U.S. patent application number 10/691821 was filed with the patent office on 2004-05-06 for air cushion control system.
Invention is credited to Graebe, William F. JR..
Application Number | 20040083550 10/691821 |
Document ID | / |
Family ID | 32179833 |
Filed Date | 2004-05-06 |
United States Patent
Application |
20040083550 |
Kind Code |
A1 |
Graebe, William F. JR. |
May 6, 2004 |
Air cushion control system
Abstract
An air cushion control system having an air chamber sensor
including an air chamber, a bottom out sensor and an overinflation
sensor, an air pump to inflate the air chamber, an air valve to
release air from the air chamber, connections for the air cushion
control system to an air cushion, and a microprocessor to control
the inflation and the release of air from the air chamber. The air
cushion control system reduces decubitus ulcers by incorporating
both an automatic adjustment system to prevent the seated
individual from bottoming-out in the air cushion and measure
immersion depth to maximize pressure reduction.
Inventors: |
Graebe, William F. JR.;
(Collinsville, IL) |
Correspondence
Address: |
JOHN W KEPLER, III
7733 FORSYTH BLVD., 12TH FLOOR
ST LOUIS
MO
63105
US
|
Family ID: |
32179833 |
Appl. No.: |
10/691821 |
Filed: |
October 23, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60421036 |
Oct 23, 2002 |
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Current U.S.
Class: |
5/654 ;
5/713 |
Current CPC
Class: |
A47C 7/021 20130101;
A47C 27/083 20130101 |
Class at
Publication: |
005/654 ;
005/713 |
International
Class: |
A47C 027/08; A47C
027/10 |
Claims
What is claimed is:
1. An air cushion control system comprising: an air chamber sensor
including an air chamber, a bottom out sensor and an overinflation
sensor; an air pump to inflate the air chamber, an air valve to
release air from the air chamber; means to connect the air cushion
control system to an air cushion; and a microprocessor to control
the inflation and the release of the air from the air chamber.
2. The air cushion control system according to claim 1, wherein a
housing contains the air pump, the air valve and the
microprocessor.
3. The air cushion control system according to claim 2, wherein the
air chamber sensor connects to the housing by air tubes or air
connects.
4. The air cushion control system according to claim 1, wherein the
microprocessor performs a timing sequence that measures a duration
that the air cushion is in a bottom-out condition without an
audible or a visible alarm being activated.
5. The air cushion control system according to claim 4, wherein the
microprocessor activates an alarm if the bottom-out condition
persists beyond a programmed time period.
6. The air cushion control system according to claim 1, wherein the
microprocessor manages a battery saver system that closes the air
valve and deactivates the air cushion control system if an
adjustment button is activated without an occupant on a seat
cushion connected to the air cushion control system.
7. The air cushion control system according to claim 1, wherein the
microprocessor controls the air pump to continue to operate for a
designated period of time after the bottom-out sensors are no
longer activated.
8. The air cushion control system according to claim 2, wherein the
housing is comprised of a lower housing and an upper housing,
wherein the lower housing is removably connected such that the
lower housing may be interchanged with a second lower housing of a
different size.
9. The air cushion control system according to claim 2, wherein the
microprocessor manages a low voltage monitoring system for
batteries that power the air cushion control system, wherein the
low voltage monitoring system will activate an alarm when a low
voltage is detected.
10. The air cushion control system according to claim 2, further
comprising a LED light system or a visual read out display.
11. The air cushion control system according to claim 10, wherein
the LED light system or the visual read out display signals a
bottom-out condition, an overinflation, or that an adjustment
process is occurring.
12. The air cushion control system according to claim 10, wherein
the microprocessor signals an alarm if the LED light system or the
visual read out display is disconnected.
13. The air cushion control system according to claim 10, wherein
the LED light system or the visual read out display is plugged into
the microprocessor.
14. The air cushion control system according to claim 10, wherein
the LED light system is connected to a lighted push button on the
housing and actuating the lighted push button turns on either an
LED light in the lighted push button or an audible alarm
system.
15. The air cushion control system according to claim 1, further
comprising an adjustment button that when activated signals the
microprocessor to open the air valve to release air until a
bottom-out condition is determined by the bottom-out sensor and
then the microprocessor closes the air valve and activates the air
pump.
16. The air cushion control system according to claim 1, further
comprising an adjustment button that when activated signals the
microprocessor to: perform a timing sequence that measures a
duration that an air cushion is in a bottom-out condition without
an audible or a visible alarm being activated; manage a battery
saver system that closes the air valve and deactivates the air
cushion control system if the adjustment button is activated
without an occupant on a seat cushion connected to the air cushion
control system; or control the air pump to continue to operate for
a short period of time after the bottom-out sensors are no longer
tripped.
17. The air cushion control system according to claim 1, further
comprising bottom-out sensors that when activated signal the
microprocessor to: perform a timing sequence that measures a
duration that an air cushion is in a bottom-out condition without
an audible or a visible alarm being activated; manage a battery
saver system that closes the air valve and deactivates the air
cushion control system if the adjustment button is activated
without an occupant on a seat cushion connected to the air cushion
control system; or control the air pump to continue to operate for
a short period of time after the bottom-out sensors are no longer
tripped.
18. The air cushion control system according to claim 1, wherein
the microprocessor closes the air valve of the air cushion control
system after a programmed time delay if an adjustment process is
activated without an occupant on a seat cushion connected to the
air cushion control system.
19. The air cushion control system according to claim 1, wherein
the microprocessor closes the air valve of the air cushion control
system after a programmed time delay if an adjustment process is
activated by increased temperature, pressure, or altitude.
20. The air cushion control system according to claim 2, wherein
the housing comprises: a bottom housing layer, a middle housing
layer, and a top housing layer; and wherein the top housing layer
is molded and comprises chases or vias for directing wiring and
tubing.
21. The air cushion control system according to claim 20, wherein
the middle housing layer is thinner than the bottom housing layer
and the top housing layer.
22. The air cushion control system according to claim 1, wherein
the air cushion control system will automatically recognize an
occupant by an air pressure activated switch.
23. The air cushion control system according to claim 1, wherein
the air cushion control system will automatically recognize an
occupant by an externally mounted strip sensor or a mechanical
switch.
24. An air cushion control system comprising: an air chamber sensor
including an air chamber, a bottom out sensor and an overinflation
sensor; an air pump to inflate the air chamber, an air valve to
release air from the air chamber; means to connect the air cushion
control system to an air cushion; wherein the air chamber sensor
includes an air chamber formed by sealing together two layers of a
material; wherein channel walls in the air chamber separate the air
chamber into multiple air channels; and wherein the distance from
an edge of the air chamber sensor to an end of the channel wall
does not exceed one half of the distance between the channel
walls.
25. The air cushion control system according to claim 24, wherein
the end of the channel walls does not extend totally to the edge of
the air chamber.
26. The air cushion control system according to claim 24, wherein a
top layer of material is sealed to the first two layers; wherein a
pocket layer is attached to the top layer and is capable of holding
a sensor board.
27. The air cushion control system according to claim 24, wherein
the air chamber sensor has perimeter air connects.
28. An air cushion control system comprising: an air chamber sensor
including an air chamber, a bottom out sensor and an overinflation
sensor; an air pump to inflate the air chamber, an air valve to
release air from the air chamber; means to connect the air cushion
control system to an air cushion; wherein the air chamber sensor
includes an air chamber with multiple air channel, and the air
channels contain support strips.
29. The air cushion control to claim 28, wherein the support strips
are a foam material, a plastic material, or a combination
thereof.
30. The air cushion control system according to claim 28, wherein
the support strips reduce the bleeding of air from the chamber
sensor into the air cushion.
31. The air cushion control system according to claim 28, wherein
strips are incorporated under two opposite sides of the air chamber
sensor to reduce bleeding of air from the air chamber sensor into
the air cushion.
Description
[0001] This application claims the benefit of U.S. Provisional
Patent Application No. 60/421,036, filed Oct. 23, 2002.
FIELD OF THE INVENTION
[0002] The present invention relates to an air cushion control
system. The system automatically adjusts inflation and immersion
levels for a person using an air cushion to reduce the occurrence
of decubitus ulcers.
BACKGROUND OF THE INVENTION
[0003] Individuals who are wheelchair dependent generally need
special cushioning to help prevent the formation of decubitus
ulcers, which are often commonly referred to as pressure sores or
bedsores. These individuals are often paralyzed and have lost
sensation or have impaired sensation in their lower extremities.
This loss or impairment of sensation presents problems associated
with both bottoming-out in and the adjustment level of the cushion
that the individual is sitting on. Bottoming-out raises the peak
pressures on the skin in the bottomed-out areas of the individual
to levels such that the blood flow in the capillary bed in the
bottomed-out areas will be stopped (occluded) or reduced, which
prevents vital nutrition from reaching the cells. This may cause
necrosis or cell death and result in the onset of a decubitus
ulcer. Improper adjustment or immersion can also result in
decubitus formation.
[0004] Many variations of cushioning exist, including foam, gel,
water-filled, air, foam and gel combinations, and air and foam
combinations, etc. Cushioning to aid with pressure reduction must
generally be adjusted to provide the proper fit for the shape of
the user to distribute weight load on the skin to reduce pressures.
These adjustments may involve sculpturing the foam to fit the
contours of the person's body or adding special gel bags to a gel
filled cushion. Air cushions generally require the checking of
immersion depth by inserting one's hand under the buttocks. These
adjustments may also include the checking of pressures with
expensive computerized equipment. These adjustments are often
specific and customized to the individual resulting in increased
costs. Moreover, in nearly every instance where an individual
shifts or adjust their seating posture, a new adjustment to the
cushion may be required.
[0005] Conventional cushions have many disadvantages. Cushions may
ultimately go out of adjustment or may deteriorate. Repeated use of
a foam cushion may break down the cell structure of a foam cushion.
Cushions may leak air or gel. Gel may become dry or become firm
with the passage of time. Cushions may further change adjustment
due to temperature or altitude changes.
[0006] If an individual lacks or has impaired sensation, they
generally cannot detect that their cushion has failed to support
their body properly. The individual may not be aware that a problem
exists, until such time that a decubitus ulcer may have already
formed. Even if aware of the fact that their cushion is bottomed
out, misadjusted or has failed, many individuals cannot adjust
their cushion by themselves due to their physical handicaps.
SUMMARY OF THE INVENTION
[0007] The ultimate goal of a seating system for reducing decubitus
ulcers is to contact as much skin surface area of the seated
individual as possible to provide weight distribution to lower
pressures on the skin. This may be accomplished by immersing the
individual in a cushion by releasing air from the cushion without
bottoming out. The present invention accomplishes this goal.
[0008] The air cushion control system of the present invention
generally: a housing that contains the electrical controls and an
air chamber sensor surrounded by bottom out sensors and
overinflation sensors. The air cushion control system is connected
to the air cushion to be controlled. The present invention provides
an air cushion control system for reducing decubitus ulcers by
incorporating means for both an automatic adjustment system to
prevent the seated individual from bottoming-out in the air cushion
control system and a means to measure immersion depth to maximize
pressure reduction. The air cushion control system incorporates
alarms that alert the seated individual or caregivers to seat
cushion problems, which could cause serious skin problems.
[0009] It is an aspect of the present invention to provide an air
cushion control system that automatically adjusts immersion depth
of the individual into the air cushion based upon the specific
weights, sizes and shapes of any individual.
[0010] It is an aspect of the present invention to provide an air
cushion control system that automatically adjusts to the different
seating positions and movements of the seated individual and keep
them properly immersed without bottoming out.
[0011] It is another aspect of the present invention to provide an
air cushion control system that reduces the bleed-out of air from
the air chamber sensor into the air cushion to enhance battery
life.
[0012] It is another aspect of the present invention to provide an
air cushion control system that may be used with wheelchairs, beds,
and the seating of cars, trucks, and airplanes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The present invention is illustrated by the embodiments
shown in the drawings in which:
[0014] FIG. 1 is a perspective view of an air cushion control
system and illustrates an air cushion and a housing;
[0015] FIG. 2 is a perspective view of the housing and an air
chamber sensor thereon;
[0016] FIG. 3 is a view of the bottom of a sensor board after being
removed from a pocket of the air chamber sensor;
[0017] FIG. 4 is a view of a top surface of the housing;
[0018] FIG. 5 is a perspective view of the air cushion;
[0019] FIG. 6 is a perspective view of the bottom of the air
cushion;
[0020] FIG. 7 is a view of the bottom of the air cushion;
[0021] FIG. 8 is a perspective view of the inside of the
housing;
[0022] FIG. 9 is a view of the air cushion, the air chamber sensor
with inserts, and the housing;
[0023] FIG. 10 is a view of the operation of the air cushion
control system of the present invention wherein the air chamber
sensor has the inserts therein;
[0024] FIG. 11 is a perspective view of an embodiment of the
present invention providing a low height housing with a curved
bottom for sling chair;
[0025] FIG. 12 is a exploded view of the low height housing
embodiment;
[0026] FIG. 13 is a view of an air chamber sensor having perimeter
air connects; and
[0027] FIG. 14 is a view of an embodiment with a reduced top
cover.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0028] The air cushion control system of the present invention
generally comprises: a housing and an air chamber sensor, a bottom
out sensor, an overinflation sensor and an electronic control
system. The housing is generally a firm structure that contains an
air pump, an air valve, batteries, a microprocessor and other
components. The air chamber sensor generally rests on top of the
housing and is connected to the housing by air tubes and air
connects. Under the air sensor, are both bottom out sensors and a
reed switch that controls overinflation. The air cushion control
system is connected to the air cushion to be controlled. The air
cushion generally rests on top of the air chamber sensor and is
connected to the housing by air tubes and air connects. Thus, the
air chamber sensor is generally between the housing and the air
cushion.
[0029] The air cushion control system of the present invention
provides the user a seating cushion surface that automatically
adjusts to the user's individual weight and specific contours. The
system may also be used serially by different individuals with
different shapes and of different sizes and still provide an
automatically adjusted seating surface.
[0030] The air cushion control system of the present invention may
be used with many commercially available air cushions. Air cushions
come in many different sizes but are typically about sixteen inches
by eighteen inches in size and contain many individual air
cells.
[0031] The system also re-adjusts the seating surface when the user
bottoms-out from a shift in seating position by the user. For
example, the user may cross their legs changing the support
resulting in a bottom-out. The system will recognize these shifts
in seating position if they result in a bottom-out of the user and
will subsequently readjust the seating surface to reduce or stop
the bottom-out. If overinflation results from various position
changes, the system will remove air to maintain the user deeply
immersed in the air cushion.
[0032] The adjustment is controlled by a microprocessor that may be
activated by pressing an adjustment button or by simply sitting on
the air cushion attached to the air cushion control system of the
present invention. When an individual sits on the air cushion and
bottoms-out, bottom-out sensors are activated and initiate the air
pump. The bottom-out sensors and the air pump are operationally
connected to the microprocessor. The air pump provides air to the
air chamber sensor, which is in communication with the air cushion
via air tubes and air connects. Thus, as the air enters the air
chamber sensor, it also enters the air cushion and raises the
individual off the bottom-out sensors. As the air sensor chamber
expands in height, the user seated in the cushion is raised an
equal amount.
[0033] To assure the lowest immersion depth in the air cushion, the
sitting individual may press the adjustment button. Upon pressing
the adjustment button, an audible alarm will sound momentarily to
assure the user that they have properly activated the adjustment
system. This then initiates a series of events. First, an
electrically activated air valve is opened. The air valve is
operationally connected to the microprocessor. Secondly, three
timing sequences may be initiated. The first timing sequence in the
microprocessor measures how long the user can be bottomed-out
before an alarm will sound. The first timing sequence may be user
adjustable by means of a dip-switch located on a circuit board of
the microprocessor. The second timing sequence is part of a battery
saver system that automatically measures how much time will be
allowed before the adjustment sequence is completed. The third
timing sequence allows the air pump to continue to operate for a
defined period of time after the individual is raised off the
bottom-out sensors.
[0034] Upon opening of the air valve, air is released from both the
air cushion and the air chamber sensor, allowing the individual to
be immersed into the air cushion. However, if the individual is
immersed too deeply in the air cushion, they will bottom out. To
reduce and control the bottoming-out, a sensor board may be
contained in a pocket of the air chamber sensor that has strips
that will push through the air chamber sensor to contact the
bottom-out sensors located on top of the housing, i.e., under the
air chamber sensor. The strips of the sensor board may be made to
different thicknesses to control the immersion depth of the
individual seated on the cushion. In other embodiments, the air
chamber sensor may have strips incorporated internally into it or
onto it to activate the bottom-out sensors and achieve the proper
cushion adjustment.
[0035] In a preferred embodiment, the bottom-out sensors comprise
pressure strip sensors attached on or integral to the top of the
housing. When the pressure strip sensors are contacted, the air
valve is closed and the air pump is now activated. The air pump
will continue to operate until the sensor board is no longer in
contact with the pressure strip sensors. When the pump discontinues
operation, an immersion depth for the individual is determined.
[0036] The air cushion control system also utilizes an
overinflation system that recognizes when an occupant is adjusted
to a point that they are sitting too high (i.e., not immersed
properly into the air cushion). Sitting on an over-inflated seat
cushion is similar to bottoming-out, since it prevents immersion
and raises peak pressures and may cause a decubitus ulcer. Sitting
on an over-inflated seat cushion also reduces the stability of the
individual and should be avoided. The overinflation system is
controlled via a magnetically activated reed switch and a magnet.
The reed switch may be contained in the housing and positioned
under the air sensor chamber and is operationally connected to the
microprocessor. The magnet is preferably attached to the sensor
board, which may be located in a pocket on the top surface of the
air chamber sensor. In other embodiments, the magnet is attached or
integral to the top surface of the air chamber sensor.
[0037] The magnet should have sufficient strength to hold the reed
switch open while the magnet is within a certain proximity of the
reed switch. When the air chamber sensor has risen to a distance
that is outside of the range of the magnet's strength, the reed
switch will close and complete the circuit and open the air valve.
The air is then released from the air cushion and the air chamber
sensor until the sensor board and magnet contacts the bottom-out
sensors, opening the reed switch, closing the air valve and
activating the air pump. Once the reed switch is opened, it is
temporarily removed from the system by the microprocessor until the
bottom-out sensors are activated, which re-engages the reed switch
and its magnetic control.
[0038] The first timing sequence described above measures out how
long the strips of the sensor board remain in contact with the
bottom-out sensors without an audible or visible alarm being
activated. The time may range from about zero seconds, which is
mainly used for a testing mode or the LED mode, up to about 30
seconds in ten second increments. These time sequences can be
changed by dip switch or reprogramming the microprocessor. If the
strips of the sensor board have not been raised sufficiently to not
be in contact with the pressure sensor strips in the measured
period of time, an alarm will sound. This alarm would normally
indicate that the adjustment is either not finished or that an air
leak has occurred in the system and that the user of the device or
a caregiver should respond by checking the system for air leaks or
other problems. Small air leaks may set up a cycling that will set
off the alarm. As the air leaks may grow in size, the pump cannot
override the leaks causing the alarm to begin to activate on a
cyclical basis or provide a steady alarm sound.
[0039] The second timing sequence described above is a battery
saver system designed to monitor the air valve. If during handling,
transferring from the chair, or storage, the adjustment button is
activated without an occupant on the seat cushion, the timing
system will close the air valve and deactivate the system.
Otherwise, the air valve would remain open and would drain the
batteries. However, if the unit is stored in an automobile trunk or
other area that would prevent the alarm from being heard, the user
upon retrieving it from the storage area, would possibly find that
the system is totally inoperative due to battery drain.
[0040] The battery saver system may also assist in preventing
battery drain caused by environmental conditions. If the system is
not occupied, the air chamber sensor may increase in the volume of
air raising the internal air pressure due to heat or altitude.
These fluctuations may activate the air valve and drain air out of
the system. However, without an occupant, the bottom-out sensors
will not activate. It is necessary to activate the bottom-out
sensors to close the air valve. Thus, it is preferred that after a
measured period of time, the system will automatically close the
air valve to preserve battery life.
[0041] A third timing sequence may also be initiated to allow the
pump to continue to run for a short period of time after the
bottom-out sensors are no longer tripped by the strips of the
sensor board. This allows the air pump time to add a short amount
of extra inflation to help assure that the strips of the sensor
board are no longer touching the bottom-out sensors. This minimizes
the contact between the strips and bottom-out sensors and reduces
the use of the air pump thereby conserving battery power.
[0042] The bottom-out sensors may be activated by changes in the
sitting position of the individual. The bottom-out sensors will
automatically activate the air pump and make an adjustment to
accommodate different sitting positions. All of the timing
sequences mentioned above are also activated. The timing sequences
keep the audible alarm system quiet unless a problem should
occur.
[0043] Turning now to some of the other features that may be
incorporated into the air cushion control system of the present
invention:
[0044] In some embodiments of the present invention, an alarm is
used to indicate that an overinflation condition has occurred and
has not been corrected. The microprocessor may be programmed to
sound an alarm if the bottom-out sensors are not contacted after
10, 20, or 30 seconds or other user programmed time period from the
closing of the reed switch. The alarm will provide a signal by a
pulsating audible or visual signal different from the bottom out
alarm that an overinflation condition is persisting.
[0045] The air cushion control system of the present invention may
also be activated by an air pressure activated switch connected to
the air chamber sensor and/or the air cushion. The air pressure
activated switch provides for automatic recognition of an
individual on the seating surface and automatically initiates the
adjustment. While the air cushion control system is vacant (no
occupant) the air pressure within the air chamber sensor and
attached cushion is very low. When an individual sits upon the
system, the air pressure is increased due to the occupant's weight.
This increase in air pressure will be recognized by the air
pressure activated switch operationally connected to the
microprocessor, which will then activate the adjustment procedure
described above, which may be activated manually by the adjustment
button in other embodiments. Thus, the air cushion control system
recognizes and automatically accommodates a sitting individual. The
air pressure activated switch is deactivated after the initial
weight or occupant is registered and is only reactivated when
weight is released, when the individual is no longer sitting on the
air cushion control system. This allows for recognition that an
adjustment is no longer needed as the occupant has left.
[0046] The air cushion control system of the present invention may
also be activated by a pressure strip sensor or other switching
means mounted on the bottom of the housing, or other suitable
location. Upon sitting on the system, the pressure strip sensor is
activated by the weight of the sitting individual. This activation
then starts the same adjustment procedure as described above.
However, the strip sensor is deactivated after the initial weight
is registered and is only reactivated when weight is released,
e.g., when the individual is no longer sitting on the air cushion
control system. This allows for recognition that an adjustment is
no longer needed as the occupant has left.
[0047] An optional LED light system or a visual read out display
indicating the adjustment process or condition may be incorporated
into the system. The LED will provide silent operation and will
operate in place of the audible alarm. The LED light visual read
out system will provide a steady light/read out or an alternating
light/read out to alert the user or caregiver of problems. When the
LED/read out system is plugged into the circuit board, it
automatically disconnects the audible alarm. When LED/read out
system is unplugged, it automatically reactivates the audible
alarm. The LED system can be operationally connected to a lighted
push-button on the front of the housing. Pushing the lighted
push-button will activate the system. The lighted push-button would
flash the same codes as the audible alarm system. The LED/read out
light could also be plugged into a socket mounted on the side of
the housing. Optionally, the LED/read out light could be mounted on
the arm of the wheelchair. If the LED/read out light is
accidentally disconnected, the audible alarm would be immediately
reactivated. The visual readout display would also flash and
display a written message indicating the condition, i.e., bottom
out.
[0048] An audible alarm (short beep) may be incorporated that will
sound when the batteries have been installed properly. If the
batteries are installed incorrectly, the alarm will not sound and
the system will not operate. This is provided as a protection
system so the user will install the batteries in the proper
polarity. However, if the batteries are installed in a reverse
polarity, a protection system is built into the circuit board that
will prevent damage to the circuit board and system.
[0049] Individuals using this system often have no sensation in the
lower extremities and do not sense that their cushion is not
operating properly. Also with the time delays involved they would
not normally hear or see any type of alarm. Therefore, a low
voltage monitoring system may be incorporated as part of the
electronics of the system. The monitoring system is designed to
detect low voltage when the batteries have dropped to a low voltage
level. At this point, the system is still operative and will remain
so for some time. However, an audible alarm will activate and will
continue to operate every 8 to 10 seconds providing a pulsating
sound until the batteries have been replaced. It is important that
only new batteries should be used to replace the batteries in the
system. To prevent the use of incorrect batteries, batteries that
are not of sufficient voltage to arrive at the required voltage
level, the alarm will be activated and cannot be turned off until
the batteries have been replaced with those of sufficient voltage.
The alarm sequence will be either audible or an LED/read out light
depending on the selection of the occupant.
[0050] The air cushion control system of the present invention and
embodiments thereof will now be described with reference to the
drawings:
[0051] With particular reference to FIGS. 1-4, the air cushion
control system of the present invention generally comprises: a
housing 30 and an air chamber sensor 20, a bottom out sensor 33, an
overinflation sensor 25, and a microprocessor control system 50.
The air cushion control system is connected to an air cushion 10 to
be controlled. The air chamber sensor 20 generally rests on top of
the housing 30 and is connected to the housing 30 by air tubes 12
and air connects 36.
[0052] The bottom out sensors 33 and a reed switch 25 are located
below the air sensor chamber. The air cushion 10 generally rests on
top of the air chamber sensor 20 and is connected to the housing 30
by air tubes 12 and air connects 36. Thus, the air chamber sensor
20 is generally between the housing 30 and the air cushion 10. The
housing 30 may have hatches or doors providing access to the
internal features of the housing 30 for changing the batteries or
performance or other adjustments. These hatches or doors may be on
the bottom side of the housing 30.
[0053] Turning now to FIG. 8, the housing 30 is generally a solid
supportive structure that contains an air pump 60, a solenoid air
valve 62, batteries 68, a microprocessor 50, an alarm 52, a reed
switch 64, strip sensors, and other components. The housing 30 is
comprised of a lower housing 32 and an upper housing 31. The
microprocessor 50 may comprise any of a variety of microchips
and/or circuits and/or other components well known to one of
ordinary skill in the art and needed to perform the sequences and
control the events herein described.
[0054] Turning now to FIGS. 5-7, the air chamber sensor 20 may
comprise four layers. As shown in FIG. 5, a bottom layer 76 and a
middle layer 74 are sealed together at points to form internal
seals of ribs or spacers shown as channel walls 26 that control the
inflation level of the air chamber sensor 20 and its stability. The
channel walls 26 define air channels 23. The channel walls 26
extend a substantial portion of the distance between the edges of
the air chamber sensor 20. The spacing of these channel walls 26
limit the height level of inflation within the air chamber sensor
20 and provide stability and help to govern air flow and regulate
air flow to the air cushion 10 and reactive timing for adjustment.
With particular reference to FIG. 7, the distance or spacing at the
ends of the channel walls 27 to the edge of the air chamber sensor
29 (shown as "y") must be no more than about one half the distance
between the ends of the channel walls 27 (shown as "x"). Explained
another way, the combined distance between the edge of the air
chamber sensor 29 and end of channels walls 27 for each side of the
channel walls 27 will be about equal to the distance that the
channel walls are apart from each other (2y=x). The excess material
from the sealing of the layers at the edge of the air chamber
sensor 29 as shown in the figures is preferably trimmed.
[0055] A top layer 72, i.e., a third layer of material, may be
sealed to the bottom layer 76 and the middle layer 74. The top
layer 72 may be provided with a hole 78 to prevent any leakage from
being contained by the top layer causing excessive expansion.
[0056] In order to accommodate the sensor board, a fourth layer of
material may be sealed to the top layer 72 to form a pocket 24 to
hold and position a sensor board 28. As shown in FIG. 3, the bottom
of the sensor board 28 has strips 22 and a magnet 25 affixed or
attached thereto. The strips 22 contact pressure strip sensors 33
on top of the housing 30. The magnet 25 controls the reed switch
64, which controls overinflation. In FIG. 3, the sensor board is
shown inverted.
[0057] Turning now to FIG. 4, the pressure strip sensors 33 are
shown on top of the housing 30. These pressure strip sensors 33 are
located either from side to side or front to back of the housing 30
under the air chamber sensor 20. Pushing anywhere along the length
of the pressure strip sensors 33 will close a circuit connected to
the microprocessor 50. When the pressure strip sensors 33 are
contacted, they indicate a low immersion depth of the individual
and/or bottoming-out of the air cushion. Although three pressure
strip sensors 33 are shown, any number of pressure strip sensors
may be used with the present invention.
[0058] The air chamber sensor 20 requires air connects 36 for air
to enter the air chamber sensor 20 and for air to exit the air
chamber sensor 20. The air chamber sensor 20 is preferably
constructed with three or more air connects 36. An air connect 36
is provided for each of the air pump 60, the air valve 62, and for
the air entering and exiting from the air cushion 10. In some
embodiments, the air connects are provided on the sides of the air
chamber sensor 20.
[0059] The air pressure that is within the air chamber sensor 20 is
very low. When an occupant is not sitting on the system, the
pressures within the air cushion 10 and within the air chamber
sensor 20 are extremely low. Thus, when sitting idle, the weight of
the air cushion 10 will override the air pressure in the air
chamber sensor 20. The air in the air chamber sensor 20 will bleed
back into the air cushion 10. So when an individual sits down on
the system, they will bottom out, activate the pressure strip
sensors 33, and activate the air pump 60 for a short period of
time. As soon as the pressure strip sensors 33 are activated, they
override the need to push the adjustment button 34. This can be
confusing to a user.
[0060] However, as shown in FIGS. 9 and 10, by inserting support
strips 80 of a foam or plastic cushioning material in the air
channels 23 of the air chamber sensor 20, the bleeding of air into
the air cushion 10 from the air chamber sensor 20 may be reduced or
prevented. The support strips 80 would be of a proper height and a
proper width to achieve proper actuation of the bottom out sensors
and adjustment in either a compressed or non-compressed state. The
density of the material used in support strips 80 should be such
that it will just balance out the weight of the air cushion 10 and
prevent the bleeding of the air from the air chamber sensor 20 back
into the air cushion 10 while unoccupied. The support strips 80
help the air chamber sensor 20 to remain in the previous adjustment
for the user and thus reducing the activation of the air pump 60.
This will be an advantage to the user and will also help to improve
battery life. In FIG. 9, the air chamber sensor 20 is shown
inverted. In other embodiments, bleed out may be reduced by the
incorporation of strips, such as, for example, foam strips of
approximately 1/2 inch, under the air chamber sensor 20 along the
left and right exterior edges. These strips help support the air
chamber sensor 20.
[0061] In some embodiments of the present invention, the air
chamber sensor 20 may also have plastic strips 82 or strips of
another hard material inserted into the air channels or attached to
the bottom of the air chamber sensor to replace the strips 22 on
the sensor board 28. The thickness of the plastic strips 82 and, if
combined with foam (when compressed), help determine the depth of
immersion. The strips are preferably perpendicular to the pressure
strip sensors 33 or other bottom-out sensor.
[0062] In some embodiments of the present invention, the air
chamber sensor 20 may also have plastic strips 82 matted to the
support strips 80 or placed inside of the support strips 80. These
plastic strips along with the foam may replace the strips 22 on the
sensor board 28, as well as balance out the air in the air chamber
sensor 20 versus the weight of the air cushion 10 to prevent and
reduce bleeding of the air back into the air cushion 10.
[0063] The air chamber sensor 20 serves as a sensor control system
that determines the immersion depth of an individual sitting on an
air cushion. The sensor control system comprises two sensors. One
sensor determines the lower level of immersion, e.g., the pressure
strip sensors 33, while the second sensor, e.g., the magnetic reed
switch 64, determines the upper level of immersion of the
individual sitting on the air cushion.
[0064] The air chamber sensor 20 may be any shape that supports an
air cushion. However, as shown in FIGS. 5-7, the air chamber sensor
20 is preferably a rectangular shape and is constructed using 4
layers of a material, such as flexible thin vinyl, coated
polyurethane, coated nylon, rubber or other similar and flexible
material. In other embodiments of the present invention, an air
chamber sensor 20 is formed from two layers of material.
[0065] With continued reference to FIGS. 5-7, the first two layers
of the air chamber sensor, bottom layer 76 and middle layer 74,
form the core of the sensor system. These two layers may be sealed
together with RF energy, adhesives, or other conventional sealing
techniques. The first two layers contain channel walls 26 that run
from one side of the air chamber sensor 20 to the other and form
air channels 23. The distance between the channel walls 26 forms
air channels 23. The distance between the channel walls 26 controls
the maximum height the air chamber sensor 20 may be inflated. The
end of the channel walls 27 cannot extend totally to the edge of
the air cushion 29. A space must remain at the end of the air
channels 23 to allow air to move freely from one air channel 23 to
another. However, the distance from the edge of the air chamber
sensor 20 to the end of the channel wall 27 should not exceed one
half (1/2) of the distance between the channel walls 26. This
provides for uniform support and expansion of the air sensor
chamber 20. This uniform support and expansion is important to
provide proper adjustment for the individual sitting on the air
cushion. Without uniform support and expansion of the air sensor
chamber 20, the proper lift nesecary to achieve proper adjustment
is not achieved.
[0066] With continued reference to FIGS. 5-7, a top layer 72 of
material is sealed to the first two layers. Attached to top layer
72 is a pocket 24 that holds the sensor board. This sensor board 28
also holds and keeps in place a magnet that controls the actions of
the magnetic reed switch that is located under the air chamber
sensor.
[0067] The system of the present invention is a very dynamic
responsive system. It has no "on" or "off" control, as the system
is always in a "ready" position. The system only activates itself
when needed as a response to either a high or low sitting
situation. The pressure strip sensors 33, which direct
bottoming-out, are always active and are not turned off. When an
individual positions themselves on the system, it will
automatically react. If the individual sits too low and bottoms
out, the system will activate and adjust. If they are sitting too
high, it will activate and adjust. If no action is taken, the
individual can initiate adjustment by pushing the adjustment button
34. This will assure the lowest sitting position. The amount of
pressure on the bottom-out sensor needed to activate the bottom-out
sensor may be regulated by adjusting the width of the bottom-out
strip sensors. Preferably, the pressure needed to activate the
bottom-out sensor 33 is about six pounds.
[0068] The electronics that control the system operate as follows.
To activate the system, the user either sits on the system or
pushes an adjustment button 34. Upon successfully pushing the
adjustment button 34, an audible alert will sound to provide
feedback to the person that the adjustment procedure has been
properly activated. This alert is always audible, even with an LED
system in operation. At this point the electrically operated air
valve 62 opens. This allows air in the air chamber sensor 20 to
evacuate as well as air in the attached air cushion 10 to evacuate.
As the air is removed, the sensor board 28 attached to the top of
the air chamber sensor 20 immerses itself into the air chamber
sensor 20. When the strips 22 attached to the sensor board 28 push
themselves through to the pressure strip sensors 33, they close the
circuit. This closes the air valve 62 and starts the operation of
the air pump 60. At this time, three simultaneous timing sequences
in the microprocessor 50 may begin. These timing sequences begin
anytime the bottom-out sensors are contacted, whether the
activation was begun by pushing the adjustment button 34 or not. In
some embodiments, rechargeable dry lead/acid batteries may be used
for powering the present invention.
[0069] The first timing sequence activates an alarm 52 that
indicates that the system is in a bottomed-out situation. The
volume of the alarm may be adjusted from a high setting to a low
setting. The alarm may 52 have one or more time delayed settings,
controlled by a series of dip-switches, and controlled by the
microprocessor 50. Preferably, the alarm 52 has four time delayed
settings. The first setting may be a "0" time delay and activates
an alarm 52 immediately upon contacting the pressure strip sensors
33, i.e, bottoming-out. The "0" delay may be a testing position or
a LED/read out setting. The other three time delay settings extend
the time up to 30 seconds before the alarm activates after
contacting the pressure strip sensors 33. This time setting, for
example, may be changed by the programming of the microprocessor
50.
[0070] The bottom-out alarm is a continuous alarm that will not
stop until the pressure strip sensors 33 are no longer being
contacted. This is an important feature of the present invention as
an individual who is bottomed-out may develop decubitus ulcers.
[0071] A second timing sequence extends the operation of the air
pump 60 for a short duration of time after the pressure strip
sensors 33 are no longer being contacted. This serves to lift the
strips 22 located on the sensor board 28 slightly off the pressure
strip sensors 33.
[0072] A third timing sequence is also initiated by pushing the
adjustment button 34. This timing sequence times out the operation
of the system from the time the adjustment button is pushed until
the time the pressure sensor strips 33 are contacted. This is
important since during transportation or storage of the system, the
adjustment button 34 may be accidentally activated, i.e., by
storing the system in a car trunk, etc. If the air valve 62 is
opened accidentally, it will remain open until the pressure strip
sensors 33 are contacted. If the system is being stored overnight,
for example, and is not in use, the air valve 62 will remain open
and drain the batteries 68 making the system inoperative. After the
third timing sequence of approximately two minutes which can be
changed by programming and the pressure strips sensors 33 are not
activated, the microprocessor 50 will close the air valve and shut
down the system until it is reactivated by pushing the adjustment
button 34 or by applying pressure to the pressure strips sensors
33.
[0073] The present invention provides many advantages. If a person
changes their sitting position by leaning to one side or another,
moving forward on the air cushion, or even lifting and crossing a
leg, a bottom-out or over-inflation situation may occur. If a
bottom-out situation occurs, the air pump 60 may activate to add
air to the system until the bottom-out condition has been
corrected. If the individual then returns to a more upright
position, then the system may have too much air and will be in an
overinflation mode resulting in a release of air through the air
valve 62.
[0074] Other advantages of the present invention include means to
close the air valve 62 if it is unintentionally opened. If the air
in the air chamber sensor should increase in pressure while sitting
in storage, etc., the reed switch 64 will activate the opening of
the air valve 62. The air valve 62 will only be closed after the
air has evacuated sufficiently to allow contact with the pressure
strip sensors 33. If no one is sitting on the unit, there will not
be sufficient pressure exerted on the pressure strip sensors 33 to
complete the circuit and close the air valve 62. The air valve 62
will remain open and drain the batteries 68 of their power. To save
battery power, the air valve 62, if not closed in a preset time
period of approximately 2 minutes, will be closed by the
microprocessor 50. The system may be reactivated by pressing the
adjustment button 34 or pressing the pressure strip sensors 33.
After the air valve 62 is closed, the audible alarm will come on.
The audible alarm is a pulsating alarm that indicates
overinflation.
[0075] In some situations, the user of the system may not want an
audible alarm to activate. In this case, the audible alarm can be
turned off and replaced with a LED/visual read out light alarm. The
LED light alarm may be incorporated into the present invention in
several ways. The first version uses a lighted push-button 37
mounted on the front of the plastic housing. Pushing the button in
will result in the LED located inside the push-button to flash the
alarm. Pushing the button again will reactivate the audible
alarm.
[0076] In certain embodiments, as shown in FIG. 11, a socket 104 is
mounted on the side of the housing 30. An LED/visual read out light
assembly can be quickly mounted on the arm of the wheelchair and
can be plugged into the socket. As soon as this unit is plugged
into the socket, the audible alarm is automatically disconnected.
If accidentally unplugged, the audible alarm system will be
automatically reactivated.
[0077] In another embodiment of the present invention, as shown in
FIGS. 11-13, a low height housing structure 90 is shown with an air
chamber sensor 20 having perimeter air connects 102. This
embodiment provides a thinner air cushion control system, which may
be easier for an individual seated in a wheelchair to transfer
from. In this embodiment, air connects are removed from the bottom
surface of the air chamber sensor 20 thus reducing the height of
the air cushion control system. The reduced height of the housing
is also important for the wheelchair user to get their legs under a
standard table. In this embodiment, compartments 100 provide space
for the batteries, air pump, air valve and other structures. The
low height housing structure 90 may be smaller than about 1/2 of an
inch in height. In some embodiments, the low height housing
structure 90 may be about 1/4 of an inch in height under the
buttocks area.
[0078] The low height housing structure 90 is comprised of a bottom
housing layer 92, a middle housing layer 94, and a top housing
layer 96. The bottom housing layer 92 is provided with a curved
bottom 98 for conforming to a sling-type wheelchair seat commonly
used. The bottom housing layer 92 is easily removable as it is
attached to middle housing layer 94 by screws or other means. The
bottom housing layer 92 may have ribs 106 for support. The ribs 106
and bottom housing layer 92 may be vacuum formed.
[0079] In practice, the bottom housing layer 92 may be removed if
it is desired to use the present invention with a wheelchair or
other chair having a flat surface. The present invention may be
provided to the consumer with a range of bottom housing layers 92
to accommodate different wheelchairs and accommodate different
sling-type wheelchairs. Sling-type wheelchairs may vary in sag from
about 1/2 inch to about 2 inches.
[0080] Top housing layer 96 may be provided with chases or vias
molded into the material of the top housing layer 94 to provide for
the wiring and air tubing. By using chases or vias, a reduction in
the height of the housing 30 is achieved. The top housing layer 96
may be molded to form the chases, vias, and compartments 100.
[0081] The middle housing layer 94 may be of a thin (approximately
1/8 of an inch) lightweight material such as aluminum or plastic
with a honeycomb interior. Plastic or Kraft paper may also be used
in forming the middle housing layer 94.
[0082] In the embodiment shown in FIGS. 11-13, the air cushion 20
comprises two layers of material. The two layers are welded
together with perimeter air connects 102 protruding from a seam
formed by the welding of the two layers. This provides air chamber
sensor 20 that does not have air connects below, thusly all air
connects may be in one plane. The magnet 25 may be attached or
integral to the upper layer of the air chamber sensor 20. Of
course, the perimeter air connects 102 may be used with any air
chamber sensor 20 of the present invention.
[0083] In another embodiment as shown in FIG. 14, the top layer 72
may be reduced to only cover a portion of the middle layer 74. The
reduced top layer 72 may provide greater flexibility for the air
chamber sensor 20 to inflate.
[0084] In another embodiment of the present invention, the housing
and the air chamber sensor may be enclosed by a cover. The cover
may be made of a washable material and may be closed with a zipper,
Velcro, or other closing means. The cover may have a non-skid
material attached or integral with the bottom of the cover to
maintain stability of the system on the wheelchair or other seating
surface. The cover may have holes therein for the adjustment
button, air connects, and other features.
* * * * *