GB2056270A

GB2056270A - Waveless waterbed

Info

Publication number: GB2056270A
Application number: GB7942166A
Authority: GB
Original assignee: United Foam Corp
Current assignee: United Foam Corp
Priority date: 1979-07-23
Filing date: 1979-12-06
Publication date: 1981-03-18
Also published as: FR2461474A1; JPS5620413A; AU5409079A; DE2951779A1; CA1182932A; NL7909133A; IT7928389A0; BE880906A; IT1126700B

Abstract

The present invention provides a waterbed mattress 10 having a slab 18 of open celled foam e.g. polyurethane substantially submerged in, yet partially suspended above the upper surface of, the liquid fill of the mattress. The waterbed mattress retains the positive qualities of buoyant support and comfort of conventional waterbed mattresses, and reduces the undesired wave motion often created within the mattress. Other embodiments 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 invention may be incorporated in waterbeds or other body supporting furniture such as chairs and couches in which a liquid fill medium is used. <IMAGE>

Description

SPECIFICATION Waveless waterbed TECHNICAL FIELD This invention relates to waterbed mattresses.

BACKGROUND OF THE PRIOR ART Since the late 1960's, when waterbeds were first introduced, waterbeds have been gaining increasing acceptance. It has been recognized that waterbeds provide dimensions of comfort and bodily support not available from conventional inner spring or foam mattress bedding systems.

Waterbeds have also become favored for their therapeutic and other user qualities.

However, waterbeds have been beset with a major disadvantage. This disadvantage is the tendency for wave motion to be created in the waterbed mattress. Wave motion in the mattress can make users of the waterbed uncomfortable, and consumer fear of "seasickness" has inhibited the acceptance of waterbeds.

Heretofore, attempts have been made to provide a waterbed mattress that would retard or dampen wave motion. The June, 1979 issue of California Business, in an article by Bob Gilbert entitled "Taking the Plunge" (p. 54), reports at page 60 that it was hoped "hybrid" beds would solve this wave motion problem. A hybrid bed comprises a water mattress with a foam topping placed over the mattress. Unfortunately, hybrid beds are as susceptible to wave motion as conventional waterbeds.

The same article reports, also at page 60, that attempts to achieve motionless characteristics include putting plastic baffles inside the waterbed mattress, and "floating a jell on the top half of a mattress, separated from water on the bottom half by a vinyl sheet." Another recent attempt to reduce wave motion includes construction of baffle chambers within the mattress. The chambers' side panels are welded to the mattress' bottom sheet. The chambers' tops, connected to the upper edges of the side panels, are made of foam and allowed to float free of any contact with the mattress in an effort to form an internal breakwater.

The above discussed attempts to reduce wave motion have met with various degrees of success.

Unfortunately, whatever degree of wave dampening achieved by such systems has often been more than offset by increased costs and complexities of manufacture. Moreover, such systems are often expensive to ship, and they pose difficulties to consumers who wish to empty, reposition, and refill their waterbeds. In this regard, waterbed systems requiring special gels or additives cause additional problems and expenses.

United States Patent Nos. 3,702,484 and 3,736,604 issued to R. Carson, Jr., and to S.

Tobonick and A. Saminoff, respectively, disclose hybrid type waterbeds. Waterbed mattresses comprising baffles to dampen wave motion are disclosed in C. Mollura's United States Patent No.

4,141,770 and I. Fogel's United States Patent No.

4,152,796. United States Patent No. 3,349,953, .issued to R. Conaway and J. Spindler discloses a tank with a baffle system inserted to prevent sloshing of liquid in the tank.

United States Patent No. 3,748,669, issued to F. Warner, discloses a waterbed mattress comprising fluid 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. 3,787,908, issued to W.

Beck and N. Sweeny, also discloses a liquid filled -mattress having low density cellular particles suspended throughout the liquid in order to reduce the weight of the filled particles. The cellular particles also improve the insulative properties of the liquid fill. Beck et al also teach adding a viscosity modifier to the liquid fill to improve the waterbed mattresses' dimensional stability characteristics.

United States Patent No. 3,585,356, issued to C. Hall, discloses producing a dampening effect by placing a suitable solid material in suspension in the fluid within the mattress. Hall teaches that ground or shredded styrofoam at a volume ratio of about one to three to water produces a dampening effect. Hall also teaches replacing the styrofoam by starch or other material which will stray in suspension in the fluid. An alternative embodiment is also shown by Hall, wherein small blocks of a material such as styrofoam float upon the entire surface of the fluid. Hall teaches that the blocks rub against each other and their reaction with the fluid provides independent support for all parts of a body positioned on the waterbed mattress.

D. McGrew, in United States Patent No.

3,810,265, teaches dampening wave motion by adding a water soluble viscosity increasing agent to the liquid fill of the mattress. McGrew also discusses the preference that the water mattress not be secured to the frame, especially along the upper marginal surface of the mattress to insure preservation of even bouyancy and prevention of a shear-producing ham mocking effect. For this purpose the upper surface of the mattress may carry some slack as provided by a plurality of pleats in the upper mattress surface. Additionally, a foam rubber or other elastic pad may be floatably positioned on the upper mattress surface for added comfort or temperature compensation.

The systems described by the above discussed patents have not achieved a satisfactory wave dampening effect without compromising the qualities expected of conventional waterbeds.

Moreover, such systems bear the disadvantages discussed earlier; namely, increased costs and complexities of manufacture, increased costs of shipping, increased difficulties in emptying and refilling, and increased maintenance costs.

BRIEF SUMMARY OF THE INVENTION The present invention is 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 invention may be incorporated in waterbeds or other body supporting furniture such as chairs and couches in which a liquid fill medium is used.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cutaway, top view of an embodiment of the present invention.

Figure 2 is a side sectional view of the present invention taken along line 2-2 of Figure 1.

Figure 3 is a cutaway, top view of another embodiment of the present invention.

Figure 4 is a side, sectional view of the present invention taken along line 4 4 of Figure 3.

Figure 5 is a cutaway, top view of still another embodiment of the present invention.

Figure 6 is a side, sectional view of the present invention taken along line 6-6 of Figure 5.

DETAILED DESCRIPTION OF THE INVENTION In the following discussion, the same numeral will designate like elements throughout the drawings. For example, in Figures 1 through 6, which illustrate preferred embodiments of this invention, the upper and lower sheets of the waterbed mattress are designated, respectively, by numbers 11 and 12 throughout. While this description often refers to "water" as the liquid fill for the invented waterbed mattress, it should be understood that the present invention contemplates other liquids such as aqueous compositions containing germicides, fungicides, viscosity modifiers and/or additives for enhanced heat transfer.

The present invention incorporates many of the elements of conventional waterbed technology.

Sheets 11 and 12 are typically vinyl sheets joined together by a heat seal 14 to form a fluid retaining compartment. The mattress has a standard valve 1 6 to allow for the filling and emptying of the mattress.

Referring to Figures 1 and 2, the diacritic feature of the present invention can be seen.

Waterbed mattress or bladder 10 comprises an open celled foam slab 1 8. This slab is disposed between sheets 11 and 12 before they are sealed together. The foam slab is dimensioned so that it substantially occupies the length and width of the waterbed mattress. The thickness of foam slab 18 is preferably between 40 to 60 percent of the depth of the filled mattress. For example, if the filled mattress is six (6) inches deep, foam slab 18 should preferably be about 2.4 to 3.6 inches thick to obtain optimum results. Satisfactory results can also be obtained when the thickness of foam slab 1 8 is 20 to 100 percent of the depth of the filled mattress. In this regard, individual tastes may be accommodated by having available waterbed mattresses with different thicknesses of foam sealed within them. The cells of the foam are interconnected.Thus, water flows into and fills all the cells of that portion of the foam which is submerged.

Foam slab 18, besides being capable of being filled with water, is a soft resilient material, capable of flexing under body weight. The specific gravity of the foam is such that it remains substantially submerged in, yet partially suspended at the surface of, the liquid when the mattress is filled (i.e., less than 1.0 for a water filled mattress). It is these characteristics which impart to the waterbed mattress of the present invention its superior qualities.

When the foam slab is substantially saturated with water, its presence within the mattress is virtually undetectable. This is because slab 1 8 is soft, flexible, and when substantially saturated, mostly water. Moreover, in the preferred embodiments, the slab can be displaced downwards through a substantial distance of otherwise unoccupied water. Thus the bouyancy and physical characteristics of the waterbed of the present invention are nearly identical to that of a conventional waterbed mattress.

At the same time that the present invention retains the desirable qualities of conventional waterbed mattresses, it virtually eliminates the unappealing tendency of waterbed mattresses to be susceptible to the creation of wave motion.

With the water saturated foam slab occupying approximately the top half of the mattress, the water is free to move only in the bottom portion of the mattress. Thus, the amplitude of any wave motion at the top surface of the mattress is greatly reduced.

The operation of the substantially water saturated foam slab may be viewed in another way. Because the water "trapped" in the foam is substantially restricted in movement and flow, the "viscosity" of the water in the upper half of the mattress can be viewed as being effectively increased many times over. While highly viscous water is known to dampen wave motion, increasing the viscosity of the liquid fill of a waterbed mattress has been known to degrade such mattress's bouyancy and other physical properties. Moreover, in some instances, increasing the viscosity of the liquid fill may change the thermal conductivity properties of the liquid fill, thus preventing proper heating of the mattress. The present invention retains the positive qualities of waterbeds because the effective viscosity of the water is only regionally modified, with one half of the water being uneffected.

The thermal character of the waterbed mattress of the present invention is superior to that of conventional waterbed mattresses. Condensation forms on the outer surface of conventional waterbed mattresses due to the difference in temperature between the cool water within the mattress and the relatively warm air outside the mattress. This problem is increased when warm bodies are disposed on the upper surface of the mattress. Condensation does not form on the present invention, however, due to the "wet suit" effect. This effect derives its name from the phenomenum experienced by under-water divers wearing certain rubber diving suits. Despite the fact that water leaks into such suit, divers still remain warm even though they are swimming in very cold waters.This is caused by the fact that the water which leaks into the suit is virtually trapped between the diver's body and his suit. This trapped water quickly rises to the body temperature of the diver and thereafter forms a thermal barrier between the diver and the surrounding cold water. In the same manner, the water "trapped" in the foam near the surface of the mattress of the present invention is heated to the temperature of the air, or of a body, on the other side of the mattress surface. Because movement and flow of the water is inhibited by the foam, convection currents, the principal means by which heat transfer is accomplished in water, are not formed. Thus, a thermal barrier is formed between the surface of the mattress and the cooler water deeply within the mattress.

Condensation, therefore, is eliminated because little or no temperature difference exists at either side of the mattress surface.

As discussed before, foam slab 1 8 is an open celled foam material readily capable of being filled with water (or other liquid used to fill the mattress), and at the same time being partially suspended at the surface of the liquid fill. A preferred foam is polyurethan foam, although rubber, vinyl or neoprene foam is also satisfactory.

The specific gravity of the foam for a water filled mattress is less than 1, and preferably in the range from .85 up to 1. Foam with different specific gravities, however, may be required for liquid fills which are heavier or lighter than water. Of course, the specific gravity of the foam is inconsequential when it occupies 100 percent of the depth of the filled waterbed mattress.

Polyurethane foam is graded for softness by the foam manufacturing industry on a scale known as the Indent Load Deflection scale (hereinafter referred to as "ILD"). On this scale, 8 is the softest, and numbers in the 100's indicate virtually rigid foam. Polyurethane foam is normally produced with an ILD number of about 45. Polyurethane foam for conventional mattresses has an ILD number of about 30. The foam used in the present invention preferably has an ILD number in the range of 8 to 24, although satisfactory results can be achieved with foam having an ILD number ranging into the low 50's.

The specific gravity of the foam and its ILD number may be modified by injecting some expandable polystyrene beads into the foam.

The foam material placed in the mattress need not be in slab form only. For example, waterbed mattress 30, illustrated in Figures 3 and 4, comprises a large number of different sized foam pieces 32. These pieces can be placed loosely in the mattress, or as shown, may be contained in a strong gauze-like or other suitable enclosure 31.

As in the embodiment shown in Figures 1 and 2, it is preferred that the foam occupies between 40 and 60 percent of depth of the expanded mattress.

Figures 5 and 6 illustrate a similar embodiment.

Mattress 50 contains within it many tiny foam particles 51 (typically less than about 0.25 inches in diameter). As in the other embodiments, the foam particles preferably occupy about 40 to 60 percent of the filled mattress. Such particles may be "blown" into the waterbed mattress 50 using conventional techniques for filling enclosures with foam particles. The foam particles 51 are shown as being unenclosed by a separate inner envelope or enclosure. Because the particles are not contained by a separate inner enclosure, valve 1 6 is fitted with screen 52 to prevent any of the particles from escaping during the filling or emptying of the mattress. If desired the particles 51 can be contained in a suitable envelope or enclosure in the same manner shown in Figures 3 and 4.

The mattresses shown in Figures 3 through 6 operate in substantially the same manner as the waterbed mattress having the foam slab inside of it. However, the second two embodiments offer the economic advantage of using foam scraps which might otherwise be discarded as waste material. Thus, these embodiments can be produced at much lower costs.

The waterbed mattress of the present invention is emptied and filled in the same manner as conventional waterbed mattresses. In filling the mattress, it is preferred that the water be filled to about one inch under the top of the mattress.

When emptying the mattress of course, the water in the foam may have to be "rolled" or wrung out.

However, convenient tap water rather than a viscous fluid is normally used in the present invention. Moreover, the present invention, which can be folded or rolled up, can be easily stored and shipped.

The present invention has been described in terms of its preferred embodiments. However, one skilled in the art can readily ascertain that the present invention can be easily modified to appear in substantially equivalent embodiments. For example, the present invention could be used for other fluid filled, body supporting furniture such as chairs, sofas or couches.

Claims

1. A body supporting container capable of being filled with a liquid, said container having an open celled foam disposed therein, said foam extending substantially along the horizontal dimensions of said container and capable of being substantially submerged in, yet partially suspended at the surface of, said liquid when said container is filled, whereby wave motion in said filled container is dampened.

2. The container as claimed in Claim 1, wherein the thickness of said foam is 20 to 100 percent of the depth of said container when it is filled.

3. The container as claimed in Claim 1 , wherein the thickness of said foam is 40 to 60 percent of the depth of said container when it is filled.

4. The container as claimed in Claim 1, wherein said liquid is water and said foam has a specific gravity in the range of about .85 up to 1.

5. The container as claimed in Claim 1, wherein said foam is open celled vinyl foam.

6. The container as claimed in Claim 1, wherein said foam is open celled polyurethane foam.

7. The container as claimed in Claim 1, wherein said foam is open celled polyurethane foam with ILD number less than 55.

8. The container as claimed in Claim 7, wherein said foam has an ILD number between about 8 and about 24.

9. The container as claimed in Claim 1, wherein said foam is open celled foam rubber.

10. The container as claimed in Claim 1, wherein said foam is open celled neoprene foam.

11. The container as claimed in Claim 1, wherein said foam is a single foam slab.

12. The container as claimed in Claim 1, wherein said foam comprises a plurality of foam pieces or particles.

13. The container as claimed in Claim 12, wherein said plurality of foam pieces, or particles, is held in an inner enclosure.

14. The container as claimed in Claim 1, wherein the thickness of said foam is about 100 percent of the depth of said container when it is filled.

1 5. The container as claimed in Claim 1, wherein said filled container with said open celled foam therein defines a waterbed mattress.

16. The container as claimed in claim 15, wherein said foam is soft and flexible, whereby such 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 buoyant and physical characteristics of a conventional waterbed mattress.

17. A body supporting container capable of being filled with a liquid, constructed substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.