Abstract:
An emergency lighting fixture includes a door and light source disposed on the door. The door rotates 360 degrees in one direction. A slip clutch assembly permits manual rotation of the door when obstructed by a motor or to remain in the same position when obstructed during rotation by the motor. A capacitor stores energy to close the door. A pressure locking assembly includes a bearing ball biased into engagement with an alignment hole by a spring in response to the door being rotated near a predetermined position. A conductive clip maintains electrical contact with a conductive portion of a hinge as the door rotates. The conductive clip is connected to a power source, and the light source is connected to the conductive portion of the hinge, thereby providing power to the light source after the door has stopped in a pre-determined position or during rotation of the door. The fixture may be used in non-emergency lighting applications.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 60/920,717, filed Mar. 29, 2007, the disclosure of which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention generally relates to emergency lighting fixtures. In particular, the present invention provides various improvements in a concealed emergency lighting fixture. 
         [0004]    2. Description of the Related Art 
         [0005]    The majority of the prior art is based on a lamp module or box, which includes lamps for emergency lighting and has one or two doors aligned with a mounting wall or ceiling surface. The conventional solutions differentiate themselves by various methods used to open and close the door(s) and the position of the lamps during the emergency lighting. 
         [0006]    For example, the device described in U.S. Pat. Nos. 5,025,349; 5,682,131; and 6,097,279 to Gow open and close the door with a motor. The motor is supplied with a reverse polarity voltage to change the sense of rotation when the door is closed, which creates a flip-flop operation. However, this method requires the presence of an external power source (24 Vdc or the like) to close the door. 
         [0007]    U.S. Pat. No. 6,164,788 to Gemmel et al. uses a steel spring to open the door and a motor to close the door and compress the spring. However, this method requires the presence of a second power source (AC line) to close the door. 
         [0008]    U.S. Pat. No. 5,851,061 to Hegarty uses a mirror installed on the back of the door to reflect the light from the lamp, which is fixed inside the fixture. A solenoid opens and closes the door. However, the light beams are difficult to orient during installation (indirect lighting) and there is a significant loss of light output due to light absorption from reflection. 
         [0009]    U.S. Pat. No. 4,802,065 to Minter uses gravitational force to open the doors. The fixture described in this patent is mounted in a ceiling and two doors drop open to allow the lamps to descend for emergency lighting. The two open doors limit the access of each light beam to about half the floor in the room. However, this fixture requires two linear motors or two solenoids to close the doors. In addition, this fixture is not suitable for installation in walls. 
         [0010]    U.S. Pat. No. 6,371,621 to Le Bel describes a complex “pulse proportional servo-motor” to open and close a door, which rotates by only 90 degrees. However, this product is expensive (since it requires a special motor) and the lamps cannot be aimed in all directions within the room. 
       SUMMARY OF THE INVENTION 
       [0011]    An emergency lighting fixture formed in accordance with one form of the present invention, which incorporates some of the preferred features, includes a light source and a door. The light source is disposed on the door. The door is adapted to rotate a full 360 degrees in the same direction about an axis, thereby enabling the light source to be selectively concealed and exposed by rotation of the door in one direction. The door may also be adapted to rotate 360 degrees in two directions. The fixture may include a slip clutch assembly adapted to permit the door to be manually rotated when obstructed from doing so by a motor and/or to permit the door to remain in the same position in response to being obstructed during rotation by the motor. 
         [0012]    The fixture may also include a capacitor that stores electrical energy sufficient to close the door. The fixture may include one or more switches to detect a predetermined rotational position of the door. The switches may be activated by a cam that rotates with the door. The fixture may also include a pressure locking assembly, which includes a bearing ball, spring, and alignment hole. The bearing ball is biased into engagement with the alignment hole by the spring in response to the door being rotated near a predetermined position. The predetermined position may be when the rear surface of the door faces forward and/or rearward. 
         [0013]    The fixture may further include a hinge, about which the door is rotated, and a conductive clip. The hinge may include an electrically conductive portion and the conductive clip maintains electrical contact with the conductive portion of the hinge as the door is rotated. The conductive clip is electrically connected to a power source and the light source is electrically connected to the electrically conductive portion of the door, thereby providing power to the light source during rotation of the door. The fixture may include a DC power source, AC power source, low-voltage power source, and/or mains voltage power source. The emergency lighting fixture may also be adapted for use in non-emergency lighting applications. 
         [0014]    The emergency lighting fixture may also include a motor adapted to rotate the door about the at least one axis, a first voltage regulator, and a second voltage regulator. The first voltage regulator is operatively coupled to the motor, and the motor is adapted to expose the light source in response to receiving power from the first voltage regulator. The second voltage regulator is operatively coupled to the motor, and the motor is adapted to conceal the light source in response to receiving power from the second voltage regulator. The emergency lighting fixture may also include a diode operatively coupled in series between the first voltage regulator and the motor, a switching device operatively coupled in series between the second voltage regulator and the motor, and a capacitor operatively coupled in parallel across ground and a node between the second voltage regulator and the switching device. The switching device is open when the motor is receiving power from the first voltage regulator, and closed when the motor is not receiving power from the first voltage regulator, thereby providing power from the capacitor to the motor to conceal the light source. 
         [0015]    A method of providing light in an emergency in accordance with one form of the present invention, which incorporates some of the preferred features, includes disposing a light source on a door, and rotating the door at least 360 degrees in at least one direction about at least one axis, thereby enabling the light source to be selectively concealed and exposed. The method may include rotating the door at least 360 degrees in at least two directions about the at least one axis, configuring the door to be manually rotated about the at least one axis when obstructed from doing so by a motor, and configuring the door to remain fixed when obstructed and a motor is attempting to rotate the door. The method may further include storing electrical energy sufficient to close the door, and adapting the emergency lighting fixture for use in non-emergency lighting applications. The method may still further include rotating the door about the at least one axis using a motor, wherein the motor is adapted to expose the light source in response to receiving power from a first voltage regulator, and to conceal the light source in response to receiving power from a second voltage regulator. 
         [0016]    These and other objects, features, and advantages of this invention will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIGS. 1   a - 1   i  are pictorial views of an emergency lighting fixture in accordance with the present invention in various stages as the fixture rotates through a complete 360 degrees. 
           [0018]      FIGS. 2   a  and  2   b  are side and rear perspective views, respectively, of the emergency lighting fixture. 
           [0019]      FIGS. 3   a  and  3   b  are side views of the emergency lighting fixture when the fixture is in a closed state and an open state, respectively. 
           [0020]      FIG. 4  is a perspective view of a door assembly used in the emergency lighting fixture. 
           [0021]      FIG. 5  is a more detailed view of a hinge mechanism used in the emergency lighting fixture. 
           [0022]      FIG. 6  is a side perspective view of the emergency lighting fixture in a partially open state. 
           [0023]      FIG. 7   a  is a more detailed view of the hinge mechanism used in the emergency lighting fixture. 
           [0024]      FIG. 7   b  is an exploded view of the hinge mechanism used in the emergency lighting fixture. 
           [0025]      FIG. 8   a  is a block diagram of an electrical circuit used in the emergency lighting fixture. 
           [0026]      FIG. 8   b  is a side view of a hinge cam mechanism with electrical switches used in the emergency lighting fixture. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0027]    The present invention is directed to an emergency lighting fixture  10  shown in  FIGS. 1   a - 1   i , which is designed for concealed installation in ceilings or walls of buildings. A lamp module includes emergency lights  12 ,  14  shown in  FIGS. 1   d - 1   h . The lamp module is preferably recessed in a wall (or ceiling) and it includes a door  16 , which is aligned with the surface of the wall. One of the primary features is that the door  16  is installed with two hinges that are able to rotate 360 degrees, which is illustrated in  FIGS. 1   a - 1   i.    
         [0028]    The lamps or emergency lights  12 ,  14  are installed on the back of the door  16 . During a power failure, a miniature motor preferably turns the door by 180 degrees and exposes the lamps  12 ,  14 , which will illuminate the path of egress. The lamps  12 ,  14  can be oriented in virtually any direction in space (preferably 360 degrees horizontal and ±90 degrees vertical). At the end of the power outage, the door  16  closes by rotating 180 degrees in the same direction as before, which enables a full 360 degree rotation. The motor and the door  16  preferably always turn in the same direction, which makes the gear design simple and cost-effective in comparison with traditional “flip-flop” mechanisms of door movement. 
         [0029]    A second feature of the emergency lighting fixture  10  is a simple slip clutch included in the transmission mechanism. This device allows the rotation of the motor and other gears even when an obstacle blocks the door movement. This feature protects the electrical motor from overcharge and also protects people during accidental mishandling of the fixture. The slip clutch mechanism also allows the user to force-open and force-close the door during installation or maintenance of the equipment. The slip clutch preferably has a simple construction, is built-in the door hinge, and does not require calibration. 
         [0030]    A third feature of the emergency lighting fixture  10  is a circuit that uses a capacitor or other energy storing device, such as a battery, to store the electrical energy required to close the door. The circuit charges the capacitor during power-up, as well as before and while the door opens. When the external emergency power supply is disconnected or fails, the lamps  12 ,  14  preferably turn off and the capacitor supplies the motor with stored electrical energy, which closes the door. The advantages of this invention include energy savings (no power consumption for the motor, clutches, and the like during the emergency period), lower cost, and no need for a second line of power (AC line voltage) to close the door. 
         [0031]    Regarding the door and hinges, the invention preferably uses a lamp box with one door  16  mounted with two axial hinges, installed on the central axis of the door as shown in  FIGS. 1   a - 1   i . The hinges allow the door  16  to rotate easily for 360 degrees around its central axis, with multiple turns in the same direction. The two emergency lamps  12 ,  14  are preferably installed on the back of the door  16 . When the door  16  is closed, the lamps  12 ,  14  are concealed in the box. When the door opens (turns 180 degrees), the lamps  12 ,  14  are completely exposed towards the room and can be aimed in virtually any direction in space. 
         [0032]    One of the two door hinges preferably has its axle terminated with a spur gear  18  and can slide (rotate) in the hinge housing. The spur gear  18  is further connected through a gear mechanism  20 ,  22  to a linear motor  24  shown in  FIGS. 2   a  and  2   b . The motor  24  preferably opens and closes the door  16  by rotating continuously in the same direction. The second hinge of the door preferably has its axle terminated with a cam  26 . This axle is preferably solidly or rigidly connected with the hinge housing. Thus, the cam  26 , spur gear  18 , and square tube  48  shown in  FIGS. 7   a  and  7   b  are not attached to the hinges, but are preferably part of the hinge axles. The cam end of the axle is preferably held rigid or locked in its hinge housing  51  by a protrusion  53  extending from the cam end housing  51  that engages with a slot in the cam  26  axle. The spur gear end of the axle can preferably slip or rotate in its hinge end housing  50 , which preferably includes an opening to allow the square tube  48  to rotate therein. 
         [0033]    Two electrical switches  28 ,  30  are positioned along the diameter of the cam, as shown in  FIGS. 3   a  and  3   b . The cam  26  preferably activates sequentially each switch  28 ,  30  when the door  16  is either closed or completely open (180 degree turn). The two switches  28 ,  30  are preferably connected to an electrical circuit designed to control the motor  24  that, for example, stops the motor  24  when the door  16  is completely open or completely closed. 
         [0034]    The door  16  is preferably aligned in a closed or open position by a pressure locking mechanism built with bearing balls  32  and steel springs  34  shown in  FIGS. 4 and 5 . Two bearing balls  32  and springs  34  are preferably installed in the body of each hinge shown in  FIG. 5 . The lateral walls of the fixture housing preferably include alignment holes  36  that engage with the balls  32  as shown in  FIG. 6 . When the door is almost closed (or almost completely open) and the motor  24  is turned off, the balls  32  preferably snap in the alignment holes  36 , which stops the door inertial movement of the door. 
         [0035]    Regarding the sliding electrical connectors, the two hinges are preferably made of an electrically isolating material, such as, but not limited to, a plastic, and include a hole  40  along their longitudinal axis. Each hinge preferably includes a metallic cylinder  38  installed in the hole  40 , which functions as an electrical connection between the lamps  12 ,  14  and the wires  47  installed on the fixture frame shown in  FIGS. 2 and 3 . On the door side of the hinge, the lamp wires  44  are fixed with screws at one end of each cylinder. At the other end (fixture housing), metal spring clips  42  are snapped onto the metallic cylinder head  38  as shown in  FIG. 6 . The clips  42  preferably slides during the rotation of the metallic cylinder  38 , which maintains the electrical connection necessary to provide power to the lamps  12 ,  14 . The two spring clips  42  are further connected to wires  47 , which are fixed on the lamp box to an emergency power source. The two metal cylinders  38  and their sliding clips  42  enable electrical connection of the mobile lamps, which rotate with the door, to the fixed lamp housing and external emergency power source, which is preferably a battery circuit. Even if the metallic cylinder  38  provides electrical connection at all times, in the preferred embodiment, the lamps are only powered when the door is completely open, which is when the cam  26  releases the switch SW 1   28 . Alternatively, the lamps may be powered at all times. 
         [0036]    Regarding the slip clutch mechanism shown in  FIGS. 7   a  and  7   b , the connection of the hinge to the spur gear  18  is loose in the gear axis, allowing the spur gear  18  to rotate (slip) independently from the hinge body  46  and the metal cylinder  38 . However, to allow a controlled slip torque between these components, the spur gear  18  is preferably terminated with the square tube  48 . The upper part of the hinge body or housing  50  preferably includes a metal plate  55  firmly held in contact with the square tube  48  by two steel springs  52  held in place with screws  54 .  FIG. 7   b  also shows caps  57 , which are preferably made from plastic, that are used to cover and electrically isolate the spring clips  42  at the ends of the metallic cylinders  38 . The caps  57  preferably include pin extensions that lock in the metal frame to prevent the cap and wire from rotating when the door and metal cylinders turn. 
         [0037]    During normal operation, the pressure exercised by the two springs  52  and the metal plate  55  on the square tube  48  preferably keeps the hinge axle from rotating on the hinge body  46  independently of the motor and allows the torque of the spur gear  18  to engage the door  16  during rotation. However, if the door  16  is blocked while the motor  24  and spur gear  18  are in motion, the torque force of the square tube  48  will apply an upward force to the metal plate  55 , which will eventually compress the two springs  52  to disengage the slip clutch mechanism for about a quarter of a turn (90 degrees). If, after this, the door is still locked, the clutch will continue to slip periodically by about a quarter turn, until the motor stops or the door is released. In addition, if the spur mechanism  18  is locked and the motor has stopped, one can force the door  16  open or closed and access the inside of the fixture by forcing the door open, thereby engaging the same slip clutch mechanism. 
         [0038]    The energy storage circuit  56  shown in  FIG. 8   a  preferably controls the power supply to the motor (start and stop function) in response to activation of the emergency power supply and the position of the two door switches  28 ,  30 . The circuit  56  preferably transfers electrical power to the lamps only while the door is completely open, which prevents accidental overheating of the fixture. 
         [0039]    The electrical circuit  56  preferably includes a capacitor C 1 , which is able to store the energy required by the motor  24  to rotate the door  16  until it is closed. 
         [0040]    When the emergency lighting fixture  10  is powered by a voltage V+, a voltage regulator U 1  provides current via the diode D 1  and switch SW 1  to the motor  24 , which drives the door to open. Electrical current to the motor is limited in value by the regulator U 1  to prevent overheating during abnormal conditions, such as when the motor or gear are restricted from moving. When the door is completely open, the switch SW 1   28  preferably changes state, which turns the motor  24  off and supplies current to a control circuit  59  to power the lamps  12 ,  14 . This is the emergency lighting state. 
         [0041]    At the same time, after the power supplies the voltage V+, a second voltage regulator U 2  preferably charges the capacitor C 1 . The charging current is preferably limited in value by the regulator U 2  in accordance with the electrical specifications of the capacitor C 1 . In the emergency lighting state the control circuit  58  preferably keeps transistor Q 1  off, which isolates capacitor C 1  from the motor circuit. 
         [0042]    When the emergency power is disconnected, that is V+=0, a close door control circuit  58  preferably turns transistor Q 1  on. The capacitor C 1  then preferably supplies current through transistor Q 1  and switch SW 2   30  to the motor  24 , which starts rotating the door. When the door is completely closed, the switch SW 2   30  preferably disconnects the power supply and the motor  24  stops. The capacitor C 1  is preferably fully recharged when the fixture is powered and the door opens. 
         [0043]    The advantages of the emergency lighting fixture in accordance with the present invention include:
       1. Full orientation in space of the emergency lamps since the door opens by turning 180 degrees.   2. The opening and closing of the door is achieved with only one simple (linear) motor. Thus, there is no need to rely on gravitational force, which would make it impossible for the fixture to be wall-mounted), mirrors, additional springs to open or close the door, and the like.   3. A cost-efficient simple mechanism that is easy to install without the need for torque calibration, since the torque (slip force) of the slip clutch mechanism is controlled by springs, and the motor does not consume power when the door is idle.   4. The electrical circuit does not require external power, such as an AC power line, to close the door.       
 
         [0048]    It is to be noted that a concealed emergency lighting fixture in accordance with the present invention can also be used for general lighting applications. Further, the external power source can supply DC and/or AC current. In addition the external power source may be low-voltage or mains voltage, such as an AC power line. It is also to be noted that the concealed lighting fixture in accordance with the present invention can use less than four (4) bearing balls such as one, two, or three bearing balls for door alignment. 
         [0049]    Although illustrative embodiments of the present invention have been described herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various other changes and modifications may be affected therein by one skilled in the art without departing from the scope or spirit of the invention.