Abstract:
The invention is a Bed Exit Night Light System designed to illuminate a hospital room if a patient leaves his bed, but is not activated by the presence of hospital staff or casual movement of equipment.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    None. 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT 
       [0002]    None. 
       THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT 
       [0003]    None. 
       INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC 
       [0004]    None. 
       BACKGROUND OF THE INVENTION 
       [0005]    1. Field of the Invention 
         [0006]    The invention concerns hospital bedroom lighting. 
         [0007]    2. Background Art 
         [0008]    Hospitalized patients often struggle when they waken in unfamiliar rooms, and can hurt themselves by attempting to navigate in the dark. The industry has a variety of lighting systems to handle this challenge, none of which provide a satisfactory solution, as follows. 
         [0009]    U.S. Pat. No. 6,234,642 discloses a solution in which a lighting system is added to a bed&#39;s undercarriage, that illuminates the area around the edge of the bed. The lighting function of this product is designed for use primarily in multi-bed hospital patient rooms, and therefore the light only illuminates the area under the edge of the bed, so as not to disturb other patients in the room. 
         [0010]    The dim, narrowly focused light does not illuminate enough of the room to allow the patient to safely navigate their way to and from the restroom at night, which is how and why most patient falls within a hospital occur. Moreover, a hospital must buy the specific bed model that has the lights installed in order to gain the benefit of the light associated with the bed. There is no capability to use this product to retrofit existing beds. 
         [0011]    U.S. Pat. No. 5,600,305 discloses a bed-exit sensing system that employs an infrared sensor been that sits low near the bed and parallel to the bedside to detect a patient leaving the bed. 
         [0012]    This system has many problems. Modern hospital beds that have integral bed exit-sensing have made this system obsolete. Since a patient could potentially exit the bed from either side, it appears that two of the systems would be necessary, or at least the system would have to be changed from one side to the other. 
         [0013]    This system also is duplicative of modern hospital beds, which tend to have an integral patient-detection signal that can be used for any purpose, and makes the signal system irrelevant. And finally, the IR beam will be interrupted as hospital staff move within the room and equipment is moved within the room, as electric cables and signal wires are repositioned. This movement will create false positive signals of patient movement. Movement of equipment will cause the system sensors to require frequent realignment. 
         [0014]    The system does have a light that is mounted to the “Master Unit” that, according to the Abstract, sits on the patient floor, but with all of the false alarms that this system is bound to generate, the light would be on almost constantly and if bright enough to be effective, would keep the patient awake. 
         [0015]    U.S. Pat. No. 5,471,198—This patent discloses a bed-mountable system that senses the presence or absence of a patient by using a reflected electromagnetic beam. It includes an output relay that “may alternatively operate an alarm bell or light to indicate the absence of the patient”. In this case, the implication is that the “light” is intended to be an indicator light to alert staff, similar to the way a nurse call corridor light indicates an active call. It does not, in and of itself, include any kind of lighting to illuminate the patient room. 
         [0016]    The ability to detect the presence of a patient in a hospital bed has been perfected by bed manufacturers. This patent is still valid, but irrelevant to today&#39;s hospital beds, which routinely come with patient detection systems. 
         [0017]    U.S. Pat. No. 4,067,005—This patent discloses a “patient exit” signal, in which pressure sensors are mounted to the bed side rails. The signals are intended to detect when the patient is attempting to exit the bed and “sound a buzzer, and/or a call bell, and/or illuminate the bed so that a nurse or attendant is amply alerted . . . ” 
         [0018]    Once again, as in above patents and current products, the purpose is to illuminate only the bed itself to alert staff. It is not intended to illuminate the room. Other obvious problems are that the patient may accidently set the system off by grabbing the side rail when they are attempting to simply change their position in the bed; visitor and staff may set it off by leaning over the side rail to tend to the patient or lower it. Multiple false alarms tend to cause the staff to ignore all alarms. 
         [0019]    These patents summarize the prior art, which focuses on ways of detecting the presence of patients in beds, a task easily handled by modern hospital beds. The hospital bed industry needs a system that will assist hospitalized patients by lighting rooms only when patients leave their beds, does not light the room unduly by activating without false positives and does not create a need for hospital staff to modify their everyday operations to maintain the system. 
       BRIEF SUMMARY OF THE INVENTION 
       [0020]    The invention shown in  FIG. 1  is a Bed Exit Night Light System designed to illuminate a hospital room if a patient leaves his bed, but is not activated by the presence of hospital staff or casual movement of equipment. 
         [0021]    The system is based on a Control Unit  11  that monitors the Bed Sensor  13  when the Room Light  15  is off, energizing the Room Light  15  when a patient leaves the bed, and keeping the Room Light  15  on until deactivated by the patient or hospital staff. 
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
       [0022]      FIG. 1  is a block diagram of the invention. 
         [0023]      FIG. 2  is a flow chart for the invention&#39;s operation. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0024]    The invention described herein builds upon existing components of modern hospital beds, adding a Control Unit  11  that is only active when a patient&#39;s room lighting is not operating, but turns the Room Light  15  on when the room&#39;s lighting is off and a patient gets out of bed. In an alternate configuration, the invention only functions when the room is dark. In practice, the invention comprises the Control Unit  11  and new wiring connections that employ an existing bed sensor, but retro-fit kits may also include the Bed Sensor  13 , Low Voltage Light Control Relay  17 , Light Control Button  19 , and associated wiring. 
         [0025]      FIG. 1  shows a control diagram showing the physical connection between the various components of the invention. This diagram assumes that the Low Voltage Control Relay (LVCR)  17  changes state each time its inputs show a closed contact, just as the Light Control Button  19  momentarily closes its normally open contacts to change the state of the LVCR  17 . The dotted lines indicate connections that already exist in typical circumstances. 
         [0026]    The embodiment shown in  FIG. 1  assumes that the Control Unit  11  senses the 
         [0027]    Room Light  15  operation by monitoring the voltage source across the Room Light  15 . Alternatively, the Control Unit could have a light detector which eliminates that direct wired connection. 
         [0028]    As shown in  FIG. 2 , the operation begins when a user activates the system, usually by a button on the Control Unit  11  (Step  110 ). After activation, the Control Unit  11  begins to monitor the room&#39;s overhead light (Step  120 ). The Control Unit does nothing unless the Room Light  15  is off (Step  130 ). 
         [0029]    When the Room Light  15  is off, the Control Unit  11  monitors the Bed Sensor  13  to determine if a patient is present (Step  140 ). The Bed Sensor  13  is usually a “normally open” (NO) contact that closes when a patient leaves the bed; this apparatus is included in most modern hospital beds. When a patient leaves the bed, the Bed Sensor  13  changes state, informing the Control Unit  11  of the patient&#39;s activity. (Step  150 ). 
         [0030]    The Control Unit can also function with a Bed Sensor  13  that is a “normally closed” (NC) contact here as well; the invention just needs to take into account the status of the contact when a patient is in the bed, and that the status changes when a patient leaves the bed. 
         [0031]    When the Control Unit  11  is informed by the Bed Sensor  13  that a patient has left the monitored hospital bed, the Control Unit  11  activates the Low-Voltage Control Relay (LVCR)  17  that most modern hospitals use to operate the Room Light  15  (Step  160 ). 
         [0032]    When activated, the LVCR  17  energizes the Room Light  15  (Step  170 ). The 
         [0033]    Control Unit  11  ceases activity while monitoring Room Light  15  (Step  180 ). The Control Unit  11  monitors the Room Light  15  until de-energized by an outside actor (Step  190 ). 
         [0034]    The Control Unit  11  then monitors the Bed Sensor  13  (Step  200 ). Once the Room Light  15  is off, and the patient is back in bed, the Control Unit  11  repeats the cycle (Step  210 ). Alternatively, a timer can also be employed to give a patient time to settle himself before beginning to monitor movement of the patient and avoid false positives. 
         [0035]    In the current incarnation, no part of the invention turns the light off, though this could be an added feature. None of the apparatus discussed or shown interferes with the existing light control. The Control Unit  11  triggers the LVCR  17  by emulating the Light Control Button  19  by sending it a closed contact to its inputs. 
         [0036]    The point of the flow chart is that the Control Unit  11  turns the Room Light  15  on when a patient gets out of his bed and the Room Light  15  is off, and remains on until the patient or nursing staff turns the light back off. Once the Room Light  15  is on, the Control Unit  11  ignores further input until a patient or one of the hospital staff deactivates the Room Light  15  by using Light Control  19 , typically a momentary switch to turn the Room Light  15  off. Then the Control Unit  11  waits until the patient is back in bed and the light is off before starting the monitoring cycle anew. 
         [0037]    When the existing Room Light  15  illuminates the room, the patient is brought to a more awakened state when they try to exit the bed and they are able to see all of the potential tripping obstacles in their path, thereby reducing the likelihood of a patient fall. 
         [0038]    In typical use, the Control Unit  11  is a permanently-mounted device that is located above the ceiling, but could be mounted anywhere on the patient room head wall, under the bed, or any other out-of-the-way location. Unlike previous solutions to this challenging situation, it is not disturbed by staff or equipment as it is moved around in the patient&#39;s room. 
         [0039]    Since modern patient beds can sense the patient&#39;s weight and only trigger the bed exit alert when the patient&#39;s weight is lifted, false alarms are kept to a minimum. 
         [0040]    The Invention  11  also has a contact closure output that could then be used to trigger the nurse call system or bed-exit alarm.