Patent Abstract:
A safety unit for mounting in a wall defining a part of a building space has a tubular housing containing an emergency load such as a light sized to fit within the housing, said emergency load including a base and a light-emitting element. An actuator mechanism such as a motor carried on the housing provides force to the base responsive to electrical power to translate the base to deploy the emergency load within the building space. A preferred embodiment includes a cover and a cover-operating mechanism receiving force from the actuator to remove the cover as the load deploys.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a regular application filed under 35 U.S.C. §111(a) claiming priority, under 35 U.S.C. §119(e)(1), of provisional application Ser. No. 61/174,222, previously filed Apr. 30, 2005 under 35 U.S.C. §111(b). 
    
    
     BACKGROUND 
     Building codes require that public spaces have electrically operated emergency lighting and signage (collectively “emergency loads” or “safety units” hereafter) in case of a power outage so that the occupants of the building can evacuate safely. Such emergency loads of course require an auxiliary power source that functions during a power outage. 
     Common building construction uses wallboard or other types of panels mounted on studs for the walls, or on joists for ceilings to define individual occupancy spaces (rooms, halls, etc.). The spaces between the studs or joists behind the panels are usually void or occupied by insulation. Particularly in commercial buildings and multiple dwellings, some ceilings use panels that fit into metal frames suspended from I-beams or poured concrete layers. For the sake of simplicity, all of these various types of room-defining panels having voids behind them will hereafter be referred to as “walls”. 
     Many types of buildings have their emergency loads mounted in visible locations of halls, stairways, and other evacuation routes. These loads must be completely visible when deployed during power outages. But mounting these emergency loads so as to be visible when power is available may not be desirable for a couple of reasons. The emergency loads are often eyesores. And emergency loads mounted in visible locations are vulnerable to vandalism and to damage during cleaning, painting, etc. 
     These concerns have been known for a long time. Solutions have been difficult to devise. 
     BRIEF DESCRIPTION OF THE INVENTION 
     A safety unit for mounting in a wall defining a part of a building space, said safety unit activating responsive to electrical power. The safety unit comprises a tubular housing having first and second ends, with an axis extending along the length of the housing. The tubular housing is configured for mounting within a cavity of a wall with the second end of the housing substantially flush with an outer surface of the wall. 
     An emergency load such as a light source sized to fit within the housing includes a base and a light-emitting element. A guide within the housing mechanically interacts with the base, and extends generally along the housing&#39;s axis. 
     The guide&#39;s interaction with the base allows translation of the base generally along the housing from a standby position adjacent to the housing&#39;s first end to a deployed position adjacent to the housing&#39;s second end when the base receives force. The base supports the lighting element to place the lighting element within the housing when in the storage position and outside the housing when in the deployed position. 
     An actuator mechanism carried on the housing provides force to the base responsive to electrical power to shift the base between the standby and deployed positions for the emergence load. 
     One version of the safety unit includes a cover at the second end of the housing, mounted for rotation between first and second positions respectively closing and opening the second end of the housing. A linkage within the housing transmits force to the cover to rotate the cover between the first and second positions responsive to the force received from the linkage. 
     In a preferred version, the actuator mechanism comprises a motor mounted on the housing for rotating a shaft responsive to electrical power. The linkage comprises a jackscrew extending along the housing&#39;s axis receives torque from the motor and a threaded traveler carried by the jackscrew and attached to the base. The traveler shifts axially along the housing as the motor shaft rotates. 
     The linkage may further comprise a tab projecting from the base substantially transversely to the housing axis, said tab having a slot therein. An elongate strip having first and second ends mounted for rotation about its length within the housing extends along the housing&#39;s axis with the first ends of the housing and strip adjacent and the second ends of the housing and strip adjacent. The strip passes through the tab&#39;s slot with the cover attached to the second end of the strip 
     The strip has a twist therein that is preferably adjacent to the strip&#39;s first end and between the base&#39;s tab and the strip&#39;s second end. As the twist passes through the tab&#39;s slot, the strip rotates, thereby swinging the cover from the second end of the housing. 
     The strip may include on its second end a cam and follower connected between the strip and the cover. As the strip rotates, the cam and follower axially shift the cover away from the housing&#39;s second end. 
     In another embodiment, a spring is connected between the housing and the base and urging the base toward the housing&#39;s first end. The actuator comprises a motor and a fan driven by the motor and within the housing, to force a stream of air within the housing and toward the base, of strength sufficient to overcome the spring force on the base and shift the base toward the deployed position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the deployed first version of the invention. 
         FIG. 2  is a side elevation section of the first version of the invention. 
         FIGS. 3-6  are perspective views of various components of the invention. 
         FIGS. 7-10  are top and side elevation views of a second version of the invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIGS. 1 and 2  show a safety unit such as an emergency light fixture  10  suitable for fitting in the space behind or within a ceiling  28  such as a ceiling panel or a false ceiling. Fixture  10  may also fit in the space behind or within a wall.  FIG. 1  shows as fixture  10 , a deployed light source  24  such as a florescent tube. Other types of light sources such as LEDs are suitable as well. 
     An emergency power supply (not shown) provides actuating power for operating fixture  10  when power is lost to the building mains.  FIGS. 1 and 2  show fixture  10  as comprising a tubular housing  13  having a longitudinal axis and containing the fixture  10  components. Fixture  10  is suitable to fit in an opening in wall  28  and project into the void behind wall  28 . Light source  24 , is sized to fit within housing  13 . 
     In the deployed position shown in  FIG. 1 , light source  24  projects from the open end of housing  13 . Light source  24  plugs into and is supported by a mounting socket  19  that moves between the top and bottom ends of housing  13  to reach standby and deployed positions respectively.  FIG. 1  show socket  19  at the bottom end of housing  13  with light source  24  deployed. A cover  16  rotates to open housing  13 , allowing socket  19  to shift to the deployed position. 
     Housing  13  has a flange  27  at the lower end that fits against the wall  28  surface to mount housing  13  in wall  28  with its bottom end in a near-flush position. An interior peripheral flange or ring  33  of housing  13  encircles the bottom end of the housing  13  interior. 
       FIG. 2  can be better understood with reference to  FIGS. 3-6 , which show perspective views of various components of fixture  10 .  FIG. 2  shows housing  13  enclosing a carrier assembly  20  mounted to slide or shift along a substantial portion of the axial length of housing  13 . Assembly  20  supports and transports socket  19 . A guide mechanism including a traveler element  42  and a jackscrew  40  transports and guides assembly  20  to shift axially between the standby position that  FIG. 2  shows and the deployed or operating position of  FIG. 1 . 
     The carrier assembly  20  may have several different embodiments. Each of the possible embodiments have guide mechanism components along which carrier assembly  20  moves between the standby and deployed positions, and an actuator assembly at  30  for providing the force to shift carrier assembly  20  along the guide components. 
     In the embodiment of  FIG. 2 , a jackscrew  40  cooperates with a lid control shaft  51  to function as the both the guide mechanism and a part of the actuator assembly  30 . The actuator assembly  30  includes a motor  48  and a gear train  45  that motor  48  drives. The output gear (not visible in  FIG. 2 ) of gear train  45  supports an end of and drives jackscrew  40 . A bearing  36  mounted on flange  33  supports the lower end of jackscrew  40  for rotation. The jackscrew output gear and the bearing  36  hold jackscrew  40  with little or no axial runout. 
     A jackscrew traveler element  42  connects to socket  19  and is in threaded engagement with jackscrew  40 . The axial length of traveler element  42  is adequate to hold carrier assembly  20  and light source  24  in axial alignment with housing  13 . 
     As actuator assembly  30  rotates jackscrew  40 , traveler element  42  moves axially along jackscrew  40 , shifting carrier assembly  20  between the standby and deployed positions. Motor  48  is reversible to allow carrier assembly  20  to shift between the standby and deployed positions. 
       FIGS. 4 and 5  show the lid control shaft  51  as having the form of an elongate metal strip. Shaft  51  is mounted for rotation within a hole in a bearing  57  attached to actuator assembly  30  and through a hole in an element  38 B fixed in a hole in flange  33 . An extension spring  61  attached between the upper end of shaft  51  and the closed (upper) end of housing  13  continuously urges shaft  51  upwards (toward the closed end) of housing  13 . 
     A tab  35  projecting transversely from carrier assembly  20  has a slot  36  shown in  FIGS. 5 and 6  through which shaft  51  also passes. Shaft  51  includes a section  54  having an approximately 180° twist, although a twist of as little as one-fifth of a revolution may be adequate. The twist must swing lid  16  sufficiently from the opening of housing  13  to allow light source  19  to reach its deployed position without interference from lid  16 . 
     As carrier assembly  20  moves toward the deployed position, a slot  36  in tab  35  (see  FIGS. 3 ,  5 ) traverses through twisted section  54 . While traversing through section  54 , slot  36  in tab  35  causes shaft  51  to rotate within element  38 B and bearing  57 , through the approximately 180° twist in section  54 . 
     The lid actuator assembly components shown in  FIG. 6  comprise elements  38 A and  38 B. Elements  38 A and  38 B have between them, a sloped interface at  39  in the form of a cam and follower. Element  38 A is fixed to lid  16  and attached to tab  51 A ( FIG. 4 ) of shaft  51  by pin  52  ( FIG. 6 ). 
     During the portion of a deployment while slot  36  traverses section  54 , shaft  51  rotates approximately 180°. The rotation of shaft  51  causes the sloped interface  39  to translate element  38 A and lid  16  axially downwards from flange  27  while lid  16  rotates away from the opening at the bottom of housing  13  into the position shown in phantom at  16 ′. The axial position of twisted section  54  creates this translation and rotation of lid  16  before the bottom end of light source  24  reaches the upper surface of lid  16 . Spring  61  provides constant axial force on shaft  51  urging shaft  51  and lid  16  upwards during deployment and then while deployed. 
     Fixture  10  activates when receiving power at a connector  68 . Cable  69  conducts current to base  19  for powering light source  19 . Cable  69  also carries current to a switch  67  mounted on carrier assembly  20 . Switch  67  controls power to drive motor  48 . A lever  67 A on switch  67  operates to close switch  67  when contacting a feature on flange  33 , which occurs as carrier assembly  20  nears the fully deployed position. Switch  67  contains a second contact set controlled by a lever, not shown, to stop motor  48  as base  19  completes retraction to the standby state. 
       FIGS. 7-10  show an emergency light fixture  10 ′ with a second type of actuator mechanism. Reference numbers track those in  FIGS. 1-6  where appropriate. 
     Carrier assembly  20 ′ supports a bank of LEDs  86 . A pair of counterbalance springs  83 A and  83 B support carrier  20 ′ in the standby position. 
     The top views of  FIGS. 7 and 9  show a fan  80  (comprising a motor and impeller) mounted within housing  13  on the cover  85 .  FIGS. 7 and 9  show the cover  85  of housing  13  with slots or louvers  89  through which fan  80  draws and downwardly directs air toward carrier  20 ′. 
     Fan  80  serves as the actuator mechanism to provide aerodynamic force on carrier assembly  20 ′ that exceeds the support force of springs  83 A and  83 B. The aerodynamic force of fan  86  pushes carrier assembly  20 ′ from a standby position toward the deployed position shown at  86 ′ in  FIGS. 8 and 10 , with the deployed LED bank  86  projecting from housing  13 . 
     High output LEDs generate a substantial amount of heat. Fan  80  also functions to cool the LED bank  86  when in the deployed position and producing light. Lid  16  may be supported by a mechanism similar to that shown in  FIGS. 2-6 . 
     Fan  80  may be reversible so air can be forced in either direction within and along the axis of housing  13 . In this case springs  83 A and  83 B may be much weaker than if they provide all of the retracting force. Friction in combination with the force of springs  83 A and  83 B holds carrier assembly  20 ′ in the standby position. 
     A reversible fan  80  may even make springs  83 A and  83 B unnecessary for retracting assembly  20 ′. A spring finger or other friction-generating element that carrier assembly  20 ′ carries may rub against housing  13  to create drag for holding assembly  20 ′ in place. These designs require fan  80  to generate aerodynamic retraction force on assembly  20 ′ sufficient to overcome both the drag force and the weight of assembly  20 ′ when fixture  10  is installed in a ceiling. 
     Alternately a detent notch may cooperate with a finger to securely maintain assembly  20 ′ in the retracted position. Fan  80  force is greatest when assembly  20 ′ is in standby position, allowing fan  80  to overcome the detent force. 
     To cool LED banks  86 , fan  80  may continue to run after completing retraction of assembly  20 ′.

Technology Classification (CPC): 5