Note: Descriptions are shown in the official language in which they were submitted.
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HOSPITAL BED
FIELD OF THE INVENTION
This invention relates generally to a hospital bed and, more particularly, to
improvements
to the structure, functionality and maintenance of the bed.
BACKGROUND
Typical hospital beds are subjected to daily use by various hospital personnel
and
patients. Patients, medical professionals, maintenance staff and others
operate and move
beds according to the various requirements such as patient needs, and stresses
which
require sturdy components and reliable measurements.
The headboard needs to be moved or removed often for various tasks and in
emergency
situations. A removable headboard must be lightweight and sturdy so as to
facilitate easy
removal and replacement by the user. There is a need for a light, sturdy
headboard which
is easy to use and cost-effective to produce.
The footboard often is also used to hang other equipment on the top rail or
with another
device which is attached to and hangs from the footboard. The placement of
such
equipment can obscure a reading area or control panel located on the
footboard.
Furthermore, such equipment may fall off the headboard or other device,
thereby
resulting in damage. There is a need for an integral equipment holder within a
footboard
to accommodate the requirement to hang equipment but without compromising
access to
a control panel on the footboard or risking damage to the equipment.
The change in a patient's weight is recorded by medical professionals for
various reasons
at different times during a hospital stay. Scales are incorporated in beds
which can weigh
a load such as the patient. When load cells are used in the bed, the load
readings in a
horizontal bed are not the same as those in an articulated bed. The location
of a patient's
centre of gravity has been further used in a patient detection system, such as
the system
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described in US 6,$22,571 (the '571 patent) which issued to Conway on November
23,
2004. The '571 patent is incorporated herein by reference. In order to obtain
an accurate
weight measurement, patients who are in an articulated bed often have to be
repositioned
to the horizontal, which is inconvenient and disruptive. There is a need to
measure and a
patient's weight on a bed independent of the bed's angular position.
Hospital beds currently are equipped with a number of complex mechanical and
electrical
subsystems which provide various functions such as positioning, weight
monitoring, and
other functions related to the patient's care. Despite their inherent
complexity, these
systems need to be easy to operate by the user. The ease of use and operation
is of
critical importance, particularly in emergency situations. Due to the
complexity and
required minimal downtime for these beds, the status of such systems needs to
be
constantly monitored, which currently is performed by technicians in order to
ensure the
desired functionality of the bed is maintained. This form of monitoring and
potentially
diagnosis of problems with a bed can be both time consuming and costly.
Therefore there is a need for a control and diagnostic system for integration
into a
multifunctional bed that can overcome the identified problems in the prior art
and provide
the desired functionality with a reduced level of human interaction.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a hospital bed. In
accordance with one
aspect of the present invention, there is provided an apparatus for supporting
a patient
and determining patient characteristics, said apparatus comprising a base unit
and two
pairs of lift arms pivotally connected to said base; a frame secured to the
lift arms, said
lift arms being configured to raise and lower the frame; one or more load
sensors
operatively connected to the frame, said one or more load sensors electrically
connected
to a control unit that is configured to receive signals from the one or more
load sensors,
said signals relating to the weight of the patient; and a tilt sensor
operatively connected to
the frame, said tilt sensor connected to the control unit that is configured
to receive data
from the tilt sensor, said data representative of frame tilt; wherein said
control unit
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correlates the signals and data thereby providing a means for determining
patient
characteristics.
In accordance with another aspect of the present invention, there is provided
a diagnostic
and control system for a bed, said bed having integrated therein one or more
electronically controlled devices for providing one or more functions to the
bed, said
system comprising: a control subsystem electronically coupled to one or more
electronically controlled devices for transmission of data therebetween, said
control
system for initiating the functionality of the one or more electronically
controlled
devices, said control system collecting information relating to operational
conditions
representative of said one or more electronically controlled devices; and a
diagnostic
subsystem electronically coupled to the control subsystem for transmission of
data
therebetween, said control subsystem activating said diagnostic subsystem upon
detection
of an operational fault relating to the one or more electronically controlled
devices, said
diagnostic subsystem for receiving information from the control subsystem and
analysing
said information using one or more evaluation routines for the determination
of a
potential source of the operational fault.
In accordance with another aspect of the present invention, there is provided
a one-piece
removable headboard for a bed which is light and sturdy.
In accordance with another aspect of the present invention, there is provided
an
equipment holder connected to a bed footboard.
BRIEF DESCRIPTION OF THE DRAWINGS
This invention is described with particularity in the accompanying claims. The
further
features and benefits of this invention are better understood by reference to
the following
detailed description, as well as by reference to the following drawings in
which:
Figure 1 illustrates a perspective view of a hospital bed according to the
present
invention;
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Figure 2 is a perspective view of an embodiment depicting the placement of
load cells
within the hospital bed frame;
Figure 3 is an exploded perspective view depicting the placement of an angle
sensor
within the hospital bed frame;
Figure 4A is front view of the headboard of the present invention;
Figure 4B is a side view of the headboard depicted in Figure 4a;
Figure 4C is a bottom view of the headboard depicted in Figure 4a;
Figure 4D is a perspective view of the headboard depicted in Figure 4a;
Figure SA is an exploded perspective view depicting the footboard, holder
support and
equipment holder;
Figure 5B is a perspective view depicting the assembled footboard, holder
support and
equipment holder;
Figure 6 depicts the functional block diagram of an accelerometer used in an
embodiment
of the present invention;
Figure 7 displays a tilt sensor circuit of the present invention;
Figure 8A depicts a horizontal bed with a load X; and
Figure 8B depicts an articulated bed at angle 8.
Figure 9 illustrates a part of a user interface embedded into the bed of
Figure 1.
Figuxe 10 illustrates the window content of a step in a series of user-bed
interaction
processes displayed on a detached device such as a general purpose computer.
Figure 11 illustrates part of a user interface intended for use by the bedded
person.
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Figure 12 schematically illustrates the electrical architecture of a bed
control and
diagnostic system.
Figure 13 illustrates a load cell system which is used for monitoring movement
and mass
or weight of a bedded person.
Figure 14A illustrates an embodiment of a motor control and drive system.
Figure 14B illustrates an embodiment of an interface controller.
Figure 14C illustrates an embodiment of a scale subsystem.
Figure 14D illustrates an embodiment of a power supply system.
Figure 14E illustrates an embodiment of a communication interface.
DETAILED DESCRIPTION
The present invention provides a hospital bed that comprises a tilt sensor for
compensating weight measurements when the bed is articulated. The bed may
further
comprise a diagnostic and control system to monitor a plurality of electronic
and other
subsystems within the bed. The bed may further comprise a one-piece removable
headboard. The bed may further comprise a footboard comprising a console and
an
equipment holder for securely supporting equipment without obstructing the
console.
Referring to Figure 1, more specifically there is shown a hospital bed 10
according to the
present invention. The bed 10 has an articulated bed surface including a foot
section 1I, a
seat section 9 and a head section 15 that are supported by a frame 22 and can
also
comprise a headboard 12 and a footboard 13. The frame 22 is supported on a
base unit
14 by generally upright pivot plates 18, 19, 20 and 21 extending upwardly from
the base
unit 14. As illustrated, two pivot plates 18 and 21 are pivotally attached to
the head
portion 27 of the frame 22, and two pivot plates 19 and 20 are pivotally
attached to the
foot portion 28 of frame 22. Thus, the bed can be raised or lowered when the
lift arms
18, 21, and 19, 20 rotate in order to provide vertical adjustment of the bed
10 with respect
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to a horizontal plane. Preferably, the vertical adjustment of the bed 10 can
be further
facilitated by a motor or a hydraulic lift (not shown).
If it is desired to render the bed 10 easily movable, a plurality of wheels 16
can be
provided on the base unit 14, typically at the four comers thereof. A
brake/steer pedal 17
extends from the base unit 14 to facilitate locking and unlocking of the
wheels 16.
A lift arm 24 is pivotally attached to frame 22 at a pivot point 24a at one
end and to the
head section 15 at pivot point 24b (not shown) at another end. Similarly, a
lift arm 25 is
also attached to the other side of the frame 22 at pivot point 25a (not shown)
at one end
and to the head section 15 at pivot point 25b at the other end. The lift arms
24, 25 can be
attached to the frame 22 and the head section 15 by a bolt or other fastening
means that
secures the lift arms 24, 25 to the frame 22 and the head section 15, while
still allowing
the lift arms 24, 25 to pivot at the pivot points 24a and 25a, and 24b and
25b.
Accordingly, transverse movement of the head section 15 toward and away from
the foot
section 11 will cause the respective lift arms 24, 25 to rotate together about
the associated
pivot points 24a, 25a, and 24b, 25b. In a similar manner, the foot section can
be
articulated with lift arms 34 and 35 which are pivotally attached at one end
to frame 22
and at a distal end thereof to foot section 11, respectively, to provide for
elevation of the
foot section 11 with respect to the horizontal plane of the frame 22. As a
result, the foot
section 11 and the head section 15 can be configured and positioned at various
degrees of
inclination with respect to the seat section 9, which is fixed in the
horizontal plane.
The bed 10 further comprises one or more sensors (not shown) which are
connected to a
control and diagnostic system. One or more Ioad cells to measure the weight on
the bed
are located in positions where the load can be read. Figure 2 illustrates an
embodiment
where four such load cells are placed in the four corners of frame 22. One or
more angle
sensors such as accelerometers can also be positioned within the bed. Figure 3
illustrates
an embodiment where a tilt sensor circuit board comprising an angle sensor is
attached to
the head section of frame 22.
The sensors are connected to at least one microprocessor or other computing
device (not
shown), which can control the sensors and provide data for functions such as
error
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detection, load calculation and angular displacement in relation to gravity,
among other
data.
The headboard 12 and footboard 13 according to one embodiment of the present
invention are individually molded using a gas-assist injection molding
process. Gas-
assist injection molding is a well-known process that utilizes an inert gas
(normally
nitrogen) to create one or more hollow channels within an injection-molded
plastic part.
During the process, resin such as polypropylene is injected into the closed
mold. It is
understood that any other suitable material, such as ABS, nylon, or any other
resin
compatible with the process may be used. At the end of the filling stage, the
gas such as
nitrogen gas is injected into the still liquid core of the molding. From
there, the gas
follows the path of the least resistance and replaces the thick molten
sections with gas-
filled channels. Next, gas pressure packs the plastic against the mold cavity
surface,
compensating for volumetric shrinkage until the part solidifies. Finally, the
gas is vented
to atmosphere or recycled. Advantages to using such a process over other
molding
processes are known to a worker skilled in the art.
The headboard 12 is made of one piece. Figures ~A-D depict the headboard of
one
embodiment. The mold is designed to produce a curved removable headboard which
is
sturdy, very light, and easy to access and manipulate by the user.
Typically, medical professionals require access to the head section of a
hospital bed to
position equipment proximate to the patient's head. In urgent situations, such
as when
the patient requires immediate medical attention, immediate access to the head
section is
often required. In both such situations, the headboard must be moved away from
the
access area or completely removed from the bed. For a headboard that is
removed from
the bed, it is desirable that such headboard be as light as possible, while
still maintaining
sufficient structural integrity. Once removed from the bed, the headboard is
typically
place within the near vicinity, such as by leaning against a support surface
such as a wall
proximate to the bed.
Since the headboard of the present invention is a one-piece unit, it is less
costly to
manufacture than headboards which have multiple parts and require assembly.
With no
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additional parts to attach to the headboard, there are also fewer parts that
are subject to
mechanical failure.
The design of the headboard mold, and thus the bed's headboard, is unique. The
headboard 12 has a generally rectangular shape. A generally tubular channel
102, which
is hollow, borders the headboard 12 at both sides 104, 106 and the top 108,
tapering
inwards towards the bottom 110 and ending in two ends 112, I14 which project
below
the generally rectangular portion 116 of the headboard 12. Proximate to each
end 112,
114 is a generally oval post 118 for removably mounting the headboard 12 into
mounting
sockets (not shown) which are affixed to the bed proximate the top of the head
section
15. Optionally, in order for the headboard 12 to avoid being damaged when it
is resting
on the floor against a wall for example, a cap or cover 120, made of a non-
stick material
such as rubber, can be fitted around each post 118. Additionally, the cap 120
may ensure
a snug fit into the mounting sockets and minimize wear on the posts 118. The
cap 120
can be attached to or molded into the headboard 12.
The generally rectangular portion 116 of the headboard 12 comprises a flat
thin layer of
resin or headboard skin 122 which joins the tubular channel 102. In one
embodiment of
the present invention, the headboard skin 122 has a thickness of about 1/8
inch. It will be
appreciated that the thickness of the headboard skin 122 and tubular channel
102 is
proportional to the amount of material required and the weight of the
headboard 12. The
headboard 12 can also be translucent or transparent for easier monitoring of
the patient
and better visibility.
The headboard 12 has a gradual concave shape 124 such that when the posts 118
are
fitted into the mounting sockets, the centre of the headboard skin 122 is
furthest from the
bed's head section 15. Given that the headboard 12 is formed by a process
which uses a
minimal amount of resin, the concave shape 124 provides additional stability
to the
headboard 12.
In operation, users, such as medical professionals, can seize the tubular
channel 102 at
both sides 104, 106 of the headboard and lift upwards for removal of the
headboard 12.
Installation requires lining up over and inserting each post 118 inside the
mounting
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sockets. Optionally, one or more holes I26 of various shapes and sizes can be
located
within the skin to allow users to conveniently grasp the headboard 12 prior to
removal or
installation.
Figures SA and B depict the footboard 13 of the present invention. The
footboard 13 is
formed using a similar gas-assist injection molding process as the headboard
12. The
footboard 13 also has a generally rectangular shape. A generally tubular
channel 802,
which is hollow, borders the footboard 13 at both sides 804, 806 and the top
808, tapering
inwards towards the bottom 810 and ending in two ends 812, 814 which project
below
the generally rectangular portion of the footboard 13.
Proximate to each end 812, 814 is a generally oval post 816 for removably
mounting the
footboard 13 into mounting sockets (not shown) which are affixed to the bed
10. Similar
to the cap 120 used with each post of the headboard 12, a cap 818 can be
fitted around
each post 816.
The generally rectangular portion of the footboard 13 is a thin layer of resin
or footboard
skin which joins the tubular channel 802. Optionally, one or more holes 819 of
various
shapes and sizes can be located within the skin to allow users to conveniently
grasp the
footboard 13 prior to removal or installation.
The footboard is molded to be attached to two additional components, a control
board
(not shown) at board zone 820 and a holder support 822. Since a control board
is
attached to the footboard 13, a back panel 824 needs to be attached to the
footboard 13 to
secure and protect the control board's electronic components. The control
board has a
display or console with which the user can interface.
The console (not shown) can be of any shape or size. The board zone 820 is
generally
structured to complement the interface. Users such as medical professionals,
require an
unobstructed view and access to the console. In one embodiment, a generally
rectangular
control board and console can be located at the board zone 820 in the upper
middle half
of the footboard 13. The console may optionally be positioned at an angle
relative to the
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MBMFiIe No. 1364a-!07
vertical such that a user peering down at the console from a position above is
afforded an
unobstructed perspective of the console.
Below the console, generally in the lower middle half of the footboard 13 is
the holder
support 822 comprising a horizontally disposed equipment holder bar 828. The
holder
support 822 is connected to the footboard 13 such as with screws 826, adhesive
or other
connection means. The holder bar 828 is useful to hang extra equipment (not
shown).
As required, equipment such as pumps can be temporarily positioned on the
holder bar
828, as opposed to the top edge 808 of the footboard I3 which could otherwise
obstruct
the view and access to the console. In addition, use of the holder bar 828 to
hang
equipment which is located lower than and away from the interface minimizes
the risk of
damage to the console and footboard 13. Such equipment can freely hang. Using
the
holder bar 828 to hang equipment also results in less motion generated on the
bed 10,
which could otherwise disrupt the patient. Additional advantages to users are
readily
apparent including reducing the risk of damaged equipment which previously was
hung
on the top edge 808 of the footboard 13 and would subsequently fall or slide
off.
In referring to Figure 2, load cells 902 can be positioned at one or more
locations in
communication with the bed such that measurements of the load signals can be
made for
various reasons such as determining the weight gain or loss of the patient
over time and
the patient's centre of gravity at any instant. The load cells 902 in this
embodiment are
located on the four corners of the frame 22.
One difficulty with determining the patient's weight is when the bed is
articulated at
positions other than the base position at which the load cells are calibrated.
When the
bed is articulated at various angles, for example, the raw measurements on
typical load
cells will not reflect a patient's accurate weight since the load's centre of
gravity shifts,
thereby affecting the individual load sensed by each load cell.
In the present invention, the load cell measurements can be used together with
other
measured or input information, such as the articulation angle of a section or
the entire
frame in order to determine, for example, the patient's weight. When the bed
is
articulated to the Trendelenburg and reverse Trendelenburg positions, the
actual load can
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be calculated by knowing the angle of the frame and respective loads measured
by each
load cell, independent of the frame's position. One or more angle sensors can
determine
the angular position of the frame while the load's centre of gravity shifts.
Medical personnel require accurate readings of the patient's weight
independent of the
bed's articulation. Such a measurement is possible by calculating the bed's
angle relative
to baseline and load cell measurements.
A tilt sensor which incorporates an accelerometer is attached to any part of
the bed frame
which can be elevated and articulated. Figure 3 depicts an exploded view of an
embodiment of a tilt sensor 1000 attached to the top 27 of frame 22.
The tilt sensor 1000 is read and measurements are calculated after a given
time period,
such as 50 ms. It can run continuously, intermittently or upon command from
the user,
such as when the frame 22 is in an articulated position. The tilt sensor 1000
can be
connected to at least one motherboard or any electronic board via a
communications
means 1002 such as a wire, fibre optic, or wireless connection.
In one embodiment, the tilt sensor 1000 is designed with a solid state
accelerometer, such
as the ADXL202E accelerometer from Analog Devices of One Technology Way,
Norwood, MA. Other accelerometers may also be used.
The accelerometer of this embodiment is a 2-axis acceleration sensor with a
direct
interface to low-cost microcontrollers. This interface is possible through a
duty cycle
output.
The outputs of this accelerometer can be analog or digital signals whose duty
cycles
(ratio of the pulse width to the total period) are proportional to
acceleration. The outputs
can be directly measured with an integrated microprocessor counter, without
any external
converter.
Figure 6 depicts the functional block diagram of the accelerometer used in
this
embodiment. For each axis, a circuit output converts the signal into a
modulated duty
cycle that is decoded by the microprocessor. The accelerometer of this
embodiment must
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MBM File No. /3649-107
be capable of measuring positive and negative accelerations to at least +- 2
g, so as to
measure static acceleration forces such as gravity and therefore be used in a
tilt sensor.
Theoretically, a 0 g acceleration produces a 50% nominal duty cycle.
Acceleration is
calculated as follows:
A(g)=(T1/T2-0.5)/12.5%
T2(s) - RgET (~) / 125 Ms2
The 12.5% corresponds to the theoretical gain of the accelerometer. When used
as a tilt
sensor, the accelerometer uses the force of gravity as the input vector to
determine the
orientation of the object in space. The accelerometer is more sensitive to
tilt when its
reading axis is perpendicular to the force of gravity, that is to say,
parallel to the earth's
surface. When the accelerometer is orientated on axis to gravity, that is to
say, near its +
1 g or - 1 g reading, the change in output acceleration per degree of tilt is
negligible.
When the accelerometer is perpendicular, the output varies nearly 17.5 mg per
degree of
tilt, but at 45 degrees the output only varies 12.2 mg by degree and the
resolution
declines. This is illustrated in the following table:
o °. 10
Y
sorrow viErr
x oWp~e Y omvul (sf'
X Aais a pw 4 pn
Orh~4Mon Opnir o1 Dpm of
b HoAson (') X Output (o! Tilt (m~ Y OvtpW (py nn (mpj
~0 -1.000 -0.2 0.000 17.9
-76 -0.911 4.~ 0.269 11.1
-eo -o.ee1 9.s o.a°o /9.z
-15 -0.707 122 0.707 1t1
-X10 -0.600 19.0 0.116 1.1
-1s ~saa le.e o.les ~.7
a o.oo0 17.s l.ooo o.s
1a o.is1 11.1 o.le1 -r.<
9o o.aoo ls.s o.ee6 -a.a
s9 0.707 12.~ 0.701 -122
a0 0.111 1.1 0.900 -16.0
7a 0.111 ~.7 0.251 -11.1
1.000 O.Z 0.000 -17.6
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It is also to be noted that the gravity value varies according to the sine of
the angle, which
also influences the precision and consequently the orientation of the sensor
of this
embodiment. The sensor precision can be improved by using both Xout and Yout
signals
in the angular determination. By doing so, the low sensitivity range (around 0
degrees) is
reduced.
The tilt sensor circuit used in one embodiment was therefore designed from the
Analog
Devices accelerometer following the recommended design parameters. The
schematic of
the circuit for this embodiment is shown at Figure 7.
D 1 is added to protect the circuitry against polarity inversion.
RseT value was set to 1 MS2. Therefore, T2 value is:
T2 = 1 MS2 / 125 MS2 = 0.008
T2 total period is thus 8 ms, therefore giving a 125 Hz frequency.
In order to determine the actual values of the zero and the gain, the tilt
sensor circuit must
be calibrated. Since the zero and the gain are known after calibration, only
T1/T2 is
unknown. It is this duty cycle that varies according to the angle. The
microprocessor
thus takes this reading and calculates the corresponding angle.
To calibrate a tilt sensor circuit, two duty cycle readings must be taken at
known angles.
With these two PWM (pulse width modulation) readings, the two unknowns (zero
and
gain) can be computed. It is preferable to take a PWM reading when the tilt
sensor is at
its zero position, as readings are usually precise at this position. This also
provides a
reading of the PWM value corresponding to the zero of the sensor, since a
sensor in zero
position gives 0 g.
The tilt sensors of this embodiment are used to indicate the angle of the
mattress support
sections, such as the Trendelenburg and reverse Trendelenburg angles. A
compensation
of the weight read by the load cells according to the Trendelenburg angle can
then be
computed. Consequently, the weight value displayed is thus in the required
margin.
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As previously indicated, the axis in which the tilt sensor is positioned is
important to
obtain precise readings. For example, the position of a head section may vary
between 0
and 80 degrees. Given that the tilt sensor of the embodiment is more precise
from -45 to
45 degrees than from 0 to 90 degrees, the tilt sensor would be positioned in
the bed so
that the zero of the sensor is at 45 degrees. In computation, one would
account for this
position by adding 45 degrees to each angle read.
The calculation of load and calibration values is readily apparent in
referring to Figures
8A and B, where:
X patient load;
Y+ weight of bed frame which changes with the Trendelenburg angle;
Z+ load cell factor which is not influenced by the Trendelenburg angle;
Y_ weight of bed frame which changes with the reverse Trendelenburg angle;
Z_ load cell factor which is not influenced by the reverse Trendelenburg
angle;
8 bed frame angle; and
T load cell readings.
At6=0°, To°= X+Y++Z+
At6=12°,T~2°=(X++Y+)cos6+Z+
During calibration, the bed frame load without the patient is measured at
0° and at 12°,
providing:
X=0
To° = first measurement at 0°
T,2° = second measurement at 12°
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MBM File No. 1369a-I07
To°=Y++Z+
T,z°=Y+cos 8+Z+
Y+ = To° _ Z+
Y+cose=T,z°-Z+
Y+ = T,z° - Z+
cos A
To°-Z+=T~z°-Z+
cos 8
Z+ = T,z° - To° cos 8
- cos 8
if 8 = 12°
Z+ = T,z° - To° cos 12°
1 - cos 12°
Z+ = (T,z° - To * 0.97815) * 45.761565
Y+ = To° _ Z+
Z+ and Y+ for each load cell are determined during calibration. In a similar
manner, Z.
and Y_ are determined using measurements at 0° and -12°,
providing:
Z . _ (T.,z° - To° * 0.97815) * 45.761565
Y.=To°-Z.
When determining the patient's weight, X, the following calculations are made
for each
load cell:
T9=(X+Y)cosA+Z
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Te=Xcos6+Ycos4+Z
XcosA=Te-Ycos6-Z
X=Te-Ycos6-Z
cos H
X=Te-Z
_Y
cos 8
The processor determines the bed's angular position (Trendelenburg or reverse
Trendelenburg) prior to choosing Y+ or Y. and Z+ or Z _. When the bed angle is
0°, the
processor chooses Y+ and Z+ to calculate the load.
The centre of gravity can be calculated as follows, using for example four
load cells
positioned in a rectangle relative to the patient:
X length (head to foot)
Y width (left to right)
LC(0) load cell value foot left
LC(1) load cell value head right
LC(2) load cell value foot right
LC(3) load cell value head left
W total weight of the patient
H(X) distance between the head load cells and foot load cells
H(Y) distance between the right load cells and left load cells
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LC(3) + LC(1) * * LC(3) + LC(0)
CG[X) = W H(X) 0.01 CG[Y) = W. H(Y} 0,01
100 100
Figure 9 illustrates a schematic view of a console which can be part of a user
interface
embedded into a bed. The console can be integrated into the footboard of the
bed
illustrated in Figure 1 and provide access to the bed's functions. The console
has back lit
zone indicators 210 which can indicate a set zone mode of the bed for
indicating a preset
restriction level for movement of a bedded person. Indicators 210 can also be
multi-color
back lit to provide an indication of whether the system is in an armed or a
disarmed state.
Button 220 can be used to set and switch between the zone alarm as indicated
by the zone
alarm indicators 210. Button 230 can be arms or disarms the zone alarm
functionality in a
toggling fashion. Button 230 can be sectional or full color or mufti-color
back lit to
indicate an armed or disarmed state of the zone alarm system. Interface
elements 240 can
be used to raise or lower the bed support surface. While pushing the arrow-up
button the
bed raises and while pushing the arrow-down button the bed lowers. Pushing and
holding
both buttons may cause the movement to stop or continue the movement according
to the
button which was pressed first. Button 250 can lock out some or all
functionality
accessible through this or other consoles until the button 250 is pressed
again. Buttons
260 and 270 can be used to lock-out access to reorient the respective head and
knee
sections of the bed. Button 280 when pressed causes the bed to assume a
cardiac position
or other predetermined shape of the bed support surface. Each of buttons 290
and 291
when pressed individually inclines or reclines the overall bed support surface
without
affecting the shape of the bed support surface. Interface elements 265 and 275
provide
button groups which when pressed can reorient the head or the knee sections of
the bed
and can be used in order to achieve respective desired angles between the
upper body and
the upper leg, as well as the upper leg and the lower leg of a bedded person.
Display 205
can be used to display information about certain functions or the state of
certain parts of
the bed and its system components. Button group 215 can be used to scroll
through
information which is available in form of a menu for display but exceeds the
amount of
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information which can be displayed simultaneously on display 205. Buttons 217
and 219
can be used to select or enter information and to interact with the menu
following a
command and control concept.
Figure 10 illustrates the window content of a step in a series of user-bed
interaction
processes that can be displayed on a detached device such as a general purpose
computer.
This is part of an interface which for example can provide remote access to
control,
diagnose, or monitor functions of the bed system. The interface can provide
functions to
select certain components from a list of components or subsystems 310 of the
bed system
for detailed investigation. The user interface may change its look and feel by
changing
some or all of its user interface components when selecting to investigate a
specific
component of the bed system. The user interface can provide and display
information in a
categorized graphical fashion and can utilize a button status field 320, a
motor status field
330, fields for monitoring vital information about a bedded person etc. The
user interface
can also provide a menu system 340 to select from providing access to
different aspects
of interaction of the bed system such as for example, a monitoring interface,
a
maintenance interface, an operator interface etc. Switching between these
modes may
require authorization and may be password or security code protected.
Figure 11 illustrates an embodiment of a part of the user interface intended
for use by the
bedded person. As illustrated, the user interface for the bedded person can
provide access
to reclining functions 410, emergency call functions 420 or control of
entertainment
equipment 430.
Figure 12 illustrates a schematic diagram of the system architecture 500 of a
bed control
and diagnostic system. The architecture can be divided into a number of user
interface
and control subsystem components. The system architecture comprises a power or
AC
control system 510 for supplying electrical power, an actuator subsystem 515
providing
ability for positioning and orienting parts of the bed, a number of sensor and
detector
subsystems for sensing and detecting the state of parts of the bed, and a
diagnostic
subsystem as indicated. The diagnostic subsystem can interact with the sensor
and
detector subsystem or it can have its own redundant sensor and detector
system. The user
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interface subsystem can comprise a number of control consoles 520, 525, 530,
and 535
comprising indication or display systems. The display systems can have a touch
screen
531 or a regular display with separate buttons. The sensor system can comprise
a scale
subsystem 540 including a load cell system and tilt sensor. The system
architecture can
further comprise a room or other interface 550 for communicating information
from the
bed to a remote user interface system or vice versa.
Figure 13 illustrates the information made available by a load cell system 600
which is
used for monitoring movement of a bedded person. The system can be integrated
into the
bed or can be part of a person support element such as a mattress. In
addition, the load
cell system can comprise a number of load cells or load sensors for example a
load cell
which can be embedded in the bed proximally positioned at each of a bedded
person's
limbs and optionally at the center of the bed. The load cell system also can
be comprised
of a mesh of load cells for example. The signals from the load cells can be
monitored and
processed by a processing unit in the load cell system or a central processing
unit capable
of monitoring, processing, and controlling signals from the bed's subsystems.
Instead of
forming part of a support element, the load cell system can be integrated into
the surface
of the bed frame. The load cell system can provide a measure for the pressure,
weight, or
mass load of a certain load cell, for example foot left 620 or right 640 load
cell values
and head left 650 or right 630 load cell values and additional information
about the
location of the centre of gravity.
Figures 14A schematically illustrates an embodiment of the motor control
subsystem
with a number of attached actuators and limit switches. It is understood that,
depending
on the functionality of the bed, there can be a different number of actuators
or limit
switches than illustrated. In this embodiment the surface of the bed can be
shaped by
orienting a head, thigh, and a foot section where the support surface for a
bedded person
is intended to fold and provide an adjustable angle between the upper body and
the thigh
as well as under the knee between the thigh and the lower leg. The head
actuator 7010
can position the end of the head section, and the thigh actuator 7020 can
position the knee
section of the bed support surface relative to an even or flat support
structure. The HI-LO
head actuator 7030 can position the head end of the even support structure
relative to the
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frame of the bed which is in contact with the floor. The HI-LO foot actuator
7040 can
position the foot end of the even support structure relative to the frame of
the bed, for
example. The two HI-LO actuators can pivot the support surface horizontally
whereas the
head and the thigh actuator can shape the support surface by pivotally
adjusting sections
of the bed support surface.
The motor control subsystem is connected to a number of limit switch or angle
sensor
systems 7050 which ensures that the actuators do not move or position parts
beyond
predetermined limit angles or distances. When a part or section of the bed
reaches a
predetermined limit position while moving, the motor control subsystem can
receive a
status change signal via one or more limit sensor signals and can interrupt
the respective
movement. The motor control subsystem can have a safety control feature that
does not
allow any further continued movement in that same direction or orientation
unless the
limit condition indicated by the limit sensor system is resolved. Provided
that no
movement of other degrees of freedom of the bed takes place, the limit
condition
typically can be resolved by reversing the original movement.
Figure 14B schematically illustrates an embodiment of the user interface
controller 7100
with a number of attached user interface consoles. The bed can have a number
of user-
interface consoles, each providing access to a certain set of bed system
functions. For
example the bed can have user interface consoles integrated into one or both
of the side
rails of the bed providing easy access to certain bed system functions for a
bedded person
or for a person at the side of the bed. The bed can also have a user interface
console
located at the foot or the head section of the bed. Each such interface
console may be
integrated into a respective foot or head board of the bed for example. A foot
7130 or a
head interface console may provide access to a set of bed system functions
different from
each other as well as different from the side rail consoles. There can be
inner 7110 or
outer 7120 side rail consoles intended for access from within or from outside
of the bed.
An embodiment of a side rail console is illustrated in Figure 11 and an
embodiment of a
foot board interface console is illustrated in Figure 9. The foot board
console can have a
display system 7150 included. The display system can be a touch screen display
or a
simple passive display system with a separate input system as illustrated in
Figure 9. In
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addition the interface controller can have a remote control interface 7160 to
which a
remote console can be connected. The remote control interface can provide
wired or
wireless connection of a special purpose or a general purpose computing device
7170 for
example. A number of different bus systems and control protocols are available
to
communicate through the remote control interface as known to a person skilled
in the art.
The interface controller rnay also provide a number of additional control or
remote
control interfaces 7180.
Figure 14C illustrates a part of a scale subsystem 7200. The scale subsystem
can connect
to a number of load sensors or load cells. The number of load sensors can be
different
from that illustrated. In this embodiment, four load sensors 7210, 7220, 7230,
7240 which
are capable of sensing pressure and can be calibrated to provide a measure of
force or
mass applied to each sensor are attached to the scale subsystem control
interface 7250.
The scale subsystem controller can process signals incoming from the load
cells and can
be used to detect the status of a bedded person. The scale control subsystem
can be
configured to provide a messaging signal or to alert monitoring personnel
through an
external alarm system interface 7260 for example. When each load cell is
properly
calibrated, the scale control subsystem can also provide a measure of the
weight of a
bedded person, which is then compensated by the angle of the bed to provide
the actual
weight. The weight information can be utilized and can also be recorded in
another
subsystem of the bed which may be desired for patient monitoring for example.
As
previously described, the angle of the bed and the load sensor measurements
are used to
calculate the patient's actual weight, independent of the bed's position.
Figure 14D illustrates an embodiment of a power supply system. The power
supply
system may include an adaptation subsystem including a transformer and an
adaptive
wiring and plugging subsystem to achieve compatibility with standard power
outlets and
the different voltage standards of other regions or countries.
Figure 14E schematically illustrates the communication interface of the CAN
board
controller for communication with other components of the bed. The
communications
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interface includes subinterfaces for side rail consoles, footboard consoles,
remote
monitoring consoles, external alarm system, speakers, an entertainment system
etc.
23
