US20110068932A1 - Bed exit alarm of hospital bed mattress - Google Patents

Abstract

A mattress system includes a mattress, a control unit spaced from the mattress, and a connector assembly that pneumatically and electrically interconnects the control unit with the mattress. The control unit has a main housing and a plurality of user interface modules that are selectively coupleable to the control unit and that are programmed differently to provide different modes of operation for the mattress system. A pressure sensor inside the mattress detects the presence or absence of a person on the mattress. The mattress system has a bed exit alarm system that, when armed, provides a bed exit alarm if the pressure sensor in the mattress detects that a patient has exited the mattress. The connector assembly includes a dual mode connector having both electrical and pneumatic couplers and a dual lumen hose assembly that extends from the dual mode connector to the mattress.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is a divisional of U.S. application Ser. No. 11/559,529, filed Nov. 14, 2006, which issued as U.S. Pat. No. 7,849,545 on Dec. 14, 2010 and which is hereby incorporated by reference herein.
BACKGROUND OF THE INVENTION
• The present disclosure relates to hospital bed mattresses and particularly, to control systems for hospital bed mattresses in which portions of the control systems may control inflation of one or more air bladders included in the mattresses and portions of the control systems may control bed exit alarms. The present disclosure also relates to hose assemblies that interconnect control units with associated mattresses.
• Hospitals use a variety of different mattress types to support patients having different medical needs. Some patients benefit from being supported on alternating pressure mattresses or rotation therapy mattress. Other patients may not need to be supported on these types of mattresses having dynamic therapies, but rather, so-called static air mattresses that simply operate to provide a relatively low interface pressure may be suitable for such patients. To address these various mattress requirements, manufacturers may market a number of mattress products, each with its own particularized therapeutic function, or may market mattresses that have control units allowing users to program or select different modes of operation. It can be expensive for hospitals or other healthcare institutions to purchase a large number of mattresses, each having its own dedicated therapeutic functionality. However, mattresses allowing user selectable functionality introduce the possibility that users may inadvertently configure the mattress with the wrong type of therapy or operation among the plurality of the available therapies.
• It is sometimes desirable for patients to remain in bed and, in such situations, hospitals are interested in having some type of bed exit alarm for these patients to provide an alarm or alarm signal indicating that the patient has exited, or is about to exit, the bed. Some bed frames have built-in bed exit alarm systems, oftentimes using the load cells of a weigh scale system, to determine the presence or absence of a patient on the bed and triggering a bed exit alarm when a threshold amount of weight is determined to have been removed from the bed. The addition of a weigh scale system to a bed frame adds cost and therefore, hospitals purchase many bed frames without the weigh scale system option and consequently, therefore, without any bed exit alarm capability. Separate bed exit systems having strips or mats that are placed on top of a mattress and underneath a patient are known in the art, but such strips or mats may result in increased interface pressure on the patient and thus, may compromise the ability of the mattress to support the patient with relatively low interface pressure.
SUMMARY OF THE INVENTION
• The present invention comprises an apparatus or system having one or more of the features recited in the appended claims and/or one or more of the following features, which alone or in any combination may comprise patentable subject matter:
• A mattress system may comprise a mattress having at least one inflatable bladder and a control unit. The control unit may comprise a main housing, a source of pneumatic pressure carried by the main housing and operable to inflate the at least one inflatable bladder, and a plurality of user interface modules that are coupleable to the main housing. Each user interface module may be programmed to control inflation of the at least one air bladder differently in at least one operational mode of each of the plurality of user interface modules.
• The user interface modules may include an alternating pressure module and a continuous low pressure module. Additionally or alternatively, the user interface modules may include a rotation therapy module. One or more the user interface modules may be programmed to provide two different types of therapies. Each of user interface modules may have user inputs that are used to change a mode of operation of the associated user interface module. One or more of the user interface modules may be programmed to provide a maximum inflation mode in which the at least one inflatable bladder is inflated to a maximum threshold pressure which renders the at least one air bladder suitably hard for patient transfer. One or more of the user interface modules may include at least one visual indicator that is operable to provide visual indication of the operational status of the mattress system.
• The control unit may have a latch coupled to the main housing and movable between a locked position in which a selected one of the plurality of user interface modules is locked to the main housing and an unlocked position in which the selected one of the plurality of user interface modules is detachable from the main housing. The latch may have a hook and each of the user interface modules may have a post that is captured by the hook when the associated user interface module is locked to the main housing by the latch. The main housing may have at least one slot and each of the plurality of interface modules may have at least one tab that is received in the slot provided in the main housing when the associated user interface module is coupled to the housing.
• Each of the user interface modules may comprise a main body. The post and the at least one tab of each of the plurality of user interface modules may be located on opposite ends of the associated user interface modules. The post and the at least one tab of each of the plurality of user interface modules may extend away from the associated main body in opposite directions.
• The main housing of the control unit may have a recess into which each of the user interface modules is insertable. The control unit may include a first electrical connector coupled to the main housing. Each of the user interface modules may include a second electrical connector that automatically mates with the first electrical connector upon insertion of the user interface module into the recess of the main housing.
• At least one of the plurality of user interface modules may have a lockout switch that is usable to lockout at least one operational mode of the associated user interface module. The lockout switch may be located adjacent a surface, such as a back surface, of the associated user interface module that is inaccessible to a user when the associated user interface module is coupled to the main housing. The lockout switch may be used to lockout the maximum inflation mode of the associated user interface module.
• One or more of the plurality of user interface modules may include inputs that are engageable to enable a bed exit alarm system of the control unit. The bed exit alarm system may receive an input signal from the mattress indicative of a pressure sensed by a pressure sensor situated in an interior region of the surface.
• The source of pneumatic pressure of the control unit may comprise an air compressor within a noise-dampening housing that is situated within an interior region of the main housing. The noise-dampening housing may have an air chamber that serves as a pressure reservoir which stabilizes air flow to the at least one air bladder of the mattress.
• The mattress may at least one valve located within an interior region of the mattress. The valve may be opened and closed to control pressure in the at least one inflatable bladder in a manner dictated by the programming of the selected user interface module that is coupled to the main housing. The mattress may have at least one pressure sensor situated within an interior region of the mattress and an output signal from the at least one pressure sensor may be communicated to the selected user interface module that is coupled to the main housing. At least one cardiopulmonary resuscitation (CPR) input may be coupled to the mattress and may be movable mechanically to deflate the at least one air bladder of the surface. Movement of the CPR input may result in a CPR signal being communicated to the selected user interface module that is coupled to the main housing. The selected user interface module may deactivate operation of the source of pneumatic pressure in response to receiving the CPR signal.
• The control unit may have circuitry that receives a signal from the mattress which is indicative of a pressure sensed by a pressure sensor situated within an interior region of the mattress. The circuitry may use the signal to establish at least one target pressure to which the at least one inflatable bladder is controlled. The circuitry may also use the signal to determine whether to activate a bed exit alarm. The bed exit alarm may comprise a flashing light that is carried by the control unit. Alternatively or additionally, the bed exit alarm may comprise a sound-producing device, such as a speaker or buzzer, carried by the control unit.
• The pressure sensor may comprise a bag filled with silicon oil. The mattress comprises an inflatable underlay having a space that receives the bag filled with silicon oil. The at least one inflatable bladder of the mattress may comprise at least one inflatable layer that overlies the pressure sensor. The at least one inflatable layer may comprise first and second inflatable layers that overlie the pressure sensor. The first inflatable layer may comprise a plurality of laterally extending air bladders, at least two of which are inflatable to different pressures. The second inflatable layer may extend approximately the full length of the mattress and may be inflatable to a single target pressure.
• The mattress may have one or more foam layers, blocks, pads, and/or one or more other non-inflatable support elements in lieu of, or in addition to, the at least one inflatable bladder. Accordingly, the mattress may have no inflatable bladders at all. A pressure sensor comprising an enclosure containing a liquid, such as a bag filled with silicon oil, may be used as part of a bed exit alarm system in such a foam mattress. With regard to mattresses lacking any inflatable bladders, the control unit may be omitted and the circuitry and sound-producing device of the bed exit alarm system may be included within, or coupled directly to, the mattress itself. In other embodiments, some or all of the circuitry and sound producing device of the bed exit alarm system may be situated in a housing or module that is spaced from the mattress and that is coupled to the pressure sensor via one or more electrical lines, or even wirelessly for that matter.
• The mattress may have at least one electrical component situated within an interior region of the mattress, a first pneumatic port in communication with the at least one inflatable bladder of the mattress, and a first electrical connector in communication with the at least one electrical component. The circuitry of the control unit may be programmed to control the manner in which the at least one inflatable bladder is inflated. The circuitry may also include a second electrical connector and the control unit may include a second pneumatic port in communication with the source of pneumatic pressure.
• A connector assembly may be provided to pneumatically connect the first pneumatic port with the second pneumatic port and to electrically connect the first electrical connector with the second electrical connector. The connector assembly may include a pneumatic line, at least one electrical line, and a dual mode plug configured to permit connection of the pneumatic line with the second pneumatic connector substantially simultaneously with connection of the at least one electrical line with the second electrical connector.
• The connector assembly may include a dual lumen hose having side-by-side first and second lumens. The first lumen serves as the pneumatic line for communication of pneumatic pressure from the second pneumatic port of the control unit to the at first pneumatic port of the mattress and the second lumen serves as an electrical conduit through which the at least one electrical line is routed. A first end of the dual lumen hose may be coupled to the dual mode plug. The connector assembly may have a pneumatic coupler mounted to the first lumen at a second end of the dual lumen hose. The least one electrical line may extend beyond the second lumen at the second end of the dual lumen hose.
• The dual mode plug may include a plug housing and at least one latch member coupled to the plug housing. The at least one latch member may be movable between a first position locking the dual mode plug to the main housing of the control unit and a second position unlocking the dual mode plug for detachment from the main housing of the control unit. The at least one latch member may be spring-biased toward the first position. The at least one latch member may comprise a pair of latch members, each situated on an opposite side of the plug housing. The plug housing may include a pair of recesses and at least a portion of each latch member may be received within a respective one of the pair of recesses. The pair of latch members may be movable toward the plug housing to move the pair of latch members between the respective first and second positions.
• The dual mode plug may include a front wall. A pneumatic coupler may extend away from the front wall and an electrical coupler may extend away from the front wall. The pneumatic coupler may be configured to mate with the second pneumatic port of the control unit and the electrical coupler may be configured to mate with the second electrical connector of the control unit. The pneumatic coupler may be formed integrally with the front wall of the dual mode plug and the front wall of the dual mode plug may have an aperture through which the electrical coupler extends. The dual mode plug may include a check valve in communication with the pneumatic coupler.
• Additional features, which alone or in combination with any other feature(s), such as those listed above and those listed in the claims, may comprise patentable subject matter and will become apparent to those skilled in the art upon consideration of the following detailed description of various embodiments exemplifying the best mode of carrying out the embodiments as presently perceived.
BRIEF DESCRIPTION OF THE DRAWINGS
• The detailed description particularly refers to the accompanying figures in which:
• FIG. 1 is an exploded perspective view of a mattress system showing inflatable layers of a mattress of the mattress system situated between top and bottom coverlets of the mattress and showing a control unit situated near a foot end of the bottom of the coverlet coupled electrically and pneumatically by a connector assembly a technical box situated within an interior region of the mattress;
• FIG. 2 is a perspective view of the control unit ofFIG. 1 showing a first user interface module being removed from a recess formed in main housing of the control unit;
• FIG. 3 is a front perspective of the first user interface module ofFIG. 2 showing user inputs on a front surface of the first user interface module;
• FIG. 4 is a front perspective of a second user interface module that is coupleable to the main housing of the control unit in lieu of the first user interface module;
• FIG. 5 is a rear perspective of the second user interface module showing a pair of tabs extending from one end of main body of the module and a post extending from an opposite end of the main body of the module and also showing a lock out switch that is accessible on a rear surface of the main body when the module is detached from the control unit;
• FIG. 6 is rear perspective view of the control unit showing a latch being movable in the direction of the arrow to unlock the user interface module for detachment from the main housing of the control unit;
• FIG. 7ais a side elevation view of the control unit ofFIG. 6, with portions broken away, showing the latch in an unlocked position showing the post situated at an open end of a slot formed in a hook or cam of the latch;
• FIG. 7bis a side elevation view, similar toFIG. 7a, showing the latch in a locked position such that the post of the user interface module is captured within the slot of the hook;
• FIG. 8 is a rear perspective view of the control unit similar toFIG. 6 showing a dual mode plug of the connector assembly coupled to a socket provided in a rear wall of the main housing of the control unit and showing a coupling hook having a cut out beneath the dual mode plug;
• FIG. 9 is a perspective view of the connector assembly showing a dual lumen hose having one end coupled to the dual mode plug and having pneumatic and electrical couplers at an opposite end thereof;
• FIG. 10 is an exploded view of the dual mode plug at the end of the connector assembly that couples to the control unit;
• FIG. 11 is an enlarged perspective view of the end of the connector assembly that couples to the mattress of the mattress system;
• FIG. 12 is an enlarged perspective view showing the pneumatic and electrical couplers of the connector assembly coupled to mating pneumatic and electrical connectors, respectively, included in the mattress;
• FIG. 13 is a diagrammatic view of the mattress system showing a pressure sensor in a middle region of the mattress and having associated sensor circuitry, a technical box at a foot end of the mattress having valves and associated circuitry, and the control unit with its associated circuitry;
• FIG. 14 is a block diagram showing the logic implemented by the circuitry of the mattress system to control a bed exit alarm;
• FIG. 15 is a block diagram showing the logic implemented by the circuitry of the mattress system to control a lock out function provided in each of the user interface modules;
• FIG. 16 is a perspective view of the control unit ofFIG. 1 showing a front shell of the main housing of the control unit pulled away from a back shell of the main housing, a compressor sub-housing situated in the lower region of the back shell, and circuitry of the control unit situated in the back shell above the compressor sub-housing.
DETAILED DESCRIPTION OF THE DRAWINGS
• Amattress system10 includes amattress12 and acontrol unit14 that is spaced-apart from themattress12 and that is coupled pneumatically and electrically with themattress12 by aconnector assembly16 as shown inFIG. 1. As is discussed in greater detail below, thecontrol unit14 includes a plurality ofuser interface modules50,52 that are able to be selectively coupled to amain housing18 of thecontrol unit14 to configure themattress system10 with various functionalities depending upon which of theuser interface modules50,52 is coupled to the main housing. For example,FIG. 3 shows auser interface module50 having a primary mode of operation that is referred to as a continuous low pressure mode andFIG. 4 shows auser interface module52 having a primary mode of operation that is referred to as an alternating pressure therapy mode. Theillustrative mattress system10 is available commercially and is marketed as the ClinActiv™ Therapy Mattress System by Hill-Rom Company, Inc. which is an affiliate corporation of the assignee of the present application.
• Illustratively, themattress12 includes an upperinflatable bladder layer20 having a plurality of laterally-extending cells orbladders22 which cooperate to define various zones oflayer20. For example, a head section zone includes the first threecells22 oflayer20. These threecells22 are fluidly interconnected and are illustratively regulated to the same pressure. The next tencells22 form a torso section zone oflayer20. Finally, a heel section zone includes the last sevencells22 oflayer20 which are fluidly interconnected with each other and are generally regulated to a low target pressure. This target pressure is independent of the rest of the zones of thelayer20 and is regulated by electronics within thecontrol unit14.
• Whensystem10 is operating in the continuous low pressure mode, as dictated bymodule50, the tencells22 of the torso section zone are controlled to the same target pressure. However, whensystem10 is operating in the alternating pressure mode, as dictated bymodule52, a first group of five of the tencells22 of the torso section zone are deflated for a period of time while a second group of five of the tencells22 of the torso section zone are inflated and then, after the period of time and after a dwell time in which all tencells22 of the torso zone section are inflated, the first group of five of the tencells22 of the torso zone section are inflated for a period of time while the second group of fivecells22 of the torso section zone are deflated for a period of time. This sequence then repeats after another dwell time in which all tencells22 of the torso section zone are inflated. Thecells22 of the two groups of torsosection zone cells22 are arranged such that each cell of the first group is situated between adjacent cells of the second group, and vice versa, with the exception of the cells that are the head end and foot end of the torso section zone. In alternative embodiments, other cells oflayer20 also inflate and deflate alternately in addition to the alternating of the inflation and deflation of thecells22 of the torso zone section.
• In the illustrative example, the head, torso, and heel section zones of thelayer20 are controlled and operate independently from one another. Further, while the various head, torso, and heel section zones are described herein as including a particular number of laterally-extending cells, it is within the scope of this disclosure to include any number of independently operable zones having any number of interconnected cells, and having cells of any suitable size, shape, or orientation, including cells that extend longitudinally.
• Themattress12 further includes a firstair mattress underlay24 positioned below thelayer20 as well as a secondair mattress underlay26 positioned below the firstair mattress underlay24. Thus,underlay24 serves as an intermediate layer betweenlayer20 andunderlay26.Underlay24 is a single inflatable bladder but has internal walls or connections, such as radio frequency welds between top and bottom sheets of theunderlay24, running in the longitudinal direction ofmattress12 to prevent ballooning ofunderlay24. Similarly,underlay26 is also a single inflatable bladder but has internal walls or connections running in the lateral direction ofmattress12 to prevent ballooning ofunderlay26. In the illustrative embodiment, the firstair mattress underlay24 and the secondair mattress underlay26 are interconnected via conduits with each other and with the head section zone oflayer20 and are inflated to the same pressure as the head section zone of thelayer20. Themattress12 further includes atop coverlet28 and abottom coverlet30 which are coupled together by suitable couplers, such as one or more zippers, to maintain thelayer20 and underlays24,26 within an interior region of themattress12.
• Layer20 and underlays24,26 are inflatable patient support elements ofillustrative mattress12. It should be appreciated that the constructional details ofelements20,24,26 are merely illustrative andmattress12 may have inflatable elements of other shapes, sizes, or orientations. Furthermore,mattress12 may have non-inflatable patient support elements, such as foam layers, blocks, pads, and the like, as well as mesh materials, gel layers, quilting, and the like, in lieu of or in addition toelements20,24,26. Accordingly, mattresses having no inflatable elements at all are within the scope of this disclosure.
• Theillustrative mattress12 further includes apressure sensor32 and atechnical box34 containing anair distribution system35 which includes a set ofvalves37, associatedcircuitry39, and amanifold assembly33 in fluid communication with thevarious cells22 oflayer20 as well as with the first and second air mattress underlays24,26 as shown diagrammatically inFIG. 13. Themanifold assembly33 includes a pneumatic input and a plurality of pneumatic outputs, each of which is associated its own valve of the set ofvalves37. In one embodiment, a first valve is in fluid communication with the group of fivebladders22 of the torso section zone while a second valve is in fluid communication with the second group of fivebladders22 of the torso section zone. The first and second sets ofbladders22 in the torso section zone are arranged alternately and the first andsecond valves37 are controlled to inflate and deflate the first and second groups ofbladders22 of the torso section zone alternately whenmattress system10 is operating in the alternating pressure mode as dictated by the programming ofuser interface module52 as mentioned above. If, on the other hand,user interface module50 is coupled to themain housing18 ofcontrol unit14, then the first andsecond valves37 are controlled so that all ten of thebladders22 of the torso zone section remain inflated simultaneously to the same target pressure.
• The set ofvalves37 includes a third valve in fluid communication with the heel zone of thelayer20 and a fourth valve that is in communication with the head section zone of thelayer20, thefirst mattress underlay24, and thesecond mattress underlay26. Thevalves37 operate to open and close various passageways of themanifold assembly33 as is appropriate to allow inflation or deflation of the associated groups of bladders ofmattress12. In some embodiments, each of thevalves37 is a three-way valve having an opened position allowing pressurized air to be pumped to the associatedbladders22; a closed position blocking air from being pumped to, and blocking air from escaping from, the associatedbladders22 and underlays24,26; and a vent position allowing air to vent frombladders22 and underlays24,26 to atmosphere. In other embodiments, one more of thevalves37 are two position valves and a separate vent valve is provided to vent air from each of the various groups of bladders as needed. In some embodiments, thevalves37 are solenoid valves. However, other suitable valves, such as proportional control valves, may be used if desired. Thetechnical box34further houses circuitry39, referred to herein sometimes as the manifold printed circuit board (PCB) for controlling the operation of thevalves37 within thetechnical box34. As is discussed in greater detail below, the manifold PCB is in electrical communication with thecontrol unit14.
• Illustratively, thepressure sensor32 is positioned within a cut-outsection36 formed in the secondair mattress underlay26 as shown inFIG. 1 while thetechnical box34 is positioned at a foot end of themattress12 such that foot ends of the air mattress underlays24,26 generally abut the technical box but do not extend over the top of thetechnical box34. However, the layer20 (and particularly theheel zone bladders22 of the layer20) extends over thetechnical box34. When themattress12 is assembled, thepressure sensor32 of themattress12 is positioned generally below the torso section zone of thelayer20 in order to sense the pressure exerted by a patient on the torso section zone and provide an output signal to thecontrol unit14 indicating the sensed pressure.
• Mattress12 includes a cardiopulmonary resuscitation (CPR) assembly that is coupled to thetechnical box34 and that includes arotatable knob40 that is accessible to the caregiver through anaperture42 formed in the foot end portion of thebottom coverlet30. In normal operation, theCPR knob40 is in a closed position. When theCPR knob40 is moved manually by a caregiver to an opened position, air rapidly vents through the CPR assembly to atmosphere. In addition, an electrical signal is provided by a switch or other sensor tocircuitry39, the circuitry ofcontrol unit14, and the circuitry ofsensor32 to indicate that theCPR knob40 has been moved to the opened position. In response to this signal,control unit14 deactivates operation of the source of apneumatic pressure43, such as a compressor, of thecontrol unit14. A CPR indicator light flashes on thecontrol unit14 and a CPR alarm sound beeps regularly every 30 seconds to alert the caregiver that theCPR knob40 has been activated. Once activated, the bladders oflayer20 and underlays24,26 quickly deflate to provide a firm surface for performing CPR on the patient lying atop themattress12.
• Illustratively, thepressure sensor32 of themattress12 comprises a liquid-containingflexible enclosure45 and associatedcircuitry47 as shown inFIGS. 1 and 13.Enclosure45 andcircuitry47 are both situated in the cut-outsection36 ofunderlay26. In some embodiments, the liquid-containingenclosure45 comprises a bag or bladder filled with a silicon oil, such as polydimethylsiloxane.Circuitry47 includes a pressure transducer which is exposed to the fluid pressure in the bag via a conduit. The transducer ofcircuitry47 detects the pressure exerted upon it by the liquid and relays a pressure signal to thecontrol unit14 viacircuitry47 andcircuitry39. The pressure sensed by the transducer correlates to the amount of weight and pressure exerted onenclosure45, which correlates to the weight of the patient on the mattress. As is discussed in greater detail below, circuitry within thecontrol unit14 operates to establish the target pressures of the zones oflayer20 and underlays24,26 and also determines whether one or more zones of thelayer20 are to be inflated or deflated based upon information received from the pressure signal. The principles of operation of thepressure sensor32 is described in greater detail in U.S. Pat. No. 6,094,762 which is owned by the same assignee as the present application and which is hereby incorporated by reference herein.
• As mentioned above, thepressure sensor32 is positioned below the torso section zone oflayer20. Accordingly, as the patient's torso applies pressure on themattress12, this pressure is transferred as a force to theenclosure45 ofpressure sensor32. The pressure in theenclosure45 is detected by the transducer ofcircuitry47 and a pressure signal is sent to thecontrol unit14. Circuitry within thecontrol unit14 then determines whether to vent air from thelayer20 and/or underlays24,26 of themattress12 or to turn on thepneumatic source43 within thecontrol unit14 to inflate thelayer20 and/or underlays24,26 in order to reach respective target pressures which are established bycontrol unit14 based on the signal received fromsensor32. Accordingly, the target pressures ofcells22 oflayer20 and underlays24,26 of themattress12 are adjusted automatically to accommodate each individual patient's weight and position. In some embodiments, a pressure comparator is provided incircuitry47 to make a comparison between the pressure inenclosure45 and the pressure in the headsection zone bladders22 oflayer20 and theunderlays24,26 and then controlunit14 andvalves37 are operated to equalize the pressure therebetween. In such an arrangement, any additional pressure sensor to sense the pressure in headsection zone bladders22 oflayer22 and underlays24,26 may be omitted.
• In some embodiments,additional pressure sensors41 are provided intechnical box34 and are associated with respective pneumatic lines used to inflatelayer20 and underlays24,26. The additional pressure sensors detect and communicate the pressure within each zone of thelayer20 and within theunderlays24,26 to thecontrol unit14. Such measured pressures are compared with the target pressure values established by the circuitry ofcontrol unit14 based on the pressure signal originating frompressure sensor32. In other embodiments,technical box34 has only asingle pressure sensor41 which is coupled sequentially, by appropriate opening and closing of thevarious valves37, to each of the zones oflayer22 and to underlays24,26 to measure sequentially the pressures in each of the zones.
• The data frompressure sensor32 is used in three distinct operation modes ofsystem10 including stand-by regulation, patient egress surveillance, and main zone pressure regulation. As is discussed in greater detail below, the stand-by regulation mode means thatsystem10 operates to achieve a relatively low pressure in themattress12 so as to provide a ready-to-use, and yet comfortable, support when the patient is initially placed on themattress12. The patient egress surveillance mode means thatsystem10 operates to monitor the presence and absence of the patient on themattress12. The main zone pressure regulation mode means thatsystem10 operates to control the internal pressures in thebladders22 oflayer20 and underlays24,26. Illustratively, thecircuitry47 ofpressure sensor32 is in electrical communication with thecircuitry39 situated within thetechnical box34. As noted above, thecircuitry39 within thetechnical box34 is in electrical communication with thecontrol unit14 via theconnector assembly16.
• Referring now toFIGS. 2-6, thecontrol unit14 includes themain housing18, a source ofpneumatic pressure43 such as a pump, blower, or compressor (shown diagrammatically inFIG. 13) contained within themain housing18, and first and seconduser interface modules50,52 that are selectively coupleable to themain housing18. Thecompressor43 of thecontrol unit14 is enclosed in a sub-housing49, shown inFIG. 16, within themain housing18 of thecontrol unit14 to dampen noise while thecompressor43 is running. Power is provided tounit14 via apower cord19, shown inFIG. 1, which plugs intounit14 and into a standard electrical outlet to receive power therefrom. Illustratively, the sub-housing49 is made of aluminum; however, is should be understood that the sub-housing49 may be made of other suitable materials to dampen the noise of thecompressor43 contained therein. Further, anair chamber51 of thecontrol unit14 is positioned generally in top region of thecompressor sub-housing49 in order to serve as a pressure reservoir that stabilizes the air flow within thecontrol unit14 as well as reduce noise output of thecontrol unit14.
• Each of the first and seconduser interface modules50,52 are programmed to control inflation of thelayer20 and/or underlays24,26 of themattress12 differently in various operational modes of each ofinterface module50,52. Illustratively, the front side of themain housing18 includes a recess54 provided therein. Theinterface modules50,52 are each selectively received within the recess54 and are locked in place by alatch90 of thecontrol unit14, as is discussed in greater detail below with regard toFIGS. 7aand7b. Theuser interface modules50,52 operate as the main caregiver controls of themattress system10 while also providing feedback to the caregiver as to the operational status of thesystem10. Each of themodules50,52 includes circuitry that is programmed with instructions that dictate the operational modes ofsystem10.
• Referring toFIG. 3, the firstuser interface module50 includes auser interface panel55 having afront surface56 and amain body57 that is coupled to theuser interface panel55 and that has arear surface58. Illustratively, the firstuser interface module50 is a continuous low pressure (CLP) therapy module. The CLP mode of themodule50 is automatically activated when theCLP module50 is placed in the recess54 of thecontrol unit14 and themain switch53 of control unit14 (seeFIG. 16) is switched on. Illustratively, theCLP module50 andmodule52 each include anelectrical connector59 on therear surface58 of themain housing57 as shown inFIG. 5 with regard tomodule52. Theelectrical connector59 is coupled to anelectrical coupler61, shown inFIG. 2, within the recess54 of thecontrol unit14 to provide electrical communication between themodule50 andinternal circuitry63, shown inFIG. 16, of thecontrol unit14. Aribbon cable65, also shown inFIG. 16,interconnects connector61 andcircuitry63.
• During the CLP mode, the tencells22 in the torso section of thelayer20 are regulated to the same target pressure (all targets pressures referred to herein have associated tolerance ranges as is well known in the art) as set by thepressure sensor32. As mentioned above, the threehead section cells22 of thelayer20, thefirst underlay mattress24, and thesecond underlay mattress26 are fluidly interconnected with each other and are inflated to the same pressure as thecells22 of the torso section of thelayer20 during the CLP mode. The sevenfoot section cells22 of thelayer20 are regulated to a lower target pressure which is determined independently of the rest of the mattress sections.
• Various user inputs and indicators are provided on thefront surface56 of theuser input panel55 of themodule50 as shown inFIG. 3. For example, an on/offbutton58 is engaged by a user to turn themodule50 on or off. Alight indicator60 illuminates to denote that themodule50 has been turned on. Upon first connecting thecontrol unit14 to the main power supply, themattress system10 operates to automatically inflate thelayer20 and underlays24,26 to a maximum inflation pressure value to fully expand thecells22 and underlays24,26. Themattress system10 then automatically reverts to the therapy mode provided by the selectedmodule50 or52 after approximately eight minutes. During start up, the caregiver may press the on/offbutton58 twice to override the maximum inflation function, if desired.
• An internal pressure indicator provides an indication of the pressure variation in the torso zone of thelayer20. Segments of thelight indicator62 will illuminate as the pressure within the torso zone automatically varies. A maximum inflation (P-max)button64 is engaged by user to inflatelayer20 and underlays24,26 to the maximum inflation pressure at the user's discretion. Thus, themaximum inflation button64 may then be activated at any time in order to inflate thelayer20 and underlays24,26 to the maximum inflation pressure. Oftentimes, for example, a caregiver may use the maximum inflatebutton64 in order to provide a firmer patient support surface for patient transfers or bedding changes. Illustratively, pressing the maximum inflation button64 a second time will immediately end the maximum inflation mode and return themattress12 to the therapy mode. The maximum inflation pressure is a target pressure that is typically higher than the pressures to whichlayer20 and/or underlays24,26 are inflated during other modes of operation ofsystem10 and it should be understood thatlayer20 and underlays24,26 are capable of withstanding even higher pressures than the one referred to as the maximum inflation pressure in this disclosure.
• Pressing a bed exit alarm button66 of theuser interface module50 arms or enables a patient egress surveillance system (sometimes referred to herein as a “bed exit system” or “bed exit alarm system” or the like). As is discussed in greater detail below, thepressure sensor32 of themattress12 operates to detect the presence and absence of a patient on themattress12 by sending a pressure signal to thecontrol unit14. Circuitry of thecontrol unit14 then determines, based upon the value of the pressure signal, whether the patient is present on, or absent from, themattress12. The determination regarding the presence of absence of the patient is made by comparing the pressure sensed bysensor32 with a threshold value. If it is determined that the patient is absent from themattress12, an alarm to alert a caregiver is activated if the bed exit alarm system is enabled. The alarm may be a visual alarm such as a light indicator on themodule50 and/or may be an audible alarm such as a beeping noise made by a sound-producing device such as a speaker or piezoelectric buzzer, for example. When the bed exit alarm function is enabled, alight indicator68 on themodule50 is illuminated.
• Analarm silence button70 of themodule50 may be engaged by a user to temporarily silence any audible alarm associated with the maximum inflation function, the CPR function, a power failure, and/or a mattress malfunction. For example, when one or more of the above-referenced alarms are sounding, the caregiver may press thealarm silence button70 to temporarily silence the sounding alarm(s). The alarm(s) will then sound again after approximately 10 minutes if the condition causing the alarm is not rectified. The alarm(s) may also be permanently silenced by pressing thealarm silence button70 until the light indicator72 flashes. In some embodiments, thealarm silence button70 also may be engaged by the user to silence a bed exit alarm.
• ACPR light indicator74 of themodule50 flashes when the CPR function, discussed above, is activated. A seat cushionlight indicator76 illuminates when an optional seat cushion (not shown) of themattress system10 is being inflated. Theindicator76 turns off after approximately five minutes once the seat cushion is completely inflated. Illustratively, during inflation of the seat cushion, the maximum inflation function is automatically activated without audible indication. The seat cushion inflation may be stopped at any time by pressing themaximum inflation button64. Once inflated, the seat cushion is disconnected fromcontrol unit14 and remains inflated for use on a wheel chair or other type of seating surface. A valve coupled to the seat cushion may be open to allow deflation of the seat cushion to atmosphere.
• A safety lock-outlight indicator78 of themodule50 illuminates whenever theuser interface module50 is locked-out to prevent a patient or caregiver from adjusting the settings. Illustratively, as shown inFIG. 5 with regard tomodule52, the rear surface of themodule50 and themodule52 each includes a lock-out switch80. The caregiver may move the lock-out switch80 to an activated position in order to lock-out the controls of themodule50 or themodule52, as the case may be, to prevent a patient or other caregiver from tampering with the particular settings of themodule50,52, thereby to prevent intentional or unintentional changes in the operating mode ofsystem10. Illustratively, the lock-out switch80 is located on therear surface58 of themodule50,52 and is, therefore, generally inaccessible by the patient. The safety lock-outindicator78 is illuminated when the lock-out switch80 has been activated. Illustratively, the safety lock-out indicator light78 will then flash in the event of a control button being pressed in order to signal that the user interface is locked-out.
• To unlock the lock-out function, the caregiver removes themodule50 from thehousing18 of thecontrol unit14 and moves the lock-out switch80 to the deactivated or unlocked position. Alternatively, the caregiver may temporarily unlock the lock-out function by removing themodule50 from thehousing18 and pressing a lock-out button81 adjacent theswitch80. Illustratively, pressing the lock-out button81 (while maintaining theswitch80 in the activated position) operates to deactivate the lock-out function for a predetermined period of time, such as 20 seconds, for example. This function allows the user then to resecure themodule50 to thehousing18 and manipulate the controls of themodule50 without having to again remove themodule50 from the housing to reinitiate the safety lock-out function. Once the caregiver has manipulated the controls of themodule50, the lock-out function will be automatically reactivated once the predetermined period of time has elapsed.
• A power failurelight indicator82 illuminates when thecontrol unit14 is disconnected from the main power supply or in the event of a power failure. The power failurelight indicator82 will also illuminate during transport. A mattress malfunction light indicator84 ofmodule50 illuminates in the event of a pressure fault and a continuous low pressure (CLP) therapy indicator86 ofmodule50 illuminates to indicate that CLP therapy is being used.
• Illustratively, as noted above, an audible alarm is sounded, as well as a visual indicator being illuminated, when the maximum inflation function has been activated, when the CPR function has been activated, when a patient has exited the bed (assuming the bed exit alarm system is enabled), when thecontrol unit14 has been disconnected from the main power supply or when a power failure has occurred, and when a mattress defect is detected.
• Referring now toFIG. 4, the seconduser interface module52 similarly includes theuser interface panel55 having thefront surface56 and themain body57 having therear surface58. Illustratively the seconduser interface module52 is an alternating pressure (AP) therapy module. The AP therapy mode is automatically activated when theAP module52 is placed within the recess54 of themain housing18 of thecontrol unit14. Illustratively, the AP mode affects the tencells22 within the torso section zone of thelayer20 to sequentially inflate and deflate everyother cell22 within the torso section zone. Accordingly, none of the threehead section cells22 and none of the sevenheel section cells22 are alternately inflated and deflated in the illustrative embodiment, but may do so in other embodiments.
• As noted above, the pressure in thetorso section cells22 is controlled by thepressure sensor32. Illustratively, the AP mode may be described in three phases. In the first phase, five non-adjacent cells22 (forming a first AP zone of cells) in the torso section zone of thelayer20 are deflated. This deflation takes approximately four minutes. In the second phase, the pressure in all thecells22 within the torso section is the same (i.e., at a continuous low pressure). The duration of the second phase is approximately 1 minute. The purpose of the second phase of the AP therapy mode is to enhance patient comfort by providing a soft surface between the deflated phases. In the third phase, the other five non-adjacent cells22 (forming a second AP zone of cells) in the torso section zone of thelayer20 are deflated. Similar to the first phase, the third phase lasts approximately four minutes. A similar discussion of the AP mode is presented above.
• Various user inputs and indicators are provided on thefront surface56 of theuser input panel55 of themodule52. Illustratively, many of these user inputs are the same as those discussed above with respect to the firstuser interface module50. As such, like reference numerals have been used to denote like inputs and/or indicators. However, rather than including the CLP indicator86 of themodule50, themodule52 includes an alternating pressure (AP) therapy indicator88 to indicate that AP therapy is being used.
• Although the CLPuser interface module50 and the APuser interface module52 are provided in the illustrative examples, it is within the scope of this disclosure for themattress system10 to include other user interface modules that are selectively coupleable with thecontrol unit14 as well. For example, a rotation therapy user interface module may provide a continuous lateral rotation therapy (CLRT) function and a low air loss user interface module may provide a low air loss function for cooling the patient and/or wicking moisture away from the patient. Of course, it should be understood that any number of user interface modules having any number of therapy functions may be provided for use with thecontrol unit14 andmattress12 of themattress system10. Further, it is within the scope of this disclosure to include more than one therapy function on a single user interface module. For example, while each of the CLP andAP modules50,52 are dedicated to a single therapy, a single user interface module may be provided which includes both CLP and AP therapies. Accordingly, any number and any combination of desired therapies may be provided on a single user interface module. Each user interface module includes circuitry that is programmed to implement its associated functionalities. Thus, the programming of the various types of modules is different. This provides a cost savings to healthcare facilities because, to achieve different types of patient therapies, only the associated user interface modules need to be purchased rather than having to purchase an entirely different mattress system.
• Each of theuser interface modules50,52 further includes a lockingpost92 extending from a first end of94 themain body57 of therespective module50,52, as shown inFIGS. 3 and 4. Referring now toFIG. 5, a pair oftabs96 of eachuser interface module50,52 extend outwardly from asecond end98 of themain body57 of therespective module50,52. Thus, post92 andtabs96 extend frommain body57 in opposite directions. As is discussed below, the lockingpost92 andtabs96 are used to secure therespective modules50,52 within the recess54 formed in themain housing18 of thecontrol unit14.
• As noted above, theuser interface modules50,52 may be selectively attached to and removed from themain housing18 of thecontrol unit14. In order to attach one of the first and seconduser interface modules50,52 to themain housing18 of thecontrol unit14, the caregiver slides the pair oftabs96 of the selectedmodule50 or52 into correspondingslots67, shown inFIG. 2 (in phantom), formed in themain housing18 of thecontrol unit14. In the illustrative embodiment, the slots of thehousing18 are formed in a side wall ofhousing18 defining part of the recess54. Once thetabs96 of the selectedmodule50 or52 are received within the corresponding slots of thehousing18, themain body57 of the selectedmodule50 or52 may further moved into the recess54 such that the lockingpost92 is received within aslot97 defined byhook portion98 of apivotable cam99 coupled to thelatch90 to further secure the selectedmodule50 or52 within thehousing18. Illustratively, as shown inFIGS. 7aand7b, movement of thelatch90 in afirst direction101 operates to rotate thecam99 in a clockwise direction such that theslot97 of thehook portion98 captures thepost92 of the selectedmodule50 or52 therein (as shown inFIG. 7b).
• In order to remove one of the first and seconduser interface modules50,52 from thecontrol unit14, the caregiver may rotate thelatch90 located at the rear side of thecontrol unit housing18 indirection103 shown inFIG. 7bfrom a first, locked position to a second, unlocked position. Illustratively, movement of thelatch90 indirection103 operates to rotate thecam99 in a counterclockwise direction such that thepost92 of the selectedmodule50 or52 becomes disengaged from theslot97 of the hook portion98 (as shown inFIG. 7a). When thelatch90 is in the second, unlocked position, hook98 of thecam99 is disengaged from thepost92 of the selectedmodule50 or52 to allow the caregiver to remove the particularuser interface module50 or52 from themain housing18 of thecontrol unit14.
• The shape ofslot97 is such that whenlatch90 is rotated indirection101, withhook portion98 capturingpost92, post92 is pulled generally radially inwardly toward the pivot axis oflatch90 to firmly seat the associatedmodule50,52 against themain housing18 and to pull theelectrical connectors59,61 together. On the other hand, whenlatch90 is rotated indirection103, withhook portion98 capturingpost92, post92 is pushed generally radially outwardly way from the pivot axis oflatch90 to unseat the associatedmodule50,52 from housing and to push theelectrical connectors59,61 apart. After being unseated in this manner, themodule50,52 is far enough away frommain housing18 to provide space for a user to grasp themodule50,52, as shown inFIG. 7awith regard tomodule50, and completely detach it fromhousing18.
• Referring now toFIG. 8, thecontrol unit14 further includes asocket100 formed in arear wall102 of themain housing18 as well as a bracket assembly orcoupling hook104 coupled to therear side102 of themain housing18. As is discussed in greater detail below, thesocket100 ofcontrol unit14 receives adual mode plug110 of theconnector assembly16 therein. Illustratively, thecoupling hook104 is positioned below thesocket100 of themain housing18 and is provided to allow a caregiver to hang thecontrol unit14 on a footboard or side rail of a bed frame, for example.Hook104 has acutout101 to accommodate thedual mode plug110 and a user's fingers when attaching theconnector assembly16 to, or detaching theconnector assembly16 from,housing18. Thecontrol unit14 also includes rubber pads (not shown) on a bottom surface of themain housing18 in order to enable thecontrol unit14 to stand on a hard surface as well.
• Referring now toFIGS. 9-12, theconnector assembly16 of themattress system10 provides a pneumatic and electrical connection between thecontrol unit14 and themattress12. Theconnector assembly16 includes adual lumen hose118 including apneumatic line120 for communication of pneumatic pressure from thecontrol unit14 to themattress12 and anelectrical line122 that serves as an electrical conduit through which electrical conductors are routed between thecontrol unit14 and themattress12. Illustratively, thepneumatic line120 and theelectrical line122 are connected to each other and positioned side-by-side along a majority of the length of thelines120,122, as shown inFIG. 9, for example.
• Theconnector assembly16 further includes thedual mode plug110 at a first end of thedual lumen hose118. Thedual mode plug110 is received within thesocket100 of themain housing18 in order to provide a substantially simultaneous pneumatic and electrical connection with thecontrol unit14. Illustratively, thedual mode plug110 includes aplug housing124 and twolatch members126 coupled to respective sides of theplug housing124. In particular, theplug housing124 includes a pair ofrecesses127 formed in each side of theplug housing124 such that a portion of eachlatch member126 is received within arespective recess127. Each of thelatch members126 are movable between a first position locking thedual mode plug110 to themain housing18 of thecontrol unit14 and a second position unlocking thedual mode plug110 from themain housing18 of thecontrol unit14. Illustratively, thelatch members126 are spring-biased toward the first position byrespective springs128, shown inFIG. 10. Further, in order to move thelatch members126 between the first and second positions, a caregiver squeezes eachlatch member126 in a direction generally toward theplug housing124 and further within therespective recesses127.
• Referring still toFIG. 10, thedual mode plug110 further includes afront wall130 coupled to thehousing124, apneumatic coupler132 extending away from thefront wall130, and anelectric coupler134 that extends beyondfront wall130 through anaperture133 formed therein. A first end of each of the electrical conductors routed throughline122 is coupled to, and terminates at,electrical connector134. Thecontrol unit14 includes an electrical connector107 (shown diagrammatically inFIG. 13) within thesocket100 which is in communication with theinternal circuitry63control housing14 and a pneumatic port109 (also shown diagrammatically inFIG. 13) within thesocket100 which is in communication with thecompressor43 of thecontrol unit14. Accordingly, when thedual mode plug110 is received within thesocket100 of thecontrol unit14, thepneumatic coupler132 of theplug110 is coupled to thepneumatic port109 of thecontrol unit14 and theelectric coupler134 of theplug110 is coupled to theelectrical connector107 of thecontrol unit14. Further, thedual mode plug110 is configured so that the electrical and pneumatic connections between theconnector assembly16 and thecontrol unit14 are made substantially simultaneously.
• Acheck valve131 is provided withinhousing124 ofplug110 and is in pneumatic communication withport132. Whenplug110 is coupled tosocket100 andcompressor43 is operated, thecheck valve131 is opened to allow pressurized air to move throughpneumatic line120. Whenplug110 is disconnected fromsocket100,check valve131 is closed to prevent air from escaping frommattress14 throughconnector assembly16.
• Latch members126 each have a rearwardly projectingtab111 that is captured within arear pocket121 of therespective recess127 and a forwardly projectingtab113 that extends through arespective aperture115 offront wall130.Apertures115 are oversized in the lateral direction to allow movement oftabs113 therein whenlatch members126 move between the first and second positions. Eachlatch member126 also has a laterally inwardly projectingtab117 that is received in an associatedslot119 formed in a respective side ofhousing124. Receipt oftabs111,113 in the associatedpockets121 andapertures115 retainslatch members126 in place withinrecess127, whereas receipt oftabs117 inslots119 guides the lateral movement oflatch members126. Each oflatch members126 further has a laterally outwardly projectingtabs123 that is received in associated tab-receiving recess orpocket125, shown inFIG. 8 (in phantom), formed in the sidewalls ofsocket100. Receipt oftabs123 inrecesses125 locks plug110 to thesocket100 of thehousing18 of thecontrol unit14. Whenlatch members126 are squeezed towardhousing124 ofplug110,tabs123 are withdrawn fromrecesses125, thereby allowingplug110 to be disconnected fromsocket100.
• Referring now toFIGS. 9 and 11, theconnector assembly16 further includes apneumatic coupler140 mounted to the second end of thepneumatic line120 and anelectrical connector142 mounted to an end of acable141 of the electrical conductors which exit from the second end of theelectrical line122. As shown inFIG. 12, thepneumatic coupler140 is coupled to apneumatic port144 of themattress12. Specifically, thetechnical box34 includes thepneumatic port140 which is in pneumatic communication with theinflatable layer20 and underlays24,26 of themattress12 via themanifold assembly35 within thetechnical box34. Further, theelectrical connector142 of theconnector assembly16 is coupled to anelectrical connector146 of thetechnical box34 of themattress12. Theelectrical connector146 of themattress12 is in electrical communication with theelectrical circuitry39,47 within themattress12. Further illustratively, thetechnical box34 includes a firstpressure test port150 for checking the pressure in the torso zone of thelayer20 and a secondpressure test port152 for checking the pressure in the heel zone of thelayer20.Pressure transducers41 oftechnical box34 are coupled electrically to testports150,152 to provide feedback information regarding the pressure within an associated zone ofmattress14.
• In operation, air enters thecontrol unit14 through an air filter (not shown) within thecontrol housing18 of thecontrol unit14. The air then travels into the compressor inlet. Upon exiting thecompressor43, the air travels throughcheck valve131 and thepneumatic line120 of theconnector assembly16 and into themanifold assembly35 located in thetechnical box34 within an interior region of themattress12. The air is then dispatched throughvalves37 into the various inflatable mattress layers including thelayer20, the firstair mattress underlay24, and thesecond mattress underlay26. In the illustrative embodiment, thecheck valve131 located insideplug110 of theconnector assembly16 provides approximately four hours of inflation of themattress12 in the event thecontrol unit14 is disconnected from the main power supply or if thedual lumen hose118 is disconnected from thecontrol unit14.
• As mentioned above, each ofmodules50,52 is programmed to providesystem10 with a bed exit alarm function.FIG. 14 is a diagram which illustrates the logic of the bed exit alarm function ofsystem10.Sensor32 provides a signal tocircuitry47 which measures the pressure exerted onsensor32 as indicated atblock160. Acomparator162 receives the pressure measurement signal and also receives a threshold setting signal which is represented byblock164 inFIG. 14. In one embodiment, the threshold setting is established for a minimum patient weight of fifty pounds but, in other embodiments, other threshold settings may be established at the discretion of the system programmer or designer.
• If the pressure measurement signal is less than the threshold value signal, which is an indication that the patient has exited themattress14, then the output ofcomparator162 is on (e.g., a high logic state), otherwise the output ofcomparator162 is off (e.g., a low logic state). If the comparator is turned on, thensystem10 automatically operates in the stand by mattress pressure regulation mode in whichlayer20 and underlays24,26 are controlled to reduced pressure settings as indicated atblock166. If the bed exit or patient egress alarm is enabled, as indicated atblock168 and the comparator is on, then the output of an ANDgate170 is on. The output of ANDgate170 is input to another ANDgate172 which has a second input from a 1 Hertz (Hz)clock174. Thus, if the output of ANDgate170 is on, then the output of ANDgate172 will be a 1 Hz signal that is fed to patient egress alarm indicator as indicated atblock176.
• As mentioned above the bed exit alarm may include a visual indicator, such as a light emitting diode (LED) and/or a sound producing device, such as a speaker or buzzer. In the illustrative embodiment, the 1 Hz signal being output from ANDgate172 will cause the visual indicator to flash at a rate of 1 Hz and will cause the sound producing device to beep at a rate of 1 Hz. Although, logical ANDgates170,172 are used inFIG. 14 to explain the operation of the bed exit alarm function ofsystem10, it should be appreciated that the logical AND conditions may be implemented by software rather than by use of discrete logic gates, but use of discrete logic gates is within the scope of the disclosure as well.
• As mentioned above, each ofmodules50,52 includes lock-out switch80 and lock-out button81 which are used to lock out various functions of themodules50,52 and to unlock the functions.FIG. 15 is a diagram which illustrates the logic of the lock out function ofsystem10. Whenswitch80 is in its position enabling various functions ofsystem10, an output of anOR gate178 is turned on (i.e., a high logic state) and is coupled to the input of a set of ANDgates180, each of which is associated with a respective function as indicated generically at a “function A”block182 and at a “function Z”block184 inFIG. 15. A “function key A”switch186 is coupled to the input of the ANDgate180 associated with function A and a “function key Z”switch188 is coupled to the input of the ANDgate180 associated with function Z. Function A and function Z are intended to generically represent the functions ofsystem10. The dotted lines appearing inFIG. 15 betweenswitches186,188 and between the output of ORgate178 and the AND gate associated with function Z are intended to convey the notion that additional functions may be controlled in the same manner as the two that are illustrated.
• When the output of ORgate178 is on, which occurs whensystem10 is enabled, andbutton186 orbutton188 is pressed, the associated AND gate has two high logic states at its input resulting in its associated output being turned on (i.e., a high logic state) to signal the operation of the associated function A or function Z. Ifswitch80 is in its position disabling or locking out the various functions ofsystem10, and assumingbutton81 is not pressed, then both inputs to ORgate178 are at low logic states and the output of ORgate178 is off (i.e., a low logic state) resulting in the output of the associated ANDgates180 being turned off, regardless of whether either ofbuttons186,188 is pressed.
• Ifswitch80 is in its position locking out the various functions ofsystem10 andswitch81 is pressed, then a twenty second timer is activated, as indicated atblock190, resulting in a high logic state being applied at one of the inputs of ORgate178 for twenty seconds, thereby turning the output of ORgate178 on, thereby enabling the various functions ofsystem10 for twenty seconds. During this twenty period, switches186,188 may be pressed to operate the associatedfunction182,184. After the expiration of the twenty second timer, theOR gate178 once again receives two low logic inputs which turns off the output of theOR gate178 thereby locking out the functions ofsystem10.
• Switches186,188 are coupled to the inputs of anOR gate192 as shown inFIG. 15. The output of ORgate192 is coupled to alock light194.Lock light194 is turned on byOR gate192 whenswitch80 is in its position locking out the functions ofsystem10 and lock light194 flashes if either ofswitches186,188 is pressed whensystem10 is locked out. Although, logical ANDgates180 and logical ORgates178,192 are used inFIG. 15 to explain the operation of the lock out function ofsystem10, it should be appreciated that the logical AND and logical OR conditions may be implemented by software rather than by use of discrete logic gates, but use of discrete logic gates is within the scope of the disclosure as well.
• Although certain illustrative embodiments have been described in detail above, variations and modifications exist within the scope and spirit of this disclosure as described and as defined in the following claims.

Claims (32)

1. A mattress system comprising

a mattress including at least one inflatable bladder and a pressure sensor situated within an interior region of the mattress, and

a control unit spaced from the mattress and having circuitry that receives a signal from the mattress which is indicative of a pressure sensed by the pressure sensor, the circuitry using the signal to establish at least one target pressure to which the at least one inflatable bladder is controlled and the circuitry also using the signal to determine whether to activate a bed exit alarm.

2. The mattress system ofclaim 1, wherein the pressure sensor comprises a bag filled with silicon oil.

3. The mattress system ofclaim 2, wherein the mattress comprises an inflatable underlay having a space that receives the bag filled with silicon oil.

4. The mattress system ofclaim 1, wherein the at least one inflatable bladder comprises at least one inflatable layer that overlies the pressure sensor.

5. The mattress system ofclaim 4, wherein the at least one inflatable layer comprises first and second inflatable layers that overlie the pressure sensor.

6. The mattress system ofclaim 5, wherein the first inflatable layer comprises a plurality of laterally extending air bladders, at least two of which are inflatable to different pressures, and the second inflatable layer extends approximately the full length of the mattress and is inflatable to a single target pressure.

7. The mattress system ofclaim 1, wherein the bed exit alarm comprises a flashing light that is carried by the control unit.

8. The mattress system ofclaim 1, wherein the bed exit alarm comprises a sound-producing device carried by the control unit.

9. A mattress system comprising

a mattress having at least one inflatable bladder, at least one electrical component situated within an interior region of the mattress, a first pneumatic port in communication with the at least one inflatable bladder, and a first electrical connector in communication with the at least one electrical component,

a control unit spaced from the mattress and comprising a main housing, a source of pneumatic pressure carried by the main housing and operable to inflate the at least one inflatable bladder, and circuitry programmed to control the manner in which the at least one inflatable bladder is inflated, the circuitry including a second electrical connector, the control unit including a second pneumatic port in communication with the source of pneumatic pressure, and

a connector assembly to pneumatically connect the first pneumatic port with the second pneumatic port and to electrically connect the first electrical connector with the second electrical connector, the connector assembly including a pneumatic line, at least one electrical line, and a dual mode plug configured to permit connection of the pneumatic line with the second pneumatic connector substantially simultaneously with connection of the at least one electrical line with the second electrical connector.

10. The mattress system ofclaim 9, wherein the connector assembly includes a dual lumen hose having side-by-side first and second lumens, the first lumen serves as the pneumatic line for communication of pneumatic pressure from the second pneumatic port of the control unit to the at first pneumatic port of the mattress and the second lumen serves as an electrical conduit through which the at least one electrical line is routed.

11. The mattress system ofclaim 10, wherein a first end of the dual lumen hose is coupled to the dual mode plug, wherein the connector assembly has a pneumatic coupler mounted to the first lumen at a second end of the dual lumen hose, and wherein the at least one electrical line extends beyond the second lumen at the second end of the dual lumen hose.

12. The mattress system ofclaim 9, wherein the dual mode plug includes a plug housing and at least one latch member coupled to the plug housing, the at least one latch member being movable between a first position locking the dual mode plug to the main housing of the control unit and a second position unlocking the dual mode plug for detachment from the main housing of the control unit.

13. The mattress system ofclaim 12, wherein the at least one latch member is spring-biased toward the first position.

14. The mattress system ofclaim 12, wherein the at least one latch member comprise a pair of latch members, each situated on an opposite side of the plug housing.

15. The mattress system ofclaim 14, wherein the plug housing includes a pair of recesses and at least a portion of each latch member is received within a respective one of the pair of recesses.

16. The mattress system ofclaim 14, wherein the pair of latch members are movable toward the plug housing to move the pair of latch members between the respective first and second positions.

17. The mattress system ofclaim 9, wherein the dual mode plug includes a front wall, a pneumatic coupler extending away from the front wall, and an electrical coupler extending away from the front wall; wherein the pneumatic coupler is configured to mate with the second pneumatic port; and wherein the electrical coupler is configured to mate with the second electrical connector.

18. The mattress system ofclaim 17, wherein the pneumatic coupler is formed integrally with the front wall and the front wall has an aperture through which the electrical coupler extends.

19. The mattress system ofclaim 17, wherein the dual mode plug includes a check valve in communication with the pneumatic coupler.

20. A mattress system comprising

a mattress having at least one person support element,

a pressure sensor situated within an interior region of the mattress, the pressure sensor being situated beneath the at least one person support element and comprising an enclosure containing a liquid, and

circuitry that receives a signal from the pressure sensor and that determines, based on the signal, whether a bed exit condition has been detected.

21. The mattress system ofclaim 20, wherein the at least one person support element comprises at least one foam element.

22. The mattress system ofclaim 20, wherein the at least one person support element comprises a plurality of foam elements.

23. The mattress system ofclaim 20, wherein the at least one person support element comprises at least one foam element and at least one inflatable bladder.

24. The mattress system ofclaim 20, wherein the liquid contained in the enclosure comprises a silicon oil.

25. The mattress system ofclaim 20, wherein the liquid contained in the enclosure fills substantially all of an interior region of the enclosure.

26. The mattress system ofclaim 20, wherein the enclosure comprises a flexible bag.

27. The mattress system ofclaim 20, wherein the mattress further comprises an underlay that is situated beneath the at least one person support element and that has a space which receives the enclosure containing the liquid.

28. The mattress system ofclaim 20, wherein the circuitry includes a sound-producing device that is activated if the circuitry determines that a bed exit condition has been detected.

29. The mattress system ofclaim 20, wherein the circuitry is positioned within the mattress.

30. The mattress system ofclaim 20, further comprising a control unit having a housing spaced from the mattress, the circuitry is carried by the housing, and the pressure sensor is operably coupled to the circuitry.

31. The mattress system ofclaim 30, wherein the pressure sensor is operably coupled to the circuitry via at least one electrical line that extends from the mattress to the control unit.

32. The mattress system ofclaim 30, wherein the pressure sensor is operably coupled to the circuitry via a wireless coupling.

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