United States Patent (19)
`Dotson
`
`11
`45
`
`Patent Number:
`Date of Patent:
`
`5,020,176
`Jun, 4, 1991
`
`4,803,744 2/1989 Peck ........................................ 5/453
`54 CONTROL SYSTEM FOR FLUID-FILLED
`4,829,66 5/1989 Walker .................................... 5/449
`BEDS
`4,838,309 6/1989 Goodwin ................................ 5/456
`4,873,737 10/1989 Savenije .................................. 5/455
`75 Inventor: Derek P. Dotson, Thousand Oaks,
`Calif.
`Primary Examiner-Gary L. Smith
`d
`Assistant Examiner-F. Saether
`73) Assignee: Angel Echevarria Co., Inc., Los
`Attorney, Agent, or Firm-Henry M. Bissell
`Angeles, Calif.
`57
`ABSTRACT
`(21) Appl. No.: 424,863
`A system for automatically controlling the pressure
`22 Filed:
`Oct. 20, 1989
`maintained in a plurality of fluid-filled cylinders sup
`51 Int. Cl........................ F16K 31/12, A47C 21/08
`porting a sleep surface in order to maintain a desired
`52 U.S. C. ........................................... 5/453; 5/455;
`degree of firmness/softness. In one mode, the system
`s
`37/8.5: 17/38
`58) Field of Search ................... 3/3, 56.95 permits the user to set the desired level of firmness and
`5/455; 137/487.5; 297/DIG. 3; 417/18, 20, 38
`then the system acts to maintain that level under the
`(56)
`References Cited
`conditions encountered in use, either venting if an
`above-setting pressure is sensed or pumping to fill if a
`U.S. PATENT DOCUMENTS
`below-setting pressure is detected. In another mode, the
`E. ty E. t 8 we w w w
`or a owe was a a was & a w is
`is : user is enabled to manually activate either the pump or
`sy
`vs.
`WenSOn . . . . . . . . . . . . . . . . . . . . . ....... . . . .
`4,435,864 3/1984 Callaway ................................
`the vent in order to vary the firmness to his choice.
`4,634,179 1/1987 Hashimoto ...
`297/DIG. 3
`4,720,807 1/1988 Ferran .............................. 137/487.5
`21 Claims, 3 Drawing Sheets
`
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`CONTROLLER
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`REMOTE
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`3O4 HERS
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`OAS
`
`Sleep Number Corp.
`EXHIBIT 2090
`IPR2019-00514
`Page 1
`
`

`

`U.S. Patent
`
`June 4, 1991
`
`Sheet 1 of 3
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`5,020,176
`
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`3O4 HERS
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`Sleep Number Corp.
`EXHIBIT 2090
`IPR2019-00514
`Page 2
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`

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`US. Patent
`
`June 4, 1991
`
`Sheet 2 of3
`
`5,020,176
`
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`Sleep Number Corp.
`EXHIBIT 2090
`|PR2019-00514
`
`Page 3
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`Sleep Number Corp.
`EXHIBIT 2090
`IPR2019-00514
`Page 3
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`U.S. Patent
`
`June 4, 1991
`
`Sheet 3 of 3
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`5,020,176
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`Sleep Number Corp.
`EXHIBIT 2090
`IPR2019-00514
`Page 4
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`

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`O
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`15
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`5,020, 176
`2
`action of the "water bag”, in that it is possible to vary
`the firmness of the sleep surface from one side of the bed
`to the other, simply by adjusting the degree to which
`the individual cylinders are filled with water.
`Most recently, advances in bed design have been
`directed to achieving the capability of adjusting the
`degree offirmness of support automatically at different
`points of the sleep surface by using a settable control,
`much like the temperature of two sides of an electric
`blanket can be individually adjusted by setting a rheo
`stat in a control system which includes sensors capable
`of monitoring temperature or some analog thereof. A
`feature such as the automatic control of the degree of
`support of the sleep surface with maintenance of the
`apparent firmness at a present level, selectable by the
`user, regardless of the load on the sleep surface, is a
`highly desirable attribute in a bed where sleep comfort
`is important to the user. It is also desirable from the
`standpoint of salability of the product, since it is a fea
`ture that provides a favorable comparison with other
`types of beds which are incapable of providing such a
`feature.
`Accordingly, it is a general object of the present
`invention to provide a system for a fluid supported bed
`which allows selection of a setting which is variable
`over a range of firmness levels. It is a further object of
`the present invention to provide such a system which
`has the capability of automatically adjusting the degree
`of support to accord to the preset firmness level as the
`load on the sleep surface changes, as when a person
`moves around on the sleep surface or gets on or off the
`bed.
`
`30
`
`1.
`
`CONTROL SYSTEM FOR FLUID-FILLED BEDS
`
`BACKGROUND OF THE INVENTION
`1. Field of the Invention
`The present invention generally relates to fluid-filled
`beds, such as water beds or inflated tube mattresses, and
`more particularly relates to an automatic control system
`for such beds.
`2. Description of the Related Art
`Beds and mattresses, sometimes referred to as sleep
`surfaces, have long been an important item of furniture
`in homes, temporary lodgings, or wherever people go
`when in need of sleep. On the average, a person spends
`about one-third (eight hours, more or less, of each
`twenty-four hour interval) of his life in bed. Clearly, the
`degree of comfort provided by one's bed is important to
`the user.
`Various factors contribute to or detract from the
`20
`comfort of a bed: the surface "terrain', whether smooth
`or lumpy; the degree of firmness; the type and unifor
`mity of support over the sleep surface; etc. An uncom
`fortable bed may interfere with sleep by keeping a per
`son from going to sleep readily or by causing the person
`to sleep fitfully during the night. Even a bed that is not
`25
`noticeably uncomfortable may still cause the user to
`awake in the morning with certain aches and pains,
`stiffness or the like as a result of an unsatisfactory sleep
`surface.
`Until the introduction of coil springs, improvements
`in the designs of beds were directed more to their
`shapes and configurations, such as their use of paneling
`with posts supporting a canopy, etc., than to the degree
`of comfort afforded the occupants. With the develop
`ment of coil springs, which were first fitted into mat
`35
`tresses in the early 19th century, bed comfort was trans
`formed. Over the next 150 years or so, beds evolved
`into the general form in common use today, generally a
`metal frame supporting a spring structure on which a
`mattress, which may also incorporate springs, a foam or
`similar support or a combination of the two, is placed.
`With 150 years of development, the current coil
`spring bed with an inner spring mattress has about
`reached the pinnacle of its design. Current innovation in
`the development of beds and mattresses involves the use
`of fluid supported sleep surfaces. The waterbed, as it
`was known, which became a minor fad about a genera
`tion ago, was in its simplest form merely a plastic sack
`or bag which was filled with water. It was noted for its
`"wave action', which contributed to new sleep sensa
`50
`tions; for its substantial weight because of the volume of
`water involved; and for its tendency to develop leaks.
`These two latter aspects gave the term "water bed' an
`unpleasant connotation, particularly with landlords
`whose rented apartments were sometimes damaged by
`55
`tenants' water beds.
`The problems with waterbeds of the single cell type
`have been largely overcome by the substitution of a
`plurality of water filled cylindrical containers as sup
`port members. These are typically arrayed side by side
`in a central cavity in the bed structure. Since each con
`tainer only holds about thirty pounds of water, they can
`be manipulated much more readily, and a leak in one
`container is not disastrous because the volume which is
`involved is much less; also, a waterproof liner in the
`65
`cavity is adequate to contain water from a leaking cylin
`der. The multi-cell configuration provides one out
`standing advantage, in addition to eliminating the wave
`
`SUMMARY OF THE INVENTION
`In brief, arrangements in accordance with the present
`invention comprise a fluid pump coupled to pressurize
`the plurality of chambers of a fluid flotation bed. Asso
`ciated with the pump is a controller which includes a
`venting device, sensors for monitoring the firmness
`level of the sleep surface as determined by the pressur
`ized cylinders, selection and display elements for inter
`facing with the user, and a special purpose computer for
`activating the pump and venting valve in response to
`sensor signals, relative to the predetermined settings of
`the selection element.
`In one particular arrangement in accordance with the
`invention which is specifically adapted for pneumatic
`operation, the pump is an air pump and the vent valve is
`arranged to vent to atmosphere. Moreover, where the
`plurality of cylinders is organized in two sets so that the
`firmness of the sleep surface may be separately deter
`mined for the two opposite sides of the bed, the cylin
`ders are connected by sets to corresponding individual
`plenum chambers, each of which is separately associ
`ated with venting and pumping means. Separate sensors
`are provided for the two independent systems and dual
`channels are incorporated in the computer to provide
`independent control of the two sets of cylinders. Alter
`natively, the sensing and control of respective pressures
`in the individual sets of cylinders may be conducted on
`a time multiplex basis with the computer being switched
`alternately between the sensors and selectors of the
`respective systems and valving being activated to con
`nect the vent and/or pump to the particular system
`calling for venting or pumping at a given time.
`In accordance with one particular aspect of the in
`vention, the controller operates on a repetitive cycle,
`
`Sleep Number Corp.
`EXHIBIT 2090
`IPR2019-00514
`Page 5
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`5,020, 176
`4.
`3
`FIG. 1 is a perspective view, partially cut away, of a
`whenever power is on, to update the display element in
`fluid flotation bed having a plurality of pressurized
`accordance with the existing condition of the cylinders
`cylinders of the type with which the present invention
`which are associated therewith and to monitor the sta
`tus of the selection element, preferably a push button
`is associated;
`FIG. 2 is a schematic diagram of one particular ar
`device having selection keys for "firm', 'soft', and
`rangement in accordance with the present invention
`"manual'. If one of the push buttons is pressed, the
`showing the cylinders of the fluid flotation bed of FIG.
`CPU logic determines which push button is activated
`1 interconnected to form a dual system;
`and controls the system accordingly. Computer men
`FIG. 3 is a schematic block diagram of a controller
`ory stores the setting which is keyed in by the user.
`and pressurizing system in accordance with the present
`When in the automatic mode, pressing the "firm' push
`invention for controlling the firmness of one of the
`button increments the pressure setting, while pressing
`cylinder sets shown in FIG. 2;
`the 'soft' push button decrements the pressure setting.
`FIG. 4 is a flow chart illustrating the method of oper
`At the beginning of each monitoring cycle, the com
`ation of the arrangement of FIG. 3;
`puter checks the bed pressure as indicated by the associ
`FIG. 5 is another flow chart illustrating the operation
`ated sensor and compares it with the preset level. If the
`of a portion of the arrangement of FIG. 3.
`pressure is above the set level by a predetermined
`threshold amount, the vent valve is opened for a prede
`DESCRIPTION OF THE PREFERRED
`termined reference interval. This interval is typically in
`EMBODIMENTS
`the range of 10 to 15 seconds for a king size bed of the
`FIG. 1 illustrates fluid flotation sleep surface 10. The
`20
`type described. A queen size bed, being somewhat
`exterior of the structure is formed as a pair of bordered
`smaller, will have a slightly shorter reference interval.
`panels or frames, the outer margins of which have sub
`Other factors, such as the size of pump and vent, may
`stantial height and register together so as to define an
`also enter into the choice of a reference interval. There
`interior cavity or enclosed volume into which the fluid
`after, the bed pressure is read again and a calculation is
`filled containers can be incorporated. The bottom panel
`25
`made to determine the difference between the bed pres
`structure comprises a base urethane foam sheet 12, to
`sure and the level setting. The computer then selects a
`the outer periphery of which is secured a border mem
`vent time interval corresponding to that calculated
`ber comprising a wedge-shaped or inclined foam wall
`difference and opens the vent valve for that interval.
`14 which is joined to the margin of the base foam sheet
`Another reading is taken and, if the pressure is still
`12 about its periphery. The area defined within the
`above the desired setting by more than the threshold
`inclined surfaces of the wedges 14 comprises a well or
`amount, further venting occurs for a recalculated inter
`open cavity under the principal sleep surface of the
`val. For example, if the pressure difference is 0.4 psi and
`mattress 10. The top panel has a centrally disposed
`the system vented 0.2 psi in fifteen seconds, a vent inter
`urethane foam layer 16 and an outer peripheral border
`val of 30 seconds (2 times 15 seconds) is selected.
`of resilient foam 18 of rectangular cross-section that is
`Similarly, if the sensed pressure is below the preset
`substantially the height of the mattress. The mattress
`level by a predetermined threshold amount, the pump is
`cover comprises a quilted top surface of polyurethane
`activated for a predetermined reference interval which
`foam and polyester ticking, the foam layer 20 being of
`may correspond to the predetermined reference inter
`substantial height so that the foam layer 20 is unified
`val for venting, but can be different if other consider
`with the ticking 22. A side quilted margin 24, which
`ations call for it. The bed pressure is again tested and a
`may be of urethane fabric, extends around the periph
`calculation of the difference is made. The computer
`ery.
`then selects a corresponding time interval and activates
`Within the interior of the enclosed volume thus de
`the pump for that interval. Pumping to a desired pres
`fined when the top panel is registered over the bottom
`sure is controlled in the same way that venting is con
`panel, there is disposed a plurality of generally cylindri
`45
`trolled, as described above. In this way, the system is
`cal containers 30 in the form of elongated sealed tubes
`controlled to approach the fluid pressure level which is
`having a nominal diameter of approximately 5' when
`preset by the user without overshoot or undesirable
`filled. For a king size sleep surface, nine of the contain
`oscillations about the preset value. Furthermore, the
`ers, or tubes, 30 are sufficient. Each tube includes a fill
`microprocessor is free to continue its cycling procedure
`opening which will be described in more detail herein
`50
`while venting or pumping is taking place for the calcu
`after. The tubes 30 are pliant and flexible, in the sense
`lated interval.
`that they conform freely to the body of an occupant of
`The "manual' key is a toggle which shifts between a
`the bed when the tube is substantially filled. The tubes
`30 can be filled or pressurized to varying degrees so as
`manual mode and an automatic mode each time it is
`pressed. When in "manual” mode, pressing the "firm'
`to comprise a range of support for the sleep surface. The
`55
`button, activates the pump which continues to pump
`support can be uniform across the area, or varied with
`fluid into the bed until the selection button is released. If
`different tubes. With a double or large size bed, to be
`the "soft' button is pressed, the vent is activated and
`used by two persons, support on each side can be tai
`will release fluid until the button is released. With each
`lored to the desires of each individual.
`successive cycle, the display is updated to the current
`Underneath the tubes 30 and disposed across the top
`pressure value, converted to an indication of relative
`of the bottom panel in the event water is the support
`firmness, as monitored by the system sensor.
`medium is a water carrier or collector sheet 36 which
`fits into the concavity defined by the top of the foam
`BRIEF DESCRIPTION OF THE DRAWING
`sheet 12 and within the inclined surfaces defined by the
`A better understanding of the present invention may
`wedges 14. It is advantageous, for cost and durability
`65
`be gained from a consideration of the following detailed
`purposes, to use tubes 30 of approximately 20 mil thick
`description, taken in conjunction with the accompany
`plastic. Other thicknesses of materials may be used as
`ing drawing in which:
`appropriate for the materials employed, the specific use
`
`60
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`30
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`35
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`Sleep Number Corp.
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`Page 6
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`10
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`5,020, 176
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`5
`the 'soft' button 76 is pressed, the vent valve 58 is
`to be made of the product and other considerations
`which may apply.
`activated to reduce pressure. In manual mode, if neither
`The preferred embodiment of the invention is dis
`button 74 or 76 is pressed, the pump and vent are turned
`off and the display setting is updated.
`closed in the context of a pneumatic bed, in which the
`During normal cycling of the microprocessor, if no
`cylinders are pressurized with air, the pump is an air
`key push setting is encountered, the microprocessor
`pump and the venting means vents to atmosphere. It
`proceeds to test the bed pressure by sensing the signal
`will be understood that this is by way of illustration and
`not limitation. The system of the invention can be uti
`from the transducer 54 which it then compares with the
`lized in accordance with liquid-filled cylinders with the
`pressure setting as determined by the remote control 62.
`addition of a storage reservoir for receiving liquid
`If the measured pressure corresponds to the setting, the
`cycle is completed. If the pressure does not correspond
`which is vented from the support system and from
`which a liquid pump draws liquid with which to pres
`to the setting, a determination is made as to whether the
`surize the cylinders. Alternatively, the system can be a
`pressure is above or below the setting. If above the
`setting, the vent valve is opened for a predetermined
`hybrid, if desired, in which a base or foundation level of
`support is afforded by a liquid medium and the differen
`reference interval: for example, 15 seconds for a large
`15
`tial pressure level is determined by pumping air into the
`bed. At the end of that interval, the pressure is checked
`cylinders or venting air to atmosphere.
`again and the microprocessor 82 calculates the differ
`ence between the pressures at the beginning and end of
`FIG. 2 shows a system 50 in accordance with the
`present invention in which six cylinders 30 are intercon
`the vent reference interval and uses this data to establish
`nected in two sets of cylinders 30A and 30B. The three
`a period that the vent valve is to remain open in order
`20
`cylinders in a set are coupled to an associated plenum
`to bring the bed pressure to the selected setting. The
`process is repeated on the next clock cycle and further
`chamber 52 to which are connected a sensor 54 and a
`pump 56. The plenum chamber 52 also connects to a
`venting is conducted if the pressure is still above the
`setting by the threshold amount. If the pressure is below
`vent 58. Like connections are made to the two sets of
`cylinders 30A and 30B, and the respective elements are
`the setting by the threshold amount, the pump is acti
`25
`designated with the letters “A” or "B" accordingly. A
`vated for a predetermined pump reference interval. Bed
`controller 60 is shown intercoupled with all sensors,
`pressure is tested again and a calculation is performed to
`pumps, and vents, as well as to a pair of remote control
`determine the difference between the pressures at the
`beginning and end of the reference interval. This data is
`units 62A, 62B.
`FIG. 3 is a schematic block diagram illustrating the
`used to determine a time interval that the pump should
`operative elements for controlling the pressure in the
`run in order to bring the pressure to the selected setting.
`The cycle is repeated until the pressure is brought
`containers 30 of FIG. 2. As indicated in FIG. 3, each
`pressure controlled system principally comprises three
`within the pressure threshold of the selected setting.
`units, a plenum 52, a pump enclosure 64 and a remote
`FIG. 5 is a flow chart indicating the operation of the
`unit 66. The pump enclosure 64 contains the pressure
`microprocessor 82 in association with the push button
`transducer or sensor 54 coupled to a converter 66 for
`set 72 of FIG. 3. The key set is scanned to determine if
`converting output voltage from the sensor 54 to a corre
`a button is pressed. If no button is pressed, the status of
`sponding frequency signal to be sent to the remote unit
`the button set 72 is set accordingly to either manual or
`automatic mode, depending upon the last setting of the
`66, a vent valve 58 and a pump 56. The remote unit 66
`contains the remote control 62 and associated controller
`'manual' button 78. If either of the 'soft' or 'firm'
`60. The remote control 62 has a display element 70 and
`buttons 74, 76 is pressed, the readout stage of the button
`set 72 is set accordingly.
`a selector device in the form of a set 72 of push buttons
`74, 76 and 78 respectively designated "firm", "soft",
`Through the use of the present invention, variations
`and "manual'. The controller 60 has a power adaptor
`in firmness/softness of the sleep surface can be con
`80, a microprocessor 82 including memory 84 and a
`trolled as easily as one controls the temperature devel
`45
`driver stage 86. The CPU receives input signals from
`oped by an electric blanket. The controller and the
`the push button set 72, and it controls the display 70 in
`selector buttons and display element are located in a
`accordance with the operation of the system. Signals
`remote hand-held unit which would typically be placed
`from the sensor 54 are also applied to the microproces
`on a night stand adjacent the bed. For a dual bed sys
`sor 82 which controls the driver 86 to open or close the
`tem, two such remote control units are provided, one
`vent valve 58 and activate the pump 56 accordingly.
`for each side of the bed. Just as with an electric blanket
`preset temperature setting, a particular level offirmness
`FIG. 4 is a flow chart illustrating the operation of the
`is preset and the system inflates the pneumatic cylinders
`controller 60 of FIG. 3. All elements are reset to default
`to that level upon energization of the system. Adjust
`conditions when power is turned on. Thereafter the
`display element 70 is updated and the key set 72 is inter
`ment is automatically made whenever changes in pres
`55
`rogated. If its state is active, the operation moves along
`sure are detected, as when a person gets into or out of
`the branch to the right to determine which of the push
`bed. In addition, if the user wishes to change the level of
`buttons is pressed. In the automatic mode (not "man
`firmness directly to a level he is comfortable with, he
`can control the system manually until the system
`ual') if one of the buttons 74 or 76 is pressed, the se
`lected pressure setting of the display is incremented or
`reaches his desired level of firmness. At this point he
`decremented, depending upon whether a firmer or
`can change back to automatic mode and adjust the
`firmness setting until neither venting nor pumping oc
`softer setting is desired. If neither of the buttons 74 or 76
`is depressed, the operation drops through to the begin
`curs. In this way the arbitrary scale or range of settings
`ning of the next cycle.
`in automatic mode can be quantitatively correlated to
`In the "manual” mode, pressing one of the buttons 74
`the user's own "feel' of bed firmness for maximum
`65
`or 76 activates the corresponding element, pump or
`comfort and user satisfaction.
`vent, to adjust the firmness to suit the user. Thus if the
`Although there have been described above specific
`"firm' button 74 is pressed, the pump 56 is activated. If
`arrangements of a control system for fluid-filled beds in
`
`30
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`IPR2019-00514
`Page 7
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`a plurality of individual fluid containers positioned in
`accordance with the invention for the purpose of illus
`side-by-side relationship within said cavity;
`trating the manner in which the invention may be used
`to advantage, it will be appreciated that the invention is
`a fluid flotation sleep surface for extending over the
`space defined by said cavity to enclose said cavity;
`not limited thereto. Accordingly all modifications, vari
`ations or equivalent arrangements which may occur to
`and
`a control system for said fluid-filled bed in accor
`those skilled in the art should be considered to be within
`dance with claim 1.
`the scope of the invention as defined in the annexed
`8. The fluid-filled bed of claim 7, further including a
`claims.
`second control system in accordance with claim 1, the
`What is claimed is:
`two control systems having separate pluralities of con
`1. A control system for a fluid-filled bed comprising:
`tainers juxtaposed side by side within said cavity and
`a plurality of containers for receiving fluid from a
`being independent of one another to provide separate
`pressurized source, said containers being arranged
`control of the firmness on opposite sides of the bed.
`to support a fluid flotation sleep surface;
`9. The bed of claim 8 wherein said fluid is air.
`means coupling said containers to a common plenum
`10. The system of claim 1 wherein the selector device
`chamber;
`includes means for selecting between automatic and
`a sensor for monitoring the pressure of fluid in said
`manual mode for the operation of said control system.
`chamber;
`11. The system of claim 10 wherein the selector de
`a pump for supplying fluid to said chamber;
`vice further includes a "firm' key to increase firmness
`a valve for venting fluid from said chamber;
`and a "soft' key to decrease firmness, and means for
`a selector device for setting a chosen level offirmness
`incrementing the preset firmness level in response to
`corresponding to pressure within said containers
`actuation of the "firm' key when the system is in the
`and chamber; and
`automatic mode.
`control means for comparing pressure signals from
`12. The system of claim 11 further including means
`said sensor with said chosen firmness setting and
`for decrementing the preset firmness level in response
`25
`selectively activating said pump and said venting
`to activation of the "soft' key when the system is in the
`valve upon detection of a difference between said
`automatic mode.
`pressure signals and said setting which exceeds a
`13. The system of claim 11 further including means
`predetermined threshold value where said thresh
`for directly energizing the pump in response to activa
`old value is greater than zero.
`tion of the "firm' key when the system is in the manual
`30
`2. The system of claim 1 wherein said control means
`mode.
`comprise means for repetitively monitoring said sensor
`14. The system of claim 11 further including means
`and said selector device.
`for directly opening the venting valve in response to
`3. The system of claim 2 wherein said control means
`activation of the "soft' key when the system is in the
`comprise means for activating the venting valve for a
`manual mode.
`35
`predetermined reference interval of time, recording the
`15. The system of claim 1 further including a display
`chamber pressures at the beginning and end of said
`element for displaying a visual indication of system
`interval, calculating a vent interval required to reduce
`Status.
`the chamber pressure to said chosen level based on the
`16. The system of claim 15 including means for acti
`pressure change measured during said reference inter
`vating said display element to provide a visual indica
`val, and activating said venting valve for said reference
`tion of preset firmness level.
`interval and subsequently activating the venting valve
`17. The system of claim 15 further including means
`for said calculated vent interval.
`for activating the display element to provide a visual
`4. The system of claim 3 wherein said control means
`indication of relative firmness corresponding to pres
`further include means for subsequently comparing
`sure of fluid in said chamber.
`45
`sensed chamber pressure with said chosen level and
`18. The method of controlling the pressure of fluid in
`repeating the measurement of pressure change during a
`a fluid-filled bed, which bed comprises a plurality of
`reference venting interval and calculation of a subse
`fluid containers coupled for communication with a
`quent vent interval if further reduction of pressure is
`common plenum chamber, a sensor for monitoring the
`required.
`pressure of fluid in said chamber, a pump for supplying
`50
`5. The system of claim 2 wherein said control means
`fluid to said chamber, a valve for venting fluid from said
`comprise means for activating the pump for a predeter
`chamber, and a selector device for setting a chosen level
`mined reference interval of time, recording the chamber
`offirmness corresponding to pressure within said con
`pressures at the beginning and end of said interval, cal
`tainers and chamber, said method comprising the steps
`culating a pump interval required to increase the cham
`of:
`55
`ber pressure to said chosen level based on the pressure
`(a) comparing the pressure in said chamber with the
`change measured during said reference interval and
`preset firmness level to determine the existence of a
`subsequently activating the pump for said calculated
`difference which exceeds a predetermined thresh
`pump interval.
`old value, said threshold value being greater than
`6. The system of claim 3 wherein said control means
`Zero;
`further include means for subsequently comparing
`(b) activating the venting valve for a predetermined
`sensed chamber pressure with said chosen level and
`reference interval of time in the event said sensed
`repeating the measurement of pressure change during a
`pressure is higher than the preset firmness level by
`reference pump interval and calculation of a subsequent
`more than said threshold value;
`pump interval if further increase of pressure is required.
`(c) noting the chamber pressures at the beginning and
`7. A fluid-filled bed comprising a plurality of panels
`end of said reference interval;
`assembled to form a base and peripheral border frame
`(d) calculating a vent interval which is required to
`defining an interior cavity for receiving and supporting
`reduce the chamber pressure to said preset firmness
`
`65
`
`Sleep Number Corp.
`EXHIBIT 2090
`IPR2019-00514
`Page 8
`
`

`

`5,020, 176
`10
`level, based on the pressure change detected during
`lower than the preset firmness level by more than
`said reference interval; and
`said threshold value;
`(e) activating the venting valve for said calculated
`(h) noting the chamber pressures at the beginning and
`vent interval.
`end of said reference interval;
`19. The method of claim 18 further including the
`(i) calculating a pump interval which is required to
`steps of again comparing the pressure in said chamber
`increase the chamber pressure to said preset firm
`with the preset firmness level and repeating steps (b),
`ness level, based on the pressure change detected
`(c), (d), and (e) in the event that the chamber pressure is
`during said reference interval; and
`still higher than the preset firmness level by more than
`(j) activating the pump for said calculated pump in
`said threshold value.
`terval.
`20. The method of claim 18 further including the
`21. The method of claim 20 further including the
`steps of:
`steps of again comparing the pressure in said chamber
`(f) comparing the pressure in said chamber with the
`with the preset firmness level and repeating steps (g),
`preset firmness level to determine the existence of a
`(h), (i) and () in the event that the chamber pressure is
`difference which exceeds a predetermined thresh
`still lower than the preset firmness level by more than
`old