CA2498007A1 - Hospital bed - Google Patents

Abstract

A hospital bed is provided which comprises a tilt sensor for compensating weight measurements when the bed is articulated. An optional diagnostic and control system to monitor electronic and other subsystems within the bed can be integrated into the bed.
The bed may further comprise a one-piece removable headboard. The bed may further have a footboard comprising a console and an equipment holder for securely supporting equipment without obstructing the console.

Description

MBM File No. J 364a-J 07 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 MBMFiIe No. 1364a-I07 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 MBM File No. 1364a-107 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;

MBM File No. 1364a-I07 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.

MBM File No. 1364a-107 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 MBMFiIe No. 1364a-107 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 MBM H'ile No. 1364a-107 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 MBM File No. 1364a-107 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 MBM File No. 1364x-107 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 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 MBM File No. 1364a-107 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 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 MBM File No. 1364a-107 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.

MBM File No. 1364a-107 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°

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

MBMFiIe No. 1364a-107 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 MBM File No. I j64a-l07 LC(3) + LC(1) * * LC(3) + LC(0) CG[X) = W H(X) 0.01 CG[Y) = W. H(Y} 0,01 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 MBM File No. 1364a-107 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 MBM File No. 1364a-!07 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 MBMFiIe No. 1364a-l07 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 MBMFiIe No, 1364a-l07 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 MBM File No. 1364a-107 interface includes subinterfaces for side rail consoles, footboard consoles, remote monitoring consoles, external alarm system, speakers, an entertainment system etc.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A device for supporting a patient and determining patient characteristics, said device comprising:
a) a base unit and two pairs of lift arms pivotally connected to said base;
b) a frame secured to the lift arms, said lift arms being configured to raise and lower the frame;
c) 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 d) 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 correlates the signals and data thereby providing a means for determining patient characteristics.