Patent Application
20230233102
The present disclosure relates to person support apparatuses, such as beds, cots, stretchers, operating tables, recliners, or the like. More specifically, the present disclosure relates to person support apparatuses that include sensors for detecting obstacles and sensors for detecting when an occupant of the person support apparatus has exited therefrom, or may be about to exit therefrom.
Existing hospital beds and/or stretchers often include a bed exit system that is adapted to detect when a patient has exited the bed, or when a patient may be about to exit the bed. Typically, such beds include circuitry for providing an audio or visual alert when such an exit or pre-exit situation is detected. In many cases, the bed or stretchers include circuitry for transmitting a signal to a remote location, such as a nurses' station, so that the appropriate caregivers are notified of the exit, or pre-exit condition, and can respond appropriately. Existing exit detection systems often rely on an analysis of the outputs of multiple load cells. In some existing systems, the load cells outputs are monitored to compute a location of the occupant and if that location moves out of a defined area, an exit alert is issued. In other existing systems, the load cell outputs are monitored and one or more ratios of the forces detected by one or more of the load cells are computed. If the one or more ratios change by an amount greater than a threshold amount, an exit alert is issued.
According to various embodiments, the present disclosure provides an improved person support apparatus having an exit detection system that reacts to obstruction detection. The exit detection system can react by compensating for the obstruction, deactivating the bed exit system until the obstruction is removed, or by issuing an exit alert. By taking one or more of these actions, the improved person support apparatus is able to avoid situations where its exit detection system might otherwise experience an error, or generate an unreliable assessment of the patient's position and/or movement, due to the obstruction exerting forces on the force sensors of the exit detection system. That is, the forces exerted by the obstruction on the force sensors might otherwise be interpreted as forces due to patient movement, which could incorrectly lead to an exit alert being issued when such an alert is not correct, or which could incorrectly lead to no exit alert being issued when such an alert would be correct. The improved person support apparatus therefore helps overcome reliability issues with its exit detection system when an obstruction is encountered.
In some embodiments, the exit detection system may be configured to automatically attempt to compensate for errors introduced into its force sensor readings from the impact with an obstruction. In such embodiments, the compensation may include shifting a calculated center of gravity of the patient by an amount equal to the shift caused by contact with the obstruction, and/or it may involve changing a size, shape, and/or position of one or more zones in order account for the contact with the obstruction (in those embodiments wherein the exit detection system is configured to issue an alert when the calculated center of gravity goes outside one of the zones).
According to one embodiment of the present disclosure, a person support apparatus is provided that includes a litter frame, a lift system, a support deck, an obstruction sensor, an exit detection system, and a controller. The lift system is adapted to raise and lower a height of the litter frame. The support deck is supported on the litter frame and adapted to support thereon an occupant of the person support apparatus. The obstruction sensor is adapted to detect when the litter frame contacts an obstruction during movement of the litter frame. The exit detection system is adapted to be in an armed state and a disarmed state. When in the armed state, the exit detection system is adapted to issue an exit alert in response to the occupant of the person support apparatus moving toward exiting the person support apparatus. When in the disarmed state, the exit detection system is adapted to not issue the exit alert in response to an occupant of the person support apparatus moving toward exiting the person support apparatus. The exit detection system comprises a plurality of force sensors adapted to output signals corresponding to downward forces exerted on the litter frame. The controller is in communication with the plurality of force sensors, the exit detection system, and the obstruction sensor. The controller is further adapted to automatically switch the exit detection system from the armed state to the disarmed state in response to the obstruction sensor detecting contact with an obstruction.
According to other aspects of the present disclosure, the person support apparatus may be adapted to automatically send a notification to a remote server in response to detecting the contact with the obstruction, wherein the notification indicates that the controller has switched the exit detection system to the disarmed state.
In some embodiments, the controller is further adapted to automatically switch the exit detection system back to the armed state from the disarmed state in response to the obstruction sensor no longer detecting contact with the obstruction.
In some embodiments, the obstruction sensor is attached to an underside of the litter frame.
The exit detection system, in some embodiments, is adapted, when in the armed state, to calculate a center of gravity of the occupant, to compare the calculated center of gravity of the occupant to a boundary of a zone, and to issue the exit alert if the calculated center of gravity is outside of the boundary of the zone. In such embodiments, the controller may further be adapted change at least one of a size, shape, or location of the zone in response to movement of a component of the person support apparatus.
The person support apparatus, in some embodiments, may further comprise a second obstruction sensor, in which case the controller is adapted to automatically switch the exit detection system from the armed state to the disarmed state in response to either the first obstruction sensor or the second obstruction sensor detecting contact with an obstruction.
According to another embodiment of the present disclosure, a person support apparatus is provided that includes a litter frame, a lift system, a support deck, an obstruction sensor, an exit detection system, and a controller. The lift system is adapted to raise and lower a height of the litter frame. The support deck is supported on the litter frame and adapted to support thereon an occupant of the person support apparatus. The obstruction sensor is adapted to detect when the litter frame contacts an obstruction during movement of the litter frame. The exit detection system is adapted to be in an armed state and a disarmed state. When in the armed state, the exit detection system is adapted to issue an exit alert in response to the occupant of the person support apparatus moving toward exiting the person support apparatus. When in the disarmed state, the exit detection system is adapted to not issue the exit alert in response to an occupant of the person support apparatus moving toward exiting the person support apparatus. The exit detection system comprises a plurality of force sensors adapted to output signals corresponding to downward forces exerted on the litter frame. The controller is in communication with the plurality of force sensors, the exit detection system, and the obstruction sensor. The controller is further adapted to automatically issue the exit alert in response to the obstruction sensor detecting contact with an obstruction when the exit detection system is in the armed state.
According to other aspects of the present disclosure, the controller may further be adapted to not issue the exit alert in response to the obstruction sensor detecting contact with the obstruction when the exit detection system in is the disarmed state.
In some embodiments, the exit alert includes transmitting an exit alert message to a remote server.
In some embodiments, the controller is further adapted to automatically terminate the exit alert in response to the obstruction sensor no longer detecting contact with the obstruction.
The controller, in some embodiments, may further be adapted to issue an obstruction alert in response to the obstruction sensor detecting contact with the obstruction when the exit detection system is in the disarmed state.
In some embodiments, the person support apparatus further comprises a second obstruction sensor adapted to detect when the litter frame contacts an obstruction during movement of the litter frame. In such embodiments, the controller is adapted to automatically issue the exit alert in response to either the obstruction sensor or the second obstruction sensor detecting contact with the obstruction when the exit detection system is in the armed state.
According to still another embodiment of the present disclosure, a person support apparatus is provided that includes a litter frame, a lift system, a support deck, an obstruction sensor, an exit detection system, and a controller. The lift system is adapted to raise and lower a height of the litter frame. The support deck is supported on the litter frame and adapted to support thereon an occupant of the person support apparatus. The obstruction sensor is adapted to detect when the litter frame contacts an obstruction during movement of the litter frame. The exit detection system is adapted to be in an armed state and a disarmed state. When in the armed state, the exit detection system is adapted to issue an exit alert in response to the occupant of the person support apparatus moving toward exiting the person support apparatus. When in the disarmed state, the exit detection system is adapted to not issue the exit alert in response to an occupant of the person support apparatus moving toward exiting the person support apparatus. The exit detection system comprises a plurality of force sensors adapted to output signals corresponding to downward forces exerted on the litter frame. The controller is in communication with the plurality of force sensors, the exit detection system, and the obstruction sensor. The controller is further adapted to automatically change operation of the exit detection system in a first manner in response to the obstruction sensor detecting contact with an obstruction when the exit detection system is in the armed state.
According to other aspects of the present disclosure, the exit detection system may be adapted operate with a plurality of different sensitivity levels, and the controller may be adapted to change the operation of the exit detection system in the first manner by switching the exit detection system from a first sensitivity level to a second sensitivity level. In such embodiments, the second sensitivity level is less sensitive than the first sensitivity level such that, when operating with the second sensitivity level, the occupant needs to move closer to an edge of the person support apparatus to trigger the exit alert than the occupant needs to move to trigger the exit alert when operating with the first sensitivity level.
In some embodiments, the exit detection system is adapted, when in the armed state, to calculate a center of gravity of the occupant, to compare the calculated center of gravity of the occupant to a boundary of a zone, and to issue the exit alert if the calculated center of gravity its outside of the boundary of the zone, and the controller is further adapted to change the operation of the exit detection system in the first manner by changing at least one of a size, shape, or position of the zone.
In some embodiments, the controller is adapted to change the operation of the exit detection system in the first manner by adjusting the calculated center of gravity in a manner that compensates for changes in the signals of the force sensors that are due to contact with the obstruction.
In some embodiments, the person support apparatus includes at least first and second obstruction sensors that are adapted to detect when different portions of the litter frame contact the obstruction during movement of the litter frame. In such embodiments, the controller may be adapted to automatically change operation of the exit detection system in a second manner different from the first manner in response to the second obstruction sensor detecting contact with the obstruction when the exit detection system is in the armed state.
Before the various embodiments disclose herein are explained in detail, it is to be understood that the claims are not to be limited to the details of operation or to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The embodiments described herein are capable of being practiced or being carried out in alternative ways not expressly disclosed herein. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof is meant to encompass the items listed thereafter and equivalents thereof as well as additional items and equivalents thereof. Further, enumeration may be used in the description of various embodiments. Unless otherwise expressly stated, the use of enumeration should not be construed as limiting the claims to any specific order or number of components. Nor should the use of enumeration be construed as excluding from the scope of the claims any additional steps or components that might be combined with or into the enumerated steps or components.
An illustrative person support apparatus 20 that may incorporate one or more aspects of the present disclosure is shown in
In general, person support apparatus 20 includes a base 22 having a plurality of wheels 24, a pair of lifts 26 supported on the base, a litter frame 28 supported on the lifts 26, and a support deck 30 supported on the litter frame 28. Person support apparatus 20 further includes a headboard (not shown), a footboard 34, and a plurality of siderails 36. Siderails 36 are all shown in a raised position in
Lifts 26 are adapted to raise and lower litter frame 28 with respect to base 22. Lifts 26 may be hydraulic actuators, electric actuators, or any other suitable device for raising and lowering litter frame 28 with respect to base 22. In the illustrated embodiment of
Litter frame 28 provides a structure for supporting support deck 30, the headboard (not shown), footboard 34, and siderails 36. Support deck 30 provides a support surface for a mattress (not shown in
Support deck 30 is, in the embodiment shown in
In some alternative embodiments, person support apparatus 20 is constructed with load cells positioned in locations other than litter frame 28. For example, in at least one alternative embodiment, the person support apparatus is constructed with base frame load cells resting on a wheel frame having a construction of the type disclosed in commonly assigned U.S. patent application Ser. 16/917,004 filed Jun. 30, 2020, by Sukumaran et al and entitled PERSON SUPPORT APPARATUS WITH ADJUSTABLE EXIT DETECTION ZONES, the complete disclosure of which is herein incorporated by reference in its entirety. When a person support apparatus is constructed with the base and wheel frame construction of the type disclosed in this application, the load cells may be positioned on the wheel frame such that the entire weight of the base frame is supported on the load cells. Still other manners of positioning the load cells within the person support apparatus, and/or other locations for the load cells, may be utilized.
Further, as disclosed in the '004 application, person support apparatus 20 can include features for extending the width of its support deck 30 to accommodate patients of varying sizes. The width may be adjusted in any increments, for example between a first or minimum width, a second or intermediate width, and a third or expanded/maximum width. The exit detection system of the present disclosure may be configured to make automatic adjustments in response to the width adjustment features of the '004 application so that the width adjustments do not trigger a false occupant exit alert.
As shown in
As shown in
Exit detection system 56 is adapted to determine when an occupant, such as, but not limited to, a patient, of person support apparatus 20 is likely to exit person support apparatus 20. More specifically, exit detection system 56 is adapted to determine when an occupant is likely to leave prior to the occupant actually leaving, and to issue an alert and/or notification to appropriate personnel so that proper steps can be taken in response to the occupant's imminent departure in a timely fashion. The particular structural details of exit detection system 56 can vary widely. It will be understood by those skilled in the art that components of exit detection system 56 may be added or omitted from one or more of the embodiments of exit detection system 56 that are discussed herein.
In the embodiment shown in
Force sensors 60 are adapted to detect downward forces exerted by an occupant of support deck 30. Thus, when an occupant is positioned on support deck 30 and substantially still (i.e. not moving in a manner involving accelerations that cause forces to be exerted against support deck 30), force sensors 60 will detect the weight of the occupant (as well as the weight of any components of person support apparatus 20 that are supported—directly or indirectly—by force sensors 60). In at least one embodiment, force sensors 60 are the same as, and positioned in the same locations as, load cells 54, as shown in
Obstruction sensors 61, 161 are adapted to detect the presence of an obstruction (e.g., chair rail, shelf, window ledge, equipment, etc.) in contact with the person support apparatus. An obstruction can be anything that impedes or prevent passage or progress of the person support apparatus or a portion thereof. In a hospital environment, some typical obstructions that can be encountered include medical equipment, patient personal items, furniture, and fixtures. Obstructions are generically represented by reference numeral 57 throughout the drawings and it will be understood by a person of ordinary skill in the art that the shape, size, and other characteristics of obstructions can vary because an obstruction can be essentially any object foreign to the person support apparatus. It will also be understood that the terms “obstruction” and “obstacle” are used synonymously herein.
That is, an obstruction can be essentially any tangible thing that is fixed or moveable with respect to the person support apparatus that the person support apparatus (or portion thereof) becomes obstructed by through movement of the person support apparatus (or portion thereof), movement of the obstruction, or a combination of movement of the person support apparatus and the obstruction. When an obstruction is encountered by the person support apparatus, one or more of the obstruction sensors 61, 161 will detect the obstruction. Details of obstruction sensors 61 and 161 are provided below with respect to
Obstruction sensors 61, 161 can be installed at various locations about the person support apparatus, not just the locations illustrated and described in connection with
In some embodiments, some or all of the obstruction sensors can take the form of one or more actuator control systems. That is, in some embodiments, obstruction detection can be achieved or complemented by configuration of a controller to monitor current draw and/or overcurrent conditions of the lifts 26 or other actuator system(s) (e.g. Fowler, knee, and foot actuators) on the person support apparatus 20. By monitoring current draw of the lifts 26, the controller 58 can interpolate and detect obstruction conditions. For example, when raising the litter frame 28, if the litter frame encounters an obstruction the current draw for that respective actuator will begin to spike and eventually exceed normal current draw limits relative to load. Accordingly, the controller 58 can identify an obstruction has been encountered and can react accordingly, as discussed in more detail in connection with the control system. One person support apparatus implementing this form of obstruction detection is described in U.S. Pat. No. 10,206,834, filed Dec. 2, 2015, issued to Furman et al. and entitled OBSTRUCTION DETECTION SYSTEM AND METHOD, which is herein incorporated by reference in its entirety.
Pivot sensor 66a, in one embodiment, detects a pivot angle between head section 42 and a plane generally defined by litter frame 28. In some embodiments, pivot sensor 66a does not directly measure this pivot angle, but instead indirectly measures angle 70 by measuring the angle of another component of person support apparatus 20 whose angular orientation has a known relationship with this angle, or by measuring the position of another component of person support apparatus 20 whose position has a known relationship with this angle.
Each siderail sensor 66b is adapted to detect whether the siderail 36 it is associated with is in an up position or a down position. In some embodiments, siderails 36 are also movable to one or more intermediate positions. In those embodiments, siderails sensors 66b can be adapted to detect if their associated siderail 36 is in an intermediate position. In the embodiment of person support apparatus 20 shown in
Siderail sensors 66b can act as obstacle sensors in some embodiments. For example, in embodiments where the siderails are electrically actuated, the current draw and/or overcurrent associated with the actuator system for the siderails can be monitored and act as siderail sensors 66b. That is, an expected electrical signal output can be monitored for the various positions or for an expected transition between the up and down siderail position. Where current draw does not meet a predetermined baseline or other expectation, or an overcurrent or other pattern of current draw can complement or be deterministic of an obstruction detection. Further, even in non-electrical embodiments where the siderail sensors can sense movement between two or more positions, an obstruction may be sensed by transition from an up (or down) siderail state being initiated but the siderail never reaching the target state.
Alternatively, or in addition to siderail sensors 66b, each siderail 36 may include one or more obstruction sensors 61, 161. For example, one or more obstruction switches similar to the obstruction sensors described in connection with
Tilt sensor 66c detects a tilt angle 72 of litter frame 28 with respect to horizontal. In one embodiment, tilt sensor 66c measures this angle directly. In other embodiments, tilt sensor 66c comprises two sensors that detect the distance which each of lifts 26 are extended and circuitry that calculates the tilt angle of litter frame 28 with respect to horizontal from these two distances. In still other embodiments, tilt sensors 66c takes on other forms. One or more additional tilt angle sensors may also be included that measure a tilt angle of litter frame 28 that changes as a result of tilting about a longitudinal axis of person support apparatus 20 (i.e. a first side of litter frame 28 changes its height with respect to the second side).
The tilt sensor 66c can act as an obstacle sensor in some embodiments. In such embodiments, tilt sensor 66c can indicate an obstruction has been encountered by litter frame 28 if the reported angle from tilt sensor 66c differs from what would be expected for litter frame 28 (as determined, for example, by the commanded extensions of lifts 26). In other words, control system 43 can compute the expected tilt angle of litter frame 28 from the commands that it gives to lifts 26, compare that expected angle to the angle reported from tilt sensor 66c, and conclude that an obstruction has been detected if the expected angle differs from the reported angle by more than a threshold.
Turn sensor 66d detects a turn angle of a turning mechanism, such as a powered mattress having one or more inflatable turning bladders (not shown), that is used to turn an occupant of person support apparatus 20. Turn sensor 66d is, in at least one embodiment, positioned inside of the mattress (not shown) and measures turn angle directly. In other embodiments, turn sensor 66d measures one or more inflation pressures of one or more bladders inside of the mattress and estimates turn angle based upon the one or more measured inflation pressures.
Height sensor 66e detects either an absolute or relative height of litter frame 28. More specifically, in one embodiment, height sensor 66e detects how far each lift 26 has extended from its lowest position. In another embodiment, height sensor 66e detects how high one or more points on litter frame 28 (or any component of person support apparatus 20 non-movably coupled to litter frame 28) is with respect to a reference (e.g. a floor, base 22, etc.).
Position sensor 66f detects the longitudinal position of support deck 30 relative to litter frame 28. That is, as noted previously, support deck 30 is longitudinally movable, in some embodiments, with respect to litter frame 28. In some embodiments, person support apparatus 20 is constructed such that the longitudinal position of support deck 30 relative to litter frame 28 is directly correlated to a pivot angle of the head section 42. In such embodiments, position sensor 66f and pivot angle sensor 66a may be one and the same. In still other embodiments, person support apparatus 20 may be constructed such that the longitudinal position of support deck 30 relative to litter frame 28 is directly correlated to the position and/or orientation of some other component of person support apparatus, in which case position sensor 66f may be configured to measure the position of support deck 30 indirectly by measuring the position or orientation of the other component. In other embodiments, support deck 30 may be positioned at a longitudinally and laterally fixed location with respect to litter frame 28, and position sensor 66f may be omitted.
All of the sensors 66 are in communication with controller 58 (
Controller 58 is also in communication with user interface 62. User interface 62 is implemented in the embodiment shown in
In one embodiment, user interface 62 includes a control that enables a user to arm and disarm exit detection system 56, as well as allowing a user to select different sensitivity levels which are used for triggering an exit alert, as will be discussed in greater detail below. In at least some embodiments, the controls also allow a user to configure the alerting features of exit detection system 56, including choosing from amongst the different types of alerts that can be issued by exit detection system 56. Such types include local alerts (issued at person support apparatus 20), remote alerts (issued at a remote location, such as a nurse's station, hallway light, or to mobile communication devices carried by personnel), audio alerts, visual alerts, and/or any combinations of these. The user interface can also include a variety of options with regard to configuration of the obstruction detection features including both the associated alerting features as well as other reactions to the detection of an obstruction, such as how other systems react to obstruction detection. In some embodiments, the exit detection system 56 is configurable to react to obstruction detection in a variety of different ways. The reactions can be configured for all obstruction detection or based on a region, area, or particular sensor or set of obstruction sensors.
In some embodiments, controller 58 of exit detection system 56 is adapted to determine the center of gravity of whatever load is applied to force sensors 60, compare that center of gravity to a zone, and issue an exit alert if the center of gravity moves outside of that zone. In other words, exit detection system 56 determines the center of gravity of the combined weight of an occupant, mattress, and/or any objects that are positioned on support deck 30 or litter frame 28, as well as those components of person support apparatus 20 whose weight is supported by force sensors 60 (e.g. litter frame 28, support deck 30, siderails 36, etc.) and compares it to an area of acceptable locations (i.e. a zone). If the center of gravity is not within than zone, this is indicative of the patient exiting, and an exit alert is issued. In one embodiment, exit detection system 56 determines this center of gravity using the system and method disclosed in commonly assigned U.S. Pat. No. 5,276,432 issued to Travis entitled PATIENT EXIT DETECTION MECHANISM FOR HOSPITAL BED, the complete disclosure of which is incorporated herein by reference in its entirety. In other embodiments, other algorithms may be used.
In some embodiments, exit detection system 56 is configured to distinguish between detected changes in the center of gravity of the load that are due to the occupant moving with respect to the support surface and changes in the detected center of gravity of the load that are due to movement of one or more components of the person support apparatus. Such movement includes, but is not limited to, pivoting of one or more sections of deck 30; tilting of litter frame 28; longitudinal movement of support deck 30 relative to litter frame 28; movement of one or more siderails 36 from an up position to a down positions, or vice versa; changes in height of litter frame 28; and/or therapeutic turning of the occupant by a turning device built into the mattress or otherwise positioned on top of support deck 30. Stated alternatively, in such embodiments, exit detection system 56 is configured to determine how much, if any, of the changes in the outputs of force sensors 60 is due to patient movement relative to support surface 31 and how much, if any, of the changes in the outputs of force sensors 60 is due to components of person support apparatus having moved. Exit detection system 56 may then compensate the readings it obtains from force sensors 60 in order to account for the changes that are due to components of person support apparatus 20 having moved. Manners in which this compensation may be applied are disclosed in U.S. patent publication 2020/0214599 to Kostic entitled EXIT DETECTION SYSTEM WITH COMPENSATION, the complete disclosure of which is incorporated herein by reference in its entirety.
Exit detection system 56, in at least one embodiment, is configured to distinguish between detected changes in the center of gravity of the load that are due to the occupant moving with respect to the support deck 30 and changes in the detected center of gravity of the load that are due to obstructions encountered by the person support apparatus. If an obstruction exerts a force on litter frame 28 or portion thereof (or any components, or portions thereof, supported by the litter frame) it will change the detected center of gravity of the load because that force, or a component of that force, will be detected by the load cells and will introduce an error into the calculation of the patient's center of gravity. As will be discussed in greater detail below, this error may be addressed in different manners, such as, but not necessarily limited to, removing this error from the center of gravity calculations and/or changing a size, shape, and/or location of an exit detection alert zone in a manner that addresses this error.
The changes in the center of gravity that are detected by exit detection system 56 as a result of an obstruction being impacted can vary. Generally speaking, exit detection system 56 is configured to detect changes in the center of gravity due to pivoting of one or more sections of deck 30 into an obstruction; tilting of litter frame 28 into an obstruction; longitudinal movement of support deck 30 relative to litter frame 28 such that an obstruction encounters the litter frame 28 or a component thereof; movement of one or more siderails 36 from an up position to a down positions such that an obstruction exerts an upward or downward force component on one or more of the siderails (or vice versa); and/or changes in height of litter frame 28 that cause the litter frame to experience an upward or downward force component from an obstacle. The exit detection system can also be configured to detect changes in the center of gravity due to movement of one or more obstructions with respect to the person support apparatus or a component thereof (i.e. an obstruction is moved into contact with person support apparatus 20, rather than person support apparatus moves into contact with an obstruction).
Control system 43 also includes a nurse call interface 67 and a network transceiver 73. Nurse call interface 67 is adapted to communicatively couple to a conventional nurse call system so that controller 58 is able to communicate information to the nurse call system, such as, but not limited to, an exit alert. In many instances, nurse call interface 67 is adapted to communicate information to the nurse call system by opening or closing one or more relays that are electrically coupled to pins of a 37-pin wall outlet positioned on the headwall of a typical hospital room. Further details about different embodiments of nurse call interface 67 are provided below.
Network transceiver 73 may be a wireless transceiver adapted to communicate with one or more wireless access points of the healthcare facility's local area network. In some embodiments, transceiver 73 may be a WiFi transceiver adapted to transmit and receive wireless electrical signals using any of the various WiFi protocols (IEEE 802.11, 801.11g, 802.11n, 802.11ac . . . , etc.). In other embodiments, network transceiver 73 may be a transceiver adapted to communicate using any of the frequencies, protocols, and/or standards disclosed in commonly assigned U.S. patent application Ser. No. 62/430,500 filed Dec. 6, 2016, by inventor Michael Hayes and entitled NETWORK COMMUNICATION FOR PATIENT SUPPORT APPARATUSES, the complete disclosure of which is incorporated herein by reference. In still other embodiments, transceiver 73 may be a wired transceiver that communicates with the healthcare facility local network over a wired connection, such as an Ethernet cable or the like. Regardless of whether transceiver 73 is a wired or wireless transceiver, it enables controller 58 to communicate with one or more servers on the healthcare facility's computer network.
Switch 55 is installed toward the bottom of the footboard 34 such that the plunger of the switch juts through an aperture in the litter frame 28 past the plane of the bottom of the footboard 34.
When an obstruction 57 forces the switch plate 53 upward, the switch plate pivots to a substantially flat orientation (
Because of the construction illustrated in
In the current embodiment, the switch 55 provides a single output signal indicative of whether an obstruction is present or absent. The switch is configured to activate in response to force at or above a predetermined force threshold being applied to the plunger, which causes the switch to generate a single output. Accordingly, a single output signal can be provided that is indicative of whether an obstruction is present without having to compare multiple sensor signals. In alternative embodiments, the switch 55 can provide one or more output signals, including non-binary output signals such as values indicative of various characteristics of the switch (e.g. the obstruction detection signal being indicative of an amount of travel of the plunger, a plunger position, an operating force, a total travel force, an amount of displacement or other characteristic). It will be well understood by those of skill in the art, the dimensions and other mechanical characteristics along with operating characteristics of the switch 55 can vary along with its circuitry depending on the application. In the current embodiment, the switch 55 is a plunger style miniature door switch with a 9 mm long stroke. The switch can be implemented in a double throw, normally closed, normally open, or other configuration.
The illustrated embodiment of
One example of an alternative obstruction detector 161 is shown in more detail in
A vacuum formed floating belly pan or cover 63 acts as an actuating barrier for the obstructions and subsequent activation of the underlying obstruction switches 65. The four switches 65 mounted near the outermost corner locations of the mounting plate 69 are covered by the belly pan 63 which also covers the hinged electrical plates 69 under the litter frame 28, perhaps as best shown in
The floating cover 63, shown in
Depending on the size and position of the obstruction, some, but not all of the obstruction switches 65 may or may not be activated contemporaneously. That is, the obstacle may be encountered toward one of the corners such that only one lever switch is thrown when the belly pan 63 is forced upwards. This is due to the floating configuration of the belly pan. The controller can be configured to infer obstruction position and/or other information about the obstruction based on which switches activate. That is, the controller can be configured to associate the obstruction switch 65 outputs with physical areas of the person support apparatus. Thus, information about where an obstacle is encountered can be inferred by which switches are activated and which are not. For example, if a single obstruction switch is triggered without any other switches being triggered, the position of the obstruction can be inferred to be the area associated with the position of the switch that triggered. Or, if two or more obstruction switches are triggered the position of the obstruction can be inferred to be the collective areas associated with the positions of the triggered switches. This information can be utilized to alert staff regarding the obstacle encounter. The information can also be utilized for performing targeted maintenance and repair on the person support apparatus.
Further, the controller can be configured to infer movement information about the encounter based on activation timing (e.g. timestamps) of the obstruction switches. That is, the order in which the switches activate is generally indicative of the movement associated with the encounter. When the activation timing of the obstruction switches is combined with movement data of the person support apparatus (e.g. actuation of the lift system), the controller can be configured to determine additional information about the cause of the obstruction encounter, which can be logged and/or otherwise provided to an operator of the person support apparatus or other personnel.
Exit detection system 56 is configured to cooperate with the obstruction detection sensors 61 and/or 161. That is, exit detection system 56 is configured to utilize the outputs from one or more obstruction detectors 61, 161 and change its operation in one or more manners in response to an obstruction being detected, and in some cases, in response to the obstruction no longer being detected. In some embodiments, exit detection system 56 is configured to react to the detection of an obstruction in one of three different manners: (1) by automatically disarming (if previously armed) the exit detection system in response to an obstruction being detected; (2) by automatically triggering an exit alert in response to an obstruction being detected; or (3) by automatically adjusting the calculations used for determining whether to issue an exit alert, wherein the adjustment attempts to account for, and thus remove, the changes in the outputs of the load cells that are due to the contact with the obstruction and that otherwise create errors in the calculated patient's center of gravity. Each of these three different manners of reacting are described in more detail with respect to algorithms 1200, 1300, and 1400 of
In the embodiment shown in
If no obstruction is present, the system proceeds to calculate an initial center of gravity of the occupant of person support apparatus 20. This calculation is performed using known mathematical techniques for computing a center of gravity, as well as knowledge of the relative positions of the force sensors 60. Although other coordinate systems may be used, controller 58 computes the center of gravity using a planar coordinate system 86 (
After determining the occupant's center of gravity at step 1206, controller 58 proceeds to step 1208 where it determines the initial value of one or more parameters of person support apparatus 20. More specifically, in the embodiment illustrated in
After completing step 1208, controller 58 moves onto step 1210 (
If no obstruction is present, controller 58 proceeds to step 1216 (
If none of these values have changed since the values were initially taken at step 1208, controller 58 proceeds to step 1210, described above. If controller 58 determines at step 1216 that one or more of the initial values (from step 1208) have changed, it proceeds to a step 1218, where it determines one or more compensation factors that correspond to the changed values. That is, for every value that has changed, controller 58 computes a compensation factor at step 1218. Thus, for example, if pivot angle 70 and height 78 are both different at step 1218 than they were initially at step 1208, controller 58 computes a pivot angle compensation factor and a height compensation factor. In general, controller 58 calculates at step 1218 one or more compensation factors that provide an estimate of how much the center of gravity reading taken at step 1218 has been influenced by factors other than the occupant moving relative to support deck 30.
Once compensation factors are calculated, the controller 58 can proceed to step 1220 where it applies the compensation factor(s) to the center of gravity computed at step 1206. The result is a center of gravity calculation that has substantially eliminated changes in the center of gravity due to movement of one or more components of person support apparatus 20, or other effects that are not the result of the occupant changing his or her weight distribution relative to support deck 30 or support surface 31. Consequently, the compensated center of gravity calculation made at step 1220 corresponds substantially to the occupant's center of gravity. Controller 58 then proceeds to step 1210 where it determines whether the occupant's center of gravity (i.e. the compensated center of gravity calculated at step 1220) is inside or outside of the zone that defines the exit alert conditions. If it is outside the zone, an alert is issued at step 1226. If it inside the zone, no alert is issued and—to the extent exit detection system 56 has not been shut off—control returns to step 1212 where the system checks whether an obstruction has been encountered. The manner in which controller 58 determines and applies the compensation factors at steps 1216, 1218, and 1220 may be carried out in the manners disclosed in commonly assigned U.S. patent publication 2020/0214599 filed by Kostic et al. and entitled EXIT DETECTION SYSTEM WITH COMPENSATION, the complete disclosure of which is incorporated herein by reference in its entirety. Alternatively, controller 58 may be modified to not calculate and/or apply any of the compensation factors of steps 1216, 1218, and 1220, but instead skip these steps.
It will be understood that, although not illustrated in
It will also be understood that algorithm 1200 may be modified to automatically send a message via network transceiver 73 to a server coupled to the healthcare facility's local area network as part of step 1224. The message indicates that exit detection system 56 has been disarmed. Thus, in addition to disarming exit detection system 56 in response to detecting an obstacle, controller 58 may be configured to automatically send a message notifying a remote server that it has automatically disarmed the exit detection system 56. Still further, if controller 58 is configured to automatically re-arm exit detection system 56 when the obstacle is no longer detected, controller 58 may be further configured to automatically send a message to the server via network transceiver 73 indicating that exit detection system 56 has been re-armed. The server that receives these messages may be a server that executes a caregiver assistance application of the type disclosed in commonly assigned PCT patent application PCT/US2020/039587 filed Jun. 25, 2020, and entitled CAREGIVER ASSISTANCE SYSTEM, the complete disclosure of which is incorporated herein by reference.
In an alternative embodiment, instead of automatically deactivating (i.e. disarming) exit detection system 56 in response to an obstacle being detected, the exit detection system 56 can be configured to automatically issue an exit detection alert in response to detecting contact with an obstacle. One example of such an embodiment is shown in
In some modified embodiments, algorithm 1300 may be modified to omit step 1322 and skip directly from step 1304 to step 1326 when an obstacle is detected. In such modified embodiments, controller 58 does not issue a separate obstruction alert when an obstruction is detected and exit detection system 56 is armed, but instead only issues an exit alert. Further, in such modified embodiments, if exit detection system 56 is not armed and obstruction detection sensor 61 detects contact with an obstruction, controller 58 is configured to issue an obstruction detection alert. Thus, in such embodiments, controller 58 is configured to issue an exit detection alert when exit detection system 56 is armed and an obstruction is contacted, and to issue an obstruction alert when exit detection system 56 is disarmed and an obstruction is contacted.
It will be understood that the difference between an exit alert and an obstruction alert may take on a variety of different forms. In general, an exit alert will always be communicated to a nurse call system of the healthcare facility via the nurse call interface 67 that is built into person support apparatus 20. When nurse call interface 67 is coupled to the nurse call system via a cable, the communication of the exit alert to the nurse call system typically takes place by opening or closing one or more relays within nurse call interface 67 that are in electrical communication with corresponding pins of a nurse call outlet built into a headwall of the healthcare facility. When nurse call interface 67 is coupled to the nurse call system via wireless communication, the communication of the exit alert to the nurse call system may take place by sending a wireless signal to a wall mounted headwall module that, in response, opens or closes one or more relays that are in electrical communication with the pins of the nurse call outlet. Further details of the manners in which the nurse call interface 67 may communicate an exit alert to the nurse call system, whether via a cable or wirelessly, are disclosed in the following commonly assigned U.S. patent applications: Ser. No. 62/896,075 filed Sep. 5, 2019 by Alexander Bodurka et al. and entitled PATIENT SUPPORT APPARATUSES WITH NURSE CALL CONNECTION DETECTION; Ser. No. 15/945,437 filed Apr. 4, 2018, by inventors Krishna Bhimavarapu et al. and entitled PATIENT SUPPORT APPARATUSES WITH RECONFIGURABLE COMMUNICATION; Ser. No. 14/819,844 filed Aug. 6, 2015, by inventors Krishna Bhimavarapu et al. and entitled PATIENT SUPPORT APPARATUSES WITH WIRELESS HEADWALL COMMUNICATION; Ser. No. 16/215,911 filed Dec. 11, 2018, by inventors Alexander Bodurka et al. and entitled HOSPITAL HEADWALL COMMUNICATION SYSTEM; Ser. No. 62/833,943 filed Apr. 15, 2019, by inventors Alexander Bodurka et al. and entitled PATIENT SUPPORT APPARATUSES WITH NURSE CALL AUDIO MANAGEMENT; Ser. No. 16/215,911 filed Dec. 11, 2018, by inventors Alexander Bodurka et al. and entitled HOSPITAL HEADWALL COMMUNICATION SYSTEM; Ser. No. 16/217,203 filed Dec. 12, 2018, by inventor Alexander Bodurka, and entitled SMART HOSPITAL HEADWALL SYSTEM; and Ser. No. 16/193,150 filed Nov. 16, 2018, by inventors Alexander Bodurka et al. and entitled PATIENT SUPPORT APPARATUSES WITH LOCATION/MOVEMENT DETECTION, the complete disclosures of all of which are incorporated herein by reference.
In some embodiments of person support apparatus 20, the exit alert is also communicated wirelessly via a separate communication channel to one or more servers. In such embodiments, controller 58 is configured to utilize network transceiver 73 to transmit a notification to a server on the local area network of the healthcare facility. This notification indicates that an exit alert has been issued. In some embodiments, the server may forward this notification to one or more portable electronic devices carried by one or more caregivers associated with the healthcare facility. Alternatively, or additionally, the exit detection alert may be forwarded to one or more servers that are located remotely from the healthcare facility and that are not part of the healthcare facility's local area network. Such forwarding may take place over an Internet gateway, router, or other conventional network appliance that communicatively couples the local area network to the Internet.
In some embodiments, the obstruction detection alert is only a local alert that involves one or more of a sound or light emitted from person support apparatus 20. Additionally, such localized alerting may involve displaying a message on an electronic display of person support apparatus. The message may indicate that an obstruction was detected. In some embodiments, controller 58 may also be configured to send a notification message to a server on the healthcare facility's network indicating that an obstruction was detected. This obstruction notification message may be forwarded to one or more other servers and/or one or more portable electronic devices carried by one or more caregivers. The obstruction alert is not issued through the nurse call interface 67 because conventional nurse call outlets do not include a pin (or set of pins) that are able to communicate this information. However, if person support apparatus 20 is coupled to a nurse call system that is capable of communicating this information, controller 58 may be configured to also send the obstruction alert through nurse call interface 67.
In those embodiments where controller 58 transmits the obstruction alert and/or the exit alert via network transceiver 73 to a server of the local area network, the server may be a server the executes a caregiver assistance application of the type disclosed in commonly assigned PCT patent application PCT/US2020/039587 filed Jun. 25, 2020, and entitled CAREGIVER ASSISTANCE SYSTEM, the complete disclosure of which is incorporated herein by reference. In such embodiments, the caregiver assistance system may then forward the exit alert and/or obstruction detection alert to designated portable electronic devices (and/or stationary electronic devices) so that caregivers associated with those devices are apprised of the obstruction detection and/or the exit alert.
In some embodiments of person support apparatus 20, controller 58 is configured to send an exit alert message to a remote server via network transceiver 73 when an obstruction is detected, but to include information within the notification message indicating that the exit alert is due to an obstruction being detected, not due to the occupant exiting from person support apparatus 20. In this manner, any messages forwarded by the server to portable electronic devices carried by healthcare personnel will be informed that the exit alert is being caused, not by an occupant exit, but rather by an obstruction that was encountered.
Returning to
It will be understood that, although not illustrated in
In other embodiments, the exit detection system 56 is configured to react to obstruction detection by compensating for the errors introduced into the load cell readings by the obstruction so that the bed exit system can continue to operate in an accurate manner despite the obstruction. In an example of one such exit detection system, controller 58 is configured to execute an exit detection algorithm 1400 as illustrated in
From step 1422, controller 58 proceeds to step 1430 where it makes adjustments to the operation of exit detection system 56 that are designed to account for the force components detected by force sensors 60 that are due to contact with the obstacle. In other words, at step 1430, controller 58 makes adjustments to the operation of exit detection system 56 that are designed to either remove or accommodate the errors introduced into the calculation of the occupant's center of gravity that are due to the obstruction exerting forces on one or more of the force sensors 60. As will be discussed in greater detail below, controller 58 may be configured to implement step 1430 in a variety of different manners.
In a first manner, which is illustrated in more detail in
Turning to the first manner by which controller 58 may adjust the operation of exit detection system 56 at step 1430 of algorithm 1400 (
Once the two sets of readings are identified, controller 58 determines the difference between the two, such as by determining the average of the first set, determining the average of the second set, and then subtracting one from the other. Other processing may also or alternatively be used in order to compute the general difference between the first and second sets of readings. The purpose of the two sets of readings is to capture the difference in the outputs of the force sensors immediately prior to the obstruction detection and immediately after the obstruction detection. This difference is presumed to be due to the obstruction.
When calculating this difference, it will be understood that controller 58 does this for each load cell (force sensor 60). That is, controller 58 identifies a first set of readings for the right head end load cell that were captured immediately before the obstruction was detected and identifies a second set of readings for the right head end load cell that were taken by the right head end load cell immediately after the obstruction was detected. The difference between these two sets is then determined and stored as a right head end load cell adjustment factor. This same process is repeated for the other load cells: the left head end load cell, the right foot end load cell, and the left foot end load cell. The result is the generation of four load cell adjustment factors—one for each of the four load cells. Controller 58 then applies each of these load cell adjustment factors to the outputs from each of the corresponding load cell readings that are taken after the obstruction is detected (and continues to apply these adjustment factors until the obstruction is no longer detected—at which point is stops applying these adjustment factors). This process is better explained with reference to
As shown in
Thus, for example, if the readings from the four load cells immediately before an obstruction is encountered (or an average of multiple readings taken immediately before the obstruction is detected) are 25, 30, 37, and 22 pounds, and the readings from these same four load cells (or an average of multiple readings) taken after the obstruction is detected are 20, 25, 40, and 25, respectively, controller 58 will compute the following four differences: (1) −5.0 (20−25); (2) −5.0 (25−30); (3) 3.0 (40−37); and (4) 3.0 (25−22). As a result, controller 58 will, in at least one embodiment, add five pounds to all subsequent readings of the first and second load cells and subtract three pounds from all subsequent readings from the third and fourth load cells. The result will be that the subsequently calculated center of gravities will have the changes in the force readings that occurred between the first and second sets of load cell readings (i.e. during the time of the impact with the obstruction) removed from the subsequent calculations. The subsequently calculated center of gravities will therefore be a more accurate reflection of the occupant's actual center of gravity on person support apparatus 20. As noted, the subtraction of these compensation values from each of the load cells (e.g. −5.0, −5.0, 3.0, and 3.0) will continue until the obstruction is no longer detected.
As was noted above in the discussion of step 1430 of algorithm 1400 (
As was described previously, controller 58 uses alert zone 98 (or 198) to compare the currently calculated center of gravity of the occupant. If the current center of gravity of the occupant travels outside the boundaries of alert zone 98 (or 198) while the exit detection system 56 is armed, controller 58 issues an exit alert.
Returning to
In the embodiment of
In some embodiments, such as the one shown in
In some alternative embodiments (not shown), controller 58 may be configured to make the same changes to the size, shape, and/or location of alert zone 98 regardless of the amount of force that is offloaded from load cells 54 to obstruction 57. That is, regardless of whether or not litter frame 28 exerts, say, ten pounds of force onto obstruction 57 or twenty pounds, controller 58 is configured to change the size, shape, and/or location of alert zone 98 in the same manner for these differing amounts of force. In some of these alternative embodiments, controller 58 may be configured to automatically switch to using a different alert zone 98 having a different sensitivity in response to the detection of an obstacle. For example, in some embodiments of exit detection system 56, a user is able to select a different sensitivity level, which may correspond to the general size of a zone 98. In such embodiments, controller 58 may be configured to automatically switch to using, for example, the zone 98 with the least sensitivity in response to detecting an obstruction.
In still other embodiments, controller 58 may be configured to automatically switch to using a non-zone based exit detection algorithm in response to the detection of an obstruction. For example, in at least one embodiment, controller 58 is configured to stop comparing a calculated center of gravity to an alert zone in response to the detection of an obstacle, and instead to look for a drop in total weight detected on litter frame 28 of more than a predefined threshold (which may be expressed in absolute terms (e.g. pounds), or as a percentage of the total current weight or as a percentage of the occupant's weight). In any of the aforementioned embodiments, when the obstacle is no longer detected, controller 58 may be configured to automatically switch back to using the algorithm and/or zone it was using prior to contact with the obstacle (and/or switch back to not using a compensation factor).
In those embodiments of person support apparatus 20 that include multiple obstruction sensors 61, 161, controller 58 may be configured to react in different manners depending upon which obstruction sensor 61, 161 detects contact with an obstruction 57. For example, in some embodiments, if a first obstruction sensor 61 positioned toward the foot end of litter frame 28 detects contact with an obstruction 57 as the litter frame is lowered onto the obstruction 57, controller 58 may be configured to adjust the size, shape, and/or position of the alert zone 98 in a manner that at least partially shifts the zone 98 toward head end 38. As noted, this adjustment may take into account the magnitude of the off-loaded force, or it may be insensitive to the amount of force off-loaded onto the obstruction. On the other hand, if a second obstruction sensor is positioned at, say, head end 38 of litter frame 28 and this second obstruction sensor detects as obstruction 57 as litter frame 28 is lowered onto the obstruction, controller 58 may be configured to adjust the size, shape, and/or position of the alert zone 98 in a manner that at least partially shifts the zone 98 toward foot end 40. This adjustment may also take into account the magnitude of the off-loaded force, or it may be insensitive to the amount of force off-loaded onto the obstruction. Regardless of whether or not the magnitude of the offloaded force is determined or not, the adjustments to zone 98 may be different, depending upon which one of the first or second obstruction sensors detects contact with the obstruction. The same is true for any other sensors that may be added to person support apparatus 20 beyond the aforementioned first and second obstruction sensors 61, such as one or more obstruction sensors that are positioned along the side(s) of person support apparatus 20 (and which may prompt exit detection system 56 to change the size, shape, and/or location of zone 98 in a lateral manner).
Returning to algorithm 1400 and
It will be understood that, although not illustrated in
It will be understood that in any of the embodiments of exit detection system 56 that utilize any of algorithms 1200, 1300, or 1400 (or other algorithms), exit detection system 56 may be configured to allow a user to select which zone will be used by controller 58 when determining whether to issue an alert or not. That is, exit detection system 56 may include multiple alert zones 98 of different sizes, shapes, and/or locations, and allow the user to select which zone to utilize, thereby allowing the user to select different sensitivity levels for exit detection system 56. In some embodiments, person support apparatus 20 includes three predefined zones and is adapted to allow a user to select which one of these three zones is to be used at a given time via user interface 62. In other embodiments, a different numbers of zones are permitted by exit detection system 56.
It will also be understood that in any of the embodiments of exit detection system 56 that permit the user to select from multiple alert zones 98, controller 58 may be configured to define the different alert zones 98 in different manners. For example, in one embodiment, the zone having the smallest area (in coordinate system 86) has its boundaries defined using the patient's first center of gravity reading taken by exit detection system 56. That is, the smallest zone is centered at whatever location the person's center of gravity is initially located. The zone having the largest area is defined, in at least one embodiment, without regard to the occupant's initial location, but instead has fixed values in coordinate system 86. For example, in one embodiment, the zone with the largest area has its edges located just inwardly from the outer edges of support deck 30. Other manners of defining the zone boundaries may also be used.
Still further, it will also be understood that, in any of the embodiments of exit detection system 56 that utilize any of algorithms 1200, 1300, or 1400 (or other algorithms), exit detection system 56 may be configured to dynamically change the size, shape, and/or location of the alert zones based on factors other than the detection of an obstruction, such as, but not limited to, the movement of one or more components of person support apparatus 20. For example, in at least one embodiment, the shape and/or boundaries of a zone change based upon whether or not a siderail is in the up position or the down position. If a siderail is in an up position, it is less likely that an occupant of person support apparatus 20 will exit therefrom by climbing over that siderail. Accordingly, controller 58 may use, in that situation, a zone that allows the occupant's center of gravity to approach more closely to the up siderail than if the siderail were in a down position before issuing an alarm. If the siderail is moved to a lower position, the zone is switched to include a more restricted boundary—the more restricted boundary representing the fact that, with the siderail lowered, it is easier for an occupant to exit support deck 30 in the area of the lowered siderail. One manner of using siderail sensors to make an adjustment to an alert zone of an exit detection system is disclosed in commonly assigned U.S. Patent Application Publication No. 2017/0098359 to Sidhu et al., entitled PERSON SUPPORT APPARATUS WITH EXIT DETECTION SYSTEMS, the complete disclosure of which is incorporated herein by reference. Several other manners of adjusting the size, shape, and/or location of an alert zone are disclosed in U.S. patent application Ser. No. 16/917,004, filed Jun. 30, 2020 to Sukumaran, entitled PERSON SUPPORT APPARATUS WITH ADJUSTABLE EXIT DETECTION ZONES, which is also herein incorporated by reference in its entirety. In any of the embodiments where exit detection system 56 is configured to dynamically change the size, shape, and/or location of alert zones 98 based on the movement of one or more components, those changes are separate from and in addition to any changes it may make to the size, shape, and/or location of alert zones 98 based on the detection of contact with an obstruction.
Still further, it will also be understood that algorithm 1200, 1300, and/or 1400 may be modified in a number of manners from what is illustrated in
It will also be understood that, although not illustrated in any of
As was noted previously, exit detection system 56 can be modified from the embodiment shown in
As was noted earlier, although
It will also be understood that exit detection system 56 may be modified in still additional manners. For example, in some embodiments, exit detection system 56 may be modified to account for changes in the calculated center of gravity of the occupant that are due to the addition or subtraction of an object from litter frame 28. In such embodiments, controller 58 determines the position of the added or removed object in coordinate frame of reference 86, as well as the weight of the added or removed object, and mathematically calculates a compensation factor that accounts for this added or removed weight. The detection of an added or removed object, as well as the location of its addition or removal, can be accomplished in multiple different manners. In one manner, the addition or removal of an object is detected in the manner disclosed in commonly assigned U.S. patent application Ser. No. 62/065,242 filed Oct. 17, 2014 by inventors Marko N. Kostic et al. and entitled PERSON SUPPORT APPARATUS WITH MOTION MONITORING, the complete disclosure of which is incorporated herein by reference. The detection of an added or removed object may alternatively or additionally be determined by an image detection system such as that disclosed in commonly assigned U.S. patent application Ser. No. 13/242,022 filed Sep. 23, 2011 by inventors Richard Derenne et al. and entitled VIDEO MONITORING SYSTEM, the complete disclosure of which is also incorporated herein by reference. The detection and/or removal of an object can still further be determined by one or more thermal image sensors, such as those disclosed in commonly assigned U.S. patent application Ser. No. 61/989,243 filed May 6, 2014 by inventors Marko N. Kostic et al. and entitled PERSON SUPPORT APPARATUS WITH POSITION MONITORING, the complete disclosure of which is also incorporated herein by reference. Exit detection system 56 can therefore utilize and/or combine any of algorithms 1200, 1300, and/or 1440, or any of their modifications, with any of the features and/or algorithms of the systems disclosed in the aforementioned 62/065,242; 13/232,22; and/or 61/989,243 patent applications.
It will be understood by those skilled in the art that exit detection system 56 may also be modified to calculate an additional correction factor that is applied when force sensors 60 are implemented as load cells that are only capable of detecting vertical forces applied against them. Correction of such load cell readings is accomplished by multiplying the outputs of the load cells by a known trigonometric factor, as described in more detail in column 17, line 25 through column 21, line 30 of commonly assigned U.S. Pat. No. 7,702,481 entitled DIAGNOSTIC AND CONTROL SYSTEM FOR A PATIENT SUPPORT, the complete disclosure of which is also hereby incorporated herein by reference.
It will also be understood that, although exit detection system 56 has been primarily described herein as calculating a center of gravity of the occupant and issuing an alert when that center of gravity extends outside of an alert zone, exit detection system 56 can be configured to operate in manners that do not require the calculation of the occupant's center of gravity. For example, in some embodiments, exit detection system 56 can be configured to examine the ratios of the forces exerted on the head end, foot end, right side, and left side of the litter frame 28 and, if those ratios exceed a threshold, issue an exit alert. For example, if a total weight on litter frame 28 is equal to X, controller 58 may be programmed to issue an alert if more than, say, sixty-percent of X is distributed amongst the two left load cells (or amongst the two right load cells). In this manner, controller 58 doesn't need to explicitly calculate a center of gravity of the occupant, but instead can issue exit alerts when the weight supported on litter frame 28 shifts by more than a threshold amount toward either side (and/or toward head end 38 or foot end 40). In such embodiments, controller 58 can implement steps 1430 and 1434 of algorithm 1400 by changing the threshold that it uses to trigger an exit alert (e.g. instead of, say, sixty percent of the weight being supported on one side, it might use seventy percent). Still other manners of implementing steps 1430 and 1434 are possible.
Various alterations and changes can be made to the above description without departing from the spirit and broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. This disclosure is presented for illustrative purposes and should not be interpreted as an exhaustive description of all embodiments of the invention or to limit the scope of the claims to the specific elements illustrated or described in connection with these embodiments. For example, and without limitation, any individual element(s) of the described invention may be replaced by alternative elements that provide substantially similar functionality or otherwise provide adequate operation. This includes, for example, presently known alternative elements, such as those that might be currently known to one skilled in the art, and alternative elements that may be developed in the future, such as those that one skilled in the art might, upon development, recognize as an alternative. Further, the disclosed embodiments include a plurality of features that are described in concert and that might cooperatively provide a collection of benefits. The present invention is not limited to only those embodiments that include all of these features or that provide all of the stated benefits, except to the extent otherwise expressly set forth in the issued claims. Any reference to claim elements in the singular, for example, using the articles “a,” “an,” “the” or “said,” is not to be construed as limiting the element to the singular.
This application claims priority to U.S. provisional patent application Ser. No. 63/085,523 filed Sep. 30, 2020, by inventors Anish Paul et al. and entitled EXIT DETECTION SYSTEM WITH OBSTRUCTION REACTION, the complete disclosure of which is incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US21/52390 | 9/28/2021 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63085523 | Sep 2020 | US |
