A flotation mattress comprising an outer jacket of supple flexible sheet plastic having normally flat vertically spaced top and bottom walls and vertical side and end walls and a plurality of elongate bladders of supple flexible sheet plastic with top, bottom, side and end walls arranged within the jacket in parallel side-by-side relationship with each other and slackly filled with water, the dimensions of the related and assembled bladders being substantially the same as the dimensions of the jacket whereby the bladders are captively retained in assembled relationship and are reinforced by the jacket. The jacket has a plurality of elongate, vertical parallel partitions, each occurring between a pair of adjacent bladders and stopping displacement of the bladders within the jacket.

This invention has to do with a flotation mattress and is particularly 
concerned with a novel mattress structure for articulated beds. 
BACKGROUND OF THE INVENTION 
In the art of beds, the most common form of bed comprises an elongate, 
flat, horizontal, rectangular body supporting mattress of soft, resilient 
and/or yielding material and an elongate floor engaging bed frame arranged 
beneath and supporting the mattress above the floor. Such beds have 
forward head ends and rear foot ends. 
One special class of bed, which is widely used in hospitals and the like, 
includes an articulated mattress supporting frame which is such that it 
can be operated to elevate the head end of the mattress whereby the head 
end portion of the mattress is longitudinally and upwardly inclined 
relative to the remainder of the mattress and so that a person lying or 
engaged on the mattress is comfortably supported in a semi- or 
substantially upright sitting position. The ordinary articulated bed of 
the character referred to above is commonly constructed and operable to 
elevate and bend or break that portion of its related mattress occurring 
at and beneath the knees of a person lying on the bed to comfortably 
elevate and support the legs of that person in an elevated bent condition, 
when desired. 
In the ordinary articulated bed frame, the normally horizontal, 
rectangular, mattress supporting frame is a sectional structure comprising 
a head end section, a foot end section and a central or intermediate 
section. The several sections have laterally extending or transverse 
forward and rear end edges. The rear edge of the head section and the 
forward edge of the central section are pivotally connected together on a 
fixed horizontal axis extending transverse the frame, while the rear edge 
of the central section and the forward edge of the foot end section are 
pivotally coupled together on a vertically and longitudinally shiftable 
transverse axis. The rear edge of the foot end section is free to shift 
longitudinally and is, in some instances, shiftable vertically. 
The ordinary articulated bed frame structure of the character referred to 
above also includes manually operable or motor driven jack mechanisms 
related to the head sections of the frames to pivot the forward edges of 
those sections of the frames up and down. Second and similar jack 
mechanisms are provided to raise and lower the pivotally connected edges 
of the central and foot end sections and, if necessary, third similar jack 
mechanisms can be provided to raise and lower the rear edges of the foot 
end sections. 
In the case of ordinary fiber or plastic foam filled fabric covered 
mattresses used in combination with articulated bed frames of the 
character referred to above, the mattresses substantially freely break or 
bend transversely along lines parallel with the axes between the adjacent 
sections of the frames to establish the desired mattress configurations. 
Further, in the art of bedding, flotation mattresses comprising water 
filled bladders of supple and flexible sheet plastic have become quite 
common in recent years and are now recognized as affording support for the 
human body which is notably superior to that support which is afforded by 
common fiber or foam plastic filled fabric covered mattresses. 
The superior body support afforded by flotation mattresses is such that the 
use of such mattresses is being recommended and/or required by an 
ever-increasing number of experts in the fields of medicine and physical 
therapy. 
As a result of the above, in the recent past, efforts have been made to 
support water-filled plastic bladder-type flotation mattresses on 
articulated bed frame structures of the character referred to in the 
preceding and to thereby attain the benefits afforded by flotation 
mattresses in combination with the benefits afforded by articulated bed 
frames. Such efforts have met with little or no success. 
The lack of successful use of flotation mattresses in combination with 
articulated bed frames of the character referred to above resides in the 
fact that ordinary flotation mattresses comprise bladders of soft, supple 
and flexible sheet plastic with vertically spaced normally parallel 
horizontal, top and bottom walls and vertical side and end walls about and 
between the top and bottom walls. The two horizontal walls are established 
of two sheets of plastic sheet stock and the side and end walls are 
normally established by vertically downwardly and upwardly turned and 
suitably cut marginal extensions on the top and bottom walls, which 
extensions have related edges arranged in lapped engagement with each 
other and are sealingly fixed together by continuous lines of thermal 
welding. Accordingly, the side and end walls of such mattresses are 
characteristically interrupted and divided by welded seams. In addition to 
the above noted seams, the four vertical corner edges of such mattresses 
are often established by welded seams. 
When thermally welding the seams in the sheet plastic of mattresses of the 
character referred to above, heat and pressure is applied on and between 
the plastic sheeting to be welded along weld lines. The applied heat and 
pressure stretches, draws and causes the plastic material to flow and weld 
together. The stretching, drawing and/or flowing of the material results 
in notably reducing the wall thickness of the sheet plastic material 
adjacent the weld lines and materially weakens the resulting bladder 
structures adjacent the weld lines. 
The above noted weakened areas of the bladders are subject to rupturing and 
tearing when excessive internal pressures, in the bladders, are 
encountered. 
In addition to the above, thermal welding also tends to cause hardening or 
embrittlement of the welded material to further weaken the resulting 
structures. 
When water filled flotation mattresses of the character referred to above 
arre related to articulated bed frames and are caused to be bent or broken 
along one or more transverse lines by operation of the bed frames, the 
bending or breaking of the mattresses, in effect, squeezes or pinches off 
portions of the mattresses, displacing the water adjacent thereto and 
materially increasing the hydraulic or fluid pressure within the 
mattresses. In the case of ordinary floation mattresses of the character 
referred to above, the increased pressures generated within the mattress 
upon bending or breaking them, as noted above, is sufficient to cause the 
weakened portions of the mattress structures adjacent the weld lines to 
rupture or burst. The above rupturing or bursting of such mattresses 
occurs in spite of the fact that the portions of the mattress which are 
not weakened by welding or the like are theoretically of sufficient 
strength to withstand the noted increased pressures. 
Attempts to overcome the above noted weaknesses in ordinary flotation 
mattresses by increasing the wall thickness of the sheet material employed 
to establish the mattresses and thereby provide a greater amount of 
material and resulting greater strength at the weld lines, has resulted in 
mattresses which are not sufficiently supple and flexible, or which are 
too hard and stiff to afford the sought after and desired body support. 
Another shortcoming found in the use of conventional flotation mattresses 
in combination with articulated bed frames of the character referred to 
above resides in the fact that when the bed frames are operated to bend or 
break the mattresses, the unrestricted flow or displacement of the single 
and large volume of water throughout the planes of the mattresses results 
in situations where insufficient water is let to remain beneath some 
portions of the bodies of persons engaged on the mattresses to prevent 
their bodies from causing the top walls of the mattresses to engage and 
stop or "bottom out" on the bottom walls thereof; and moves or displaces 
excessive volumes of water beneath other portions of the bodies of the 
persons to elevate those portions of their bodies, whereby desired and 
sought after body support is unattainable. 
OBJECTS AND FEATURES OF MY INVENTION 
It is an object and feature of my invention to provide a novel articulated 
water bed. 
Another object of my invention is to provide a novel flotation mattress 
which is particularly suited for use in combination with articulated bed 
frame structures. 
Yet another object of my invention is to provide a flotation mattress for 
use in combination with an articulated bed frame which is stronger and 
more durable, yet substantially as supple and flexible as conventional 
flotation mattresses. 
It is a feature of my invention to provide a flotation mattress of the 
general character referred to above which includes an outer jacket of 
supple, flexible sheet plastic and a plurality of elongate, parallel 
bladders of like material slackly filled with water and arranged within 
and contained by the outer jacket. 
A further object of my invention is to provide a mattress structure of the 
character referred to above in which the outer jacket and the plurality of 
bladders are dimensionally proportioned so that the jacket supports and 
limits or prevents stretching and distending of the bladders beyond their 
elastic limits. 
Yet another feature of my invention is to provide a mattress of the general 
character referred to above wherein the bladders and the jackets are 
established of sheets of thin, supple and flexible plastic material having 
edge portions in lapped engagement with each other and thermally welded 
together by continuous lines of weld and a construction wherein the lines 
of weld in the jacket are offset and spaced from the lines of welds in the 
bladders whereby the portions of the jacket backing up and supporting the 
welds in the bladders are not interrupted and/or weakened by lines of 
welds. 
It is an object of my invention to provide a novel flotation mattress of 
the general character referred to above which is such that when it is 
caused to break or bend by operation of its related articulated bed frame, 
and when certain portions of the mattress structures are elevated above 
other portions thereof, gravity induced displacement and/or flow of water 
within the mattress structure is limited and controlled so that sufficient 
volumes of water remain in the elevated portions of the mattress to afford 
desired body support and the displacement or flow of water to the lower 
portions of the mattress is insufficient to prevent the establishment of 
desired and sought after body support. 
The foregoing objects and features of my invention will be fully understood 
and other objects of my invention will become apparent from the following 
detailed description of typical preferred forms and applications of my 
invention, throughout which description reference is made to the 
accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION 
In FIGS. 1 through 5 of the drawings, I have shown an articulated bed 
structure A with a flotation mattress M and a mattress retainer R related 
to it. 
The bed structure A is not illustrative of any known bed structure and is 
merely intended to show one typical combination and relationship of the 
basic parts that characterizes most articulated beds and with which my new 
mattress M can be advantageously related. 
The bed structure A includes vertical, transversely extending foot and head 
boards 10 and 11 with floor engaging legs, a horizontal rectangular 
primary frame P fixed to and extending between the boards 10 and 11 in 
vertical spaced relationship above a related floor and a sectional 
articulated frame F above and supported by the primary frame P and 
supporting the retainer R and the mattress M. In addition to the above, 
the bed structure A includes two longitudinally spaced jack mechanisms J 
and J' carried by the primary frame P and suitably coupled with the frame 
F. The jack mechanisms J and J' are shown as manually operable mechanisms 
with hand cranks 12 accessible at the side of the bed frame structure A. 
In practice, the jack mechanism can be motor-driven, as desired. 
In the structure A illustrated, the sectional articulated frame F is 
supported by the frame P and includes three longitudinally spaced 
sections, there being a forward head section 14, a rear foot section 16 
and an intermediate or central section 15. The several sections 14, 15 and 
16 are shown as being substantially equal in longitudinal extent; are 
rectangular in plan configuration and have straight, longitudinally 
extending side edges and straight, transversely extending front and rear 
or foot and head end edges. The head end edge of the central section 15 
occurs adjacent an is pivotally connected with the foot end edge of the 
head section 14 and the foot end edge of the central section 15 occurs 
adjacent and is pivotally connected with the head end edge of the foot 
section 16. 
In the case illustrated, the sections 14, 15 and 16 are shown including 
flat, horizontal, rectangular platforms 14', 15' and 16' of plywood and 
the like. The head end and side edges of the head section 14 are defined 
by angle iron frame members 17 and 18. The foot end and side edges of the 
foot section 16 are defined by angle iron frame members 19 and 20 and the 
side edges of the central section 15 are defined by angle iron frame 
members 21. The frame members 17 through 21 have outer vertical flanges 
which, in the case illustrated, project up from the top planes of their 
related platforms to establish retaining flanges for the retainer R. The 
related ends of the outer vertical flanges of the frame members 18, 20 and 
21 establish lapped engagement with each other and are pivotally connected 
together by pivot pins 22 and 23. The pinned together portions of the 
frame members establish hinge means H and H' pivotally coupling the 
adjacent sections 14, 15 and 16 together, as clearly shown in the 
drawings. The pins 22 of the forward hinge means H are engaged in a 
plate-like bracket 24 whereby the hinge means H is held against vertical 
and longitudinal shifting relative to the primary frame P. 
In common or conventional bed structures of the character here concerned 
with, the sections 14, 15 and 16 include metal frames within which bed 
springs comprising flat inner net works of wire links and pluralities of 
coil springs about the net works and engaging the frames, are arranged. 
Accordingly, the frame F which I have elected to illustrate is a different 
or novel frame with which my new mattress structure can be effectively 
related. 
The jack mechanism J is shown related to and is suitably connected with the 
head section 14. The mechanism J is operable to pivot the section 14 
upwardly and forwardly relative to the hinge means H, frame P and the 
central section 15, as clearly shown in the drawings. The jack mechanism 
J' is shown related to and is suitably connected with the section 15 (or 
16). The mechanism J' is operable to pivot the foot end of the central 
section 15 upwardly and rearwardly relative to the hinge means H, the 
frame P and the section 14 and to thereby draw and move the foot section 
16 forwardly and pivot it upwardly relative to the frame P and downwardly 
and forwardly relative to the hinge means H' and the central section 15, 
as clearly shown in the drawings. 
In practice, the form and details of the bed construction thus far 
described can vary widely without adversely affecting or departing from 
the spirit of my invention. 
Referring to FIGS. 1, 2, 3 and 4 of the drawings, the retainer R is a flat, 
horizontal rectangular unit coextensive with and overlying the top of the 
articulated frame F of the bed structure A in supported engagement 
therewith. The retainer R includes a normally flat horizontal rectangular 
panel 25 established of soft, flexible sheet plastic (or an equivalent 
material) and an upwardly projecting rectangular frame like weir 26 of 
soft, resilient and flexible foam plastic (or an equivalent material) 
about the perimeter of and projecting upwardly from the panel 25 and 
cooperating therewith to define an upwardly opening flotation mattress 
receiving and retaining basin X. 
In the form of the invention illustrated, the panel 25 of the retainer has 
marginal extensions which are formed to extend about and to envelope the 
weir 26. With the weir 26 enveloped by integral extensions of the panel 
25, the panel and the weir are integrated in a manner which effectively 
prevents lateral and/or longitudinal displacement of the weir relative to 
the panel 25 and to its related bed frame structure. 
In practice, if desired, the panel 25 can be provided with an underlying 
layer of substrate of foam plastic. 
It is to be noted that with the novel frame structure F that I have shown, 
the lower outside edges of the weir 26 are engaged by the vertical outside 
flanges of the frame members 17 through 21 of the articulated frame F 
whereby the retainer R is effectively retained in supported engagement 
atop the frame F. 
The retainer R is sufficiently flexible so that when it is held down by the 
weight of the water-filled flotation mattress M engaged therein and when 
sections of the frame F are operated from their normal horizontal 
positions to elevated and broken positions, the retainer R bends and 
breaks to maintain uniform supported engagement with the frame F, as 
clearly shown in the drawings. 
Referring to FIGS. 1, 2 and 6 of the drawings the flotation mattress M is a 
flat horizontal rectangular unit substantially corresponding in plan 
configuration and in vertical extent with the basin X defined by the 
retainer R and is arranged within said basin X to be supported by the 
retainer 25 and retained by the weir 26 thereof. 
The mattress M includes an outer jacket O of flexible, supple sheet plastic 
and a plurality of elongate parallel water filled bladders B, of similar 
sheet plastic arranged within the jacket O in captive retained engagement 
therein. 
In practice, the plurality of elongate bladders B within the jacket O occur 
in side by side relationship with each other and can extend longitudinally 
of the jacket O, as shown in solid lines in FIG. 6 of the drawings, or can 
extend laterally of said jacket O, as shown in dotted lines in FIG. 6 of 
the drawings and in solid lines in FIG. 17 of the drawings. 
The provision and use of laterally spaced longitudinally extending bladders 
B within the jacket O requires a lesser number of bladders B than is 
required if the bladders are spaced longitudinally and extend laterally of 
the jacket O and the ability to effectively heat the water in the several 
bladders by a single, laterally extending blanket-type resistance heater 
supported atop one of the platforms is made possible. For these reasons, 
such an arrangement of bladders is preferred. 
While longitudinally extending bladders effect desired and effective 
control of displaced water within the mattress M when portions of the 
mattress are elevated and the mattress is broken along transverse lines, 
the provision and use of longitudinally spaced laterally extending 
bladders affords superior control of gravity displaced water within the 
mattress structure, when it is bent or broken as noted above. The superior 
control of water displacement within the mattress M afforded by a 
longitudinal series of laterally extending bladders is sufficiently great 
to make that arrangement highly desirable and such that it might be 
preferred by certain of those who will practice my invention. 
The outer jacket O of the mattress includes and/or is characterized by 
normally flat vertically spaced horizontal rectangular top and bottom 
walls 30 and 31, vertical side walls 32 and vertical head and foot end 
walls 33 and 34. The jacket O is established of soft, supple and flexible 
sheet plastic, such as polyvinylchloride. 
In the preferred carrying out of my invention, the top wall 30, one end 
wall, such as the foot end wall 34; and a portion of each side wall 32 are 
established of a first single sheet of plastic, cut substantially as shown 
in FIG. 7 of the drawings; while the bottom wall 31, the other or head end 
wall 33, and the other portions of the side wall 32 are established of a 
second single sheet of of like plastic cut substantially as shown in FIG. 
8 of the drawings. 
Referring to FIGS. 7 and 8 of the drawings, the lines L are the bend lines 
along which the sheet material is bent to define the corner edges between 
the several walls of the structure and the lines L' are the bend lines 
along which the sheet material is bent to define the four vertical corners 
of the jacket. The border portions S about the perimeter of the sheet in 
FIG. 7 of the drawings are those flange portions of that sheet which are 
arranged to occur in lapped engagement with related flange portions S of 
the sheet in FIG. 8 of the drawings and which are thermally welded 
together to establish the required seams in the jacket structure. 
In the jacket structure illustrated, there is a seam S' along the junction 
of the bottom wall 31 and the foot end wall 34, a seam S.sup.2 along the 
junction of the top wall 30 and the head end wall 33 and longitudinally 
upwardly and forwardly inclined seams S.sup.3 extending diagonally of the 
side walls 32, from the lower corners of the foot ends to the upper 
corners of the head ends of said side walls. In addition to the seams 
S.sup.1, S.sup.2 and S.sup.3, noted above, the foot end portions of the 
side walls 32 have downwardly and forwardly inclined seams S.sup.4 
extending from the upper foot end corners of the side walls to the seams 
S.sup.3 and have downwardly and rearwardly inclined seams S.sup.5 
extending from the upper head end corners of the side walls to the seams 
S.sup.3. The seams S.sup.1, S.sup.2 and S.sup.3 are established by a 
single continuous thermal weld and the seams S.sup.4 and S.sup.5 include 
continuous thermal welds which join the welds of the seam S.sup.3. 
It is to be noted that the seams S.sup.2 and S.sup.3 at the ends of the 
jacket O extend longitudinally of their related upper and lower corner 
edges of the jacket and that they do not extend into or across the planes 
of their related vertical end walls. It is also important to note that the 
seams S.sup.3 in the side walls 32 extend diagonally thereof so that they 
occur in close proximity to the mean or central horizontal plane of the 
jacket O at those longitudinally spaced points or stations of the jacket 
which occur above the hinge means H and H' of the frame F which supports 
the mattress M is caused to bend or break by operation of the frame F, the 
portions of the seams S.sup.3 at the bend or breaks in the mattress occur 
substantially at or in sufficient close relationship to the mean 
horizontal plane of the mattress that they are substantially unstressed 
longitudinally of the construction. 
It is also to be noted that if the portions of the seams S.sup.3 occurring 
at the bends or breaks imparted into the mattress were spaced a 
substantial distance radially outward from the mean horizontal plane of 
the mattress structure, the seams would be subjected to substantial and 
potentially damaging tensile forces and would interfere and adversely 
affect bending or breaking of the mattress. Also, if the seams S.sup.3, 
occurring at about the bend or breaks imparted into the mattress, were 
spaced a substantial distance radially inward of the mean horizontal plane 
of the mattress at the bends or breaks therein, the seams would be 
subjected to increased compressive forces and would be subject to being 
distorted, crimped and worked in such a manner that work-hardening of the 
material would be accelerated and premature failure of the construction 
would result. 
In accordance with the foregoing and in furtherance of my invention, it is 
an object and feature of the invention to provide a jacket structure of 
the general character described and illustrated wherein seams at the sides 
of the jacket are made to occur at or in close proximity with the central 
or mean horizontal plane of the jacket, at and about the transverse bend 
or break lines extending in and through the jacket. In accordance with the 
foregoing, it will be apparent that the seams S.sup.3 can be made to 
extend along a number of different shaped lines to attain the above end 
and that the straight diagonal seam lines shown in the drawings and 
described above is but one simple and practical way in which the sought 
after end can be attained. 
In practice, the jacket O can, for example, be from 4" to 8" in vertical 
extent, 48" wide and 80" long. 
The dimensions of the basin X of the retainer R are essentially the same as 
the dimensions of the jacket O set forth above. 
The bladders B can be substantially square in cross-section and are 
substantially equal or vary slightly greater in vertical extent than the 
vertical extent of the jacket O. Accordingly, in the example given, the 
bladders may be from about 4".times.4" to about 8".times.8" in 
cross-section. 
Further, the bladders are substantially equal and may be slightly greater 
in longitudinal extent than the longitudinal extent of or than the lateral 
extent of the jacket O, depending upon the direction in which they extend 
within the jacket O. In accordance with the above, with the example given, 
the bladders are approximately 48" or 80" long. 
If the bladders B are 80" long and arranged to extend longitudinally of the 
jacket O, six bladders are provided. If, on the other hand, the bladders B 
are 48" long and are arranged to extend laterally of the jacket, ten 
bladders are provided. 
As shown in the drawings, the several bladders B are alike and each 
includes normally flat horizontal top and bottom walls 40 and 41, vertical 
side walls 42 and like vertical end walls 43. 
Each bladder B is preferably established of a single sheet of soft, supple 
and flexible plastic, such as polyvinylchloride, cut substantially as 
shown in FIG. 11 of the drawings. The lines L.sup.2 in FIG. 11 of the 
drawings are the bend lines which define the 12 corner edges of the 
finished bladder and the border about the perimeter of FIG. 11 is the 
flange material which is provided to establish the required seams in the 
bladder. 
Each bladder includes one longitudinally extending seam S.sup.6 which seam 
can extend diagonally of one side wall 42 as shown in FIGS. 12 and 13 of 
the drawings. Such diagonal dispositioning of the seam S.sup.6 is 
particularly desirable in the case where the bladders B are arranged to 
extend longitudinally of the jacket, for the same reasons that the seams 
S.sup.3 in the jacket O are so inclined. 
When the seams S.sup.6 of the bladders extend longitudinally of the bladder 
and are inclined, as noted above, they are preferably inclined opposite 
with respect to the inclination of the seams S.sup.3 of the jacket. This 
is, for example, rather than being inclined forwardly and upwardly as are 
the seams S.sup.3, the seams S.sup.6 are inclined forwardly and 
downwardly. With this relationship of parts, the seams S.sup.3 in the 
jacket do not occur adjacent and run parallel with the seams S.sup.6 of 
the adjacent bladders, but for the most part are spaced from the seams 
S.sup.6 and occur on axes that only cross each other at one point 
intermediate the ends of the mattress construction. 
The end walls 43 of each bladder are alike and each, for example, can be 
established of four suitably cut and formed flaps at the ends of the four 
longitudinally extending walls 40, 41 and 42; substantially as shown in 
FIG. 11 of the drawings. 
The noted flaps are secured and sealed together by thermal welded seams 
S.sup.7, as shown in FIG. 13 of the drawings. 
With the bladder structure B noted above, when the plurality of bladders 
are arranged to extend longitudinally of the jacket, in side by side 
relationship, the side seam S.sup.6 of each bladder which occurs adjacent 
another bladder is backed up and supported by the side wall of a bladder 
which is not interrupted and/or weakened by a welded seam. Further, the 
end walls 43 with their seams S.sup.7 are backed up and supported by the 
head end and foot end walls 33 and 34 of the jacket O. The end walls 33 
and 34 of the jacket are not interrupted and/or weakened by any welded 
seam and are such that they afford effective backing and reinforcement for 
the seams S.sup.7 at the ends of the bladders. 
In the case where the bladders B are arranged to extend laterally of the 
jacket O and are not subject to being bent or broken intermediate their 
ends, their longitudinal seams S.sup.9 are preferably arranged to occur at 
and extend longitudinally of the lower edge of one of the side walls, as 
shown in dotted lines in FIGS. 11, 12 and 13 of the drawings. With such an 
arrangement, the side seams S.sup.9 are not subject to appreciable working 
when the structure is in use. 
In addition to the above, each bladder B is provided with a suitable water 
conducting filler fitting D to enable the bladder to be slackly filled 
with water. The jacket O is provided with an air evacuating or vent 
fitting E to allow air within the jacket to be vented therefrom when the 
bladders are filled and thereafter evacuated therefrom to draw and urge 
the jacket into substantial uniform engagement with the surfaces of the 
bladders which oppose it. 
The filler fittings D and vent fitting E can vary widely in form. In FIG. 
15 of the drawings, I have shown one form of fitting D and one form of 
fitting E that are satisfactory for carrying out my invention. The fitting 
D is sealingly engaged with and extends through an opening 50 provided in 
the top wall or the jacket O and an opening 50' provided in the top wall 
40 of the bladder B, adjacent one end of the bladder. The fitting D 
includes an elongate flexible tubular neck 51 with a large diameter 
upwardly opening upper end portion and normally depending downwardly and 
into the interior of the bladder and an elongate lower end portion of 
reduced diameter which is turned upwardly into the upper portion and is 
normally closed by a removable plug 52. The neck 51 is such that the lower 
portion of the neck and its related plug 52 normally occur within the 
upper portion of the neck, below the top plane of the mattress and can be 
pulled vertically upwardly to project above the top plane of the mattress 
for convenient access to and removal of the plug 52 and for free access to 
the open free end of the neck when filling the bladder with water. 
The vent fitting E shown in FIG. 15 of the drawings includes a simple 
disc-like body 55 sealingly fixed to the top wall 30 of the jacket O to 
overlie and/or project through an opening 56 provided in that wall. The 
body 55 has a central vertical through opening in which a suitable plug 57 
is removably engaged. The fitting E is sufficiently flat and of limited 
vertical extent so that it is normally substantially flush with the top 
plane of the panel 30 and depends from that panel a limited distance so 
that it will not interfere or adversely affect the bladder B which occurs 
beneath it. 
As the bladders B are slackly filled with water by introducing water into 
them through their fittings D, the fitting E is open to allow air within 
the jacket to be displaced therefrom. When the several bladders are filled 
and the fittings D are plugged and sealed and before the fitting E is 
plugged and sealed, excess air can be evacuated from within the jacket to 
cause the jacket to move into intimate contact with and about the bladders 
and to eliminate pockets of free air within the jacket which might migrate 
about and adversely affect the construction. 
In practice, and to assure desired free relative movement of the bladders B 
relative to each other and relative movement between the jacket and the 
bladders, the exterior surfaces of the bladders and the interior surfaces 
of the jacket can be coated with a suitable lubricant such as talcum 
powder, a suitable silicone lubricant, or the like. 
Finally, the mattress M can be provided with an anchoring means G at the 
head end of the jacket O to releasably anchor that end of the mattress to 
the retainer R or to the frame F, to prevent the mattress from shifting or 
moving axially toward the foot end of the frame F and the retainer R when 
its head end is elevated by the frame F, as shown in FIG. 2 of the 
drawings. 
The anchor means G is shown as including a longitudinal extension 60 on the 
top wall 30 of the jacket O. The extension 60 is engaged over and down the 
outside of the head end of the retainer R. The lower free end portion of 
the extension is releasably secured to the retainer by suitable fastening 
means I. The fastening means I preferably includes a first strip of fabric 
with a looped pile fixed to one part, for example, to the extension 60, 
and a second strip of fabric with a hooked pile fixed to the other of said 
parts, or retainer, and releasably engaging the looped pile of the first 
strip. The above noted form of fastening means is that form of fastening 
means which is sold under the tradename "Velcro". 
With the construction described above and shown in the drawings, when the 
mattress is bent or broken transversely by pivotal movement of the 
sections of the articulated frame F and by operation of the jack means J 
and/or J', increased internal hydraulic pressures in the bladder tend to 
cause the bladders to stretch and to expand. If such expansion and 
stretching of the bladders is unchecked, the bladders are subject to and 
are likely to rupture or burst at their weakest points, that is, adjacent 
to one or more of their thermally welded seams. 
With the construction that I provide, the jacket O about the bladders 
securely holds and backs up the bladders when they are caused to expand by 
increased internal hydraulic pressures. More particularly, the jacket O 
directly backs up and supports the seams of the bladders which it engages 
and prevents these seams or the plastic sheet stock adjacent to the seams 
from stretching or being distended to or beyond its elastic limits. 
In the form of my invention when the bladders are arranged longitudinally 
of the jacket to extend transversely thereof, as shown in dotted lines in 
FIG. 6 of the drawings and as shown diagrammatically in FIGS. 16 and 17 of 
the drawings, when the mattress structure is bent or broken along 
transverse lines by pivoting and elevating portions of the mattress, upper 
or elevated bladders are supported or held up by their next adjacent lower 
bladders and the volumes of water at and occurring at various 
longitudinally spaced portions of the mattress structure remain 
substantially constant. That is, there does not occur a gravity induced 
flow and displacement of water from the elevated portions of the mattress 
down to the lower portions of the mattress; which displacement of water 
would tend to cause the upper or elevated portions of the mattress to be 
left with insufficient water to afford desired conforming of the elevated 
portions with portions of a person's body engaged therewith, or the 
over-filling and/or inflating of the lower portions of the mattress, by 
displaced water, which would prevent the lower portions of the mattress 
from satisfactorily conforming to portions of a person's body engaged 
therewith. 
In the above considered embodiment of my invention, each bladder B is 
slackly filled with water to the extent that each bladder affords 
independent desired conforming support of a portion of a person's body 
engaged therewith. That is, the support afforded by each bladder is 
substantially independent of the support afforded by each of the other 
bladders and yet, the several bladders cooperate with each other to 
provide substantially uninterrupted uniform support of a single body atop 
the mattress and having portions in supported relationship with a 
plurality of all of the bladders. 
In practice, due to the shape and relative proportioning of the jacket and 
the bladders and due to the inherent slack and flexibility of the mattress 
structure, there exists a tendency for the adjacent bladders to slide 
and/or shift over and under each other in such a manner that they may 
become so displaced that the mattress is rendered ineffective. That is, 
there may be a tendency for the bladders to shift down from elevated 
portions of the mattress and to gather together at the lower portions of 
the bent or broken mattress structure. If, if any mattress embodying my 
invention, the above undesirable shifting of the bladders is to be guarded 
against, the jacket O can be and is preferably provided with flat, 
vertical partitions P between each adjacent bladder B, as clearly shown in 
FIG. 18 of the drawings. The partitions P are established of strips of the 
same sheet plastic stock employed to establish the jacket and the 
bladders. The partitions P having upper and lower flanges welded to their 
related top and bottom walls 30 and 31 of the jacket, as illustrated at 
S.sup.10 in FIG. 18 of the drawings. 
With the partitions P noted above, the bladders B are effectively held 
against displacement in the jacket. Additionally, the partitions P afford 
reinforcement of the jacket structure and supplemental support of the 
bladders. 
In FIGS. 10 and 14 of the drawings, I have shown two basic forms of welded 
seams commonly employed in the establishment of water bed mattresses. The 
seam S shown in FIG. 10 and which has been shown employed in the jacket O 
is referred to as a butt seam, while the seam S.sup.6 shown in FIG. 14 of 
the drawings and which has been shown employed in the bladder B is 
referred to as a lap seam. In practice, lap seams are stronger and are 
used when such seams can be effectively established. Butt seams are, as a 
general rule, employed in those situations where lap seams cannot be 
effectively established. 
It is to be noted that the welds in the seams S and S.sup.6 results in a 
reduction of the wall thickness of the sheet plastic stock at the seam (at 
both sections of the weld line). It is this noted reduction in wall 
thickness that adversely affects and notably weakens the finished 
structure. 
Having described only typical preferred forms and applications of my 
invention, I do not wish to be limited to the specific details set forth 
above but wish to reserve to myself any modifications and/or variations 
that may appear to those skilled in the art and which fall within the 
scope of the following claims: