Abstract:
An electrical connector assembly includes a first connector subassembly associated with a removable component, and a second connector subassembly associated with a host component to which the removable component is removably connectable. One and only one of the first and second connector subassemblies is floatable relative to its associated component.

Description:
This application is a continuation of U.S. patent application Ser. No. 11/088,468, filed Mar. 24, 2005 now abandoned, which is a continuation of U.S. patent application Ser. No. 10/940,480, filed Sep. 14, 2004 now abandoned, which is a continuation of U.S. patent application Ser. No. 10/038,986, filed Nov. 19, 2001, now U.S. Pat. No. 6,791,460, which is a continuation of U.S. patent application Ser. No. 09/737,111, filed Dec. 14, 2000, now U.S. Pat. No. 6,320,510, which is a divisional of U.S. patent application Ser. No. 09/264,174, filed Mar. 5, 1999, now U.S. Pat. No. 6,208,250, the disclosures of which are expressly incorporated herein by reference. 
    
    
     BACKGROUND 
     Hospital beds typically include a footboard and a frame. The footboard is removably mounted to the frame adjacent a foot end of the frame. It may also be necessary to provide an electrical connection between electrical components associated with the frame and electrical components such as footboard mounted controls, associated with the footboard, and to do so in such a way that the mechanical connection of the footboard to the frame completes the electrical connection without further intervention by the user. However the mechanical alignment between the footboard and the frame may not be precise enough to properly align the electrical connectors of the footboard with those of the frame. Accordingly, it is desirable to provide an arrangement in which initial alignment between the footboard and frame is followed by further alignment of the electrical connectors on the footboard with those of the frame so that a satisfactory electrical connection naturally results from the mechanical connection of the footboard to the frame. 
     SUMMARY OF THE INVENTION 
     The present invention relates to patient supports such as hospital beds, carts, chairs, and stretchers. More particularly, the present invention relates to a removable footboard coupled to a patient support. 
     According to an illustrative embodiment of the present disclosure, a patient support includes a frame, a footboard removably connectable to the frame, a control panel coupled to the footboard, a first electrical connector, and a second electrical connector. The first electrical connector is located on the footboard and is operably coupled to the control panel. The second electrical connector is coupled to the frame. The second electrical connector is configured to couple to the first electrical connector when the footboard is coupled to the frame and decouple from the first electrical connector when the footboard is removed from the frame. 
     According to another illustrative embodiment of the present disclosure, a patient support includes a frame, a footboard, a control panel, a mounting assembly, a first electrical connector, and a second electrical connector. The control panel is coupled to the footboard. The mounting assembly is configured to couple the footboard to the frame. The first electrical connector is operably coupled to the control panel. The second electrical connector is operably coupled to a controller. The second electrical connector is configured to be removably connectable to the first electrical connector. 
     According to another illustrative embodiment of the present disclosure, a patient support includes a frame a footboard, a first electrical connector located on the footboard, a second electrical connector coupled to the frame, a first connector alignment apparatus, and a second connector alignment apparatus. The second electrical connector is configured to couple to the first electrical connector when the footboard is coupled to the frame and decouple from the first electrical connector when the footboard is removed from the frame. The first connector alignment apparatus has a connector receiving portion configured to secure the first electrical connector to the first connector alignment apparatus. The second connector alignment apparatus has a connector receiving portion configured to secure the second electrical connector to the second connector alignment apparatus. 
     According to another illustrative embodiment of the present disclosure, a patient support includes a frame, a footboard, a first electrical connector, and a second electrical connector. The footboard is removably connectable to the frame. The first electrical connector is located on the footboard. The second electrical connector is coupled to the frame. The second electrical connector is configured to couple to the first electrical connector when the footboard is coupled to the frame and decouple from the first electrical connector when the footboard is removed from the frame. 
     According to yet another illustrative embodiment of the present disclosure, a patient support includes a frame, a footboard, a power source, a control panel, a first electrical connector, and a second electrical connector. The footboard is removably connectable to the frame. The control panel is coupled to the footboard. The control panel includes at least one lockout switch configured to lockout at least one of a plurality of bed functions. The first electrical connector located on the footboard and is operably coupled to the control panel. The second electrical connector is coupled to the frame and is operably coupled to the power source. The second electrical connector is configured to couple to the first electrical connector when the footboard is coupled to the frame and decouple from the first electrical connector when the footboard is removed from the frame. The power source is configured to provide power to the control panel when the footboard is coupled to the frame. 
     Additional features and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of illustrated embodiments exemplifying the best mode of carrying out the invention as presently perceived. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The detailed description particularly refers to the accompanying figures in which: 
         FIG. 1  is a perspective view of a hospital bed which includes a patient position detection apparatus in accordance with the present invention and which includes a footboard having an electrical connector alignment apparatus of the present invention; 
         FIG. 2  is an end view of the footboard of  FIG. 1  illustrating further details of the electrical connector alignment apparatus; 
         FIG. 3  is an exploded perspective view of portions of the hospital bed of  FIG. 1  illustrating a base frame, a weigh frame, an intermediate frame, a retracting frame, an articulating deck, a first set of sensors for detecting the weight of a patient on the deck, and a second set of sensors located on the articulating deck for detecting the position of the patient on the deck; 
         FIG. 4  is a partial sectional view illustrating a load cell configured to connect the weigh frame to the base frame; 
         FIG. 5  is a perspective view of a head end siderail which includes a control panel for operating the patient position detection apparatus of the present invention; 
         FIG. 6  is an enlarged view of the control panel of  FIG. 5  which is used to control the mode of operation of the patient position detection apparatus and the volume of the alarms generated by the detection apparatus; 
         FIG. 7  is a block diagram illustrating the control electronics of the patient position detection apparatus; 
         FIG. 8  is a top plan view of the articulating deck of the bed with the second set of sensors mounted on the deck; 
         FIGS. 9 and 10  are flow charts illustrating a main loop of steps performed by the controller for monitoring inputs from the control panel and the first and second sets of sensors to control operation of the patient position detection apparatus in a position mode, an exiting mode, and an out-of-bed mode; 
         FIG. 11  is a flow chart illustrating steps performed by the controller in the position mode; 
         FIG. 12  is a flow chart illustrating steps performed by the controller in the exiting mode; 
         FIG. 13  is a flow chart illustrating steps performed by the controller in the out-of-bed mode; 
         FIG. 14  is a perspective view of a first electrical connector alignment apparatus configured to be coupled to the footboard of the bed; 
         FIG. 15  is a perspective view of a second electrical connector alignment apparatus configured to be coupled to the retracting frame of the bed; and 
         FIG. 16  is an exploded perspective view illustrating the first and second electrical connector apparatuses with electrical connectors installed therein and located on the footboard and retracting frame, respectively. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings,  FIG. 1  illustrates a hospital bed  10  of the present invention. The bed  10  includes a base frame  12  having a plurality of casters  14  and brake/steer control pedals  16  mounted adjacent each of the casters  14 . Details of the operation of the brake/steer control mechanism are disclosed in U.S. Pat. No. 6,321,878, entitled CASTER AND BRAKING SYSTEM, which is hereby incorporated by reference. 
     As best shown in  FIG. 3 , the bed  10  includes a weigh frame  18  coupled to the base frame  12 , an intermediate frame  19  coupled to the weigh frame  18 , a retracting frame  20  coupled to the intermediate frame  19 , and an articulating deck  22  coupled to the intermediate frame  19  and the retracting frame  20 . Brackets  21  on opposite sides of frame  20  are configured to be coupled between the head section  106  and the thigh section  110  of deck  22  with suitable fasteners (not shown). 
     Referring again to  FIG. 1 , the bed  10  includes a headboard  24  mounted adjacent a head end  26  of the bed  10  and a footboard  28  mounted to the frame  20  adjacent a foot end  30  of bed  10 . Bed  10  further includes a pair of head end siderails  32  and a pair of foot end siderails  34  mounted to the articulating deck  22  on opposite sides of the bed  10 . Further details of head end siderail  32  are illustrated in  FIG. 5 . Siderails  32  and  34  are coupled to the articulating deck  22  in a conventional manner using a connector mechanism  35  best shown in  FIG. 5 . The siderails  32  and  34  are movable from a lowered position shown in  FIG. 1  to an elevated position (not shown) located above a top surface  36  of mattress  38 . Mattress  38  is located on articulating deck  22  for supporting a patient thereon. 
     The footboard  28  includes a plurality of buttons, knobs, switches or other controls  40  for controlling various functions of the bed  10 . Controls  40  are located on a top inclined panel  42  and a bottom inclined panel  44  on the footboard  28 . A cover  46  is pivotably coupled to the footboard  28  by a pivot connection  48  so that the cover can be pivoted downwardly to conceal at least the controls  40  located on the top inclined panel  42 . 
     One of the controls on the footboard  28  is illustratively a lockout button  61  for entertainment functions which are controlled by patient input control panels on the bed  10 . In other words, a caregiver can press button  61  to lock out entertainment functions on the bed  10 . An indicator light is provided adjacent the entertainment lockout control  61  to provide an indication when the entertainment lockout  61  is activated. When the entertainment lockout  61  is activated, the patient cannot turn on the television, radio, stereo, video player, computer or other entertainment device typically available on the bed or in the room. The entertainment lockout control  61  is illustratively located below the cover  46  on the footboard  28 . It is understood, however, that the entertainment lockout may be located at other positions on the bed. 
     The bed  10  also includes a plurality of lockout switches  63  which are illustratively located on the footboard  28 . It is understood that the lockout switches  63  may be located at any other position on the bed  10 . The lockout switches  63  are coupled to the controller  50  to permit a caregiver to lock out selected functions which are normally controlled by the patient. Using patient controls that are typically located on the head end siderails  32 . For example, lockout switches  63  may deactivate controls for a night light, a back light, head or knee articulation, a hi/lo mechanism, or the entertainment devices discussed above. In addition, a master lockout switch is provided to lock out the head and knee articulation and the hi/lo control mechanism controls. 
     Panel  42  illustratively includes an indicator light (not shown) adjacent each of the lockout switches  63  to provide an indication when a particular lockout switch  63  is pressed. In addition, the bed  10  includes a separate lockout indicator light  65  located at a location on the bed  10  spaced apart from the lockout switches  63 . In the illustrated embodiment, the separate lockout indicator light  65  is located on the head end siderail  32  as shown in  FIG. 5 . Indicator light  65  provides the nurse with a visual indication that one of the lockout switches  63  has been pressed. 
     Footboard  28  also includes side bumpers  66  and apertures  68 . Apertures  68  provide handles to facilitate movement of the bed  10 . Illustratively, headboard  24  and footboard  28  are made from a plastic material using a blow molding process. It is understood, however, that the headboard  24  and footboard  28  may be made from other materials and from other processes, if desired. 
     The controls  40  on the footboard  28  are electrically coupled to a controller  50  shown in  FIG. 3 . The controller  50  and other bed electronics are illustratively mounted on frame  20 . A first connector alignment apparatus  52  is coupled to the footboard  28  and a second connector alignment apparatus  54  is coupled to the frame  20 . As shown in  FIGS. 2 and 3 , footboard  28  is formed to include apertures  56  which slide over posts  58  on the frame  20  during installation of the footboard  28  onto the frame  20  in the direction of arrow  60  in  FIG. 3 . Posts  58  and apertures  56  therefore provide initial alignment between the footboard  28  and the frame  20 . First and second connector alignment apparatuses  52  and  54  provide further alignment for male and female electrical connectors  62  and  64 , respectively, as discussed in detail below with reference to  FIGS. 14-16 . 
     The patient position detection apparatus of the present invention uses two different types of sensors  70 ,  104 . A first set of sensors  70  is used to detect when a patient exits the bed  10 . A second set of sensors  104  is used to determine a position of the patient on the deck  22  of the bed  10 . In the illustrated embodiment, the first type of sensors include load cells  70  which are mounted at the four corners of the weigh frame  18 . Details of the mounting of the load cells  70  between the base frame  12  and the weigh frame  18  are illustrated in  FIGS. 3 and 4 . Base frame  12  includes side frame members  72  and transverse frame members  74  extending between the side frame members  72 . Weigh frame  18  includes a pair of hollow side frame members  76 . Load cells  70  are well known. Load cells  70  typically include a plurality of strain gauges located within a metal block. 
     As best shown in  FIG. 4 , a mounting ball  78  is coupled to the load cell  70 . Illustratively, mounting ball  78  includes a threaded stem which is screwed into threads in the load cell  70 . Mounting ball  78  is located within an aperture  80  formed in a mounting block  82 . Mounting blocks  82  are secured to the transverse frame members  74  by suitable fasteners  84  at the four corners of the base frame  12 . A mounting bar  86  is coupled to an arm  88  of load cell  70  by fasteners  90 . Mounting bar  86  is then secured to a top surface  92  of side frame member  76  of weigh frame  18  by suitable fasteners  94  and washers  96 . Mounting bar  86  is not coupled to arm  98  of load cell  70 . Therefore, load cell  70  may be deflected downwardly in the direction of arrow  100  when weight is applied to the weigh frame  18 . Such deflection in the direction of arrow  100  changes an output voltage which provides an indication of weight change on the weigh frame. Load cells  70  are coupled to a signal conditioner  53  by wires  102 . The signal conditioner  53  is then coupled to the controller  50  on the bed  10  by wires  102 . 
     Although the specification and claims of this application refer to a controller  50 , it is understood that the bed  10  will typically include several controllers which control different functions on the bed. These controllers may be located at any location on the bed and are not limited to the location illustrated in  FIG. 3 . The controllers  10  typically are microprocessor based controllers. Output signals from various devices may need to be conditioned prior to being coupled to the controller. For instance, analog signals may need to be converted to digital signals for processing by the microprocessor of the controller. Therefore, the word controller is used broadly to include any type of control circuitry necessary to process the output signals and produce the desired control outputs or signals. 
     A second set of sensors  104  is illustrated in  FIGS. 3 and 8 . Articulating deck  22  includes a head deck section  106 , a seat deck section  108 , a thigh deck section  110 , and a leg deck section  112 . The second set of sensors  104  includes a head section sensor  104  coupled to head deck section  106  by fasteners  116 . Sensor  114  is elongated and extends along a longitudinal axis  118  of the deck  22 . Seat sensor  120  is coupled to seat deck section  108  by fasteners  116 . Sensor  120  extends in a direction transverse to the longitudinal axis  118 . Thigh sensors  122  and  124  are coupled to thigh deck section  110  by fasteners  116 . The locations of sensors  114 ,  120 ,  122 ,  124  are further illustrated in  FIG. 8 . 
     Illustratively, sensors  114 ,  120 ,  122 , and  124  are resistive pressure sensors available from Interlink Electronics. The resistive pressure sensors are formed in strips which can be cut to any desired length. The sensor strips are illustratively adhered to a stiffener and then sealed within a protective outer sleeve or cover made from a wipeable material. Fasteners  116  are illustratively rivets which secure the sensors  114 ,  120 ,  122 , and  124  in position on the deck  22  as best shown in  FIG. 8 . Sensors  114 ,  120 ,  122 , and  124  are coupled to the controller  50  on the bed  10  by wires  126 . 
     As pressure on the sensors  114 ,  120 ,  122 , and  124  increases, resistance of the sensors is lowered. By processing the output signals from sensors  114 ,  120 ,  122 , and  124 , the controller  50  determines the position of the patient on the deck  22 . In particular, the controller  50  determines when the patient moves away from a central portion of the bed and too close to the side edges  23  or  25  on the deck  22 . Controller  50  then provides an indication that the patient is at risk of exiting the bed. 
     Using the two different types of sensors  70  and  104 , the patient position detection apparatus of the present invention is capable of operating in several different modes to assist the caregiver with tracking the patient position on the bed  10 . In an out-of-bed mode, only sensors  70  are used to activate an alarm when a patient completely exits the bed. In a second exiting mode, both sets of sensors  70 ,  104  are used. An alarm is activated when a patient is located at a position near the sides  23 ,  25  of deck  22  or on the deck  22  near the head end  26  or foot end  30 . In other words, a pre-exit alarm is sounded when the patient moves outside a central portion of the deck  22  on the bed  10 . In a third position mode, both sets of sensors  70 ,  104  are also used. An alarm is activated when a patient moves away from the head sensor  114  on the deck  22  as discussed below. 
       FIG. 7  is a block diagram illustrating the electronic control components of the patient position detection apparatus. As discussed above, the first and second sensors  70  and  104  are each coupled to the controller  50 . The controller  50  processes signals from the first and second sensors  70 ,  104  as discussed in detail below to provide various control functions. A caregiver control panel  130  is mounted on the bed  10  to control operation of the patient position detection apparatus. Preferably, the caregiver control panel  130  is mounted on the head end siderail  52  as best shown in  FIG. 5 . The control panel  130  may also be on a pendant or on a remote control device electrically coupled to the controller  50 . The caregiver control panel  130  includes control buttons, switches, knobs, etc. for setting the particular type of tone for the audible alarm and for setting a volume of the alarm for each of the detection modes as illustrated at block  132 . In addition, the caregiver control panel  130  includes control buttons, switches, knobs, etc. to set the particular type of detection mode for the apparatus as discussed below. Inputs from the caregiver control panel  130  are transmitted to the controller  50 . Controller  50  also transmits signals to the caregiver control panel  130  to control indicator lights  136  on the caregiver control panel  130 . 
     If an alarm condition is detected by controller  50  as discussed below in detail, controller  50  controls either audible or visual local alarms  138  within the room or on the bed  10 . Controller  50  may also be used to turn on the room lights  140  when an alarm condition is detected. Finally, the controller  50  activates a nurse call alarm  142  to send an indication of the alarm condition to a nurse station located at a remote location. 
     The apparatus of the present invention further includes a nurse call reset or clear button  144  located on the bed  10 . This clear button  144  sends a signal to controller  50  to clear the nurse call  142  alarm once the nurse call  142  alarm has been activated at the remote nurse call station. Nurse call clear button  144  permits the caregiver to clear or reset the remote patient alarm while at the bed  10  after responding to the alarm condition. Currently, caregivers must cancel the nurse call bed exit alarm  142  by returning to the nurse call station or by deactivating the alarm somewhere else in the hospital, other than at the bed  10 . Button  144  permits the caregiver to clear the nurse call bed exit alarm  142  after responding to the alarm condition at the bed  10 . Controller  50  is also coupled to a communication network  55  so that the controller  50  can transmit output signals to a remote location. 
     In an alternative embodiment of the present invention, controller  50  is programmed to deactivate the local alarm  138  if the patient returns to bed  10  or returns to a correct position on the bed  10  depending upon the mode selected. This feature may encourage the patient to return to the correct position on the bed  10  since the alarm will be deactivated when the patient returns to the correct position. The nurse call alarm  142  typically remains activated so that the caregiver may still respond to the alarm, even if the local audible and visual room alarm  138  is deactivated. 
       FIG. 6  illustrates further details of the caregiver control panel  130  which is illustratively located on the head end siderail  132 . Control panel  130  includes a key button  150 , a mode control button  152 , and a volume control button  154 . In order to adjust the detection mode or volume of the alarm, the caregiver must depress the key button  150  and hold it down while depressing the desired mode button  152  or volume button  154 . With the key button  150  held down, the caregiver can scroll through the modes of operation by pressing the mode button  152 . Separate indicator LEDs are provided to indicate which mode is selected. The Position Mode is indicated by LED  156 , the Exiting Mode is indicated by LED  158 , and the Out-of-Bed Mode is indicated by LED  160 . If none of the LEDs  156 ,  158 ,  160  is lit, the patient position detection apparatus is off. 
     If the Position Mode is selected, all three LEDs  156 ,  158 , and  160  are lit. If the Exiting Mode is selected, LEDs  158  and  160  are lit. If the Out-of-Bed Mode is selected, only LED  160  is lit. By providing a different number of indicator lights for each of the three modes, a caregiver can tell which mode is selected in the dark. 
     By requiring the depression of both the key button  150  and the mode button  152  or volume button  154  and by placing these buttons  150 ,  152 ,  154  on the caregiver side of the siderail  32 , the patient is deterred from changing modes or volumes. The caregiver can change the volume of the alarm between a high setting, a medium setting, and a low setting by pressing the key button  150  and simultaneously pressing the volume button  154 . Subsequent presses of the volume button  154  change the volume to different levels. Indicator LEDs  162 ,  164 , and  166  are provided for the high, medium, and low volumes, respectively. If the high volume level is selected, all three LEDs  162 ,  164 , and  168  are lit. If the medium volume level is selected, LEDs  164  and  168  are lit. If the low volume level is selected, only LED  168  is lit. By providing a different number of indicator lights for each volume level, a caregiver can tell the volume level for the alarm in the dark. When the patient position detection apparatus is off, all the volume LEDs  162 ,  164 , and  168  are off. 
     When a local alarm condition is detected by controller  50  as discussed below. An appropriate LED for Position Mode, Exiting Mode, and Out-of-Bed Mode will flash on the control panel  30  to indicate an alarm condition for that mode. More than one of the LEDs  156 ,  158 , and  160  can flash. For instance, in Position Mode, the Position Mode LED  156  may begin to flash when an alarm condition is detected by the Position Mode. Since the Out-of-Bed Mode is also run in Position Mode, the Out-of-Bed LED  160  may also be flashing if the patient has exited the bed. 
     Caregiver control panel  130  also includes an indicator LED  170  to provide an indication that the bed  10  is not down. This indicator LED  170  is lit when the deck  22  is not in its lowest position relative to the floor. In addition, caregiver panel  130  includes an indicator LED  172  which provides an indication when the brake on the casters  14  is not set. When positioned in a room, the bed  10  is typically set so that the deck  22  is in its lowest position and the brake is set. Therefore, indicator LEDs  170  and  172  provide the caregiver with an indication that these conditions are not met. 
       FIG. 8  shows the illustrative arrangement of the sensors  114 ,  120 ,  122 , and  124  on the articulating deck  22 . It is understood that other arrangements of the second set of sensors  104  may be used in accordance with the present invention. In addition, additional sensors may be provided such as a sensor  125  located on the leg deck section  112 . Although the second sensors  104  are illustratively resistive sensors, it is understood that other types of sensors may be used in accordance with the present invention. For example, capacitance sensors such as shown in U.S. Pat. No. 5,808,552 or in U.S. Pat. No. 6,067,019, which are incorporated herein by reference, may be used as the second sensors. In addition, a piezoelectric sensor such as disclosed in U.S. Pat. No. 6,252,512, filed Mar. 5, 1999, entitled A MONITORING SYSTEM AND METHOD, which is hereby incorporated by reference may also be used. In another embodiment, the sensors  104  are coupled to a stop or bottom surface of the mattress  38  or are located within an interior region of the mattress  38 . 
       FIGS. 9-12  are flow charts illustrating operation of the controller  50  of the present invention and each of the three patient position detection modes. The main software loop of the controller  50  is illustrated in  FIGS. 9 and 10 . The main loop begins at block  200  of  FIG. 9 . Controller  50  first updates the status of the indicator lights  136  on control panel  130  or elsewhere as illustrated at block  202 . Controller  50  then determines whether the patient detection system is on at block  204 . If the detection system is not on, controller  50  advances to block  230  as illustrated at block  205 . If the patient detection system is on, controller  50  checks the mode of the detection system as illustrated at block  206 . Specifically, controller  50  determines whether the detection system is in position mode as illustrated at block  208 , exiting mode as illustrated at block  210 , or out-of-bed mode as illustrated at block  212 . 
     If the controller is in position mode as illustrated at block  208  or exiting mode as illustrated at block  210 , the controller  50  will run the control loops for these modes as discussed below. After running the positioning mode loop or the exiting mode loop, the controller  50  will also run the out-of-bed mode loop when the controller is set in position mode or exiting mode. In other words, if the detection system is on, the out-of-bed mode will always be checked. 
     Controller  50  then determines whether the mode was just activated at block  214 . If the particular mode was not just activated, the controller  50  advances to block  246  of  FIG. 11  if the system is in position mode as illustrated at block  216 . If the particular mode was not just activated, controller  50  advances to block  264  of  FIG. 12  if the system is in exiting mode as illustrated at block  218 . If the particular mode was not just activated, controller  50  advances to block  278  of  FIG. 13  if the system is in out-of-bed mode as illustrated at block  220 . 
     If the mode was just activated at block  214 , controller  50  reads all the sensor values from the first and second sets of sensors  70  and  104  as illustrated at block  222 . Controller  50  then determines whether the sensor values are within the preset specifications as illustrated at block  224 . In the position mode, controller  50  is only concerned with the head sensor  114 . Therefore, in position mode, the output from head sensor  114  is checked. The output value from sensor  114  is within specification if the head sensor  114  output signal corresponds to a range of weights between 50-450 lbs. Therefore, for position mode, the sensor  114  is typically not within specification if the head sensor  114  is not plugged in, shorted, or if a patient is not on the bed  10 . 
     For exiting mode, controller  50  checks all the load cells  70  and sensors  114 ,  120 ,  122 , and  124 . To be within specification for exiting mode, the weight range detected by load cells  70  must be within a predetermined range based on average human weights. Controller  50  also determines whether any of the sensors  114 ,  120 ,  122 , or  124  are not plugged in or are shorted. In the out-of-bed mode, controller  50  only looks at load cells  70  to make sure that at least a predetermined minimum weight reading is obtained in order to indicate that a patient is on the bed  10 . 
     If the values read at block  222  are not within specifications, controller  50  will send a local alarm as illustrated at block  226  so that the caregiver can investigate the problem as illustrated at block  226 . Controller  50  then turns the detection system off as illustrated at block  227  and advances to block  230  as illustrated at block  229 . If the retrieved sensor values are within the specifications at block  224 , controller  50  stores all the sensor values in memory  51  as illustrated at block  228 . Controller  50  then advances to block  230  as illustrated at block  229 . 
     In the illustrated embodiment, the key button  150  on control panel  130  is a hardware switch. If the key button  50  is not pressed, the controller  50  does not receive the signal from the mode button  152  or the volume button  154 . Therefore, if the key button is not pressed as illustrated at block  232 , controller  50  returns to block  200  as illustrated at block  244 . If the key button  150  and the mode button  152  are pressed as illustrated at block  234 , the controller  50  will receive an input based on the mode button press. If the key button  150  and the volume button  154  are pressed as illustrated at block  236 , the controller  50  will receive an input signal from the volume button  154  press. If the key button  150 , the mode button  152 , and the volume button  154  are all pressed as illustrated at block  238 , the controller  50  will receive input signals from both the mode button press and the volume button press. If the key button and at least one other button are pressed at blocks  234 ,  236 , and  238 , controller  50  will update the mode and volume settings in memory  51  as illustrated at block  240 . Controller  50  then returns to block  200  as illustrated at block  244 . 
     Operation of the controller  50  in position mode is illustrated beginning at block  246  of  FIG. 11 . Controller  50  first reads the current value of head sensor  114  as illustrated at block  248 . The current head sensor value is abbreviated as CV. Next, controller  50  retrieves the stored value for head sensor  114  which was stored in memory  51  at block  228  as illustrated at block  250 . The stored sensor value is abbreviated as SV. Controller  50  then determines a scaler value based upon the stored head sensor value. In the illustrated embodiment, an 8 bit A/D converter is used to convert the output from the sensors  104 . Therefore, the value SV ranges from 1-256 in the illustrated embodiment. Smaller values of SV indicate larger weight on the sensors  104 . It is understood that this range could be varied depending upon the particular A/D converter used. Therefore, the range of 1-256 is only for illustrative purposes. Controller  50  sets the scaler value as illustrated in the table at block  252 . The scaler value remains constant until the mode is reactivated. Next, controller  50  calculates the acceptable range for the current head sensor value (CV) as illustrated at 
     Install Equation Editor and double-click here to view equation. 
     block  254 . The acceptable range is: 
     Controller  50  determines whether the current head sensor value CV is within the acceptable range as illustrated at block  256 . If so, controller  50  determines that the patient is in the proper position on the deck and returns to block  230  as illustrated at block  262 . If the current head sensor value is not within the acceptable range at block  256 , controller  50  determines whether a timer has expired at block  258 . If not, controller  50  advances back to block  230 . If the timer has expired, controller  50  determines that the patient is out of position and activates the local alarms  138  as illustrated at block  260 . Controller  50  also activates a nurse call alarm  142 , and may turn on the room lights  140  at block  260 . Controller  50  then advances to block  278  and runs the out-of-bed mode check as illustrated at block  262 . 
     Operation of the patient detection system in exiting mode is illustrated beginning at block  264  in  FIG. 12 . Controller  50  advances to block  264  from block  218  in  FIG. 9 . In exiting mode, controller  50  first runs the positioning mode loop as illustrated at block  266 . In other words, the controller  50  uses head sensor  114  to check the patient&#39;s position using the flow chart discussed above in reference to  FIG. 11 . Controller  50  determines whether the current head sensor value CV is within the acceptable range as illustrated at block  268 . If so, controller  50  determines that the patient is in the proper position and advances to block  278  to run the out-of-bed mode check as illustrated at block  276  in  FIG. 12 . 
     If the head sensor value is not within the acceptable range at block  268 , controller  50  runs a sensor test for seat sensor  120  and thigh sensors  122  and  124  using a similar test as in  FIG. 11 . Scaler values may be adjusted for the different sensors  120 ,  122 , and  124 , if necessary. Scaler values are selected by applying a known load above a particular sensor location and taking an output reading. Next, a predetermined distance from the sensor is selected at which point it is desired to activate the alarm. The known weight is than moved to that desired alarm location and another output reading is taken. The scaler value is calculated the percentage change between the output of the sensor when the known weight applied directly over the sensor and the output of the sensor when the known weight applied at the predetermined distance perpendicular to the sensor. 
     Controller  50  then determines whether two of the three remaining sensors  120 ,  122 , and  124  are within acceptable ranges as illustrated at block  272  by comparing the current sensor values to ranges based on the corresponding stored sensory values. If so, controller  50  determines that the patient is in an acceptable position on the deck  22  and advances at block  230  as illustrated at block  276 . If two of the three sensors are not within the acceptable ranges at block  272 , controller  50  determines that the patient is out of position and updates the local alarms  238 , activates the nurse call alarm  142 , and may turn on the room lights  140  as illustrated at block  274 . Controller  50  then advances to block  230  as illustrated at block  276 . In exiting mode, the patient position detection apparatus of the present invention permits the patient to move around more on the deck  22  before an alarm is activated compared to the position mode. Therefore, position mode is the most sensitive setting for the patient position detection apparatus of the present invention. 
     It is understood that other configurations may be provided for the locations of sensors  104 . A different number of sensors  104  may be used. The sensors  104  may be mounted at different locations on the deck  22 , on the mattress  38 , or elsewhere on the bed  10 . 
     Operation of the patient position detection system in the out-of-bed mode is illustrated beginning at block  278  in  FIG. 13 . Controller  50  advances to block  278  from block  220  in  FIG. 9 . In the out-of-bed mode, controller  50  detects an average current weight of the patient as illustrated at block  280 . For instance, the controller  50  can take four readings from each load cell  70  and divide by four to get an average current weight. Next, controller  50  retrieves the stored initial weight from memory  51  as illustrated at block  282 . Controller  50  subtracts the stored weight from the current weight as illustrated at block  284 . 
     Next, controller  286  determines whether the weight on the bed  10  detected at block  280  has increased or decreased by more than 30 lbs. compared to the initial stored weight retrieved at block  282 . If the weight has not changed by more than 30 lbs., controller returns to block  230  as illustrated at block  294 . If the weight has changed by more than 30 lbs. at block  286 , controller  50  determines whether a timer has expired at block  288 . If the timer has not expired, controller  250  advances to block  230  as illustrated at block  294 . If the timer has expired at block  288 , the controller  50  determines whether the difference calculated at block  284  is less than −30 lbs. at block  290 . If so, controller  50  determines that the patient has exited the bed  10  and updates the local alarms  138 , the nurse call alarm  142  and may turn on the room lights  140  as illustrated at block  292 . Controller  50  then returns to block  230  as illustrated at block  294 . 
     If the difference is not less than −30 lbs. at block  290 , controller  50  determines whether the difference calculated at block  284  is greater than 30 lbs. as illustrated at block  296 . If so, controller  50  determines that substantial additional weight has been added to the bed and updates local alarms  138  only as illustrated at block  298 . The nurse call alarm  142  may also be activated, if desired. Controller  50  then advances to block  230  as illustrated at block  294 . If the difference is not greater than 30 lbs. at block  296 , controller  50  clears the local alarm only at block  300  and then advances to block  230  as illustrated at block  294 . 
     It is understood that the 30 lbs. threshold value for the out-of-bed mode may be adjusted upwardly or downwardly depending upon the weight of the patient. In other words, if the patient is particularly heavy, the 30 lb. threshold may be increased, for example. 
     It is understood that the patient detection apparatus of the present invention may have more than three modes of operation if desired. The separate modes may have different sensitivity levels. 
     The out-of-bed mode of the present invention may be armed with the patient in the bed  10 . In some beds having scales, the patient must be removed in order to determine a tare weight of the bed prior to the patient getting into the bed in order to arm the bed exit detector. In the out-of-bed mode of the present invention, removing the patient from the bed is not required in order to arm the bed exit detection system. 
     The patient position detection system of the present invention may be quickly switched from a normal bed exit system in which an alarm is generated only when a patient exits the bed to a predictive bed exit system in which an alarm is generated when a patient moves away from a center portion of the bed. In an embodiment of the invention, the output signals from the first and second set of sensors  70 ,  104  are monitored and stored, either at the bed  10 , or at a remote location to record movements of the patient. The controller  50  or a controller at the remote location monitors the sensor output values to determine whether the patient is moving on the bed  10 . In one embodiment, the controller  50  or controller at a remote location generates a caregiver alert signal or alarm if the patient has not moved on the bed within a predetermined period of time. Therefore, the caregiver can go to the bed  10  and rotate the patient in order to reduce the likelihood that the patient will get bed sores. For example, if the patient hasn&#39;t moved for a predetermined period of time, such as two hours, a signal is generated advising the caregiver to move the patient. If the sensors  70 ,  104  and controller detect that the patient has moved within the predetermined period, then there is no need for the caregiver to go turn the patient. Therefore, no signal is generated. This feature saves caregiver time and reduces the likelihood of injuries due to unnecessary rotation of a patient who has been moving. 
     In another embodiment of the present invention, the output signals from the four sensors  70  located at the corners of the base frame  12  are used to provide an indication when one of the frames or the deck hits an obstruction when moving from the high position to a low position. In particular, the processor  50  determines when an output signal from one of the sensors  70  at the corners generates a negative value or a greatly reduced weight reading within a short period of time. This rapid change in the output signal indicates that an obstruction has been hit. Therefore, controller  50  can provide an output signal to stop the hi/lo mechanism from lowering the frames and deck. An alarm signal is also provided, if desired. 
     In another embodiment of the present invention, the controller  50  is configured to transmit data to a nurse station located at a remote location over the communication network  55 . This data illustratively includes information related to at least one of patient weight, the patient&#39;s position on the support surface of the bed  10 , a bed exit indicator, the mode of operation of the patient position detection apparatus, a brake not set indicator, a bed not down indicator, or other data related to the status of the bed or the status of the patient. This permits the nurse to detect the information related to the status of the bed or the status of the patient at the central nurse station without having to check each bed separately. 
       FIGS. 14-16  further illustrate the connector alignment apparatus of the present invention. The first connector alignment apparatus  52  is illustrated in  FIG. 14 , the second connector alignment apparatus  54  is illustrated in  FIG. 15 . Connector alignment apparatus  52  is configured to receive a first pair of electrical connectors  62  shown in  FIG. 16  which include a housing  304  having a first pair of spaced-apart flanges  306  and a second pair of spaced-apart flanges  308 . Flanges  308  are each formed to include an aperture  310 . Connectors  302  include a plurality of electrical terminals  312  extending away from housing  304 . Alignment posts  313  extend from housing  304  of connector  62  further than terminals  312 . The terminals  312  are electrically connected to conductors of a cable  314 . Cable  314  of connectors  62  are connected to controls  40 . Connector alignment apparatus  54  is configured to receive female electrical connectors  64 . Those numbers referenced by numbers on connectors  62  perform the same or similar function. Connectors  64  include female socket contacts  318  configured to receive terminals  312  of connector  302 . Illustratively, cables extending from connectors  64  are coupled to the controller  50  on bed  10 . 
     Referring now to  FIG. 14 , connector alignment apparatus  52  includes a base plate  320  having outwardly extending alignment posts  322  located at opposite ends. Posts  322  each include tapered head portions  324 . Alignment apparatus  52  includes a pair of connector receiving portions  326 . Connector receiving portions  326  each include a pair of center posts  328 . Each post  328  includes a pair of spring arms  330 . Each spring arm  330  has a head portion  332  including a ramp surface  334  and a bottom lip  336 . Each connector receiving portion  326  also includes a pair of posts  338 . 
     Electrical connectors  62  are installed into the connector receiving portions  326  by locating the apertures  310  on flanges  308  over the posts  338  and pushing the connector  62  toward base  320 . Flanges  306  engage ramp surfaces  334  of heads  332  and cause the spring arms  330  to be deflected. Once the flanges  306  move past the heads  332 , heads  332  then move over flanges  306  to retain the connectors  302  within the connector alignment apparatus  52  as best shown in  FIG. 16 . 
     Second connector alignment apparatus  54  is best illustrated in  FIG. 15 . The alignment apparatus includes a body portion  340  having a pair of downwardly extending alignment posts  342 . Body portion  340  is formed to include apertures  344  at opposite ends. Apertures  344  are configured to receive the posts  322  of first connector alignment apparatus  52  as discussed below. Lead-in ramp surfaces  346  are formed around the apertures  344 . Body portion  340  further includes a pair of connector receiving portions  348  which function the same as connector receiving portions  326  described above. Reference numbers the same as in  FIG. 14  perform the same or similar function. Apertures  310  formed in flanges  308  of connectors  64  are inserted over the posts  338  of the connector receiving portions  348 . The connectors  64  are then pushed downwardly to deflect the heads  332  until the lips  336  move over flanges  306  to lock the connectors  64  within the housing  340  as discussed above. 
     The first connector alignment apparatus  52  and the second connector alignment apparatus  54  each may include a key shown diagrammatically at locations  349  and  351 , respectively. Certain beds have different features which are controlled by controller  50  and actuated by controls  40  on the footboard. Therefore, different footboards  28  may be required depending upon the particular type of bed  10  being used. The keys  349  and  351  on the first and second connector alignment apparatuses  52  and  54  only permit connection between an appropriate type of footboard  28  for the particular bed  10 . Therefore, the keys  349  and  351  ensure that the right type of footboard  28  is attached to the bed  10 . 
     First connector alignment apparatus  52  is rigidly coupled within a recessed portion  350  formed in footboard  28  as best shown in  FIG. 16 . The base  320  is secured to the footboard  28  by a fastener  352  which extends through an aperture  354  formed in the base  320 . The second connector alignment apparatus  54  is loosely connected to an end surface  356  of the frame  20 . A fastener  358  is configured to extend through an oversized central opening  360  formed in housing  340 . Posts  342  at opposite ends of the housing  340  are located within apertures  362  formed in the surface  356  of the frame  20 . Housing  340  is therefore not rigidly coupled to frame  20  and can float slightly due to the oversized apertures  362  and the oversized aperture  360 . 
     During installation of the footboard  28  on to the frame  20 , initial alignment is provided by posts  58  on frame  20  extending into the apertures  56  formed in the footboard  28 . As the footboard  28  moves downwardly over the posts  58 , the posts  322  on first connector alignment apparatus  52  enter the apertures  344  in the second connector alignment apparatus  54 . Tapered surfaces  324  on posts  22  and tapered surfaces  346  of apertures  344  facilitate insertion of the posts  322  into the apertures  344 . Since the housing  340  of second connector alignment apparatus  54  can float on the frame  20 , the housing  340  moves into proper alignment with the first connector alignment apparatus  52  as the footboard  28  is installed. This ensures proper alignment between connectors  62  and  64 . Typically, connectors  62  and  64  include further alignment posts  313  and apertures  315 , respectively, which mate to make sure that each of the terminals  312  line up with the socket contacts  318 . Therefore, the connector alignment apparatus of the present invention includes a combination of posts  58  on the frame  20  which mate with aperture  56  on the footboard  28 , posts  322  on the first connector alignment apparatus  52  which mate with apertures  344  on the second connector alignment apparatus  54 , and posts  313  on connectors  62  which mate with apertures  315  on the connectors  64  to provide further alignment. 
     Although the invention has been described in detail with reference to certain illustrated embodiments, variations and modifications exist within the scope and spirit of the invention as described and as defined in the following claims.