14, in the embodiment 3 to
the wall 12 facing upwardly in Fig. 1. Furthermore, for establishing the self-closure
function within the inlet channel delimited by the two curved joints 48 and 50,
a pair of transversal joints are further provided, one of which is shown in Fig.
1 and designated the reference numeral 54, which transversal joints, such as the
joint 54 join the turned-in prolongation to the adjacent outer two-layer wall, i.e.
joining the prolongation or extension 24 to the two-layer wall 12 and similarly
joining the prolongation or extension 26 to the two-layer wall 14. In the embodiment
shown in Figs. 1-3, the prolongations or extensions 24 and 26 are, as discussed
above, constituted by the one layer of each of the two-layer walls 12 and 14, however,
in an alternative embodiment of the bag shown in Figs. 1-3, each of the prolongations
or extensions 24 and 26 may simply be constituted by separate foil layers or alternatively
turned-in parts of the two two-layer walls 12 and 14, respectively.
As discussed above, the dot weld 52 joins the turned-in
parts or prolongations or extensions 24 and 26 to the two-layer wall 12 and serves
to provide a self-closure function by causing the air present within the interior
of the bag to establish a closure pressure against the prolongations or extensions
24 and 26 and further preventing air from leaking through the passage defined between
prolongations or extensions 24 and 26 and defined between the two curved joints
48 and 50.
In Fig. 4, a detail of the inlet part of the bag is shown
in greater details disclosing the sealing off of the inlet by pressing the prolongations
24 and 26 against the inner foil of the two-layer wall 12 through the presence of
the dot-weld 52. In addition, Fig. 4 discloses a particular feature of the bag 10,
as the turned-in parts of the one-layer, i.e. the inner layer of the two-layer walls
12 and 14 provide two free flaps outside the inlet delimited by the further parallel
transversal joints, one of which is shown in Fig. 4 and designated the reference
numeral 54, which flaps allow the user to obtain easy access to the inlet 36 by
bending the flaps apart and then blowing air through the inlet 36 or alternatively
introducing a tube or hose or similar element into the inlet 36 for allowing e.g.
pressurised air to be introduced into the inner chamber of the bag 10.
In Figs. 5 and 5a, a particular feature of the two-layer
structure of the bag 10 is illustrated in greater details as in Fig. 5 and also
in Fig. 5a, the two individual layers of each of the two-layer walls 12 and 14 are
shown highly exagerated for the purpose of illustrating the above feature. In Fig.
5a, a detail of a part of the wall 12 is shown in greater details comprising an
outer layer 12a and an inner layer 12b. Due to the bending and stretching of the
two layers 12a and 12b and the difference in the length of the two layers when stretched,
the outer layer 12a is stretched more than the inner layer 12b as is illustrated
in highly exagerated diagrammatic illustration in Fig. 5a by the presence of segments
of the two layers 12a and 12b, which segments are illustrating the original unstretched
corresponding segments of the two layers. It is contemplated that the difference
in stretching and consequently elasticity and strength of the two-layers 12a and
12b provide an improved overall mechanical strength of the two-layer structure as
compared to a single layer wall having twice the thickness of one of the two layers
12a and 12b.
This surprising effect is supported by the measuring results
illustrated in Fig. 6, which figure includes a diagram representing measuring results
obtained from three different bag embodiments. A total of five samples of each of
the three embodiments were tested. All embodiments had the same geometrical configuration,
namely the configuration of the bag illustrated in Figs. 1-3.
The first embodiment was made from a single layer 25 µm
PE foil and the measuring results for the five samples are presented by the graph
A. Similarly, the second embodiment was made from a single layer 50 µm PE foil
and the measuring results are presented by the graph B. Finally, the third sample
implemented in accordance with the teachings of the present invention, two-layer
PE foil, each layer having the thickness of 25 µm corresponding to a thickness
of the first embodiment of graph A, and the measuring results obtained by employing
the third embodiment made from the two-layer 2x25 µm PE foil are illustrated
by the graph C.
Each of the five samples of each of the three different
embodiments were exposed to a load until the sample in question exploded or otherwise
The drafts A, B and C of Figs. 6 demonstrate that a foil
having twice the thickness of a thinner foil does not generate twice the strength,
whereas a two-layer structure provides a strength at least twice the strength of
the corresponding single layer structure.
In figs. 7 and 8, details of a method of producing the
bag 10 is illustrated. In fig. 5, the reference numerals 1, 2, 3, 4, 5, 6 and 7
represent 7 distinct stages of producing the bag.
In the stage 1, a two-ply web is provided, comprising two
two-layer foils 12 and 14, connected through a fold 13.
In stage 2, turned-in prolongations or extensions 24 and
26 are provided by folding turned-in parts of the two-layer foils 12 and 14 towards
the fold 12, and the outer layers of the two-layer foils are cut off at the folded
or turned-in parts as indicated by a line 15.
In stage 3, the parallel weld seams 48 and 60 are provided
by means of a welding tool designated the reference numeral 100 in its entirety,
which tool is to be described in greater details with reference to fig. 7.
In stage 4, the transversal weld seam 54 is provided by
means of a further welding tool designated 100' and similar to the welding tool
100 used in stage 3 by joining the prolongation or extension 24 to the two-layer
wall 12 and a similar weld seam is provided between the prolongation or extension
26 and the two-layer wall 14.
In stage 5, a separation element 102 is provided for separating
the layer 14 from the turned-in protrusion 26 for allowing the dot-shaped weld seam
23 to be established by the application of heat to the three-ply structure including
the wall 12 and the two prolongations or extensions 24 and 26.
In stage 6, the weld seams of the bag 10 are established
by means of sandwiching welding tools 110 and 112 which welding tools are preferably
operated in a reciprocating operational mode allowing the individual bags 10 to
be welded one at a time, e.g. in accordance with a technique described in the applicants
published international patent application WO99/32840
Finally, in stage 7, the finalised bag 10 is cut from the
continuous previously processed bag by means of a vertically operated and reciprocating
knife 114 which web has been shifted through the stages 1, 2, 3, 4, 5 and 6.
In fig. 7, the separation and welding tools used in the
stages 3, 4 and 5 are illustrated in greater details. The tool 100 for the welding
of the inlet channel delimiting weld seams 48 and 50 is constituted by a substantially
L-shaped insulating element 102, which is constituted by an L-shaped insulating
element 104 and provided with two printed circuit board terminals 105 and 107, which
are connected to an external power source through two electric wires 106 and 108,
respectively. The L-shaped insulating element 104 is provided with an enlarged end-part
116 from which two resistor wires having the configuration of the weld seams 48
and 50 are depending from the lower side. The wires are designated the reference
numerals 118 and 120 and are interconnected through a short-circuiting printed circuit
board connection 121.
As will be understood, the printed circuit board terminals
105 and 107 together with the short-circuiting printed circuit board connection
121 provide a series connection of the two resistor wires118 and 120 which are powered
by the external electric power source connected to the wires 106 and 108. The plate
116 is pressed into contact with the turned-in prolongations or extensions 24 and
26 by the application of pressure from above by means of a pressure plate 122, which
is journaled on two linear guides 126 and 128 and which is caused to reciprocate
vertically by means of a piston 130. At the lower side of the plate 122, a soft
surface padding is provided.
Opposite the vertically reciprocating plate 122, a separation
plate 132 is provided, which separation plate is positioned between the turned-in
prolongation 24 and the outer wall 12. It is to be realised that the plate 116 separates
the turned-in prolongations or extensions 26 from the inner wall 14 preventing the
inner wall 14 from being welded to the turned-in prolongation 26 as the separation
plate 132 similarly prevents the turned-in prolongations or extensions 24 from being
welded to the outer wall 12.
Below the separation plate 132, a plate 134 of the frame
of the apparatus is positioned.
From an edge part of the plate 116 opposite to the I-shaped
insulating element 104, a teflon band 103 extends, which teflon band is also shown
in fig. 4 serving the purpose of separating the wall 14 from the turned-in prolongation
26. The separation element 102 further serves the purpose of separating the wall
14 from the turned-in prolongation 26 for preventing the foil materials of the wall
14 from being welded to the turned-in prlongations 26 and 24 and further the wall
12, as heat is applied from below to the outer surface of the wall 12 by means of
a heating tool 124 for providing the dot-shaped weld seam 52 causing the turned-in
prolongation 24 and 26 to be welded to the wall 12.
In Figs. 9a, 9b, 9c and 9d, four alternative embodiments
10', 10", 10"' and 10IV of the inflatable bag according to the first
aspect of the present invention are shown, respectively. Generally, the alternative
embodiment 10'-10IV of Figs. 9a-9d illustrate the multiplicity of possible
alternative configurations of the inflatable bag according to the present invention
and since the illustrations are self-explanatory, no detailed discussion of the
embodiments are presented here.
A prototype version of the first and presently preferred
embodiment of the bag 10 according to the first aspect of the present invention
was made from two-layer LDPE foils each layer having a thickness of 25 µm LDPE.
The outer walls 12 and 14 measured 570 mm x 370 mm. The turned-in prolongations
or extensions 24 and 26 defined a length from the upper edges 28 and 30 of 120 mm.
Although the present invention has been ascribed above
the refernce to specific embodiments of the bag and also specific embodiments of
the closure, it is of course to be contemplated that numerous modifications be deduced
by a person having ordinary skill in the art and modifications readily perceivable
by a person having ordinary skill in the art is consequently to be construed part
of the present invention as defined in the appending claims.