Apparatus for making water bed mattresses

A water bed mattress comprised of upper and lower flexible foldable sheets which are essentially rectangular in shape. The upper sheet is essentially formed by folding up portions of the lower sheet upwardly and inwardly and transversely sealing end margins of the folded up portions, and also thereby creating two peripheral transversely extending side wall sections. In addition, longitudinal end portions of the upper and lower sheets are also folded downwardly and upwardly, respectively, and sealed to each other to thereby form longitudinally extending side wall sections, and which, together with the upper and lower sheets, create an internal water chamber. In the making of the water bed mattress, end cut-outs are formed in the sheets. Moreover, insert panels are heat-sealed to the interior portions of the side wall sections to cover these cut-outs and thereby seal the interior of the mattress. In accordance with this construction, a water bed mattress can be formed with a minimum amount of material and which creates less seaming area and locates the corner areas in a position away from the frame which supports the water bed mattress. The present invention also provides a method and an apparatus for making the water bed mattress.

BACKGROUND OF THE INVENTION 
This invention relates in general to certain new and useful improvements in 
water bed mattresses and the method and apparatus used in making the same, 
and, more particularly, to improved water bed mattresses and the method 
and apparatus used in making the same, which are constructed with a unique 
seam construction to thereby minimize the seaming area and stresses on the 
mattress. 
In recent years, water beds have become widely commercially acceptable and 
have found substantially increased use. It is now being fairly well 
recognized that water beds, that is those forms of beds which employ a 
water-filled mattress, have not only enjoyment value, but therapeutic 
value as well. In general, it has been found that many people find that it 
is not only more enjoyable, but is more restful to sleep on a water bed 
mattress than other forms of conventional mattresses filled with solid, 
but nevertheless resilient, material. 
Due to the increased acceptance of water beds, there have been a number of 
proposed techniques in the construction of these water beds and in the 
proposed techniques for the manufacture of such water beds. One of the 
primary problems involved is the sealing of the components of the water 
bed mattress, which normally comprise vinyl plastic components in such 
manner that they will not yield under stress. Moreover, it has been found 
in connection with the manufacture of such water bed mattresses that a 
substantial amount of waste material results, particularly in the 
formation of the corner margins in the rectangularly shaped water beds. 
Notwithstanding, in order to form the corner margins, some manufacturers 
have resorted to pleating and like gathering of materials in order to 
hopefully reduce the stresses on the corner margins. Nevertheless, the 
typical techniques used in the manufacture of water beds also require a 
substantial amount of manual labor which thereby lends to an increase in 
the cost of such mattresses. 
The present invention obviates these and other problems in the provision of 
a water bed mattress which is constructed of a pair of upper and lower 
sheets with a pair of transverse side walls being formed by forming the 
lower sheets into upper panels and sealing the upper panels to form the 
upper sheet. Moreover, longitudinal side flaps on the upper and lower 
sheets are struck downwardly and upwardly, respectively, in order to form 
the longitudinal side wall sections. 
In addition, cut-outs are formed in the longitudinal side walls and panels 
are lap-sealed to the side wall sections having these cut-outs as well as 
to the adjacent side wall sections. In this way, it is possible to 
manufacture the water bed on a relatively simple basis involving a minimum 
amount of manual labor and a minimum amount of waste material. 
It is therefore the primary object of the present invention to provide a 
water bed mattress which is formed with improved corner margins by unique 
use of lap-sealing and which thereby eliminates possible stress on the 
seams of the mattress and thereby increases the longevity of the mattress. 
It is another object of the present invention to provide a water bed 
mattress of the type stated which utilizes a minimum of seam welds and 
thereby substantially reduces the possibility of leakage problems. 
It is a further object of the present invention to provide a water bed 
mattress of the type stated which is highly durable in its construction 
and provides a safety feature substantially greater than other forms of 
conventional available water bed mattresses. 
It is also an object of the present invention to provide an apparatus to 
aid in the formation of unique corner margins in water bed mattresses. 
It is another salient object of the present invention to provide a method 
of making a water bed mattress of the type stated which is highly 
efficient in its operation and requires a minimum amount of manual labor. 
With the above and other objects in view, my invention resides in the novel 
features of form, construction, arrangement and combination of parts 
presently described and pointed out in the claims.

DETAILED DESCRIPTION 
Referring now in more detail and by reference characters to the drawings 
which illustrate practical embodiments of the present invention, A 
designates a water bed mattress comprising an upper flexible plastic sheet 
10 and a lower flexible plastic sheet 12, and both of which are 
substantially orthagonal, and preferably rectangular in their 
construction, but also preferably with rounded corner margins. 
The upper sheets 10 which serves as a top wall is connected to the lower 
sheet 12 along its transverse end margins by means of transversely 
extending side wall sections 14 which are integral with the upper sheet 10 
and the lower plastic sheet 12. In this case, the lower plastic sheet 12 
also serves as a bottom wall. Moreover, the lower plastic sheet 12 
actually is formed of two inwardly struck bottom wall panels extending 
from the side wall sections 14 and which are heat-sealed by a transverse 
heat seal designated by reference numeral 16. 
The water bed mattress A is also provided with a pair of longitudinal side 
wall sections 18 in the manner as illustrated in FIGS. 1 and 2 of the 
drawings. In this case, the longitudinal side wall sections 18 are formed 
by means of a downwardly struck flap 20 on each of the longitudinal side 
margins of and are integral with the upper sheet 10, and upwardly struck 
flaps 22 which are integral with and extend longitudinally along the two 
panels which form the bottom or lower sheet 12. Moreover, each of the 
downwardly struck flaps 20 and the upwardly flaps 22 are lap-sealed along 
their longitudinally common margins by means of a lap-seal designated by 
reference numeral 24, and as more fully illustrated in FIG. 2 of the 
drawings. 
The upper sheet 10 may also be provided with a suitable valve 26 which is 
essentially conventional in the construction of water bed mattresses, and 
it will therefore not be described or illustrated in any further detail 
herein. These valves 26 are designed to permit the filling and removal of 
water into the interior chamber formed within the water bed mattress. 
In order to form corner sections, as illustrated in FIG. 2, without the 
necessary pleating normally resulting from this form of construction, the 
water bed mattress is provided with a panel insert, designated by 
reference numeral 28, which extends over apertures at each of the opposite 
ends of each of the longitudinal side wall sections 18. In this case, each 
of the insert panels 28 are provided with inwardly struck terminal flanges 
30 for lap-sealing to the respective top wall 10 and the bottom wall 12 
and the transverse side wall sections 14, in the manner as illustrated in 
FIG. 2 of the drawings. Moreover, the insert panel 28 is also provided 
with a vertical lap seal 32 to seal the inner end of the insert panel 28 
to the longitudinal side wall sections, in the manner as illustrated. 
As indicated above, FIGS. 3-11 also show portions of the details of 
construction of the water bed mattress A and also illustrate the sequence 
of method steps used in the manufacture of the water bed mattress. 
Reference numeral 40 illustrates a flat sheet having a length 
approximately equal to the total longitudinal dimension of the top wall 
and the bottom wall and the overall height of each of the transverse side 
wall sections 14. Moreover, the flat sheet 40 is provided with 
longitudinally extending fold lines designated by reference numeral 42, on 
each of the opposite transverse sides thereof to thereby create the 
upwardly and downwardly struck longitudinal flaps 20 and 22. In addition, 
the sheet 40 is provided with a first pair of transversely extending fold 
lines 44 located toward one transverse end margin of the sheet 40, and 
another pair of transversely extending fold lines 46 located near the 
other opposite end margin of the sheet 40. These transversely extending 
fold lines 44 and 46, and more particularly the area between each fold 
line of the pairs, form the respective transversely extending side wall 
sections 14. In addition, the outermost fold line of each of the pairs of 
fold lines 44 and 46 define the two inwardly struck lower panels 
designated by reference numerals 48, which thereby form the bottom sheet 
12. 
After the sheet 40 is laid out in a relatively flat position on a table or 
similar support surface, which has been cut to a proper length, four 
rectangularly located indicia marks, designated by reference numeral 50, 
are marked on the upper surface of the sheet 40. These indicia marks 
represent the desired location for removing portions of the sheet and 
thereby create four rectangularly spaced cut-outs 52 which may be provided 
with somewhat rounded corner margins 54 on the inner portions thereof. 
Moreover, it can be observed that these cut-outs 52 transversely span the 
first pair of transversely extending fold lines 44 and the second pair of 
transversely extending fold lines 46. 
As the next step in the making of the water bed mattress, the inwardly 
struck panels 48 which ultimately form the bottom wall 12 are folded 
inwardly around the respective fold lines 44 and 46. In this case, the 
panels 48 are folded inwardly in upwardly spaced apart relationship with 
respect to the sheet 40. However, ultimately, this structure including 
these panels are inverted to form the bottom wall. FIG. 5 illustrates the 
panels 48 folded and aligned with the transverse terminal margins lying in 
juxtaposition to one another but not having been end sealed. 
After the sheet 40 is folded in the position as illustrated in FIG. 5, the 
four insert panels 28 are then connected to the folded sheet 40 in the 
region of the cut-outs 52. By reference to FIGS. 4 and 6 of the drawings, 
it can be seen that the panel 28 and the cut-outs 52 essentially have a 
similar shape. However, the size of the cut-outs 52 is slightly larger 
than the panels 28, in the initial unfolded condition. In addition, the 
cut-outs 52 could be essentially rectangular in shape whenever the insert 
panels 28 have rounded corner margins. The insert panels 28 are initially 
provided with an inwardly struck flange 30 along a portion of its 
periphery. When the sheet 40 is folded in the position, as illustrated in 
FIGS. 8-10, it can be observed that each particular cut-out 52 assumes 
essentially the same overall size and shape as the flat portion of insert 
panel 28. Moreover, the flange 30 extends along a portion of what is then 
the top wall 10 and a portion of the bottom wall 12, as well as a portion 
of the associated transversely extending side wall sections 14. In such 
position, the flange 30 is then sealed to these respective portions of the 
sheet 40. Moreover, by simple observation to FIGS. 8-10, it can be 
observed that the sealing between the insert panel 28 and the sheet 40 
assumes that of a lap seal. Moreover, and in this same respect, it can be 
observed that each of the four insert panels 28 would be located and 
sealed to the sheet 40 at a respective one of each of the cut-outs 52. 
After each of the insert panels 28 have been heat-sealed in their position, 
the longitudinal side flaps 20 on each of the opposite sides of the top 
wall 10 are folded downwardly and, similarly, the longitudinal flaps 22 on 
the lower panels which form the bottom wall 12 are struck upwardly. 
Thereafter, a metal bar serving as an RF conductor is inserted in the 
interior portion of the mattress being formed. In this respect, it can be 
observed that one of the longitudinal flaps 20 or 22 will overlie the 
other of the longitudinal flaps. In this case, the two flaps are then 
lap-sealed to each other on each of the opposite sides of the mattress to 
thereby complete the formation of the side wall components. After 
formation of the two longitudinal side wall sections, the steel conductor 
can be removed from the apertures still existing between the longitudinal 
side wall sections and the insert panels. 
After the longitudinal side wall sections have been formed, as described in 
connection with FIG. 9, the end margins of the longitudinal side wall 
sections are then heat sealed to the inwardly presented end of the insert 
panel 28 and are heat-sealed along a vertical heat seal designated by 
reference numeral 56. In this way, the formation of a completely enclosed 
peripheral side wall is achieved. In this last respect, it should be 
observed that the RF conductive bar which is used in the formation of the 
vertical lap seal 56 on each of the four corners of the mattress can be 
removed between the opening existing between the two inwardly struck 
panels 48 to form the bottom wall 12. 
As a final step in the formation of the water bed mattress, the two 
inwardly struck panels 48 are then heat-sealed by means of a lap-seal 58, 
as more fully illustrated in FIG. 11 of the drawings. In this respect, it 
can be observed that the free margins of the inwardly stuck panels 48 
overlap with respect to each other to thereby enable the formation of a 
lap seal. The metal RF conductor which is used in the formation of the lap 
seal, and which would of course be located on the interior of the 
mattress, can be easily removed through the valve opening 26. 
One of the unique aspects of the water bed mattress of the present 
invention is that by using the insert panel 28 within the cut-out portions 
of the sheet it is possible to form the water bed mattress without the 
excessive material which would normally gather at the corner portions of a 
rectangularly shaped mattress. Moreover, and in other constructions, some 
previous attempts to obviate this problem have relied upon the formation 
of pleats to overcome the inadvertent and otherwise uncontrolled gathering 
of the plastic material. However, the formation of pleats only controls 
the problem of gathering material, but nevertheless did create substantial 
heat sealing problems and had a tendency to result in substantial danger 
of leakage by virtue of ineffective sealing. The use of the insert panels 
is also highly unique in that it enables a water bed mattress to be 
constructed from a single sheet of unrolled plastic material and which has 
almost virtually eliminated the problem of waste of plastic sheet 
material, which is otherwise considerably high in the manufacture of water 
beds. In this respect, the insert panels 28 can actually be formed from 
the portions of the plaxtic sheet removed at the cut-outs 52. Hence, a 
complete water bed mattress can be made with one unrolled sheet of plastic 
material. 
The water bed mattress of the present invention, and one constructed by the 
method herein, is also highly advantageous in that the seamed edges are 
actually removed somewhat from the corner portions of the frame which 
holds the water bed mattress. Consequently, there is less likelihood of 
inadvertent damage to the seams, a problem which exists with respect to 
conventional water bed mattress. Thus, the water bed mattresses of the 
present invention provide a substantially increased safety factor when 
compared to such other conventional forms of water bed mattresses. One of 
the other unique advantages of the water bed mattress of the present 
invention is that they provide a substantially increased fit with respect 
to a surrounding support frame. 
While vinyl plastics are used in the formation of the water bed mattresses 
of the present invention, other forms of plastic material may be used and 
include polyethylene, polystyrene, polybutadiene copolymers and other 
resinous substances which can be made in the form of plastic sheets, but 
which nevertheless have the qualities of being foldable and flexible. 
While the materials mentioned above are thermo-plastics in nature, it 
should be understood that many thermo-setting resins could also be used. 
In addition, various flexible non-plastic materials could also be 
employed, as for example, various textile materials which are water 
impervious and which may be plastic impregnated, such as those cloth 
materials which are impregnated with a vinyl plastic material and which 
render the same water impervious. The upper and lower sheets, as well as 
the peripheral side wall, should preferably have a thickness of no less 
than 20 mils. However, the desired thickness may be predicated upon the 
overall size of the mattress itself. 
FIG. 12 illustrates an apparatus which may be used in the formtion of the 
corner portions of the mattress of the present invention. The apparatus, 
which is designated by reference numeral F, comprises a base fixture 60 
and a retaining fixture 62. In this case, the base fixture 60 includes a 
base plate 64 and an upstanding forming block 66 constituting a first die 
forming member. The forming block 66 has an outer peripheral side wall 68 
which has a shape essentially conforming to the inturned flange 30 on the 
insert panel 28. In essence, the inturned flange 30 is actually formed on 
the forming block 66 by means of the peripheral surface 68. The flat 
portion of the insert panel 28 is then located against one flat face 70 or 
flat wall of the forming block. 
The insert panel may also be retained on the forming block 66 by means of a 
magnet 72. In this case, the forming block 70 could be formed of a 
magnetic material which couples with the magnet 72 or, otherwise, an 
individual magnet 74 could be located in the flat face 70 of the forming 
block 66. The magnet 72 would hold the insert panel on the face 70 by 
means of a magnetic attraction to the forming block 70. Moreover, the 
vertically disposed portions of the inwardly struck flange 30 on the 
insert panel 28 are retained on the forming block 66 by means of a pair of 
releasable clamps 76. In this case, the clamps may adopt any form of 
conventional clamping mechanism. The clamps would also engage the portion 
of the insert panel over the peripheral side wall 68 and hold the same in 
tight-fitting retention thereon. Thus, the action of the magnet 72, along 
with the clamps 76, hold the insert panel on the forming block 66. In this 
case, the portion of the plastic sheet 40 which surrounds the cut-out 52 
is also located over the peripheral surface 68 and retained thereon in the 
same manner as the insert panel is held. 
The retaining fixture 62, which constitutes a second die forming member, is 
designed to cooperate with the base fixture 60. In this case, the 
retaining fixture 62 includes a pair of vertically disposed legs which are 
connected by a horizontally extending arm, or bight, 80. The legs 78 and 
the horizontal arm 80 are designed to create an enlarged recess designated 
by reference numeral 82, and which has a size and shape similar to the 
peripheral surface 68 of the forming block 66. In this case, it can be 
observed that the legs 78 and connecting arm 80 have an interior engaging 
surfact 84 which will engage the plastic components on the forming block 
66, as previously described. 
The legs 78 include upwardly extending sections 86 and a similar upwardly 
extending section 88 is also formed on the connecting arm 80. In this 
case, it can be observed that the connecting arm 80 is relatively thin 
compared to the overall thickness of the legs 78. Again, the upwardly 
extending sections 86 and 88 are also relatively thick compared to the 
cross-sectional thickness of the arm 80. This construction is uniquely 
designed to provide a constant RF, or other form of dielectic heat across 
the plastic component. The increased thickness of the legs 78 permit the 
same amount of dielectric energy to be applied at the lower portions of 
the peripheral surface 68, that is near the base plate 64, inasmuch as 
these portions are further removed from the source of RF, or other form of 
dielectric energy. It has been found that the extension 88 on the 
connecting arm 80 provides the proper amount of RF or other dielectric 
energy to the connecting arm 80, and the upper extensions 86 provide that 
necessary amount of dielectric energy to the legs 78 so that the entire 
face 84 presents a substantially constant amount of dielectric energy 
across the entire aperture or recess 82. 
Thus, there has been illustrated and described a unique and novel form of 
water bed mattress and the method of making the same and an apparatus used 
in the making of the same which fulfills all of the objects and advantages 
sought therefor. It should be understood that many changes, modifications, 
variations and other uses and applications will become apparent to those 
skilled in the art after considering this specification and the 
accompanying drawings. Therefore, any and all such changes, modifications, 
variations, and other uses and applications which do not depart from the 
spirit and scope of the invention are deemed to be covered by the 
invention which is limited only by the following claims.