Waterbed mattress

An improved adjustable waterbed mattress with hydrostatic wave absorption comprising a water-inflatable bag-like enclosure containing therein a non-woven or very loosely woven expanded fiber product, unbonded or fixed with a binder to the same or another fiber product, which resists decomposition in water. When a user sits or lies on a conventional waterbed there is a tendency to sink or bottom out especially on the edge and an undesirable wave front is created in the waterbed mattress. The provision of the subject expanded fiber product in the waterbed mattress of the present invention substantially mitigates and dissipates this wave front and allows the bed to be easily packaged, filled, heated, drained and stored.

BACKGROUND OF THE INVENTION 
This invention relates to waterbeds and, more specifically, to an improved 
motion-control waterbed mattress. Waterbeds are ordinarily comprised of a 
rigid frame constructed of suitable plastic or wood supporting a bag-like 
enclosure which is filled with water through a water-filling means. The 
frame serves to confine the water-inflatable bag-like enclosure which is 
ordinarily constructed of vinyl or other suitable watertight flexible 
sheets. 
The waves, the bottoming out and the edge collapsing created by the user's 
sitting, lying or moving on the waterbed mattress cause discomfort for the 
user or users thereby discouraging waterbed use. In the past, attempts 
have been made to suppress this discomfort problem with varying degrees of 
success. For example, baffles, tie-downs, and floats with tie-downs and/or 
baffles tied to the underside of the top and/or upper side of the bottom 
of the bag-like enclosure of the waterbed mattress have been employed to 
suppress motion. However, these conventional motion suppression means 
require additional watertight seams at high stress points which eventually 
fail ultimately resulting in water leakage. 
Gelling agents have also been used in the past to suppress undesirable wave 
motion. But gell presents blending, heating and removal problems, its 
viscosity varies with the mineral content of differing water supplies 
employed and, upon its removal, more gelling agent is required to refill 
the mattress at considerable cost to the consumer. 
Plastic foam inserts in the waterbed mattress constitute another approach 
to the control of undesirable wave motion and bottoming out. But plastic 
foam is excessively bulky, is difficult to package, handle and ship when 
disposed within the waterbed mattress, and when appreciably depressed to 
reduce bulk, it subsequently recovers an undesirably low percentage of its 
original dimension. Moreover, when the mattress containing foam inserts 
are water filled, the foam retains air which is extremely difficult to 
remove from the mattress. Additionally, the foam interferes with heat 
transfer in the water and acts as a sponge inhibiting water drainage. 
SUMMARY OF THE INVENTION 
It is a major object of the present invention to inhibit and control 
undesirable wave movement and to eliminate the tendency to excessively 
sink or bottom out, especially on the edge, of waterbed mattresses 
provided with at least one water-filling means. As hereinafter explained, 
this object is attained by dissipating the energy of the wave front. 
Another object of the present invention is to control waves and bottoming 
out and to provide edge support in waterbed mattresses through an 
uncomplicated structure without the employment of gell additives or 
cumbersome plastic foam inserts. 
The safety benefits and advantages of the present invention are 
particularly important. Conventional waterbeds that are intended to 
inhibit undesirable wave movement are typically provided with baffles, 
coil tie-downs, plastic foam inserts, gelling agents or like materials or 
systems to inhibit wave movement. Structures including but not restricted 
to coil tie-downs and baffles are butt seamed to the surfaces of the outer 
bag-like enclosure. As the force of the wave strikes these baffles, 
separators or tie-downs, they resist the wave front and tug against the 
surfaces to which they are attached by butt seams thereby causing leaks at 
these seams. These systems must typically inhibit in excess of 1,000 
pounds of water from shifting. The resulting stress commonly causes butt 
seam tear-outs which cannot be patched. These leakage and tear-out 
problems are eliminated in the present invention wherein a fibrous 
material is disposed within the waterbed mattress. Instead of the 
unyielding resistence to the wave front which characterizes baffles, 
separators, tie-downs and like systems, the fibrous material of the 
present invention breaks up and dissipates the wave front without 
undesirable tension by providing a mesh or lattice-like structure. The 
unyielding tension which typically causes leaks at the butt seams in 
waterbed mattresses provided with baffles, separators or tie-downs is 
thereby avoided. 
As compared to plastic foam inserts which are difficult to store, heat and 
drain, the fiber media of the present invention allows the bed to be 
simply and easily packaged, shipped, water filled, adjusted, air bled, 
heated, drained and stored. 
Additionally, variations of perimeter edge support, bottoming out and bed 
center support can be controlled by the shaping and positioning of the 
inner fiber fill and by selection of differing types of inner fiber fill; 
i.e., more fill proximate to the perimeter of the waterbed provided 
greater edge support and reduces bottoming out at the parimeter. 
Broadly consisered, the improved waterbed mattress of the present invention 
is disposed in and supported by a rigid frame and is comprised of a 
water-inflatable bag-like enclosure containing a fibrous material which 
resists decomposition in water. Typically the water-inflatable bag-like 
enclosure is constructed of suitable watertight panels. In ordinary 
construction this bag-like enclosure is provided with a top panel, a 
spaced-apart bottom panel and one or more edge panels interconnecting the 
top and bottom panels. However, the invention also encompasses a bag-like 
enclosure which is constructed with or without separate top, bottom and 
side panels or constructed with any combination of said panels. The 
enclosure is also provided with one or more water-filling and valve means. 
The fibrous material contained within the water-inflatable bag must resist 
decomposition in water, and must be a non-woven or very loosely woven 
expanded fiber product, unbonded or fixed with a binder in structure. 
In operation the bag-like enclosure provided with the net-like, thread-like 
or shredded fibrous structure is filled with water and the water volume 
adjusted to satisfy the user's preference. 
When the user sits, lies or moves on the waterbed mattress the fibrous 
material or structure breaks up and dissipates the wave front created in 
the bag-like enclosure because it forms a mesh or lattice-like obstruction 
to the movement of the water. 
Other objects, advantages, benefits and features of the subject improved 
waterbed mattress with hydrostatic wave absorption not heretofore set 
forth will be more fully understood from the following detailed 
description.

DETAILED DESCRIPTION 
In accordance with the present invention the fibrous material or structure 
spreads out into the contained water volume. The fibrous material 
contemplated by the present invention is a non-woven or very loosely woven 
expanded fiber product or combination of products, each of which is 
unbonded or fixed with a binder. Examples include, but are not restricted 
to polyester fibers which are either unbonded or bonded with acrylic 
resin, either unwoven or very loosely woven. The invention is not 
restricted to the use of such bonded or unbonded polyester or other 
man-made fibers. Other suitable fibers, fabric or plastic may be used 
which resists decomposition in water. Additionally, the material or 
combination of materials should be highly compressible, i.e., they should 
compress to at least approximately one-tenth or less of their original 
dimension and be capable of regaining substantially their entire original 
size when immersed in water. Thus a typical soft-cell material such as 
foam or the material known as rubberized horsehair would not prove 
satisfactory for the purposes of the present invention. The materials 
contemplated by the present invention should preferably be fibrous, 
net-like, thread-like or shredded so that air can pass easily through each 
material's gridwork. This characteristic is particularly important because 
entrapped air within the waterbed mattress can cause other materials such 
as conventional foam inserts to float toward the water surface within the 
waterbed mattress. Materials having a density of about 0.5 to 0.2 pounds 
per cubic foot, such as bonded or unbonded polyester or other expanded 
fibers, are appropriate for the purposes of the present invention. 
Similarly appropriate are fiberglass fibers. 
A loose unbonded fiber, such as batting commonly used in pillows, is within 
the scope of the present invention but is not a preferred embodiment. When 
such materials are used, the water-filling and water-draining means of the 
waterbed mattress must be provided with a screen to prevent clogging. Use 
has shown that loose unbonded fibers are less effective than bonded fibers 
in bringing about wave reduction. Each of the unbonded fibers has the 
capability of moving independently within the waterbed mattress causing 
serious draining problems. Unbonded fibers are also more cumbersome to use 
in the manufacturing process and in packaging. Additionally, a greater 
quantity of unbonded fibers must be employed than is necessary with bonded 
material. The unbonded fibers of the present invention include loose 
polyester fiber, garnetted polyester fiber and garnetted polyester fiber 
attached to a skrim. 
The inclusion of the material described herein attenuates wave action 
without appreciably attenuating heat transfer within the waterbed 
mattress. 
In one example the waterbed mattress, 84" long by 72" wide by 9" deep, was 
provided with three units of non-woven expanded fiberglass material fixed 
with a phenolic binder. The material was resistant to water decomposition 
and each unit was 64" long by 64" wide by 2" deep. The units were 
connected to form a single unit. 
In another example, a waterbed mattress 84" long, 72" wide and 9" deep was 
provided with a polyester bonded media. The material was a non-woven 
expanded mesh polyester product fixed with acrylic binder. In this example 
three units of said material, each 64" long, 64" wide and 3" deep, were 
used. In another example two units of the material were used, each 
measuring 60" long, 60" wide and 3" deep. 
In another example particularly designed to provide edge support for the 
waterbed mattress user, a waterbed mattress 84" long, 60" wide and 9" deep 
was employed. The polyester fill which was provided comprised two units 
each 60" long, 60" wide and 3" deep. The units were connected to form a 
single unit. 
In yet another example, a waterbed mattress 63" long, 45" wide and 51/2" 
deep was provided with a fill comprising four ounds of polyester fiber 
that was non-woven and unbonded. 
In still another example, a waterbed mattress 63" long, 41" wide and 6" 
deep was provided with three units of a fiberglass fill each 60" long and 
40" wide and 2" deep. The units were connected to form a single unit. 
In all units the fill formed a mesh-like obstacle in the contained water 
volume which effectively inhibited and dissipated wave movement. 
In the foregoing examples the waterbed mattress is unmodified. However, an 
alternate embodiment is also encompassed by the present invention. Thus 
the bag-like enclosure which constitutes the waterbed mattress can be 
provided with flotation means along its margin thereby providing edge 
support to the user sitting on the edge of the bed as described in 
Applicant's U.S. Pat. No. 3,864,768. More specifically, the waterbed 
mattress can be provided with a peripheral pneumatic float tube, which, 
when air filled, provides buoyant edge support around the upper periphery 
of the waterbed mattress. This peripheral pneumatic float tube is provided 
with an air inflation tube which penetrates the waterbed mattress whereby 
it may be filled. Turning in detail to the drawings, FIGS. 1, 2 and 3 show 
a waterbed mattress of the present invention provided with fiber product 
loosely distributed throughout the mattress. The drawings show relatively 
even distribution of the fiber product. In operation the fiber product, 
particularly unbonded fiber product, may be massed or clumped in part 
and/or form voids in part. As hereinbefore set forth and as demonstrated 
by the drawings, the present invention includes the employment of unbonded 
fiber and/or bonded fiber, i.e., fiber fixed with a binder. As previously 
stated the fiber product, such as that depicted in the drawings, may 
appropriately have a density of about 0.5 to 0.2 pounds per cubic foot 
though the invention is not limited to that density. The foregoing weight 
per unit volume of the body of lofted material is not to be confused with 
the weight per unit volume of each unlofted fiber taken alone, the binder 
taken alone or a skrim taken alone. Each of these materials possesses its 
own distinct weight per unit volume, as distinguished from the weight per 
unit volume of the body of lofted fibrous material disposed at any desired 
location within the waterbed mattress to inhibit wave action. When a 
bonded fiber is used it may be more dense because of the employment of 
greater quantities of binder. The amount and composition of binder can 
vary without departing from the scope of the present invention. As also 
previously indicated, the fibers are expanded i.e., the fibers as used for 
purposes of the present invention are spaced apart in relation to each 
other though they randomly touch one another.