CA1182932A - Waveless waterbed - Google Patents

Abstract

WAVELESS WATERBED

ABSTRACT

THis invention relates to waterbed mattresses. Waterbed have been beset with a major disadvantage in the tendency for wave motion to be created in the mattress. Wave motion has been reduced in the prior art by the use of baffles, foam toppings, and gels. However, such solutions involve high cost in manufactuaring and shipping and pose difficulties to consumers who wish to empty, reposition, and refill their waterbeds. The present invention overcomes these deficiencies of the prior art by providing a waterbed mattress having a slab of open celled foam substantially submerged in, yet partially suspended above the upper surface of, the liquid fill of the mattress. The waterbed mattress of the present invention retains the positive qualities of bouyant support and comfort of conventional waterbed mattresses, and reduces the undesired wave motion often created within the mattress.
other embodiments of the present invention include a waterbed mattress having a large number of open celled foam particles which will be substantially submerged in, yet partially suspended at the upper surface of, the mattress's liquid fill, such particles being either enclosed in a gauze-like sack or unenclosed within the mattress. The present inven-tion may be incorporated in waterbeds or other body supporting furniture such as chairs and couches in which a liquid fill medium is used.

Description

3,~
AVEIESS WA~ERBED

TE;CHNIC~L FIELD
.
mis lnven~lon relates to waterbed m~ttres~a~
BACKG:ROUND OF THE PRIOR ART
Slnce the late lg6o~s.~ when waterbedæ were ~r~t :tntroduced, waterbeds have been ga~ning increas:lng accep-tan~e, It ha3 been recogniæed that waterbed~ provide dimen~ions o~ comf'ort and bodlly support not available ~rom conven~ional ~ner ~pr~g or foam mattre~B beddlng ~ystem~, Waterbeds have also become ~vored ~or thelr therap~utic and o~her user qu21it:~es.
However, waterbeds have been beset with a ma~or di~advantage, Thl~ di~ad~anta~e ~ the kendency ~or wave 15 ~otlon to b oreated in the waterbed mattre~s. Wave motion ~n the mattre~ ca~ make u~er~ o~ the waterbed uncom~ortable~ and con~umer fear o~ "~ea~-lokne~ ha~
inhlbited the acceptanoe o~ waterbed~.
Heret~fore, att~mpts have been made to provide 20 a waterbed mattre~s tha~ wou~d retard or d~mpen wave motion~ The ~u~e~ 1979 ~ssue o~ Cali~Drnia Buslne~ ln an article by Bob Gilberk ent1tled "Taking the Plunge"
(p. 54), report~ at page 60 that lt wa~ hoped "hybr~d"
bed3 would ~olve thl~ wave mok~on problem. A hybrid bed 25 ~ompri~e~ a w~ter m~ttre~ wlkh a foam topping placed o~er the n~ttre~. Unfortunately, hybr~d beds are a~ ~u~
ceptlble to wave mot,1on a~ conve~tlo~al wa~erb~d~9 The ~ame articl~ reporks, al~o ~k ~e Go, th~k att~mpt~ ko aah~eve motio2l1e~ characterl3t:1Gs includ~
30 puttln~ p~astic ba~ le~ in~ide the water~ed mattres~
and "~loatlng a ~ell on the kop hal~ o~ a ma~tr~s~
~eparated ~rom water on the bottom hal~ by a vlnyl ~he~t~"
Another recenk attempt to reduce wave motion includ~s cQn~truction o~ baffle chambers wikhin the 35 ma~tres~ The chamber3' slde panels are welded to tho mattre~s' bot~om sh~et. ~he chambers' tops~ connected to the upper edges o~ the ~de panels, are made Or ~oam d allowed ~o float ~ree Or any contact wlth the mattre~3 in an e~ort ko ~orm an in~ernal break~ater~
The above discus~ed aktempt~ to reduce wave

-2 -motio2~ hsYe met wlth varlous degre~ Or 8u¢~e~8, Un-~ortur~tely9 whatever degr~ Or wave damp~nlng a~h~ved by ~u~h ~y~tem3 ha~ o~ten been ~ore than 0~8et by ~
~re!a~ed C0~8 ~nd compleacitte~ Or manur~c~ure. Mor~over, 5 ~ h ~yotem~ are o~ten expens~v~ to ~hlp" a~ad th~y pose d~r~icultie~ to co~umers who wish to empty,~ reposlkl~alJ
snd r~111 khelr waterb~d~D In th1~ ~gs.rd~ ~qa~r~d ~y~t~ u~in~ ~psclal gel~ or addl~v~s oause addi~
al pr~ m3 and ~xpen~e~0 Uhlt~d State~ Pate~k No. 0 3,7~484 ar~d 3,736"604 l~u~d to ~. Car~onJ Jr., ~nd to SD Tobonlck and A.
- Saminof~" r~ ctlvely, dl~close hybrid type ~terb~ds, Waterbed mattre~seY, compr~g bafrle~ to dampen wave motlon are disclo~ed ~n C. Mollura~ Unlted 5takes Patent No. 4,14ï,T70 and ~. Foge1 l~ Unit~d Skat~s Pat~nt No.
4,152,796. United Stat~ Patent No. 39349J953, issu~d kD R. Conaway and J. Sp~dler di~clo~es ~ ~nk wlth a ba~fle system ln~erted to prevenk 310shing of liq~lid ln the t~k.
United State~ Patent No. 3.,,7489669, ls~ued to F . Warner, di~closes a waterbed matkre3a comprl~ ; fluld imp~ious cella distr~buted ~hroughout the m~ttre~s to dî~pia~e liquld whloh would otherwlse be r~quir~d to ~ill ~he mattr~s~, thu~3 r~duoin~; thc total w~ ;ht o~ the ?5 m~tt~ B. Unit0d 5tate~ ~a~ent No. 3~787~908J ~c~ued to ~ ck ~nd N. Sw~ny, al~o ~lscloa~ a lla~uld ~llleâ
mattr~ haY~ w den~lty oellul~r ~rti~ïe~ ~u~pe~d~d throughout th~ llquid in ord~r to redu~e the weight o~
the ~ d mattress~ llular par~icl~s al~o im~

3 ps~ov~ th~ ulat~v~ propert~s Or the llqu~d ~111.
Beck et al al~o teach add~ a vi~oo~lty modirier to th~
llqu~d ~ill to improve the waterbed mattre~se~ ' dimsrl~iorl;
al stablllty ~haracteris~icsO
Unlted States Pa~rlt No . 3, 5B5, 356, ~sau~d ko 35 C. Hall~ di~clo~es produc~g a dampen~ng e~qct by plac~g a suitable ~oli~ material ln suspen~ion ln the ~luid wlthirl the m~lttreE18o Hall teache~ th~ ground or ~hredded ~yro~oam at a volume ratlon o~ about one to three to water producea a dampPnin~s e~eck,. Hall al~e teaches *

~;, Trademark replacing the stYrofo~m*by starch or other materlal which wlll ~tay in suspension in the fluld. An alternative embodiment is also shown by Hall, wherein small blocks of a material such as styrofoa~ float upon the entlre surface of the fluid. Hall teaches that the blocks rub against each other and thelr reaction wlth the fluld provides lndependent suppDrt for all partB of a body posit~oned on the waterbed mattress.
D. McGrew, in United States Patent NOn 3,8lO~265, teaches dampening wave motion by addlng a water soluble viscosity increasing agent to the liquid fill of the mattress McGrew also discusses the preference that the water mattress not be secu~ed to the frame, especially along the upper marglnal surface of the mattress to lnsure preservatlon of even bouyancy and preventlon of a shear-producing hammocking effect. For thi9 purpose the upper surface of the mattress may carry some ~lack as provided by a plurallty of pleats in the upper mattress surface. Additlonally, a foam rubber or other elastic pad may be floatably posltloned on the upper mattress surface for added comfort or temperature compensatlon The systems described by the above dlscussed patents have not achieved a satisfactory wave dampening effect without compromising the qualitles expected of convention~l waterbedsn Moreover, such systems bear t~le disadvantages d-1scussed earlier; namely~ lncreased costs and complexltles of manufacture, increased costs Or shlpp-~ng, 1ncreased diff-l.culties -ln emptylng and refilling, and increased maintenance costs.
~RIEF SU~RY OF THE INVENTION
~ . _ The present invenkl~n is a ~aterbed mattress havlng a slab of open celled foam substantially submerged in, yet partially suspended above the upper surface of, the liquid flll of the mattress. The waterbed mattress of the present invention retains the positive qualities of bouyant support and comfort of conventional waterbed mattresses, and reduces the undesired wave motion often created within the mattress. Other embodlments of the present invention include a waterLed mattress having a * Trademark q~ J

large number o~ open celled ~oam partlcles wh-lch wlll be ~uhstantially submerged ln, yet partlally su~pended at the upper sur~ace Or, the mattress's liquid ~ill, such particles be-lng elther enclo~ed -ln a gauze~llke sack or unenclo~ed w~thin the mattress. The pre~ent inventlo~
may be lncorporated in waterbeds or other body ~upportlng furnJLture such as chalr~ and couches ln whl¢h a llquld f-lll medlum 1~ used.
BRIEF DESC~IPTION OF ~HE DRAWINGS
F-lgure 1 is a cutaway, kop view of a~ embodiment o~ the pre~ent invention.
~ lgure 2 is a slde sect~onal view o~ ~he pre~ent lnventlon taken along line 2-2 o~ Figure 1, Fi~ure 3 1~ a cutaway, top view of ~nother embodimenk o~ the pre~ent invention, Figure 4 is a slde~ sectlonal view of the present inventlon talcen along llne 1~_4 o~ Figure 3, Figure 5 i~ a cutawa~ top vlew o~ sti:Ll anokher embodimenk of the present lnventlon.
Figure 6 is a slde~ ~ectional view o~ the pre~
ent invenkion taken along line 6-6 of Flgure 5.
DET~ILED DES RIPTION OF THE INVENTION
In the following dlscussion3 the ~ams numeral will deslgnate ll~e elements throughout the drawin~, For example, in Figures 1 through 6, wh:Lch llluskrate preferred embodlments of thls inventLon, the upper and lower she~ts of the waterbe~ mattre~s are deslgnated, respectively, by numbers 11 and 12 ~hroughout, Whlle thi~ d~scrlptlon o~ten refers to '~ater" as the llqu:ld fill ~or the ~vented waterbed mattress, lt should be unders-tood tllat the present invention contemplate~ other liqu~d~ such as aqueous composltions containlng germl-cide~, fung-lcides, vlscosity modifiers and/or add~tives for enhanced heat transfer.
The present inventlon lncorporates many o~ the elements of conventlonal waterbed technolo~y. Sheet~ 11 a~d 12 are typicall~ vinyl sheets ~olned together b~ a heat s~al 14 to form a flu-L~ retaining compartmentO The mattress has a standard valve 16 to allow for the filllng ~r ~ ?3.~

and empty~g of the mattix'e98~
Re~errlng to Fl~ ur~ nd 2., the dla~rltlc f~eature ~ the pre~ent lnventlon can be ~een. Wat~rb~d mat'cre~ or bladder 10 comprl~e~ an open c~lled roam ~lab 18 . Th~s ~lab 1~ d:I ~po~ed between ~hee~3 11 arL~ 12 b~for~ they are ~ealed together. Tne ~oam elab 1~
dimensloned ~o 1;hat lt sub~antially ocoup~es the leng~h and width o~ the waterbed mattress. 'rhe thlch~ o~
~oflm ~3lab 18 i~'pre~erably betwee~ L10 t;o 60 percent o~
10 the depth o~ the ~llled mattress. For exampl~, if th~
~illed n~ttre3s 1 ~ 6 ) lnche3 deep t ~oam ~lab 18 should pr ~erably be about 2~4 to 3,6 lnche~ thlck to ob~ain optimum re~ults.

1~

ThP ce 11 Or the f~m are interconrlected. Thus, water flows into and 20 fl 119 all the cells o~ that port~ on o~ the ~oam whieh i8 gubmer~;ed.
Foam slab 1~, beside~ belng capable of be~
~illed wlth water, i~ a ~oft resilient material, capable o~ ~lRxing under body weight. I~he speci~ic gravlty o~
25 the ~oam i~ ~ueh that lt remaln~ sub~tantially submerged in, yet partially ~ pend~d at th~ ~urraoe o~, the llquid when the maktre~ 3d (l.e., le99 than loO ~or a water ri:lled mattre~a ) . :~t ~ these characterl~tics whlch impart to the waterbed mattress o~ the pre~ent 3 inV~ntton lt0 ~uperlor qualitîe3.
When the ~oam ~lab ie sub~tantially ~sturated wlth w~ter, lt~ precen~ wikhin th~ mattre~a i~ Ylrtu~lly undetectabla, Thi~ 18 b~cauce sl~b ~8 ic 30~t~ ~lexible, and when ~ubstan~lally ~aturatPd3 mo~tly water. MQreOVer9 35 ln the preferred embodiment~, the slab ~an be di~placed dow~lward~ through a ~ub~antial distance o~ otherwl~e unoccupied water. Thus the b~uyancy and physlcal char-acteri~tics oi the waterbed of the pre~ent invention are r~arly ldentical to that of a conventional waterbed .....

--6 ~
mattreB9 .
At the ~ame time that thepre~ent lnventlon retalns the deslrable qualitie~ o:e conventlonal waterbed mattrea~e~" lt virtually eïlmlr~te~ the u~ppe~li~
5 tendency of waterbed ma~tr~ee~ to be susccpt~ble to 5he creatlon Or w~v~ motion9 W~th th~ water ~atura'ced roam ~lab o~cupyln~; appr~x~rr~taly the t~p hal~ of th~ alat;t:Z~B~I, the water 1~ fr~e to move only ln khe bottom portlon o~
the mattre~ hu~, the amplitude of any l,~ave motlorl at 10 th~? top ~3urface o~ the mattre~s 1~ greatly reduc~d.
The operation o~ the ~ubstant~ally ~ater satur~
ated foam slab may be viewed ~n another way. Be¢~use the water "trapped" in the ~oam læ subætantlally re~tricted ~n movement and ~low, the ~bl~c08ity~ 0~ the water in 15 the upper half of the mattre~ can be viewed as being e~ectively increased many times over. While highly vi~cou~ water i~ known to dampen wave motion, lncreasing the vi~cosity o~ the li~uid fill o~ a waterbed mattre~
has been known to degrade such mattre~ bouyancy and 20 other physical propertie~. Moreover, ln BOme in~tances, increas$ng the viscoslty of the liquid fill may change the thermal conductlvity propertie~ of the liquid flll, .
thus prevent:~n~ proper heating of the mattre S9 . The pres~nt lnvention retain~ the positive qualitie~ o~
25 waterbeds becau~e the effective vlscosity of th0 water i~ only regionally modified9 wlth one half of the water k~lng unef~ected, 3.~ ~, As di~cus3ed be~ore, ~oam ~lab 18 i~ an open celled ~oam material readily capable o~ be~g ~1 lled wlth water ~or other liqul~ used to fil~ the mattre~), and at the ~ame time being partially suspended at the ~urrace o~ the liquld ~111. A preferred ~oam i~ polyurethane roam~ although rubber, vlnyl or ~eoprene ~oam 19 also ~atis~ackory. The speci~ic gravlty of the foam ~or a water ~llled mattre~ i9 1~B9 than 1, and pre~erably in tho range rrom .85 up to 1. Foam with di~e:rent speclric gravities, however, may be required ~or liquld 30 ~ahich are heavi~r or lightor than water,, Polyurethane foam i9 graded for 80~tne8E~ by the 35 ~oam manu~actur~ng industry on a ~cale ~own as the Indent -~oad Ierlectio~ ~oale (hereina~ter re~erred t~ a3 "XLD"). On this ~cale, 8 i~ the ~o~te~t, and numbers in the 100 's lndicate virtually rigid ~oam. Polyurethane ~oam i~ normaïly produced wlth an II~D number of a~out 45.

3.~

Polyurethane foam .~`or conventional mattresses has an I.LD number Or abou~ 30. The foam used ~n the pre~ent inventlon preferably has an ILD number in the range of 8 to 24, although sat-lsf'actory results can be achleved wlth f'oam havLng an ILD number rang-'Lng lnto the low 50's, The speclf'lc gravity of' the ~oam and 1tB ILD
number may be modif-led by ~Ln~ectlng some expandable poLy~
styre~e beads into the f'oam~
The f`oam material placed in the mattress need not be ln slab ~orm only~ For example, waterbed mat-tre~s 30, Lllust~ated in F-lgures 3 and 4, comprises a large number o~ dif~erent sized foam pieces 3~. These p'Leces can be placed loosely in the mattress, or as shown~
may be contained in a strong gauze-like or other sult-able enclosure 31. As ln the embodlment shown inFigures 1 and 2, it is pref'erred that the foanl occuples between 40 and 60 percent of' depth of` the expanded mattressO
Flgures 5 and 6 illustrate a slm~Llar embod~Lment~
Mattress 50 contains within it many tiny f'oam part-lcles 51 (typlcally less than about 0 25 inches ~n diameter).
As in the other embodiments, the f'oam partlcles pre.~erably occupy about 40 to 60 percent of the ~illed mattress.
Such partlcles may be "blown" ~nto the waterb~d mattreas 50 uslng convent:lona:L technLques for f':Llllng enclosures with foam partlcles. The f'oam partlcles 51 are shown as be~Lng unenclosed by a separate ;~nner el~velope or enclo~
sure. Because the partlcles are not conta:Lned by a separate lnner enclosure3 valve 16 ls ~itted with screen 3 52 to prevent any of the particles from escaping during khe ~illing or empty~ng of the mattress. If deslred the particle~ 51 can be contalned ln a sult2ble envelope or encloBure ~n t~le same manner shown ln Figures 3 and

4.
The mattresses shown in F-lgures 3 through 6 operate ln substantlally the sa~e manner as the waterbed mattress having the foam slab inslde of lt. However, the second two embodlments o~fer the economic advantage of using ~oam scraps whlch mlght otherw-lse be discarded ~ ~-9~
as waste material. Thus, these embodlments can be pro-duced at much lower costs.
The waterbed mattres~ of the pre~ent lnvent:Lon ls emptled and fllled ln the same rnanner as conventional waterbed mattresses. In f'-lll:Lng the mattress~ it ls pre~erred that the water be filled to about one lnch under the top o~ the mattres~. When emptylng the ma~tres~
of course) the water ~n the ~oam may have to be "rolled"
or wrung outO However, convenlent tap water ~ather than a vlscous fluld is normally used ln the present invention Moreover, the pre~ent inventlon, whlch can be ~olded or rolled up~ can be easily stored and shipped.
The pre~ent invention has been described in term~ of it~ preferred embodiments, ~owever, one skllled in the art can readily ascertain that the pre~ent inven-tlon can be easily modlfied to appear in substantially equivalent embodiment~. For example~ the pre~ent in-ventlon could be used for other ~lui~ fllled~ body suppor~
in~ furniture such as chalrs, sofas or couches.

SUPPLEMENTARY DISCLOSURE

-Means to adjust the speciEic gravity of the open celled foam of the subject waterbed is descri~ed together with other embodiments of the invention.
PRIOR A~T
United States Patent No. 4,192,031, issued to ~. Fogel, is illustrative of waterbeds comprising baffle chambers. In Fogel '031 a thin layer of preferably closed cell ~oam is used as a float or cork- to support the baffle chambers' top. The Fogel '031 baffle achieves wave reduction as a result of the top of the chamber wiping against the upper sheet o~ the waterbed. Such a waterbed is still subject to violent movement, though -for a shorter time than conventional waterbeds. Because the baffle's side panels are welded, or heat sealed, to the bottom sheet of the mattress, such mattress is more susceptible to leakage.
German Offenlegungsschrift 2,431,431, issued to Schmidt shows a waterbed mattress comprising ~luid impervious cells distributed throughout the mattress to displace liquid which would otherwise be required to fill the mattress, thus, reducing the total weight of the mattress.
United States Patent No. 3,S7~,873, issued to J. Weinstein, discloses a cushio for preventing the formation of decubitus ulcers. The cushion comprises a Elexi~le and elastic en~elope su~rounding and enclosing an internal matrix Eormed of open cell foam material. The internal matrix occupies the entire depth of the envelope. At suitable places the upper surface of the envelope is bonded t~ the top surfaces of the foam matrix. The envelope also encloses a fluid which passes through the open cells of the foam. This fluid is usually air, although water may be used in addition to air to help dissipate heat in the cushionO Weinstein teaches filling the 2/3 of the cushion's volume with water and to have the remaining 1/3 as air at atmospheric pressure. Weinstein also teaches filling the cushion completely with water.
However, since the matrix is relatively inelastic~ a sti~fer cushion results when it is filled completely with water. At no time is Weinstein concerned with the formation `~ SD10 of waves in his cushionsas the cushion does not contain enough water for waves to become a factor.
BRIEF DESCRIPTION OF DRAWINGS
_ .
Figure 7 is a cutaway, top view of another embodiment of the present invention;
Figure 8 is a side, sectional view of the present inven tion taken along line ~-8 of Figure 7;
Figure 9 is a side sectional view of the present invention showing a slab havi~g a low specific gravity material disposed throughout. ~ slab with such low specific gravity material disposed in it may be used in any of the embodiments shown in Figure 1-8;
Figure 10 is a side sectional view of another embodiment of the present invention; and Figure 11 is a side sectional view of a further embodiment of the present invention.
FURTHER DETAILED DESCRIPTION OF TEIE INVENTION
With reference to Figure 1 of the original Application and page 5, lines 2-3 thereof, the thickness of foam slab ~0 18 should be between about 20 and 80 percent of the depth of the filled mattress, and is preferably between ~0 and 60 percent of the depth of the filled mattress.
In the preferred embodiment, the specific gravity of the foam should be such that it remains substantially submerged in, yet partially suspended at the surface of, the liquid when the mattress is filled (i.e., 1.0 or less for a water filled mattress. If the specific gravity of the foam is greater than the specific gravity of the liquid fill (e.g., if the liquid fill is water and the specific gravity of the foam is greater than 1.0)~ ground cork, glass spheres, micro-balloons such as phenolic, expandable poly-styrene beads and other fillers having relatively low specific gravities (hereinafter sometimes referred to as -low specific gravity material ) may be disposed throughout the slab as shown in Figure 9 so that the slab has an overall specific gravity which is lower than the intended liquid fill of the waterbed mattress.

SDll .
.

6`~

It should also be noted that cellulosic sponge, which is open celled and has a specific gravity of less than 1.0, may be used to form the slab.
With reference to page 6 of the original Application where the fact that the present invention retains the desirable quallties of conventional waterbed mattresses is discussed, it has been found that the present invention also improves upon the desirable qualities. In this regard, wave motion is not only dampened, it is also converted to a slow, gentle rocking motion. The present invention provides support which is actually more comfortable than that provided by a waterbed mattress containing only liquid fill. Users of the waterbed mattress of the present invention feel more secure on such mattress. This added factor of comfort was a totally unex-pected advantage.
To achieve the desired specific gravity discussed at page 7, lines 20 - 30 and page 8, lines 6 - 8 of the original Application, low speciEic gravity material such as expandable polystryrene beads, ground cork, micro-balloons and the like 2~ may be disposed throughout the foam as discussed before and as shown in Figure 9 twherein slab 98 having low specific gravity material95~ disposed in it is illustrated~.
Figures 7 and 8 illustrate another embodiment of the invention. In this embodiment waterbecl mattress 70 comprises a foam slab 72 which is of e~g crate design. This foam slab is made o the same material as foam slab 18 and foam particles 32 and 51 o Figures 2, 4 and 6, respectively.
That is, the foam is an open celled foam which may be poly-urethane or rubber, vinyl or neoprene. The foam slab may also have low specific gravity material such as ground cork, micro-balloons and the like disposed throughout so that its overall specific gravity is less than the liquid fill.
Also, the slab may he formed of cellulosic sponge instead of foam.
The embodiment comprising the egg crate design is preferred over the embodiment comprising slab 18, which is of rectangular cross section. This is because teats 7 3~

e~tending upwards from the main body of slab 72 provide at the upper surface of the mattress a space in which some of the liquid fill is virtual.ly trapped, yet at the same time can flow more freely within the space than liquid fill similarly situated in the embodiments illustrated in Figures 1-6. Thus, the feel of a conventional waterbed is even more closely reproduced while the secure feeling previously discussed is still maintained. Also, the improved support provided by the invention is present. In fact, to the extent that the upward extending teats soften the initial contact with the waterbed, the comfort qualities of the invention are even further improved.
Another beneficial feature of the embodiment shown in Figures 7 and 8 is that less material need be used to form slab 72 than is needed to form slab 18. For example, if ~eats 74 comprise about 50% of slab 74, two slabs 74, each having a total thickness of 4 inches, may be formed from a piece of Eoam material having a rectangular cross section of 6 inches in thickness. To form two slabs 18, each having a total thickness of 4 inches, a piece of 8 inch foam must be used.
Thus, a savings of 25% in material is achieved. As the size of the teats increases in proportion of the total thickness of the slab, additional savings in material may be achieved.
A further advantage of the embodiment shown in Figures 7 and 8 ts that the slab may be made of a more rigid materlal.
For example, if polyurethane Eoam is used, the normally produced foam having an II,D of about ~5 may be used.
Eigures 10 and 11 show two other embodiments, 90 and 92 respectively, of the present inventionA In Figure 10 the waterbed mattress comprises a substantially open celled foam slab 91 which has an overall specific gravity which is greater than that of the liquid fill. Slab 91, as can be seen, has a rectangular cross section. It has been found that significant wave reduction can be achieved with this embodiment. The slab should be at least 40-50~ as thick as the depth of the mattress, and preferably is about 70% as deep.
The waterbed mattress of Figure 11 comprises slab 93 which is of e~g crate design. This slab also has a specific 3~

gravity greater than that of the liquid fill. In this embodiment the total thickness of this slab should be about the same as that of slab 91. The teats 94 may comprise up to about 80% of the to~al thickness of the slab.
The waterbed mattress of the present invention is emptied and filled in the same manner as conventional waterbed mattresses. In filling the mattress of the embodiments shown in Figures 1-9, it is preferred that the liquid fill be filled to about one inch under the top of the mattress. The addition or reduction of water allows a degree of wave action adjustability. The mattress of the embodiments shown in Figures 10 and 11 should be filled to the top. The embodiments shown in E'igures 7-9 and in Figure 11 would still function if slabs 72, 98 and 93 were positioned with teats 74, 99 and 94, respectively, extending downward.

. .

Claims (57)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A body supporting container capable of being filled with a liquid, said container having a substantially open celled foam disposed therein, said foam extending substantially along the horizontal dimensions of said container when said container is filled, said foam having a material of low specific gravity disposed throughout its body, said material of low specific gravity causing the foam to float in the liquid, above the bottom wall of the container, close to the top wall of the container, whereby wave motion in said filled container is dampened while the desirable qualities of the liquid filled body supporting container are retained.

2. The container of Claim 1 wherein the thickness of said substantially open celled foam is 40 to 60 percent of the depth of said container when it is filled.

3. The container of Claim 1 wherein said open celled foam has a specific gravity less than that of said liquid.

4. The container of Claim 1 wherein said low specific gravity material is comprised of expandable polystyrene beads.

5. The container of Claim 1 wherein said liquid is water and said substantially open celled foam has a specific gravity in the range of about 0.85 to 1.

6. The container of Claim 1 wherein said substan-tially open celled foam is chiefly open celled vinyl foam.

7. The container of Claim 1 wherein said substan-tially open ceiled foam is chiefly open celled polyurethane foam.

8. The container of Claim 7 wherein said substantially open celled foam has an ILD number between about 8 and about 24.

9. The container of Claim 1 wherein said substantially open celled foam is chiefly open celled foam rubber.

10. The container of claim 1 wherein said substantially open celled foam is chiefly open celled neoprene foam.

11. The container of Claim 1 wherein said substantially open celled foam is a single foam slab.

12. The container of Claim 1 wherein said substantially open celled foam disposed in said container is a plurality of foam particles.

13. The container of Claim 12 wherein said plurality of foam particles is held in an inner enclosure.

14. The container of Claim 1 wherein said substantially open celled foam disposed in said container is a plurality of foam pieces.

15. The container of Claim 14 wherein said plurality of foam pieces is held in a gauze-like inner enclosure.

16. The container of Claim 1 wherein said foam is in contact with the top wall of said container.

17. A waterbed mattress having disposed inside it water and a substantially open celled foam having an ILD
number less than 55, said substantially open celled foam having a specific gravity such that it is substantially submerged in said water, said substantially open celled foam substantially corresponding to the horizontal dimensions of said mattress and occupying 20 to 80 percent of the depth of said mattress, whereby said substantially open celled foam effectively increases the viscosity of the water in the region of said mattress in which it is present while leaving the viscosity of the water in the remaining regions of the mattress unchanged, thereby dampening wave motion in said mattress and retaining the bouyant and physical characteristics of a conventional waterbed mattress.

18. The mattress of Claim 17 wherein said substantially open celled foam occupies 40 to 60 percent of the depth of said mattress when it is filled.

19. The mattress of Claim 18 wherein said substantially open celled foam has a specific gravity between about .85 and 1.

20. The-mattress of Claim 18 wherein said substantially open celled foam has low specific gravity material disposed in it so that the specific gravity of said substantially open celled foam is less than 1.

21. The mattress of Claim 20 wherein said substantially open celled foam is chiefly open celled vinyl foam.

22. The mattress of Claim 20 wherein said substantially open celled foam is chiefly open celled polyurethane foam.

23. The mattress of Claim 22 wherein said substan-tially open celled foam has an ILD number between about 8 and 24.

24. The mattress of Claim 20 wherein said substantially open celled foam is chiefly open celled neoprene foam.

25. The mattress of Claim 20 wherein said substantially open celled foam is open celled foam rubber.

26. The mattress of Claim 17 wherein said substantially open celled foam is in the form of a slab having a substantially rectangular cross section.

27. A waterbed mattress capable of being filled with a liquid, said mattress having a flexible substantially open celled foam having an ILD number less than 55 disposed therein, said foam extending substantially along the horizontal dimensions of said mattress and occupying 20 to 80 percent of the depth of said mattress when said mattress is filled, said open celled foam capable of being substantially submerged in, yet partially suspended at the surface of, said liquid when said mattress is filled, whereby said open celled material effectively increases the viscosity of the water in the upper region of said mattress while leaving the viscosity of the water in the lower region of the mattress unchanged, thereby dampening wave motion in said mattress and retaining the bouyant and physical characteristics of a conventional waterbed mattress.

28. A body supporting container capable of being filled with a liquid, said container having a substantially open celled foam disposed therein, said foam extending substantially along the horizontal dimensions of said container and occupying 20 to 80 percent of the depth of the container when said container is filled, said foam having an ILD number less than 90, wherein said foam effectively increases the viscosity of the water in the upper region of said mattress while leaving the viscosity of the water in the lower region of the mattress unchanged, thereby dampening wave motion in said mattress and retaining the bouyant and physical characteristics of a conventional liquid-filled body supporting container.

CLAIMS SUPPORTED BY THE SUPPLEMENTAL DISCLOSURE

29. The container of Claim 1 wherein said open celled foam has a specific gravity equal to that of said liquid.

30. The container of Claim 1 wherein said open celled foam has a specific gravity greater than that of said liquid.

31. The container of Claim 1 wherein said low specific gravity material is ground cork.

32. The container of Claim 1 wherein said low specific gravity material is comprised of glass beads.

33. The container of Claim 1 wherein said low specific gravity material is comprised of phenolic beads.

34. The container of Claim 1 wherein said substantially open celled foam is a single foam slab comprising a base with projections extending upward therefrom.

35. The container of Claim 1 wherein said foam is a single foam slab of egg crate design.

36. The container of Claim 35 wherein the teaks of said slab of egg crate design extend upwards from said slab.

37. The container of Claim 36 wherein the teats comprise about 50% of the thickness of said slab.

38. The mattress of Claim 17 wherein said substantially open celled foam is in the form of a slab having an egg crate design.

39. The mattress of Claim 38 wherein the teats of said slab having an egg crate design extend upwards from said slab.

40. The mattress of Claim 39 wherein said slab has a specific gravity which is no greater than 1Ø

41. The mattress of Claim 39 wherein said slab has low specific gravity material disposed in it so that the specific gravity of the foam is no greater than 1Ø

42. The mattress of Claim 39 wherein said substantially open celled foam is chiefly open celled polyurethane foam.

43. The mattress of Claim 39 wherein said substantially open celled foam has a specific gravity of greater than 1Ø

44. The mattress of Claim 43 wherein the thickness of said slab is between 40 and 80 percent of the depth of said mattress when it is filled.

45. The mattress of Claim 26 wherein said slab has projections extending upwards therefrom, the ends of said projections having dimensions no bigger across than the distance between said projections.

46. The mattress of Claim 27 wherein said foam is cellulosic sponge.

47. A waterbed mattress having dampened wave motion characteristics, said mattress comprising a watertight container and a slab of substantially open celled foam having an ILD number less than 90, said foam extending substantially along the horizontal dimensions of said mattress and occupying 20 to 80 percent of the depth of the mattress when the mattress is filled, said slab comprising a base with projections extending vertically therefrom, the ends of said projections having horizontal dimensions which are no greater than the smallest distance between projections, said projections comprising at least 50 percent of the vertical height of the slab.

48. The waterbed mattress of Claim 47 wherein said projections extend upwards.

49. The waterbed mattress of Claim 48, said slab of open celled foam having an egg crate design, the teats of said egg crate design being said projections.

50. The waterbed mattress of Claim 48 wherein said open celled foam has a specific gravity greater than that of the liquid fill of said mattress, the height of said slab being at least 40 percent of the depth of the mattress.

51. The waterbed mattress of Claim 47 wherein said projections extend downwards.

52. A body supporting container capable of being filled with a liquid, said container having a plurality of substantially open celled foam pieces disposed therein, said foam extending substantially along the horizontal dimensions of said container and occupying 20 to 80 percent of the depth of the container when said container is filled, said foam having an ILD number less than 50 and having low specific gravity material disposed therein so that the specific gravity of said substantially open celled foam is less than the specific gravity of said liquid, said plurality of foam pieces being held in an inner enclosure, said inner enclosure comprising a gauze like material completely enclosing said plurality of foam pieces while permitting liquid transfer into and out of the inner enclosure, whereby wave motion in said filled container is dampened.

53. A waterbed mattress having dampened wave motion characteristics, said mattress comprising a water-tight container and a slab of substantially open celled foam having a material of low specific gravity disposed through-out its body, said material of low specific gravity causing the foam slab to float in the water, above the bottom wall of the mattress, close to the top wall of the mattress, said slab comprising a base with tapered projections extending vertically therefrom, said projections comprising at least 50 percent of the vertical height of the slab, said slab extending substantially along the horizontal dimensions of the container and occupying 20 to 80 percent of the depth of the container.

54. The waterbed mattress of Claim 53 wherein said projections extend upwards.

55. The waterbed mattress of Claim 54, said slab of open celled foam having an egg crate design, the teats of said egg crate design being said projections.

56. The waterbed mattress of Claim 53 wherein said projections extend downwards.

57. A body supporting container capable of being filled with a liquid, said container having a plurality of substantially open celled foam pieces disposed therein, said foam extending substantially along the horizontal dimensions of said container, said foam having low specific gravity material disposed therein so that the specific gravity of said substantially open celled foam is less than the specific gravity of said liquid, said plurality of roam pieces being held in an inner enclosure comprising a gauze-like material completely enclosing said plurality of foam pieces while permitting liquid transfer into and out of the inner enclosure, whereby wave motion in said filled container is dampened.