Soft rail waterbed

A waterbed frame is formed of side rails having inner rigid support elements surrounded by resilient cushion material. All sides of the frame may be formed by such rails with the rigid elements being connected at the corners, so that the rigid elements are in effect floating in the cushion material. Alternatively, two such side rails may be attached to more conventional appearing foot and head boards.

This invention relates to an improved waterbed frame construction and more 
particularly to an arrangement which provides the necessary lateral 
support for a waterbed mattress and yet is very comfortable when sat upon 
and not uncomfortable when bumped. 
Waterbed mattresses were initially utilized without side supports or else 
were positioned in a simple wooden frame. It is preferable that the sides 
of the mattress be supported by a frame but the plain wooden frames have 
proved to be unsatisfactory because they are uncomfortable to sit on or to 
bump against. Also, there is a tendency for a person to roll into an 
uncomfortable position somewhat between the frame and the edge of the 
mattress. As a result of this, various improvements have been devised such 
as a padded cap for a wooden rail or a frame made of large foam members. 
Some arrangements include inner side walls which slope downwardly and 
inwardly towards the horizontal support for the mattress so that there is 
additional edge support for the mattress and the amount of water needed is 
reduced. Despite such improvements, a need still exists for a frame which 
maximizes comfort while providing adequate rigidity. 
In accordance with the present invention, the side frame members are 
basically made of a cushion material such as plastic foam or foam rubber 
with a rigid element inserted or embedded within the foam. The cushion 
material extends above the rigid element and is positioned on the outer 
side of the element so that the frame is comfortable to sit on and a 
person is prevented from hitting the hard insert. Additionally, the 
cushion material extends beneath the rigid element, which provides a 
number of advantages. 
An entire frame may be formed of such frame members with the rigid elements 
joined at the corners of the frame. This provides the necessary lateral 
support for the water mattress, which is lacking in many of the all foam 
frames on the market. With the cushion material extending beneath the 
rigid elements, the rigid frame is in effect floating on cushion material; 
thus, the rigid element provides some support when the frame is sat upon 
but yet it is very yielding and hence, is comfortable. This is in contrast 
with those arrangements having a rigid side support element which rests 
directly on a rigid horizontal support surface for the mattress. When a 
rigid element is supported directly on the horizontal support surface, it 
is necessary to have very thick cushioning material above the rigid 
element in order to provide sufficient comfort. This however, detracts 
from the lateral support of the frame since the upper part of the mattress 
is not adequately supported by the cushioning material and extends above 
the rigid side elements. Thus, positioning the rigid elements in the 
manner of the present invention maximizes the comfort of the frame as well 
as the support aspect. 
Another distinct advantage of side frame members of this type is that they 
can be used with head boards and foot boards which appear like the 
headboards and footboards used with conventional, non-water mattress. That 
is, two of the side members of the type described above may have their 
ends connected to the head board and foot board to complete the frame for 
the water mattress. The rigid support elements within the frame members 
may be attached to the foot and head boards in a manner that permits the 
rigid elements to move vertically to provide the floating aspect, while 
they are restrained laterally by the mounting arrangement to provide the 
necessary lateral support.

Referring now to FIG. 1, there is shown a waterbed which includes a large 
support base 10 having positioned thereon a large horizontal rectangular 
support platform 12 with a bag containing liquid forming a waterbed 
mattress 14 supported on the platform 12. The mattress 14 is confined 
within a rectangular frame 16 which extends adjacent and supported on the 
periphery of the horizontal platform 12. 
As seen from FIG. 2, the frame 16 includes an outer rail or member 18 
having a rectangular cross-section and an inner member 20 having the 
cross-section of a right triangle with the base 20a of the triangle 
resting on the support platform 12. The vertical edge 20b of the 
triangular member engages the inner wall 18b of the outer frame member 18. 
The inner wall 20c of the inner frame member 20 angles upwardly and 
outwardly from the platform 12 and engages the edge of the mattress 14. 
The frame members 18 and 20 are formed of suitable resilient cushion 
material, such as polyurethane foam or rubber foam, with the exception 
that the outer member 8 has a board or other rigid element 24 embedded 
therein which extends throughout the length of the member 18. As can be 
seen from FIG. 2, the board has a rectangular cross-section and is 
oriented with the longer side of the board extending vertically. The board 
is positioned within a groove on the inner wall 18b of the cushion member 
18 with the board being approximately centered between the bottom wall 18a 
and the top wall 18c of the cushion member. The height of the cushion 
member is approximately twice that of the board with the result that 
approximately a quarter of the thickness of the cushion member 18 extends 
above the board and another quarter of the thickness extends below the 
board. Thus, the board is in effect floating in the resilient foam. The 
width of the board is less than half the width of the cushion 18 so that a 
thick layer of cushion material extends between the board and the outer 
wall 18d of the cushion member. The side of the board facing towards the 
mattress 14 is in contact with the outer wall 20b of the inner frame 
member 20. 
As seen from FIG. 1, the frame 16 includes a pair of side frame members and 
a pair of end members arranged in the form of a rectangle. The ends of the 
frame member are suitably beveled to mate with each other and the ends of 
the boards within the frame members are attached by suitable means at the 
corners as is illustrated at one corner 26 in FIG. 1. 
With the frame as described, the edges of the mattress 14 are suitably 
supported and restrained. The inner triangular members 20 cause the edge 
of the mattress to conform to the inner angled wall 20c of the frame 
member so that the edge of the mattress is firmer than an interior 
section. The inner triangular section frame member 20 is of course 
restrained by the outer section and particularly by the rigid frame formed 
by the boards 24. Since the inner frame member 20 is separate from the 
outer member 18, it can absorb more action from the mattress somewhat 
independently from the outer frame 18. Thus, it has a motion dampening 
effect. 
The cushioning of the outer frame 18 surrounding the board 24 adequately 
protects a person from being injured or uncomfortable when bumping against 
the frame member. Note in this regard that a portion of the outer frame 
member 18 extends beyond the support platform 12 so that if a person's 
foot should extend beneath the platform, his shin is going to strike the 
cushion material as opposed to the edge of the platform 12. However, the 
board is vertically aligned with the edge of the platform so that when a 
person sits on the frame the platform 12 in combination with the board and 
the cushioning material above and below the board provide adequate 
support. The cushioning material however, results in a yielding support, 
since the entire frame formed by the boards can be moved downwardly 
towards the platform by compressing the cushioning material beneath it. 
The amount of cushioning material above the board in combination with the 
yielding support below is adequate to provide the necessary comfort. 
At the same time, the board extends upwardly approximately three-quarters 
of the distance of the height of the frame so that it provides adequate 
side support for the mattress. It is only the upper quarter of the frame 
which is not backed by a rigid element, and of course the outward forces 
that may be transmitted through the water mattress are greater in the 
lower portions of the mattress than on the upper portion. Thus, the frame 
for the mattress utilizes a unique combination of rigid support along with 
padded comfort. 
The arrangements of FIGS. 3-5 illustrate the versatility of the design, 
employing different forms for the rigid element. FIG. 3 is identical to 
that of FIGS. 1 and 2 with the exception that the board in the frame 
member has been replaced by an extruded channel member 30 which may be 
made of metal or plastic as well as wood. As seen, the legs of the channel 
member conveniently extends into an outer cushion member 31, with the 
other side of the channel facing the cushion member 20, although the 
reverse arrangement could be employed. 
In the arrangement of FIG. 4, a rigid element 32 has a cross-sectional 
shape which is similar to the overall shape of a frame member 34. The 
cushioned frame member 34 is made as a single piece as opposed to the 
inner and outer arrangement of FIG. 2. This construction has certain 
manufacturing advantages in that the entire frame member may be extruded 
in one operation with the rigid element 32 being made of a suitable 
plastic material. Thus, the entire frame member may be made as a 
continuous extruded item and then cut to the desired lengths. 
Alternatively, the foam may extrude around a wooden core. 
The arrangement of FIG. 5 is identical to that of FIG. 2 with the exception 
that a rod 36 of circular cross-section forms the rigid element and 
provides the support function of the board 24. The rod provides slightly 
less lateral support than the board since it does not extend as far 
vertically but it provides somewhat greater cushioning and also may have 
some manufacturing advantages. 
One of the features of the frames illustrated in FIGS. 2-5 is that they can 
not only be utilized in the arrangement shown in FIG. 1, but they may also 
be used with more conventional head and foot boards. Thus, in FIG. 6, the 
end of a side frame member 18, having a construction like that of FIG. 2, 
is shown attached to the corner post 40 of a head board 41. More 
specifically, the board 24 is attached to the corner post 40 by suitable 
means. The other end of the insert board 24 is similarly attached to a 
foot board (not shown). The head and foot boards themselves may form the 
supporting frame members for the edges at the head and foot of the 
mattress. If desired, triangular shaped frame members 20 may be positioned 
adjacent the head and foot boards to correspond to the side frame members. 
With the arrangement shown in FIG. 6, the vertical movement of the side 
board 24 is very minimal since the ends of the board 24 are attached to 
the head board and the foot board. However, with the arrangement shown in 
FIG. 7, the board 24 is laterally restrained but can move vertically so 
that it is floating in the same manner as in the arrangement of FIG. 2. 
Any suitable connection which will permit the vertical movement while 
providing lateral restraint may be utilized to connect the side board 24 
to the head board. In FIG. 7, a bracket 42 is shown attached to the corner 
post 44 with the bracket having a central portion 46 spaced outwardly from 
the post and such central portion having a pair of vertically oriented 
slots 48. A pair of screws 50 or other such elements are positioned in the 
end of the board 24 with the heads of the screws extending outwardly to be 
received within the enlarged openings 48a at the upper ends of the slots 
48. The frame member 18 is positioned at rest on the platform 12 so that 
the shanks of the screws 50 are positioned below the openings 48a at the 
upper ends of the slots so that the screw shanks are laterally restrained 
and the end of the board is captured adjacent the post. 
There are a number of additional advantages of the mattress support system 
described above that may not be readily apparent. A generally flat 
electric heating element or pad (not shown) is commonly positioned beneath 
a waterbed mattress. The cord supplying power and the cord for controlling 
the power supply are connected to the heater and must be accessible from 
the exterior of the mattress. With resilient material extending beneath 
the rigid element 24, the cords for the heater may simply extend beneath 
the side frame members without being damaged. This is in contrast with 
frames having rigid elements directly on the supporting platform. 
Another advantage of the system described above is the manner in which it 
cooperates with the bedding and a mattress liner (not shown). The liner 
extends beneath the mattress, between the side surface 20 and the edge of 
the mattress, around the outer surface of the frame member 18, and then 
between the frame member and the platform. 
The bedding extends over the mattress and the frame members and is then 
captured between the frame members and the platform. This is essentially 
the same manner that bedding for a more conventional mattress is captured 
between the mattress and the box spring. This approach is more convenient 
than trying to position bedding beneath the waterbed mattress itself, or 
between a mattress and its frame. Finally, a skirt can be attached to the 
edge of the platform 12 giving the bed the appearance of a box spring and 
mattress type bed.