CA1102454A - Fluid filled beds and the like - Google Patents

Abstract

FLUID FILLED BEDS AND THE LIKE

ABSTRACT OF THE INVENTION

Apparatus and method are disclosed which pertain to inflatable structures useful as air beds and the like. Shape and load con-trol are facilitated by a plurality of bladders that are located within an inflatable chamber of the structure and are joined to opposed imperforate walls thereof. The bladders are provided with vents which lend to the interior of the chamber, and upon inflation of the structure and resultant separation of the opposed walls of the chamber, the bladders are caused to extend from a flattened state, become filled with the fluid used for inflating the structure, and assume a roughly cylindrical con-voluted configuration. Being made of a flexible, substantially non-extensible material, such as vinyl plastics, there is a limit to which the bladders can extend, and further vertical separation or lateral shifting of the attached opposed walls is thereby restrained. When the bladders are provided with vents, they "breathe" when a physical load is applied to the inflated struc-ture or removed from it, hence, regulating resiliency by means of an "air spring" effect.

Description

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1 ¦ BACKGROIJND OF TH2 INVENTION
21 The present invention pertains to inflatable structures and more 3 I particularly to load supporting structures where the function 4¦ is to provide a measure of resiliency or a spring effect.
51 Accordingly, the pxesent invention can be used to advantage in 61 the construction of air or water beds to control the shape and 71 resiliency thereo, ~
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9¦ Air beds and -~ater beds have been marketed with various types 10¦ of connections between the top and bottom sheets that function 11 as the springs or ties used in conventional bedsprings or mattre-12 sses. Exemplary connections or ties between imperforate upper 13 and lower plastic walls of prior fluid-filled beds include in-14 flatable cylinders or beams as shown in Nail's UOS. Patent No.
1~ 3,705,42g, and zig-zag sheets as shown in ~;elzer's U.S. ~atent lo ~0. 2,703,770. The c~-linders and beams disclosed b~ ~;all serve 17 as ties between the top and bottom s;eets of ~he structure, but 18 are molded to a generally cylindrical or rectangular shape and, as such, ca.~not readily assume a smootnly flatt~ned configuration when the structure is deflated, thus hindering the coll~pse 21 thereo~ to â neatly folded configuration having minim~m ~olume.
22 This pro~lem is overcome to some e.~tent by use of one or more 23 ties in the form of zi~-zag sheets between the upper and lower sheets as is shown by Melzer, but this increases the cost of materials, construction is more complex, and there is limited

2~ choice of the pattern of "tufting" that can be provided. In X7 acdition, the walls of the air cavities in ~elzer's structure are ' ~ __ 29 __ : 30 31 -2- ~ -:~` .l ~ 2~S~
1 ¦ interconnected with each other, as are the air cavities them-: 2¦ selves, and snape and load control functions are not equivalent ¦ to those provided by use of individual, free-standing pockets ¦ located within an outer inflatable chamber. Smoothly flattened bladder configurations are known to have been used in connection 61 with inflatable toys and the like, but they included undesirable 71 perforated top and/or bottom walls, permitting air to free~ly 8 enter the bladder from the outside of the device.
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1 SUM~L~RY OF THE INVENTION
2 A primary object of the present invention is, therefore, to over-

3 come the aforementioned problems and disadvantages associated

4 with prior inflatable structures.
6 One particular object is to provide an inflatable structure with 7 imperforate top and bottom walls having improved provisions for 8 shape and load control upon inflation, but which can be totally 9 collapsed and thus fully flattened upon deflation.
',` 10 11 Another object is to provide an easily constructed inflatable 12 structure such as an air bed or water bed, having an inflatable 13 chamber with imperforate outer walls that are tied together by 14 means of a plurality or independent bladders that are in a flat-tened state when the structure is deflated, and which assume a lZ generally cylindrical shape when the structure is inflated.

18 Still another object is to provide such an inflatable structure 19 having "pancake" bladders therein which become e~tended for shape and load control of the structure when it is inflated, and 21 which flatten out like pancakes when the structure is deflated.

23 Other objects and advantages of the present invention will be~
24 come apparent from the following description, the drawings and 27 ~ the ap nded cl~ims.
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Accoxding to the inven~ion, an in~latable structure is provided which comprises an inflatable chamber with opposed imperforate walls formed of substantially non-expansi~le air impervious material and which are progressively separable by continued inflation of the chamber.
A bladder formed of a flexible substantially non-expansible material is located within the chamber and is joined to both o the opposed walls ~hereof on a bladder axis. The bladder is axiaLly extensible from a flattened state and is convolutedly inwardly collapsible to~ard the axis upon progressive separation of the opposed walls of the chamber.
A plurali~y of such bladders, spaced apart from each other, can be employed in inflatable structures intended for use as air or water heds.
In accordance with one aspect of the invention there is providad for use in a waterbed mattress made of flexible, water impervious sheet plastic material: a wave damping bladder for attachment inside the waterbed mattress and comprising two juxtaposed layers of flexible thermoplastic sheet material, said layers being welded together along the peripheral regions thereof~ the central regions of the layers being unattached whereby said central regions, when attached to the mattress, separate as the mattress is filled with water, thus to move the layers from a flattened state to a three-dimensional biconical shape.
In accordance with another aspect of the invention there is provided for use in a wa~er~ed mattress made of flexible, water impervious sheet plastic material: a wave damping bladder for attachment inside the waterbed mattress and comprising two juxtaposed layers of flexible thermoplastic sheet material, said layers being welded together along the peripheral regions thereof, the central regions of the layers , ~
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Z~i4 ~ being unattached whexehy said central regions, when attached :~ to the mattress, separate as the mattress is filled with water, thus to move the layers from a flattened state to a J~ three-dimensional con~oluted, in~ardly collapsed shape.
The presently disclosed inflatable structure thus ; comprises an improvement for tying the opposed imperforate walls of the inflatable structure together and, when desired, for controlling resiliency of the s~ructure. Fabrication of the s~ructuxe includes the step o~ confrontingly aligning two sheet members of a 1exible substantially non-expansible material, joining the perimeters of the sheet members ~ :.
together, and thereby forming a flat "pancake" bladder. The hladder thus formed is thereafter placed between the opposed -~ walls of the in~lata~le chamber of the structura and is aligned so that each sheet member thereof confronts one of the - opposed walls. Each of the oppvsed walls of the inflatahle chamber is then joined to the sheet member of the bladder that confronts it~ and with the joint therebetween being located inwardly of ~he perimeter of the sheet member.

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1 ¦ BRIEF DESCRIPTION OF THE DRAI~I~GS
2 ¦ A detailed description of the invention will be made with re-3 ¦ ference to the accompanying drawings wherein like numerals 4 ¦ designate corresponding parts in the several figures. ThesP
~ ¦ drawings, unless described as diagrammatic or unless otherwise ; 61 indicated, are to scale.
~` 7 ` ~ 8 FIGURE 1 is a perspective view, partly in section, of an air 9 bed constructed in accordance with the present invention.
~' ` 10 ~ 11 FIG. 2 is a somewhat enlarged elevational view, in section, of : 12 the air bed of FIGVRE 1, and illustrates the aix bed while 13 deflated and during an assembly step wherein one of the deflated 19 "pancake" bladders is being joined to the opposed walls of the inflatable chamber of the air bed by sealing with a heated ring.
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17 FIG. 3 is a somewhat enlarged elevational view, in section, of 18 the air bed of FIGURE 1, and illustrates the "pancake" bladder in 19 an extended, cylindrically convoluted state, following inflation of the air bed.

22 FIG. 4 is a downward view of the structure shown in FIG. 3.

24 FIG. 5 is a perspective view illustrating sealing of the peri-meters of the two confrontingly aligned sheet members of the 26 "pancake" bladder shown in the drawings.

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l FIG. 6 is a somewhat enlarged downward view, partly in section, 2 of the flattened 'Ipancake" bladder located between the upper and 3 lower opposed walls of the air bed shown in FIGS. 1-4.

FIGS. 7 and 8 are perspective views of the "pancake" bladder 6 following perimetric sealing and perforation of the sheet members 7 thereof, and further illustrating insertion of a heat insulating : paddle into the bladder prior to ring sealing of the sheet 9 members to the opposed walls of the air bed.

11 FIG. 9 is a somewhat enlarged perspectlve view showing sections 12 of the upper and lower opposed walls of the air bed of FIGS.
13 1-4 and a deflated "pancake" bladder therebetween, just after 14 sealing of the sheet members of the bladder to the walls and subsequent to removal of the heat insulating paddle from the Z~ cavity f th~ bladd-r.

~; Z' . 32 _7_ DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
2 The following detailed description is of the best presently con-- 3 templated mode of carrying out the invention. This description 4 is not to be taken in a limiting sense, but is made merely for purposes of illustrating the general principles of ~he invention 6 since the scope of the invention is best defined by the appended ~ ` 7 claims.
`;; 8 9 The term "inflatable structure" as used herein is intended to 13 mean any structure that is inflated by means of a suitable Lluid ~-; 11 such as air or water, and is intended to include air beds, air 12 mattresses, water beds, inflatable cushions, pillows or furniture , 13 and also such structures as inflatable watercraft, aircraft, 14 chutes, slides, toys and the like.

; 16 The opposed walls of the inflatable chamber of the present struc-17 ture are formed from a flexible, substantially non-expansible 18 air impervious material auch as a thermoplastic resin~ The term 19 "substantially non-expansible material" as used herein is intend-ed to mean a material that has a relatively limited degree of 21 stretch with respect to that exhibited by a non-reinforced 22 rubber. Examples of such materials include thermoplastic poly-23 meric substances that are strong, yet flexible at room tempera-24 tures, and a preferred tnermoplastic material for construction of the present structures can be selected from commercially avail-26 able polyvinyl chloride compounds.

28 In FIG. 1, an inflatable structure is represented at 1, and - comprises an in.perforate upper wall 2, and an opposed perforate lower wal~ 3, which along with sidewalls 4, enclose an air 31 chamber 5. The upper and lower walls are thermally bonded to 32 __ ` 11 -8-~ 51L

1 ¦ the side-wall seams 6 and 7, and a conventional air valve or - 2 ¦ valves 8, are installed in a:wall or walls as means for injecting 31 air or water into the chamber 5, and for the subsequent emptying thereof. Bladders constructed in accordance with the present ~¦ invention are represented at 9.

71 As previously indicated, the upper and lower walls 2 and 3 are 81 made of a flexible, substantially non-expansible air impervious ;~ ¦ material, such as polyvinyl chloride, and the same type of mater-101 ial can be used for constructing the sidewall 4 and the bladders 9. It will be understood, however, that different materials can be used for the upper and lower walls 2 and 3, the sidewall, : 13 and the bladders when such is preferred.
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1~ Referring to FIG. 5, in this example, each of the bladders 9 is 1~ formed from two circular sheet members 10 and 11, which have been 17 punched or otherwise cut from an elongated sheet of thermoplastic 18 resin. Thereafter, the two circular members are confrontingly 19 aligned, one over the other, and placed between two heated rings 12 and 13 for sealing of the edges of the members by displacing 21 the rings toward each other so that the edges of the sheet mem-22 bers 10 and 11 are pressed together between the heated ring sur-23 faces 14 and 15. Softening of the plastic all the way around the 24 perimeter 15 of each circular sheet member is thereby effected, and there is a welding or fusion of the softened plastic which 26 results in the joining of the two members at their perimeters to 27 form a seam 17 (FIGS. 2, 3, 7 and 9~, but there is no fusion and 28 joining of the pla~tic sheet members 10 and 11 inwardly of this 29 seam. A flat i'pancake" bladder comprising the per~pherally join-3l~ ed c cular sheet members is thereafter rec~vered, and is :
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l subsequently installed bekween the upper and lower opposed walls 2 ~ and 3 of the air bed 1. Other methods of forming the bladder 3 9 may utilize a pair of overlying sheets which are fused together 4 in multiple, spaçed ring patterns and the patterns are cut out ~ just ou~side the fused ring.

7 The bladders are provided with venting means so that they can 8 become filled with the fluid injected into the chamber 5 during inflation of the structure. Accordingly, one or both of the sheet members 10 and ll can be perrorated to provide one or more ll openings 18, therein before or after forming the perimetric seam 12 17 of the bladder. after forming the openings 18, the bladder 13 can be attached to the upper and lower walls of the air bed by 14 thermal sealing in a manner similar to that employed for peri-metric sealing of sheet members 10 and ll. Refering to FIG. 2, l~ the flat, "pancake" bladder 9 is inserted between the upper and 17 lower walls 2 and 3 of the structure for~join~ing of these walls 18 with the bladder by heat sealing through use of heated rings l9 l9 and 20. An insulating member is emplaced wlthin the bladder, and thus between the sheet mer~ers thereof, to prevent heat seal-21 ing of the sheet members to each other during the sealing there-22 of to the outer walls of the structure. As shown in FIGS. 7 and 23 8, the insulatiny member can be in the form of a metal plate 21, 24 and can be equipped with a handle 22, or other appropriate hand-ling means, to facilitate insertion of the plate into the bladder 26 cavity 23 and subsequent removal therefrom. Accordingly, the bladder 9 can be provided with a slit 24 in its wall to permit 28 insertion and removal of the plate 21, and it will be appreciated 29 that the handle 22 also serves as an aid in properly locating th~
plate 21 with respect to the bladder and the heat rings l9 and 2G
31 when the bladder is placed between the walls 2 and 3 for sealing 32 thereto.

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; 1 Once a bladde~ 9 and an emplaced plate 21 have been positioned 2 in a desired location between the opposed walls 2 and 3, and ~he 3 bladder and the walls have been placed between the heated rings 4 19 and 20 with the bladder centered with respect thereto, the ~, 5 heated rings are then brought toward each other to compress the bladder sheet members 10 and 11 against the walls 2 and 3 to ~; 7 effec~ the joining thereof. Accordingly, sufficient heat and 8 pressure are applied by means of the heat rings to effect welding 9 or fusion of the thermoplastic walls of the bladder and the walls 2 and 3, and this results in formation of ring seals 23 and 11 26 at the sites where the fusion occurs. Once the formation of 12 the ring seals is completed, the heat rings 19 and 20 are separa-13 ted from each other as shown in FIG. 2 and plate 21 is withdrawn 14 from the bladdex through slit 24, as shown in FIG. 9. Thereafter other like bladders are sealed to walls 2 and 3 in the same fashion as previously described. The foregoing provides a manu-17 facturing method which is relatively simple, reliable and in-18 expensive.
,' 19 As previously indicated, the bladders 9 are aligned on a bladder 21 axis which is generally perpendicular to the opposed walls 2 and 22 3 of the inflatable structure. Such an axis is illustrated by 23 line A-A in the drawings. A plurality of bladders can be aligned 24 on an equivalent number of axes arranged in any convenient patt-ern to provide various air spring effects or "turfing" patterns 26 as may be desired.
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1 1 FIGS. 2, 6 and 9 illustrate the "pancake" bladder 9 in a flatten-2 ed state, i.e. the configuration of the bladder w~en the struc-- ture 1 is deflated. FIGS. 1, 3 and 4 illustrate the bladder in an extended, convolutedly in~ardly collapsed state followins in-~ flation of the air bed by injection of a fluid into the inflat-- able chamber 5. As can been seen from the drawings, the bladders ` 7 are axially extensible from the flattened state and convolutedly inwardly collapsable toward the aixs A-A upon progressive separa-9 tion of the opposed walls 2 and 3 of chamber 5 during the infla-tion thereof. More specifically, as the walls 2 and 3 move apart ; 11 from each other during inflation of the air bed, the bladder ~- 12 sheet members 10 and 11 are caused to move apart from each other 13 in opposite directions along the axis A-A, thereby forming a 14 bladder cavity 23 between the sheet members which fills with the fluid being sucked into chamber 5 through the openings 18 and 1~ slit 24. As further separation of the walls 2 and 3 occurs by 17 continued inflation of chamber 5, the sheet members 10 and 11 18 assume a biconical configuration in alignment with axis A-A, and eventually the sheets partially collapse inwardly toward the axis to form convolute folds 27. When this convolutedly inward colla-21 pse of the bladder members has progressed to the maximum degree, 22 the bladder is essentially no longer axially extensible, and it 23 thereby restrains further separation of the opposed walls 2 and 24 3.

26 Each of the bladders 9, therefore, has an axial extension limit . 27 equivalent to a maximum desired separation distance between the ; 28 opposed walls 2 and 3 when the air bed has been fully inflated.
29 This axial extension limit is established by cons~ructing the bladder s~ that the difference between ~,he diameter of each of 31 the sheet members 10 and 11 and that of its respective ring seal 32 25 or 26 is approximately one-half of the desired separaticn Il -12-24L 5i 4 ~?

1 distance between the opposed walls 2 and 3 when chamber 5 has :;t 2 been fully inflated. The seal rings 25 and 26 can, nonetheless, 3 have any diameter selected to provide both satisfactory strength 4 of attachment to the walls 2 and 3 and a desired appearance for esthetic purposes. Where preferred, the attachment of the bla-dders to walls 2 and 3 can have other than a ring or circular 7 confi~uration, and regardless of the shape, size and nature of ~- 8 the joint between the bladders and the opposed walls, the max-imum separation distance between the walls can be increased by ~' 10 use of bladder sheet members 10 and 11 of a larger diameter, 11 and can be decreased by use of sheet members having a smaller 12 diameter. More specifically, the extension limit of the bladders 13 can be increased or decreased by selectively increasing or de-14 creasing the sheet members 10 and 11.
, ' 15 lZ As shown in the drawings, each of the bladders g is provided with 17 venting means, e.g. openings 18 and the slit 24 functions as 18 venting means whereby the bladder cavity 23 becames filled with 19 the fluid injected into chamber 5 of the structure 1 during the inflation thereof, but it will be understood when a bladder i5 21 thus filled, it nonetheless provides an "air spring" effect even 22 though fluid is partially ejected from its cavity back into the 23 chamber 5 when a load is placed on the alr bed and causes it to 24 become compressed. Such occurs as a result of the fluid in chamber 5 being under pressure, hence causing a retarded dis-26 charge of fluid from the bladder cavity. In a similar fashion, 27 the cavity does not immediately refill after a compressive load 28 is removed from ~he air bed, and the bladders thus "breathe"
29 upon application and release of pressure on the structure 1.

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',',`.' ; 1 It will be appreciated that the rate at which the bladders 2 breathe is dependent upon the number and si2e of openings such 3 as 18 and 24, and that both the number and size of the openings 4 is subject to variation depending on the degree of resiliency and load control desired.
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7 As shown in FIGS. 1, 3 and 4, the structure 1 is shown to be in-8 flated with the bladders 9 extended along axis A-A to their max-9 imum limit, and whereby the bladders have assumed a convoluted cylindrical configuration. Accordingly, the opposed walls 2 and 11 3 are restrained by the extended bladders from further separating 12 from each other, which also being xestrained to a considerable 13 degree from lateral displacement. Shape control is thus provided 14 by the bladders, and an "air spring" efect ror load control is also provided when the bladders are suitably adapted to provide 1~ such an effect.

18 It should be re-emphasized out that the present bladder constru-19 ction is particularly advantageous from the standpoint of ease of manufacture as well as convenient storage, i.e. upon dis-21 charging the fluid from chamber 5, the bladders return to a flat 22 "pancake" configuration as shown in FIG. 2 so that the entire 23 deflated structure becomes quite flat for folding and rolling in-24 to a volume approaching the smallest possible size.

26 An infla~able structure that fulfills the previously stated 27 objects has now been described in detail, and since the descrip-28 tion has not included details on all conceivable embodiments 29 thereof, it will be understood that other embodiments will be-come apparent which are within the spirit and scope of the in-31 vention defined in the following claims.
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Claims (6)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. For use in a waterbed mattress made of flexible, water impervious sheet plastic material: a wave damping bladder for attachment inside the waterbed mattress and comprising two juxtaposed layers of flexible thermoplastic sheet material, said layers being welded together along the peripheral regions thereof, the central regions of the layers being unattached whereby said central regions, when attached to the mattress, separate as the mattress is filled with water, thus to move the layers from a flattened state to a three-dimensional biconical shape.

2. The bladder as set forth in claim 1 in which said layers are essentially circular, the edges of the circular layers being welded to each other.

3. The bladder as set forth in claim 2 in which at least one of said layers has an opening therein sufficient in size to permit insertion and removal of a heat insulating plate between them whereby the area of welding of the layers is controlled.

4. For use in a waterbed mattress made of flexible, water impervious sheet plastic material: a wave damping bladder for attachment inside the waterbed mattress and comprising two juxtaposed layers of flexible thermoplastic sheet material, said layers being welded together along the peripheral regions thereof, the central regions of the layers being unattached whereby said central regions, when attached to the mattress, separate as the mattress is filled with water, thus to move the layers from a flattened state to a three-dimensional convoluted, inwardly collapsed shape.

5. The bladder as set forth in claim 4 in which said layers essentially circular, the edges of the circular layers being welded to each other.

6. The bladder as set forth in claim 5 in which at least one of said layers has an opening therein sufficient in size to permit insertion and removal of a heat insulating plate between them whereby the area of welding of layers is controlled.